Engine start control method and device for hybrid vehicle

Abstract

The present disclosure relates to an engine start control method and device for a hybrid vehicle, the method comprising: after completing the current start of the engine, determining whether start time data of the engine in the current start satisfies a predetermined condition; if the predetermined condition is satisfied, calculating a first coefficient according to the start time data; determining whether the clutch torque capacity adaptation amount for the current start of the engine needs to be adjusted according to the first coefficient; and if the adjustment is needed, adjusting the clutch torque capacity adaptation amount according to the first coefficient and a predetermined compensation amount, and storing the adjusted clutch torque capacity adaptation amount, wherein the adjusted clutch torque capacity adaptation amount is used for the next start of the engine. In this way, the clutch torque capacity adaptation amount can be avoided from being adjusted frequently, not only the robustness of the adjustment of the clutch torque capacity adaptation amount can be enhanced, but also the service life of the storage device for storing the clutch torque capacity adaptation amount can be prolonged.

Description

Technical Field

[0001] This disclosure relates to the field of hybrid electric vehicle technology, and in particular to an engine start control method and device for a hybrid electric vehicle. Background Technology

[0002] In related technologies, during the engine start-up process of a hybrid electric vehicle, the clutch torque capacity increases at a reasonable rate to a constant clutch torque capacity, and the clutch partially engages to transmit the constant clutch torque capacity to the engine, thereby adjusting the engine speed to a threshold speed lower than the drive motor speed. Summary of the Invention

[0003] In view of this, the present disclosure proposes an engine start control method and device for hybrid electric vehicles.

[0004] According to one aspect of this disclosure, an engine start-up control method for a hybrid electric vehicle is provided, the hybrid electric vehicle including an engine, a drive motor, and a clutch disposed between the engine and the drive motor, the engine start-up control method including:

[0005] The first judgment step is used to determine whether the start-up time data of the engine in this start-up meets the predetermined conditions after the engine is started.

[0006] The first calculation step is used to calculate a first coefficient based on the startup time data if it is determined that the startup time data meets the predetermined conditions.

[0007] The second judgment step is used to determine, based on the first coefficient, whether it is necessary to adjust the clutch torque capacity adaptation amount for this engine start-up; and

[0008] The adjustment step is used to adjust the clutch torque capacity adaptation amount according to the first coefficient and the predetermined compensation amount if it is determined that the clutch torque capacity adaptation amount needs to be adjusted, and to store the adjusted clutch torque capacity adaptation amount, wherein the adjusted clutch torque capacity adaptation amount is used for the next start of the engine.

[0009] According to another aspect of this disclosure, an engine start control device for a hybrid electric vehicle is provided, the hybrid electric vehicle including an engine, a drive motor, and a clutch disposed between the engine and the drive motor, the engine start control device including:

[0010] The first judgment module is used to determine whether the start-up time data of the engine in this start-up meets the predetermined conditions after the engine is started.

[0011] The first calculation module is used to calculate a first coefficient based on the startup time data if it is determined that the startup time data meets the predetermined conditions.

[0012] The second judgment module is used to determine, based on the first coefficient, whether it is necessary to adjust the clutch torque capacity adaptation amount for this engine start; and

[0013] An adjustment module is used to adjust the clutch torque capacity adaptation amount according to the first coefficient and a predetermined compensation amount if it is determined that the clutch torque capacity adaptation amount needs to be adjusted, and to store the adjusted clutch torque capacity adaptation amount, wherein the adjusted clutch torque capacity adaptation amount is used for the next start of the engine.

[0014] According to the hybrid electric vehicle engine start control method and apparatus disclosed herein, each time the engine starts, if the engine start time data in this start meets predetermined conditions, a first coefficient is calculated based on the start time data. The first coefficient is used to determine whether the clutch torque capacity adaptation amount for this engine start needs to be adjusted. The clutch torque capacity adaptation amount is only adjusted if the first coefficient determines that the clutch torque capacity adaptation amount needs to be adjusted. This avoids frequent adjustments to the clutch torque capacity adaptation amount, thereby effectively preventing unstable starting torque caused by frequent adjustments to the clutch torque capacity adaptation amount, and thus enhancing the robustness of the clutch torque capacity adaptation amount adjustment.

[0015] In addition, since frequent adjustments to the clutch torque capacity can be avoided, frequent changes in the data in the storage device caused by frequent adjustments to the clutch torque capacity can be effectively avoided, thereby reducing the number of erase / write cycles of the storage device and extending its lifespan.

[0016] Other features and aspects of this disclosure will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0017] The accompanying drawings, which are included in and form part of this specification, illustrate exemplary embodiments, features, and aspects of this disclosure together with the specification and serve to explain the principles of this disclosure.

[0018] Figure 1 This is a schematic diagram of the powertrain structure of a hybrid electric vehicle in related technologies.

[0019] Figure 2 This is a schematic diagram of the engine start-up process of a hybrid electric vehicle with a P2 module in related technologies.

[0020] Figure 3 This is a schematic diagram of the engine start-up process of a hybrid electric vehicle with a P2 module in related technologies.

[0021] Figure 4 This is a schematic diagram illustrating the start-up time of the engine start-up process in a hybrid electric vehicle with a P2 module in related technologies.

[0022] Figure 5 This is a schematic diagram illustrating the changes in clutch torque capacity adaptation involved in the self-learning process in related technologies.

[0023] Figure 6 This is a flowchart illustrating an engine start-up control method for a hybrid electric vehicle according to an exemplary embodiment.

[0024] Figure 7 This is a schematic diagram comparing the changes in clutch torque capacity adaptation during the self-learning process of the engine start control method after applying this embodiment and related technologies.

[0025] Figure 8 This is a block diagram illustrating an engine start control device for a hybrid electric vehicle according to an exemplary embodiment. Detailed Implementation

[0026] Various exemplary embodiments, features, and aspects of this disclosure will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0027] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0028] Furthermore, to better illustrate this disclosure, numerous specific details are set forth in the following detailed description. Those skilled in the art will understand that this disclosure can be practiced without certain specific details. In some instances, methods, means, components, and circuits well known to those skilled in the art have not been described in detail in order to highlight the main points of this disclosure.

[0029] As described in the background section, during the engine start-up process of a hybrid electric vehicle, the clutch torque capacity increases at a reasonable rate to a constant clutch torque capacity, and the clutch partially engages to transmit this constant clutch torque capacity to the engine, thereby adjusting the engine speed to a threshold speed below the drive motor speed.

[0030] In some cases, such as when the engine's frictional torque is higher than average due to low coolant temperature, or when the actual clutch torque is lower than required due to severe wear, the difference between the resultant force used to pull the engine speed—that is, the clutch torque and the engine's frictional torque—is less than normal. This results in a longer time required for the engine to reach the threshold speed, thus delaying the total engine start-up time.

[0031] To address the aforementioned issues, related technologies involve increasing the clutch torque capacity used for the current start if the engine start time exceeds an acceptable limit; conversely, decreasing the clutch torque capacity used for the current start if the engine start time falls short of the acceptable limit, and storing this clutch torque capacity in a storage device such as an EEPROM for use on the next start. In this way, upon the next start, the stored clutch torque capacity is retrieved, and the required clutch torque capacity is calculated based on this retrieved value, ensuring that the engine speed reaches the threshold speed promptly.

[0032] However, even when the starting time of the engine is slightly longer or shorter than acceptable due to some unforeseen factors (such as fluctuations in engine coolant temperature or clutch temperature), it is still necessary to reduce or increase the clutch torque capacity adaptation. This causes the clutch torque capacity adaptation to be used for the next engine start to change frequently, resulting in unstable starting torque and frequent changes in the data in the storage device, thereby increasing the number of times the storage device can be erased and rewritten, and thus shortening the life of the storage device.

[0033] To better understand the above issues, the following will combine... Figures 1 to 5 Let's elaborate on that.

[0034] Figure 1 This is a schematic diagram of the powertrain structure of a hybrid electric vehicle in related technologies. For example... Figure 1 As shown, the hybrid vehicle includes an engine, a P2 module, and a gearbox. The P2 module includes a K0 clutch and a drive motor. The P2 module is located between the engine and the gearbox, and the K0 clutch is located between the engine and the drive motor.

[0035] Figure 2 This is a schematic diagram of the engine start-up process in a hybrid electric vehicle with a P2 module, as described in related technologies. Figure 2As shown, the engine start-up process goes through stages P1, P2 and P3 in sequence. During the entire engine start-up process, the engine state (i.e. the operating state issued by the engine controller) is successively the stop state, start state and run state.

[0036] like Figure 2 As shown, in stage P1, the clutch torque capacity increases at a reasonable rate to a constant clutch torque capacity M, and the k0 clutch partially engages to transmit this constant clutch torque capacity to the engine, thereby adjusting the engine speed to a threshold speed lower than the drive motor speed. During this period, since the engine has not yet started, the engine torque capacity is 0. When the engine speed is higher than this threshold speed, stage P2 is entered.

[0037] In stage P2, the engine starts (ignites), and the clutch torque capacity decreases at a reasonable rate until the clutch is fully disengaged, thus preventing vehicle jerking caused by subsequent direct clutch engagement. Since the engine is already running, the engine torque capacity is not zero, and the engine speed is adjusted based on this torque capacity.

[0038] In stage P3, the clutch torque capacity increases at a reasonable rate, the k0 clutch partially engages to transmit the clutch torque capacity to the engine, thereby adjusting the engine speed to be close to the drive motor speed. When the engine speed and the drive motor speed are basically the same, the k0 clutch is fully engaged, and the engine speed curve and the drive motor speed curve basically overlap, that is, engine speed synchronization processing is performed.

[0039] However, in certain situations, such as when the engine's frictional torque is higher than average due to low coolant temperature, or when the actual torque of the K0 clutch is less than required due to severe wear, the resultant force required to raise the engine speed (this resultant force = actual torque of the K0 clutch - engine frictional torque) becomes less than normal. This results in a longer time required for the engine to reach the threshold speed, thus delaying the total engine start-up time. Even worse, in some extreme cases, the engine's frictional torque may exceed the actual torque of the K0 clutch, making it impossible to raise the engine speed and thus preventing successful engine start-up.

[0040] Indicatively, Figure 3 This is a schematic diagram of the engine start-up process of a hybrid electric vehicle with a P2 module in related technologies, such as... Figure 3 As shown, it takes more time for the engine speed to reach the threshold speed, and the engine start time is delayed from P2' to P2. Correspondingly, the time when the engine speed reaches the drive motor speed is also delayed.

[0041] To ensure the engine speed reaches the threshold speed in a timely manner, it is advisable to appropriately increase the constant clutch torque capacity M, such as... Figure 3 As shown, clutch k0 uses a larger clutch torque capacity M1 to pull the engine speed. Specifically, in stage P1, the constant clutch torque capacity M is increased by a clutch torque capacity adaptation amount ΔM calculated by a self-learning strategy to obtain an adjusted larger clutch torque capacity M1 (i.e., M1 = M + ΔM).

[0042] In related technologies, the self-learning strategy includes: if the engine starts for too long in this start-up, the clutch torque capacity adaptation for this start-up is increased, and the increased clutch torque capacity adaptation is used as the clutch torque capacity adaptation for the next start-up; if the engine starts for too short in this start-up, the clutch torque capacity adaptation for this start-up is decreased, and the decreased clutch torque capacity adaptation is used as the clutch torque capacity adaptation for the next start-up.

[0043] In one possible implementation, if the engine starts too long during the current start-up, the formulas △M'=△M+△ML and △ML=KL*(T3–(T2+△t2)) / t0 are used to calculate and store the clutch torque capacity adaptation △M' to be used for the next engine start-up. △M is the clutch torque capacity adaptation used for the current engine start-up, △ML is the torque capacity to be increased, KL is the torque adjustment coefficient, T2 is the acceptable engine start-up time, T2+△t2 represents the upper limit of the start-up time, T3 is the start-up time of the current engine start-up, and t0 is the time unit.

[0044] In one possible implementation, if the engine start-up time in this start is too short, the formulas △M'=△M-△Ms and △Ms=Ks*(T2-△t1–T1) / t0 are used to calculate and store the clutch torque capacity adaptation amount △M' to be used for the next engine start. △M is the clutch torque capacity adaptation amount used for the current engine start, △Ms is the torque capacity to be reduced, Ks is the torque adjustment coefficient, T2 is the acceptable engine start time, T2-△t1 represents the lower limit of the start time, T1 is the start time of the current engine start, and t0 is the time unit.

[0045] Figure 4 This is a schematic diagram illustrating the start-up time of the engine start-up process in a hybrid electric vehicle with a P2 module, as described in related technologies. Figure 4As shown, the threshold torque capacity is T0 and the threshold speed is N0. Curves L1, L2, and L3 correspond to the three engine start-up curves, respectively. The start-up times T1, T2, and T3 for curves L1, L2, and L3 are the time intervals from when the clutch torque capacity reaches the threshold torque capacity T0 until the engine speed reaches the threshold speed N0. Start-up time T1 is less than start-up time T2, and start-up time T2 is less than start-up time T3. Start-up time T2 is the acceptable engine start-up time, with an upper limit of T2 + Δt2 and a lower limit of T2 - Δt1. Therefore, when the start-up time is greater than the lower limit T2 - Δt1 and less than the upper limit T2 + Δt2, there is no need to adjust the clutch torque capacity adaptation for this engine start.

[0046] Figure 5 This is a schematic diagram illustrating the change in clutch torque capacity adaptation involved in the self-learning process in related technologies. If the above self-learning strategy is adopted, then as follows... Figure 5 As shown, when the engine start time is close to the acceptable engine start time T2, due to some occasional factors such as engine coolant temperature and clutch temperature, the start time may be slightly longer or shorter than T2. ​​In this case, according to the self-learning strategy described above, it is still necessary to decrease or increase the clutch torque capacity adaptation amount. This causes the clutch torque capacity adaptation amount ΔM' to be used for the next engine start to change frequently, resulting in unstable start torque and poor robustness of the self-learning strategy. In addition, because the clutch torque capacity adaptation amount ΔM' to be used for the next engine start changes frequently, the data in the storage device used to store ΔM', such as EEPROM, changes frequently, increasing the number of erase and write cycles of the storage device and thus shortening its lifespan.

[0047] Therefore, this disclosure proposes an engine start control method and device for a hybrid electric vehicle. After each engine start is completed, if the start time data of the engine in this start meets a predetermined condition, a first coefficient is calculated based on the start time data. The first coefficient is used to determine whether it is necessary to adjust the clutch torque capacity adaptation amount for the current engine start. The clutch torque capacity adaptation amount is adjusted only if it is determined that the clutch torque capacity adaptation amount needs to be adjusted based on the first coefficient and a predetermined compensation amount.

[0048] Therefore, frequent adjustments to the clutch torque capacity can be avoided, which not only effectively prevents unstable starting torque caused by frequent adjustments to the clutch torque capacity, but also effectively prevents frequent changes in the data in the storage device caused by frequent adjustments to the clutch torque capacity. This not only enhances the robustness of the clutch torque capacity adjustment, but also reduces the number of erase / write cycles of the storage device, thereby extending the life of the storage device.

[0049] To better understand this disclosure, the following is combined with Figure 6 The flowchart shown will be used to explain this in detail.

[0050] Figure 6 This is a flowchart illustrating an engine start-up control method for a hybrid electric vehicle according to an exemplary embodiment. The hybrid electric vehicle can be an HEV or a PHEV, and the powertrain structure of the hybrid electric vehicle can adopt... Figure 1 The structure shown specifically includes an engine, a drive motor, and a clutch disposed between the engine and the drive motor. This control method can be applied to the hybrid control unit (HCU) of the hybrid vehicle. In other words, the HCU can use the control method described in this embodiment to implement engine start control of the hybrid vehicle.

[0051] It should be understandable. Figure 6 This describes the process of self-learning the clutch torque capacity adaptation. This is executed after each engine start-up. Figure 6 The method shown is used to determine the appropriate clutch torque capacity ΔM to be used during the next engine start. For example... Figure 6 As shown, the control method may include the following steps.

[0052] In step S610, after the engine starts, it is determined whether the engine start-up time data meets predetermined conditions. Step S610 corresponds to the first determination step.

[0053] In this embodiment, after the engine starts, startup time data that can characterize whether the clutch torque capacity adaptation used in the engine startup is appropriate can be obtained. The startup time data may include, but is not limited to, the engine startup time in this startup and time data related to the engine startup time in this startup.

[0054] The startup time data meeting the predetermined conditions may include, but is not limited to, the startup time data falling outside the acceptable startup time data range. That is, if the startup time data is greater than the upper limit of the startup time data range, or if the startup time data is less than the lower limit of the startup time data range, the startup time data meets the predetermined conditions. In step S610, it is determined to be "yes", and the following step S620 is executed.

[0055] Conversely, if the startup time data is not less than the lower limit of the startup time data range and not greater than the upper limit of the startup time data range, the startup time data does not meet the predetermined condition, and the determination in step S610 is "no", and the following step S650 is executed.

[0056] It should be understood that the clutch torque capacity adaptation ΔM used during the first start of the engine is 0, that is, the initial value of the clutch torque capacity adaptation is 0. The method of this embodiment can be used to determine the clutch torque capacity adaptation for non-first starts of the engine.

[0057] In step S620, a first coefficient is calculated based on the startup time data. Step S620 corresponds to the first calculation step.

[0058] In this embodiment, any suitable algorithm can be used to calculate a first coefficient to characterize the urgency of self-learning of the clutch torque capacity adaptation for this engine start based on the above-mentioned start time data, so that in the following step S630, it can be determined whether self-learning of the clutch torque capacity adaptation for this engine start is required based on the calculated first coefficient.

[0059] In step S630, it is determined whether the clutch torque capacity adaptation amount for this engine start needs to be adjusted based on the first coefficient. Step S630 corresponds to the second determination step.

[0060] In this embodiment, if the first coefficient calculated in step S620 indicates a high urgency of self-learning of the clutch torque capacity adaptation amount for the current start of the engine, for example, if the first coefficient falls outside the coefficient range, it means that self-learning of the clutch torque capacity adaptation amount for the current start of the engine is required, that is, the clutch torque capacity adaptation amount needs to be adjusted. In other words, if the determination in step S630 is "yes", the following step S640 is executed.

[0061] If the urgency of self-learning of the clutch torque capacity adaptation of the engine for this start is low, as indicated by the first coefficient calculated in step S620 (e.g., the first coefficient falls within the coefficient range), it means that there is no need to perform self-learning of the clutch torque capacity adaptation for the engine for this start, that is, there is no need to adjust the clutch torque capacity adaptation. In other words, the judgment in step S630 is "No", and the following step S650 is executed.

[0062] In step S640, the clutch torque capacity adaptation amount is adjusted according to the first coefficient and the predetermined compensation amount, and the adjusted clutch torque capacity adaptation amount is stored, wherein the adjusted clutch torque capacity adaptation amount is used for the next start of the engine. Step S640 corresponds to the adjustment step.

[0063] In this embodiment, the clutch torque capacity adaptation amount used for the current engine start can be adjusted based on a first coefficient calculated based on the start time data and a predetermined compensation amount during the current engine start, and the adjusted clutch torque capacity adaptation amount can be stored as the clutch torque capacity adaptation amount to be used in the next engine start.

[0064] The predetermined compensation amount can be a preset value, such as a value pre-calibrated by an engineer. For example, the predetermined compensation amount can generally be 3-5 Nm. Of course, it should be understood that the predetermined compensation amount can also be a value calculated by combining engine historical start-up data and using a corresponding algorithm. This embodiment does not specifically limit the setting method and specific value of the predetermined compensation amount. Based on this embodiment, those skilled in the art can adopt any other suitable method and any suitable value as the predetermined compensation amount according to actual application needs.

[0065] In one possible implementation, the clutch torque capacity adaptation amount for the current engine start can be adjusted according to a first coefficient and a predetermined compensation amount by: obtaining a correspondence table between the first coefficient and the adjustment direction (decrease / increase), finding the adjustment direction corresponding to the start time data in the correspondence table, and adjusting the clutch torque capacity adaptation amount for the current engine start according to the found adjustment direction and the predetermined compensation amount.

[0066] In one possible implementation, the clutch torque capacity adaptation amount for the current engine start can also be adjusted according to the first coefficient and the predetermined compensation amount by: obtaining a correspondence table between the first coefficient and the algorithm for adjusting the aforementioned clutch torque capacity adaptation amount; finding the algorithm corresponding to the first coefficient in the correspondence table; calculating the adjustment amount for adjusting the aforementioned clutch torque capacity adaptation amount according to the predetermined compensation amount and using the found algorithm; and using the adjustment amount to adjust the aforementioned clutch torque capacity adaptation amount.

[0067] In step S650, the clutch torque capacity adaptation amount for this engine start is stored.

[0068] In this embodiment, the clutch torque capacity adaptation value used in this startup can still be applied to the next startup. Therefore, there is no need to adjust the clutch torque capacity adaptation value used in this startup. Thus, the clutch torque capacity adaptation value used in this startup can be directly stored as the clutch torque capacity adaptation value to be used in the next startup.

[0069] The hybrid electric vehicle engine start control method of this embodiment calculates a first coefficient based on the start time data after each engine start, provided that the start time data of the engine in this start meets predetermined conditions. Based on the first coefficient, it is determined whether the clutch torque capacity adaptation amount used for this engine start needs to be adjusted. The clutch torque capacity adaptation amount is only adjusted when it is determined that the clutch torque capacity adaptation amount needs to be adjusted based on the first coefficient. This avoids frequent adjustments to the clutch torque capacity adaptation amount, thereby effectively preventing the instability of the start torque caused by frequent adjustments to the clutch torque capacity adaptation amount, and thus enhancing the robustness of the clutch torque capacity adaptation amount adjustment.

[0070] In addition, since frequent adjustments to the clutch torque capacity can be avoided, frequent changes in the data in the storage device caused by frequent adjustments to the clutch torque capacity can be effectively avoided, thereby reducing the number of erase / write cycles of the storage device and extending its lifespan.

[0071] Figure 7 This is a schematic diagram comparing the changes in clutch torque capacity adaptation during the self-learning process of the engine start-up control method after applying this embodiment and related technologies. Figure 7 As shown, compared with the use of the self-learning strategy in the prior art to adjust the clutch torque capacity adaptation amount used in this engine start-up, the use of the self-learning strategy in this embodiment to adjust the clutch torque capacity adaptation amount avoids the fluctuation of the clutch torque capacity adaptation amount, thus improving the robustness of the self-learning strategy.

[0072] In one possible implementation, the start-up time data may include: the start-up time during the current start-up of the engine, from when the torque capacity of the clutch reaches a threshold torque capacity to when the engine speed reaches a threshold speed, wherein if the start-up time is greater than the upper limit of the start-up time or if the start-up time is less than the lower limit of the start-up time, the first determination step determines that the start-up time data meets the predetermined condition.

[0073] In this embodiment, the engine start-up time data during this start-up may include the engine start-up time during this start-up. This start-up time represents the time from when the clutch torque capacity reaches the threshold torque capacity to when the engine speed reaches the threshold speed during this engine start-up period. Accordingly, if the start-up time is greater than the upper limit of the start-up time or less than the lower limit of the start-up time, it is determined as "yes" in step S610; conversely, if the start-up time is not less than the lower limit of the start-up time and not greater than the upper limit of the start-up time, it is determined as "no" in step S610.

[0074] In one possible implementation, step S630 includes: determining whether the first coefficient is greater than the upper limit of the first coefficient or less than the lower limit of the first coefficient; if the first coefficient is greater than the upper limit of the first coefficient or less than the lower limit of the first coefficient, determining that the clutch torque capacity adaptation amount needs to be adjusted.

[0075] In this embodiment, if the first coefficient is greater than the upper limit of the first coefficient or less than the lower limit of the first coefficient, then the first coefficient indicates a high urgency for self-learning of the clutch torque capacity adaptation of the engine in this start-up, requiring self-learning of the clutch torque capacity adaptation of the engine in this start-up, and step S630 determines "yes". Otherwise, if the first coefficient is not less than the lower limit of the first coefficient and not greater than the upper limit of the first coefficient, then the first coefficient indicates a low urgency for self-learning of the clutch torque capacity adaptation of the engine in this start-up, requiring no self-learning of the clutch torque capacity adaptation of the engine in this start-up, and step S630 determines "no".

[0076] In one possible implementation, step S640 may include: determining the torque adjustment direction based on the first coefficient; and adjusting the predetermined compensation amount by the clutch torque capacity adaptation amount according to the torque adjustment direction.

[0077] In this embodiment, if the first coefficient K is greater than the upper limit value Ku of the first coefficient, it indicates that the start-up time is too long and the target clutch torque capacity transmitted by the clutch is too small. Therefore, it is necessary to increase the clutch torque capacity adaptation amount used in this engine start-up. Thus, the torque adjustment direction is determined to be upward, and the clutch torque capacity adaptation amount used in this engine start-up is increased by a predetermined compensation amount, that is, △M'=△M+△M0, where △M' represents the adjusted clutch torque capacity adaptation amount, △M represents the clutch torque capacity adaptation amount used in this engine start-up, △M0 represents the predetermined compensation amount, and Ku represents the upper limit value of the first coefficient, which can be calibrated by the engineer.

[0078] If the first coefficient K is less than the lower limit of the first coefficient Kd, it indicates that the starting time is too short and the target clutch torque capacity transmitted by the clutch is too large. Therefore, it is necessary to reduce the clutch torque capacity adaptation used in this engine start. Thus, the torque adjustment direction is determined to be downward, and the clutch torque capacity adaptation used in this engine start is reduced by a predetermined compensation amount, that is, △M'=△M-△M0, where △M' represents the adjusted clutch torque capacity adaptation, △M represents the clutch torque capacity adaptation used in this engine start, △M0 represents the predetermined compensation amount, and Kd represents the lower limit of the first coefficient, which can be calibrated by the engineer.

[0079] It should be noted that after adjusting the clutch torque capacity adaptation amount, the first coefficient K needs to be initialized to 0. That is, in each engine start, the first coefficient K is only calculated when it is determined in step S610 that the first coefficient K needs to be calculated (i.e., the start time data in this start meets the predetermined conditions), and the initial value of the first coefficient K is 0.

[0080] In one possible implementation, step S620 may include: calculating the first coefficient based on the start-up time data and an acceptable engine start-up time, wherein the start-up time data includes: the start-up time during the current engine start-up period from when the torque capacity of the clutch reaches a threshold torque capacity until the engine speed reaches a threshold speed.

[0081] In this embodiment, the first coefficient can be calculated based on the above-mentioned start-up time data and the acceptable engine start-up time, using a relevant algorithm.

[0082] In one possible implementation, the first coefficient K can be calculated using the formula K = K' + Gu + Gd. If the engine starts for too long in this start-up (e.g., the start-up time is greater than the upper limit of the start-up time), Gu can be calculated using the formula Gu = Rond((T3 – (T2 + Δt2)) / t0); if the engine starts for too short in this start-up (e.g., the start-up time is less than the lower limit of the start-up time), Gd can be calculated using the formula Gd = Rond((T1 – (T2 – Δt1)) / t0).

[0083] Where K' is the first coefficient K at the previous moment, T2 is the acceptable engine start time, T2+△t2 represents the upper limit of the start time, T3 is the start time of the current engine start, t0 is the time unit, T2-△t1 represents the lower limit of the start time, T1 is the start time of the current engine start, Rond() is the floor function, Gu is a positive integer, and Gd is a negative integer.

[0084] The following description serves as a specific example of the self-learning strategy in this embodiment.

[0085] Calculate the intermediate variables Gu and Gd. Specifically, if the engine's start-up time in this start-up is greater than the upper limit of the start-up time, then Gu is calculated using the formula Gu = Rond((T3 – (T2 + Δt2)) / t0); if the engine's start-up time in this start-up is less than the lower limit of the start-up time, then Gd is calculated using the formula Gd = Rond((T1 – (T2 - Δt1)) / t0).

[0086] If the self-learning process is activated, that is, if the engine's start-up time in this start-up is greater than the upper limit of the start-up time or less than the lower limit of the start-up time, then the first coefficient K is calculated using the formula K = K' + Gu + Gd.

[0087] If the first coefficient K > the upper limit of the first coefficient Ku, then the adjusted clutch torque capacity adaptation amount is calculated and stored using the formula △M' = △M + △M0, and the first coefficient K is reset to zero. If the first coefficient K < the lower limit of the first coefficient Kd, then the adjusted clutch torque capacity adaptation amount is calculated and stored using the formula △M' = △M - △M0, and the first coefficient K is reset to zero. If the lower limit of the first coefficient Kd ≤ the first coefficient K ≤ the upper limit of the first coefficient Ku, then the clutch torque capacity adaptation amount is not adjusted and the first coefficient K remains unchanged.

[0088] Therefore, intermediate variables Gu and Gd, calculated based on the engine's start-up time data and acceptable start-up time data, are introduced to characterize the urgency of self-learning required for this start-up. The clutch torque capacity adaptation for this engine start-up is adjusted only when the cumulative urgency K for self-learning reaches the upper limit Ku or the lower limit Kd. Specifically, as follows... Figure 7 As shown, compared to the frequent fluctuations in the curve of clutch torque capacity adaptation ΔM in the prior art, the curve of clutch torque capacity adaptation ΔM in this embodiment does not fluctuate.

[0089] In one possible implementation, the above engine start control method further includes:

[0090] Calculate the target clutch torque capacity when fuel is first supplied to the engine, based on the basic clutch torque capacity and the adjusted clutch torque capacity adaptation.

[0091] During the next start-up of the engine, fuel is supplied to the engine when the torque capacity of the clutch reaches the target clutch torque capacity and the engine speed reaches a predetermined speed.

[0092] In this embodiment, a basic clutch torque capacity is introduced when calculating the target clutch torque capacity when supplying fuel to the engine. The target clutch torque capacity when fuel supply to the engine begins at the next engine start can be calculated using appropriate algorithms, including but not limited to addition, based on the basic clutch torque capacity and the adjusted clutch torque capacity adaptation.

[0093] In one possible implementation, the basic torque capacity of the clutch can be determined based on the engine's resistance torque. Specifically, the basic torque capacity of the clutch can be determined by: obtaining relevant information affecting the engine's resistance torque, including the engine's coolant temperature; determining the engine's resistance torque based on this relevant information; and determining the basic torque capacity of the clutch based on the determined resistance torque.

[0094] Since information including, but not limited to, engine coolant temperature affects the engine's drag torque—for example, the lower the coolant temperature, the greater the engine's drag torque—the engine's drag torque can be determined based on this information, and then the basic clutch torque capacity can be determined based on the determined drag torque. In one possible implementation, a coolant temperature sensor can be used to detect the coolant temperature, and the coolant temperature detected by the sensor can be acquired.

[0095] During the next engine start-up, it is possible to monitor whether the clutch torque capacity has decreased to the calculated target clutch torque capacity and whether the engine speed has reached a threshold speed; when it is detected that the clutch torque capacity has decreased to the target clutch torque capacity and the engine speed has reached the threshold speed, for example, a command to start supplying fuel to the engine is sent to the fuel feeding device including the fuel tank and the injector; in response to receiving the command, the fuel feeding device begins to supply fuel to the engine.

[0096] The hybrid vehicle engine start control method of this embodiment, after each engine start, calculates a first coefficient based on the start time data if the start time data of the engine in this start meets predetermined conditions. Based on the first coefficient, it determines whether the clutch torque capacity adaptation amount used for this engine start needs adjustment. The clutch torque capacity adaptation amount is adjusted only if it is determined that adjustment is needed based on the first coefficient, and the adjusted clutch torque capacity adaptation amount is stored. During the next engine start, a target clutch torque capacity is calculated based on the basic clutch torque capacity and the stored clutch torque capacity adaptation amount. When the clutch torque capacity reaches the calculated target clutch torque capacity and the engine speed reaches a threshold speed, fuel is supplied to the engine. Since the target clutch torque capacity used is calculated based on the adjusted clutch torque capacity adaptation amount, the target clutch torque capacity used in the next engine start is always reasonable, ensuring that the engine speed reaches the threshold speed in a timely manner during the next engine start, thereby enabling timely engine start processing.

[0097] Figure 8 This is a block diagram illustrating an engine start control device for a hybrid electric vehicle according to an exemplary embodiment. The hybrid electric vehicle can be an HEV or a PHEV, and the powertrain structure of the hybrid electric vehicle can adopt... Figure 1 The structure shown specifically includes an engine, a drive motor, and a clutch disposed between the engine and the drive motor. This control device 800 can be applied to the hybrid power control unit (HCU) of the hybrid vehicle. Figure 8 As shown, the control device 800 may include a first judgment module 810, a first calculation module 820, a second judgment module 830, and an adjustment module 840.

[0098] The first judgment module 810 is used to determine whether the start-up time data of the engine in this start-up meets a predetermined condition after the engine has been started. The first calculation module 820 is connected to the first judgment module 810 and is used to calculate a first coefficient based on the start-up time data if the first judgment module 810 determines that the start-up time data meets the predetermined condition.

[0099] The second judgment module 830 is connected to the first calculation module 820 and is used to determine whether the clutch torque capacity adaptation amount for the current engine start needs to be adjusted based on the first coefficient. The adjustment module 840 is connected to the second judgment module 830 and is used to adjust the clutch torque capacity adaptation amount based on the first coefficient and a predetermined compensation amount if the second judgment module 830 determines that the clutch torque capacity adaptation amount needs to be adjusted, and to store the adjusted clutch torque capacity adaptation amount, wherein the adjusted clutch torque capacity adaptation amount is used for the next engine start.

[0100] In one possible implementation, the start-up time data includes: the start-up time during the current start-up of the engine, from when the torque capacity of the clutch reaches a threshold torque capacity to when the engine speed reaches a threshold speed, wherein if the start-up time is greater than the upper limit of the start-up time or less than the lower limit of the start-up time, the first judgment module 810 determines that the start-up time data meets the predetermined condition.

[0101] In one possible implementation, the second judgment module 830 is configured to: determine whether the first coefficient is greater than the upper limit of the first coefficient or less than the lower limit of the first coefficient; if the first coefficient is greater than the upper limit of the first coefficient or less than the lower limit of the first coefficient, determine that the clutch torque capacity adaptation amount needs to be adjusted.

[0102] In one possible implementation, the adjustment module 840 is configured to: determine the torque adjustment direction based on the first coefficient; and adjust the predetermined compensation amount by the clutch torque capacity adaptation amount according to the torque adjustment direction.

[0103] In one possible implementation, the adjustment module 840 is configured to: if the first coefficient is greater than the upper limit of the first coefficient, determine that the torque adjustment direction is upward, and increase the clutch torque capacity adaptation amount by the predetermined compensation amount; if the first coefficient is less than the lower limit of the first coefficient, determine that the torque adjustment direction is downward, and decrease the clutch torque capacity adaptation amount by the predetermined compensation amount.

[0104] In one possible implementation, the first adjustment module 820 is configured to calculate the first coefficient based on the start-up time data and an acceptable engine start-up time, wherein the start-up time data includes the start-up time during the current engine start-up period, from when the clutch torque capacity reaches a threshold torque capacity until the engine speed reaches a threshold speed.

[0105] In one possible implementation, the control device 800 may further include:

[0106] The second calculation module (not shown) is used to calculate the target clutch torque capacity when fuel is supplied to the engine, based on the basic clutch torque capacity and the adjusted clutch torque capacity adaptation.

[0107] A starting module (not shown) is used to begin supplying fuel to the engine during the next start-up of the engine, when the torque capacity of the clutch reaches the target clutch torque capacity and the engine speed reaches a predetermined speed.

[0108] Regarding the apparatus in the above embodiments, the specific manner in which each module performs its operation has been described in detail in the embodiments related to the method, and will not be elaborated upon here.

[0109] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, and are not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical applications, or technical improvements to the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for controlling the engine start of a hybrid electric vehicle, the hybrid electric vehicle comprising an engine, a drive motor, and a clutch disposed between the engine and the drive motor, characterized in that, The engine start control method includes: The first judgment step is used to determine whether the start-up time data of the engine in this start-up meets the predetermined conditions after the engine is started. The first calculation step is used to calculate a first coefficient based on the startup time data if it is determined that the startup time data meets the predetermined conditions. The second judgment step is used to determine, based on the first coefficient, whether it is necessary to adjust the clutch torque capacity adaptation amount for this engine start-up; and The adjustment step is used to adjust the clutch torque capacity adaptation amount according to the first coefficient and the predetermined compensation amount if it is determined that the clutch torque capacity adaptation amount needs to be adjusted, and to store the adjusted clutch torque capacity adaptation amount, wherein the adjusted clutch torque capacity adaptation amount is used for the next start of the engine.

2. The engine start control method according to claim 1, characterized in that, The start-up time data includes: the start-up time during the current engine start-up period, from when the clutch torque capacity reaches the threshold torque capacity until the engine speed reaches the threshold speed. Specifically, if the startup time is greater than the upper limit of the startup time or less than the lower limit of the startup time, the first determination step determines that the startup time data meets the predetermined condition.

3. The engine start control method according to claim 1, characterized in that, The second determination step includes: Determine whether the first coefficient is greater than the upper limit of the first coefficient or less than the lower limit of the first coefficient; If the first coefficient is greater than the upper limit of the first coefficient or less than the lower limit of the first coefficient, it is determined that the clutch torque capacity adaptation amount needs to be adjusted.

4. The engine start control method according to claim 3, characterized in that, The adjustment steps include: The torque adjustment direction is determined based on the first coefficient; According to the torque adjustment direction, the predetermined compensation amount is adjusted by the clutch torque capacity adaptation amount.

5. The engine start control method according to claim 4, characterized in that, The adjustment steps include: If the first coefficient is greater than the upper limit of the first coefficient, then the torque adjustment direction is determined to be upward, and the clutch torque capacity adaptation amount is increased by the predetermined compensation amount. If the first coefficient is less than the lower limit of the first coefficient, then the torque adjustment direction is determined to be downward, and the clutch torque capacity adaptation amount is reduced by the predetermined compensation amount.

6. The engine start control method according to claim 1, characterized in that, The calculation steps include: The first coefficient is calculated based on the start-up time data and the acceptable engine start-up time, wherein the start-up time data includes: the start-up time during the current engine start-up period, from when the clutch torque capacity reaches the threshold torque capacity to when the engine speed reaches the threshold speed.

7. The engine starting control method according to any one of claims 1 to 6, characterized in that, The adjustment steps are followed by: The second calculation step is used to calculate the target clutch torque capacity when fuel is supplied to the engine, based on the basic clutch torque capacity and the adjusted clutch torque capacity adaptation. A start-up step is used to begin supplying fuel to the engine during the next start-up of the engine, when the torque capacity of the clutch reaches the target clutch torque capacity and the engine speed reaches a predetermined speed.

8. An engine start control device for a hybrid electric vehicle, the hybrid electric vehicle comprising an engine, a drive motor, and a clutch disposed between the engine and the drive motor, characterized in that, The engine start control device includes: The first judgment module is used to determine whether the start-up time data of the engine in this start-up meets the predetermined conditions after the engine is started. The first calculation module is used to calculate a first coefficient based on the startup time data if it is determined that the startup time data meets the predetermined conditions. The second judgment module is used to determine, based on the first coefficient, whether it is necessary to adjust the clutch torque capacity adaptation amount for this engine start; and An adjustment module is used to adjust the clutch torque capacity adaptation amount according to the first coefficient and a predetermined compensation amount if it is determined that the clutch torque capacity adaptation amount needs to be adjusted, and to store the adjusted clutch torque capacity adaptation amount, wherein the adjusted clutch torque capacity adaptation amount is used for the next start of the engine.

9. The engine start control device according to claim 8, characterized in that, The start-up time data includes: the start-up time during the current engine start-up period, from when the clutch torque capacity reaches the threshold torque capacity until the engine speed reaches the threshold speed. Specifically, if the startup time is greater than the upper limit of the startup time or less than the lower limit of the startup time, the first judgment module determines that the startup time data meets the predetermined condition.

10. The engine start control device according to claim 8, characterized in that, The second judgment module is configured as follows: Determine whether the first coefficient is greater than the upper limit of the first coefficient or less than the lower limit of the first coefficient; If the first coefficient is greater than the upper limit of the first coefficient or less than the lower limit of the first coefficient, it is determined that the clutch torque capacity adaptation amount needs to be adjusted.

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