A method and system for adaptive control of ramp torque

Abstract

The present application discloses a method and system for adaptive control of ramp torque; the method comprises: when the engine speed is greater than the starter exit speed, start timing; according to at least one of the engine speed change rate and the engine excess air coefficient, judge that the engine meets the ramp torque activation condition; when the timing time is greater than the preset time, the engine has not started yet, activate the ramp torque to assist the engine start; avoid the problem of inappropriate time for activating the ramp torque due to the different time to reach the starter exit speed due to the difference in cold start performance of different diesel engines; avoid the problem of activating the ramp torque when it is not necessary. The method for adaptive control of ramp torque provided by the present application can activate the ramp torque under more appropriate circumstances, ensure the smooth start of the engine, and reduce emissions during the start phase.

Description

Technical Field

[0001] The present application relates to the field of engine technology, and in particular to a method and system for adaptive control of ramp torque. Background Art

[0002] Starting performance is one of the important indicators to measure the performance of diesel engines. The starting injection amount is a key factor affecting the starting performance. If the starting injection amount of the diesel engine is set too small, the starting process cannot be completed smoothly; if the starting injection amount of the diesel engine is set too large, the fuel economy and emission characteristics will be reduced.

[0003] In current electronic control logic, a torque-based fuel injection quantity calculation and conversion method is often used. The starting torque required at different temperatures is determined through experiments, and the starting fuel injection quantity is obtained based on the conversion relationship between the oil quantity and the starting torque.

[0004] In order to ensure reliable starting effect, ramp torque is introduced into the electronic control strategy. Ramp torque is a kind of auxiliary starting torque. When the cumulative engine rotation time reaches the set value, if the starting cannot be completed, the ramp torque is enabled to quickly increase the injection amount.

[0005] However, there are differences in the cold start performance of diesel engines of different models, and the activation condition of the ramp torque is only that the cumulative time of engine rotation reaches a set value. Therefore, there is a problem of inappropriate activation of the ramp torque. Summary of the invention

[0006] In view of this, the present application provides a method and system for adaptive control of ramp torque, which can appropriately enable the ramp torque, ensure smooth starting of the engine, and reduce emissions during the starting phase.

[0007] To solve the above problems, the technical solutions provided by this application are as follows:

[0008] The present application provides a method for ramp torque adaptive control, the method comprising:

[0009] When the engine speed is greater than the starter exit speed, the timing starts;

[0010] determining, based on at least one of a rate of change of engine speed and an excess air coefficient of the engine, that the engine meets a ramp torque enabling condition;

[0011] When the timing time is greater than the preset time and the engine has not started, the ramp torque is activated to assist the engine starting.

[0012] Preferably, judging whether the engine meets the ramp torque enabling condition according to at least one of the engine speed change rate and the engine excess air coefficient includes:

[0013] According to the engine speed change rate being less than or equal to the preset change rate, it is determined that the engine meets the ramp torque activation condition.

[0014] Preferably, judging whether the engine meets the ramp torque enabling condition according to at least one of the engine speed change rate and the engine excess air coefficient includes:

[0015] Based on the fact that the excess air coefficient of the engine is within a preset range, it is determined that the engine meets the ramp torque activation condition.

[0016] Preferably, judging whether the engine meets the ramp torque enabling condition according to at least one of the engine speed change rate and the engine excess air coefficient includes:

[0017] According to the engine speed change rate being less than or equal to a preset change rate and the engine excess air coefficient being within a preset range, it is determined that the engine meets the ramp torque activation condition.

[0018] Preferably, the excess air coefficient is calculated by the intake air amount and the fuel injection amount.

[0019] The present application also provides a ramp torque adaptive control system, comprising: a timer, a controller and an engine;

[0020] A timer, used to start timing when the engine speed is greater than the starter exit speed;

[0021] The controller is used to determine whether the engine meets the ramp torque activation condition according to at least one of the engine speed change rate and the engine excess air coefficient; when the timing time is greater than the preset time and the engine has not started, the ramp torque is activated to assist the engine in starting;

[0022] The engine is used to start according to the control of the controller.

[0023] Preferably, the controller is specifically used to determine whether the engine meets the ramp torque activation condition based on the engine speed change rate being less than or equal to a preset change rate.

[0024] Preferably, the controller is specifically configured to determine whether the engine meets the ramp torque enabling condition based on an excess air coefficient of the engine being within a preset range.

[0025] Preferably, the controller is specifically used to determine whether the engine meets the ramp torque activation condition based on the engine speed change rate being less than or equal to a preset change rate and the engine excess air coefficient being within a preset range.

[0026] Preferably, the excess air coefficient is calculated by the intake air amount and the fuel injection amount.

[0027] It can be seen that this application has the following beneficial effects:

[0028] The method of ramp torque adaptive control provided by the present application starts timing from when the engine speed is greater than the starter exit speed, and judges that the engine meets the ramp torque activation condition based on at least one of the engine speed change rate and the engine's excess air coefficient; when the timing time is greater than the preset time, the engine has not started yet, and the ramp torque is activated. Starting timing from when the engine speed is greater than the starter exit speed avoids the problem of inappropriate time for activating the ramp torque due to different times to reach the starter exit speed due to differences in cold start performance of different diesel engines; judging that the engine meets the ramp torque activation condition based on at least one of the engine speed change rate and the engine's excess air coefficient can avoid the problem of activating the ramp torque when it is not necessary. The method of ramp torque adaptive control provided by the present application can activate the ramp torque under more appropriate circumstances, ensure smooth engine starting, and reduce emissions during the starting phase. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic diagram of a diesel engine cold start process;

[0030] Figure 2 A flow chart of a method for adaptive control of ramp torque provided in an embodiment of the present application;

[0031] Figure 3 A schematic diagram of a ramp torque adaptive control system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0032] In order to more clearly understand the various embodiments of the present application, the cold start process of the diesel engine is briefly described below.

[0033] See also Figure 1 , which is a schematic diagram of a diesel engine cold start process.

[0034] The diesel engine is compression ignited. When starting, the starter first drives the engine flywheel to rotate, and the engine speed gradually increases. When the engine speed reaches the starter exit speed, it means that the flywheel drives the piston past the compression top dead center, and the gas pressure in the cylinder can spontaneously drive the crankshaft to do work, without the starter continuing to provide external force. However, due to reasons such as insufficient combustion, the work done by the engine may be equal to the work done by the resistance, resulting in the engine speed remaining constant and failing to start smoothly. At this time, the engine can enable ramp torque, quickly increase the amount of fuel injection, increase the engine work, speed up to complete the start, and improve the starting performance of the diesel engine.

[0035] In traditional technology, when the cumulative time of engine rotation reaches the set value, if the engine cannot complete the start, the ramp torque is enabled. However, the cold start performance of diesel engines of different models varies, and the time to reach the starter exit speed also varies; when the engine speed quickly reaches the starter exit speed, it is still necessary to wait for the cumulative time to reach the set value before the ramp torque can be enabled. The ramp torque is enabled too late, resulting in poor engine starting performance; when the engine speed reaches the starter exit speed slowly, if the cumulative time has reached the set value, the ramp torque is directly enabled, which may be enabled when it is not needed, resulting in excessive fuel injection and poor emissions during the starting phase.

[0036] The method of ramp torque adaptive control provided in the present application starts timing from the time when the engine speed is greater than the starter exit speed, and determines whether the engine meets the ramp torque activation conditions, and then activates the ramp torque. This method can appropriately activate the ramp torque, ensure smooth starting of the engine, and reduce emissions during the starting phase.

[0037] In order to enable those skilled in the art to better understand and implement the technical solution of the present application, the embodiments of the present application are described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0038] See also Figure 2 , which is a flow chart of the method for slope torque adaptive control provided in an embodiment of the present application.

[0039] The method includes:

[0040] S201: When the engine speed is greater than the starter exit speed, start timing.

[0041] The starter exit speed refers to the engine speed when the starter drives the engine flywheel to rotate until the engine can spontaneously perform work and the starter needs to exit.

[0042] Different diesel engines have different cold start performances, and the time to reach the starter exit speed is also different. Therefore, starting the timing from when the engine speed is greater than the starter exit speed can eliminate the factors of cold start performance differences and enable ramp torque at a more appropriate time.

[0043] S202: Determine whether the engine meets the ramp torque activation condition based on at least one of the engine speed change rate and the engine excess air coefficient.

[0044] For example, the engine can be judged to meet the ramp torque activation condition based on at least one of the engine speed change rate being less than or equal to a preset change rate and the engine excess air coefficient being within a preset range. This application does not specifically limit the specific values ​​of the preset change rate and the preset range.

[0045] The engine speed change rate is small, which means that the engine speed basically remains constant. At this time, the work done by the engine and the work done by the resistance are balanced, and it is difficult for the engine to start. Therefore, it is necessary to enable ramp torque, increase the fuel injection amount, increase the engine work, and ensure that the engine starts smoothly. The engine speed change rate is large, which means that the engine speed has a clear upward trend and can complete the start. Therefore, there is no need to enable ramp torque, which reduces unnecessary fuel injection and reduces emissions during the starting phase.

[0046] The present application does not specifically limit the method for obtaining the excess air coefficient. For example, it can be calculated through the intake air volume and the injection fuel volume, or it can be obtained by other methods.

[0047] The excess air coefficient is not within the standard range, indicating that the current ratio of intake air volume to fuel injection volume is unqualified, resulting in incomplete combustion of fuel, low engine power, and failure to start smoothly. At this time, ramp torque cannot be enabled. For example, if ramp torque is enabled when the fuel injection volume is too small, it can only increase a portion of the fuel injection volume, and the engine may still fail to start; for example, if ramp torque is enabled when the intake air volume is small and the fuel injection volume is too large, the fuel injection volume is further increased, and the engine cannot start either; at this time, return to adjust the intake air volume and fuel injection volume.

[0048] The excess air coefficient is within the standard range, indicating that the ratio of intake air volume to fuel injection volume is appropriate, and the engine cannot start normally due to the above reasons. If the engine still cannot start at this time, enable ramp torque, increase fuel injection volume, increase engine work, and ensure that the engine starts smoothly.

[0049] The engine speed change rate and excess air coefficient are both used to determine whether the current state of the engine requires the activation of ramp torque. Only one of them can be determined, which makes the control logic simple; or both can be determined to enable ramp torque more accurately.

[0050] S203: If the timing time is greater than the preset time and the engine has not started yet, the ramp torque is activated to assist the engine starting.

[0051] The present application does not specifically limit the specific value of the preset time. In order to avoid the ramp torque being enabled too late, the preset time should not be too long. Preferably, it can be 3 seconds; of course, it can also be other values.

[0052] When the timing time is greater than the preset time, the engine has not started yet, and after the judgment in step S202, it is indicated that the engine needs to enable the ramp torque, therefore, the ramp torque is enabled, the injection amount is increased, and the engine starting is assisted.

[0053] The method of ramp torque adaptive control provided by the present application starts timing from when the engine speed is greater than the starter exit speed, and judges that the engine meets the ramp torque activation condition based on at least one of the engine speed change rate and the engine's excess air coefficient; when the timing time is greater than the preset time, the engine has not started yet, and the ramp torque is activated. Starting timing from when the engine speed is greater than the starter exit speed avoids the problem of inappropriate time for activating the ramp torque due to different times to reach the starter exit speed due to differences in cold start performance of different diesel engines; judging that the engine meets the ramp torque activation condition based on at least one of the engine speed change rate and the engine's excess air coefficient can avoid the problem of activating the ramp torque when it is not necessary. The method of ramp torque adaptive control provided by the present application can activate the ramp torque under more appropriate circumstances, ensure smooth engine starting, and reduce emissions during the starting phase.

[0054] Based on the slope torque adaptive control method provided in the above embodiments, the embodiment of the present application further provides a slope torque adaptive control system, which is described in detail below with reference to the accompanying drawings.

[0055] See also Figure 3 , which is a schematic diagram of a ramp torque adaptive control system provided in an embodiment of the present application.

[0056] The ramp torque adaptive control system provided in the embodiment of the present application includes: a timer 100 , a controller 200 and an engine 300 .

[0057] The timer 100 is used to start timing when the engine speed is greater than the starter exit speed.

[0058] The controller 200 is used to determine whether the engine meets the ramp torque activation condition based on at least one of the engine speed change rate and the engine excess air coefficient; when the timing time is greater than the preset time and the engine has not started, the ramp torque is activated to assist the engine starting.

[0059] The engine 300 is used to start according to the control of the controller 200 .

[0060] The present application does not specifically limit the specific value of the preset time. In order to avoid the ramp torque being enabled too late, the preset time should not be too long. Preferably, it can be 3 seconds; of course, it can also be other values.

[0061] The present application does not specifically limit the method for obtaining the excess air coefficient. For example, it can be calculated through the intake air volume and the injection fuel volume, or it can be obtained by other methods.

[0062] Among them, the controller 200 can be specifically used to judge that the engine meets the ramp torque activation condition based on the engine speed change rate being less than or equal to the preset change rate; it can also be specifically used to judge that the engine meets the ramp torque activation condition based on the engine excess air coefficient being within a preset range; it can also be specifically used to judge that the engine meets the ramp torque activation condition based on the engine speed change rate being less than or equal to the preset change rate and the engine excess air coefficient being within a preset range.

[0063] The ramp torque adaptive control system provided by the present application, the timer starts timing when the engine speed is greater than the starter exit speed, and the controller determines that the engine meets the ramp torque activation condition based on at least one of the engine speed change rate and the engine's excess air coefficient; when the timing time is greater than the preset time, the engine has not started, the controller activates the ramp torque, and the engine starts according to the control of the controller. The timer starts timing when the engine speed is greater than the starter exit speed, avoiding the problem of inappropriate time for activating the ramp torque due to the difference in cold start performance of different diesel engines and the different time to reach the starter exit speed; the controller determines that the engine meets the ramp torque activation condition based on at least one of the engine speed change rate and the engine's excess air coefficient, and can determine whether the engine needs the ramp torque, avoiding the problem of activating the ramp torque when it is not necessary. The ramp torque adaptive control system provided by the present application, the controller can activate the ramp torque under more appropriate circumstances, ensure the smooth start of the engine, and reduce emissions during the start phase.

[0064] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referred to each other. For the system or device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description.

[0065] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for adaptive control of ramp torque, characterized in that: The method includes: When the engine speed is greater than the starter exit speed, the timing starts, wherein the starter exit speed is the speed at which the engine can spontaneously perform work driven by the starter; According to the speed change rate of the engine and the preset change rate, or the excess air coefficient of the engine is within a preset range, it is determined that the engine meets the ramp torque activation condition; When the timing time is greater than the preset time, the engine has not started yet, and the ramp torque is enabled to assist the engine starting, where the ramp torque is a torque used to assist the engine starting.

2. The method according to claim 1, characterized in that: The determining that the engine meets the ramp torque enabling condition according to the engine speed change rate and the preset change rate, or the engine excess air coefficient being within a preset range, includes: According to the engine speed change rate being less than or equal to the preset change rate, it is determined that the engine meets the ramp torque activation condition.

3. The method according to claim 1, characterized in that The determining that the engine meets the ramp torque enabling condition according to the engine speed change rate and the preset change rate, or the engine excess air coefficient being within a preset range, includes: According to the fact that the speed change rate of the engine is less than or equal to the preset change rate and the excess air coefficient of the engine is within the preset range, it is determined that the engine meets the ramp torque activation condition.

4. The method according to claim 1 or 3, characterized in that: The excess air coefficient is calculated by the intake air amount and the injection fuel amount.

5. A ramp torque adaptive control system, characterized in that: include: timers, controllers and engines; The timer is used to start timing when the engine speed is greater than the starter exit speed, and the starter exit speed is the speed at which the engine can spontaneously do work driven by the starter; The controller is used to determine whether the engine meets the ramp torque activation condition according to the engine speed change rate and the preset change rate, or the engine excess air coefficient is within a preset range; When the timing time is greater than the preset time, the engine has not started yet, the ramp torque is activated to assist the engine starting, and the ramp torque is a torque used to assist the engine starting; The engine is used to start according to the control of the controller.

6. The system according to claim 5, characterized in that The controller is specifically used to determine that the engine meets the ramp torque activation condition according to the engine speed change rate being less than or equal to the preset change rate.

7. The system according to claim 5, characterized in that The controller is specifically used to determine that the engine meets the ramp torque activation condition according to the engine speed change rate being less than or equal to the preset change rate and the engine excess air coefficient being within the preset range.

8. The system according to claim 5 or 7, characterized in that: The excess air coefficient is calculated by the intake air amount and the injection fuel amount.

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