MX2008001757A

MX2008001757A - A fuel injection system for an internal combustion engine

Info

Publication number: MX2008001757A
Application number: MXMX/A/2008/001757A
Authority: MX
Inventors: Allen Jeffrey
Original assignee: Scionsprays Limited
Priority date: 2005-08-05
Filing date: 2008-02-05
Publication date: 2008-09-02

Abstract

With reference to Figure 1, the present invention provides an internal combustion engine (10) comprising a variable volume combustion chamber (13);an air intake system (18,20,21) for delivering charge air to the combustion chamber (13);an exhaust system (17) for relaying combusted gas from the combustion chamber (13) to atmosphere;and a fuel injection system (19, 21, 22, 23, 24, 25, 26) for delivering fuel into the charge air for combustion therewith in the combustion chamber (13). The fuel injection system (19,21,22,23,24,25,26) comprises a fuel injector (19) which functions as a positive displacement pump and dispenses an amount of fuel which is fixed for each and every operation of the injector (19);and a controller (23) which controls the operation of the fuel injector (19). In. response to an increasing engine speed and/or load the controller (23) increases in amount the fuel delivered per engine cycle by increasing in number the occasions the fuel injector (19) is operated per engine cycle. In response to a decreasing engine speed and/or load the controller (23) reduces in amount the fuel delivered per engine cycle by reducing in number the occasions the fuel injector (19) is operated per engine cycle.

Description

FUEL INJECTION SYSTEM FOR A N INTERNAL COMBUSTION ENGINE Field of the Invention The present invention relates to a fuel injection system for an internal combustion engine. BACKGROUND OF THE INVENTION Most internal combustion engines in automobiles currently use fuel injection systems to supply the fuel to the combustion chambers of the engine. Injection systems have replaced the previous technology of carburetors because they give more control of the fuel supply and allow the engine to meet legal emissions targets as well as improve overall engine efficiency. The injectors currently in use are modulated in their pulse width. This means that each injector is operated for a selected period of time in each engine cycle, to the length of time that the injector is open dictates the volume of fuel supplied to the engine chamber in that cycle. Typically, those pulse width modulated fuel injection systems use a fuel supply with a fixed pressure or a precisely known substantially constant pressure and on / off valves that can be activated for a predetermined period of time under the control of an electronic controller. The result of such a combination of known and variable but controlled pressure, the opening times give an injection of known quantities of fuel in the combustion chambers of the engine. The method described above is used for all gasoline injection systems (both port and direct injection systems) and also high pressure common rail diesel injection systems which are the most novel in the art. The latest diesel fuel injection systems by direct injection in common rail sometimes use multiple injection pulses to better disperse the fuel inside the cylinder and give better combustion results, but each of these pulses have a variable time (although some time). much shorter than previous single-pulse fuel injection systems) and the controller will set the opening time of the injector on each pulse in order to accurately control the amount of fuel supplied. All prior art systems therefore require a pump, a pressure regulator and an injector (which effectively functions as an on / off valve) and a sophisticated electronic control module to control the opening time of each injector. The injectors used in the systems of injectors of previous fuels that operated slowly and suffered from lack of repeatability). The newer injectors are capable of opening and closing in less than one millisecond. Although sophisticated and highly developed fuel injection systems are ideal for use in internal combustion engines in automobiles, there are many other applications for internal combustion engines where that level of sophistication is not appropriate and is too expensive. For example, small low power single cylinder motors used for mowers, chain saws, small generators, scooters, mopeds, etc. They are built with very tight budgets and have low power, therefore they can not afford a sophisticated injection system nor the power required to run a fuel pump that provide the pressurized fuel required by the sophisticated fuel injection systems currently available. . To date, these small engines have used traditional technology with carburetors. However now it is the case that these small engines will face the same legislation on exhaust emissions as the engines in cars and must be modified to meet emissions targets. Therefore a simple and simple way of fuel injection is required for those small engines. Brief Description of the Invention The present invention provides in a first aspect an internal combustion engine comprising: a variable volume combustion chamber; an air intake system to supply air to the combustion chamber; an exhaust system for expelling the burned gas from the combustion chamber to the atmosphere, and a fuel injection system for supplying fuel in the charge air for combustion in the combustion chamber; wherein the injection system comprises: a fuel injector that functions as a positive displacement pump and supplies the amount of fuel that is fixed for each and every operation of the injector; and a controller that controls the operation of the fuel injector; wherein in each of at least a majority of engine cycles the fuel injector is operated on a plurality of occasions by means of the controller; in response to an increase in engine speed and / or controller load the amount of fuel supplied per engine cycle increases as the number of times the fuel injector is operated per engine cycle increases; and in response to the reduction of engine speed and / or load the controller reduces the amount of fuel supplied per engine cycle by reducing in number the occasions that the fuel injector is operated per engine cycle. The present invention in a second aspect an internal combustion engine comprising: a combustion chamber of variable volume; an air intake system to supply air to the combustion chamber; an exhaust system to expel the burned gas from the combustion chamber to the atmosphere; and a fuel injection system for supplying fuel to the air for combustion to take place with it in the combustion chamber, wherein the fuel injection system comprises: a plurality of fuel injectors of which each operates as a positive displacement pump and supplies a quantity of fuel that is fixed for each and every operation of the injector; at least a first fuel injector of the plurality of fuel injectors that supplies a fixed amount of fuel different from a second fixed quantity supplied by a second fuel injector of the plurality of fuel injectors; and a controller that controls the operation of each of the plurality of fuel injectors: wherein: in each of the at least a majority of engine cycles of the fuel injectors are operated on a plurality of occasions by the controller; in response to the increase in engine speed and / or engine load the amount of fuel increases for the engine cycle as the number of times the fuel injectors are operated by engine cycles increases; and in response to the reduction of the engine speed and / or the load of the controller the fuel supplied per engine cycle is reduced in quantity by reducing the number of occasions that the fuel injectors are operated by engine cycles.

In a third aspect, the present invention provides an internal combustion engine comprising: a variable volume combustion chamber; an air intake system to supply charge air to the combustion chamber; an exhaust system to expel burned gas from the combustion chamber into the atmosphere; and a fuel injection system for supplying the fuel in the cargo air to be burned with it in the combustion chamber; wherein the fuel injection system comprises: a fuel injector that functions as a positive displacement pump and supplies a quantity of fuel that is fixed for each and every operation of the injector; and a controller that controls the operation of each of the plurality of fuel injectors: wherein: in each of the at least a majority of engine cycles of the fuel injectors are operated on a plurality of occasions by the controller; in response to the increase in engine speed and / or engine load the amount of fuel increases for the engine cycle as the number of times the fuel injectors are operated by engine cycles increases; and in response to the reduction of the engine speed and / or the load of the controller the fuel supplied per engine cycle is reduced in quantity by reducing the number of occasions that the fuel injectors are operated by engine cycles; and the fuel injector comprises: a housing in which a fuel chamber is formed; an electric coil; and a piston that slides axially in a hole in the housing under the action of the electric coil to eject the fuel out of the fuel chamber, the piston slides between two end stops which ensure that the piston has a travel distance fixed in each operation. In a fourth aspect, the present invention provides an internal combustion engine comprising; a combustion chamber with variable volume; an air intake system to supply charge air to the combustion chamber; an exhaust system to expel burned gas from the combustion chamber into the atmosphere; and a fuel injection system for supplying the fuel in the cargo air to be burned with it in the combustion chamber; wherein the fuel injection system comprises: a plurality of fuel injectors of which each operates as a positive displacement pump and supplies a quantity of fuel that is fixed for each and every operation of the injector, at least one first injector of fuel of the plurality of fuel injectors supplying a fixed amount of fuel different from a second fixed quantity supplied by a second fuel injector of the plurality of fuel injectors; a controller that controls the operation of each of the plurality of fuel injectors: wherein: in each of the at least a majority of engine cycles of the fuel injectors are operated on a plurality of occasions by the controller; in response to the increase in engine speed and / or engine load the amount of fuel increases for the engine cycle as the number of times the fuel injectors are operated by engine cycles increases; in response to the reduction of the engine speed and / or the load of the controller the fuel supplied per engine cycle is reduced in quantity by reducing the number of occasions that the fuel injectors are operated by engine cycles; and each fuel injector comprises: a housing in which a fuel chamber is formed; an electric coil; and a piston that slides axially in a hole in the housing under the action of the electric coil to eject the fuel out of the fuel chamber, the piston slides between two end stops which ensure that the piston has a travel distance fixed in each operation. In a fifth aspect, the present invention provides an internal combustion engine comprising: a variable volume combustion chamber; an air intake system to supply charge air to the combustion chamber; an exhaust system to expel burned gas from the combustion chamber into the atmosphere; and a fuel injection system for supplying the fuel in the cargo air to burn with it in the combustion chamber; wherein the fuel injection system comprises: a fuel injector that functions as a positive displacement pump and supplies a quantity of fuel that is fixed for each and every operation of the injector; and a controller that controls the operation of each of the plurality of fuel injectors: wherein: in each of the at least a majority of engine cycles of the fuel injectors are operated on a plurality of occasions by the controller; in response to the increase in engine speed and / or engine load the amount of fuel increases for the engine cycle as the number of times the fuel injectors are operated by engine cycles increases; and in response to the reduction of the engine speed and / or the load of the controller the fuel supplied per engine cycle is reduced in quantity by reducing the number of occasions that the fuel injectors are operated by engine cycles; and the fuel injector is driven mechanically by means of a cam surface, the fuel injector has a piston driven by means of a thrust spring and displaceable by means of the cam surface, with the movement of the piston in one direction extra fuel towards a fuel chamber of the fuel injector and the movement of the piston in the other direction expels the fuel out of the fuel chamber, the surface of cams comprises a plurality of cam lobes each of which can drive the piston during each engine cycle and the controller controls how many cam lobes in each engine cycle cause the piston to eject fuel out of the fuel injector.; the fuel injector has a fuel outlet through which the fuel is expelled out of the chamber by means of the piston and a fuel inlet through which the fuel is introduced into the fuel chamber, the fuel injector it also has a one-way inlet valve that serves to allow fuel to flow into the fuel chamber from the fuel inlet while preventing the flow of fuel back from the fuel chamber to the fuel inlet and a fuel valve. output of a path that serves to allow fuel to flow out of the combustion chamber towards the fuel outlet while preventing the flow back to the fuel chamber from the fuel outlet; and the one-way inlet valve can be disabled by the controller and when it is disabled allows the fuel flow back to the fuel chamber to the fuel inlet, the movement of the piston when the one-way valve is disabled serves only to Extract the fuel from the fuel inlet to the fuel chamber and then expel the fuel out of the fuel chamber back to the fuel inlet. In a sixth aspect, the present invention provides an internal combustion engine comprising; a combustion chamber with variable volume; an air intake system to supply charge air to the combustion chamber; an exhaust system to expel burned gas from the combustion chamber into the atmosphere; and a fuel injection system for supplying the fuel in the cargo air to be burned with it in the combustion chamber; wherein the fuel injection system comprises: a plurality of fuel injectors of which each operates as a positive displacement pump and supplies a quantity of fuel that is fixed for each and every operation of the injector, at least one first injector of fuel of the plurality of fuel injectors supplying a fixed amount of fuel different from a second fixed quantity supplied by a second fuel injector of the plurality of fuel injectors; a controller that controls the operation of each of the plurality of fuel injectors; wherein: in each one of the at least a majority of engine cycles of the fuel injectors are operated on a plurality of occasions by the controller; in response to the increase in engine speed and / or engine load the amount of fuel increases for the engine cycle as the number of times the fuel injectors are operated by engine cycles increases; in response to the reduction of the engine speed and / or the load of the controller the fuel supplied per engine cycle is reduced in quantity by reducing the number of occasions that the fuel injectors are operated by engine cycles; and each fuel injector is driven mechanically by means of a cam surface, the fuel injector has a piston driven by means of a thrust spring and displaceable by means of the cam surface, with the movement of the piston in a direction of travel. extra fuel towards a fuel chamber of the fuel injector and the movement of the piston in the other direction expels the fuel out of the fuel chamber, the surface of cams comprises a plurality of cam lobes each of which can drive the piston during each engine cycle and the controller controls how many cam lobes in each engine cycle cause the piston to eject fuel out of the fuel injector.; each fuel injector has a fuel outlet through which the fuel is expelled out of the chamber by means of the piston and a fuel inlet through which the fuel is introduced into the fuel chamber, the fuel injector it also has a one-way inlet valve that serves to allow fuel to flow into the fuel chamber from the fuel inlet while preventing the flow of fuel back from the fuel chamber to the fuel inlet and a fuel valve. output of a path that serves to allow fuel to flow out of the combustion chamber towards the fuel outlet while preventing the flow back to the fuel chamber from the fuel outlet; and the one-way inlet valve can be disabled by the controller and when it is disabled allows the fuel flow back to the fuel chamber to the fuel inlet, "the movement of the piston when the one-way valve is disabled serves only to extract the fuel from the fuel inlet to the fuel chamber and then expel the fuel out of the fuel chamber back to the fuel inlet. Brief Description of the Drawings Figure 1 is a schematic representation of an internal combustion engine with a fuel injection system according to the present invention; Figure 2 is a schematic illustration of a first type of fuel injector according to the present invention suitable for use in the engine of Figure 1; Figure 3 is a schematic illustration of a second type of fuel injector suitable for use in the engine of Figure 1; Figure 4 illustrates a modification of the fuel injector of Figure 3; Figure 5 is a schematic illustration of a third type of fuel injector suitable for use in the engine of Figure 1; Fig. 6 illustrates a modification of the fuel injector of Fig. 5; Figure 7 is a schematic illustration of a fourth type of fuel injector suitable for use in the engine of Figure 1; Figures 8a), b), c) and d) illustrate the operation of the fuel injector of Figure 7; Figure 9 is a more detailed illustration of the fuel injector of Figure 7; Figures 1 0a) to 10d) illustrate the operation of a modified version of the fuel injection of Figures 7 to 9; Figure 1 1 illustrates a one-way check valve of the fuel injector of Figures 7 to 9; Figure 12 illustrates a one-way check valve of the fuel injector of Figures 1 a) to 10d); Figure 1 3 illustrates a one-way check valve that could be used in the fuel injector of some of Figures 7 to 10d); instead of the check valves illustrated; Figure 14 shows the type of signal used in the prior art fuel injection systems to control the amount of fuel supplied to the combustion chamber in each engine cycle; Figure 1 4 shows the control signal used by the present invention to activate the fuel injector of Figure 1 (for example a fuel injector of the type of any of Figures 2 to 1 0d) in order to control the amount of fuel supplied in the combustion chamber in each operating cycle; Figure 1 6 shows in: Figure 16a) a rotation signal taken from a camshaft or crankshaft of an engine of the engine of Figure 1; Figure 16b) a control signal generated for the operation at full load of the engine of Figure 1; FIG. 1 6c) a control signal generated for the partial load operation of the motor of FIG. 1; Figure 16d) a control signal generated for the operation of the vacuum motor of the engine of Figure 1; FIG. 1 6e) a control signal generated during the starting of the motor of FIG. 1; Fig. 17 is a schematic representation of the input passage of the internal combustion engine of Fig. 1 with a slightly modified version of the fuel injector of Fig. 3; Figure 18 shows a cross-sectional view of a nozzle of the fuel injector of Figure 1 7; Figure 1 9 shows a cross-sectional view of a part of the fuel injector of Figure 1 7; Figures 20a) to 20d) are schematic illustrations of the operation of the fuel injector of Figures 1 7 to 1 9; Figures 21 a) to 21 d) show alternative forms of nozzle orifices of the fuel injector of Figures 1 7 to 20; Fig. 22 is a schematic representation of a second embodiment of the internal combustion engine with a fuel injection system according to the present invention; Fig. 23 is a schematic illustration of a fuel injector suitable for use with the motor of Fig. 22; Figure 24 is a schematic illustration of the fuel injector of Figure 23 and its arrangement with a surface of cams used to propel it; Fig. 25 is a schematic illustration of a second embodiment of the fuel injector suitable for use in the engine of Fig. 1 8 in place of the fuel injector illustrated in Fig. 1 8; and Figure 26 is an illustration of a modification of the cam arrangement of Figure 24. Detailed Description of the Invention Referring first to Figure 1, one can see in the figure an internal combustion engine 1 0 comprising a cylinder 1 1 in which a piston 1 2 moves reciprocally with the cylinder 1 1 and a piston 1 2 defining between them a combustion chamber 1 3. The piston 12 is connected by means of a connecting rod 1 4 to a crankshaft 1 5, which in turn is connected to a camshaft 1 6. A mechanism (not shown) such as a push-rod type mechanism, is used between the camshaft 1 6 and two conical seat valves 1 7 and 1 8 which are the engine's outlet and inlet valves. The camshaft 1 6 will drive the inlet valve 1 8 and the outlet valve 1 7 to open in a synchronized relation to the movement of the piston 1 2 in the cylinder 1 1 with recovery springs pushing the conical seat valves 1 7 and 1 8 back to their valve seats. The motor 10 is a simple motor, a single cylinder motor of for example a mower or other garden equipment. The engine 10 has a fuel injection system comprising a fuel injector 19 arranged to supply fuel to an inlet passage 20 upstream of the inlet valve 1 8. A throttle valve 21 is placed in the inlet passage 20 for throttling the flow of the charge air in the combustion chamber 1 3. A sensor is connected to the throttle valve 21 and feedback the signal by means of a line 22 to an electronic control unit 23, the signal indicates the position of rotation of throttle valve 21 and therefore the load of the engine. The ECU 23 also receives a timing signal by means of a line 24, the timing signal is generated by means of a camshaft sensor 25 (which could be replaced by means of a camshaft). Referring to the timing signal produced by the sensor 25 and the load signal produced by the sensor attached to the throttle valve 21, the ECU 23 generates a control signal which is conducted by means of the line 26 to the injector 1 9 and controls the operation of the injector 1 9. A first example of injector 1 9 is shown in figure 2. The injector 19 has a fuel inlet 30 in which a filter 31 is positioned to remove impurities from the fuel before it passes into the main body of the injector. The main body 32 of the injector has a cavity 33 in which a stack 34 of piezoelectric elements is located. The fuel introduced through the inlet 30 passes along the passageway 35 through the stack 34. A flexible diaphragm 36 is embedded in a free end of the stack 34 and the diaphragm 36 incorporates it into a one way valve 37 aligned with the passageway. 35 passing through the stack 34. A section 38 of the cavity 33 is defined by means of the flexible diaphragm 36 and leads from this section 38 there is a fuel outlet passage 39 which is opened and closed by means of a foil valve one way 40. Current below the sheet valve 40 are high voltage electrostatic charge electrodes 41 having openings to allow current flow. Downstream of the electrodes 31 that find a fuel outlet disc 42 having multiple fuel outlet openings defined in the; this disc 41 will also be charged to function as an electrode in such a way that the electrode 41 and the disc 42 jointly apply a charge to the fuel passing through the injector and this aids the atomization of the fuel. A simple gravity-fed fuel supply system (not shown) will transport the fuel from the fuel tank (not shown) to the fuel inlet 30, the fuel then being filtered through the filter 31. The fuel is then introduced and ejected from the fuel injector of Figure 2 by means of the expansion of the stack 34 of piezoelectric elements. When a voltage is applied to the piezoelectric elements of the stack 34 they expand and this expansion causes the stack 34 to grow in length and push the flexible diaphragm 35. When this happens the one-way valve 37 will close and the fuel in the section will be closed. 38 will be ejected from section 38 by means of flexible diagram 36, diaphragm 36 is flexed under the action of stacking 34. The one-way valve 40 will open to allow fuel to be expelled from section 38 and the ejected fuel will then pass through the holes in the charging electrode 41 and then through the holes in the fuel outlet disc 42 in the air inlet passage 20 (shown in Figure 1). The fuel passing through the electrode 41 and the disc 42 will receive an electrostatic charge and this electrostatic charge will assist atomization of the fuel leaving the holes of the fuel outlet disc 42. Once the voltage has been removed from the stack 34 of piezoelectric elements then the stack 34 will be reduced to its original length and the flexible diaphragm 36 which is elastic in nature, will move back to its original position, thus increasing the volume of the injector cavity section 38. This in turn will cause the one-way valve 40 to close to seal the fuel outlet section 38 while the one-way valve 37 will open to allow fuel to flow through the passage 35 to fill the cavity 38. The cavity 38 can then be charged with a fresh fuel charge ready for the next fuel injection in the air inlet passage 20. In Figure 2 the control line 26 can be seen electrically connected to the piezoelectric element stack 34 and also connected electrically to the high-voltage electrostatic charge electrode 41. The fuel injector of figure 2 operates as a positive displacement pump which in each operation of the injector supplies the same amount of fuel. The volume of fuel supplied by the injector is constant for each operation. This varies significantly between the injectors that function as on / off valves controlling the flow of fluid through them, the fluid supplied to them is supplied from a pressurized front. These injectors control the amount of fuel supplied by varying the opening time of the injector. There are no variations of the opening time with the injector of the present invention, rather it functions as a positive displacement pump and pumps a fixed volume of fuel in each operation. A second type of fuel injector suitable for operation as the injector 1 9 of figure 1 is shown in figure 3. The injector in each operation supplies a fixed amount of fuel and the injector itself operates as a pump to positively displace a fuel volume from there, the volume remains constant through each operation of the injector. Injector 19 is a simple positive displacement pump with a piston driven with a solenoid valve in a cylinder that works as a fixed displacement unit, with two one way check valves to ensure the correct flow path of fluid to and from from the injector. The injector acts both as a pumping unit and as a flow measurement unit. The volume of flow supplied by each pulse is a fixed geometric volume despite the differential pressure through the injector, making the injector insensitive to pressure fluctuations in the inlet passage 20 of the inlet manifold. The injector of Figure 2 has a fuel inlet passage 50 which will be connected to a fuel tank (not shown) to receive fuel under a simple gravity feed arrangement (not shown). A one-way valve 51 operated by a spring controls the flow of fuel out of the fuel cavity 52 to a fuel delivery line 54 through which the fuel can be supplied (directly or via a conduit to a nozzle of remote spraying) in the air inlet passage 20. A piston 55 is located slidably in the body of the injector. It is actuated by compressing the spring 56 and is surrounded by a solenoid 57. An end plate 58 is connected to the piston 55 and extends radially outwardly from the piston through an end face of the solenoid 57. The solenoid 57 is connected by means of from line 26 to ECU 23. Starting from a condition in which piston 44 is pushed to its lowest point when compressing spring 56 (this is the point at which fuel chamber 52 has its largest volume), the fuel chamber 52 will be primed with a fuel ready for injection. The energization of the solenoid 57 then acts to pull the plate 58 into contact or almost in contact with the solenoid 47. The piston 55 moves up against the force of the thrust spring 56 to reduce in volume the fuel chamber 52. This causes the positive displacement of the fuel from the fuel chamber 52, that the one-way valve 53 opens to allow the piston 55 to eject fuel from the fuel chamber 52 out of the fuel outlet 54. Once the solenoid 57 it is de-energized, then the thrust spring 56 will force the piston 55 downwardly and the plate 58 away from the solenoid 57. The downward movement of the piston 55 will cause the fuel chamber 52 to increase in volume in this manner and this will have the effect of closing the one-way valve 53 and opening the one-way valve 51. The movement of the piston 55 draws fuel from the fuel inlet 50 into the fuel chamber 52 to fully charge the fuel chamber 52 ready for the next fuel supply. The injector is constructed in such a way that the piston 55 has a fixed travel distance in each operation. The piston 55 moves between two end stops. Thus in each and every operation of the injector, the piston 55 is displaced a fixed amount of fuel in a fixed amount of fuel is expelled from the fuel outlet 54. The amount of fuel supplied by the injector is constant for each operation. A typical volume of fuel flow supplied by the injector is commonly between 0.1 μl and 1 μl, but typically less than 0.5 μl. The injector is typically capable of operating at frequencies from 300 Hz to more than 1 KHz, preferably between 1 KHz and 2 KHz. Such volume and frequent operation is suitable for many engine capacities in the market of small engines. The operating principle of the injector of Figure 3 is that of supplying a geometrically fixed volume of fluid for each activation pulse. Since motors of different capacities and power output will have different energy consumption rates, it is necessary to optimize the pulse volume that best suits the individual motor. In order to manufacture the injector of Figure 3 at high volumes and therefore at the lowest possible cost it is advantageous to have an injector size that fits a wide range of different sizes of engines. In order to achieve this, the movement of the injector piston can be easily adjusted during manufacturing by placing a wedge to give the desired pulse volume for the specific application of each injector. Figure 3 shows an injector without a wedge resulting in the maximum possible movement of the piston 55 in each pulse.

The same injector with a wedge 59 positioned as shown in figure 4. By means of the use of the wedge 59 the movement of the piston 55 is reduced, allowing the injector to be optimized for a smaller capacity motor. The volume of supply of the injector is still geometrically fixed and repeatable for each actuation during its operation. The key feature is that the displacement of the injector is always a constant geometric volume, to ensure the accuracy of the fuel supply when used in an engine. But the use of wedges allows the manufacture of high volumes at low cost with substantially identical injector units that can be easily configured to fit a wide range of engines in the last stage of manufacture. Figure 5 shows a fourth embodiment of the injector according to the present invention. As in the embodiments of Figures 3 and 4, the injector comprises a piston 400 which moves under the action of a thrust spring 401 and a solenoid 502. The piston 500 can slide in a fuel chamber 502. An inlet valve one way 504 allows the fuel to be extracted to the fuel chamber 503. A one way inlet valve 504 allows the fuel to be sucked into the fuel chamber 503 from a fuel inlet 505, but prevents the fuel from being ejected from fuel chamber 503 at fuel inlet 505. A one way outlet valve 506 allows fuel to be expelled from fuel chamber 503 to a fuel outlet 507 but prevents fuel from being sucked into the chamber of fuel 503 of the fuel outlet 507. Contrary to the embodiments of Figures 3 and 4, the injector of Figure 4 uses the spring 501 to force the piston 500 for torque to eject the fuel from the fuel chamber 503 to the fuel outlet 507. and use the solenoid 502 to move the piston to extract fuel in the fuel chamber 502 (which is the inverse of the embodiments of figure 3 and 4) . The piston 500 has an end plate 508 that extends radially outwardly from the piston 500 through an end face of the solenoid 502. The volume of the displaced fuel, the values of the spring, etc. they will be the same or similar to those described above. Figure 6 shows a modification of the embodiment of Figure 5 where a wedge 509 is provided in the combustion chamber 503 to limit the displacement of the piston 500 and thus adjust the amount of fuel dispensed in each operation of the injector. The wedge 509 has an opening that passes through it to allow communication between the fuel chamber 503 with a one way valve 506 and a fuel outlet 501.

As described above, the use of wedges allows a manufacturing process wherein substantially identical nozzle units with different volumes of fuel output are made by selecting wedges of suitable size. In Figures 4 and 6 the wedges 59, 509 shown are fixed to the injector housing, however a wedge could be fitted to any of the pistons 55, 500 instead of or in addition to the illustrated wedges 59, 509. Figure 7 shows an injector 700 with a piston 701 located in the center of a solenoid 702 and a rear iron 703. The rear iron 703 is designed to direct the flow around the solenoid turns. The piston 701 engages the rear iron 703 when the solenoid 702 is energized. A piston spring 704 pushes the piston 701 away from the rear iron 703 when the solenoid is de-energized. An inlet check valve 705 is located in a fuel passage that passes through the piston 701. The fuel passage allows the flow of fuel through the piston to a fuel chamber 706. The fuel is dispensed from a fuel chamber 706 to a fuel outlet 707 by an outlet check valve 708. In the fuel injector Fig. 7 The movement of the piston 701 advantageously aids the operation of the inlet check valve 705, as shown in Figures 8a) to d). Figure 8a shows the piston 701 in its lower stop position. The mass of the ball in the check valve 705 helps its own spring to close the check valve 705, thus sealing the fuel chamber 706. When the solenoid bore 702 is energized with an electric current, as shown in FIG. Figure 8b), the piston 701 is pulled upwards by the magnetic flux in the rear iron 703. In this movement the inertia of the ball of the inlet check valve brings the ball into firm contact with its housing, which ensures the sealing of the inlet valve 705 and thus ensures that all the fluid expelled from the fuel chamber 706 comes out through the outlet check valve 708. When the piston 701 reaches its upper position, as shown in Figures 8c) and the fuel pulse volume has been ejected, the piston 701 will stop rapidly at its extreme stop. The ball of the inlet check valve 705, however, will continue upward due to its own momentum and will open the outlet check valve 705. At this time the solenoid 702 is de-energized and the piston spring 704 pulls on the piston 701 down. As shown in Figure 8d), the piston 701 moves downwardly driven by its spring. The ball of the check inlet valve 705 is left behind due to the inertia of its mass as well as the force of the fuel flow and in this condition it will allow the fluid to flow promptly and replenish the fuel chamber 706 while the piston 701 continues its downward movement. When the piston 701 reaches its lower stop it will be stopped again quickly and the ball of the check in valve 705 will be brought into contact with its housing again due to its momentum, as shown in Fig. 8a). In this way, the opening and closing of the check in valve 705 is assisted by the movement of the piston 701. This allows the injector to be driven at a higher frequency than would normally be possible. Figure 9 shows a more detailed sectioned drawing of the injector of Figures 7 and 8a) to 8d). The inlet check valve 705 can be seen comprising a ball 71 0 and a spring 71 1. The spring value of the spring 71 1 of the check valve 51 is typically chosen in the range of 0.4 N / mm to 1.75 N / mm to allow lifting of the retention ball from its housing during the inlet movement, the displacement of the piston is typically 50 to 150, in this case 1 00 μm. The check in valve 51 is shown in Figure 1 1 comprising the ball 71 0 and the spring 71 1. With the placement of the inlet check valve in a fuel passage in the piston, it is possible to work without a check valve spring, as illustrated in figures 1 0a) to 1 0d) and Figure 1 2. The the inlet check valve 7000 comprises (see Figure 1 2) a movable ball 7001 in a cage 7002. The cage 7002 allows the flow of fuel, but keeps the ball 7001 trapped in position. The function of the valve 7000 is described exactly as the valve 705, but the inertia of the mass of the ball 7001 is relied upon as the only means of opening and closing the valve 7000. This is visible in figures 10a) to 1 0d), wherein the movement of the ball and the piston are indicated by arrows, as well as the direction of fluid flow. In FIG. 1 0a) the movement of the ball 7001 forces the closure of the valve. In Fig. 10b) the mass inertia of the ball 7001 lifts the ball out of its housing while the piston moves down (the pressure differential along the valve also plays a role). In Figure 10d) it can be seen that the cage 7002 prevents the ball 7001 from moving too far from its housing while the piston moves downwards. Using A valve without spring reduces the cost and time of assembly. A disc could be used in place of the ball and this is illustrated in Figure 13 where the disc is movable in cage 701 1 (this valve operates in the manner described above for valve 7000). The use of a disc can reduce the volume of fluid trapped in the fluid passage through the piston on the valve and make the arrangement less susceptible to gas trapping. The control of injectors of the present invention is quite different from the control of the injectors of the prior art, as will now be illustrated in Figures 1 4, 1 5 and 16a) to 1 6d). In Figure 14 a graphic illustration of a control signal used to control a prior art injector can be seen. The operating mode used is called pulse width modulation control. In the solid lines you can see a pulse of a chosen width and this corresponds to the duration of the opening of a traditional fuel injector. The dotted lines show other larger pulse widths, in this case longer opening durations of traditional injectors of the prior art. With a fixed applied pressure, the pulse width control provides accurate control of the amount of fuel provided by the fuel injector. Turning to FIG. 1 5, it graphically illustrates the control signal generated by the ECU 23 to control the fuel injector 1 9 in the present invention. Instead of pulse width modulation, a form of control called pulse count injection is used. You can see six different pulses in solid lines. These are the pulses for a single cycle of engine operation, in this case the delivery of a single fuel charge for a single combustion event in the combustion chamber 1 3. Each pulse represents an operation of the injector 1 9. As explained previously, since the injector 1 9 in each operation delivers a fixed amount of fuel, the total amount of fuel for combustion is controlled, controlling the number of injector operations for a particular engine operating cycle. In the case illustrated with solid lines, the injector 1 9 is operated six times to fix the amount provided to the combustion chamber 1 3. The first operation of the injector 1 9 will take place while the inlet valve 1 8 is closed but can be that the valve is open or at least has begun to open when the last operation of the injector 19 occurs. In Figure 1-5 the pulses of dotted lines show that a greater amount of fuel can be delivered in the operating cycle when operating the injector a greater number of times. Figure 1 5 illustrates a total pulse count of 10 pulses with a total amount of fuel being provided by the injector in each operation. More details are given in Figures 16a) to 1 6e). Figure 16a) shows the camshaft or crankshaft signal received on line 24 by the ECU 23. The pulses illustrated in the signal give an indication of the rotational position of the camshaft or crankshaft. It will be seen that the ECU 23 timer its own pulses in the control signal it generates so that they are synchronized with the pulses of the timing signal shown in Fig. 1 6a). In fact, it is the pulses in the timing signal of Fig. 1 6a) that generate the ECU 23 to generate its own control pulses, as shown in Figs. 1 6b) to 1 6e). Alternatively the pulses of the timing signal can be generated internally in the ECU 23, with only one timing pulse motor cycle of a camshaft or crankshaft sensor. Figure 16b) shows a full load operation. Therefore, in each motor cycle (one motor cycle takes place between the dashed lines in the figure) the ECU generates a control signal shown in Figure 16b) comprising thirteen pulses that operate the injector 1 9 thirteen times . This represents the maximum amount of fuel that can be provided for combustion in the combustion chamber 1 3. Figure 1 6c) shows the control signal generated in each engine cycle for partial load operation. In this case, the control signal in each cycle comprises seven pulses that operate the injector 1 9 seven times in each motor cycle. Thus, the amount of fuel provided in each engine cycle is 7713 of the total fuel amount that is provided in the fully loaded operation. Figure 16d) shows the control signal generated by the ECU through the inactive operation, in this case the time when the least amount of fuel is provided in each engine cycle. Figure 1 6d) shows that the injector 1 9 is operated only 4 times in each engine cycle. Finally, Figure 1 6e) shows an exceptional condition of starting the engine where a rich mixture of fuel and air is provided inside the combustion chamber 1 3 to allow the engine to start. The total fuel delivered is seventeen times the fixed amount that the injector delivers in each operation. It will be appreciated that the engine described above eliminates the need for a separate fuel pump and a pressure regulator and dramatically simplifies the function of the ECU. The injection system comprises a simple control system that counts the desired number of fuel impulses towards the engine for its correct operation. Although this does not provide the degree of control possible with the prior art (in this case the total volume of fuel delivered can not be varied continuously within a range, but only in fixed amounts or fixed intervals) this would be sufficient for a simple engine such as that of a mower.

Putting it another way, the possible control with the pulse count injection gives a coarser control of the amount of fuel provided to the engine, but this will be enough for the engines (simple involved.) As described above, the fuel provided from the injector can be passed to a simple flat hole or nozzle (see Figure 2) or can be passed through an atomizing device such as a pressure spraying nozzle (described later with reference to the Figures 1 7, 1 8, 1 9, 20 a) to 20 d) and 21 a-21 d)) or an electrostatic charging unit (shown in Figure 2). The injector (or pulse unit) can be coupled to the atomization unit located at another point of the engine with a certain distance (in this case the mode of Figure 3 can have a fuel outlet leading to a dispensing nozzle with some distance of the injectors shown). The volume of fuel delivered by the fuel injector will depend in some way on the size of the engine and the range of engine operating conditions. Typically, an injector will deliver between 0.05mm3 and 0.08mm3 per pulse. If we assume the range of 0.01 mm3 to 0.5mm3 per pulse then typically the total volume delivered in each cycle will be between 0.5 and 1 0.0 mm3. If this is the case then the number of pulses required to correct motor operation will vary from five to ten pulses per motor cycle for motor inactivity and twenty to fifty pulses per cycle for a full load operation. Since the injector controls the amount of fuel delivered by itself, there is no need for a controlled supply pressure and this means that the fuel can be supplied directly to the injector by means of a gravity feed system without causing problems for the pressure variation due to the difference of the fuel head when the fuel level drops. Alternatively, a simple low pressure pump, such as those frequently used with carburetors, could be used. The only requirement is that sufficient fuel be supplied to the injector so that it can be recharged for the next pulse. The total amount of fuel supplied to the engine in each cycle (every two movements in a two-stroke engine or every four movements in a four-stroke engine) is determined as a multiple of the volume of fuel supplied in each operation of the injector and the number of times the injector is operated in a cycle. The engine management system can be constructed simply to supply a different number of pulses in its control signal depending on the required load demand of the engine, as measured with the sensor 21. A very simple electrical control unit can therefore be constructed of only a few integrated circuit chips that compare the position of the choke as measured by the sensor 21 (i.e. a choke position potentiometer) with a look-up table that gives the number of pulses required for that throttle position and with the ECU generating pulses triggered by the timing signal of line 24 and counting the number of pulses until the correct number of pulses is reached is achieved. Then the pulse injector shuts off until the next motor cycle. Turning to Figure 17, a choke body 202 of an internal combustion engine is shown. The choke body 202 includes an inlet passage portion 200 of the inlet passage 20 of Figure 1. The inlet passage part 200 communicates at one end 204 with the combustion chamber of the engine 1 3 by means of the inlet valve 1 8, and at the other end 206 with atmospheric air, typically by means of an air filter ( not shown). Within the inlet passage portion 200 is located a throttle valve 21 and downstream of the throttle valve 21, between the throttle valve 21 and the inlet valve 18 is the fuel injector 1 9, of the type previously illustrated in Figures 3 to 1 3. In the arrangement of Figure 1 7 the fuel supplied from the fuel chamber 52 is supplied to the fuel outlet 21 4 comprising in the embodiment of figure 1 3 a mixing chamber 21 8 and a spray nozzle 21 4. To assist in the production of a mixture of fuel and air that burns rapidly when ignite in the combustion chamber, the fuel must be effectively mixed with the charging air. Conventional combustion carburetors and injectors achieve this by having a number of holes in the end of the nozzle of the injector to form a fine spray of fuel from the nozzle to the charging air. The atomization nozzle 214 of the present invention is a sonic nozzle (also known in the art as a critical flow venturi, or critical flow nozzle). The atomization nozzle can also be an air trigger nozzle. Sonic nozzles are often used as flow standards by providing a constant volumetric flow rate, provided that the pressure differential across them exceeds a predetermined threshold value. A schematic diagram of the sonic nozzle is shown in Figure 1. The nozzle comprises a venturi 350, whose internal dimensions shrink to provide a throat. The rising fluid 352 of the venturi throat is at a higher pressure than the downstream 354 of the venturi throat. The fluid that flows into the nozzle is accelerated in the shrunken throat region. The velocity of the fluid in the throat approaches the speed of sound. Once this condition is realized the flow rate through the sonic nozzle will remain constant even if the downward pressure varies significantly, provided of course, that the pressure differential across the nozzle continues over the threshold value. This achieves a constant fuel flow rate towards the cargo air. It should be noted that a sonic nozzle will provide a constant flow no matter how abrupt the downward pressure change provided the downward pressure provided that the downstream pressure remains at less than about 85-90% of the upstream pressure. In the present invention the passage of fuel through the sonic nozzle 21 4 helps to disperse the fuel within the air charge. In fact, since the velocity of the fuel passing through the throat 302 approaches the speed of sound, the nozzle 21 4 acts as a highly effective atomizer distributing the liquid fuel in a cloud of minute particles. Generally, the finer the spray that is distributed in the air charge, the better the combustion process will be. Although the exact operation of sonic nozzles in fuel atomization is not well understood, it is believed that the passage of liquid fluid by shock waves in the high velocity region of the sonic nozzle produces very high tearing forces in the liquid- bubbles of surface and cavitation within the liquid, with both processes leading to a very fine atomization and a dispersion of the fuel in the cargo air. The mixing chamber 218 is located between the retention outlet valve 53 and the nozzle 226. As can be seen in Figure 1 7, and in the enlarged view of Figure 1 9, the throttle body 202 also comprises a passageway. bypass 240. This consists of a passage that communicates with both the mixing chamber and a region where the air is at atmospheric pressure. The fuel supplied by the injector 1 9 passes through the mixing chamber 21 8 and continues through the sonic nozzle 226. The low pressure in the inlet passage 200 also pulls air through the air bypass 240. Thus the air flows through the air. the air bypass pipe 240 and guiding the fuel supplied by the injector 1 9 to the mixing chamber 21 8. The air in the air bypass 240 is at a higher pressure than the air in the inlet passage 200, and therefore when the fuel is supplied from the nozzle 214 it is carried in an air flow from the passage 240 through the sonic nozzle 214 to the inlet passage 200. This causes the supplied fuel to be atomized. Figures 20a9 to 20d) show the operation of the sonic air assisted atomizer for a port fuel injector, by the engine cycle for two different load conditions of the engine. Injector 1 9 supplies the fuel and controls the amount of fuel. The movement of air in the inlet port generates the atomization effect. This allows each process to be fully optimized to achieve maximum effect with minimal energy. In Figures 20a) to 20c) the fuel is introduced into the mixing chamber 21 8 during the period of the engine cycle when the inlet valve of the engine 18 is closed. In these conditions (regardless of the load of the motor) there is very little movement of air and thus the fuel supplied in a period of time by the motor cycle will accumulate in this chamber. When the inlet valve 1 8 is opened, air is sucked through the inlet port into the combustion chamber 13. In a partial load condition shown in Figures 20a) and 20b) the choke 21 is partially closed and the flow of air will generate a pressure difference across the throttle 25. In a full load condition (fully open throttle) shown in Figures 20c) and 20d) the air velocity at this time creates a pressure drop in the throat 302 of the Venturi With a volume of fuel accumulated in the mixing chamber the flow of air through the bypass passage 240 begins to cause the effervescence of the fuel and as the air flow and the introduced fuel increase in speed in the sonic nozzle 214 (due to the reduction in the cross-sectional area) high tearing forces are created which lead to excellent atomization of the fuel as it is blown at the port of entry. This process not only generates a well atomized fuel spray but has the advantage that its timing is coincident with the inlet valve 18 being opened so that the fuel is admitted in the combustion chamber 1 3 and does not settle on the wall from the port of entry. This timing effect also allows the rest of the engine cycle to measure the fuel in the mixing chamber 21 8, allowing lower pressure injectors to be used without their inherent lack of atomization causing problems due to low atomized fuel. In this way, very well atomized fuel is supplied in the best time of the engine with a minimum of energy use. Improved fuel atomization at the port of entry improves fuel mixing and therefore improves the combustion process resulting in lower emissions and lower fuel consumption as well as better starting for small engines. The air bypass 240 is not limited to supplying air but could alternatively be connected to a gas source to provide an alternative gas to assist atomization or combustion. An example of another gas that could be used is the engine exhaust gas (this is exhaust gas recirculation). The sonic nozzle 214 may have holes or different shapes such as those shown in Figures 1 6a) to 1 6d). The hole of a standard sonic nozzle when a cross section is taken perpendicular to the direction of flow, is circular as shown in Figure 1 6a. Alternative forms of the nozzle orifices comprise a linearly extending orifice as shown in Fig. 1 6b, a cruciform shapes as shown in Fig. 1cc) or alternatively a grouping of small circular holes as shown in Fig. 16d. . Figure 22 shows another embodiment of the engine according to the present invention, the motor has a mechanically energized injector that is electrically controlled, and not an electrically energized injector as previously described. Figure 22 shows an internal combustion engine comprising a cylinder 81 in which it reciprocates a piston 82 with the cylinder 81 and the piston 82 defining between them a combustion chamber 83. The piston 82 is connected when connecting a piston 82. bar 84 to the crankshaft 84 which in turn is connected to the camshaft (not shown) which has cams which by their action operate two conical seating valves 87 and 88 which are the outlet and inlet valves of the engine. Those valves open and close in a temporal relation to the piston 82 and the cylinder 81. The recoil springs (not shown) will be provided to push the tapered seat valves 87 and 88 into their valve seats. The motor 80 is a simple motor, a single cylinder motor of for example a mower or other garden equipment. The engine 80 has a fuel injection system comprising a fuel injector 90 arranged to supply fuel to an inlet passage 89 upstream of the inlet valve 88. A throttle valve 91 is placed in the inlet passage 89 to throttle the flow of charge air in the combustion chamber 83. A sensor is connected to the throttle valve 91 which is supplied as an electrical signal to an electronic control unit 92. The fuel injection system of Figure 22 comprises a cam surface 92 provided on a circumferential surface of a wheel 94 mounted and rotating with the crankshaft 85. A fuel injector 96 is driven by means of the cam surface 93 and is shown in greater detail in Figure 23.

In Figure 23 it can be seen that the fuel injector 96 comprises a fuel inlet 97 which receives the fuel feed from a fuel tank (not shown) by means of a gravity feed system (not shown). The fuel can pass from the fuel inlet 97 to the fuel chamber 98 with the flow of the fuel controlled by means of a one-way valve loaded with spring. A second one-way valve 1 00 loaded with a spring controls the flow of fuel from outside the fuel chamber 90 to the fuel outlet 101. The fuel outlet 101 is connected by means of a fuel line 1 02 (seen in Figure 22) to be supplied to the supply nozzle and to the atomizer 90. A piston 1 02 is slidably mounted in a housing 1 03 of the injector 96 and is slidable in the fuel chamber 98. The piston 1 02 has a cam follower 1 03 which is a rotary fan mounted rotatably on one end of the piston 1 02. The roller follower 1 03 will be coupled with and will follow the cam surface 93 (see figure 22). The piston 102 and therefore the roller follower 1 03 are pushed to engage with the cam surface 93 by means of a thrust spring 1 04 acting between the body 1 03 and the injector and a flange 1 05 provided to extend radially out of the piston 1 02. Also in the injector 96 there is a control solenoid 106 which is electrically controlled by means of a signal provided on a line 1007 along which the control signals pass from the motor control unit 92. The solenoid 1 06 may act on a transfer pivot 1 07 consisting of a bar 1 1 3 extending through the solenoid 1 06 and a disc 1 09 extending radially outwardly from the bar 1 1 3 on one end of the control solenoid 1 06. During the operation of the injector (and starting from a condition in which the piston 1 02 occupies a position in which the fuel chamber 98 has its largest volume and assuming that the fuel chamber 98 is fully charged with a fresh fuel charge), the piston 1 02 will be pushed to the chamber 98 under the action of the cam surface 93. The piston 1 02 will then displace the fuel from the chamber 98 that will flow out of the fuel outlet 101, the one-way valve 1 001 it is opened to allow the supply of fuel from the fuel chamber 98, while the one way valve 99 seals the fuel inlet 97 from the fuel chamber 98, while the one way valve 99 seals the fuel inlet 97 of the fuel chamber 98. The fuel expelled from the fuel chamber 98 will pass along the fuel line 1 02 to the supply nozzle 90, to be supplied as a rhodium in the air inlet passage 89. Subsequently , the piston 1 02 (following the profile of the cam surface 93 and under the action of the thrust spring 1 04) will move to increase in volume the fuel chamber 98. This will have the effect of closing the one-way valve 100 while the one-way valve 99 is opened. The fuel will then be withdrawn into the fuel chamber 98 from the fuel inlet 97 until a maximum volume of fuel is obtained, then s of which the process will start again. In Figure 24 the injector 96 can be seen interacting with the cam surface 93 and it can be clearly seen that the cam surface 93 comprises pulse lobes such as 1 1 0 separated by 1 1 1 base circle regions, the pulse lobes typically have a ridge 0.1 to 0.5 mm greater in radius than the base circle. It is seen in FIG. 10 that the wheel 94 has a total of twenty pulse lobes and also a section 12 with a constant radius. When the follower of roller 1 03 couples the section 1 1 2 and then the pulse injector 1 1 6 is deactivated. If the control solenoid 1 07 remains off during the entire motor cycle then each of the pulse lobes (for example 1 1 0) on the cam surface will result in a quantity of fuel being supplied from the injector pulse 96. The injector 96 will supply twenty separate pulses of fuel for each complete rotation of the wheel 94. It should be understood that each pulse lobe 1 01 will have a height relative to the base circle that is identical to all other pulse lobes, so that the piston 1 02 in each operation will move a fixed amount in such a way that the amount of fuel supplied by the injector 96 is the same for each and every operation of the injector 96, this is for each and every supply of fuel from the injector 96. The operation of the injector 96 twenty times for each rotation of the wheel 94 represents the supply of the maximum possible volume of fuel to the engine in each cycle of operation using such condition for example when starting the engine. The control solenoid 107 allows control of the injector 96. When the solenoid 1 06 is energized, then the pin 1 08 will engage with the one way valve 99 and force it to open and remain open. When the one-way valve 99 is opened then the movement of the piston only results in it being sucked into the fuel chamber 98 of the fuel inlet 97 and then the ejection of the fuel from the chamber 98 back to the inlet of the inlet. fuel 97. Fuel is not ejected from chamber 98 by means of the one-way valve 100. Thus the ECU can control the operation of injector 96 and can control how many pulses as fuel pulses are supplied by injector 96 and can control when fuel pulses are supplied by the injector 96 and consequently the total amount of fuel supplied in each engine cycle (every two movements in a two-stroke engine or every four movements in a four-stroke engine). In Figure 25, an injector 1 50 can be observed which could be used in the motor of Figure 7 instead of the injector 96 illustrated in the figure. The injector 1 50 comprises an inlet for fuel 1 451 which receives the fuel fed from a fuel tank (not shown) by means of a gravity feed system (not shown). The fuel can pass from the fuel inlet 1 51 to the fuel chamber 1 52 with the fuel flow controlled by a first one-way valve loaded by spring 1 53. A second one-way valve charged by spring 1 57 controls the flow of the fuel out of the fuel chamber 1 52 to a fuel outlet 1 53. The fuel outlet 1 54 will be connected by means of a fuel line 1 20 of figure 7 to the supply nozzle and to the atomizer . An elastic diaphragm displacement 1 55 seals the fuel chamber 1 52. The diaphragm 1 55 is provided with a follower contact pad 1 56. The contact pad 1 56 will contact and follow a cam surface (not shown). The contact pad 1 56 is forced into contact with the surface of the cam by the elastic diaphragm 1 55. The surface of the cam will vary in nature under the control of ECU 92 with the intention of producing a variable number of impulses to the contact pad 1 56. This will be achieved, for example, by mounting a second control wheel 95 along the cam wheel 94 which will rotate with the cam wheel 94, but also rotatable with respect to the cam wheel under the control of ECU. The cam wheel arrangement 94 and the control wheel 95 is shown in Figure 26. The control wheel 95 has a first sector 95a with a periphery of contact radius equal to the radial distance to the peak of each lobe 1 of the contact wheel 94 and a second sector 95b with a periphery with a constant radius equal to the radial distance to the bottom of each circular base region 1 1 1 of each cam wheel 1 1 1. At one end, the second sector 95b of the control wheel 95 will be aligned with all the lobes and circular base sections of the cam wheel 94 and will be active in the displacement of the diaphragm 1 55. Thus, as the control wheel 95 and the cam wheel 94 have a relative rotation with each other, the first sector 95a of the control wheel is aligned with some of the lobes 1 10 and the circular base sections 1 1 1 and "disables" them since the largest radial height of the control wheel 95"removes" the portions of the circle from the base 1 1 1 of the cam wheel 94. In the operation of the injector 1 50 (and started from a position in which the diaphragm 1 55 occupies a position in which the fuel chamber 1 52 has its largest volume and assuming that the fuel chamber 1 52 is located fully loaded with fresh fuel) the diaphragm will flex under the action of cam 1 1 0 to reduce in volume the fuel chamber 1 52 and in such a way that it displaces fuel from the fuel chamber 1 52 through the fuel outlet 1 54, the one-way valve 1 57 will open allowing the fuel to be dispensed from the fuel chamber 1 52, while the one-way valve 1 53 seals the fuel inlet 1 51 from the fuel chamber 1 52. The fuel is forced to exit through the fuel chamber 1 52 which will pass through the fuel pipe 120 and supply it to the nozzle 90 as an aerosol together with the passage of the inlet air. Subsequently, the diaphragm 1 55 (following the profile of the cam surface and due to its own elasticity), will flex by increasing the volume of the fuel chamber 1 52. This will cause the closing effect of the one-way valve 1 57 while the opening of the one-way valve 1 53. The fuel will enter the fuel chamber 1 52 from the fuel line 1 51 at a maximum volume to be reached, with which the process will start again. In each cycle of operation of the machine the diaphragm 1 55 will flex to expel fuel from the fuel chamber 1 52 for each cam lobe operable in each cycle, the operable number of cam lobes starts selected by the ECU, for example, by the rotation of the aforementioned control wheel relative to the cam wheel. As in the machine of Figure 1, the machine of Figure 22 does not require a high pressure pump to pressurize the fuel supply or pressure regulator to control the pressure of the supplied fuel. The machine does not require a sophisticated ECU to control the operation of a fuel injector. Therefore, the ECU can be constructed from simple integrated circuit chips, which together select the appropriate number of pulses for a given motor load (recorded by the motor load sensor91) and then count the number of pulses supplied in a motor cycle before deactivating the injector. With the motor of Figure 22 it may be possible to arrange a mechanical control for the injector 96 by means of some links between the choke and the injector 96. In all the embodiments of the engine described above, only a single injector has been used for each cylinder of the engine. engine that is working. However, the applicant provides that each working cylinder can be provided with a plurality of injectors. This could have two advantages, first in order to supply a given amount of fuel in each engine cycle, the number of operations of each individual injector would be reduced and this could have practical benefits since each injector would not need to operate at such a speed high during use. Second, if the injectors for a particular working cylinder were built in such a way as to supply a different amount of fuel to each other, then the engine management system could control the operation of both in a way that provides "finer" control "of the amount of fuel supplied in each work cycle. For example, if an engine with a single injector is supplied that injects 0.1 mm3 per pulse, then the total fuel injected per engine cycle will have to be a multiple of 0.1 mm3, that is 0.2 mm3, 0.3 mm3 and up to 0.1 mm3. However, if an angle is provided with two injectors, one of which injects a pulse of 0.1 mm3 and the other that injects a pulse of 0.05 mm3 then the engine will be able to supply in each motor cycle a total amount of fuel that could be 0.05 mm3, 0.1 mm3, 0.1 5 mm3, 0.2 mm3, etc. This is achieved with a smaller number of injector operations than would be necessary if the work cylinder only had one injector capable of a 0.05 mm3 pulse.

Claims

CLAIMS 1. An internal combustion engine comprising: a variable volume combustion chamber; an air intake system to supply air to the combustion chamber; an exhaust system for expelling the burned gas from the combustion chamber to the atmosphere, and a fuel injection system for supplying fuel in the charge air for combustion in the combustion chamber; wherein the injection system comprises: a fuel injector that functions as a positive displacement pump and supplies the amount of fuel that is set for each and every operation of the injector; and a controller that controls the operation of the fuel injector; wherein: in each of at least a majority of engine cycles the fuel injector is operated on a plurality of occasions by means of the controller; in response to an increase in engine speed and / or controller load the amount of fuel supplied per engine cycle increases as the number of times the fuel injector is operated per engine cycle increases; and in response to the reduction of engine speed and / or load the controller reduces the amount of fuel supplied per engine cycle by reducing in number the occasions that the fuel injector is operated per engine cycle.
2. An internal combustion engine comprising: a variable volume combustion chamber; an air intake system to supply air to the combustion chamber; an exhaust system to expel the burned gas from the combustion chamber to the atmosphere; and a fuel injection system for supplying fuel to the air for combustion to take place with it in the combustion chamber, wherein the fuel injection system comprises: a plurality of fuel injectors of which each operates as a positive displacement pump and supplies a quantity of fuel that is fixed for each and every operation of the injector; at least a first fuel injector of the plurality of fuel injectors that supplies a fixed amount of fuel different from a second fixed quantity supplied by a second fuel injector of the plurality of fuel injectors; and a controller that controls the operation of each of the plurality of fuel injectors; wherein: in each one of the at least a majority of engine cycles of the fuel injectors are operated on a plurality of occasions by the controller; in response to the increase in engine speed and / or engine load the amount of fuel increases for the engine cycle as the number of times the fuel injectors are operated by engine cycles increases; and in response to the reduction of the engine speed and / or the load of the controller the fuel supplied per engine cycle is reduced in quantity by reducing the number of occasions that the fuel injectors are operated by engine cycles.
3. An internal combustion engine according to claim 1, wherein the fuel injector uses electric power to supply the fuel therefrom and the controller is an electronic controller that produces a pulsed control signal to control the / each fuel injector , each pulse causes the / each fuel injector to supply the fuel and the electronic controller varies the number of pulses per engine cycle to vary the amount of fuel supplied.
An internal combustion engine according to claim 3, wherein the / each fuel injector comprises a stack of piezoelectric elements which, when increasing in length, eject the fuel out of the fuel injector.
An internal combustion engine according to claim 3, in which the / each fuel injector has an electric coil for expelling the fuel out of the fuel chamber.
6. An internal combustion engine according to claim 4 or 5, in which the / each fuel injector has a housing in which it is formed in the fuel chamber, from which the fuel of the chamber is expelled from / of each fuel injector, the / each fuel injector has a fuel input to admit the fuel into the fuel chamber and a fuel outlet by means of which the fuel is ejected from the / each fuel injector, the / each fuel injector also has a first one way valve that allows that fuel flows into the fuel chamber from the fuel inlet while preventing the flow of fuel from the fuel chamber back to the fuel inlet and the / each fuel injector also has a second one hour valve that Allows fuel to flow out of the fuel chamber to the fuel outlet, preventing the flow of fuel back into the fuel chamber. ombustible from the fuel outlet.
An internal combustion engine according to any one of claims 3 to 6 in which a sensor is provided for monitoring the motor load and providing the electronic controller with a signal indicating the load of the motor, the electronic controller calculated as Many pulses to produce in each engine cycle referred to the load of the engine.
An internal combustion engine according to claim 7, in which a sensor is associated with a crankshaft or a camshaft of the engine and produces a timing signal related to the rotation of the crankshaft or camshaft, signal of timing that is used by the electronic controller to trigger the pulses thus generated.
9. An internal combustion engine comprising: a variable volume combustion chamber; an air intake system to supply charge air to the combustion chamber; an exhaust system to expel burned gas from the combustion chamber into the atmosphere; and a fuel injection system for supplying the fuel in the cargo air to be burned with it in the combustion chamber; wherein the fuel injection system comprises: a fuel injector that functions as a positive displacement pump and supplies a quantity of fuel that is fixed for each and every operation of the injector; and a controller that controls the operation of each of the plurality of fuel injectors: wherein: or in each of the at least a majority of engine cycles of the fuel injectors are operated on a plurality of occasions by the controller; in response to the increase in engine speed and / or engine load the amount of fuel increases for the engine cycle as the number of times the fuel injectors are operated by engine cycles increases; and in response to the reduction of the engine speed and / or the load of the controller the fuel supplied per engine cycle is reduced in quantity by reducing the number of occasions that the fuel injectors are operated by engine cycles; and the fuel injector comprises: a housing in which a fuel chamber is formed; an electric coil; and a piston that slides axially in a hole in the housing under the action of the electric coil to eject the fuel out of the fuel chamber, the piston slides between two end stops which ensure that the piston has a travel distance fixed in each operation.
10. An internal combustion engine comprising; a combustion chamber with variable volume; an air intake system to supply charge air to the combustion chamber; an exhaust system to expel burned gas from the combustion chamber into the atmosphere; and a fuel injection system for supplying the fuel in the cargo air to be burned with it in the combustion chamber; wherein the fuel injection system comprises: a plurality of fuel injectors of which each operates as a positive displacement pump and supplies a quantity of fuel that is fixed for each and every operation of the injector, at least one first injector of fuel of the plurality of fuel injectors supplying a fixed amount of fuel different from a second fixed quantity supplied by a second fuel injector of the plurality of fuel injectors; a controller that controls the operation of each of the plurality of fuel injectors: wherein: in each of the at least a majority of engine cycles of the fuel injectors are operated on a plurality of occasions by the controller; in response to the increase in engine speed and / or engine load the amount of fuel increases for the engine cycle as the number of times the fuel injectors are operated by engine cycles increases; in response to the reduction of the engine speed and / or the load of the controller the fuel supplied per engine cycle is reduced in quantity by reducing the number of occasions that the fuel injectors are operated by engine cycles; and each fuel injector comprises: a housing in which a fuel chamber is formed; an electric coil; and a piston that slides axially in a hole in the housing under the action of the electric coil to eject the fuel out of the fuel chamber, the piston slides between two end stops which ensure that the piston has a travel distance fixed in each operation. eleven .
An internal combustion engine according to claim 9 or 10, in which the / each fuel injector comprises a thrust spring acting on the piston.
12. An internal combustion engine according to claim 1, wherein the electric coil surrounds the piston.
An internal combustion engine according to claim 12, in which an end plate is connected to the piston and extends outwardly of the piston through an end face of the electric coil.
14. An internal combustion engine according to any one of claims 9 to 13 in which the / each fuel injector has an inlet for fuel, an outlet for fuel, a one-way inlet valve that allows the fuel is sucked into the fuel chamber from the fuel inlet while preventing the fuel from being expelled from the fuel chamber to the fuel inlet and the one way outlet valve that allows fuel to be expelled from the chamber of fuel at the outlet of the chamber while preventing the fuel from being sucked into the fuel chamber from the fuel outlet.
An internal combustion engine according to claim 1 in which the one-way inlet valve is a spring-operated valve.
16. An internal combustion engine according to claim 1 4 or 1 5 in which the one-way inlet valve is a spring-loaded valve.
An internal combustion engine according to any one of claims 14 to 16 in which the one-way inlet valve is provided in an inlet passage in the housing.
An internal combustion engine according to any one of claims 14 to 16 in which the piston is provided with a fuel inlet passage through which the fuel is supplied to the fuel chamber and the valve One-way inlet is provided in the fuel inlet passage of the piston, the one-way inlet valve has a movable valve member sealing against a seat and the one-way inlet valve is positioned in such a way that the moment of the valve member arising from the movement of the piston helps both to open and close the one-way inlet valve.
19. An internal combustion engine according to claim 18, wherein the valve member is a ball.
20. An internal combustion engine according to claim 18, wherein the valve member is a disk. twenty-one .
An internal combustion engine according to any one of claims 9 to 20 in which a piston spring pushes the piston to engage with one of the end stops and the solenoid acts to slide the piston in engagement with the other stop against an thrust force applied by the piston spring.
22. An internal combustion engine according to claim 21, wherein the piston spring pushes the piston to eject the fuel from the fuel chamber.
23. An internal combustion engine according to claim 21, wherein the piston spring pushes the piston to suck fuel from the fuel chamber.
24. An internal combustion engine according to any one of claims 9 to 23 having a wedge forming one of the end stops.
25. An internal combustion engine according to any one of claims 9 to 24 having a wedge attached to the piston.
26. A manufacturing method for an internal combustion engine according to any one of claims 24 or 25 which consists in selecting a wedge sized to provide a selected fixed moving distance.
27. A method of manufacturing a plurality of internal combustion engines according to one of claims 9 to 25 wherein the engines are provided with fuel injectors that supply different fixed amounts of fuel by setting different distances of movement of the engines. pistons of the engines injectors when using wedges to fix the travel distances of the piston in some and not using wedges in others and selecting wedges of different sizes for different engines to give different piston travel distances.
28. An internal combustion engine according to claim 1 or 2, in which the / each fuel injector is driven mechanically by means of a cam surface, the / each fuel injector has a piston driven by means of a thrust spring and the piston is displaceable by means of the cam surface to eject the fuel out of the fuel chamber, the cam surface comprises a plurality of cam lobes each of which can drive the piston during each engine cycle and the controller controls how many cam lobes in each engine cycle cause the piston to eject the fuel out of the fuel injector.
29. An internal combustion engine according to claim 28, wherein the / each fuel injector has a body having a fuel chamber and a fuel outlet through which the fuel is expelled out of the fuel. chamber for fuel by means of the piston, the / each fuel injector has a fuel inlet through which fuel is introduced into the fuel chamber, the / each fuel injector also has a one-way inlet valve that serves to allow fuel to flow into the fuel chamber from the fuel inlet while preventing the flow of fuel back from the fuel chamber to the fuel inlet and a one way outlet valve that serves to allow the fuel flow out of the combustion chamber towards the fuel outlet preventing at the same time the flow back to the combustion chamber ible from the fuel outlet.
An internal combustion engine according to claim 28, in which the one-way inlet valve can be disabled by the controller and when it is disabled allows the flow of fuel back into the fuel chamber at the fuel inlet , the movement of the piston when the one-way valve is disabled serves only to extract the fuel from the fuel inlet to the fuel chamber and then eject the fuel out of the fuel chamber back to the fuel inlet.
31 An internal combustion engine according to claim 1, in which the / each fuel injector is mechanically driven by means of a cam surface, the fuel injector comprises a flexible diaphragm by means of a cam surface to eject the fuel. fuel injector, the surface of cams comprise a plurality of cam lobes that can cause a deflection of the diaphragm during a motor cycle and the controller that controls how many of those cam lobes in each motor cycle causes the piston to eject the fuel out of / each fuel injector.
32. An internal combustion engine according to claim 31, wherein the / each fuel injector comprises a body having a fuel chamber and a fuel outlet through which the fuel is expelled out of the chamber. for fuel when flexing the diagram, the / each fuel injector has a fuel inlet through which fuel is introduced into the fuel chamber, the / each fuel injector also has a one-way inlet valve that serves to allow fuel to flow into the fuel chamber from the fuel inlet while preventing the flow of fuel back from the fuel chamber to the fuel inlet and a one way outlet valve serving to allow fuel to flow out of the combustion chamber towards the fuel outlet preventing at the same time the flow back to the combustion chamber ible from the fuel outlet.
33. An internal combustion engine according to claim 31 or 32, comprising control means capable of rendering one or more of the lobes of the cam surface inoperable, the controller uses cam control means to control how many cam lobes Each motor cycle causes the diagram to flex and eject the fuel out of the fuel injector.
34. An internal combustion engine comprising: a variable volume combustion chamber; an air intake system to supply charge air to the combustion chamber; an exhaust system to expel burned gas from the combustion chamber into the atmosphere; and a fuel injection system for supplying the fuel in the cargo air to be burned with it in the combustion chamber; wherein the fuel injection system comprises: a fuel injector that functions as a positive displacement pump and supplies a quantity of fuel that is fixed for each and every operation of the injector; and a controller that controls the operation of each of the plurality of fuel injectors: wherein: in each of the at least a majority of engine cycles of the fuel injectors are operated on a plurality of occasions by the controller; in response to the increase in engine speed and / or engine load the amount of fuel increases for the engine cycle as the number of times the fuel injectors are operated by engine cycles increases; and in response to the reduction of the engine speed and / or the load of the controller the fuel supplied per engine cycle is reduced in quantity by reducing the number of occasions that the fuel injectors are operated by engine cycles; and the fuel injector is driven mechanically by means of a cam surface, the fuel injector has a piston driven by means of a thrust spring and displaceable by means of the cam surface, with the movement of the piston in one direction sucks fuel into a fuel chamber of the fuel injector and movement of the piston in the other direction expels fuel out of the fuel chamber, the cam surface comprises a plurality of cam lobes each of which can drive the piston during each engine cycle and the controller controls how many cam lobes in each engine cycle cause the piston to eject the fuel out of the fuel injector; the fuel injector has a fuel outlet through which the fuel is expelled out of the chamber by means of the piston and a fuel inlet through which the fuel is introduced into the fuel chamber, the fuel injector it also has a one-way inlet valve that serves to allow fuel to flow into the fuel chamber from the fuel inlet while preventing the flow of fuel back from the fuel chamber to the fuel inlet and a fuel valve. output of a path that serves to allow fuel to flow out of the combustion chamber towards the fuel outlet while preventing the flow back to the fuel chamber from the fuel outlet; and the one-way inlet valve can be disabled by the controller and when it is disabled allows the fuel flow back to the fuel chamber to the fuel inlet, the movement of the piston when the one-way valve is disabled serves only to Extract the fuel from the fuel inlet to the fuel chamber and then expel the fuel out of the fuel chamber back to the fuel inlet.
35. An internal combustion engine comprising; a variable volume combustion chamber; an air intake system to supply charge air to the combustion chamber; an exhaust system to expel burned gas from the combustion chamber into the atmosphere; and a fuel injection system for supplying the fuel in the cargo air to burn with it in the combustion chamber; wherein the fuel injection system comprises: a plurality of fuel injectors of which each operates as a positive displacement pump and supplies a quantity of fuel that is fixed for each and every operation of the injector, at least one first injector of fuel of the plurality of fuel injectors supplying a fixed amount of fuel different from a second fixed quantity supplied by a second fuel injector of the plurality of fuel injectors; a controller that controls the operation of each of the plurality of fuel injectors; wherein: in each one of the at least a majority of engine cycles of the fuel injectors are operated on a plurality of occasions by the controller; in response to the increase in engine speed and / or engine load the amount of fuel increases for the engine cycle as the number of times the fuel injectors are operated by engine cycles increases; in response to the reduction of the engine speed and / or the load of the controller the fuel supplied per engine cycle is reduced in quantity by reducing the number of occasions that the fuel injectors are operated by engine cycles; and each fuel injector is driven mechanically by means of a cam surface, the fuel injector has a piston driven by means of a thrust spring and displaceable by means of the cam surface, with the piston movement • in one direction fuel is extractable to a fuel chamber of the fuel injector and movement of the piston in the other direction expels fuel out of the fuel chamber, the cam surface comprises a plurality of cam lobes each of which can drive to the piston during each engine cycle and the controller controls how many cam lobes in each engine cycle cause the piston to eject the fuel out of the fuel injector.; each fuel injector has a fuel outlet through which the fuel is expelled out of the chamber by means of the piston and a fuel inlet through which the fuel is introduced into the fuel chamber, the fuel injector it also has a one-way inlet valve that serves to allow fuel to flow into the fuel chamber from the fuel inlet while preventing the flow of fuel back from the fuel chamber to the fuel inlet and a fuel valve. output of a path that serves to allow fuel to flow out of the combustion chamber towards the fuel outlet while preventing the flow back to the fuel chamber from the fuel outlet; and the one-way inlet valve can be disabled by the controller and when it is disabled allows the fuel flow back to the fuel chamber to the fuel inlet, the movement of the piston when the one-way valve is disabled serves only to Extract the fuel from the fuel inlet to the fuel chamber and then expel the fuel out of the fuel chamber back to the fuel inlet.
36. An internal combustion engine according to claim 34 or 35, in which a one-way inlet valve is provided with an electrically controlled control solenoid by means of the controller, the control solenoid serves to act upon a limiting needle that can be coupled with the first one-way valve to open the first one-way valve.
37. An internal combustion engine according to any one of claims 34 to 36 wherein all the cam lobes have an identical height.
38. An internal combustion engine according to any one of claims 34 to 37 wherein the cam lobes is provided on a wheel that also has a constant radius section- 39. An internal combustion engine according to any one of of claims 34 to 38 wherein the piston of each fuel injector has a follower cam which is a roller follower which engages with and follows the cam surface.40. An internal combustion engine according to any one of the preceding claims having an inlet passage through which air is supplied to a combustion chamber of the engine, a venturi provided in the inlet passage, a valve in the passage of inlet and a bypass passage that supplies air to the inlet passage current below the throttle valve, where the / each fuel injector supplies fuel to a mixed chamber in which the fuel is mixed with the air from the bypass passage with the mixed fuel and the air then it is supplied by means of a nozzle to a throat of the venturi. 43. An internal combustion engine according to any one of claims 40 to 42 wherein the nozzle is a sonic nozzle. 44. An internal combustion engine according to any one of claims 40 to 43 wherein the nozzle is an atomizing nozzle having a non-circular orifice. 45. An internal combustion engine according to any one of claims 40 to 43 wherein the nozzle is a spray nozzle having an array of holes. 46. A method for operating an internal combustion engine according to any one of claims 1 to 25 and 28 to 45, the method consists of: using the / each fuel injector to supply the combustion chamber in each cycle of motor a plurality of fuel pulses; and varying the number of fuel pulses between engine cycles in response to changes in engine speed and / or load to thereby control a total amount of fuel supplied to the combustion chamber in each cycle. 47. A method according to claim 46 in which the number of fuel pulses per engine cycle is maintained at a first level for a period immediately after the engine is started and reduced to lower levels for subsequent engine cycles. until the engine restarts.