WO2010132924A1

WO2010132924A1 - System, method and components for steam power

Info

Publication number: WO2010132924A1
Application number: PCT/AU2010/000578
Authority: WO
Inventors: Martin De Silva
Original assignee: Martin De Silva
Priority date: 2009-05-18
Filing date: 2010-05-18
Publication date: 2010-11-25

Abstract

An engine (12) may be configured to operate on a flash steam cycle. A water circuit (11) includes a pump (18) and heat source (16) for pressuring and heating water in the water circuit (11) to above a flash steam point. An injector (14) injects the heated water into a chamber of an engine (12). The heated water flashes to steam to drive the engine, e.g. by performing work on a piston or rotor. Exhaust steam may be recirculated through the engine for a secondary expansion stage before being condensed and returned to the pump (18). The heater (16) may include an inductive heater and may be integrated into the injector (14).

Description

SYSYTEM, METHOD AND COMPONENTS FOR STEAM POWER

FIELD OF THE INVENTION

This invention relates to heat generation devices and in particular to heat generation as a source of flash steam for engines. The invention further relates to engines and energy generation systems using steam principles.

BACKGROUND OF THE INVENTION

The problem facing the steam engine until now is that it wastes two to four times the heat energy that is wasted by the internal combustion engine. However, due to the fact that it relies on external combustion, the steam engine has the potential to recover waste heat from the exhaust steam and add it back as energy on the inlet side of the engine. This is something that the gasoline or diesel engine cannot do because of the substantial loss of volumetric efficiency which this would entail. The heat produced by the internal combustion engine is therefore irrecoverably wasted whilst that in the steam engine is substantially recoverable.

As the steam engine uses an external heat source, volumetric efficiency is not an issue. The only limit to heat recovery is the effectiveness of the heat exchange systems. In traditional steam engines such systems were bulky and added significant cost. They were altogether uneconomic and impractical in such applications as the steam locomotive. Whilst the Rankin cycle limits the extraction of heat energy in the working cycle of the steam engine, there is practically no limit to re-using waste heat in this type of system. What is required, is an improved energy conversion system that reduces heat losses. What is also required is an improved heat source for providing heat to the energy conversion system.

SUMMARY OF THE INVENTION

In one aspect of the disclosure, there is provided a system including an engine including at least one chamber; at least one injector for providing water to the at least one chamber; a water circuit including the at least one injector and the at least one chamber; at least one pump configured to pressurize water in the water circuit between the pump and an inlet side of the engine, an inlet of the pump being provided on an exhaust side of the engine such that exhaust from the engine is recirculated to the pump; and a primary heat source for heating water in the water circuit between the at least one pump and an inlet side of the engine. The at least one pump and the primary heat source cooperate to pressurize and heat the water such that the at least one injector delivers liquid water to the at least one chamber at a temperature and pressure that is above a flash steam point with respect to the environment of the at least one chamber .

In one aspect of the disclosure, there is provided a method for operating an engine including heating and pressurizing water in a water supply line to above a flash steam point; injecting the heated and pressurized water into a chamber of an engine; collecting exhaust steam expelled by the engine; and returning the exhaust steam to the water supply line.

In one aspect of the disclosure, there is provided a heat source for heating a water supply to a steam engine. The heat source includes an electrically conductive heater block; one or more water channels disposed within the heater block; and at least one inductive heating element disposed adjacent a first side of the heater block.

In one aspect of the disclosure, there is provided an injector for a water supply to a steam engine. The injector includes an electrically conductive injector body that defines a delivery chamber, the delivery chamber including an inlet configured to receive water; a nozzle including an outlet for the delivery chamber; an actuator for selectively opening the nozzle; and an inductor coil disposed around the injector body and configured to inductively heat the injector body.

In one aspect of the disclosure, there is provided a four- stage piston engine including one or more pistons, one or more of the pistons including: a piston chamber; at least one first injector; at least one second injector; a first exhaust port; and a second exhaust port. The second injector is connected to one of the first exhaust ports of the one or more pistons.

In one aspect of the disclosure, there is provided a rotary engine including one or more rotary chambers, the one or more rotary chambers including a first injector; a second injector; a first exhaust port; and a second exhaust port. The second injector receives exhaust from a first exhaust port of at least one of the rotary chambers.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference will now be made, by way of example only, to specific embodiments and to the accompanying drawings in which:

Figure 1 schematically shows an energy system including a water circuit having a high pressure side and a low pressure side;

Figure 2 shows a flowchart of a method for operating the energy system of Figure 1; Figure 3 schematically shows an internal view of a heat source;

Figure 4 schematically shows a cross section of a heater block;

Figure 5 schematically shows a coil and magnet arrangement;

Figure 6 schematically shows a radiant surface burner as a secondary heat source;

Figure 7 schematically shows a solar arrangement as a secondary heat source;

Figure 8 schematically shows an alternative inductive heating system;

Figure 9 schematically shows a modified Wankel engine;

Figure 10 schematically shows a modified Wankel engine housing;

Figure 11 schematically shows a modified 2-stage piston;

Figure 12 schematically shows a modified 4-stage piston;

Figure 13 schematically shows a modified 4-piston engine;

Figure 14 schematically shows a modified turbine arrangement;

Figure 15 schematically shows a heat exchanger;

Figure 16 schematically shows a modified injector; and

Figure 17 schematically shows an alternative radiant surface heat source.

DETAILED DESCRIPTION OF THE INVENTION

The foregoing description makes references to known engine types that in the prior art typically operate on internal combustion principles. In reference to these types of engines, the term combustion chamber may be used to identify the element of the engine to which this term commonly refers. However, it will be noted, that in the embodiments of the present invention, no combustion takes place in these chambers. In Figure 1, there is shown an energy conversion system in accordance with an embodiment of the invention. In the system 10, an engine 12 includes at least one chamber. By way of example, the engine 12 may be a piston engine of any suitable number of cylinders, a rotary engine having a suitable number of chambers, or a turbine. Other engine types will be apparent to a person skilled in the art.

Each chamber is provided with at least one injector 14. The injector 14 and engine 12 are two elements within a water circuit 11. A primary heat source 16 and a pump 18 cooperate to provide super heated water to the injector 14. No other fuel source is required to be input into the engine 12. Where the engine has multiple chambers and/or multiple injectors are deployed, a distribution manifold 15 may also be provided that distributes heated water to each of the injectors 14.

The system 10 works on a flash steam principle, illustrated in the flowchart 200 of Figure 2. Water in the water circuit is pumped by the pump 18 to the heat source 16 which heats the pressurized water to super heated temperatures (step 201). Table 1 shows an extract from standard steam tables and shows that the saturation temperature of water at 1450 PSI, for example, is 311 degrees C. That is, at a pressure of 1450 PSI, the water in the water line will remain in the liquid phase (i.e. does not turn to steam) up to a temperature of 311 degrees C. This principle allows liquid water to store larger quantities of heat energy provided sufficient pressure is maintained.

Table 1. Steam table showing flash point relationship between temperature and pressure The heated and pressurized water is provided to the injector 14 and released in timed doses by the injector 14 into the chamber 13 of the engine 12 (step 202) . The timing of the injector 14 may be controlled by an electronic control unit 17. The environment of the chamber, being at lower pressure than in the water line leading up to the injector, is below the flash steam point. Thus, the reduced pressure encountered by the super heated water in the chamber of the engine causes the water to "flash" to steam. The resulting volumetric expansion of the steam propels the engine, e.g. by driving a piston, rotor, turbine etc.

The flashing process results in "wet steam" being created because only part of the water is converted to steam whilst the rest is atomized by the flashing process into tiny droplets of water. The proportion of water converted to steam is obtained by subtracting the internal energy of the water at the lower pressure from that at the higher pressure.

The wet steam is exhausted from the chamber 14, collected (step 203) and recirculated (step 204) to the inlet side of the pump 18, thereby forming a complete water circuit 11. Other than for small losses within the engine, such as through the piston rings of a piston engine, the water circuit 11 is a substantially sealed system.

Depending on the length of the water circuit from the engine exhaust to the pump inlet, a condenser 19 can be placed on the exhaust side of the engine 12 to condense the wet steam exhaust to liquid water before it reaches the pump 18. As will be described in detail below, the condenser 19 may be provided by way of a heat exchanger that transfers heat from the water lines of the engine exhaust side to the water lines on the pressurized side of the pump 18 prior to the primary heat source 16. In this way, the system employs minimal heat losses. The system 10 has advantages over conventional steam driven engines in which steam is provided to the chamber. Employing an injector to deliver liquid water rather than admitting steam through an inlet valve is of considerable practical advantage. Firstly the volume of water injected at each stroke is far smaller than the volume of steam passing the inlet valve in an engine served by a modern mono-tube generator (steam at atmospheric pressure occupies about 1650 times the volume of water) .

This small quantity of water is much easier to dispense through an injector than the much larger volume of steam which an inlet valve must admit in a conventional modern mono-tube engine. Such a small quantity of water may be dispensed at speeds equal to those found in diesel injection systems, whereas steam which has to negotiate an inlet valve is seriously impeded if the engine is pushed to higher speeds by a phenomenon known to steam engineers as "wire-drawing".

The system 10 requires at least one heat source 16. In various embodiments, a primary heat source may be supplemented by one or more secondary heat sources. The heat source is preferably one that is efficient and environmentally sound. In one embodiment, the heat source may include at least one induction heater. An internal view of an embodiment of an induction heating system 30 is illustrated schematically in Figure 3.

The heating system 30 includes a substantially rectangular heater block 40 shown in cross-sectional side view in Figure 4. The heater block 40 includes a water inlet 41 that accesses one or more internal water channels of the heater block. Heated water exits the heater block 40 from an outlet 42. Mounted on the heater block 40 is a substantially planar thermal insulator 32 which thermally isolates a conductive coil 34 from the heater block 40. In one embodiment, the ceramic insulator is a flat sheet of ceramic of approximately 2mm in thickness. Spacers, e.g. also of ceramic, may be used to provide an air gap between the coil 34 and the ceramic insulator to further thermally isolate the coil 34 from the heater block 40. In one embodiment, the ceramic insulator 32 may be removed and an air gap used to thermally isolate the coil 34 from the heater block 40. A plurality of magnets 36 may optionally be provided on the coil 36. The coil 34 and magnets 36 may be contained in a casing 38 that may be mounted onto ceramic insulate 32 and/or the heater block 40.

The heater system 30 works on an inductive heating principle. An alternating current is provided to the coil 34 which produces an alternating magnetic field that emanates from the coil 34 and penetrates the metal of the heater block 40. Eddy currents are established within the heater block that cause resistive heating of the heater block 40. Heat generated in the heater block is transferred to the water within the channels of the heater block 40. Where the material of the heater block 40 is of relatively substantial magnetic permeability, magnetic hysteresis losses also enhance the heating of the heater block 40.

The heater block 40, shown in more detail in Figure 4, includes a water inlet 41 and an outlet 42. In one embodiment, the heater block may be a single piece of metal into which an inlet channel 44 and an outlet channel 45 are drilled from the inlet 41 and outlet 42 respectively. A series of cross channels 46 may be drilled and plugged from the side face to connect between the inlet channel 44 and outlet channel 45, thereby defining a number of water paths within the heater block. The inlet 41 and outlet 42 may each be internally threaded for connection of the inlet and outlet water lines respectively. In one specific embodiment, the heater block 40 is approximately 200mm X 200mm X 70mm. The inlet and outlet channels extend approximately 170mm into the heater block and are approximately 140mm apart. The water volume of the heater block is approximately 21OmL. In practice, the size and internal volume of the heater block will be most dependent on the power output requirements of the engine 12 and thus the volume, temperature and pressure of water required to be supplied by the heat source 30.

Figures 3 and 4 show just one example of a heater block 40 and a person skilled in the art would recognize that other arrangements of the channels would be possible. For example a single channel could be provided by a serpentine path within the heater block rather than having an inlet channel, an outlet channel and multiple cross channels. While the inlet and outlet are shown as being on the same side of the heater block, the inlet and outlet could be arranged on different sides.

The terms top, bottom, side etc used herein are made with reference to particular orientations shown in the Figures. However, a person skilled in the art will readily understand that alternative orientations may be made and all such orientations are considered to be equivalent unless otherwise indicated or suggested.

The coil arrangement is shown in greater detail m Figure 5. In one embodiment, the coil is a flat spiral coil 47 of insulated copper wire providing a substantially planar coil arrangement that may sit parallel to the ceramic insulator 32. A series of radial magnets 36 may be provided on the coil 47, e.g. by gluing or other fixing means. In one embodiment, the casing 38 may be used to locate the magnets 36 on the coil 34. The magnets operate to direct the fields produced by the coil 34 toward the heater block 40, thereby enhancing the inductive heating within the heater block 40 for a given set of coil operating parameters. The magnets 36 may also act to limit the field effects external to the casing 38. In one embodiment, the magnets are rare earth magnets that provide a high magnetic field strength at a relatively high Curie point.

The coil includes connectors 37, 39 that extend from the casing 38 for connecting the coil to a power source (not shown) , such as mains supply, or an inverter and battery arrangement. Ceramic or other insulators may be provided in the casing 38 for electrically isolating the coil 34 and the connectors 37, 39 from the casing 38.

The use of the inductive heating system as the primary heat source is advantageous because it provides an efficient heating system and also has rapid response times for tuning the power output of the engine. In addition, the heater block 40 has a relatively large thermal mass. Since most of the heat is returned to the system, once the heater block 40 is at operating temperature, the heater block 40 can provide high pressure hot water to the injectors with only minimal energy input. In a working prototype, the heater block 40 was able to continue to deliver heated water to the engine 12 operating at idle, for 4 hours after power to the heater block was disconnected. The only power being input to the system was at the pump 18 to pressurize the water.

An advantage of the heater block arrangement of Figures 3 to 5 is that the side surface 49 of the heater block 40 that is opposite the coil 34 provides a relatively large surface area that can be thermally coupled to one or more secondary heat sources. If no secondary heat source is required, the heater block may be insulated to limit heat losses. The surface 49 may be provided with one or more mountings 43 such as holes, latches, projections, etc., that receive attachments for a secondary heat source.

In one embodiment, a secondary heat source may be provided by a radiant surface burner, such as a ceramic burner. An example of a radiant surface burner 50 is illustrated in Figure 6. An optimal ratio gas/air mixture is provided from a gas supply 53 to a chamber 52 via a gas inlet 51. The chamber 52 has an array of exit pores 54 (three examples are indicated in Figure 6) . Overlying the exit pores 54 is a porous emitter surface 56, e.g. comprised of a refractory ceramic. The principle of operation of the radiant surface burner is that the premixed air and gas pass through the burner body 52 and out through the porous emitter surface 56. The gas combusts along only the thin outer surface of the emitter surface 56, thereby heating the emitter to create high radiating temperatures of approximately 600 to 1100⁰C. The emitter surface then emits infrared energy 58 in the micron range most efficient for heating. By placing the emitter surface 56 in close proximity to the heater block 49, the emitter surface 56 is thermally coupled to the heater block 49 and thereby can be used to provide a secondary heat source to the heater block 40.

Radiant burners are premix type burners in which air and gas are mixed and delivered to the burner for firing under pressure. Various gasses can be used including natural gas, compressed natural gas (CNG) , liquid petroleum gas (LPG) , methane and virtually any gaseous fuel. Because the system 50 burns its gas externally the precise control of the fuel burned is maintained so as to optimize fuel consumption and ensure emissions are minimal.

In one embodiment, the gas source 53 may be a source of premixed gas. In one embodiment, the gas source may be a pure gas source that passes through a mixer 59, for example a venturi valve, that entrains a required quantity of air into the gas mixture. In one embodiment, the equipment for mixing may include an air blower and a venturi mixer. Air is delivered under pressure to a mixer having a metering orifice. This orifice determines the volume of air at any pressure delivered to the burner. The pressure of air is controlled by a butterfly valve ahead of the mixer. After leaving the orifice, the air is expanded through the venturi of the mixer to create suction on the gas line.

Gas is delivered to the mixer 59 from the gas supply 53 through an air/gas ratio regulator. This regulator reduces the pressure of the gas to atmospheric or zero pressure. Therefore, when the air is expanded through the venturi m the mixer, the resultant suction on the gas line mixes a proportionate flow of gas to the flow of air - which is then delivered to the burner. In one embodiment, the Stoichiometric ratio of 10 parts air to 1 part gas is provided to achieve maximum fuel efficiency.

After the gas mixing system 59 (or premixed source gas) , a single valve throttling control 57 may be provided that controls the amount of gas/air mixture delivered to the burner in an accurate ratio through its entire adjustment range. The control system 57 may receive control signals from the electronic control unit 17 to adjust the flow of gas to the burner system 50, thereby controlling the heat output of the burner system 50 that is thermally coupled into the heater block 40.

The use of a radiant surface burner 50 is beneficial, in particular for the secondary heat source, because they have high efficiency but are also finely controllable and so can be readily adjusted for the required power output of the engine 12.

Though the burner system 50 has been described in the examples as a secondary heat source, a person skilled in the art will recognize that the radiant burner 50 may also be used as a primary heat source in various embodiments.

In one embodiment, a secondary heat source may be a solar heat source. In a simple form, a solar water heater may be provided as a component between the pump 18 and the primary heat source 16. In an alternative embodiment, solar reflectors, e.g. one or more mirrors may direct sunlight onto the surface 49 of the heater block 40. In a further alternative embodiment, illustrated in Figure 7 a Fresnel lens 62 may be provided to capture sunlight 67 and concentrate the sunlight onto the secondary heater surface 49 of the heater block 40, thereby thermally coupling the lens 62 onto the heater block 40. Since the Fresnel lens 62 can capture light from a wide angle, the Fresnel lens may be of a similar size to the surface 49 of the heater block 40 and may be mounted directly on the surface 49 of the heater block 40. The heater block 40 may therefore be provided with mountings, such as the mountings 43 (Figure 3) to receive the Fresnel lens assembly.

Alternatively, as shown in the example of Figure 7, a larger Fresnel lens 62 may be provided on a frame 64. The frame 63 spaces the Fresnel lens 62 from the heater block 40 and holds the Fresnel lens 62 substantially parallel to the surface 49 of the heater block. Fresnel lens have advantages for this embodiment in that they can be relatively inexpensive and can softly focus sunlight from a relatively wide area and from a wide range of incident angles onto the heater block 40, thereby removing the need for more complex, expensive and energy intensive tracking systems. However, in various embodiments, the heater block 40 may be provided on a platform or support 65 that is attached to a multi-directional pivot mounting 69 that allows the heater block 40 and/or the Fresnel lens 62 to be adjusted for the sun angle. A sensor and tracking system 64 may be equipped with a motor drive and used for automatically adjusting the angle of the pivot mount.

While the Fresnel lens has been described, other mirror and lens arrangements may be used for concentrating solar radiation onto the heater block.

In addition to a solar concentrator that provides radiant energy onto the heater block 40, one or more photovoltaic elements 66 may also be provided that convert solar energy to electrical energy. The electrical energy may be provided directly to an inverter as a source of power for the inductor of the primary heat source. Alternatively, the electrical energy may be provided to one or more batteries 61 for storage and use in the electronic control unit 17, firing the injectors 14, powering the tracking systems 64, etc.

Control circuitry may be provided to maximize solar energy use while available, thereby reducing the power consumption requirements of the primary heat source from other sources such as batteries, gas supplies, etc.

The control circuitry may also control an arrangement that reduces solar energy collection when not required, to prevent the heater block 40 from overheating. The solar control arrangement may include a shutter 68 that blocks the Fresnel lens 62 or intercepts the sunlight between the Fresnel lens 62 and the heater block 40. The solar control arrangement may alternatively control the alignment between the Fresnel lens 62 and the heater block to adjust the amount of sunlight that impinges on the heater block 40.

While the control aspects have been described with specific reference to the Fresnel lens arrangement of Figure 7, a person skilled in the art would readily understand that these arrangements could similarly apply to other solar collector arrangements, such as a solar water heater, a mirror arrangement, etc.

While specific examples of a radiant surface burner and a solar collector have been offered for the secondary heat source, other forms of secondary heat source will be apparent to a person skilled in the art. Furthermore, in various embodiments, any of these secondary heat sources could be used as alternative primary heat sources.

The heater block 40 must be capable of withstanding water at the required operating temperature and pressure. Resistance to oxidation, or scaling are also important factors and thus stainless steel is a suitable material for the heater block. As described above, it is preferable, though not essential, to use a material that has a substantial magnetic permeability m order to enhance the magnetic hysteresis heating of the heater block 40. To satisfy these requirements, in one embodiment, the 400 series of stainless steels are used for the heater block 40. In specific examples, the heater block may be made from 431 grade or 440 grade stainless steels.

An alternative construction of the primary heat source is illustrated in Figure 8. In this embodiment, a unit 80 is comprised of a conductive metal rail 81 disposed inside a cylindrical coil 82. The rail 81 is tubular and provides a portion of the water circuit of the system 10 for water 84 flowing through the rail. The heat source of Figure 8 works on the same inductive heating principle described above with respect to Figures 3 to 5. That is, an alternating current provided to the heater coil 82 creates an alternating magnetic field that penetrates the rail 81, thereby inductively heating the rail 81. Heat generated in the metal rail is transferred to the water 84 passing through the rail 81. As for the earlier embodiments, the heating may be enhanced by choosing an electrical conductor that also has a relatively high magnetic permeability, such as the types of stainless steel described above .

The coil 82 and rail 81 may be provided within a housing, such as the cylindrical housing 85. Fittings 86 may be provided on the housing 85 for connection of the water line and provision for the electrical connections to the coil 82 may also be integrated. The unit 80 may therefore be produced as a modular unit that can be readily integrated into the system 10. One or more magnets may also be placed within the housing to intensify the magnetic field within the water rail 81.

The heat source 80 shown in Figure 8 can be made relatively compact with a short heating line. The heat source 80 can therefore provide a convenient pre-heating source provided as a secondary heat source either prior to or after the pump 18 in the system 10. Modular units of the heat source 80 may also be produced in various lengths and sizes to be integrated into various engine systems.

The pump 18 used for pressurizing the water circuit prior to the injectors may be any pump suitable for the purpose. In one embodiment, the pump 18 may be a common rail diesel pump. One such pump is the Bosch CPl pump which has a pressurizing range between 250 Bar and 1350 Bar (approx 3600 PSI to 19500 PSI) . A person skilled in art will readily understand that the specific pump to be used will depend not only on the pressure required in the water circuit, but also on the flow of water required at the engine to meet the required power outputs. For example, a single piston engine could use a smaller pump than a multi-piston engine. The pump may derive its power from an external battery supply, a mains supply or from a power coupling from the engine 12. The water circuit may further include a filter (not shown) . The filter may be placed in the water circuit 11 directly. Alternatively, a water supply (not shown) may be provided to top up the water m the water circuit when required. The water supply may be connected to the water circuit via a filter. Level and/or pressure sensors may provide feedback to the electronic control unit 17 to control when water is provided from the water supply into the water circuit of the system 10.

The injector (s) 14 may be any suitable injector. In one embodiment, solenoid operated injectors are used. It is preferable, though not essential, that the injectors have a relatively fast open and close time, of the order of 2ms. In one embodiment, the internal surfaces of the injector may be ceramic coated to provide higher resistance to scaling.

As described above, the principle of operation of the system 10 is to use expanding steam in the engine chamber (s) to drive the engine to perform work. The super heated water which flashes to steam can therefore provide a substitute for the combustible fuel of many known engine types. Accordingly, many of these known engine types may be modified to operate using the water circuit 11 of the system 10 m place of a fuel supply. In addition, these known engine types may further be modified so that the heat and energy of the exhaust gases, which contain only wet steam, can be returned to the system instead of being exhausted to the environment.

In one embodiment, the system 10 may utilize a Wankel type rotary engine. An advantage of this type of engine is that it is of a relatively simple construction with minimal moving parts. An embodiment of the Wankel engine is shown in Figure 9. The Wankel engine 90 includes a housing 91 that houses a rotor 92 mounted on an eccentric shaft 93. Ordinarily intake and exhaust would be provided on one side of the chamber while ignition would be provided on the other. In a single rotation, the rotor 92 would ordinarily pass through four stages, namely intake, compression, ignition and exhaust, to produce a 4 cycle engine.

In the modified Wankel engine illustrated, the housing 91 is modified, as shown in Figure 10. The housing 10 is provided with an additional injector aperture so that two injector apertures 101, 102 can each receive an injector. A first injector 94 is disposed in aperture 102 and a second injector 95 is disposed in aperture 101. Similarly, an additional exhaust port may be provided so that the housing 91 includes a first exhaust port 103 on a first side of the housing 91 and a second exhaust port on the second side of the housing 91. External to the housing, a holding chamber 96 connects to the exhaust port and receives exhaust gases. The holding chamber outlets to the injector 95, which may be a check valve injector. The second exhaust port 94 provides exhaust to the condenser 19.

The first injector 94 receives heated water from the heat source 16 and provides it into a first chamber 97 defined between the rotor 92 and the housing 91. The primary expansion of the steam in chamber 97 provides the primary power stroke for the rotor 92. Exhaust gas in the exhaust chamber 98 is expelled through the first exhaust port 103 and into the holding chamber 96. At the conclusion of the primary power stroke, the wet steam still retains some useful energy. In prior art engine systems, this energy would normally be exhausted immediately to the condenser and this energy would be lost. In the modified system of Figures 9 and 10, the holding chamber 96 retains the wet steam until the check valve injector 95 opens. The wet steam is then drawn into the secondary expansion chamber 99 where it provides a secondary power stroke, though of reduced power compared to the primary power stroke in primary chamber 97. The secondary expansion chamber 99 exhausts through the exhaust port 104 to the condenser. The return and re-use of the "warm" steam increases the efficiency of the engine 12 by allowing as much energy to be extracted from the steam prior to the condenser 19. This not only increases the efficiency of the engine in isolation, but also increases the efficiency of the water circulation system because less energy needs to be extracted from the steam in the condenser 19.

The example provided in Figures 9 and 10 shows a single rotary Wankel engine. Where a multiple rotary engine is provided, the primary exhaust of one rotary chamber may be redirected to the secondary expansion of a second primary chamber. For example, where back to back rotary chambers are used in a dual rotary system, the primary exhaust port 103 of the front rotary chamber may connect to the secondary injector 95 of the rear rotary chamber. This has advantage because the primary exhaust will almost immediately be required m the secondary expansion chamber and so minimal holding of the wet steam will be required. That is, a primary chamber of one rotor can exhaust directly into the secondary chamber of the other rotor.

Figures 9 and 10 refer to a modified Wankel engine that produces a 4-cycle engine with two power strokes. It will be apparent to a person skilled in the art that the flash steam principles could equally be applied to an un-modified Wankel engine that does not recirculate exhaust steam from the primary expansion. The unmodified Wankel engine would thus have the standard four-stage cycle of an intake, compression, power and exhaust stages. However, the intake ports could be disabled so that there was no opening of the ports during intake, or so that only standard air was cycled through the system.

In a further embodiment, the check valve injector 95 could be replaced with another one of the injectors 94 that receives water directly from the heat source 16. The Wankel engine would then become a 2-stage cycle engine which had two complete power strokes through one rotation. In this embodiment, each of the exhaust ports 103, 104 would exhaust the wet-steam directly to the condenser 19.

In one embodiment, the engine 12 may utilize a piston engine. The piston engine may be a two-cycle engine 110 as illustrated in Figure 11. A typical piston engine 110 includes an engine block 111 that defines a combustion chamber 112 in which a piston 113 is disposed. The 2-cycle piston engine includes a power stroke (downstroke) and an exhaust stroke (upstroke) through which exhaust gases are expelled through exhaust port 116. The construction and operation of a 2-cycle piston engine is well known and further detailed operation of the piston is not considered essential here.

For use as a steam engine, the 2-cycle piston engine 110 is provided with a steam injector 114 that receives pressurized heated water from the heater source 16 (not shown in Figure 11) .

Table 2 provides a comparison between the internal combustion engine (ICE) and the 2-Cycle flash steam engine presently described.

Table 2. Timing comparisons between 2-cycle ICE and flash steam

As Table 2 shows, for a 2-cycle engine, the injector 114 injects the heated water at top dead centre and the exhaust port opens at bottom dead centre after the power stroke. In a further embodiment, the engine 12 of the system 10 may also be based on a 4-cycle engine. For a 4-cycle ICE, the standard cycles are an intake stroke, compression stroke, power stroke and an exhaust stroke. A side schematic view of a modified 4-cycle piston engine 120 is shown in Figure 12. As for the 2-cycle piston engine of Figure 11, the 4-cycle piston engine 120 includes an engine block 121, combustion chamber 122 and piston 123. Also shown are primary and secondary injectors 124, 134 that respectively provide pressurized heated water 125 and recirculated water 135 to the chamber 122, as will be described in greater detail below. An intake valve 126 would, in an ordinary ICE, provide access to an air intake 128 and an exhaust valve 127 would exhaust gases through exhaust port 129.

In one embodiment, the 4-cycle piston engine could be modified to operate as a 2-cycle engine by disabling the intake valve 126 and causing the exhaust valve 127 to open on every upstroke. The injector could be made to fire at the start of every downstroke so that each downstroke becomes a full power stroke .

In an alternative embodiment, the 4-cycle engine could be modified so that wet-steam exhausted after the primary power stroke can be recirculated into the piston chambers to provide a secondary power (expansion) stroke, thereby extracting as much energy from the steam as possible. Figure 13 shows a 4 piston engine that uses recirculated exhaust. The pistons may be numbered left to right as 1, 2, 3, 4. Each piston, e.g. piston 4 133 is connected via an exhaust port 129 to the exhaust manifold which first circulates 131 through the engine block 121 and then 132 to the condenser (not shown) . Each piston also includes two injectors 124 and 134. A primary injector 124 receives pressurized hot water 125 via a distribution manifold (not shown) from the heat source 16. The secondary injector 134 connects to the air intakes of the pistons in an arrangement depending on the firing order of the cylinders. The cams on the camshaft (not shown) that control the air intake valves 126 may be rotated 180 degrees so that instead of opening at the start of the intake stroke, they open on the exhaust stroke. Similarly, the cams for the exhaust valve 127 may be adjusted so that the exhaust valve opens on what would normally have been the compression stroke for an ICE engine. Thus, the ordinary ICE stroke cycle of Intake, Compression, Power, Exhaust, is modified to Power (Primary expansion) , Internal Primary Exhaust, Secondary Expansion, External Secondary Exhaust.

For a piston firing order of 1, 3, 4, 2, the internal exhaust/secondary injector connections may be as shown in Figure 13. For example, the primary exhaust 137 through the intake valve 136 of piston 2 is redirected to the secondary injector 134 of piston 4. Likewise, the primary exhaust 138 from piston 4 is provided to the secondary expansion stroke of piston 2. Pistons 1 and 3 are similarly connected.

Table 3 shows a comparison between the combustion cycles of a 4-stroke ICE piston engine and the 4-cycle flash steam engine presently described.

Open Open

Where only a single 4-cycle piston is deployed, the wet steam can be circulated from the air intake valve 127 to the secondary injector 134 of that piston via a holding chamber similar to the holding chamber 96 shown in Figure 9 for the Wankel engine embodiment.

A turbine engine is illustrated in Figures 14. In these embodiments, heated water is injected from an injector 143 to immediately behind the vanes 141 of a turbine 142 within a housing 145. The expanding steam 144 spins the turbine 142. Wet steam may be extracted from an exhaust vent (not shown) and returned to the water circuit.

It has heretofore been shown that a large variety of engine types can be used and/or modified for use as the engine 12 in the system 10 of Figure 1. These modifications may be made to two and four stroke, petrol and diesels, and single and multi- cylinder (multi-chamber) engines and turbine engines. Other engine types may also be apparent to a person skilled in the art and the system presently described is considered to broadly encompass all suitable engine types.

As shown in Figure 1, the system 10 may be controlled by an electronic control unit 17. The unit 17 provides timing and control signals to the injectors 14. In one embodiment, the timing signals may be provided to the injectors via a common- rail diesel system. The control unit 17 may receive feedback from various sensors in the system 10. Example sensors may include, but are not limited to, water pressure sensor, engine speed sensor, throttle control or throttle position indicator, steam exhaust temperature sensor, condenser pressure sensor, water level sensor, etc. Control code used by the control unit 17 may follow current methodologies and logic, so as to be easily diagnosed for maintenance and repair purposes.

Though not shown for clarity, the system 10 may include various safety devices such as pressure relief valves and the like that prevent an over-pressure situation from occurring.

In one embodiment, the condenser 19, if used, may incorporate a heat exchanger 150 depicted schematically in Figure 15. In general, the lowest temperature point on the system is immediately after the pump. The heater exchanger may therefore include an exhaust gas line 151 having an inlet 152 that receives the exhaust gases from the engine 12 and outlets condensed water from an outlet 153 towards the pump. The heat exchanger 150 may also include a water supply line 154 having an inlet 155 from the pump 18 and an outlet 156 toward the heat source 16. The exhaust line 151 and water supply line 154 may be configured within the heat exchanger so that heat flows from the exhaust line 151, being the hotter line, to the water supply line 154, as indicated by arrow 157. It is considered to be within the purview of a person skilled in the art to locate the heat exchanger 150 elsewhere within the water circuit in a manner that minimizes heat and energy losses from the system.

In a further alternative embodiment of the primary heat source, an inductive heater element may be integrated into the injectors used to inject the superheated water into the engine chambers. An internal view of a modified injector is illustrated in Figure 16. A typical injector includes a body 161 that defines an internal delivery chamber 162 that delivers the fluid source via an outlet 163 of a nozzle 164. A needle 165 selectively closes the nozzle 164. A solenoid 166 or similar actuator actuates the needle 165 by drawing the needle 165 further into the delivery chamber 162, i.e. away from the outlet of the nozzle and thereby opening the nozzle. In the modified injector, an insulated inductive coil 167 may be wrapped around the body 161 of the injector 160. One or more magnets 168 may optionally be disposed around the coil 167 to force the inductive field produced by the coil 167 to be concentrated into the core of the injector. A casing 169, e.g. of an alloy, may enclose the magnets 168 and coil 167 of the injector.

The delivery chamber 162 is connected to a pressurized water supply 170, e.g. provided by the pump 12, via a distribution manifold if required.

When an appropriate current is applied to the coil 167, the body of the injector 161 within the coil 167 is inductively heated, including, if conductive, the body of the needle 165. Heat is therefore transferred to the water within the delivery chamber 162. An advantage of this embodiment, is that the amount of water that is heated may be limited to approximately 4mL. The timing of the inductive heating may be offset from the actuation of the solenoid 166 to ensure that the magnetic fields of each do not interfere.

In a further adaptation, a small pump can be provided at the back end of the injector. The pump may be, for example, a piezo-electπcally operated pump that pressurizes the water in the delivery chamber. By providing heating and/or pressurizing at the injector, the amount of the water circuit that needs to be heated and pressurized is reduced, which can lead to energy efficiency gains . A further advantage is that because only a small volume is pressurized, failure of a single device will not be as catastrophic as if a larger volume were under pressure.

Timing signals may control when electrical current is provided to the heater coil 167 of the integrated injector 160 so that the water is only heated when necessary. In one embodiment, the timing signals may further be used for tuning a multi-cylinder engine to meet power output requirements by reducing the number of operating cylinders.

A secondary heat source may be provided for the integrated injector by an inline cylindrical radiant surface burner as shown in Figure 17. This burner works on the same principles as the radiant burners described above. However, in this case, the radiant surface is provided by a cylindrical ceramic 172 disposed within a cylindrical body 173. The water rail 174 with inlet water 175 and outlet 176 is provided at the center of the housing 173 with an air gap 179 between the ceramic burner 172 and the water rail 174. Gas is inlet 177 to the ceramic burner 172 and burns at the inner surface of the ceramic 172. The heated ceramic 172 then radiates onto the metal rail 174 which transfers the heat to the water 175. Burnt gas exhaust is expelled from the air gap 179 via an outlet 178.

The secondary heat source of Figure 17 may be provided immediately adjacent the integrated injector of Figure 16. In one embodiment, modular connectors may be provided for allowing easy connection between the integrated injector and the cylindrical burner heat source.

In an alternative or additional embodiment, the inline inductive heater shown in Figure 8 may also be used as a preheat source prior to the integrated injector.

Applications of the steam driven embodiments herein described include small scale power production, e.g. based on the integrated injector, to very large scale power generation systems. Remote and rural systems may be made to be self contained with sufficient batteries and solar secondary sources. The steam engines may also be suitable for use in automotive applications including general consumer cars and vehicles, bus fleets, etc. Although embodiments of the present invention have been illustrated in the accompanied drawings and described in the foregoing description, it will be understood that the invention is not limited to the embodiments disclosed, but is capable of numerous rearrangements, modifications, and substitutions without departing from the spirit of the invention as set forth and defined by the following claims. For example, the capabilities of the invention can be performed fully and/or partially by one or more of the blocks, modules, processors or memories. Also, these capabilities may be performed in the current manner or in a distributed manner and on, or via, any device able to provide and/or receive information. Further, although depicted m a particular manner, various modules or blocks may be repositioned without departing from the scope of the current invention. Still further, although depicted m a particular manner, a greater or lesser number of modules and connections can be utilized with the present invention in order to accomplish the present invention, to provide additional known features to the present invention, and/or to make the present invention more efficient. Also, the information sent between various modules can be sent between the modules via at least one of a data network, the Internet, an Internet Protocol network, a wireless source, and a wired source and via a plurality of protocols .

Claims

WHAT IS CLAIMED IS:

1. A system including: an engine including at least one chamber; at least one injector for providing water to the at least one chamber; a water circuit including the at least one injector and the at least one chamber; at least one pump configured to pressurize water in the water circuit between the pump and an inlet side of the engine, an inlet of the pump being provided on an exhaust side of the engine such that exhaust from the engine is recirculated to the pump; and a primary heat source for heating water in the water circuit between the at least one pump and an inlet side of the engine; wherein the at least one pump and the primary heat source cooperate to pressurize and heat the water such that the at least one injector delivers liguid water to the at least one chamber at a temperature and pressure that is above a flash steam point with respect to the environment of the at least one chamber.

2. The system according to claim 1 including a condenser in the water circulation circuit for condensing steam exhaust from the at least one chamber into a liquid phase prior to the pump .

3. The system according to 1 including a heat exchanger including : a first water line including a first inlet that receives water from an outlet side of the at least one pump and passes the water to a first outlet that leads to an inlet side of the primary heat source; and a second water line including a second inlet that passes exhaust from the engine to a second outlet that leads to the inlet of the at least one pump; wherein the first water line and second water line are disposed such that heat can be transferred from the second water line to the first water line.

4. The system according to claim 1 including a secondary heat source configured to heat water in the water circuit between the pump and the inlet side of the engine.

5. The system according to claim 4 wherein the primary heat source includes a heater block and wherein the secondary heat source is thermally coupled to at least one external surface of the heater block.

6. The system according to claim 5 wherein the secondary heat source includes at least one radiant surface burner adjacent the at least one external surface of the heater block.

7. The system according to claim 5 wherein the secondary heat source includes at least one solar element.

8. The system according to claim 7 wherein the solar element includes at least one Fresnel lens that concentrates sunlight onto the at least one external surface of the heater block.

9. The system according to claim 1 wherein the primary heat source includes: at least one electrically conductive water channel element; and at least one inductor coil configured to inductively heat the at least one water channel element.

10. The system according to claim 9 wherein the at least one injector includes a conductive body that includes the water channel element and wherein the at least one inductor coil is disposed around the body of the injector.

11. The system according to claim 1 wherein the engine includes a recirculation system that receives exhaust steam after a primary expansion and directs the exhaust steam into the engine for a secondary expansion.

12. The system according to claim 11 wherein the engine receives exhaust steam from a first chamber of the engine and directs the exhaust steam into a second chamber of the engine .

13. The system according to claim 11 wherein the engine includes a rotary engine including one or more rotary chambers, the one or more rotary chambers including: a first injector; a second injector; a first exhaust port; and a second exhaust port; wherein the second injector receives exhaust from a first exhaust port of at least one of the rotary chambers.

14. The system according to claim 11 wherein the engine includes a piston engine including one or more pistons, one or more of the pistons including: a piston chamber; at least one first injector; at least one second injector; a first exhaust port; and a second exhaust port; wherein the first injector receives pressurized heated water from the primary heat source; and wherein the second injector receives wet steam from one of the first exhaust ports of the one or more pistons.

15. The system according to claim 1 wherein the engine includes a modified 4-cycle internal combustion engine and wherein the engine is modified to replace an intake stage, compression stage, power stage and exhaust stage of a combustion cycle with a primary expansion stage, internal exhaust stage, secondary expansion stage and external exhaust stage of a flash steam cycle.

16. A method for operating an engine including: heating and pressurizing water in a water supply line to above a flash steam point; injecting the heated and pressurized water into a chamber of an engine; collecting exhaust steam expelled by the engine; and returning the exhaust steam to the water supply line.

17. The method according to claim 16 including heating the water in the water supply line using a primary inductive heating source and at least one secondary heat source.

18. The method according to claim 16 including: performing a primary expansion of the steam in the engine; collecting exhaust steam after the primary expansion; returning the exhaust steam to the engine; and performing a secondary expansion of the returned exhaust steam.

19. A heat source for heating a water supply to a steam engine, the heat source including: an electrically conductive heater block; one or more water channels disposed within the heater block; and at least one inductive heating element disposed adjacent a first side of the heater block.

20. The heat source according to claim 19 wherein the at least one inductive heating element is disposed within a housing and wherein the housing is mounted to the first side of the heater block.

21. The heat source according to claim 19 including at least one thermal insulator disposed between the inductive heating element and the heater block.

22. The heat source according to claim 19 including a secondary heat source thermally coupled to at least one second side of the heater block.

23. The heat source according to claim 22 wherein the secondary heat source includes at least one of a radiant surface burner and a solar element.

24. An injector for a water supply to a steam engine, the injector including: an electrically conductive injector body that defines a delivery chamber, the delivery chamber including an inlet configured to receive water; a nozzle including an outlet for the delivery chamber; an actuator for selectively opening the nozzle; and an inductor coil disposed around the injector body and configured to inductively heat the injector body.

25. The injector according to claim 24 including one or more magnets disposed on the inductor coil.

26. The injector according to claim 25 including a piezoelectric pump configured to pressurize water in the delivery chamber.

27. A four-cycle piston engine including one or more pistons, one or more of the pistons including: a piston chamber; at least one first injector; at least one second injector; a first exhaust port; and a second exhaust port; wherein the second injector is connected to one of the first exhaust ports of the one or more pistons.

28. The four-cycle piston engine according to claim 27 wherein the engine is an internal combustion engine and wherein the first exhaust port includes an intake port of the internal combustion engine.

29. The four-cycle piston engine according to claim 28 wherein the engine includes a modified 4-stage internal combustion engine and wherein the engine is modified to replace an intake stroke, compression stroke, power stroke and exhaust stroke of a combustion cycle with a primary expansion stroke, internal exhaust stroke, secondary expansion stroke and external exhaust stroke of a flash steam cycle.

30. A rotary engine including one or more rotary chambers, the one or more rotary chambers including: a first injector; a second injector; a first exhaust port; and a second exhaust port; wherein the second injector receives exhaust from a first exhaust port of at least one of the rotary chambers.

31. The rotary engine according to claim 30 wherein the engine operates on a four stage flash steam cycle including a primary expansion stage, an internal exhaust stage, a secondary expansion stage and an external exhaust stage.