WO2009044412A2 - Système d'injection d'air-carburant pour moteurs à combustion interne à deux temps - Google Patents

Système d'injection d'air-carburant pour moteurs à combustion interne à deux temps Download PDF

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Publication number
WO2009044412A2
WO2009044412A2 PCT/IN2008/000640 IN2008000640W WO2009044412A2 WO 2009044412 A2 WO2009044412 A2 WO 2009044412A2 IN 2008000640 W IN2008000640 W IN 2008000640W WO 2009044412 A2 WO2009044412 A2 WO 2009044412A2
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WIPO (PCT)
Prior art keywords
engine
air
compressor
valve
fuel
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Application number
PCT/IN2008/000640
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English (en)
Other versions
WO2009044412A3 (fr
Inventor
Ramesh Asvathanarayanan
Loganathan Marimuthu
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Indian Institute Of Technology
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Publication of WO2009044412A2 publication Critical patent/WO2009044412A2/fr
Publication of WO2009044412A3 publication Critical patent/WO2009044412A3/fr

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B33/00—Engines characterised by provision of pumps for charging or scavenging
    • F02B33/02—Engines with reciprocating-piston pumps; Engines with crankcase pumps
    • F02B33/06—Engines with reciprocating-piston pumps; Engines with crankcase pumps with reciprocating-piston pumps other than simple crankcase pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B33/00—Engines characterised by provision of pumps for charging or scavenging
    • F02B33/02—Engines with reciprocating-piston pumps; Engines with crankcase pumps
    • F02B33/28—Component parts, details or accessories of crankcase pumps, not provided for in, or of interest apart from, subgroups F02B33/02 - F02B33/26
    • F02B33/30—Control of inlet or outlet ports
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B39/00—Component parts, details, or accessories relating to, driven charging or scavenging pumps, not provided for in groups F02B33/00 - F02B37/00
    • F02B39/02—Drives of pumps; Varying pump drive gear ratio
    • F02B39/04—Mechanical drives; Variable-gear-ratio drives
    • F02B39/06—Mechanical drives; Variable-gear-ratio drives the engine torque being divided by a differential gear for driving a pump and the engine output shaft
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M67/00—Apparatus in which fuel-injection is effected by means of high-pressure gas, the gas carrying the fuel into working cylinders of the engine, e.g. air-injection type
    • F02M67/10—Injectors peculiar thereto, e.g. valve less type
    • F02M67/12—Injectors peculiar thereto, e.g. valve less type having valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M69/00—Low-pressure fuel-injection apparatus ; Apparatus with both continuous and intermittent injection; Apparatus injecting different types of fuel
    • F02M69/04—Injectors peculiar thereto
    • F02M69/042—Positioning of injectors with respect to engine, e.g. in the air intake conduit
    • F02M69/045—Positioning of injectors with respect to engine, e.g. in the air intake conduit for injecting into the combustion chamber

Definitions

  • This document relates generally to a two-stroke internal combustion engine, and more particularly, but not by way of limitation, to a method and apparatus for an air-fuel mixture injection system that can be configured to be adapted to an application.
  • Two-stroke engines are simple in construction, cheap to produce and maintain, and have a high power to weight ratio. They also have lower friction losses than four-stroke engines with similar power outputs. Two-stroke engines can be preferred over four-stroke engines in vehicular applications such as mopeds, small scooters, snowmobiles, or hand-held power tools. Further, in developing countries like India, a large number of two-stroke engines are used in three- wheeled vehicles in urban areas for transportation. Two-stroke engines in these applications have high fuel consumption and high levels of hydro-carbon (HC) and carbon monoxide (CO) emissions.
  • HC hydro-carbon
  • CO carbon monoxide
  • Two-stroke engines have a problem of short-circuiting when fuel is injected into the cylinder, such as during the scavenging phase.
  • short-circuiting the fresh fuel that is injected into the cylinder via an input port does not stay in the cylinder long enough to be burned, but instead rather quickly exits the output port of the cylinder along with the exhaust.
  • Short-circuiting decreases fuel efficiency. For example, because of short circuiting, fuel efficiency of a two- stroke internal combustion engine can decrease by 25% to 40%, and the emission of un-bumt HCs increases.
  • Use of electronically controlled manifold fuel injection systems, which are popular in four-stroke engines, have not significantly improved fuel economy or reduced HC emission in two-stroke engines.
  • the present inventors have recognized, among other things, the limited potential of certain approaches that attempt to reduce fuel short circuiting by injecting fuel through the cylinder barrel or the transfer port.
  • the present inventors have also noted that, in order to completely avoid short-circuiting, an approach can be to inject fuel into the cylinder after the exhaust ports close.
  • the present inventors have also recognized that certain approaches to avoiding short-circuiting can include high pressure injection, air-assisted injection using electrp/iic controls, or using pump-less systems.
  • an embodiment of the present system and method can provide an air-fuel mixture to a two-stroke internal combustion engine.
  • the system can include an air compressor.
  • the air compressor can include a compressor inlet valve, a compressor outlet valve, and a compressor piston.
  • a two-stroke internal combustion engine can be connected to the compressor.
  • the engine can include an engine cylinder, an engine cylinder head, and an engine air-fuel inlet valve at the engine cylinder head.
  • a pipe can communicate air and fuel between the outlet valve of the compressor and the engine air-fuel inlet valve.
  • An air-fuel mixture can be provided to the engine cylinder through an engine air-fuel inlet valve, timed by the outlet valve of the compressor.
  • the engine air-fuel inlet valve can be actuated by a pressure difference between the pipe and the engine cylinder.
  • the outlet valve of the compressor is configured to be in a specified phased relationship to the compressor piston.
  • the compressor piston is configured to be in a specified phased relationship with the engine.
  • a system can comprise an air compressor, comprising a compressor inlet valve, a compressor outlet valve, and a compressor piston.
  • a two-stroke internal combustion engine can be connected to the compressor.
  • the engine can include an engine cylinder, an engine cylinder head, and an engine air-fuel inlet valve at the engine cylinder head.
  • a pipe can communicate air and fuel between the outlet valve of the compressor and the engine air-fuel inlet valve.
  • An air-fuel mixture is provided to the engine cylinder through the engine air-fuel inlet valve, timed by the outlet valve of the compressor.
  • the engine air-fuel inlet valve is actuated by a pressure difference between the pipe and the engine cylinder.
  • the outlet valve of the compressor is configured to be in a specified phased relationship to the compressor piston.
  • the compressor piston is configured to be in a specified phased relationship with the engine.
  • Example 2 the system of Example 1 can optionally be configured such that the air-fuel mixture is provided to the engine cylinder such that less short circuiting of fuel in the engine cylinder occurs during a scavenging cycle as compared to a like engine having the air,fuel mixture provided via a manifold.
  • Example 3 the system of any one or more of Examples 1-2 can optionally be configured such that the compressor comprises a pin on the compressor piston, wherein the pin configured to actuate the compressor outlet valve.
  • Example 4 the system of any one or more of Examples 1-3 can optionally be configured such that the pin on the compressor piston is configured to open the compressor outlet valve when the compressor piston is near top dead center (TDC).
  • TDC top dead center
  • Example 5 the system of any one or more of Examples 1-4 can optionally be configured such that the ⁇ in ⁇ n the compressor piston is configured to open the compressor outlet valve when the compressor piston is in a range that is between about 15 degrees before top dead center (TDC) to about 60 degrees before TDC of the engine.
  • TDC top dead center
  • Example 6 the system of any one or more of Examples 1-5 can optionally be configured such that the compressor can provide pressurized air at a pressure that is within a range between about 2 bars and about 7 bars to atomize the fuel.
  • Example 7 the system of any one or more of Examples 1-6 can optionally be configured such that wherein the compressor output valve is configured to open at a specified crank angle of the compressor, wherein the crank angle is in a range that is between top dead center (TDC) and about 60 degrees before TDC of the compressor.
  • TDC top dead center
  • Example 8 the system of any one or more of Examples 1-7 can optionally be configured such that a swept volume of a cylinder of the air compressor is in a range that is between about 2% and about 20 % of a swept volume of the engine cylinder.
  • Example 9 the system of any one or more of Examples 1-S can optionally be configured such that the air compressor is connected to the engine in a specified phased relationship by at least one of a pulley system, a gear, or a cam.
  • Example 10 the system of any one or more of Examples 1-9 can optionally be configured such that the engine air-fuel inlet valve comprises- a poppet valve.
  • Example 11 the system of any one or more of Examples 1-10 can optionally be configured such that the poppet valve is configured to inject the air- fuel mixture in a direction that is substantially opposite to a direction of scavenging gases moving through the engine cylinder, and in a direction such that that a combustible mixture is formed in a spark zone provided by a spark plug on the engine cylinder head.
  • Example 12 the system of any one or more of Examples 1-11 can optionally be configured such that the compressor inlet valve comprises a reed valve configured to receive, for introduction into a cylinder of the compressor, air and a liquid lubricant.
  • the compressor inlet valve comprises a reed valve configured to receive, for introduction into a cylinder of the compressor, air and a liquid lubricant.
  • Example 13 the system of any one or more of Examples 1-12 can optionally comprise at least one of a carburetor, or a low pressure injector, operable in a range of about 2 bar to about 5 bar, having an output configured to supply fuel to the pipe.
  • a carburetor or a low pressure injector, operable in a range of about 2 bar to about 5 bar, having an output configured to supply fuel to the pipe.
  • Example 14 includes a timing air-fuel inlet valve assembly for a two-stroke internal combustion engine.
  • the timing air-fuel inlet valve assembly can include an auxiliary cylinder to an engine.
  • the cylinder can include a piston, an input port, and a output port.
  • the piston can include a piston pin, located at an end face portion of the piston and configured to actuate the output port.
  • a valve body can be at or near the output port.
  • a movable valve can be configured to move within a tapered collar from a resting position at which the movable valve can provide a substantially airtight seal with the collar.
  • the movable valve can comprise a distal end in mutual cooperation with the pin of the piston end to actuate the movable valve.
  • the piston pin can be configured to trigger the distal end of the movable valve to open the output port of the cylinder when, in a piston cycle, the piston nears top dead center (TDC).
  • TDC top dead center
  • Example 15 the valve assembly of Example 14 can optionally be configured such that the movable valve comprises at least one. of a pin valve, a spring-loaded valve, or a solenoid valve.
  • Example 16 the valve assembly of any one or more of Examples 14-15 optionally can be configured to open the output port of the cylinder at a plurality of crank angles and speeds of the engine.
  • Example 17 the valve assembly of any one or more of Examples 14-16 can optionally be configured such that the piston pin is configured to trigger the movable valve to open when the piston of the auxiliary cylinder , in a range between about 0 degrees and about 60 degrees before TDC of the auxiliary cylinder, and to close when the piston of the auxiliary cylinder is in a range that is between about 0 degrees and about 60 degrees after TDC of the auxiliary cylinder.
  • Example 18 describes a method.
  • the method can i comprise cyclically compressing air in a phased relationship with a two-stroke engine, initiating release of the compressed air into a pipe at a specified phase of at least one of the engine and a compressor, and mixing fuel into the compressed air in the pipe.
  • An inlet valve can be actuated, using Ia pressure difference between the compressed air and an engine cylinder pressure, for opening the valve and injecting an air-fuel mixture into the cylinder.
  • Example 19 the method of Example 18 can optionally comprise directing the injected air-fuel mixture in a direction generally toward a spark zone and generally opposing a direction of scavenging air flow during a scavenging cycle of the two-cycle engine while an exhaust port of the engine is still open.
  • Example 20 the method of any one or more of Examples 18-19 can optionally be performed such that injecting the air-fuel mixture into the cylinder comprises reducing a short circuiting as compared to providing the air-fuel mixture via a manifold or transfer duct from a crank case of the engine.
  • FIG. 1 illustrates a functional block diagram of an example of the present air-fuel injection system.
  • FIG. 2 illustrates an example of portions of a process using the present air-fuel inject-on system shown in FIG. 1.
  • FIG. 3 illustrates a cross-section of an example of the present pin valve mounted on a cylinder head of a compressor.
  • FIG. 4'A illustrates a cross section of an example of the present poppet valve injector.
  • FIG. 4B illustrates a diagram ofip ' ositr ⁇ ing of the present poppet vaive on a cylinder head of a cylinder of a two-stroke engine, such as with respect to a spark plug and scavenging air flow.
  • FIG. 5 is a photograph that illustrates an example of formation of a cloud air-fuel mixture using an example of portions of the present system such as shown and described with respect to FIG. 1.
  • FIG. 6A is a chart depicting an example of injection timing of the air-fuel mixture demonstrating optimum output power as achieved using an example of the present system such as shown and described with respect to FIG. 1.
  • FIG. 6B is a chart depicting an example of injection timing of the air-fuel mixture demonstrating optimum efficiency as achieved using an example of the present system such as shown and described with respect to FIG. 1.
  • FIG. 7A is a chart depicting an example of hydrocarbon (HC) emission using injection timing with a timing valve opening time at 25% throttle as achieved using an example of the present system such as shown and described with respect to FIG. 1.
  • HC hydrocarbon
  • FIG. 7B is a chart depicting an example of the carbon monoxide (CO) emission using injection timing with a timing valve opening time at 25% throttle as achieved using an example of the present system such as shown and described with respect to FIG. 1
  • CO carbon monoxide
  • FIG. 8A is a chart comparing (1) an example of the output power provided by a two-stroke commercially available engine using manifold injection of gasoline compared to (2) an example of the output power provided by the same engine.tegnfigtired using the present air-fuel mixture injection scheme such as illustrated in the example of FlG. 1.
  • FIG. 8B is a chart comparing (1) an example of the hydrocarbon (HC) emission provided by a two-stroke commercially available engine using manifold injection of gasoline compared to (2) an example of the HC emission provided by the same engine configured using the present air-fuel mixture injection scheme such as illustrated in the example of FIG. 1.
  • HC hydrocarbon
  • FIG. 9A is a chart comparing (1) an example of the carbon monoxide (CO) emission vs. power output provided by . a two-stroke commercially available engine using manifold injection of gasoline compared to (2) an example of the CO emission vs. power output provided by the same engine configured using the present air-fuel mixture injection scheme such as illustrated in the example of FIG. 1.
  • CO carbon monoxide
  • FIG. 9B is a chart comparing (1) an example of the equivalence ratio vs. power output provided by a two-stroke commercially available engine using manifold injection of gasoline compared to (2) an example of the equivalence ratio vs. power output provided by the same engine configured using the present air-fuel mixture injection scheme such as illustrated in the example of FIG. 1.
  • FiG. 10 is a chart comparing (1) an example of the nitric oxide (NO) emission vs. power output provided by a two-stroke commercially available engine using manifold injection of gasoline compared to (2) an example of the NO emission vs. power output provided by the same engine configured using the present air-fuel mixture injection scheme such as illustrated in the example of FIG. 1.
  • NO nitric oxide
  • DESCRiPTlOM nitric oxide
  • FIG. 1 illustrates a functional block diagram of an example of the present air-fuel injection system 5.
  • the air-fuel injection system 5 can include a compressor 10 (e.g., a 25 cc air-compressor, or the like), a two-stroke internal combustion (IC) engine 30 (e.g., a 150 cc IC engine, or the like), a pulley drive 31 , a compressor inlet valve 17 (e.g., a reed valve, other one-way valve, or the like), a compressor outlet valve 18 (e.g., a piston-pin driven movable valve, other one-way valve, or the like), a fuel introducer 22 (e.g., a carburetor or low pressure fuel injector), a high pressure line 20 (als ⁇ o referred to as a "high pressure pipe", e.g., a pipe, tube, or other conduit), and an engine air-fuel inlet valve 24 (e.g., a poppet valve, or other one-way
  • a 150 ce two-stroke IC engine 30 can be used, such as described for illustrative purposes in Table 1.
  • the IC engine need not be air-cooled, and other implementations can also vary from the illustrative example described in Table 1.
  • FiG. 1 shows an example in which the compressor 10 can be connected to a two-stroke internal combustion engine 30 by a toothed pulley and belt drive 31 (e.g., a 1:1 drive).
  • the drive 31 maintains a proper specified phasing between the compressor 10 and the IC engine 30 (e.g., a 1 :1 phase relationship between compressor cycles and engine cycles).
  • the compressor 10 can be mounted on the IC engine 30.
  • the specified phasing between the compressor 10 and the IC engine 30 can be controlled by a chain, by a cam, or by any other suitable technique of maintaining the phase relationship.
  • the compressor 10 comprises a co ⁇ ipressor cylinder body 12, and a distal compressor cylinder head 13.
  • a compressor piston can be located within the cylinder body 12.
  • the cylinder head 12 can include a compressor input port 14 and a compressor output port 16.
  • the input port 14 can include or be connected to a compressor inlet valve 16.
  • the compressor inlet valve 16 admits a mixture of air and a lubricator into the cylinder body 12 via the input port 14 in the cylinder head 12.
  • the valve 17 can include a reed valve.
  • Other types of openings or valves can be used, such as to admit the mixture of air and lubricant.
  • a set of holes distributed about the circumference of the cylinder head 12 can be used to admit the mixture of air and lubricant.
  • valve 17 can be adjustably timed to open at a specified engine or compressor crank angle, which timing may be controllably varied at different operating speeds of the engine 30 or the compressor 10.
  • the compressor output port 16 can include or be connected to a compressor outlet valve, such as a pin valve 18, which can include a valve that is actuated by a pin on an end face of the compressor piston that is located within the cylinder body 12. Connected to the pin valve 18 is a high pressure pipe 20. in the example of FIG.
  • the high pressure pipe 20 is connected to a fuel source 22, such as a low pressure injector or a carburetor, which introduces fuel into the high pressure pipe 20.
  • the high pressure pipe 20 can connect the low pressure injector or other fuel source 22 to a poppet valve injector or other engine air-fuel inlet valve 24 that is attached to the cylinder head 26 at a distal end of the cylinder body 27 of the two-stroke internal combustion engine 30.
  • the engine air-fuel inlet valve 24 includes a poppet valve injector that can be positioned on the cylinder head 26 of the engine 30 near a spark plug.
  • a distance between the spark plug and the poppet valve can be about 50 mm.
  • the poppet valve injector can be placed such as shown in FIG. 4B, e.g., on the same side of the cylinder body 27 as an exhaust port. In another example, the poppet valve injector can be placed on an opposite side of the cylinder body 27 from the exhaust port.
  • the poppet valve injector can be spring-loaded such that, in operation, the poppet valve injector can open and close in response to a pressure differential between the cylinder and the high pressure pipe 20.
  • the spring of the poppet valve injector can be configured to inhibit or prevent unwanted leakage from the cylinder, such as from pressure differentials across the poppet valve injector other than the actuating pressure differential created by the compressor 10 to actuate the poppet valve injector.
  • the poppet valve injector can inject the air-fuel mixture from the high pressure pipe 20 into an engine cylinder in cooperation with the compressor outlet valve, such as to inhibit, reduce, or minimize short-circuiting of the injecting air-fuel mixture out the exhaust port during the scavenging cycle of the two-cycle engine.
  • the poppet valve injector can be oriented with respect to the engine cylinder head 26 such that an air-fuel mixture is injected in a direction opposite to a scavenging gas flow and toward a spark zone, so as to improve the atomization or combustion of the air-fuel mixture within the cylinder.
  • FIG. 2 describes an example of portions the present process 50 that includes injecting an air-fuel mixture into the two-stroke internal combustion engine 30 of FIG. 1.
  • the process 50 begins.
  • air and optionally, a lubricant
  • the amount of lubricant mixed with the air is, in an example, enough to lubricate the compressor 10.
  • the amount of lubricant can range from about 1-2% of the fuel to be injected. In another example, the amount of lubricant can be about 0.5% of the amount of fuel to be injected.
  • the compressor piston 72 (shown in FIG. 3) cycles until the compressor piston 72 reaches near top dead center (TDC).
  • the exhaust port 16 (shown in FIG. 3) on compressor 10 is appropriately timed to open and exhaust compressed air .
  • timing can be obtained using a pin valve 18 that opens the exhaust port 16 when the compressor piston 72 nears TDC.
  • the phasing between the engine 30 and the compressor 10 can be such that the outlet valve on the compressor opens at between about 15 degrees and about
  • the compressed air can be ejected into the high pressure line 20.
  • the compressed air in the high pressure line 20 can be pressurized to a pressure that is between about 2 bar and about 5 bar.
  • fuel e.g., gasoline or the like
  • fuel introducer 22 can be injected by the fuel introducer 22 into the high pressure line 20.
  • This can include, for example, using a carburetor, a low pressure gasoline injector, or the like.
  • the high pressure air e.g., at above 2 bar presssure, such as at about 2-5 bar pressure
  • the fuel can be injected just before the pressurized air reaches the fuel introducer 22.
  • the fuel can be injected (e.g., by a fuel pump or an engine control unit) into the airflow of the pressurized air in the high pressure line 20.
  • the fuel can be pressurized at a pressure that is in a range between about 2 bar to about 20 bar, when injected to mix with the pressurized air in the high pressure line 20.
  • the pressurized air atomizes the fuel, such as to create a rich air-fuel mixture.
  • the duct shape fuel introducer 22, the pressure value of the compressed air, and the fuel metering rate into the high pressure line can affect the degree of atomization that occurs.
  • the pressure of the rich air-fuel mixture in the high pressure line 20 opens the engine air-fuel inlet valve 24, which can be a poppet valve injector.
  • the rich air-fuel mixture can be injected, via a cylinder head, into a cylinder of a two-stroke IC engine 30.
  • the rich air-fuel mixture atomizes into fine droplets, such as because of the compressed air injection and because of an opposing directional gaseous flow within the cylinder during its scavenging cycle. This helps form a combustible mixture inside the cylinder, such as in a spark zone where it can be ignited.
  • the process 50 can be repeated as shown by flow line 66 shown in the example of FIG. 2.
  • the process 50 allows the timing of the opening of the pin valve 18 to be made as late as possible, such that fuel short-circuiting is reduced or eliminated. This allows enough time for mixture preparation in the cylinder.
  • By reducing the fuel short-circuiting more fuel is available for > combustion. This can significantly reduce fuel consumption (e.g., by about 10- 20%). This can also significantly reduce hydrocarbon (HC) emission (e.g., by about 50%).
  • HC hydrocarbon
  • FIG. 3 illustrates a cross-section of an example of the present pin valve 18 mounted on the cylinder head 16 of a compressor 10 such as shown in FIG. 1.
  • the compressor 10 also includes an input valve such as a reed valve 310, such as to admit air (and optionally a lubricant) into the cylinder body 12 of the compressor 10.
  • the pin valve 18 can be configured as a timing Valve that can determine when compressed air is allowed to exit the compressor 10.
  • the timing valve can include a valve body 300.
  • a spring 302 mutually cooperates with a movable valve 304, which can include a tapered or conically moving part.
  • a collar 306 can be configured to accept the movable valve 304.
  • the spring 302 can be floating (e.g., untethered).
  • the collar 306 and the spring 302 can be configured to maintain the position of the movable valve as being seated against the collar 306 until actuated.
  • the timing valve can be attached to the output port 16 of the compressor cylinder body 12.
  • the compressor cylinder body 12 can house a piston 72 having a pin 308, such as can be located on an end face of the piston 72. Near top dead center (TDC), the pin 308 engages or otherwise mutually cooperates with the movable valve to actuate its opening by compressing the spring 302. This ejects compressed air through the output port 16 of the cylinder body 12 of the compressor 10.
  • the pin valve 18 provides a convenient and effective timing valve. However, in various examples, the pin valve 18 can be substituted or augmented by one or more of a spring-loaded valve, a solenoid valve, or other type of timing valve or the like that can be connected to the outlet port of the compressor.
  • FIG. 4A illustrates a cross-section of an example of the present poppet valve assembly that can be used as an engine air-fuel inlet valve 24 mounted on the cylinder head 26 of the engine 30 shown in FIG. 1.
  • the poppet valve assembly can include a movable poppet valve 400, a valve body 402A-B, a spring 404, and a spring retainer 406.
  • the poppet valve 400 can be configured within the valve body 402 to create a substantially air-tight and leak-proof seal, by holding the poppet valve 400 seated . against a collar 408 until actuated by the compressor 10, and then re-seating the poppet valve 400 after such actuation.
  • the spring retainer 406 is in mutual cooperation with the high pressure line 20 and in contact with the spring 404.
  • the spring 404 in turn, can be connected to the movable poppet valve 400.
  • the spring retainer 406 can hold the poppet valve 400 closed against the collar 408 until a specified pressure is reached in the high pressure line 20 (e.g., a pressure that is between about 2 bars and about 5 bars).
  • a specified pressure e.g., a pressure that is between about 2 bars and about 5 bars.
  • the spring retainer 406 pushes down on the spring 404. This, in turn, causes the poppet valve 400 to move away from the collar 408 of the valve body 402.
  • the angle of the interface between the head of the poppet valve 400 and the collar 408 of the valve body can be configured to help improve the distribution of the rich air-fuel mixture into the cylinder. This can enhance mixing of the atomized air-fuel mixture in the cylinder body 27 of the engine 30.
  • the poppet valve assembly shown in FIG. 4A can inhibit or prevent back-flow of the air-fuel mixture from within the cylinder body 27 back toward or into the high pressure line 20.
  • the poppet valve assembly can optionally include water or other liquid ports 41 OA-B, such as for liquid-cooling the poppet valve assembly. This can help promote longevity of one or more of the components of the poppet valve assembly, such as the spring 404.
  • the poppet valve assembly can serve as an engine air-fuel inlet valve 24 to inject the air-fuel mixture into the cylinder body 27 of the engine 30.
  • the poppet valve assembly shown in FIG. 4A can be positioned near the spark plug such that a combustible mixture is present near the spark plug at the time of ignition, and a suitable mixture that can burn with low emissions is present elsewhere, in an example, the orientation of the fuel injector can be such as shown in the example of FIG. 4B.
  • the exact location of the poppet valve can change, such as depending on the size of the engine cylinder.
  • the poppet valve can be located such that the spray direction is generally opposite the exhaust port.
  • FIG. 5 shows a photographic view of the air-fuel spray cloud from the poppet valve.
  • FIG. 6A is a chart depicting an example of injection timing of the air-fuel mixture demonstrating optimum output power as achieved using an example of the present system such as shown and described with respect to FIG. 1.
  • the timing valve opening time was taken at 25% throttle.
  • the best power output was obtained with a timing valve opening time that was about 60 degrees before Bottom Dead Center (bBDC) of the engine piston for a variety of air-fuel ratios as shown.
  • BBDC Bottom Dead Center
  • FIG. 6B is a chart depicting an example of injection timing of the air-fuel mixture demonstrating optimum efficiency as achieved using an example of the present system such as shown and described with respect to FIG. 1.
  • the timing valve opening time was taken at 25% throttle.
  • the best efficiency was obtained with a timing valve opening time that was about 30 degrees before Bottom Dead Center (bBDC) of the engine piston for a variety of air-fuel ratios as shown.
  • BBDC Bottom Dead Center
  • FIG. 7A is a chart depicting an example of hydrocarbon (HC) emission using injection timing with a timing valve opening time at 25% throttle as achieved using an example of the present system such as shown and described with respect to FIG. 1.
  • the timing valve opening time was taken at 25% throttle.
  • the lowest HC emission was observed with a timing valve opening time that was about 30 degrees before Bottom Dead Center (bBDC) of the engine at an air-fuel ratio of about 20, as shown.
  • BBDC Bottom Dead Center
  • FIG. 7B is a chart depicting an example of the carbon monoxide (CO) emission using injection timing with a timing valve opening time at 25% throttle as achieved using an example of the present system such as shown and described with respect to FIG. 1.
  • the timing valve opening time was taken at 25% throttle.
  • the lowest CO emission was observed with a timing valve opening time that was about 60 degrees before ⁇ Bottom Dead Center (bBDC) of the engine for a variety of air-fuel ratios as shown.
  • BBDC Bottom Dead Center
  • FIG. 8A is a chart comparing an example of (1) the brake thermal efficiency provided by an example of a two-stroke commercially available engine using conventional manifold injection of gasoline to (2) an example of the brake thermal efficiency of the same engine configured in accordance with the present air-fuel mixture injection system, such as shown and described with respect to FIG. 1. In both examples, brake thermal efficiency was measured at an engine speed of 3000 rpm.
  • FIG. 8A demonstrates that the present air-fuel injection system is better than the typical manifold injection at all outputs. Without being bound by theory, this is believed to result because of the reduction in the amount of fuel short-circuited.
  • FIG. 8A is a chart comparing an example of (1) the brake thermal efficiency provided by an example of a two-stroke commercially available engine using conventional manifold injection of gasoline to (2) an example of the brake thermal efficiency of the same engine configured in accordance with the present air-fuel mixture injection system, such as shown and described with respect to FIG. 1. In both examples, brake thermal efficiency was measured at an engine speed of 3000 rpm.
  • FIG. 8B is a chart comparing an example of (1) hydrocarbon emission provided by an example of a two-stroke commercially available engine using conventional manifold injection of gasoline to (2) an example of the hydrocarbon emission provided by an example of same engine configured using the present air-fuel mixture injection system, such as shown and described with respect to FIG. 1 .
  • FIG. 8B demonstrates that the conventional manifold system can produce hydrocarbon emission as low as about 1360 ppm.
  • the present air-fuel mixture injection system can further reduce hydrocarbon emission to a level of about 460 ppm.
  • the drop in hydrocarbon emission can be significant. Without being bound by theory, it is believed that this is because short circuiting of the fresh air-fuel mixture (e.g., fresh charge) is reduced or minimized.
  • reductions in hydrocarbon emission can be achieved, such as by reconfiguring the poppet valve injector to produce a finer atomization, reshaping the combustion chamber to produce a more conducive air movement pattern, optimizing the location of the poppet valve and the air pressure, optimizing the size and shape of the poppet valve, optimizing the location at which fuel is fed into the high pressure line 20, or the like.
  • FIG. 9A is a chart comparing (1) an example of the carbon monoxide (CO) emission vs. power output provided by a two-stroke commercially available engine using manifold injection of gasoline compared to (2) an example of the CO emission vs. power output provided by the same engine configured using the present air-fuel mixture injection scheme such as illustrated in the example of FIG. 1.
  • the present air-fuel mixture injection scheme exhibited more CO emission for a given power output. Without being bound by theory, it is believed that this is because there is not enough time for mixing in the present air-fuel mixture injection scheme as compared to a manifold injection arrangement in which pre-mixing occurs inside of a carburetor.
  • FIG. 9B is a chart comparing (1) an example of the equivalence ratio vs. power output provided by a two-stroke commercially available engine using manifold injection of gasoline compared to (2) an example of the equivalence ratio vs. power output provided by the same engine configured using the present air-fuel mixture injection scheme such as illustrated in the example of FIG. 1.
  • the present air-fuel mixture injection scheme exhibited a lower equivalence ratio for a given power output, meaning that most of the fuel sent into the engine is retained, rather than short-circuited. Without being bound by theory, it is believed that this indicates that the present air-fuel mixture injection scheme reduces or inhibits fuel short-circuiting as compared to a manifold injection arrangement.
  • FIG. 10 is a chart comparing (1) an example of the nitric oxide (NO) emission vs. power output provided by a two-stroke commercially available engine using manifold injection of gasoline compared to (2) an example of the NO emission vs. power output provided by the same engine configured using the present air-fuel mixture injection scheme such as illustrated in the example of FIG. 1.
  • the present air-fuel mixture injection scheme exhibited higher NO emission for a given power output. Without being bound by theory, it is believed that this is because the present air-fuel mixture injection scheme runs leaner, and therefore, traps more air, and produces more NO (comparable to a four-stroke engine) as compared to a manifold injection arrangement.
  • the NO emission can be controlled (to a reasonable extent), such as by adjusting spark timing, but such reduction in NO emission may also somewhat reduce fuel efficiency. ,

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fuel-Injection Apparatus (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)

Abstract

L'invention porte sur un système et un procédé qui permettent d'alimenter un moteur à combustion interne à deux temps en mélange air-carburant. Le système de l'invention peut comprendre un compresseur d'air. Le compresseur d'air peut comprendre une soupape d'entrée de compresseur, une soupape de sortie de compresseur et un piston de compresseur. Un moteur à combustion interne à deux temps peut être relié au compresseur. Le moteur peut comprendre un cylindre moteur, une tête de cylindre moteur et une soupape d'admission d'air-carburant de moteur sur la tête de cylindre moteur. Une conduite peut faire circuler l'air et le carburant entre la soupape de sortie du compresseur et la soupape d'admission d'air-carburant du moteur. Un mélange air-carburant peut être distribué au cylindre moteur via la soupape d'admission d'air-carburant du moteur, synchronisé par la soupape de sortie du compresseur. La soupape d'admission d'air-carburant du moteur peut être commandée par une différence de pression entre la conduite et le cylindre moteur. La soupape de sortie du compresseur est configurée pour se trouver dans une relation de phase spécifiée par rapport au piston du compresseur. Le piston du compresseur est configuré pour se trouver dans une relation de phase spécifiée par rapport au moteur.
PCT/IN2008/000640 2007-10-05 2008-10-06 Système d'injection d'air-carburant pour moteurs à combustion interne à deux temps WO2009044412A2 (fr)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2490106A (en) * 2011-04-13 2012-10-24 Ge Prec Engineering Ltd Forced induction for internal combustion engines
CN110848066A (zh) * 2019-09-30 2020-02-28 广西擎芯动力科技有限公司 一种点燃式二冲程重油活塞发动机

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0044738A1 (fr) * 1980-07-18 1982-01-27 Exxon Research And Engineering Company Récupération d'énergie d'effluent d'un réacteur sous pression
US5809949A (en) * 1994-09-09 1998-09-22 Institut Francais Du Petrole Two-stroke engine with improved injection device and associated injection process
DE19939898A1 (de) * 1998-08-25 2000-03-02 Walbro Corp Kraftstoff-Luft-Zuführeinrichtung für eine Brennkraftmaschine

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0044738A1 (fr) * 1980-07-18 1982-01-27 Exxon Research And Engineering Company Récupération d'énergie d'effluent d'un réacteur sous pression
US5809949A (en) * 1994-09-09 1998-09-22 Institut Francais Du Petrole Two-stroke engine with improved injection device and associated injection process
DE19939898A1 (de) * 1998-08-25 2000-03-02 Walbro Corp Kraftstoff-Luft-Zuführeinrichtung für eine Brennkraftmaschine

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2490106A (en) * 2011-04-13 2012-10-24 Ge Prec Engineering Ltd Forced induction for internal combustion engines
CN110848066A (zh) * 2019-09-30 2020-02-28 广西擎芯动力科技有限公司 一种点燃式二冲程重油活塞发动机

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