CN108571392B - Lean burn system and method for spark-ignition engine - Google Patents
Lean burn system and method for spark-ignition engine Download PDFInfo
- Publication number
- CN108571392B CN108571392B CN201710144104.3A CN201710144104A CN108571392B CN 108571392 B CN108571392 B CN 108571392B CN 201710144104 A CN201710144104 A CN 201710144104A CN 108571392 B CN108571392 B CN 108571392B
- Authority
- CN
- China
- Prior art keywords
- fuel
- cylinder
- engine
- air inlet
- lean
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/30—Controlling fuel injection
- F02D41/3011—Controlling fuel injection according to or using specific or several modes of combustion
- F02D41/3017—Controlling fuel injection according to or using specific or several modes of combustion characterised by the mode(s) being used
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/30—Controlling fuel injection
- F02D41/3094—Controlling fuel injection the fuel injection being effected by at least two different injectors, e.g. one in the intake manifold and one in the cylinder
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D43/00—Conjoint electrical control of two or more functions, e.g. ignition, fuel-air mixture, recirculation, supercharging or exhaust-gas treatment
-
- 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
- F02M31/00—Apparatus for thermally treating combustion-air, fuel, or fuel-air mixture
- F02M31/02—Apparatus for thermally treating combustion-air, fuel, or fuel-air mixture for heating
- F02M31/16—Other apparatus for heating fuel
- F02M31/18—Other apparatus for heating fuel to vaporise fuel
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
- F02P5/00—Advancing or retarding ignition; Control therefor
- F02P5/04—Advancing or retarding ignition; Control therefor automatically, as a function of the working conditions of the engine or vehicle or of the atmospheric conditions
- F02P5/045—Advancing or retarding ignition; Control therefor automatically, as a function of the working conditions of the engine or vehicle or of the atmospheric conditions combined with electronic control of other engine functions, e.g. fuel injection
Landscapes
- 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)
- Combustion Methods Of Internal-Combustion Engines (AREA)
Abstract
The invention provides a lean burn system and method for a spark-ignition engine. The method comprises the following steps: heating fuel oil, respectively injecting the fuel oil at two air inlet channels connected with an air cylinder to form flash boiling spray, wherein when the fuel oil is injected at the air inlet channels of the engine, an air inlet valve of the engine is always in an open state, or the air inlet valve of the engine is firstly in a closed state, then the air inlet valve of the engine is in an open state, and at a certain moment when the fuel oil is injected at the air inlet channels of the engine, a piston of the engine is positioned at an air inlet top dead center to form uniform thin mixed gas in the air cylinder; injecting fuel in a cylinder during a compression stroke of the engine; and is ignited at a time of 0 crank angle to 10 crank angle from the in-cylinder fuel injection end time. The invention can realize lean combustion with low oil consumption, low NOx concentration, less particulate matter emission and low cost.
Description
Technical Field
The invention relates to the technical field of engines, in particular to a lean combustion system and a lean combustion method for a spark ignition engine.
Background
A mixture having an air-fuel ratio larger than the stoichiometric air-fuel ratio is called a lean mixture, and combustion of the lean mixture in the engine is called lean combustion. By forming the thin mixed gas, the pumping loss is greatly reduced, the specific heat ratio of the mixed gas is improved, and the heat transfer loss is reduced. Therefore, lean burn is considered to be an effective means for improving the thermal efficiency and reducing the fuel consumption of gasoline engines.
Currently, lean combustion mainly includes three modes: the stratified charge injection method includes homogeneous charge compression ignition in which homogeneous charge is combusted in a compression self-ignition manner, stratified lean combustion in which the intake port injects fuel to form a stratified charge in a cylinder and combusts in a spark ignition manner, and stratified lean combustion in which the in-cylinder direct injection is used to form a stratified charge in the cylinder and combusts in a spark ignition manner. Although the in-cylinder direct injection stratified lean-burn system adopting in-cylinder direct injection stratified lean-burn enters the market, the system is only produced in mass production in a few automobile companies in the world so far, but is not popularized in large quantity, and mainly has the following problems:
1) in-cylinder direct injection stratified lean combustion systems tend to cause an increase in NOx concentration, and require a catalytic converter dedicated to NOx, which not only leads to an increase in cost, but also leads to a decrease in lean burn fuel economy and an increase in particulate matter emissions. Specifically, although the overall air-fuel ratio is low, in order to stabilize combustion, a rich mixture is formed around the spark plug so that the original NOx concentration generated by the first half combustion is high, and therefore, it is necessary to perform post-treatment of NOx. However, lean combustion makes the NOx conversion efficiency of low-cost and widely-spread three-way catalysts close to 0%. Therefore, an additional configuration of a NOx converter dedicated to Lean combustion, such as a Lean NOx Trap (LNT), is required. However, in addition to the increased cost of LNTs, the need to regenerate the catalyst through periodic enrichment not only compromises fuel consumption, thereby compromising the fuel saving potential of lean combustion, but also tends to increase particulate emissions.
2) The richer burning of the direct injection stratified lean combustion system around the spark plug leads to increased particulate emissions, which presents new challenges to meet the current increasingly stringent particulate emissions regulations worldwide.
3) The in-cylinder direct injection stratified lean combustion system is adopted, a piezoelectric crystal in-cylinder direct injection oil injector with higher use cost is needed, so that fuel oil with different pressures and different duration is injected in a grading manner, and the in-cylinder direct injection stratified lean combustion system is higher in cost.
Disclosure of Invention
The invention aims to provide a lean combustion system and a lean combustion method for a spark ignition engine, which aim to solve the problems of high NOx concentration, high particulate matter emission and high cost generated by the existing in-cylinder direct injection layered lean combustion system.
In order to solve the technical problem, the invention provides a lean combustion method for a spark-ignition engine, which comprises the steps of heating fuel oil, and then injecting the fuel oil at two air inlet channels connected with a cylinder in the engine to form flash boiling spray; when the fuel is injected at the air inlet channel of the engine, the air inlet valve of the engine is always in an open state, or the air inlet valve of the engine is firstly in a closed state and then is in an open state; at a certain moment of fuel injection at an air inlet channel of the engine, a piston of the engine is positioned at an air inlet top dead center so as to form uniform lean air-fuel mixture in a cylinder; performing direct in-cylinder injection on fuel in a compression stroke of the engine; and igniting at a time of 0 crank angle to 10 crank angle from the in-cylinder fuel injection end time.
Further, the fuel injection pressure of an air inlet channel of the engine is less than or equal to 1 MPa.
Further, the maximum temperature of the fuel after heating is 90 ℃ to 110 ℃.
Further, the fuel injection pressure of the in-cylinder direct injection is 20MPa or more and 150MPa or less, and the injection time period is 0.05ms or more and 0.3ms or less.
The invention also provides a lean combustion system for the spark-ignition engine, which comprises the engine, wherein the engine comprises at least one cylinder, and an in-cylinder direct injection injector and a spark plug which are arranged in each cylinder, the in-cylinder direct injection injector is used for injecting fuel in the cylinder in the compression stroke of the engine, the fuel injection pressure is more than or equal to 20MPa, and the fuel injection time length is less than or equal to 0.3 ms; the spark plug is ignited at a time of 0 crank angle to 10 crank angle degrees from the fuel injection end time of the direct injection injector.
Furthermore, the device also comprises an air inlet passage and an air passage oil sprayer, wherein each cylinder is at least connected with one air inlet passage, the air passage oil sprayer is arranged at the position of at least one air inlet passage, and the air passage oil sprayer is used for spraying fuel oil into the air inlet passage so as to form lean mixture in the cylinder.
Further, still include first oil supply pipeline and first oil rail, the one end and the air flue sprayer of first oil supply pipeline are connected, are provided with first oil rail on the first oil supply pipeline.
Further, the heating device is further included, and the air flue oil injector injects fuel oil heated by the heating device into the air inlet channel.
Further, the maximum temperature of the fuel injected by the port injector is 90 ℃ to 110 ℃.
Further, each cylinder is connected with two air inlet channels, and an air passage oil sprayer is arranged at each air inlet channel.
Further, the air inlet valve is arranged between the cylinder and the air inlet channel, and the air passage injector is arranged close to the air inlet valve.
Further, the fuel injection pressure of an air inlet channel of the engine is less than or equal to 1 MPa.
The device further comprises an exhaust valve, the cylinder is provided with a combustion chamber, the in-cylinder direct injection injector and the spark plug are arranged at the top of the combustion chamber, and the spark plug is close to the exhaust valve.
Further, when the direct injection injector injects fuel into the cylinder, the fuel injection pressure is less than or equal to 150MPa, and the fuel injection time is greater than or equal to 0.05 ms.
Compared with the prior art, the lean combustion system and the method for the ignition type engine provided by the invention have the advantages that the uniform lean mixture is formed in the cylinder, in the compression stroke of the engine, the fuel is subjected to in-cylinder direct injection, and ignition is carried out when the crank angle 0-10 degrees away from the end time of the fuel injected in the cylinder is reached, so that the area of an over-rich area of the fuel around a spark plug is reduced, the turbulence intensity around the spark plug is improved by in-cylinder high-pressure injection, the propagation speed of initial flame is accelerated, the uniform lean mixture is stably combusted, on one hand, the content of NOx formed in the combustion process due to the large-area over-rich area around the spark plug in the prior art is reduced, a catalytic converter specially aiming at the NOx is not required to be arranged on the gas discharged from the cylinder, the cost is saved, and the fuel is also saved, and reduces particulate matter emissions; on the other hand, since the fuel is a homogeneous lean mixture, particulate matter generated by lean combustion is reduced; on the other hand, the invention forms the uniform thin mixed gas without using the piezoelectric crystal oil injector which has high cost and is sensitive to oil products to form the layered thin mixed gas, thereby saving the cost.
Secondly, heating fuel oil firstly, and then injecting the heated fuel oil at an air inlet of the engine to form a lean mixture in the cylinder, wherein the heated fuel oil is easy to generate a flash boiling phenomenon during injection to form a flash boiling spray with a droplet diameter smaller than that of a conventional spray, so that evaporation, atomization and mixing with air of the droplets are facilitated, the lean mixture is more uniform, the uniform lean mixture enables combustion to be more sufficient and stable, and NOx and large particles generated therewith are reduced.
And secondly, each cylinder sprays fuel at two air inlet channels connected with the cylinder, so that the maximum flow of a single fuel injector in the invention can be smaller compared with the conventional scheme of one fuel injector in one cylinder, and the size of sprayed liquid drops is further reduced, thereby further improving the oil-gas mixture, enabling the uniform lean mixture to be combusted in a lean mode, saving oil, and reducing NOx and particulate matter emission generated by combustion.
Thirdly, because the invention adopts the mode that the heated fuel oil is injected at the two air inlet channels of the cylinder, the invention creates conditions for realizing the valve opening injection of all or part of the air inlet valves, namely when the fuel oil is injected at the air inlet channel of the engine, the air inlet valve of the engine is always in an opening state, or the air inlet valve of the engine is firstly in a closing state, then the air inlet valve of the engine is in an opening state, the fuel oil is favorable for forming flash boiling spray, and at a certain moment of injecting the fuel oil at the air inlet channel of the engine, the piston of the engine is positioned at an air inlet top dead center, so that the fuel oil injected at the air inlet channel can be mixed with the gas in the cylinder after the piston is positioned at the air inlet top dead center, the mixing time of the fuel oil and the gas is maximized, the mixing time of the flash boiling spray and the gas in the cylinder is maximized, and, the combustion of the lean mixture is more sufficient and stable, and the NOx and large particles generated by the combustion are further reduced.
Drawings
FIG. 1 is a schematic illustration of a lean burn system for a spark-ignition engine in an embodiment of the present disclosure;
FIG. 2 is a schematic diagram of the arrangement of the air intake passages of a single cylinder in one embodiment of the present invention;
FIG. 3 is a schematic diagram of a port injected fuel, in-cylinder injected fuel and ignition strategy for achieving lean burn in one embodiment of the present invention;
FIG. 4 is a schematic illustration of a port injected fuel, in-cylinder injected fuel and ignition strategy for achieving lean combustion in another embodiment of the present invention;
the reference numerals are explained below:
10-cylinder;
20-an air inlet channel;
30-a combustion chamber;
40-an exhaust valve;
50-a spark plug;
60-a first fuel supply system;
61-oil tank;
62-a first oil rail;
63-a first oil supply conduit;
64-a heating device;
65-gas passage fuel injector;
70-a second fuel supply system;
71-a second oil pump;
72-a second oil rail;
73-direct injection fuel injector;
74-a second oil supply conduit;
80-an intake valve;
a, oil injection time period of the air passage oil injector;
b, oil injection time interval of the direct injection oil injector in the cylinder;
c-ignition time of the spark plug;
delta-time interval of the injection end timing of the in-cylinder injector from the ignition timing.
Detailed Description
The lean burn system and method for a spark ignition engine according to the present invention will be described in further detail with reference to the accompanying drawings and embodiments. Advantages and features of the present invention will become apparent from the following description and from the claims. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is merely for the purpose of facilitating and distinctly claiming the embodiments of the present invention.
The present embodiment provides a lean combustion method for a spark-ignition engine, in which a lean mixture is formed in a cylinder, and fuel is injected in the cylinder during a compression stroke of the engine and ignited at a time of 0 crank angle to 10 crank angle from the time of end of injecting the fuel in the cylinder. Wherein all of the above injection and ignition strategies are completed within one cycle of the engine.
Because the lean mixture is formed in the cylinder, and the fuel is injected in the cylinder and is ignited timely (the fuel is ignited when the crank angle is 0-10 degrees away from the end time of the fuel injected in the cylinder) in the compression stroke of the engine, on one hand, the time for injecting the fuel in the cylinder is short, so that the fuel injection quantity is reduced, an over-rich area formed around a spark plug is greatly reduced, and most of the lean mixture in the cylinder can still be kept uniform; on the other hand, the high-pressure mode is adopted to spray fuel in the cylinder, the high-speed fuel spray improves the turbulence intensity around the spark plug, and the timely ignition is combined, so that the propagation speed of initial flame is accelerated, and the uniform lean mixture in the cylinder is stably combusted. Compared with the stratified lean combustion mode of in-cylinder direct injection in the prior art, firstly, the over-rich region formed around the spark plug is reduced and stable combustion can be realized, so that the content of NOx formed in the combustion process of the large-range over-rich region around the spark plug in the prior art is reduced, a catalytic converter specially aiming at NOx is not required to be arranged on the gas discharged from the cylinder, and the cost is saved; secondly, the over-rich area is reduced, uniform lean mixed gas is formed in the cylinder, and the fuel consumption is stable, so that the fuel oil is combusted more fully, and the particulate matter emission is greatly reduced; thirdly, because the uniform thin mixed gas is formed, the piezoelectric crystal oil injector which is high in cost and sensitive to oil products is not needed to be used for forming the layered thin mixed gas, the conventional oil injector which is already produced in large batch can be used, and the cost is saved.
In a preferable scheme, when the fuel is subjected to in-cylinder direct injection, the injection pressure of the fuel is more than or equal to 20MPa and less than or equal to 150MPa, and the injection time of the fuel in-cylinder injection is 0.05ms to 0.3ms, so that lean combustion is more stable, and the content of NOx generated by combustion and the emission of particulate matters are reduced.
In order to further reduce the cost, in the embodiment, fuel is injected at an air inlet of the engine to form a lean mixture in the cylinder, and the fuel injected by the air inlet can be a common air inlet injector.
In order to enable the fuel injected by the air inlet passage to form a more uniform lean mixture after entering the cylinder and further reduce the content of NOx and particulate matters after lean combustion, in the embodiment, the fuel is heated first, and then the heated fuel is injected at the air inlet passage of the engine. The heated fuel is very easy to flash and boil when being injected. The droplet diameter of the flash boiling spray formed after the flash boiling of the fuel is smaller than that of the conventional spray, so that the evaporation, atomization and mixing with air of the droplets are facilitated, the lean mixed gas is more uniform, the combustion of the lean mixed gas is more sufficient and more stable due to the uniform mixed gas, and the NOx and large particle matters generated therewith are reduced. For example, the maximum temperature after heating is 90 ℃ to 110 ℃ before the fuel is injected at the intake port. Specifically, a first fuel supply system is arranged in a fuel supply system of the engine, the first fuel supply system comprises a first fuel supply pipeline, a first fuel rail and a gas channel fuel injector, the gas channel fuel injector is connected with the first fuel rail through the first fuel supply pipeline, and fuel heating can be achieved by heating the first fuel rail. The first fuel rail is used for storing fuel, and simultaneously, pressure fluctuation generated by an oil way of the first fuel supply system is restrained, so that the pressure of the first fuel supply system is stable.
In addition, in the embodiment, the lean mixture in the cylinder can be more uniform by setting the fuel injection time of the fuel at the air inlet passage and the opening time of the valve. For example, referring to FIG. 3, the intake valves are all in an open state when fuel is injected in the intake port of the engine during a single cycle of operation of the engine, i.e., the intake valves are in the intake valve lift, or, referring to FIG. 4, the intake valves are first in a closed state and then the intake valves are in an open state, and at some point in time when fuel is injected in the intake port of the engine, the piston of the engine is at intake top dead center. The air inlet valve is in an open state firstly when injecting fuel, and at a certain moment when an air inlet channel of the engine injects fuel, a piston of the engine is positioned at an air inlet top dead center, and the air inlet valve is in a closed state firstly when injecting fuel, and a rear air inlet valve is in an open state, at a certain moment when the air inlet channel of the engine injects fuel, a partial valve opening injection strategy that the piston of the engine is positioned at an air inlet top dead center, the two injection strategies enable the spray which is subjected to flashing and good atomization to directly enter the cylinder for mixture preparation at the end of an exhaust stroke or at the beginning of an intake stroke, rather than the conventional injection to the surface of the air inlet, the fuel is evaporated and atomized by only depending on the heating of the air inlet and the heating and impact of the returned exhaust gas, therefore, the lean mixture in the cylinder is mixed more uniformly, and the increase of particulate matter emission caused by the fact that fuel oil touches the surface of an air passage to form a large amount of unburned oil films is avoided.
In the embodiment, the mode that the fuel injected in the air inlet channel enters the cylinder can be optimized, and the fuel can be further ensured to form more uniform mixed gas after entering the cylinder. For example, fuel is injected separately in two intake ports connected to a single cylinder. Compared with the mode of injecting fuel in only one air inlet channel of the cylinder, the maximum flow of the fuel in a single air inlet channel is reduced, so that fuel droplets with smaller sizes are formed, and the lean mixture is more uniform.
In the present embodiment, the homogeneous lean mixture is the stratified lean mixture as compared to the stratified lean mixture of the direct-injection stratified lean combustion system in the related art.
For another example, fuel may be injected in the intake passage near the intake valve, and in particular, fuel may be injected in the intake passage near the intake valve. Compared with the prior art, the fuel is injected into the air inlet passage, the fuel is evaporated and atomized only by means of heating of the air inlet passage and heating and impact of backflow waste gas, and the fuel needs to be injected at the moment when the air inlet valve is closed.
In the present embodiment, the injection pressure of the fuel injected in the intake passage of the engine is preferably 1Mpa or less. Therefore, the conventional oil sprayer can be adopted for oil spraying in the air inlet passage, and the high-pressure oil sprayer, the second oil pump corresponding to the high-pressure oil sprayer and the second oil rail are not required to be arranged, so that the cost is reduced.
By last knowing, this embodiment forms the spraying of sudden boiling through carrying out fuel injection at the intake duct, and the mode and the time that the reasonable spraying that sets up gets into the cylinder to form even thin gas mixture, combine to set up oil spout mode and oil spout time in the cylinder, and set up reasonable some moments, realized high-efficient stable thin burning. The lean combustion method for a spark-ignition engine provided in the embodiment is applied to at least one cylinder of the engine, and a lean combustion system for implementing the lean combustion method for a spark-ignition engine is described below by taking combustion of one cycle in a single cylinder of the engine as an example. Referring to fig. 1, a lean burn system for a spark-ignition engine includes: a cylinder 10, an intake passage 20, a first fuel supply system 60, and a second fuel supply system 70. The intake passage 20 is connected to the cylinder 10 to supply air to the cylinder 10. The first fuel supply system 60 supplies fuel to the cylinder 10 by injecting fuel in the intake passage 20. The second fuel supply system 70 supplies fuel to the cylinder 10 by directly injecting fuel into the cylinder 10.
The first fuel supply system 60 includes a first tank 61, a first fuel rail 62, a first fuel supply pipe 63, a heating device 64, and a rail injector 65. The gas passage injector 65 is connected to the first oil rail 62 through a first oil supply pipe 63, and the first oil rail 62 is connected to the first oil tank 61 through the first oil supply pipe 63. A port injector 65 is provided at the intake passage 20 for injecting fuel into the intake passage 20. The injection pressure of the fuel injected by the port injector 65 is preferably 1MPa or less. The port injector 65 may be a solenoid-driven multi-port injector for a conventional port-injection engine, and preferably a multi-port swirl injector (SwirlInjector) is used. The first fuel rail 62 is used to store fuel while suppressing pressure fluctuations due to the injection of fuel from the first fuel tank 61 and the pilot fuel injector 65, ensuring pressure stability in the first fuel supply system 60. The heating device 64 is used to heat the first fuel rail 62, and fuel heating is achieved so that the maximum temperature of the fuel injected from the gas passage injector 65 is 90 ℃ to 110 ℃. Wherein the heating device 64 may also heat the fuel by heating the first fuel supply pipe 63 connected to the port injector 65. Of course, the injection pressure of the fuel injected by the gas passage injector 65 may be larger than 1MPa, but the corresponding gas passage injector 65 needs to adopt an injector suitable for high-pressure injection and a high-pressure fuel supply system provided for supplying fuel to the injector, which is relatively high in cost.
The second fuel supply system 70 includes a second oil tank (not shown in the drawings), a second oil pump 71, a second oil rail 72, a second oil supply pipe 74, and an in-cylinder direct injection injector 73. The in-cylinder direct injection injector 73 is connected to a second oil rail 72 through a second oil supply line 74, the second oil rail 72 is connected to the second oil pump 71 through the second oil supply line 74, and the second oil pump 71 is connected to the second oil tank 61 through the second oil supply line 74. The in-cylinder direct injection injector 73 is configured to inject high-pressure fuel having a fuel injection pressure of 20MPa or more into the cylinder 10 near the ignition timing in the latter stage of the compression stroke, and the injection time period is 0.3ms or less. For example, the in-cylinder direct injection injector 73 is an electromagnetic valve-driven inward-opening ring multi-orifice injector used in a conventional in-cylinder direct injection gasoline engine. The second fuel rail 72 is used to store fuel while suppressing pressure fluctuations due to injection from the second oil pump 71 and the direct in-cylinder injector 73, ensuring pressure stability in the second fuel supply system 70.
It should be understood that the first fuel supply system 60 and the second fuel supply system 70 may each include a tank, or the second fuel supply system 70 and the first fuel supply system 60 may share a tank (i.e., share the first tank 61) as shown in fig. 1 to save costs.
Wherein the lean burn system for a spark-ignition engine further includes an exhaust valve 40 and an ignition plug 50, the cylinder includes a combustion chamber 30, an in-cylinder direct injection injector 73 and the ignition plug 50 are both disposed at the top of the combustion chamber 30, and the ignition plug 50 is closer to the exhaust valve 40 than the in-cylinder direct injection injector 73. The ignition plug 50 ignites at a time of 0 crank angle degrees to 10 crank angle degrees from the time of the end of fuel injection into the cylinder 10. Of course, the ignition plug 50 and the in-cylinder direct injector 73 may be provided at the top of the combustion chamber 30, and the in-cylinder direct injector 73 may be located closer to the exhaust valve 40 than the ignition plug 50.
A single cylinder 10 of the engine generally includes two intake ports 20, and as shown with reference to fig. 2, a port injector 65 may be provided at both intake ports 20. In the present embodiment, the lean combustion system for a spark ignition engine further includes an intake valve 80, the intake valve 80 being disposed between the cylinder 10 and the intake passage 20, and the port injector 65 being disposed near the intake valve 80.
The operation of the lean burn system for a spark ignition engine provided in the present embodiment will be described with reference to fig. 1 and 2, taking the operation of the engine in one operation cycle as an example.
Referring to fig. 3, one operating cycle of the engine includes: an expansion stroke, an exhaust stroke, an intake stroke, and a compression stroke. The compression top dead center and the air inlet top dead center correspond to the piston of the engine positioned at the top dead center of the cylinder, and the bottom dead center corresponds to the piston of the engine positioned at the bottom dead center of the cylinder. The exhaust valve lift refers to a state in which the exhaust valve is open, and the intake valve lift refers to a state in which the intake valve is open. In the intake valve lift, the air passage injector 65 injects fuel (preferably heated fuel) in the air passage 20 when the piston of the engine is located near the top dead center of the engine, that is, in the fuel injection period a of the air passage injector, and the fuel injection pressure is less than or equal to 1MPa, after the fuel is injected, a flash boiling phenomenon occurs to form flash boiling spray, and the flash boiling spray enters the cylinder 10 along with the air flow to form uniform lean air mixture. In the compression stroke, the in-cylinder direct injector 73 injects fuel into the cylinder 10 at a fuel injection pressure of 20MPa or more for 0.3ms or less during the injection period B of the in-cylinder direct injector, and the ignition plug 50 ignites at the plug ignition timing C after 0 crank angle degrees to 10 crank angle degrees at the injection end timing of the in-cylinder direct injector 73. Wherein a time interval from an injection end timing of the in-cylinder injector to an ignition timing is defined as Δ in crank angle units. Further, referring to fig. 4, the injection period of the port injector 65 may also start injecting fuel from when the intake valve 80 is closed until the injection of fuel is finished after the intake valve 80 is opened for a certain period of time.
In summary, the lean combustion system and method for a spark-ignition engine provided by the embodiment inject heated fuel in an air inlet of the engine, so that a flash boiling phenomenon occurs when the fuel is injected, and the way and time for spraying into a cylinder are reasonably set, so that the fuel enters the cylinder to form a uniformly mixed lean mixture, and the fuel oil with large injection pressure and short injection time is injected in the cylinder in the later period of the compression stroke of the engine, and is ignited at a proper time, so that the area of an over-rich area formed around the spark plug is greatly reduced, stable fuel consumption can be realized, thereby reducing the amount of NOx formed during combustion in the prior art due to the large area of the rich zone around the spark plug, the gas discharged from the cylinder does not need to be provided with a catalytic converter specially aiming at NOx, so that the cost is saved while the oil is saved. In addition, the area of the over-rich area is reduced, and the fuel oil is combusted more fully due to uniform lean mixture and stable combustion in the cylinder, so that the emission of particulate matters is greatly reduced. In addition, the piezoelectric crystal fuel injector which is high in cost and sensitive to oil products does not need to be used in the embodiment, and a conventional fuel injector which is already produced in large batch is used, so that the cost is further saved.
The above description is only for the purpose of describing the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention, and any variations and modifications made by those skilled in the art based on the above disclosure are within the scope of the appended claims.
Claims (14)
1. A lean-burn method for a spark-ignition engine, comprising:
heating fuel oil, and then injecting the fuel oil at two air inlet channels connected with a cylinder in an engine to form flash boiling spray;
when the fuel is injected at the air inlet channel of the engine, the air inlet valve of the engine is always in an open state, or the air inlet valve of the engine is firstly in a closed state and then is in an open state;
at a certain moment when fuel is injected at an air inlet channel of the engine, a piston of the engine is positioned at an air inlet top dead center;
performing direct in-cylinder injection on fuel in a compression stroke of the engine; and
and is ignited at a time of 0 crank angle to 10 crank angle from the in-cylinder fuel injection end time.
2. The lean combustion method for a spark ignition engine according to claim 1, wherein a fuel injection pressure of an intake port of the engine is 1MPa or less.
3. The lean combustion method for a spark ignition engine according to claim 1, wherein the maximum temperature after the fuel is heated is 90 ℃ to 110 ℃.
4. The lean combustion method for a spark ignition engine according to claim 1, wherein a fuel injection pressure of the in-cylinder direct injection is 20MPa or more and 150MPa or less, and a fuel injection period is 0.05ms or more and 0.3ms or less.
5. A lean combustion system for a spark ignition engine, for use in the lean combustion method for a spark ignition engine according to any one of claims 1 to 4, comprising an engine including at least one cylinder, and an in-cylinder direct injection injector and an ignition plug provided in each cylinder, characterized in that the in-cylinder direct injection injector is configured to inject fuel in the cylinder in a compression stroke of the engine, a fuel injection pressure is 20MPa or more, and a fuel injection time period is 0.3ms or less; the spark plug is ignited at a time of 0 crank angle to 10 crank angle degrees from the fuel injection end time of the direct injection injector.
6. The lean combustion system for a spark-ignition engine according to claim 5, further comprising an intake port and a port injector, wherein at least one intake port is connected to each cylinder, and a port injector is provided at least one intake port for injecting fuel into the intake port to form a lean mixture in the cylinder.
7. The lean burn system for a spark ignition engine as claimed in claim 6, further comprising a first oil supply conduit having one end connected to the gas passage injector and a first oil rail provided thereon.
8. The lean burn system for a spark ignition engine as claimed in claim 6, further comprising a heating means, and the port injector injects fuel heated by the heating means into the intake port.
9. The lean burn system for a spark ignition engine according to claim 6, wherein the maximum temperature of the fuel injected by the port injector is 90 ℃ to 110 ℃.
10. The lean burn system for a spark ignition engine of claim 6 wherein two intake ports are connected to each cylinder and a port injector is provided at each intake port.
11. The lean burn system for a spark ignition engine of claim 6, further comprising an intake valve disposed between the cylinder and the intake port, the port injector being disposed proximate the intake valve.
12. The lean burn system for a spark ignition engine of claim 6, wherein a fuel injection pressure of an intake port of the engine is 1MPa or less.
13. The lean-burn combustion system for a spark-ignition engine according to claim 5, further comprising an exhaust valve, wherein the cylinder has a combustion chamber, and wherein the in-cylinder direct-injection injector and the ignition plug are disposed at a top portion of the combustion chamber, and wherein the ignition plug is located near the exhaust valve.
14. The lean combustion system for a spark ignition engine as claimed in any one of claims 5 to 13, characterized in that when the direct injection injector injects fuel in the cylinder, the fuel injection pressure is 150MPa or less and the injection time period is 0.05ms or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710144104.3A CN108571392B (en) | 2017-03-10 | 2017-03-10 | Lean burn system and method for spark-ignition engine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710144104.3A CN108571392B (en) | 2017-03-10 | 2017-03-10 | Lean burn system and method for spark-ignition engine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108571392A CN108571392A (en) | 2018-09-25 |
| CN108571392B true CN108571392B (en) | 2020-10-09 |
Family
ID=63578087
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710144104.3A Active CN108571392B (en) | 2017-03-10 | 2017-03-10 | Lean burn system and method for spark-ignition engine |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108571392B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111042955B (en) * | 2018-10-12 | 2022-03-15 | 联合汽车电子有限公司 | Engine system and combustion method |
| JP7232566B2 (en) * | 2019-05-24 | 2023-03-03 | 日産自動車株式会社 | CONTROL METHOD AND CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE |
| CN112555017B (en) * | 2019-09-26 | 2022-06-28 | 联合汽车电子有限公司 | Lean combustion system, lean combustion engine and lean combustion method |
| CN110748918B (en) * | 2019-10-24 | 2024-03-29 | 南京航空航天大学 | Flash boiling type evaporation cavity flame stabilizer applicable to low temperature and low pressure |
| CN115217615B (en) * | 2022-04-06 | 2023-08-15 | 广州汽车集团股份有限公司 | Scavenging device and scavenging method |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004044453A (en) * | 2002-07-10 | 2004-02-12 | Toyota Motor Corp | Fuel injection control device for internal combustion engine |
| JP2006161580A (en) * | 2004-12-02 | 2006-06-22 | Toyota Motor Corp | Internal combustion engine |
| JP2007255211A (en) * | 2006-03-20 | 2007-10-04 | Toyota Motor Corp | Control device for compression ignition internal combustion engine |
| CN101289964A (en) * | 2007-04-20 | 2008-10-22 | 日产自动车株式会社 | Internal combustion engine and combustion method of the same |
| CN102159820A (en) * | 2007-08-09 | 2011-08-17 | 丰田自动车株式会社 | Fuel injection control system and fuel injection control method for spark-ignition internal combustion engine |
| JP2012207631A (en) * | 2011-03-30 | 2012-10-25 | Mazda Motor Corp | Control device of spark ignition type gasoline engine |
Family Cites Families (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5894832A (en) * | 1996-07-12 | 1999-04-20 | Hitachi America, Ltd., Research And Development Division | Cold start engine control apparatus and method |
| JP2000283007A (en) * | 1999-03-26 | 2000-10-10 | Honda Motor Co Ltd | Internal combustion engine |
| JP2005054615A (en) * | 2003-08-08 | 2005-03-03 | Hitachi Ltd | Fuel supply system and fuel supply method of cylinder injection engine |
| JP4751584B2 (en) * | 2004-05-26 | 2011-08-17 | 株式会社日本自動車部品総合研究所 | Control device for internal combustion engine |
| JP2008106737A (en) * | 2006-09-25 | 2008-05-08 | Toyota Motor Corp | Premixed compression auto-ignition gasoline engine |
| JP4716198B2 (en) * | 2008-01-28 | 2011-07-06 | トヨタ自動車株式会社 | Fuel supply device for internal combustion engine |
| JP5321844B2 (en) * | 2010-03-25 | 2013-10-23 | 三菱自動車工業株式会社 | Fuel injection control device for internal combustion engine |
| JP5126421B2 (en) * | 2010-03-26 | 2013-01-23 | トヨタ自動車株式会社 | Combustion control device for internal combustion engine |
| WO2012014288A1 (en) * | 2010-07-27 | 2012-02-02 | トヨタ自動車株式会社 | Internal combustion engine controller |
| JP5500102B2 (en) * | 2011-02-24 | 2014-05-21 | マツダ株式会社 | Control device for spark ignition gasoline engine |
| JP5533732B2 (en) * | 2011-02-24 | 2014-06-25 | マツダ株式会社 | Control device for spark ignition gasoline engine |
| DE102011007327B4 (en) * | 2011-04-13 | 2024-01-18 | Robert Bosch Gmbh | Injection device and internal combustion engine |
| JP5516804B2 (en) * | 2013-07-25 | 2014-06-11 | トヨタ自動車株式会社 | Control device for internal combustion engine |
| JP6414130B2 (en) * | 2016-04-27 | 2018-10-31 | トヨタ自動車株式会社 | Control device for internal combustion engine |
-
2017
- 2017-03-10 CN CN201710144104.3A patent/CN108571392B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004044453A (en) * | 2002-07-10 | 2004-02-12 | Toyota Motor Corp | Fuel injection control device for internal combustion engine |
| JP2006161580A (en) * | 2004-12-02 | 2006-06-22 | Toyota Motor Corp | Internal combustion engine |
| JP2007255211A (en) * | 2006-03-20 | 2007-10-04 | Toyota Motor Corp | Control device for compression ignition internal combustion engine |
| CN101289964A (en) * | 2007-04-20 | 2008-10-22 | 日产自动车株式会社 | Internal combustion engine and combustion method of the same |
| CN102159820A (en) * | 2007-08-09 | 2011-08-17 | 丰田自动车株式会社 | Fuel injection control system and fuel injection control method for spark-ignition internal combustion engine |
| JP2012207631A (en) * | 2011-03-30 | 2012-10-25 | Mazda Motor Corp | Control device of spark ignition type gasoline engine |
Also Published As
| Publication number | Publication date |
|---|---|
| CN108571392A (en) | 2018-09-25 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6845746B2 (en) | Internal combustion engine with injection of gaseous fuel | |
| CN101571069B (en) | Dual-fuel combustion system for internal combustion engines | |
| CN109441626B (en) | Dual-fuel engine combustion organization method adopting main and auxiliary fuel injectors and manifold for multiple injection | |
| CN108571392B (en) | Lean burn system and method for spark-ignition engine | |
| US20130104850A1 (en) | Multi-fuel pre-mixed combustion system of internal combustion engine | |
| CN109296446B (en) | Combustion organization method of diesel micro-injection ignition natural gas engine with natural gas high and low pressure mixed injection and pre-combustion chamber | |
| CN109209656B (en) | Combustion organization method for natural gas engine | |
| CN109209655B (en) | A dual-fuel engine combustion system and combustion method | |
| CN110318891B (en) | Multi-mode combustion organization method for natural gas/diesel dual-fuel engine | |
| US20140299105A1 (en) | Methods for Low Temperature Combustion and Engines Using the Same | |
| CN101975118A (en) | Method and device for controlling emission of passenger car engine based on double jetting of fuels in cylinder | |
| CN108561233A (en) | A kind of diesel/natural gas dual-fuel engine emission control strategy | |
| US20190170077A1 (en) | Combustion control method and combustion control system with variable excess air coefficient for gasoline engine | |
| CN109386396B (en) | Combustion control method for natural gas engine | |
| CN104989539A (en) | Internal combustion engine for direct injection of double-gas fuel in cylinder under EGR condition and control method | |
| CN109026412A (en) | A kind of dual fuel engine lean burn method for organizing | |
| CN102619636B (en) | A kind of petrol engine energy-saving and emission-reduction combustion method | |
| CN112145281A (en) | Fuel preparation and supply system and method for active precombustion chamber | |
| CN105673281B (en) | In a kind of gas/liquid double fuel cylinder/cylinder outer pair of injection apparatus and control method | |
| CN116608071A (en) | Jet ignition type methanol engine combustion system | |
| CN108194207B (en) | Variable compression ratio system of internal combustion engine and internal combustion engine | |
| CN102996223A (en) | Premixed combustion system of diesel engine | |
| CN112555017B (en) | Lean combustion system, lean combustion engine and lean combustion method | |
| CN204961094U (en) | Two gaseous fuel's of direct injection internal -combustion engine under EGR condition | |
| CN109184926B (en) | A dual-needle valve fuel injector-based dual-fuel engine combustion device and method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |