CN106930846B - Control method and system of multi-stroke cycle engine and vehicle - Google Patents

Control method and system of multi-stroke cycle engine and vehicle Download PDF

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Publication number
CN106930846B
CN106930846B CN201511019520.8A CN201511019520A CN106930846B CN 106930846 B CN106930846 B CN 106930846B CN 201511019520 A CN201511019520 A CN 201511019520A CN 106930846 B CN106930846 B CN 106930846B
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stroke
engine
compression
expansion
stroke cycle
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CN106930846A (en
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裴俊杨
王义夫
张猛
杨中华
乔佳伟
夏培生
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Great Wall Motor Co Ltd
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Great Wall Motor Co Ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D35/00—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for
    • F02D35/0007—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for using electrical feedback
    • 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
    • F02B75/00—Other engines
    • F02B75/02—Engines characterised by their cycles, e.g. six-stroke
    • 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
    • F02B75/00—Other engines
    • F02B75/12—Other methods of operation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/60—Input parameters for engine control said parameters being related to the driver demands or status
    • F02D2200/606—Driving style, e.g. sporty or economic driving

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Output Control And Ontrol Of Special Type Engine (AREA)

Abstract

The invention provides a control method and a control system of a multi-stroke cycle engine and a vehicle, wherein the method comprises the following steps: receiving a driving mode selection signal and fault information of an engine; judging whether a multi-stroke cycle mode entering condition is met or not according to the driving mode selection signal and the fault information; if yes, matching the corresponding multi-stroke cycle mode and stroke combination according to the operation working condition of the engine and the engine operation state information; the engine is controlled based on the determined multi-stroke cycle mode and stroke combination. The method can effectively improve the fuel economy of the engine under a plurality of operating conditions and reduce the emission of tail gas pollutants.

Description

Control method and system of multi-stroke cycle engine and vehicle
Technical Field
The invention relates to the technical field of automobiles, in particular to a control method and a control system of a multi-stroke cycle engine and a vehicle.
Background
At present, an internal combustion engine (such as a gasoline engine) for a vehicle is generally a four-stroke cycle internal combustion engine, namely four strokes of air intake, compression, power generation and air exhaust. The thermal energy of the combustion explosion of the fuel in the combustion chamber is converted into the rotational kinetic energy output outwards through the crank-link mechanism, but in each working cycle, the kinetic energy can be effectively output for less than one fourth of the time, and heat loss and mechanical loss in the whole four-stroke cycle exist all the time, and especially 30% -40% of the thermal energy is lost in a ventilation stage (during exhaust and intake strokes). The heat loss of the present four-stroke cycle internal combustion engine is large.
Especially, under the partial load operation of the internal combustion engine, the heat energy loss is very large, and further, the oil consumption is high, and the emission is poor.
Disclosure of Invention
In view of the above, the present invention is directed to a control method for a multi-stroke cycle engine, which can effectively improve the fuel economy of the engine in multiple operating conditions and reduce the emission of exhaust pollutants.
In order to achieve the purpose, the technical scheme of the invention is realized as follows:
a control method of a multi-stroke cycle engine including at least an intake stroke, a compression stroke, a power stroke, and an exhaust stroke, the number of strokes of the multi-stroke cycle engine being N, the N being an even number equal to or greater than four, a first stroke in the multi-stroke cycle mode being an intake stroke, a second stroke being a compression stroke, an N-th stroke being an exhaust stroke, and the third stroke through (N-1) th stroke being obtained by combining the compression stroke and the power stroke, the control method comprising the steps of: receiving a driving mode selection signal and fault information of an engine; judging whether a multi-stroke cycle mode entering condition is met or not according to the driving mode selection signal and the fault information; if yes, matching a corresponding multi-stroke cycle mode according to the operation working condition of the engine and the engine operation state information; controlling the engine according to the determined multi-stroke cycle mode.
Further, the multi-stroke cycle engine further comprises an air suction expansion stroke and an expansion stroke, wherein the expansion stroke is a process that an air inlet valve and an exhaust valve are closed and a piston descends from a top dead center; the suction expansion stroke refers to a process of opening an intake valve at a proper time to suck a predetermined amount of air or air mixture in an expansion process in which a piston descends from a top dead center, and the third stroke to the (N-1) th stroke are obtained by combining the compression stroke, the power stroke, the suction expansion stroke and the expansion stroke, wherein if a previous stroke of the third stroke to the (N-1) th stroke is the power stroke, the expansion stroke or the suction expansion stroke, a subsequent stroke immediately following the previous stroke is the compression stroke; a descendant stroke immediately after the compression stroke is one of a power stroke, an expansion stroke, and a suction-expansion stroke if a previous stroke of the third to (N-1) th strokes is a compression stroke; wherein the (N-1) th stroke is a power stroke or an expansion stroke.
Further, the operation conditions of the engine comprise a starting condition, a warming condition and a normal operation condition.
Further, the method also comprises the following steps: and when it is judged that the multi-stroke cycle mode entry condition is not satisfied, controlling the engine according to a conventional four-stroke cycle mode.
Further, the engine operating state information includes engine water temperature, engine speed, engine load signal, engine timing signal/top dead center signal, in-cylinder pressure signal, knock sensor signal, intake air flow rate, oxygen sensor signal.
Compared with the prior art, the control method of the multi-stroke cycle engine has the following advantages:
the control method of the multi-stroke cycle engine can effectively improve the fuel economy of the engine in a plurality of operating conditions and reduce the emission of tail gas pollutants.
Another object of the present invention is to provide a control system for a multi-stroke cycle engine, which can effectively improve the fuel economy of the engine in multiple operating conditions and reduce the emission of exhaust pollutants.
In order to achieve the purpose, the technical scheme of the invention is realized as follows:
a control system of a multi-stroke cycle engine including at least an intake stroke, a compression stroke, a power stroke, and an exhaust stroke, the number of strokes of the multi-stroke cycle engine being N, the N being an even number equal to or greater than four, a first stroke in the multi-stroke cycle mode being an intake stroke, a second stroke compression stroke, an nth stroke being an exhaust stroke, and third to (N-1) th strokes being obtained by combining the compression stroke and the power stroke, the control system comprising: the receiving module is used for receiving the driving mode selection signal and fault information of the engine; the judging module is used for judging whether the multi-stroke cycle mode entering condition is met or not according to the driving mode selection signal and the fault information; the multi-stroke cycle mode determining module is used for matching the corresponding multi-stroke cycle mode and stroke combination according to the operation condition and the operation state information of the engine when the judging module judges that the multi-stroke cycle mode entering condition is met; a control module controls the engine based on the determined multi-stroke cycle mode and the combination of strokes.
Further, the multi-stroke cycle engine further comprises an air suction expansion stroke and an expansion stroke, wherein the expansion stroke is a process that an air inlet valve and an exhaust valve are closed and a piston descends from a top dead center; the suction expansion stroke refers to a process of opening an intake valve at a proper time to suck a predetermined amount of air or air mixture in an expansion process in which a piston descends from a top dead center, and the third stroke to the (N-1) th stroke are obtained by combining the compression stroke, the power stroke, the suction expansion stroke and the expansion stroke, wherein if a previous stroke of the third stroke to the (N-1) th stroke is the power stroke, the expansion stroke or the suction expansion stroke, a subsequent stroke immediately following the previous stroke is the compression stroke; a descendant stroke immediately after the compression stroke is one of a power stroke, an expansion stroke, and a suction-expansion stroke if a previous stroke of the third to (N-1) th strokes is a compression stroke; wherein the (N-1) th stroke is a power stroke or an expansion stroke.
Further, the operation conditions of the engine comprise a starting condition, a warming condition and a normal operation condition.
Further, the method also comprises the following steps: and when it is judged that the multi-stroke cycle mode entry condition is not satisfied, controlling the engine according to a conventional four-stroke cycle mode.
The control system of the multi-stroke cycle engine and the control method of the multi-stroke cycle engine have the same advantages compared with the prior art, and are not described again.
Another object of the present invention is to provide a vehicle, which can effectively improve the fuel economy of the engine in multiple operating conditions and reduce the emission of exhaust pollutants.
In order to achieve the purpose, the technical scheme of the invention is realized as follows:
a vehicle is provided with the control system of the multi-stroke cycle engine as described in the above embodiment.
The advantages of the vehicle and the control system of the multi-stroke cycle engine are the same compared with the prior art, and the detailed description is omitted.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
FIG. 1 is a flow chart of a method of controlling a multi-stroke cycle engine according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of six strokes in a control method of a multi-stroke cycle engine according to another embodiment of the present invention;
FIG. 3 is a flow chart illustrating a start-up condition in a control method for a multi-stroke cycle engine according to an embodiment of the present invention;
FIG. 4 is a flow chart illustrating a warm-up condition in a method of controlling a multi-stroke cycle engine according to an embodiment of the present invention;
fig. 5 is a block diagram of a control system of an engine according to an embodiment of the present invention;
FIG. 6 is a flow chart of a method of mode switching for a multi-stroke cycle engine according to an embodiment of the present invention;
FIG. 7 is a flowchart illustrating transition switching between multi-cycle modes in a mode switching method of a multi-cycle engine according to an embodiment of the present invention;
FIG. 8 is a block diagram of a mode switching system for a multi-stroke cycle engine according to an embodiment of the present invention;
FIG. 9 is a flowchart of a method of controlling a multi-cycle gasoline engine according to an embodiment of the present invention;
FIG. 10 is a block diagram of a control system for a multi-cycle gasoline engine according to an embodiment of the present invention;
FIG. 11 is a flow chart of a method of controlling a multi-cycle dual fuel engine in accordance with an embodiment of the present invention;
fig. 12 is a block diagram of a control system of a multi-cycle dual-fuel engine according to an embodiment of the present invention.
Description of reference numerals:
the control system 500 of the multi-stroke cycle engine, the receiving module 510, the determining module 520, the multi-stroke cycle mode determining module 530, the control module 540, the mode switching system 800 of the multi-stroke cycle engine, the first determining module 810, the second determining module 820, the switching module 830, the control system 1100 of the multi-stroke cycle gasoline engine, the fuel injection module 1010, the ignition module 1020, the control system 1200 of the multi-stroke cycle dual-fuel engine, the first fuel injection module 1210, and the first ignition module 1220.
Detailed Description
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.
FIG. 1 is a flow chart of a method of controlling a multi-stroke cycle engine according to one embodiment of the present invention.
Before describing the control method of the multi-stroke cycle engine of the embodiment of the present invention, the multi-stroke cycle engine will be described first. The multi-stroke cycle engine at least comprises an intake stroke, a compression stroke, a power stroke and an exhaust stroke, wherein the stroke number of the multi-stroke cycle engine is N, N is an even number which is more than or equal to four, the first stroke in the multi-stroke cycle mode is an intake stroke, the second stroke is a compression stroke, the Nth stroke is an exhaust stroke, and the third stroke to the (N-1) th stroke are obtained by combining the compression stroke and the power stroke.
In particular, a multi-stroke cycle engine may also be referred to as a hybrid stroke cycle engine or a variable stroke cycle engine. The number of strokes of a multi-stroke cycle engine may be varied, for example: four-stroke, six-stroke, eight-stroke, ten-stroke, etc. The multi-stroke cycle engine may be operated in a four-stroke cycle mode, a six-stroke cycle mode, an eight-stroke cycle mode, a ten-stroke cycle mode, and so on. In addition, the stroke types, whether four-stroke, six-stroke, eight-stroke, or ten-stroke, include at least four stroke types, such as: the engine comprises an intake stroke, a compression stroke, a power stroke and an exhaust stroke, and in addition, whether the multi-stroke cycle engine adopts a four-stroke cycle mode operation, a six-stroke cycle mode operation, an eight-stroke cycle mode operation or a ten-stroke cycle mode operation, in the process of one cycle, the first stroke is an intake stroke, and the last stroke is an exhaust stroke.
The stroke type of the multi-stroke cycle engine may include an intake expansion stroke and an expansion stroke, in addition to the four stroke types described above, wherein the expansion stroke is a process in which the intake and exhaust valves are closed and the piston descends from the top dead center. The suction expansion stroke refers to a process of opening an intake valve timely to suck a preset amount of air or mixture in the expansion process of descending the piston from the top dead center, and a third stroke to the (N-1) th stroke are obtained by combining a compression stroke, a power stroke, the suction expansion stroke and an expansion stroke, wherein if the previous stroke from the third stroke to the (N-1) th stroke is the power stroke, the expansion stroke or the suction expansion stroke, the next stroke immediately following the previous stroke is the compression stroke; a descendant stroke immediately after the compression stroke is one of a power stroke, an expansion stroke, and a suction-expansion stroke if a previous stroke of the third to (N-1) th strokes is the compression stroke; wherein the (N-1) th stroke is a power stroke or an expansion stroke.
As shown in fig. 2, the above six strokes are respectively shown, namely: an intake stroke, a compression stroke, an intake expansion stroke, an expansion stroke, a power stroke, and an exhaust stroke.
When the multi-stroke cycle engine is operated, different stroke cycle modes can be adopted according to requirements, such as: four-stroke, six-stroke, eight-stroke, ten-stroke, etc. are employed, and in each stroke cycle mode, a combination of different stroke types may be employed as desired. Regardless of the stroke cycle pattern and combination of stroke types, the intake stroke begins as the first stroke and the exhaust stroke ends as the last stroke of the stroke cycle, and there is at least one power stroke in a stroke cycle.
As shown in connection with fig. 2, the first stroke is an intake stroke during which the intake valve or port is appropriately opened to draw fresh air or mixture (e.g., mixture including combustible gas, recirculated exhaust gas, etc.) into the combustion chamber formed by the cylinder bore, piston, and cylinder head. Namely: the first stroke forms the first intake of the stroke cycle.
On the second stroke immediately after the first stroke, the intake valve or the intake port is closed, the exhaust valve or the exhaust port is kept closed, the combustion chamber is kept closed, and the piston moves upward, the mixture in the combustion chamber is compressed, thus forming a second stroke, which is the first compression (i.e., compression stroke).
The third stroke, which is immediately after the second stroke, may be any one of a power stroke, an expansion stroke and a suction expansion stroke, thus forming a first power (i.e., power stroke), a first expansion (i.e., expansion stroke) or a first suction expansion (i.e., suction expansion stroke) in the stroke cycle.
The fourth stroke immediately following the third stroke is determined by the actual action of the third stroke, and there may be the following:
the third stroke is a power stroke and the fourth stroke may be an exhaust stroke or a compression stroke (i.e., a second compression). If the fourth stroke is an exhaust stroke, then the end of a conventional four-stroke cycle is considered. If the fourth stroke is a compression stroke (i.e., second compression), then a multi-stroke cycle is indicated in which the number of strokes (even) for the cycle is greater than 4.
Four-stroke, six-stroke, eight-stroke, ten-stroke cycle modes are described below:
the four-stroke cycle process is as follows:
intake stroke-compression stroke-power stroke-exhaust stroke.
The six-stroke cycle process is as follows:
a. air suction-compression 1-work 1-compression 2-work 2-exhaust;
b. suction-compression 1-work-compression 2-expansion-exhaust;
c. suction-compression 1-expansion-compression 2-work-exhaust;
d. suction-compression 1-suction expansion-compression 2-work-exhaust.
The eight-stroke cycle process is as follows:
a. air suction-compression 1-work 1-compression 2-work 2-compression 3-work 3-exhaust;
b. air suction-compression 1-work 1-compression 2-work 2-compression 3-expansion-exhaust;
c. air suction-compression 1-work 1-compression 2-expansion-compression 3-work 2-exhaust;
d. suction-compression 1-doing work 1-compression 2-suction expansion-compression 3-doing work 2-exhausting;
e. air suction, compression 1, expansion, compression 2, work application 1, compression 3, work application 2 and air exhaust;
f. suction-compression 1-suction expansion-compression 2-work 1-compression 3-work 2-exhaust;
g. suction-compression 1-suction expansion 1-compression 2-suction expansion 2-compression 3-work-exhaust;
h. suction-compression 1-suction expansion-compression 2-expansion-compression 3-work-exhaust;
i. suction-compression 1-expansion-compression 2-suction expansion-compression 3-work-exhaust;
j. air suction, compression 1, expansion 1, compression 2, expansion 2, compression 3, work application and air exhaust;
k. suction-compression 1-suction expansion-compression 2-work-compression 3-expansion-exhaust;
air suction-compression 1-expansion 1-compression 2-work-compression 3-expansion 2-exhaust;
m. suction-compression 1-work-compression 2-expansion 1-compression 3-expansion 2-exhaust.
The ten-stroke cycle process is:
a. air suction-compression 1-work 1-compression 2-work 2-compression 3-work 3-compression 4-work 4-exhaust;
b. air suction-compression 1-work 1-compression 2-work 2-compression 3-work 3-compression 4-expansion-exhaust;
c. air suction-compression 1-work 1-compression 2-expansion-compression 3-work 2-compression 4-work 3-exhaust;
d. suction-compression 1-work 1-compression 2-suction expansion-compression 3-work 2-compression 4-work 3-exhaust;
e. air suction, compression 1, expansion, compression 2, work doing 1, compression 3, work doing 2, compression 4, work doing 3 and exhaust;
f. suction-compression 1-suction expansion-compression 2-work 1-compression 3-work 2-compression 4-work 3-exhaust;
g. air suction-compression 1-expansion 1-compression 2-work 1-compression 3-work 2-compression 4-expansion 2-exhaust;
h. suction-compression 1-suction expansion-compression 2-work 1-compression 3-work 2-compression 4-expansion-exhaust;
i. air suction-compression 1-expansion 1-compression 2-work 1-compression 3-expansion 2-compression 4-work 2-exhaust;
j. suction-compression 1-suction expansion-compression 2-work 1-compression 3-expansion-compression 4-work 2-exhaust;
k. air suction-compression 1-expansion 1-compression 2-expansion 2-compression 3-work 1-compression 4-work 2-exhaust;
l, air suction-compression 1-air suction expansion-compression 2-expansion-compression 3-work 1-compression 4-work 2-exhaust;
m, air suction-compression 1-air suction expansion 1-compression 2-air suction expansion 2-compression 3-work 1-compression 4-work 2-exhaust;
n, air suction-compression 1-expansion-compression 2-air suction expansion-compression 3-work 1-compression 4-work 2-exhaust;
o, suction-compression 1-work 1-compression 2-expansion 1-compression 3-work 2-compression 4-expansion 2-exhaust;
p, suction-compression 1-work 1-compression 2-suction expansion-compression 3-work 2-compression 4-expansion-exhaust;
q. air suction-compression 1-work application 1-compression 2-expansion 1-compression 3-expansion 2-compression 4-work application 2-exhaust;
r, air suction-compression 1-work application 1-compression 2-expansion-compression 3-air suction expansion-compression 4-work application 2-exhaust;
s. air suction-compression 1-work application 1-compression 2-air suction expansion-compression 3-expansion-compression 4-work application 2-exhaust;
t, air suction-compression 1-work application 1-compression 2-work application 2-compression 3-expansion 1-compression 4-expansion 2-exhaust;
u, air suction-compression 1-work-compression 2-expansion 1-compression 3-expansion 2-compression 4-expansion 3-exhaust;
v. suction-compression 1-expansion 1-compression 2-work-compression 3-expansion 2-compression 4-expansion 3-exhaust;
suction-compression 1-suction expansion-compression 2-work-done-compression 3-expansion 1-compression 4-expansion 2-exhaust;
x, air suction-compression 1-expansion 1-compression 2-expansion 2-compression 3-work-compression 4-expansion 3-exhaust;
y. air suction-compression 1-air suction expansion-compression 2-expansion 1-compression 3-work-compression 4-expansion 2-exhaust;
z. air suction-compression 1-air suction expansion 1-compression 2-air suction expansion 2-compression 3-work-compression 4-expansion-exhaust;
aa, air suction-compression 1-expansion 1-compression 2-air suction expansion-compression 3-work-compression 4-expansion 2-exhaust;
ab. air suction-compression 1-expansion 1-compression 2-expansion 2-compression 3-expansion 3-compression 4-work-exhaust;
ac, inspiration-compression 1-expansion 1-compression 2-expansion 2-compression 3-inspiration expansion-compression 4-work-exhaust;
ad. air suction-compression 1-expansion 1-compression 2-air suction expansion-compression 3-expansion 2-compression 4-work-exhaust;
ae. air suction-compression 1-expansion-compression 2-air suction expansion 1-compression 3-air suction expansion 2-compression 4-work-done-exhaust;
af. air suction-compression 1-air suction expansion-compression 2-expansion 1-compression 3-expansion 2-compression 4-work-exhaust;
ag. air suction-compression 1-air suction expansion 1-compression 2-air suction expansion 2-compression 3-expansion-compression 4-work-done-exhaust;
ah. air suction-compression 1-air suction expansion 1-compression 2-expansion-compression 3-air suction expansion 2-compression 4-work-done-exhaust;
ai, air suction-compression 1-air suction expansion 1-compression 2-air suction expansion 2-compression 3-air suction expansion 3-compression 4-work-exhaust.
By analogy, more stroke working cycles can be realized, such as: twelve-stroke cycle mode, fourteen-stroke cycle mode, sixteen-stroke cycle mode, etc.
Having described the combination of the multi-stroke cycle modes of the multi-stroke cycle engine of the embodiment of the present invention and the stroke types in each of the stroke cycle modes, the control method of the multi-stroke cycle engine of the embodiment of the present invention is described in detail below.
As shown in fig. 1, a control method of a multi-stroke cycle engine according to an embodiment of the present invention includes the steps of:
s101: a driving mode selection signal and engine fault information are received.
The driver mode selection signal may be triggered by a mode selection button on the vehicle, such as: the vehicle is provided with a four-stroke cycle mode button and a free-stroke cycle mode button, when a user triggers the four-stroke cycle mode button, the engine can only work in the four-stroke cycle mode, and when the user triggers the free-stroke cycle mode button, the engine can work in the multi-stroke cycle mode. In addition, a fault message of the engine CAN be obtained through the CAN bus, and whether the engine has a fault or not is judged according to fault information in the fault message.
It will be appreciated that the manner how the driving mode selection signal is received is not limited to this, for example: or embedded into the independent judgment and control layer of each driving mode, so as to determine whether the free stroke cycle mode is selected.
S102: and judging whether the multi-stroke cycle mode entering condition is met or not according to the driving mode selection signal and the fault information. Namely: if the user activates the free-stroke cycle mode button, the engine may operate in the multi-stroke cycle mode. Further, when the engine is not malfunctioning, it is determined that the multi-stroke cycle mode entry condition is satisfied.
S103: if so (i.e., the multi-stroke cycle mode entry condition is satisfied), matching the corresponding multi-stroke cycle mode and stroke combination according to the operating conditions of the engine and the engine operating state information.
The engine operating state information includes, but is not limited to, engine water temperature (also referred to as engine temperature), engine speed, engine load signal, engine timing signal/top dead center signal, in-cylinder pressure signal, knock sensor signal, intake air flow, oxygen sensor signal. The operating conditions of the engine include, for example, a start-up condition, a warm-up condition, and a normal operating condition.
The stroke cycle, which stroke cycle mode is used and which stroke type in the stroke cycle modes is used, can be selected according to the actual operation condition of the transmitter.
The engine can be operated in a multi-stroke cycle mode besides a conventional four-stroke cycle mode under the working conditions of starting, warming up, steady state, dynamic state and the like.
For example, when the engine is started, the combination of 'a, air suction-compression 1-acting 1-compression 2-acting 2-compression 3-acting 3-exhaust' strokes in an eight-stroke cycle mode can be adopted, continuous acting is performed by using three continuous compression injection combustion processes, the starting success rate can be improved, the discharge of hot exhaust gas can be delayed, the temperature of a combustion chamber can be increased, the temperature rise of the cylinder wall can be accelerated, and the emission of pollutants such as Hydrocarbon (HC) and Particulate Matters (PM) can be reduced.
Of course, a combination of "d. suction-compression 1-power 1-compression 2-suction expansion-compression 3-power 2-exhaust" strokes in an eight-stroke cycle mode may also be used. Namely: after the compression 2 which is immediately after the first combustion does work, introducing an air suction expansion stroke, properly opening an air inlet valve at a proper time when a piston runs downwards to be close to a bottom dead center, and introducing a certain amount of fresh air into the cylinder from an air inlet channel, so that the oxygen concentration of mixed air in the cylinder can be improved, and the assistance is provided for the combustion process which is immediately after the compression 3 and does work 2, thereby achieving the purposes of high-efficiency starting and low emission.
Specifically, taking the operation condition of the engine as a cold start condition as an example: in the cold starting process, a multi-stroke multi-combustion circulation mode or a multi-stroke multi-compression single-combustion circulation mode can be adopted to preheat mixed gas in a cylinder, reduce exhaust heat energy loss, improve heat efficiency, reduce THC (TOTAL hydrocarbon contained in exhausted gas), carbon monoxide (CO) and Particulate Matter (PM) emission and achieve the effect of accelerating the temperature rise of an engine.
As shown in fig. 3, the vehicle is powered on, and the driving mode selection signal and the failure information are first detected to perform the multi-stroke cycle mode selection or the safety mode (i.e., the conventional four-stroke cycle mode). When satisfied, the conditions are entered according to the multi-stroke cycle mode, and then the execution can be carried out according to the matched multi-stroke cycle mode. Otherwise, normal four-stroke mode execution will be assumed or no start will be initiated.
After the vehicle is electrified, detecting the water temperature of the engine, and if the water temperature of the engine is lower than a set temperature threshold value (Tm < T)cstulimTm represents the engine water temperature TcstulimIs a set temperature threshold representing an upper cold start temperature limit, wherein TcstulimCan be selected between minus 10 ℃ and 20 ℃), the cold start working condition is judged; otherwise, the hot start condition is adopted.
And when the working condition is a cold starting working condition, activating corresponding timing judgment and cylinder sequence relation calculation strategies. And finishing cylinder judgment and timing synchronism check and continuously monitoring within the time from the sending of the starting instruction to the time before the starter and the like drive the crankshaft to reach the required starting rotating speed.
If the monitoring is correct, the timing determination and the synchronism check are correct, and the crankshaft reaches and exceeds the starting speed (starting speed N)sstBetween 100rpm and 350 rpm), the intake/exhaust timing and lift, fuel injection amount and timing, and ignition timing will be performed according to a predetermined multi-stroke cycle pattern and start control logicAnd the like, so that the engine obtains a reasonable overshoot speed.
After the engine obtains enough uprush rotating speed, the rotating speed of the engine is rapidly stabilized at a certain set target speed and keeps stable operation for a certain number of cycles, and then the end of starting, namely the end of the cold starting process, is judged. And then the heating, economical running, rapid acceleration or stopping working conditions can be switched to in time according to the operation requirements of a driver and the like.
Further, as shown in fig. 4, taking the warm-up condition as an example, after the driver completes the cold start operation, if no other operation is performed, the warm-up condition is entered immediately after the cold start condition.
Specifically, before the cold start is completed, the warm-up condition is entered, and when the condition of the multi-stroke mode is confirmed to be met, the corresponding multi-stroke cycle mode is matched. Firstly, activating corresponding timing judgment and cylinder sequence relation calculation strategies, completing cylinder judgment and timing synchronism check, and continuously monitoring.
If the cylinder judgment and timing synchronism check are wrong, executing a conventional four-stroke cycle mode, otherwise detecting the water temperature of the engine, and if the water temperature of the engine is lower than a set warming temperature threshold value (namely Tm < T)wmulimTm is the water temperature of the engine; t iswmulimFor a set warm-up temperature threshold, TwmulimOptionally between 20 c and 60 c), a warm-up condition is determined. And controlling the engine to run according to the matched multi-stroke cycle mode. And after the water temperature of the engine is higher than a set warming temperature threshold value, the engine enters a normal operation working condition.
Cylinder pressure and/or shock signals are further monitored. If cylinder pressure or shock signals are monitored that do not exceed a threshold, the multi-stroke cycle mode is maintained. If the cylinder pressure or the vibration signal is monitored to exceed the threshold value, or the abnormal combustion causes damage to the engine body structure, protective measures are taken, the multi-stroke cycle mode is exited, and the operation is switched to the conventional four-stroke cycle mode.
In addition, the multi-stroke cycle mode may also be employed when the engine is in a normal operating temperature state (i.e., normal operating conditions). In this state, the engine is required to be efficient, energy-saving and environment-friendly, so the adopted stroke combination can be different from the stroke combination corresponding to the starting and warming working conditions. Under this condition, a combination of "d. intake-compression 1-intake expansion-compression 2-power-exhaust" strokes in a six-stroke cycle mode may be employed, with premixing of the first fuel with a first amount of air during intake-compression 1, introduction of a second amount of air during the subsequent intake expansion stroke, and optionally injection of a second fuel before compression 2 is over, followed by completion of spark power and exhaust, as desired. Namely: by delaying the work application and the exhaust, and introducing the air suction expansion-compression 2 after the compression 1, the air-fuel mixing period is prolonged, the uniformity of the mixed gas is better, the combustion initial temperature is favorably reduced, the combustion duration is shortened, the combustion efficiency is improved, and the aims of high efficiency, oil saving, low emission, environmental protection and the like are fulfilled.
Of course, it is also possible to use the "f.suction-compression 1-suction expansion-compression 2-work 1-compression 3-work 2-exhaust" stroke combination in an eight-stroke cycle mode. Premixing a first fuel with a first amount of air during the suction-compression 1; in the subsequent suction-expansion stroke, a second air quantity is introduced, and a second fuel injection can be selected before the end of the compression 2 as required, and the ignition is carried out for the first combustion, namely work 1 is done; after that, the compression 3 operation is performed, and a third fuel injection may be optionally performed before the compression 3 is finished; then the second combustion, work 2 and exhaust, is completed. The stroke combination of two or more times of work in the multi-stroke circulation mode is selected, so that the over-high explosion pressure of a single work stroke can be avoided, and the work done by combustion each time can be in a high-efficiency area by doing work for many times, thereby achieving the purposes of energy conservation, emission reduction and low combustion noise.
Specifically, when the engine is in a normal operating temperature state (i.e., a normal operating condition), there is more chance that the engine will operate at a medium-low speed and a medium-low load condition. Therefore, in a proper rotating speed and load interval, a multi-stroke circulation mode can be adopted to improve the fuel economy and improve the emission of part of pollutants.
First, a multi-stroke cycle mode determination is performed. And when the multi-stroke cycle mode can be entered, activating corresponding timing judgment and cylinder sequence relation calculation strategies, completing cylinder judgment and timing synchronism check, and continuously monitoring.
If the cylinder determination and timing synchronicity check are in error, the conventional four-stroke cycle mode is executed, otherwise, the operation is performed according to the matched multi-stroke cycle mode. And meanwhile, judging whether the cylinder pressure and/or the knock sensor signal exceeds the limit. If there is no overrun, the multi-stroke cycle mode continues.
The conventional four-stroke cycle mode is defined as a safe operating mode. The safe operating mode is executed in the following cases:
1) in a non-failure condition, if the engine operating mode is selectable and the driver has subjectively selected the safe operating mode, then the engine is operated in the conventional four-stroke cycle mode.
2) The driver is not in charge of selecting the four-stroke cycle mode but the engine is out of order, or operates in the conventional four-stroke cycle mode under heavy load conditions.
3) When the engine is in operation, cylinder pressure and knock are exceeded, causing a switch to conventional four-stroke cycle mode operation.
S104: the engine is controlled based on the determined multi-stroke cycle mode and stroke combination.
Further, in step S102, when it is determined that the multi-stroke cycle mode entry condition is not satisfied, the control method of the multi-stroke cycle engine of the embodiment of the present invention may control the engine according to a conventional four-stroke cycle mode, that is: a four-stroke cycle mode, wherein the four-stroke cycle process comprises the following steps: the method comprises the following steps of air suction stroke-compression stroke-power stroke-exhaust stroke, which is called air suction-compression-power-exhaust for short.
According to the control method of the multi-stroke cycle engine, the fuel economy of the engine under multiple operating conditions can be effectively improved, and the emission of tail gas pollutants is reduced.
Fig. 5 is a block diagram of a control system for a multi-stroke cycle engine according to an embodiment of the present invention. As shown in fig. 5, a control system 500 for a multi-stroke cycle engine according to one embodiment of the present invention includes: a receiving module 510, a determining module 520, a multi-stroke cycle mode determination module 530, and a control module 540.
The receiving module 510 is configured to receive a driving mode selection signal and engine fault information. The judging module 520 is configured to judge whether the multi-stroke cycle mode entering condition is satisfied according to the driving mode selection signal and the fault information. The multi-stroke cycle mode determination module 530 is configured to match the corresponding multi-stroke cycle mode and stroke combination according to the operating condition of the engine and the engine operating state information when the determination module 520 determines that the multi-stroke cycle mode entry condition is satisfied. The control module 540 is configured to control the engine based on the determined multi-stroke cycle mode and stroke combination.
Further, the multi-stroke cycle engine further comprises an intake expansion stroke and an expansion stroke, wherein the expansion stroke is a process in which an intake valve and an exhaust valve are closed and a piston descends from a top dead center; the suction expansion stroke refers to a process of opening an intake valve at a proper time to suck a predetermined amount of air or air-fuel mixture in the process of the expansion of the piston descending from the top dead center.
In one embodiment of the invention, the operating conditions of the engine include a start condition, a warm-up condition, and a normal operating condition.
The control system 500 of the multi-stroke cycle engine according to the embodiment of the present invention further includes: and when it is judged that the multi-stroke cycle mode entry condition is not satisfied, controlling the engine according to a conventional four-stroke cycle mode.
According to the control system of the multi-stroke cycle engine, the fuel economy of the engine under multiple operating conditions can be effectively improved, and the emission of tail gas pollutants is reduced.
It should be noted that the specific implementation manner of the control system of the multi-stroke cycle engine according to the embodiment of the present invention is similar to the specific implementation manner of the control method of the multi-stroke cycle engine according to the embodiment of the present invention, and please refer to the description of the method part specifically, and details are not repeated here in order to reduce redundancy.
Further, an embodiment of the invention discloses a vehicle provided with the control system of the multi-stroke cycle engine as described in any one of the above embodiments. The vehicle can effectively improve the fuel economy of the engine under a plurality of operating conditions and reduce the emission of tail gas pollutants.
In addition, other configurations and functions of the vehicle according to the embodiment of the present invention are known to those skilled in the art, and are not described herein in detail in order to reduce redundancy.
The embodiment of the invention discloses a mode switching method of a multi-stroke cycle engine. As shown in fig. 6, a mode switching method of a multi-stroke cycle engine according to an embodiment of the present invention includes the steps of:
s601: when the engine is in the current multi-stroke cycle mode, it is determined whether the in-cylinder pressure exceeds a pressure limit corresponding to the current multi-stroke cycle mode and whether the knock sensor signal exceeds a knock limit corresponding to the current multi-stroke cycle mode.
S602: if the in-cylinder pressure does not exceed the pressure limit corresponding to the current multi-stroke cycle mode and the knock sensor signal does not exceed the knock limit corresponding to the current multi-stroke cycle mode, a further determination is made as to whether the engine speed and engine load exceed the speed and load intervals corresponding to the current multi-stroke cycle mode.
S603: and if the engine speed and/or the engine load exceed the speed interval and the load interval corresponding to the current multi-stroke cycle mode, switching the current multi-stroke cycle mode to the target multi-stroke cycle mode.
Further, the mode switching method of the multi-stroke cycle engine according to the embodiment of the present invention further includes: switching the current multi-stroke cycle mode to a conventional four-stroke cycle mode if the in-cylinder pressure exceeds a pressure limit corresponding to the current multi-stroke cycle mode and/or the knock sensor signal exceeds a knock limit corresponding to the current multi-stroke cycle mode.
Wherein switching the current multi-stroke cycle mode to the target multi-stroke cycle mode comprises: a cylinder deactivation transition switching method and a successive continuous switching method. Further, when the engine speed in the current multi-stroke cycle mode is lower than the engine speed in the target multi-stroke cycle mode, the switching from the current multi-stroke cycle mode to the target multi-stroke cycle mode is performed by adopting a successive continuous switching method.
Specifically, as shown in connection with fig. 7, transition switching between the multi-stroke cycle modes is a key link for flexible application of the multi-stroke cycle modes. Take the example of switching from the multi-stroke cycle mode a to the multi-stroke cycle mode b, wherein the number of strokes of the multi-stroke cycle mode a is NaThe number of strokes of the multi-stroke cycle pattern b is Nb。
When N is presenta≠NbThen, the handover procedure is as follows:
1) when the engine runs in a multi-stroke cycle mode a, two-path cycle timing sequence operation and simulation coordination check are simultaneously carried out, and the operation is kept accurate and free of errors.
2) And judging whether to switch according to the feedback of the engine speed, the engine load, the in-cylinder pressure, the knock sensor signal and the accelerator pedal position sensor signal.
3) And when the in-cylinder pressure or the knock signal of the engine is determined not to exceed the calibration limit value, the operating condition (rotating speed and load) of the engine exceeds the calibration interval corresponding to the multi-stroke cycle mode a, and the multi-cycle timing sequence operation and the simulation in the step 1 are coordinated without errors, the switching to the multi-stroke cycle mode b is allowed.
4) The switching manner mentioned in the above 3 includes a cylinder deactivation transition switching method (hereinafter referred to as a first switching method) and a successive consecutive switching method (hereinafter referred to as a second switching method).
5) And when the switching is allowed in step 3, starting with the detected first reference cylinder, executing the oil-cut operation based on the multi-stroke cycle mode b, and gradually switching the oil-cut operation of the multi-stroke cycle mode b to the other cylinders according to the working sequence of the multi-stroke cycle mode b until the last cylinder finishes the next reference cylinder after the last multi-stroke cycle mode a and starts to recover oil supply, executing the multi-stroke cycle mode b, and further finishing the switching process from the multi-stroke cycle mode a to the multi-stroke cycle mode b. This is the first switching method.
6) In Na≤NbIn this case, the switching of the multi-stroke cycle mode may be completed by the second switching method. For example, when switching is allowed in 3, the running operation of the multi-stroke cycle pattern b will be executed starting with the detected first reference cylinder; and the other cylinders are sequentially switched to the multi-stroke circulation mode b for operation according to the working sequence, so that the switching from the multi-stroke circulation mode a to the multi-stroke circulation mode b is completed.
7) As described in the above 1, if the multi-path sequence calculation and coordination judgment are in error, the engine is maintained at NaThe number of strokes continues to run the operation of the multi-stroke cycle mode a.
8) If the operating conditions (rotation speed and load) of the engine do not exceed the calibration interval corresponding to the multi-stroke cycle mode a in the above step 3, the engine is maintained at the N valueaThe number of strokes continues to run the multi-stroke cycle pattern a.
9) As the cylinder pressure or the detonation signal exceeds the calibration limit value in the step 3, protective measures, namely oil cut-off, torque limitation, switching to a safe operation mode, protective shutdown and the like are taken according to different danger degrees to protect the engine and avoid the engine from being damaged.
10) When N is presenta＝NbThe mode switching process with different stroke combinations is as follows: and when the engine operating condition exceeds the calibration interval corresponding to the multi-stroke cycle mode a and the cylinder pressure or the knock signal does not exceed the calibration limit value, the switching condition is met. In this case, the handover procedure can be completed by both the first handover method and the second handover method described above.
According to the mode switching method of the multi-stroke cycle engine, the multi-stroke cycle mode can be switched simply and conveniently to meet the requirements of the engine on different operating conditions, so that the fuel economy of the engine in multiple operating conditions can be effectively improved, and the emission of tail gas pollutants is reduced.
FIG. 8 is a block diagram of a mode switching system for a multi-stroke cycle engine according to one embodiment of the present invention. As shown in fig. 8, a mode switching system 800 of a multi-stroke cycle engine according to an embodiment of the present invention includes: a first judging module 810, a second judging module 820 and a switching module 830.
The first determining module 810 is configured to determine whether an in-cylinder pressure exceeds a pressure limit corresponding to a current multi-stroke cycle mode and whether the knock sensor signal exceeds a knock limit corresponding to the current multi-stroke cycle mode when the engine is in the current multi-stroke cycle mode. The second determination module 820 is configured to further determine whether an engine speed and an engine load exceed a speed and load interval corresponding to the current multi-stroke cycle mode when the in-cylinder pressure does not exceed a pressure limit corresponding to the current multi-stroke cycle mode and the knock sensor signal does not exceed a knock limit corresponding to the current multi-stroke cycle mode. The switching module 830 is configured to switch the current multi-stroke cycle mode to a target multi-stroke cycle mode when the engine speed and/or the engine load exceeds a speed interval and a load interval corresponding to the current multi-stroke cycle mode.
Further, the switching module 830 is further configured to: switching the current multi-stroke cycle mode to a conventional four-stroke cycle mode if the in-cylinder pressure exceeds a pressure limit corresponding to the current multi-stroke cycle mode and/or the knock sensor signal exceeds a knock limit corresponding to the current multi-stroke cycle mode.
In one embodiment of the present invention, switching the current multi-stroke cycle mode to the target multi-stroke cycle mode includes: a cylinder deactivation transition switching method and a successive continuous switching method. Further, when the engine speed in the current multi-stroke cycle mode is lower than the engine speed in the target multi-stroke cycle mode, the switching module performs switching from the current multi-stroke cycle mode to the target multi-stroke cycle mode by using the successive continuous switching method.
According to the mode switching system of the multi-stroke cycle engine, the multi-stroke cycle mode can be switched simply and conveniently to meet the requirements of the engine on different operating conditions, so that the fuel economy of the engine in multiple operating conditions can be effectively improved, and the emission of tail gas pollutants is reduced.
It should be noted that the specific implementation manner of the mode switching system of the multi-stroke cycle engine in the embodiment of the present invention is similar to the specific implementation manner of the mode switching method of the multi-stroke cycle engine in the embodiment of the present invention, and please refer to the description of the method part specifically, and details are not repeated here in order to reduce redundancy.
Further, an embodiment of the invention discloses a vehicle provided with a mode switching system of a multi-stroke cycle engine as described in any one of the above embodiments. The vehicle can simply and conveniently switch the multi-stroke circulation mode to adapt to the requirements of different operation conditions of the engine, so that the fuel economy of the engine in a plurality of operation conditions can be effectively improved, and the emission of tail gas pollutants is reduced.
In addition, other configurations and functions of the vehicle according to the embodiment of the present invention are known to those skilled in the art, and are not described herein in detail in order to reduce redundancy.
Fig. 9 is a flowchart of a control method of a multi-stroke cycle gasoline engine according to one embodiment of the present invention. As shown in fig. 9, the control method of the multi-stroke cycle gasoline engine according to one embodiment of the present invention includes the steps of:
s901: the type of the multi-stroke cycle gasoline engine is determined.
S902: if the multi-stroke cycle gasoline engine is a multi-stroke cycle direct injection gasoline engine, gasoline fuel is supplied to the combustion chamber during the end of the intake stroke and/or the compression stroke to the front of the power stroke in the current multi-stroke cycle mode.
S903: and determining the ignition time according to the compression end temperature, the average air-fuel ratio of the mixture, the gasoline fuel injection quantity near the compression top dead center and the fuel injection timing, and igniting at the ignition time.
S904: if the multi-stroke cycle gasoline engine is a multi-stroke cycle air passage injection gasoline engine, the air passage is supplied with gasoline fuel on the intake stroke and/or the exhaust stroke in the current multi-stroke cycle mode.
S905: the ignition timing is determined during the period from the end of the compression stroke to the front of the power stroke, and ignition is performed at the ignition timing.
Wherein, the period from the end of the compression stroke to the front of the power stroke refers to the period from 50 ℃ A before the compression top dead center to 30 ℃ A after the compression top dead center, and the ignition timing is positioned between 50 ℃ A before the compression top dead center and 30 ℃ A after the compression top dead center.
The control method of the multi-stroke cycle gasoline engine of the embodiment of the invention further comprises the following steps: when the multi-stroke cycle gasoline engine is a multi-stroke cycle direct injection gasoline engine, if the current multi-stroke cycle mode includes an expansion stroke and/or an intake expansion stroke, supplying gasoline fuel to the combustion chamber in the expansion stroke and/or the intake expansion stroke; when the multi-stroke cycle gasoline engine is a multi-stroke cycle air passage injection gasoline engine, if the current multi-stroke cycle mode includes an intake expansion stroke, gasoline fuel is supplied to the air passage in a later stage of the intake expansion stroke. Wherein, the rear section of the suction expansion stroke refers to 120 ℃ A to 0 ℃ A before the compression top dead center.
Specifically, gasoline engine combustion is premixed combustion, and the fuel combustion efficiency is determined by the uniformity of the premixing. The premixing effect is one of the key targets of the design and development of a combustion system and the control of the combustion process, and therefore, the fuel supply and ignition control are particularly important.
For the fuel supply:
in the case of a multi-stroke cycle direct injection gasoline engine, fuel may be supplied to the combustion chamber during the intake stroke, the expansion stroke, the intake-expansion stroke, and from the end of the compression stroke to the beginning of the power stroke (i.e., between 50 ℃ A before compression top dead center and 30 ℃ A after compression top dead center).
The longest premixing time can be obtained by supplying fuel in the suction stroke, thereby being beneficial to mixing of large-load and large-flow working media and realizing rapid combustion.
In the expansion or air-suction expansion stroke, a small amount of fuel is supplied, so that the fuel concentration of the homogeneous mixed gas is properly increased (the air-fuel ratio of the homogeneous mixed gas is reduced), and the combustion supporting effect is realized. And the temperature of the mixed gas can be restrained from rising suddenly after compression is finished by utilizing the evaporation heat absorption effect of the liquid fuel.
A small amount of fuel is supplied from the end of the compression stroke to the front of the power stroke, the fuel evaporates and absorbs heat, the temperature of the compression end point is reduced, the detonation is inhibited, and the relatively rich mixed gas is formed around the spark plug, so that the stagnation period is shortened, and the rapid combustion is organized.
For the fuel supply:
if the engine is a multi-stroke cycle air passage injection gasoline engine, fuel can be supplied into the air passage during the intake stroke, the second half of the intake expansion stroke (namely, 120 ℃ A to 0 ℃ A before the compression top dead center), and the exhaust stroke.
The fuel is supplied in the exhaust stroke and the suction stroke, so that longer premixing time can be obtained, the mixing of a heavy-load working medium is facilitated, the combustion is more sufficient, and the combustion efficiency is improved.
And a proper amount of fuel is supplied in the air suction expansion stroke, a certain amount of mixed gas is conveyed to the combustion chamber, the concentration of effective working media in the combustion chamber is improved, and the uniformity of the mixed gas in the cylinder is improved so as to assist the subsequent combustion working process.
For ignition control:
if the engine is a spark ignition air passage injection gasoline engine with a multi-stroke cycle or a direct injection gasoline engine, the ignition control is calibrated according to the combustion event matching of the power stroke.
The ignition timing is at a certain moment from the end of the compression stroke to the front of the expansion stroke (namely, the spark ignition timing is between 50 ℃ A before the compression top dead center and 30 ℃ A after the compression top dead center), so that the combustion center is reasonable, and the combustion process is stable, safe and efficient.
If a Homogeneous Charge Compression Ignition direct injection gasoline engine with a multi-stroke cycle (namely, an HCCI direct injection gasoline engine, HCCI is called Homogeneous Charge Compression Ignition), the safety, stability and high efficiency of the HCCI combustion process should be ensured through cylinder pressure monitoring means, and high-precision intake air calculation and fuel supply. The ignition timing of the HCCI combustion mode is determined by the compression end temperature, the mixture average air-fuel ratio, and the fuel injection amount and timing in the vicinity of compression top dead center in combination.
According to the control method of the multi-stroke cycle gasoline engine, the appropriate oil injection time and ignition time can be determined according to different multi-stroke cycle modes, so that the fuel economy of the engine under multiple operating conditions can be effectively improved, and the emission of tail gas pollutants is reduced.
Fig. 10 is a block diagram of a control system of a multi-cycle gasoline engine according to an embodiment of the present invention. As shown in fig. 10, a control system 1100 for a multi-cycle gasoline engine according to one embodiment of the present invention includes: an injection module 1010 and an ignition module 1020.
The fuel injection module 1010 is used for supplying gasoline fuel to a combustion chamber in the end of an intake stroke and/or a compression stroke to the front of a power stroke in the current multi-stroke cycle mode when the multi-stroke cycle gasoline engine is a multi-stroke cycle direct injection gasoline engine, and supplying gasoline fuel to an air passage in the intake stroke and/or an exhaust stroke in the current multi-stroke cycle mode when the multi-stroke cycle gasoline engine is a multi-stroke cycle air passage injection gasoline engine. The ignition module 1020 is configured to determine an ignition timing according to a compression end temperature, an average air-fuel ratio of a mixture, a gasoline fuel injection amount near a compression top dead center, and an injection timing and to ignite at the ignition timing when the multi-stroke cycle gasoline engine is a multi-stroke cycle direct injection gasoline engine, and determine the ignition timing during a period from an end of a compression stroke to a front of a power stroke and to ignite at the ignition timing when the multi-stroke cycle gasoline engine is a multi-stroke cycle air passage injection gasoline engine.
Further, the period from the end of the compression stroke to the front of the power stroke is from 50 ℃ A before the compression top dead center to 30 ℃ A after the compression top dead center, and the ignition timing is from 50 ℃ A before the compression top dead center to 30 ℃ A after the compression top dead center.
In one embodiment of the present invention, the fuel injection module 1100 is further configured to: when the multi-stroke cycle gasoline engine is a multi-stroke cycle direct injection gasoline engine, if the current multi-stroke cycle mode comprises an expansion stroke and/or an air suction expansion stroke, supplying gasoline fuel to a combustion chamber in the expansion stroke and/or the air suction expansion stroke; when the multi-stroke cycle gasoline engine is a multi-stroke cycle air passage injection gasoline engine, if the current multi-stroke cycle mode comprises an air suction expansion stroke, gasoline fuel is supplied to the air passage at the later section of the air suction expansion stroke.
According to the control system of the multi-stroke cycle gasoline engine, the appropriate oil injection time and ignition time can be determined according to different multi-stroke cycle modes, so that the fuel economy of the engine under multiple operating conditions can be effectively improved, and the emission of tail gas pollutants is reduced.
It should be noted that the specific implementation manner of the control system of the multi-stroke cycle gasoline engine according to the embodiment of the present invention is similar to the specific implementation manner of the control method of the multi-stroke cycle gasoline engine according to the embodiment of the present invention, and please refer to the description of the method part specifically, and details are not repeated here in order to reduce redundancy.
Further, an embodiment of the invention discloses a vehicle provided with the control system of the multi-stroke cycle gasoline engine as described in any one of the above embodiments. This vehicle can confirm suitable oil spout moment and ignition moment according to the difference of many stroke cycle modes to can effectively promote the fuel economy of engine in a plurality of operating condition, and reduce the emission of tail gas pollutant.
In addition, other configurations and functions of the vehicle according to the embodiment of the present invention are known to those skilled in the art, and are not described herein in detail in order to reduce redundancy.
FIG. 11 is a flow chart of a method of controlling a multi-stroke cycle dual fuel engine according to one embodiment of the present invention. As shown in fig. 11, the control method of the multi-stroke cycle dual fuel engine according to one embodiment of the present invention includes the steps of:
s1101: gasoline fuel is supplied to the air passage when the cylinder is in the intake stroke and/or the exhaust stroke.
S1102: when the cylinder is located at the end of the adjacent compression stroke to the front of the expansion stroke, diesel fuel is supplied into the cylinder.
S1103: the ignition is carried out in a compression ignition mode or a spark ignition mode or a compression ignition mode is selected according to the proportion of the gasoline fuel and the diesel fuel in the operating condition of the multi-stroke cycle dual-fuel engine.
Wherein, the adjacent compression stroke end to the working stroke front section means between 60 ℃ A before the compression top dead center and 30 ℃ A after the compression top dead center.
The control method of the multi-stroke cycle dual-fuel engine of the embodiment of the invention also comprises the following steps: if the current multi-stroke cycle mode includes the intake expansion stroke, gasoline fuel is supplied to the air passage at a later stage of the intake expansion stroke. Further, the later part of the suction expansion stroke refers to 120 ℃ A to 0 ℃ A before the compression top dead center.
Specifically, the fuel supply mode of the multi-stroke cycle dual-fuel engine comprises air passage injection gasoline and in-cylinder direct injection diesel, and the ignition mode can select a spark ignition mode or a compression ignition mode according to the specific gravity relation (namely the supply ratio of the gasoline to the diesel) of fuel supply under different working conditions of the engine.
For the fuel supply:
gasoline fuel may be supplied to the intake port during the intake stroke, the latter half of the intake expansion stroke (i.e., between 120 and 0 c a before compression top dead center), and the exhaust stroke, as needed.
Diesel fuel may be delivered into the cylinder during the end of the adjacent compression stroke to the early part of the power stroke (i.e., greater than or equal to one fuel injection may be performed between 60 degrees celsius a before compression top dead center to 30 degrees celsius after compression top dead center, including the pre-injection) to support a compression combustion event for the subsequent power stroke. Moreover, the supply of the gasoline fuel and the diesel fuel does not interfere with each other, and the matching can be flexibly performed in one multi-stroke cycle.
For ignition control:
the engine can adopt a compression ignition mode to ignite under any working condition, and in addition, a spark ignition or compression ignition mode can be selected according to the specific gravity relation of fuel supply under different working conditions of the engine.
Wherein, the fuel supply calibration which is more than or equal to one time is completed between 60 ℃ A before the compression top dead center and 30 ℃ A after the compression top dead center, thereby ensuring that the combustion gravity center of the compression spontaneous combustion process is reasonable, and the combustion process is stable, safe and efficient.
Under the working conditions of cold start and minimum load, a spark ignition type gasoline combustion mode can be adopted to achieve the purpose of quickly starting or accelerating the temperature rise of the combustion chamber.
According to the control method of the multi-stroke cycle dual-fuel engine, the appropriate gasoline injection time, diesel injection times and ignition time can be determined according to different multi-stroke cycle modes, so that the fuel economy of the engine in multiple operating conditions can be effectively improved, and the emission of tail gas pollutants is reduced.
FIG. 12 is a block diagram of a control system for a multi-cycle dual fuel engine, in accordance with one embodiment of the present invention. As shown in fig. 12, a control system 1200 for a multi-cycle dual fuel engine according to one embodiment of the present invention includes: a first injection module 1210 and a first ignition module 1220.
The first fuel injection module 1210 is used for supplying gasoline fuel to an air passage when a cylinder is in an intake stroke and/or an exhaust stroke, and supplying diesel fuel to the cylinder when the cylinder is in the end of an adjacent compression stroke to the front of a power stroke. The first ignition module 1220 is configured to ignite via compression ignition or to select a spark ignition or compression ignition based on a ratio of gasoline fuel to diesel fuel in an operating condition of the multi-stroke cycle dual fuel engine.
Wherein, the adjacent compression stroke end to the working stroke front section means between 60 ℃ A before the compression top dead center and 30 ℃ A after the compression top dead center.
In one embodiment of the present invention, the first fuel injection module 1210 is further configured to supply gasoline fuel to the air path during a later portion of the intake-expansion stroke when the current multi-stroke cycle mode includes the intake-expansion stroke.
According to the control system of the multi-stroke cycle dual-fuel engine, the appropriate gasoline injection time, diesel injection times and ignition time can be determined according to different multi-stroke cycle modes, so that the fuel economy of the engine under multiple operating conditions can be effectively improved, and the emission of tail gas pollutants is reduced.
It should be noted that the specific implementation manner of the control system of the multi-cycle dual-fuel engine in the embodiment of the present invention is similar to the specific implementation manner of the control method of the multi-cycle dual-fuel engine in the embodiment of the present invention, and please refer to the description of the method part specifically, and details are not repeated here in order to reduce redundancy.
Further, the embodiment of the invention discloses a vehicle which is provided with the control system of the multi-stroke cycle dual-fuel engine according to any one of the embodiments. This vehicle can confirm suitable petrol oil spout moment, diesel oil spout number of times and ignition moment according to the difference of many stroke cycle mode to can effectively promote the fuel economy of engine in a plurality of operating condition, and reduce the emission of tail gas pollutant.
In addition, other configurations and functions of the vehicle according to the embodiment of the present invention are known to those skilled in the art, and are not described herein in detail in order to reduce redundancy.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims (8)

1. A control method of a multi-stroke cycle engine, characterized in that the multi-stroke cycle engine includes at least an intake stroke, a compression stroke, a power stroke and an exhaust stroke, the number of strokes of the multi-stroke cycle engine is N, the N is an even number greater than four, a first stroke in the multi-stroke cycle mode is an intake stroke, a second stroke is a compression stroke, an N-th stroke is an exhaust stroke, and a third stroke to a (N-1) th stroke are obtained by combining the compression stroke and the power stroke, the control method comprising the steps of:
receiving a driving mode selection signal and fault information of an engine;
judging whether a multi-stroke cycle mode entering condition is met or not according to the driving mode selection signal and the fault information;
if yes, matching the corresponding multi-stroke cycle mode and stroke combination according to the operation working condition of the engine and the engine operation state information;
controlling the engine according to the determined multi-stroke cycle mode and the stroke combination, wherein the multi-stroke cycle engine further comprises an intake expansion stroke and an expansion stroke, wherein,
the expansion stroke is a process in which an intake valve and an exhaust valve are closed and a piston descends from a top dead center;
the suction expansion stroke refers to the process of opening an intake valve at proper time to suck a preset amount of air or mixture in the process of descending expansion of the piston from the top dead center,
the third stroke to the (N-1) th stroke are combined from the compression stroke, the power stroke, the suction-expansion stroke, and the expansion stroke, wherein,
a subsequent stroke immediately after the previous stroke is a compression stroke if the previous stroke among the third to (N-1) th strokes is a power stroke, an expansion stroke or a suction-expansion stroke;
a subsequent stroke immediately after the compression stroke is one of a power stroke, an expansion stroke, and a suction-expansion stroke if a previous stroke among the third to (N-1) th strokes is a compression stroke;
wherein the (N-1) th stroke is a power stroke or an expansion stroke.
2. The method of claim 1, wherein the operating conditions of the engine include a start condition, a warm-up condition, and a normal operating condition.
3. The control method of the multi-stroke cycle engine according to claim 1, characterized by further comprising:
and when it is judged that the multi-stroke cycle mode entry condition is not satisfied, controlling the engine according to a conventional four-stroke cycle mode.
4. The control method of the multi-stroke cycle engine as recited in claim 1 wherein the engine operating condition information includes engine water temperature, engine speed, engine load signal, engine timing signal/top dead center signal, in-cylinder pressure signal, knock sensor signal, intake air flow rate, oxygen sensor signal.
5. A control system of a multi-stroke cycle engine, wherein the multi-stroke cycle engine includes at least an intake stroke, a compression stroke, a power stroke, and an exhaust stroke, the number of strokes of the multi-stroke cycle engine is N, the N being an even number greater than four, a first stroke in the multi-stroke cycle mode is an intake stroke, a second stroke is a compression stroke, an N-th stroke is an exhaust stroke, and a third stroke to a (N-1) th stroke are obtained by combining the compression stroke and the power stroke, the control system comprising:
the receiving module is used for receiving the driving mode selection signal and fault information of the engine;
the judging module is used for judging whether the multi-stroke cycle mode entering condition is met or not according to the driving mode selection signal and the fault information;
the multi-stroke cycle mode determining module is used for matching the corresponding multi-stroke cycle mode and stroke combination according to the operation condition and the operation state information of the engine when the judging module judges that the multi-stroke cycle mode entering condition is met;
a control module to control the engine based on the determined multi-stroke cycle mode and the stroke combination, wherein the multi-stroke cycle engine further comprises an intake expansion stroke and an expansion stroke, wherein,
the expansion stroke is a process in which an intake valve and an exhaust valve are closed and a piston descends from a top dead center;
the suction expansion stroke refers to the process of opening an intake valve at proper time to suck a preset amount of air or mixture in the process of descending expansion of the piston from the top dead center,
the third stroke to the (N-1) th stroke are combined from the compression stroke, the power stroke, the suction-expansion stroke, and the expansion stroke, wherein,
a subsequent stroke immediately after the previous stroke is a compression stroke if the previous stroke among the third to (N-1) th strokes is a power stroke, an expansion stroke or a suction-expansion stroke;
a subsequent stroke immediately after the compression stroke is one of a power stroke, an expansion stroke, and a suction-expansion stroke if a previous stroke among the third to (N-1) th strokes is a compression stroke;
wherein the (N-1) th stroke is a power stroke or an expansion stroke.
6. The control system for the multi-stroke cycle engine of claim 5 wherein the operating conditions of the engine include a start condition, a warm-up condition, and a normal operating condition.
7. The control system for a multi-stroke cycle engine as claimed in claim 5 further comprising:
and when it is judged that the multi-stroke cycle mode entry condition is not satisfied, controlling the engine according to a conventional four-stroke cycle mode.
8. A vehicle, characterized in that a control system for a multi-stroke cycle engine as claimed in any one of claims 5-7 is provided.
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