Engine torque control method and control device for a hybrid vehicle

Abstract

An engine torque control method for a hybrid vehicle, specifically comprising: condition recognition, recognizing a fast-torque trigger condition indicating insufficient generator torque reduction capability when a stepped-on accelerator pedal is released; fast-torque intervention, intervening actual engine torque with engine fast torque at a target fast-torque value when the fast-torque trigger condition is met; and fast-torque exit, stopping the intervention of engine fast torque when a fast-torque exit condition is met. The engine torque control method can improve engine response characteristics of the hybrid vehicle. An engine torque control device for a hybrid vehicle is also involved.

Description

Technical Field

[0001] This invention relates to the field of hybrid vehicle technology. Specifically, this invention relates to an engine torque control method and control device for hybrid vehicles. Background Technology

[0002] Against the backdrop of increasingly prominent energy and environmental issues, new energy vehicles are receiving more and more attention. Hybrid vehicles with a P1+P3 layout are a commonly used type of new energy vehicle. Figure 1 A schematic diagram of the powertrain system of a hybrid vehicle with this layout is shown. The generator GM is connected to the rear end of the engine E (internal combustion engine, ICE) and the front end of the clutch K0, i.e., position P1; the drive motor DM is connected to the rear end of the transmission, i.e., position P3. When the clutch K0 is disengaged, the drive motor DM can directly drive the vehicle, and the generator GM can recover torque from the engine E to generate electricity. When the clutch K0 is engaged, the engine E and the generator GM, along with the drive motor DM, drive the vehicle together via the clutch K0.

[0003] In hybrid vehicles, as the driver presses the accelerator, the demand for torque increases, the battery discharges, and the torque and speed of the engine (E) rise. When the accelerator is released, the driver's torque demand first drops to zero and then becomes negative (the generator (GM) recovers energy). At this point, it's necessary to reduce the engine's speed and torque, ideally requiring the electric motor to output negative torque to help reduce speed. In this situation, the generator (GM) has negative torque and positive speed. The generator (GM) has negative power, and the battery is charging. Under normal circumstances, the battery has a large charging capacity, which can quickly reduce the engine's torque and speed. However, some special conditions may limit the battery's charging capacity, such as excessive battery charge or environmental conditions affecting charging power. In these cases, the generator (GM) may not be able to output enough negative torque to offset the engine's torque, causing the engine to reach very high speeds and generate significant noise. This problem is widespread, especially in low-temperature environments where battery charging capacity is limited. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to provide an engine torque control method for improving the engine response characteristics of hybrid vehicles.

[0005] The aforementioned technical problem is solved by an engine torque control method for a hybrid vehicle according to the present invention. The hybrid vehicle includes a power system comprising a generator that introduces the power system between an engine and a clutch, and a drive motor that introduces the power system at the rear end of a transmission. The power system is controlled by the accelerator pedal of the hybrid vehicle. The engine torque control method includes:

[0006] Operating condition identification, including identifying the fast torque trigger condition that indicates insufficient torque reduction capability of the generator when the accelerator pedal is released;

[0007] Quick torque intervention, wherein, when the quick torque triggering condition is met, the engine's actual torque is intervened using the target quick torque value with the engine's quick torque; and

[0008] Quick torque disengagement, whereby, when the quick torque disengagement condition is met, the intervention of engine quick torque is stopped.

[0009] According to a preferred embodiment of the present invention, the fast torque triggering condition can be that the maximum absolute value of the negative torque that the generator is allowed to output to the engine is less than the current actual torque of the engine. The maximum absolute value of the negative torque that the generator is allowed to output to the engine is equal to the product of the current maximum allowable absolute value of the generator's output negative torque and the speed ratio from the engine to the generator.

[0010] According to another preferred embodiment of the invention, the target fast torque value can be the smaller of the maximum absolute value of the negative torque that the generator is allowed to output to the engine (E) and the target torque requested by the engine for slow torque, minus a predetermined value. Preferably, the predetermined value can be 0.3-0.5.

[0011] According to another preferred embodiment of the present invention, the fast torque exit condition can be that the difference between the maximum torque of the engine in response to the slow torque request and the maximum absolute value of the negative torque that the generator is allowed to output to the engine is less than a predetermined difference.

[0012] According to another preferred embodiment of the present invention, the step of fast twist intervention may include activating a flag bit when the fast twist triggering condition is met; and the step of fast twist exit may include resetting the flag bit when the fast twist exit condition is met.

[0013] According to another preferred embodiment of the present invention, the engine torque control method can be executed by the vehicle controller of the hybrid vehicle.

[0014] The aforementioned technical problem is solved by an engine torque control device for a hybrid vehicle according to the present invention. The hybrid vehicle includes a power system comprising a generator that introduces the power system between an engine and a clutch, and a drive motor that introduces the power system at the rear end of a transmission. The power system is controlled by the accelerator pedal of the hybrid vehicle. The engine torque control device includes:

[0015] The operating condition identification module is configured to identify fast torque triggering conditions that indicate insufficient torque reduction capability of the generator when the depressed accelerator pedal is released.

[0016] The fast torque intervention module is configured to intervene in the engine's actual torque by using engine fast torque at a target fast torque value when the fast torque triggering condition is met; and

[0017] The fast torque exit module is configured to stop intervening in engine fast torque when the fast torque exit conditions are met.

[0018] According to a preferred embodiment of the present invention, the working condition identification module can be configured as follows:

[0019] Compare the maximum absolute value of the negative torque that the generator is allowed to output to the engine with the engine's current actual torque;

[0020] The fast torque triggering condition is identified as being met when the maximum absolute value of the negative torque that the generator is allowed to output to the engine is less than the current actual torque of the engine.

[0021] According to another preferred embodiment of the present invention, the fast torque intervention module may include a determining unit configured to determine the smaller of the maximum absolute value of the negative torque that the generator is allowed to output to the engine and the target torque requested by the engine by subtracting a predetermined value, respectively, as the target fast torque value.

[0022] According to another preferred embodiment of the present invention, the quick-release module can be configured as follows:

[0023] Calculate the difference between the maximum torque the engine can deliver in response to a slow torque request and the maximum absolute value of the negative torque that the generator is allowed to output to the engine, and compare this difference with a predetermined difference.

[0024] When the difference is less than the predetermined difference, it is identified as meeting the quick-twist exit condition.

[0025] According to another preferred embodiment of the present invention, the working condition identification module may include an activation unit configured to activate a flag bit when the fast torque triggering condition is met; and the fast torque exit module may include a reset unit configured to reset the flag bit when the fast torque exit condition is met. Attached Figure Description

[0026] The invention is further described below with reference to the accompanying drawings. In the drawings, the same reference numerals represent elements with the same function. Wherein:

[0027] Figure 1 A schematic diagram of a power system applying an engine torque control method according to an exemplary embodiment of the present invention is shown;

[0028] Figure 2 A flowchart illustrating the steps of an engine torque control method according to an exemplary embodiment of the present invention is shown; and

[0029] Figure 3a and Figure 3b Response curves of an engine torque control method according to the prior art and an engine torque control method according to an exemplary embodiment of the present invention are shown respectively. Detailed Implementation

[0030] The following describes specific embodiments of the engine torque control method and control device for hybrid vehicles according to the present invention, with reference to the accompanying drawings. The detailed description and drawings below are provided to exemplify the principles of the invention; the invention is not limited to the described preferred embodiments, and the scope of protection of the invention is defined by the claims.

[0031] According to an embodiment of the present invention, an engine torque control method for a hybrid vehicle is provided. Figure 1 A schematic diagram of the powertrain system of this hybrid vehicle is shown. Figure 1 As shown, the powertrain includes an engine E, a generator GM, a clutch K0, a transmission T, a differential D, a drive motor DM, a battery, and wheels W. The generator GM is introduced into the powertrain at position P1 between the engine E and the clutch K0. The generator GM can recover the kinetic energy of the engine E to generate electricity and can supply the generated electricity to the battery. The battery can power the drive motor DM. The drive motor DM is introduced into the powertrain at position P3 at the rear of the transmission and can directly drive the wheels W. This powertrain is controlled by the accelerator pedal (not shown) of the hybrid vehicle.

[0032] To enable the engine to quickly reduce torque and speed when the driver releases the accelerator, the following method is used to control engine torque.

[0033] like Figure 2 As shown in the step diagram, firstly, operating condition identification is performed in step S1. Specifically, when the depressed accelerator pedal is released, a fast torque triggering condition indicating insufficient torque reduction capability of the generator GM is identified.

[0034] Here, the fast torque triggering condition indicating insufficient torque reduction capability of the generator GM refers to a situation where the battery charging power is insufficient for the generator GM to output sufficient negative torque to reduce the torque of the engine E. The fast torque triggering condition needs to be dynamically determined based on the current actual torque of the engine E and the negative torque that the generator GM can output to the engine E. Specifically, if the negative torque that the generator GM can output to the engine E can cover the current actual torque of the engine E, there is no need to activate the engine fast torque; otherwise, the engine fast torque needs to be activated. Since the negative torque output by the generator GM to the engine E is negative while the actual torque of the engine E is positive, this means that the fast torque triggering condition is when the maximum absolute value of the negative torque that the generator GM is allowed to output to the engine E is less than the current actual torque of the engine E. Here, the maximum absolute value of the negative torque that the generator GM is allowed to output to the engine E is equal to the product of the current maximum allowable absolute value of the generator GM's output negative torque and the speed ratio from the engine E to the generator GM.

[0035] If the fast torque triggering condition is identified in step S1, the control method will initiate step S2 to intervene in the fast torque. In step S2, when the fast torque triggering condition is met, the engine fast torque is used to intervene in the actual torque of engine E with the target fast torque value.

[0036] Preferably, in step S2, a flag bit can be activated when the fast torque triggering condition is met, and then fast torque intervention is initiated based on the activated flag bit. Here, the flag bit indicates the torque control mode of engine E. The flag bit typically has two states: triggered and non-triggered, corresponding to the engine fast torque control mode controlled by the engine's firing circuit and the engine slow torque control mode controlled by the engine's air circuit, respectively. The activated flag bit corresponds to the engine fast torque control mode controlled by the engine's firing circuit. After intervention using engine fast torque, engine E can quickly respond to the driver's torque demand by reducing torque and speed.

[0037] Preferably, the target fast torque value is the smaller of the maximum absolute value of the negative torque that the generator GM is allowed to output to the engine E and the target torque requested by the engine E by subtracting a predetermined value. This predetermined value can be a small number, such as 0.3-0.5.

[0038] Next, in step S3, the fast torque is disengaged. Specifically, fast torque does not need to be continuously intervened; after the fast torque intervention is initiated, the intervention is stopped when the fast torque disengagement conditions are met.

[0039] The fast torque exit condition specifically refers to the fact that when the current maximum airflow torque of engine E after fast torque intervention is close to the maximum absolute value of the negative torque that generator GM is allowed to output to engine E, the flag can be reset to a non-triggered state. The airflow torque of engine E refers to the torque that engine E responds to a slow torque request. In other words, the fast torque exit condition is that the difference between the maximum torque of engine E responding to a slow torque request and the maximum absolute value of the negative torque that generator GM is allowed to output to engine E is less than a predetermined difference. As long as the predetermined difference is sufficiently small, it means that the two values ​​are sufficiently close when the fast torque exit condition is met. At this point, the torque and speed of engine E can be basically controlled solely by the negative torque output of generator GM.

[0040] Preferably, the flag can be reset when the above-mentioned fast torque exit conditions are met. Therefore, the triggered flag is reset to a non-triggered state, ending the fast torque intervention. Afterwards, engine E re-enters the slow torque control state.

[0041] The aforementioned engine torque control method can be executed by the vehicle controller of the hybrid vehicle. The various data required to execute this control method can be obtained from the existing sensors in the hybrid vehicle, thus eliminating the need for additional components.

[0042] According to an embodiment of the present invention, an engine torque control device for a hybrid vehicle is also provided. This engine torque control device can accordingly execute the above-described engine torque control method, and is also applicable to... Figure 1 The powertrain system of the hybrid vehicle shown is illustrated. The control unit can be composed of functional modules within the vehicle controller. This control unit includes a condition identification module, a high-torque intervention module, and a high-torque deactivation module.

[0043] The operating condition identification module is used to execute step S1, and is configured to identify the fast torque trigger condition when the depressed accelerator pedal is released. Preferably, the operating condition identification module is configured to compare the maximum absolute value of the negative torque that the generator GM is allowed to output to the engine E with the current actual torque of the engine E to determine whether the fast torque trigger condition is met; if the maximum absolute value of the negative torque that the generator GM is allowed to output to the engine E is less than the current actual torque of the engine E, it is identified as meeting the fast torque trigger condition. Preferably, the operating condition identification module may further include an activation unit, which is configured to activate a flag bit when the fast torque trigger condition is met.

[0044] The fast torque intervention module is used to execute step S2, and is configured to intervene in the actual torque of engine E by using engine fast torque at a target fast torque value when the fast torque triggering condition is met. Preferably, the fast torque intervention module may include a determining unit. The determining unit is configured to determine the target fast torque value as the smaller of the maximum absolute value of the negative torque that generator GM is allowed to output to engine E and the target torque requested by engine E by slow torque minus a predetermined value.

[0045] The fast torque exit module is used to execute step S3, and is configured to stop the intervention of engine fast torque when the fast torque exit condition is met. Preferably, the fast torque exit module can be configured to calculate the difference between the maximum torque of engine E in response to slow torque request and the maximum absolute value of the negative torque that generator GM is allowed to output to engine E, and compare the difference with a predetermined difference to determine whether the fast torque exit condition is met; if the difference is less than the predetermined difference, it is identified as meeting the fast torque exit condition. Preferably, the fast torque exit module may further include a reset unit, which is configured to reset a flag bit when the fast torque exit condition is met.

[0046] By comparison Figure 3a The response curves of existing technologies and Figure 3b As can be seen from the response curve of the present invention, using the control method and control device according to the present invention, when the driver presses and then releases the accelerator pedal, the entire response process of the engine E's torque and speed is very smooth, without any sudden jumps in engine speed. This not only improves the engine's NVH (noise, vibration, and harshness) performance but also provides the driver with a good driving experience. Furthermore, this control method and control device can accurately determine conditions where the battery's charging power is limited, preventing battery damage due to overcharging.

[0047] While possible embodiments have been described exemplarily in the foregoing description, it should be understood that numerous variations of embodiments exist through combinations of all known and readily conceived technical features and implementation methods. Furthermore, it should be understood that the exemplary embodiments are merely examples and do not in any way limit the scope, application, or construction of the invention. The foregoing description is more intended to provide those skilled in the art with technical guidance for transforming at least one exemplary embodiment, wherein various changes, particularly regarding the function and structure of the components, can be made without departing from the scope of the claims.

[0048] Appendix Label Table

[0049] E engine

[0050] K0 Clutch

[0051] D differential

[0052] DM drive motor

[0053] GM generator

[0054] T transmission

[0055] W wheel

Claims

1. A method for controlling engine torque in a hybrid vehicle, the hybrid vehicle comprising a power system including a generator (GM) introduced between an engine (E) and a clutch (KO) and a drive motor (DM) introduced at the rear end of a transmission, the power system being controlled by an accelerator pedal of the hybrid vehicle, characterized in that, The engine torque control method includes: Operating condition identification (S1), wherein when the depressed accelerator pedal is released, a fast torque triggering condition indicating insufficient torque reduction capability of the generator (GM) is identified; Quick torque intervention (S2), wherein, when the quick torque triggering condition is met, engine quick torque is used to intervene in the actual torque of the engine (E) with a target quick torque value; and Quick torque disengagement (S3) means that when the quick torque disengagement condition is met, the intervention of engine quick torque is stopped.

2. The engine torque control method according to claim 1, characterized in that, The fast torque triggering condition is that the maximum absolute value of the negative torque that the generator (GM) is allowed to output to the engine (E) is less than the current actual torque of the engine (E).

3. The engine torque control method according to claim 2, characterized in that, The target fast torque value is the smaller of the maximum absolute value of the negative torque that the generator (GM) is allowed to output to the engine (E) and the target torque requested by the engine (E) by subtracting a predetermined value.

4. The engine torque control method according to claim 3, characterized in that, The predetermined value is 0.3-0.

5.

5. The engine torque control method according to claim 1, characterized in that, The fast torque exit condition is that the difference between the maximum torque of the engine (E) in response to the slow torque request and the maximum absolute value of the negative torque that the generator (GM) is allowed to output to the engine (E) is less than a predetermined difference.

6. The engine torque control method according to claim 1, characterized in that, The fast-twitch intervention (S2) step includes activating a flag bit when the fast-twitch trigger condition is met; and The quick-twist exit (S3) step includes resetting the flag bit when the quick-twist exit condition is met.

7. The engine torque control method according to any one of claims 1 to 6, characterized in that, The engine torque control method is executed by the vehicle controller of the hybrid vehicle.

8. An engine torque control device for a hybrid vehicle, the hybrid vehicle including a power system comprising a generator (GM) introduced between an engine (E) and a clutch (KO) and a drive motor (DM) introduced at the rear end of a transmission, the power system being controlled by an accelerator pedal of the hybrid vehicle, characterized in that, The engine torque control device includes: The operating condition identification module is configured to identify a fast torque triggering condition indicating insufficient torque reduction capability of the generator (GM) when the depressed accelerator pedal is released. A fast torque intervention module, configured to intervene in the actual torque of the engine (E) by using engine fast torque at a target fast torque value when the fast torque triggering condition is met; and The fast torque exit module is configured to stop intervening in engine fast torque when the fast torque exit conditions are met.

9. The engine torque control device according to claim 8, characterized in that, The operating condition identification module is configured as follows: Compare the maximum absolute value of the negative torque that the generator (GM) is allowed to output to the engine (E) with the current actual torque of the engine (E); The fast torque triggering condition is identified as being met when the maximum absolute value of the negative torque that the generator (GM) is allowed to output to the engine (E) is less than the current actual torque of the engine (E).

10. The engine torque control device according to claim 9, characterized in that, The fast torque intervention module includes a determining unit configured to determine the smaller of the maximum absolute value of the negative torque that the generator (GM) is allowed to output to the engine (E) and the target torque requested by the engine (E) by subtracting a predetermined value, respectively, as the target fast torque value.

11. The engine torque control device according to claim 8, characterized in that, The quick-exit module is configured as follows: Calculate the difference between the maximum torque of the engine (E) in response to a slow torque request and the maximum absolute value of the negative torque that the generator (GM) is allowed to output to the engine (E), and compare the difference with a predetermined difference. When the difference is less than a predetermined difference, it is identified as meeting the fast-torque exit condition.

12. The engine torque control device according to any one of claims 8 to 11, characterized in that, The operating condition identification module includes an activation unit, which is configured to activate a flag bit when the fast-twitch trigger condition is met; and The quick-twist exit module includes a reset unit, which is configured to reset the flag bit when the quick-twist exit condition is met.

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