阅读说明：本技术 直喷发动机的喷油控制方法、装置、电子设备和存储介质 (Fuel injection control method and device for direct injection engine, electronic equipment and storage medium ) 是由 彭浩 陈苏佑 李仕成 王星 胡必柱 于 2021-07-27 设计创作，主要内容包括：本申请实施例公开了一种直喷发动机的喷油控制方法、装置、电子设备和存储介质。直喷发动机的喷油控制方法包括获取直喷发动机的运行工况；根据直喷发动机的运行工况,确定直喷发动机的喷油时序；其中,喷油时序包括直喷发动机在每个工作周期内至少一次喷油的喷油时刻。本申请实施例能够根据直喷发动机的运行工况,来确定直喷发动机在每个工作周期内至少一次喷油的喷油时刻,使得直喷发动机能够根据运行工况,来调整每个工作周期内的喷油时刻,促进了燃油与气体的充分混合,提高燃油的燃烧率,减少直喷发动机的油耗,降低颗粒物的排放量。同时,还能够避免燃油碰壁冷凝,从而回流到曲轴箱中造成机油稀释,进一步提高了直喷发动机的使用可靠性。(The embodiment of the application discloses an oil injection control method and device of a direct injection engine, electronic equipment and a storage medium. The fuel injection control method of the direct injection engine comprises the steps of obtaining the operation condition of the direct injection engine; determining the fuel injection time sequence of the direct injection engine according to the operation condition of the direct injection engine; the injection sequence includes the injection time of at least one injection of the direct injection engine in each operating cycle. The embodiment of the application can determine the oil injection time of the direct injection engine at least once in each working period according to the operation condition of the direct injection engine, so that the oil injection time in each working period can be adjusted according to the operation condition of the direct injection engine, the full mixing of fuel oil and gas is promoted, the combustion rate of the fuel oil is improved, the oil consumption of the direct injection engine is reduced, and the emission of particulate matters is reduced. Meanwhile, the fuel can be prevented from colliding and condensing with the wall, so that the fuel flows back to the crankcase to dilute the engine oil, and the use reliability of the direct injection engine is further improved.)

1. A fuel injection control method of a direct injection engine, characterized by comprising:

acquiring the operation condition of the direct injection engine;

determining the fuel injection time sequence of the direct injection engine according to the operation condition of the direct injection engine;

wherein the injection schedule includes a time of injection of at least one injection per duty cycle of the direct injection engine.

2. The fuel injection control method of a direct injection engine according to claim 1, wherein said step of determining said fuel injection timing of said direct injection engine in accordance with an operation condition of said direct injection engine comprises:

determining the oil injection time of the first oil injection in each working period according to the operation condition of the direct injection engine; and/or

And determining the injection time of the last injection in each working period according to the operation condition of the direct injection engine.

3. The fuel injection control method of a direct injection engine according to claim 2, wherein the operating conditions of the direct injection engine include a start-up condition, a light-off condition, a warm-up condition, and a normal operating condition, and the step of determining the fuel injection timing of the first fuel injection in each of the operation cycles based on the operating conditions of the direct injection engine includes:

when the direct injection engine is in a starting working condition, controlling the crank angle of the first oil injection in each working period to be 220-270 degrees;

when the direct injection engine is in a light-off working condition, controlling the crank angle of the first oil injection in each working period to be 240-290 ℃;

when the direct injection engine is in a warm-up working condition, controlling the crank angle of the first oil injection in each working period to be 240-280 degrees;

and when the direct injection engine is in a normal operation condition, controlling the crank angle of the first injection in each work period to be 270-300 degrees.

4. The fuel injection control method of a direct injection engine according to claim 2, wherein said step of determining the timing of injection of the last injection in each of said duty cycles in accordance with the operating condition of said direct injection engine comprises:

when the direct injection engine is in a starting working condition, controlling the difference value between the crank angle of the last injection in each working period and the crank angle of the ignition in each working period to be between 15 and 40 degrees;

when the direct injection engine is in a light-off working condition, controlling the crank angle of the last oil injection in each working period to be 70-120 degrees;

and when the direct injection engine is in a warm-up working condition or a normal operation working condition, determining the crank angle of the last oil injection in each working period according to the crank angle of the first oil injection in each working period.

5. The fuel injection control method of a direct injection engine according to claim 1, characterized by further comprising, after said obtaining of the operating condition of said direct injection engine:

obtaining operating parameters of the direct injection engine;

and determining the injection times in each work period according to the operation parameters of the direct injection engine.

6. The fuel injection control method of a direct injection engine according to claim 5, characterized in that the operating parameter of the direct injection engine includes at least one of a rotational speed, a load, an injection pressure, and a minimum injection pulse width;

the step of determining the number of injections of the direct injection engine in each of the operating cycles based on the operating parameters of the direct injection engine comprises:

acquiring the rotating speed and the load;

determining the total fuel injection amount in each working period according to the rotating speed and the load;

acquiring the oil injection pressure and the minimum oil injection pulse width;

determining the minimum fuel injection quantity of single fuel injection of the direct injection engine according to the fuel injection pressure and the minimum fuel injection pulse width;

and determining the injection times in each working period according to the total injection quantity in each working period and the minimum injection quantity of the single injection of the direct injection engine.

7. The fuel injection control method of a direct injection engine according to claim 6, wherein said operating parameters of said direct injection engine further include setting a maximum number of fuel injections, and said step of determining said number of fuel injections per said operation period based on a total fuel injection amount per said operation period and a minimum fuel injection amount per a single fuel injection of said direct injection engine includes:

determining the expected oil injection times in each working period according to the total oil injection amount in each working period and the minimum oil injection amount of single oil injection of the direct injection engine;

acquiring the set maximum oil injection times;

judging whether the estimated oil injection times are smaller than the set maximum oil injection times or not;

when the predicted oil injection times are smaller than the set maximum oil injection times, taking the predicted oil injection times as the oil injection times in each working period;

and when the predicted oil injection times are larger than or equal to the set maximum oil injection times, taking the set maximum oil injection times as the oil injection times in each working period.

8. A fuel injection control device for a direct injection engine, characterized by comprising:

the acquisition device is used for acquiring the operation condition of the direct injection engine;

the fuel injection device is used for determining the fuel injection time sequence of the direct injection engine according to the operation condition of the direct injection engine;

wherein the injection schedule includes a time of injection of at least one injection per duty cycle of the direct injection engine.

9. An electronic device, characterized by comprising a processor, a memory and a program or instructions stored on said memory and executable on said processor, said program or instructions, when executed by said processor, implementing the steps of the fuel injection control method of a direct injection engine according to any one of claims 1 to 7.

10. A readable storage medium characterized in that the storage medium stores a program that, when executed, is capable of implementing the steps of the fuel injection control method of a direct injection engine according to any one of claims 1 to 7.

Technical Field

The embodiment of the application relates to the technical field of engines, in particular to an oil injection control method of a direct injection engine, an oil injection control device of the direct injection engine, electronic equipment and a storage medium.

Background

The engine mainly functions to convert chemical energy of fuel oil into mechanical energy so as to provide power for the whole vehicle. The direct injection engine can directly inject fuel into the cylinder, so that the fuel and gas are mixed in the cylinder to form combustible mixed gas.

In the related art, the direct injection engine usually injects oil into the cylinder according to the set oil injection time, and when the operation condition of the engine changes, the set oil injection time cannot meet the operation requirement of the direct injection engine, so that the fuel oil and the gas are not sufficiently mixed, the combustion rate of the fuel oil is reduced, and the emission of particulate matters is increased.

Disclosure of Invention

The embodiment of the application provides an oil injection control method of a direct injection engine, an oil injection control device of the direct injection engine, electronic equipment and a readable storage medium.

In a first aspect, an embodiment of the present application provides a fuel injection control method for a direct injection engine, including: acquiring the operation condition of the direct injection engine; determining the fuel injection time sequence of the direct injection engine according to the operation condition of the direct injection engine; the injection sequence includes the injection time of at least one injection of the direct injection engine in each operating cycle.

In one possible embodiment, the step of determining the injection timing of the direct injection engine based on the operating condition of the direct injection engine comprises: determining the oil injection time of the first oil injection in each working period according to the operating condition of the direct injection engine; and/or determining the injection time of the last injection in each working period according to the running working condition of the direct injection engine.

In one possible embodiment, the operation condition of the direct injection engine includes a start condition, a light-off condition, a warm-up condition, and a normal operation condition, and the step of determining the injection timing of the first injection in each operation period according to the operation condition of the direct injection engine includes: when the direct injection engine is in a starting working condition, controlling the crank angle of the first oil injection in each working period to be 220-270 degrees; when the direct injection engine is in a combustion starting working condition, controlling the crank angle of the first oil injection in each working period to be 240-290 ℃; when the direct injection engine is in a warm-up working condition, controlling the crank angle of the first oil injection in each working period to be 240-280 degrees; when the direct injection engine is in a normal operation condition, the crank angle of the first injection in each working period is controlled to be 270-300 degrees.

In one possible embodiment, the step of determining the injection time of the last injection in each operating cycle, based on the operating conditions of the direct injection engine, comprises: when the direct injection engine is in a starting working condition, controlling the difference value between the crank angle of the last oil injection in each working period and the crank angle of the ignition in each working period to be between 15 and 40 degrees; when the direct injection engine is in a combustion starting working condition, controlling the crank angle of the last oil injection in each working period to be between 70 and 120 degrees; and when the direct injection engine is in a warm-up working condition or a normal operation working condition, determining the crank angle of the last oil injection in each working period according to the crank angle of the first oil injection in each working period.

In one possible embodiment, after obtaining the operating condition of the direct injection engine, the method further includes: acquiring operating parameters of the direct injection engine; the number of injections per operating cycle is determined based on the operating parameters of the direct injection engine.

In one possible embodiment, the operating parameter of the direct injection engine comprises at least one of a rotational speed, a load, an injection pressure and a minimum injection pulse width; the step of determining the number of injections of the direct injection engine per operating cycle based on the operating parameters of the direct injection engine comprises: acquiring a rotating speed and a load; determining the total oil injection amount in each working period according to the rotating speed and the load; acquiring oil injection pressure and minimum oil injection pulse width; determining the minimum oil injection quantity of single oil injection of the direct injection engine according to the oil injection pressure and the minimum oil injection pulse width; and determining the injection times in each working period according to the total injection amount in each working period and the minimum injection amount of single injection of the direct injection engine.

In one possible embodiment, the operating parameters of the direct injection engine further comprise a set maximum number of injections, and the step of determining the number of injections per operating cycle on the basis of the total number of injections per operating cycle and the minimum number of injections per single injection of the direct injection engine comprises: determining the predicted oil injection times in each working period according to the total oil injection amount in each working period and the minimum oil injection amount of single oil injection of the direct injection engine; acquiring a set maximum oil injection frequency; judging whether the estimated oil injection times are smaller than the set maximum oil injection times or not; when the predicted oil injection times are smaller than the set maximum oil injection times, taking the predicted oil injection times as the oil injection times in each working period; and when the predicted injection times are larger than or equal to the set maximum injection times, taking the set maximum injection times as the injection times in each working period.

In a second aspect, an embodiment of the present application provides a fuel injection control device for a direct injection engine, the fuel injection control device for the direct injection engine being configured to control the direct injection engine, the fuel injection control device for the direct injection engine including: the acquisition device is used for acquiring the operation condition of the direct injection engine; the fuel injection device is used for determining the fuel injection time sequence of the direct injection engine according to the operation condition of the direct injection engine; the injection sequence includes the injection time of at least one injection of the direct injection engine in each operating cycle.

In a third aspect, the present embodiment provides an electronic device, including a processor, a memory, and a program or an instruction stored in the memory and executable on the processor, wherein the program or the instruction, when executed by the processor, implements the steps of the fuel injection control method of the direct injection engine according to the first aspect.

In a fourth aspect, embodiments of the present application provide a readable storage medium storing a program that, when executed, is capable of implementing the steps of the fuel injection control method for a direct injection engine of the first aspect.

The embodiment of the application has the following beneficial effects:

the embodiment of the application can determine the oil injection time of the direct injection engine at least once in each working period according to the operation condition of the direct injection engine, so that the direct injection engine can adjust the oil injection time in each working period according to the operation condition, the full mixing of fuel oil and gas is promoted, the combustion rate of the fuel oil is improved, the oil consumption of the direct injection engine is reduced, and the emission of particles is reduced. Meanwhile, the fuel can be prevented from colliding and condensing with the wall, so that the fuel flows back to the crankcase to dilute the engine oil, and the use reliability of the direct injection engine is further improved.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the application. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:

FIG. 1 is a flowchart illustrating steps of a method for controlling fuel injection in a direct injection engine according to an exemplary embodiment of the present disclosure;

FIG. 2 is a schematic diagram illustrating timing of fuel injection in a direct injection engine according to an embodiment of the present disclosure;

FIG. 3 is a second schematic diagram illustrating a timing sequence for fuel injection in a direct injection engine according to an embodiment of the present disclosure;

FIG. 4 is a third schematic timing diagram illustrating fuel injection timing for a direct injection engine according to an embodiment of the present disclosure;

FIG. 5 is a fourth schematic diagram illustrating injection timing for a direct injection engine according to an embodiment of the present disclosure;

FIG. 6 is a flowchart illustrating a second method step of controlling fuel injection in a direct injection engine according to an exemplary embodiment of the present disclosure;

FIG. 7 is a flowchart illustrating a third step of a fuel injection control method for a direct injection engine according to an exemplary embodiment of the present disclosure;

FIG. 8 is a flowchart illustrating a fourth step of a fuel injection control method for a direct injection engine according to an exemplary embodiment of the present disclosure;

FIG. 9 is a block diagram schematically illustrating an exemplary fuel injection control apparatus for a direct injection engine according to an embodiment of the present disclosure;

fig. 10 is a schematic diagram of the amount of particulate matter discharged from a direct injection engine according to an embodiment of the present disclosure.

Wherein, the correspondence between the reference numbers and the names of the components in fig. 9 is:

110: acquisition means, 120: an oil injection device.

Detailed Description

In order that the above objects, features and advantages of the present invention can be more clearly understood, a more particular description of the invention will be rendered by reference to the appended drawings. It should be noted that the embodiments and features of the embodiments of the present application may be combined with each other without conflict.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than those specifically described herein, and therefore the scope of the present invention is not limited by the specific embodiments disclosed below.

In a first aspect, as shown in fig. 1, an embodiment of the present application provides a fuel injection control method for a direct injection engine, including:

step S101, obtaining the operation condition of the direct injection engine;

and step S102, determining the fuel injection timing sequence of the direct injection engine according to the operation condition of the direct injection engine.

The injection sequence includes the injection time of at least one injection of the direct injection engine in each operating cycle.

The direct injection engine in the embodiment of the present application may be a four-cylinder direct injection engine. It is understood that a direct injection engine comprises an injection nozzle capable of injecting fuel into a cylinder of the direct injection engine so that the fuel mixes with the gas inside the cylinder.

Specifically, the direct injection engine includes an intake stroke, a compression stroke, a power stroke, and an exhaust stroke, and injects fuel in the intake stroke and/or the compression stroke. The injection timing of the direct injection engine is a timing at which the direct injection engine injects fuel in the intake stroke and/or the compression stroke.

Specifically, during the intake stroke, the intake valve of the direct injection engine opens and gas enters the cylinder. During the compression stroke, the intake valve closes and the piston moves, compressing the gas in the cylinder. In the power stroke, a spark plug of the direct injection engine ignites, compressed mixed gas is ignited, and a piston is pushed to move, so that the direct injection engine can output power to the vehicle. In the exhaust stroke, the exhaust valve opens and the piston moves to expel the gas from the cylinder. The intake stroke, compression stroke, power stroke and exhaust stroke of the direct injection engine add up to one working cycle.

It will be appreciated that within each operating cycle, a direct injection engine requires one or more injections to power the vehicle. When multiple injections are performed in each operating cycle, the injection quantity of each injection may be the same or different.

The operating condition of the direct injection engine is obtained, and understandably, the operating condition of the direct injection engine is related to the operating condition of the vehicle. The injection timing of the direct injection engine is determined based on the operating condition of the direct injection engine, wherein the injection timing comprises the injection time of at least one injection of fuel in each working cycle of the direct injection engine.

According to the operating condition of the direct injection engine, the oil injection time of at least one oil injection of the direct injection engine in each working period is determined, so that the oil injection time of the direct injection engine in each working period can be adjusted according to the operating condition, the full mixing of fuel oil and gas is promoted, the combustion rate of the fuel oil is improved, the oil consumption of the direct injection engine is reduced, and the emission of particles is reduced. Meanwhile, the fuel can be prevented from colliding and condensing with the wall, so that the fuel flows back to the crankcase to dilute the engine oil, and the use reliability of the direct injection engine is further improved.

In some examples, the injection timing of the first injection of fuel in each operating cycle of the direct injection engine may be determined based on the operating condition of the direct injection engine, and in some examples, the injection timing of the last injection of fuel in each operating cycle of the direct injection engine may also be determined based on the operating condition of the direct injection engine.

In some examples, whether the direct injection engine injects fuel or not can be controlled according to the rotation angle of the crankshaft, so that the control of the injection time of the direct injection engine is realized, and the accuracy of the control of the injection time is improved. In some examples, whether the direct injection engine injects fuel or not can be controlled according to the operation position of the piston, so that the control of the injection time of the direct injection engine is realized. In some examples, whether the direct injection engine injects fuel or not can be controlled by a timer or the like, so that the control of the injection time of the direct injection engine is realized.

In some examples, the step of determining a timing of injection of the direct injection engine based on an operating condition of the direct injection engine comprises:

determining the oil injection time of the first oil injection in each working period according to the operating condition of the direct injection engine; and/or

And determining the injection time of the last injection in each working period according to the operating condition of the direct injection engine.

According to the operating condition of the direct injection engine, the oil injection time of the first oil injection in each working period is determined, so that the oil injection time of the first oil injection in each working period can be matched with the operating condition, the full mixing of fuel oil and gas is promoted, the combustion rate of the fuel oil is improved, the emission of particulate matters is reduced, the oil consumption of the direct injection engine is reduced, and the use performance of the direct injection engine is improved.

In some examples, when multiple times of oil injection are required in each working period, the oil injection time of the rest of oil injections can be determined according to the oil injection time of the first oil injection, the oil injection pulse width, the time required for opening the oil injection nozzle and the like, so that the oil injection time confirmation efficiency is improved. As can be appreciated, the pulse width of the injection is the duration of a single injection event in a direct injection engine.

According to the operating condition of the direct injection engine, the oil injection time of the last oil injection in each working period is determined, so that the oil injection time of the last oil injection in each working period can be matched with the operating condition, and the stability of the operation of the direct injection engine under different working conditions is ensured.

In some examples, the fuel injection time of the last fuel injection can be controlled to be close to the ignition time of the direct injection engine, so that the concentration of fuel at the ignition time is increased, the fuel combustion is promoted, the particulate matter emission is reduced, and the service performance of the direct injection engine is improved.

In some examples, the operating conditions of the direct injection engine include a start condition, a light-off condition, a warm-up condition, and a normal operating condition.

The step of determining the injection timing of the first injection within each operating cycle based on the operating conditions of the direct injection engine includes:

when the direct injection engine is in a starting working condition, controlling the crank angle of the first oil injection in each working period to be 220-270 degrees;

when the direct injection engine is in a combustion starting working condition, controlling the crank angle of the first oil injection in each working period to be 240-290 ℃;

when the direct injection engine is in a warm-up working condition, controlling the crank angle of the first oil injection in each working period to be 240-280 degrees;

when the direct injection engine is in a normal operation condition, the crank angle of the first injection in each working period is controlled to be 270-300 degrees.

The operation conditions of the direct injection engine include a starting condition, a light-off condition, a warming-up condition and a normal operation condition. As can be appreciated, the direct injection engine is in the start condition after the vehicle is started. The direct injection engine enters a light-off condition after operating for a period of time at a start-up condition. When the direct injection engine operates between a period of the ignition working condition, the direct injection engine enters a warm-up working condition, and after the direct injection engine operates for a period of time under the warm-up working condition, the direct injection engine enters a normal operation working condition.

In some examples, the operating time of the direct injection engine may be the same or different for different operating conditions.

It will be appreciated that the crankshaft is connected to the piston and that the cylinder is able to complete an intake stroke as well as a compression stroke when the crankshaft completes a 360 rotation. The different crank angles correspond to different positions of the piston in the cylinder. In some examples, the crankshaft angle is 0 ° when the piston is at top dead center of the cylinder.

Specifically, the direct injection engine is in the compression stroke when the crank angle is between 0 ° and 180 °. The direct injection engine is in the intake stroke when the crank angle is between 180 ° and 360 °.

In some examples, the lower the water temperature of the direct injection engine, the smaller the crank angle at which the direct injection engine first injects fuel during each duty cycle. The greater the load on the direct injection engine, the smaller the crank angle at which the direct injection engine first injects fuel per duty cycle.

In some examples, the crankshaft angle at which the direct injection engine first injects fuel during each operating cycle may be between 220 ° and 320 °.

Specifically, as shown in fig. 2, when the direct injection engine is in the start condition, the crank angle of the first injection in each operation period may be controlled to be 220 ° to 270 °. As shown in FIG. 3, when the direct injection engine is in the light-off condition, the crank angle of the first injection during each operating cycle may be controlled to be between 240 and 290. As shown in FIG. 4, when the direct injection engine is in a warm-up condition, the crank angle of the first injection during each operating cycle may be controlled to be between 240 and 280. As shown in fig. 5, when the direct injection engine is in the normal operating condition, the crank angle of the first injection in each operation period may be controlled to be 270 ° to 300 °.

It can be understood that when the direct injection engine is in different working conditions, the first oil injection is carried out in the air inlet stroke of the direct injection engine, the mixing time of fuel oil and gas is prolonged, the fuel oil and the gas are promoted to be fully mixed, the combustion rate of the fuel oil is improved, the emission of particulate matters is reduced, and the oil consumption of the direct injection engine is reduced.

In addition, according to the different operating conditions of the direct injection engine, the difference of the crank angle of the first oil injection in each working period is set, namely the oil injection time of the direct injection engine is controlled through different crank angles, the accuracy of the direct injection engine for controlling the oil injection time is improved, other timing devices and the like are not required to be set, and the cost of the direct injection engine is reduced.

And, set up the crank angle of first oil spout in every duty cycle according to the operating condition of directly spouting the engine, can also make the crank angle of first oil spout in every duty cycle and the operating condition looks adaptation of directly spouting the engine, increased the mixing time of fuel and gas, promote fuel and gas to carry out intensive mixing, improve the combustion rate of fuel, reduce particulate matter and discharge to reduce the oil consumption of directly spouting the engine.

In some examples, when the direct injection engine is in the start condition, the crank angle of the first injection in each working period may be controlled to be 225 °, 235 ° or 255 ° or the like. When the direct injection engine is in the ignition working condition, the crank angle of the first injection in each working period can be controlled to be 245 degrees, 255 degrees, 265 degrees and the like. When the direct injection engine is in the warm-up condition, the crank angle of the first injection in each working period can be controlled to be 255 degrees, 265 degrees, 275 degrees and the like. When the direct injection engine is in a normal operation condition, the crank angle of the first oil injection in each work period can be controlled to be 275 degrees, 285 degrees or 295 degrees, and the like.

In some examples, the step of determining the injection timing of the last injection during each operating cycle based on the operating conditions of the direct injection engine comprises:

when the direct injection engine is in a starting working condition, controlling the difference value between the crank angle of the last oil injection in each working period and the crank angle of the ignition in each working period to be between 15 and 40 degrees;

when the direct injection engine is in a combustion starting working condition, controlling the crank angle of the last oil injection in each working period to be between 70 and 120 degrees;

and when the direct injection engine is in a warm-up working condition or a normal operation working condition, determining the crank angle of the last oil injection in each working period according to the crank angle of the first oil injection in each working period.

It is understood that the crank angle at which ignition is performed is the timing at which ignition is performed by the direct injection engine. The crank angle at which ignition occurs in each operating cycle may be the same or different under different operating conditions of the direct injection engine.

In some examples, the crank angle of ignition may be between-20 ° and 40 °, specifically, ignition may be performed during operation of the piston from the bottom dead center to the top dead center, and ignition may also be performed during operation of the piston from the top dead center to the bottom dead center, so that ignition requirements of the direct injection engine under different operating conditions are met, and flexibility of use of the direct injection engine is improved. Specifically, the crank angle of ignition may be 15 °, 20 °, 25 °, or the like.

It will be appreciated that during start-up conditions, the value obtained by subtracting the crank angle at which the last injection occurred during each operating cycle from the crank angle at which the ignition occurred during each operating cycle is the difference between the crank angle at which the last injection occurred during each operating cycle and the crank angle at which the ignition occurred during each operating cycle. Specifically, as shown in fig. 2, when the direct injection engine is in the start-up condition, the difference between the crank angle of the last injection in each operation period and the crank angle of ignition in each operation period may be controlled to be between 15 ° and 40 °.

It can be understood that the crank angle of the last oil injection in each working period is larger than the crank angle of the ignition, that is, the last oil injection is carried out before the ignition, so that the fuel oil of the last oil injection can be diffused to the position near the spark plug, the fuel oil concentration near the spark plug is further increased, the fuel oil concentration near the spark plug is higher than the fuel oil concentration at other positions in the cylinder, the layered combustion of the mixed gas is realized, the combustion effect of the mixed gas is improved, the stability of the direct injection engine under the starting working condition is ensured, and the service performance of the direct injection engine is further ensured.

In some examples, when the engine is in the start condition, the difference between the crank angle of the last injection in each operating cycle and the crank angle of ignition in each operating cycle may be controlled to be 20 °, 25 °, 35 °, or the like.

In some examples, the crank angle EOI of the last injection per duty cycle at start-up conditions may be between 15 and 30. In some examples, the crank angle EOI of the last injection during each operating cycle at start-up conditions may be 18, 20, or 28.

As shown in fig. 3, when the direct injection engine is in the ignition condition, the crank angle of the last injection in each working cycle can be controlled to be between 70 ° and 120 °, that is, the last injection is performed in the compression stroke of the direct injection engine, so as to reduce the temperature in the cylinder, thereby reducing the occurrence of knocking in the cylinder and further improving the usability of the direct injection engine.

In some examples, the crank angle of the last injection during each operating cycle may be controlled to be 80, 90, 100, 110, etc. when the engine is in the light-off condition.

As shown in fig. 4 and 5, when the direct injection engine is in the warm-up condition or the normal operation condition, the crank angle of the last injection in each operation period may be determined according to the crank angle of the first injection in each operation period. Specifically, when the engine is in a warm-up working condition or a normal operation working condition, the crank angle of the last oil injection can be determined according to the crank angle of the first oil injection in each working period, the oil injection pulse width, the time required for opening the oil injection nozzle and the like.

For example, under the warm-up condition, the crank angle of the first oil injection in each working period may be 270 °, the oil injection pulse width of the direct injection engine is 5 °, the crank angle of the oil injection nozzle during the opening process is 2 °, the crank angle of the second oil injection is 270 ° +5 ° +2 ° -277 °, the crank angle of the third oil injection is 277 ° +5 ° +2 ° -284 °, so that the crank angle of the last oil injection in each working period can be sequentially calculated, the confirmation efficiency of the crank angle is improved, and the accuracy of the obtained crank angle of the last oil injection is improved.

In some examples, as shown in fig. 6, after obtaining the operating condition of the direct injection engine, the method further includes:

step S201, acquiring operation parameters of the direct injection engine;

step S202, according to the operation parameters of the direct injection engine, the number of times of oil injection in each work period is determined.

The method comprises the steps of obtaining an operation parameter of the direct injection engine, wherein the operation parameter of the direct injection engine is specifically an operation parameter corresponding to the working condition of the direct injection engine. According to the operating parameters of the direct injection engine, the oil injection frequency in each working period is determined, so that the oil injection frequency in each working period can be matched with the operating parameters of the direct injection engine, the full mixing of fuel oil and gas is further promoted, the combustion effect of the fuel oil is improved, the emission of particulate matters is reduced, the oil consumption of the direct injection engine is reduced, and the use performance of the direct injection engine is improved.

In some examples, as shown in FIG. 7, the operating parameter of the direct injection engine includes at least one of a speed, a load, an injection pressure, and a minimum injection pulsewidth.

The step of determining the number of injections of the direct injection engine per operating cycle based on the operating parameters of the direct injection engine comprises:

step S301, acquiring a rotating speed and a load;

step S302, determining the total amount of oil injection in each working period according to the rotating speed and the load;

step S303, acquiring oil injection pressure and minimum oil injection pulse width;

step S304, determining the minimum oil injection quantity of single oil injection of the direct injection engine according to the oil injection pressure and the minimum oil injection pulse width;

and step S305, determining the injection times in each work period according to the total injection amount in each work period and the minimum injection amount of single injection of the direct injection engine.

The rotation speed and the load of the direct injection engine are obtained, and specifically the rotation speed and the load of the direct injection engine are the rotation speed and the load corresponding to the operation condition of the direct injection engine. The power of the direct injection engine can be obtained according to the rotating speed and the load of the direct injection engine, and the fuel demand amount of the direct injection engine in each working period, namely the total fuel injection amount of the direct injection engine in each working period can be calculated according to the power and the heat efficiency of the direct injection engine.

It will be appreciated that the total amount of fuel injected per cycle may be the total mass of fuel injected per cycle of the direct injection engine, or the total volume of fuel injected per cycle of the direct injection engine.

And acquiring the fuel injection pressure and the minimum fuel injection pulse width of the direct injection engine, wherein the fuel injection pressure is the fuel injection pressure corresponding to the operation condition of the direct injection engine, and the minimum fuel injection pulse width is the minimum fuel injection duration of single fuel injection of the direct injection engine under the fuel injection pressure. According to the oil injection pressure and the minimum oil injection pulse width, the minimum oil injection quantity of single oil injection of the direct injection engine can be obtained.

And according to the total oil injection amount in each working period and the minimum oil injection amount of single oil injection of the direct injection engine, the oil injection frequency of the direct injection engine in each working period can be obtained.

It is understood that the minimum injected quantity of a single injection may be the minimum injected mass of a single injection, or may be the minimum injected volume of a single injection.

The fuel injection total amount in each working period is obtained through the rotating speed and the load of the direct injection engine, the minimum fuel injection amount of single fuel injection is obtained through the fuel injection pressure and the minimum fuel injection pulse width, the fuel injection times of the direct injection engine in each working period are obtained through the fuel injection total amount in each working period and the minimum fuel injection amount of single fuel injection, the accuracy of the obtained fuel injection times is improved, the fuel injection times in each working period are increased, fuel can be fully mixed with gas, the fuel combustion efficiency is ensured, and the fuel consumption of the direct injection engine is reduced.

In some examples, as shown in FIG. 8, the operating parameters of the direct injection engine further include setting a maximum number of injections.

The step of determining the number of injections per operating cycle on the basis of the total number of injections per operating cycle and the minimum number of injections per single injection of the direct injection engine comprises:

step S401, determining the expected oil injection times in each working period according to the total oil injection amount in each working period and the minimum oil injection amount of single oil injection of the direct injection engine;

step S402, acquiring a set maximum oil injection frequency;

step S403, judging whether the predicted oil injection times are less than the set maximum oil injection times;

step S404, when the predicted oil injection times are smaller than the set maximum oil injection times, taking the predicted oil injection times as the oil injection times in each working period;

in step S405, when the predicted fuel injection times are larger than or equal to the set maximum fuel injection times, the set maximum fuel injection times are used as the fuel injection times in each work period.

And determining the predicted injection times in each work period according to the total injection amount in each work period and the minimum injection amount of single injection of the direct injection engine. Specifically, the total fuel injection amount of the direct injection engine in each working period is divided by the number of cylinders of the direct injection engine to obtain the fuel injection amount of each cylinder in each working period, and then the fuel injection amount of each cylinder in each working period is divided by the minimum fuel injection amount of the single fuel injection to obtain the expected fuel injection times of the direct injection engine in each working period.

The set maximum number of injections is obtained, which, as will be understood, is the maximum number of times that the injector of the direct injection engine can be opened during each operating cycle.

And judging whether the predicted oil injection frequency is smaller than the set maximum oil injection frequency or not, and if the predicted oil injection frequency is smaller than the set maximum oil injection frequency, taking the predicted oil injection frequency as the oil injection frequency in each working period, so that the oil injection frequency in each working period can be increased on the basis of not exceeding the preset maximum oil injection frequency, and the fuel oil and the gas are promoted to be fully mixed while the operation reliability of the direct injection engine is improved.

If the estimated oil injection times are larger than or equal to the set maximum oil injection times, the set maximum oil injection times are used as the oil injection times in each working period, the oil injection nozzle damage caused by the fact that the oil injection times in each period exceed the set maximum oil injection times is avoided, and the use reliability of the direct injection engine is further improved.

In some examples, when the predicted number of fuel injections is greater than or equal to the set maximum number of fuel injections, the fuel injection amount of a single fuel injection is adjusted according to the set maximum number of fuel injections to avoid insufficient fuel amount in each working period, thereby further improving the reliability of the fuel injection control method of the direct injection engine.

In some examples, the total amount of fuel injected during each cycle may be divided by the minimum amount of fuel injected during a single injection to yield the same amount of fuel injected during each injection.

In a second aspect, as shown in fig. 9, the present embodiment provides a fuel injection control device for a direct injection engine, the fuel injection control device for the direct injection engine is used for controlling the direct injection engine, and the fuel injection control device for the direct injection engine comprises an acquisition device 110 and a fuel injection device 120. The obtaining means 110 is used for obtaining the operation condition of the direct injection engine. The fuel injection device 120 is used for determining the fuel injection timing of the direct injection engine according to the operation condition of the direct injection engine. The injection sequence includes the injection time of at least one injection of the direct injection engine in each operating cycle.

The fuel injection control device of the direct injection engine in the embodiment of the present application can realize the steps of the fuel injection control method of the direct injection engine of the first aspect, and therefore, has all the advantages of the first aspect, and will not be described herein again.

In a third aspect, an embodiment of the present application provides an electronic device, which includes a processor, a memory, and a program or an instruction stored in the memory and executable on the processor, where the program or the instruction, when executed by the processor, implements the steps of the fuel injection control method for the direct injection engine according to the first aspect, and therefore has all the advantages of the first aspect, and details of the steps are not repeated here.

In a fourth aspect, embodiments of the present application provide a readable storage medium, which stores a program, and when the program is executed, the steps of the fuel injection control method for a direct injection engine according to the first aspect can be implemented, so that all the advantages of the first aspect are achieved, and details are not repeated herein.

In one embodiment, a fuel injection control method for a direct injection engine is provided. The method comprises the steps of obtaining the operation condition of the direct injection engine, wherein the operation condition of the direct injection engine comprises a starting condition, a combustion starting condition, a warming condition and a normal operation condition. The method comprises the steps of obtaining corresponding operation parameters of the direct injection engine under operation conditions, determining the number of times of oil injection of the direct injection engine in each working period according to the operation parameters, and determining the crank angle of at least one time of oil injection of the direct injection engine in each working period.

Specifically, the rotation speed and the load of the direct injection engine are obtained, and the total fuel injection amount of the direct injection engine in each work period is calculated according to the rotation speed and the load. And acquiring the oil injection pressure and the minimum oil injection pulse width of the direct injection engine, and calculating the minimum oil injection quantity of single oil injection according to the oil injection pressure and the minimum oil injection pulse width.

Taking a four-cylinder direct injection engine as an example, the total fuel injection amount mtotal in each working period is divided by four to obtain the total fuel injection amount mtotal/4 of each cylinder in each working period. And dividing the total oil injection amount of each cylinder in each working period by the minimum oil injection amount mmin of single oil injection to obtain the predicted oil injection frequency mtotal/4 mmin.

The set maximum number of fuel injections nmax is obtained, and the set maximum number of fuel injections nmax is the maximum number of fuel injections approved by EMS (Engine Management System). And taking the smaller value of the predicted injection time mtotal/4mmin and the set maximum injection time nmax as the injection time n of the direct injection engine in each working period.

After the oil injection times n in each working period are determined, dividing the total oil injection amount mtotal/4 of each cylinder in each working period by the oil injection times n in each working period to obtain the oil injection amount of each cylinder in each working period in a single oil injection mode, and enabling the oil injection amount of each oil injection to be the same.

Taking the number of times n of fuel injection per cylinder per one operation period as an example, as shown in fig. 2, in the starting operation, the first three times of fuel injection timing are set in the intake stroke per one operation period. Specifically, under the starting condition, the crank angle SOI of the first oil injection in each working period is 270 °, and the crank angle of the second oil injection is equal to the crank angle SOI of the first oil injection in each working period + the continuous crank angle Edur of each oil injection + the crank angle Emin required for opening each oil injection nozzle. And the crank angle of the third oil injection is equal to the crank angle of the second oil injection plus the continuous crank angle Edur of each oil injection plus the crank angle Emin required by opening each oil injection nozzle.

Specifically, the single injection duration may be calculated according to the injection pressure, the single injection amount, the injection flow rate, and the like, and the continuous crank angle Edur of each injection may be obtained according to the single injection duration. The crank angle Emin required for each opening of the oil injection nozzle can be obtained by converting the time required for each opening of the oil injection nozzle.

Under the starting condition, the crank angle EOI of the last injection in each working period is determined according to the crank angle of ignition. In some examples, the crank angle of ignition is 10 °, the crank angle required for fuel to be delivered to the spark plug is determined to be about 15 ° by simulation model calculation, so that the crank angle EOI of the last fuel injection in each working cycle is set to 10 ° +15 ° -25 °, so that the fuel is just ignited when the fuel is delivered to the spark plug, the fuel concentration near the spark plug is high, and the fuel concentration in other regions is low, so that the mixed gas can form stratified combustion, the starting stability of the direct injection engine is improved, the combustion rate of the fuel is improved, and the fuel consumption of the direct injection engine is reduced.

Specifically, as shown in fig. 10, in the light-off condition, when the crank angle of the last injection is constant in each operation period, different injection times and different crank angle SOI of the first injection correspond to different amounts of particulate matter discharged. Specifically, the crank angle EOI of the last injection may be set to be between 60 ° and 160 ° to perform two injections, or the crank angle EOI of the last injection may be set to be between 60 ° and 140 ° to perform three injections. It will be appreciated that in three injections, the crank angle EOI of the last injection in each operating cycle is between 60 ° and 140 °, and the crank angle SOI of the first injection in each operating cycle is around 270 °, the amount of particulate matter emitted is minimal.

As shown in FIG. 3, during the light-off condition, the first three injection timings are set during the intake stroke. Specifically, the crank angle SOI of the first injection in each operating cycle is 270 °, and the crank angle of the second injection is the crank angle SOI of the first injection in each operating cycle + the continuous crank angle Edur of each injection + the crank angle Emin required for opening each injection nozzle. And the crank angle of the third oil injection is equal to the crank angle of the second oil injection plus the continuous crank angle Edur of each oil injection plus the crank angle Emin required by opening each oil injection nozzle.

During the light-off condition, the injection angle EOI of the last injection per operating cycle may be set between 70 and 120, and in some examples, the injection angle EOI of the last injection per operating cycle may be set between 90 and 100.

As shown in fig. 4, in the warm-up condition, four injections are all placed in the intake stroke, specifically, the crank angle SOI of the first injection in each operating period is 270 °, and the crank angle of the second injection is equal to the crank angle SOI of the first injection in each operating period + the continuous crank angle Edur of each injection + the crank angle Emin required for opening each injection nozzle. And the crank angle of the third oil injection is equal to the crank angle of the second oil injection plus the continuous crank angle Edur of each oil injection plus the crank angle Emin required by opening each oil injection nozzle. The crank angle of the fourth injection is the crank angle of the third injection plus the continuous crank angle Edur of each injection plus the crank angle Emin required for opening each injection nozzle.

As shown in fig. 5, under normal operating conditions, four injections are all placed in the intake stroke, specifically, the crank angle SOI of the first injection in each operating cycle is 300 °, and the crank angle of the second injection is equal to the crank angle SOI of the first injection in each operating cycle + the continuous crank angle Edur of each injection + the crank angle Emin required for opening each injection nozzle. And the crank angle of the third oil injection is equal to the crank angle of the second oil injection plus the continuous crank angle Edur of each oil injection plus the crank angle Emin required by opening each oil injection nozzle. The crank angle of the fourth injection is the crank angle of the third injection plus the continuous crank angle Edur of each injection plus the crank angle Emin required for opening each injection nozzle.

By setting the crank angle of the first oil injection in each working period, the crank angles at other oil injection moments can be obtained, and the confirming efficiency of the crank angles is improved.

The embodiment of the application can promote the sufficient mixing of fuel and gas, avoids the fuel to bump the wall condensation and causes the machine oil dilution, improves the combustion rate of fuel, reduces the emission of particulate matter, reduces the oil consumption of directly spouting the engine.

Compared with the related art, the fuel consumption can be reduced by 14% to 25%, and the emission of gases such as hydrocarbons and carbon monoxide can be reduced by 20%. In a high-pressure injection system at 350bar, the particulate matter emissions are below 1E + 11.

In the present invention, the terms "first", "second", and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance; the term "plurality" means two or more unless expressly limited otherwise. The terms "mounted," "connected," "fixed," and the like are to be construed broadly, and for example, "connected" may be a fixed connection, a removable connection, or an integral connection; "coupled" may be direct or indirect through an intermediary. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "left", "right", "front", "rear", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the referred device or unit must have a specific direction, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.

In the description herein, the description of the terms "one embodiment," "some embodiments," "specific embodiments," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.