Hybrid vehicle parallel start control method, system and hybrid vehicle

Abstract

The application discloses a hybrid vehicle parallel starting control method, a system and a hybrid vehicle. The hybrid vehicle parallel starting control method comprises the following steps: acquiring the current working conditions of a clutch and a gearbox of the hybrid vehicle, an engine request torque of the hybrid vehicle and a starting mode of the hybrid vehicle; judging whether the hybrid vehicle meets an overheat protection condition according to the current working conditions of the clutch and the gearbox, determining a starting basic torque according to a judgment result and the engine request torque; determining a starting clutch request torque based on the starting basic torque according to the starting mode of the hybrid vehicle; and performing starting control on the clutch according to the starting clutch request torque. The application can improve the starting safety, responsiveness and power performance of the hybrid vehicle.

Description

Technical Field

[0001] This invention relates to the field of vehicle control technology, and in particular to a method, system, and hybrid vehicle for parallel start control. Background Technology

[0002] With the development of electrification systems and increasingly stringent national regulations on fuel consumption and emissions, hybrid technology has become crucial for achieving energy conservation and emission reduction. Existing technologies include dual-motor hybrid systems, which have three modes: pure electric mode, series mode, and parallel mode. For example... Figure 1 As shown, in series mode, the dual-motor hybrid system drives the wheels through motor P2 and clutch C0 is not engaged. The engine charges the battery through motor P1 and motor P2 drives the wheels. In parallel mode, clutch C0 is engaged and the engine directly drives the wheels.

[0003] Poor start-up control in hybrid vehicles not only affects system responsiveness but can also lead to engine stalling due to improper clutch torque control, and hardware damage due to neglecting clutch and transmission fluid temperatures. Therefore, a proper start-up control method is crucial for hybrid vehicles. Summary of the Invention

[0004] In view of the above problems, the present invention provides a method, system and hybrid vehicle for parallel start control of hybrid vehicles that overcomes or at least partially solves the above problems.

[0005] One object of the present invention is to improve the starting safety of hybrid vehicles.

[0006] A further object of the present invention is how to control the clutch torque to avoid engine stalling due to improper clutch torque control.

[0007] Another further object of the present invention is to control the clutch torque to improve responsiveness, power and safety during start-up.

[0008] Another further objective of the present invention is to control engine torque to prevent engine stalling and to further improve responsiveness, power and safety during start-up.

[0009] In particular, the present invention provides a parallel start control method for hybrid vehicles, comprising the following steps:

[0010] The current operating conditions of the clutch and transmission of the hybrid vehicle, the engine torque requested by the hybrid vehicle, and the starting method of the hybrid vehicle are obtained.

[0011] Based on the current operating conditions of the clutch and the transmission, a judgment is made as to whether the hybrid vehicle meets the overheat protection conditions, and the starting basic torque is determined based on the judgment result and the engine requested torque.

[0012] The starting clutch request torque is determined based on the starting base torque according to the starting method of the hybrid vehicle;

[0013] The clutch is started by controlling the clutch according to the torque requested by the starting clutch.

[0014] Further, the step of determining whether the hybrid vehicle meets the overheat protection conditions based on the current operating conditions of the clutch and the transmission, and determining the starting basic torque based on the determination result and the engine requested torque, includes:

[0015] When the clutch is not fully engaged and the transmission is in gear, determine whether the hybrid vehicle meets the overheat protection conditions.

[0016] When it is determined that the hybrid vehicle meets the overheat protection conditions, the engine requested torque is subtracted from the preset overheat protection offset torque to obtain the starting basic torque.

[0017] Furthermore, when the hybrid vehicle starts using an accelerator pedal-assisted start method, the step of determining the starting clutch request torque based on the starting fundamental torque according to the starting method of the hybrid vehicle includes:

[0018] The starting basic torque is limited by upper and lower limits to obtain the first starting limit torque;

[0019] The first pre-engagement torque is obtained by adding the first start-up limiting torque to the start-up pre-engagement torque and the start-up clutch compensation torque of the hybrid vehicle.

[0020] When the brake pedal of the hybrid vehicle is depressed, the brake clutch request torque when the brake pedal is depressed is determined based on the magnitude of the brake force at the crankshaft end of the hybrid vehicle and the first pre-requested clutch torque.

[0021] The smaller of the first pre-requested clutch torque and the brake clutch requested torque is taken to obtain the first requested clutch torque;

[0022] When the engine speed of the hybrid vehicle is less than the target idle speed, the anti-stalling clutch torque is determined by looking up a table based on the rate of change of the engine speed and the difference between the engine speed and the target idle speed.

[0023] The starting clutch request torque is obtained by taking the smaller of the first requested clutch torque and the anti-stalling clutch torque.

[0024] Furthermore, the step of determining the starting clutch request torque based on the starting basic torque according to the starting mode of the hybrid vehicle further includes:

[0025] When the brake pedal of the hybrid vehicle is not depressed and the engine speed is greater than or equal to the target idle speed, the first pre-requested clutch torque is used as the start-up clutch request torque.

[0026] When the brake pedal of the hybrid vehicle is not depressed and the engine speed is less than the target idle speed, the starting clutch request torque is obtained by taking the smaller of the first pre-requested clutch torque and the anti-stalling clutch torque.

[0027] When the brake pedal of the hybrid vehicle is depressed and the engine speed is greater than or equal to the target idle speed, the first requested clutch torque is used as the starting clutch requested torque.

[0028] Furthermore, when the hybrid vehicle's starting method is a coasting start, the step of determining the starting clutch request torque based on the starting basic torque according to the hybrid vehicle's starting method includes:

[0029] The larger value between the basic starting torque and zero is taken, and then the larger value is subject to upper and lower limits to obtain the second starting limit torque.

[0030] When the brake pedal of the hybrid vehicle is depressed, the smaller of the second start-up limiting torque and the brake clutch request torque is taken to obtain the second requested clutch torque.

[0031] When the engine speed of the hybrid vehicle is less than the target idle speed, the anti-stalling clutch torque is determined by looking up a table based on the rate of change of the engine speed and the difference between the engine speed and the target idle speed.

[0032] The starting clutch request torque is obtained by taking the smaller value between the second requested clutch torque and the anti-stalling clutch torque.

[0033] Furthermore, the step of determining the starting clutch request torque based on the starting basic torque according to the starting mode of the hybrid vehicle further includes:

[0034] When the brake pedal of the hybrid vehicle is not depressed and the engine speed is greater than or equal to the target idle speed, the second start-up limiting torque is used as the start-up clutch request torque.

[0035] When the brake pedal of the hybrid vehicle is not depressed and the engine speed is less than the target idle speed, the starting clutch request torque is obtained by taking the smaller of the second start-up limiting torque and the anti-stalling clutch torque.

[0036] When the brake pedal of the hybrid vehicle is depressed and the engine speed is greater than or equal to the target idle speed, the second requested clutch torque is used as the starting clutch requested torque.

[0037] Furthermore, when the hybrid vehicle's starting method is a launch start, the step of determining the starting clutch request torque based on the starting basic torque according to the hybrid vehicle's starting method includes:

[0038] The second pre-requested clutch torque is obtained by adding the starting base torque to the starting pre-engagement torque and the starting clutch compensation torque of the hybrid vehicle.

[0039] When the engine speed of the hybrid vehicle is less than the target idle speed, the anti-stalling clutch torque is determined by looking up a table based on the rate of change of the engine speed and the difference between the engine speed and the target idle speed.

[0040] The starting clutch request torque is obtained by taking the smaller of the second pre-requested clutch torque and the anti-stalling clutch torque.

[0041] When the engine speed of the hybrid vehicle is greater than or equal to the target idle speed, the second pre-requested clutch torque is used as the start-up clutch request torque.

[0042] Furthermore, the starting clutch compensation torque is obtained in the following manner:

[0043] Based on the starting method of the hybrid vehicle, a target speed calculation method corresponding to the starting method is selected from a plurality of preset target speed calculation methods, and the target engine speed for the next cycle is calculated using the target speed calculation method.

[0044] The target engine speed is limited by upper and lower limits to obtain the target engine speed limit.

[0045] Subtract the actual engine speed from the target engine speed limit to obtain the target engine speed difference;

[0046] Query the target P-term coefficient corresponding to the target engine speed difference from the second preset mapping table that stores the relationship between engine speed difference and P-term coefficient;

[0047] Multiply the target P-term coefficient by the target engine speed difference, and then multiply by the preset engine rotational inertia to obtain the P-term torque;

[0048] The starting clutch compensation torque is obtained by taking the negative of the torque term P.

[0049] Further, the step of selecting a target speed calculation method corresponding to the starting mode from a preset plurality of target speed calculation methods based on the starting mode of the hybrid vehicle, and using the target speed calculation method to calculate the target engine speed for the next cycle includes: when the starting mode of the hybrid vehicle is a throttle start mode or a launch start mode, selecting a first target speed calculation method to calculate the target engine speed, the first target speed calculation method including the following steps:

[0050] The sum of the torques of the engine and the electric motor of the hybrid vehicle is obtained to get the overall torque;

[0051] The smaller of the overall torque and the engine-requested torque is taken to obtain the target smaller torque.

[0052] Obtain the temperatures of the clutch and the gearbox;

[0053] When the temperature of the clutch is less than 185°C and the temperature of the gearbox is less than 100°C, the target engine speed corresponding to the target minimum torque and the current engine requested torque is queried from a first preset relationship table that stores the relationship between minimum torque, engine requested torque and engine speed.

[0054] When the temperature of the clutch is greater than 200°C and the temperature of the gearbox is greater than 110°C, the target engine speed corresponding to the target minimum torque and the current engine requested torque is queried from a second preset relationship table that stores the relationship between the minimum torque, the engine requested torque and the engine speed. The second preset relationship table is different from the first preset relationship table.

[0055] Further, the step of selecting a target speed calculation method corresponding to the starting mode from a preset plurality of target speed calculation methods based on the starting mode of the hybrid vehicle, and using the target speed calculation method to calculate the target engine speed for the next cycle includes: when the starting mode of the hybrid vehicle is a neutral coasting start mode, selecting a second target speed calculation method to calculate the target engine speed, the second target speed calculation method including the following steps:

[0056] Obtain the starting acceleration of the hybrid vehicle at start-up;

[0057] The starting acceleration is compared with the preset acceleration;

[0058] When the starting acceleration is less than the preset acceleration, the target engine speed for the next cycle corresponding to the current engine speed is queried from a third preset relationship table that stores the relationship between the current engine speed and the engine speed of the next cycle.

[0059] When the starting acceleration is greater than or equal to the preset acceleration, the target engine speed for the next cycle corresponding to the current engine speed is queried from the fourth preset relationship table, which stores the relationship between the current engine speed and the target engine speed for the next cycle. The fourth preset relationship table is different from the third preset relationship table.

[0060] Further, the step of determining whether the hybrid vehicle meets the overheat protection conditions based on the current operating conditions of the clutch and the transmission, and determining the starting basic torque based on the determination result and the engine requested torque; and determining the starting clutch requested torque based on the starting basic torque according to the starting mode of the hybrid vehicle, includes:

[0061] When the clutch is in a fully engaged state, determine whether the hybrid vehicle meets the overheat protection conditions.

[0062] When it is determined that the hybrid vehicle meets the overheat protection conditions, the engine requested torque is subtracted from the preset overheat protection offset torque to obtain the starting basic torque, and the starting basic torque is used as the starting clutch requested torque.

[0063] When the hybrid vehicle does not meet the overheat protection conditions, the engine requested torque is used as the starting clutch requested torque.

[0064] Furthermore, the overheat protection condition is determined to be satisfied when the following conditions are met simultaneously:

[0065] The temperature of the clutch is greater than or equal to 220°C, and the temperature of the gearbox is greater than or equal to 120°C.

[0066] The hybrid vehicle can start either by pressing the accelerator or by launching.

[0067] When the brake pedal of the hybrid vehicle is depressed, the rate of change of the engine's requested torque is less than a first preset rate of change; when the brake pedal is not depressed, the rate of change of the engine's requested torque is less than a second preset rate of change; and the first preset rate of change is less than the second preset rate of change.

[0068] The difference between the maximum engine torque limit corresponding to the current engine speed and the requested engine torque of the hybrid vehicle is greater than the preset torque value.

[0069] The current speed of the hybrid vehicle is less than or equal to the preset speed.

[0070] Furthermore, the parallel start control method for hybrid vehicles also includes the following steps:

[0071] When the clutch is not fully engaged and the transmission is in off-gear mode, the starting clutch is determined to have a torque of zero.

[0072] Furthermore, the parallel start control method for hybrid vehicles also includes the following steps:

[0073] When the clutch is fully engaged, or when the clutch is not fully engaged and the transmission is in off-gear mode, the engine compensation torque is determined to be zero.

[0074] When the clutch is not fully engaged and the gearbox is in gear, the engine compensation torque is calculated using the engine compensation torque calculation method.

[0075] The engine target torque is obtained by adding the engine requested torque to the engine compensated torque;

[0076] When the brake pedal of the hybrid vehicle is depressed, the target torque of the engine is limited to obtain the starting engine request torque.

[0077] The engine is controlled to start based on the requested torque from the starting engine.

[0078] Furthermore, the engine compensation torque calculation method includes the following steps:

[0079] When the hybrid vehicle meets the overheat protection condition, the starting pre-engagement torque of the hybrid vehicle is added to the starting engine compensation torque, and then the preset overheat protection offset torque is added to obtain the engine compensation torque, wherein the starting engine compensation torque is equal to the P-term torque of the hybrid vehicle.

[0080] When the hybrid vehicle does not meet the overheat protection conditions, the starting pre-engagement torque is added to the starting engine compensation torque to obtain the engine compensation torque.

[0081] Furthermore, in the step of limiting the engine target torque to obtain the starting engine request torque when the brake pedal of the hybrid vehicle is depressed, the method for limiting the engine target torque is as follows:

[0082] When the brake pedal of the hybrid vehicle is depressed, determine the brake clutch request torque when the brake pedal is depressed.

[0083] The starting engine requested torque is obtained by taking the smaller of the engine target torque and the braking engine requested torque.

[0084] Furthermore, the initial engagement torque is determined in the following manner:

[0085] Obtain the current speed of the hybrid vehicle;

[0086] The system queries a first preset mapping table that stores the relationship between vehicle speed and pre-engagement torque to determine the pre-engagement torque corresponding to the current vehicle speed.

[0087] In particular, the present invention also provides a parallel start control system for a hybrid vehicle, including a control device, the control device including a memory and a processor, the memory storing a control program, the control program being executed by the processor to implement the aforementioned parallel start control method for a hybrid vehicle.

[0088] In particular, the present invention also provides a hybrid vehicle including the aforementioned hybrid vehicle parallel start control system.

[0089] According to the present invention, the current operating conditions of the clutch and transmission are used to determine whether the hybrid vehicle meets the overheat protection conditions. Then, the starting basic torque is determined based on the judgment result and the engine request torque. Then, the starting clutch request torque is determined based on the starting basic torque according to the starting mode of the hybrid vehicle. Thus, the overheat protection torque is considered in the process of starting control of the clutch, and there will be different starting clutch request torques in different starting modes, thereby improving the starting safety of the hybrid vehicle.

[0090] Furthermore, by setting multiple start control modes during the start-up process, specifically neutral coasting start, launch start, and accelerator start, overheating and braking conditions are handled in each start mode. At the same time, an anti-stalling protection function is added, thereby increasing the system's power and safety, and improving start response.

[0091] Furthermore, by controlling the engine torque, engine stalling can be further prevented, and the responsiveness, power, and safety during start-up can be further improved.

[0092] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below.

[0093] The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0094] The following sections will describe some specific embodiments of the invention in detail by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or portions. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:

[0095] Figure 1 A schematic structural diagram of a dual-motor hybrid power system in the prior art is shown;

[0096] Figure 2 A schematic flowchart of a parallel start control method for a hybrid vehicle according to an embodiment of the present invention is shown;

[0097] Figure 3 A schematic flowchart of a method for determining the starting clutch request torque under the accelerator pedal starting mode according to Embodiment 1 of the present invention is shown;

[0098] Figure 4 A schematic flowchart of a method for obtaining the starting clutch compensation torque according to Embodiment 1 of the present invention is shown;

[0099] Figure 5 A schematic flowchart of a first target rotational speed calculation method according to Embodiment 1 of the present invention is shown;

[0100] Figure 6 A schematic flowchart of a second target rotational speed calculation method according to Embodiment 1 of the present invention is shown;

[0101] Figure 7 A schematic flowchart of a method for determining the starting clutch request torque in a coasting start mode according to Embodiment 1 of the present invention is shown.

[0102] Figure 8 A schematic flowchart of a method for determining the starting clutch request torque in a launch start mode according to Embodiment 1 of the present invention is shown;

[0103] Figure 9 A schematic flowchart illustrating the engine start-up control in the parallel start-up control method for hybrid vehicles according to Embodiment 2 of the present invention is shown.

[0104] Figure 10 A schematic flowchart of the method for calculating engine compensation torque according to Embodiment 2 of the present invention is shown. Detailed Implementation

[0105] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0106] Figure 2 A schematic flowchart of a parallel start control method for a hybrid vehicle according to an embodiment of the present invention is shown. Figure 2 As shown, the parallel start control method for hybrid vehicles includes the following steps:

[0107] Step S100: Obtain the current operating conditions of the clutch and transmission of the hybrid vehicle, the engine torque requested by the hybrid vehicle, and the starting method of the hybrid vehicle.

[0108] Step S200: Based on the current operating conditions of the clutch and transmission, determine whether the hybrid vehicle meets the overheat protection conditions, and determine the starting basic torque based on the judgment result and the engine requested torque.

[0109] Step S300: Determine the starting clutch request torque based on the starting base torque according to the starting method of the hybrid vehicle;

[0110] Step S400: Perform start-up control on the clutch based on the torque requested by the start-up clutch.

[0111] According to the present invention, the current operating conditions of the clutch and transmission are used to determine whether the hybrid vehicle meets the overheat protection conditions. Then, the starting basic torque is determined based on the judgment result and the engine request torque. Then, the starting clutch request torque is determined based on the starting basic torque according to the starting mode of the hybrid vehicle. Thus, the overheat protection torque is considered in the process of starting control of the clutch, and there will be different starting clutch request torques in different starting modes, thereby improving the starting safety of the hybrid vehicle.

[0112] Embodiments of the present invention also provide a parallel start control system for a hybrid vehicle, including a control device. The control device includes a memory and a processor. The memory stores a control program, which, when executed by the processor, is used to implement the aforementioned parallel start control method for a hybrid vehicle.

[0113] Embodiments of the present invention also provide a hybrid vehicle, including the aforementioned hybrid vehicle parallel start control system.

[0114] The following detailed description uses specific examples:

[0115] Example 1:

[0116] In step S100, the clutch includes fully engaged, partially engaged, and disengaged states. The transmission includes both engaged and disengaged states. The hybrid vehicle's starting methods include accelerator-assisted start, coasting start, and launch start. The entry conditions for each starting method are as follows:

[0117] 1) The conditions for entering this accelerator-based start method are that the transmission is in gear and the driver presses the accelerator instead of launching. The condition for exiting is to shift to neutral.

[0118] 2) The conditions for entering the coasting start mode in neutral are that the transmission is in gear, the driver does not press the accelerator to start, the target speed for starting without pressing the accelerator is greater than the target idle speed, and it is a non-launch start.

[0119] 3) The conditions for entering this launch start mode are: throttle opening > 90%, braking torque > 4000 Nm, and vehicle speed < 1 km / h.

[0120] In practice, the clutch can be locked after the vehicle starts under certain conditions to improve torque transmission efficiency. The conditions are as follows:

[0121] 1) The input shaft speed of the gearbox is greater than 900 rpm;

[0122] 2) The absolute value of the difference between the target starting speed and the gearbox input shaft speed is less than the limit of 40 rpm. The calculation method for the target starting speed is described in detail below.

[0123] The following describes the calculation method for the starting clutch requested torque according to the clutch operating condition and the transmission operating condition.

[0124] 1. The clutch is not fully engaged and the transmission is in gear.

[0125] Under this operating condition, step S200 includes: when it is determined that the hybrid vehicle meets the overheat protection conditions, subtracting a preset overheat protection offset torque from the engine request torque to obtain the aforementioned starting basic torque; when it is determined that the hybrid vehicle does not meet the overheat protection conditions, using the engine request torque as the starting basic torque. The overheat protection offset torque can be set to, for example, 50 Nm.

[0126] The overheat protection condition is determined to be met when all of the following conditions are met:

[0127] 1) The temperature of the clutch is greater than or equal to 220℃, and the temperature of the gearbox is greater than or equal to 120℃;

[0128] 2) Hybrid vehicles can start by pressing the accelerator or by launching.

[0129] 3) When the brake pedal of the hybrid vehicle is depressed, the rate of change of the engine requested torque is less than a first preset rate of change, and when the brake pedal is not depressed, the rate of change of the engine requested torque is less than a second preset rate of change. The first preset rate of change is less than the second preset rate of change. For example, the first preset rate of change is 10 Nm / s and the second preset rate of change is 100 Nm / m.

[0130] 4) For hybrid vehicles, the difference between the maximum engine torque limit at the current engine speed and the requested engine torque is greater than the preset torque value. This maximum torque limit is the engine's maximum torque, determined through a universal characteristic diagram obtained from engine bench testing. It is speed-dependent, with different maximum torque limits between 1500 and 5500 RPM. Furthermore, the requested engine torque is the engine torque requested at the corresponding engine speed. This preset torque value could be, for example, 30 Nm.

[0131] 5) The current speed of the hybrid vehicle is less than or equal to the preset speed, which may be, for example, 3 km / h.

[0132] The specific execution steps in step S300 are determined below based on the starting method of the hybrid vehicle.

[0133] 1. Hybrid vehicles start by pressing the accelerator pedal.

[0134] In this starting method, such as Figure 3 As shown, step S300 includes:

[0135] Step S31: Limit the starting basic torque to upper and lower limits to obtain the first starting limit torque;

[0136] Step S32: Add the first start-up limiting torque to the start-up pre-engagement torque of the hybrid vehicle and the start-up clutch compensation torque to obtain the first pre-requested clutch torque.

[0137] Step S33: Determine whether the brake pedal of the hybrid vehicle is pressed. If it is pressed, proceed with steps S34 to S38 in sequence; otherwise, proceed with step S39.

[0138] Step S34: Determine the brake clutch request torque when the brake pedal is depressed based on the magnitude of the crankshaft end braking force of the hybrid vehicle and the torque of the first pre-requested clutch.

[0139] Step S35: Take the smaller of the first pre-requested clutch torque and the brake clutch request torque to obtain the first requested clutch torque;

[0140] Step S36: Determine whether the engine speed of the hybrid vehicle is less than the target idle speed. If so, execute steps S37 and S38 in sequence; otherwise, execute step S391.

[0141] Step S37: Determine the anti-stalling clutch torque by referring to a table based on the rate of change of engine speed and the difference between engine speed and target idle speed.

[0142] Step S38: Take the smaller of the first requested clutch torque and the anti-stalling clutch torque to obtain the starting clutch requested torque;

[0143] Step S39: Determine whether the engine speed is greater than or equal to the target idle speed. If so, use the first pre-requested clutch torque as the starting clutch request torque; otherwise, take the smaller of the first pre-requested clutch torque and the anti-stalling clutch torque to obtain the starting clutch request torque.

[0144] Step S391: The first clutch torque to be requested is taken as the starting clutch request torque.

[0145] In step S31, setting upper and lower limits for the basic starting torque means that the basic starting torque must be limited to between the engine's maximum torque and minimum torque.

[0146] In step S32, the pre-engagement torque is determined as follows: The current vehicle speed of the hybrid vehicle is obtained; a first preset mapping table storing the relationship between vehicle speed and pre-engagement torque is consulted to determine the pre-engagement torque corresponding to the current vehicle speed. This first preset mapping table is an empirical table, such as Table 1 below:

[0147] Table 1

[0148] Current vehicle speed (km / h) 0 2 4 6 Initial engagement torque (Nm) 3 2 1 0

[0149] Figure 4 A schematic flowchart illustrating a method for obtaining the compensation torque of a starting clutch according to Embodiment 1 of the present invention is shown. Figure 4 As shown, the acquisition method includes:

[0150] Step S321: Select the target speed calculation method corresponding to the starting mode from a number of preset target speed calculation methods according to the starting mode of the hybrid vehicle, and use the target speed calculation method to calculate the target engine speed for the next cycle.

[0151] Step S322: Limit the target engine speed to upper and lower limits to obtain the target engine speed limit.

[0152] Step S323: Subtract the actual engine speed from the target engine speed limit to obtain the target engine speed difference;

[0153] Step S324: Query the target P-term coefficient corresponding to the target engine speed difference from the second preset mapping table that stores the relationship between engine speed difference and P-term coefficient;

[0154] Step S325: Multiply the target P-term coefficient by the target engine speed difference, and then multiply by the preset engine rotational inertia to obtain the P-term torque.

[0155] Step S326: Negate the torque of term P to obtain the starting clutch compensation torque.

[0156] In step S321, when the starting method is either accelerator start or launch start, the target engine speed is calculated using the first target speed calculation method, such as... Figure 5 As shown, the method for calculating the first target rotational speed includes:

[0157] Step 3211: Obtain the sum of the torques of the engine and motor of the hybrid vehicle to get the overall torque;

[0158] Step 3212: Take the smaller of the overall torque and the engine requested torque to obtain the target smaller torque;

[0159] Step 3213: Obtain the temperatures of the clutch and transmission;

[0160] Step 3214: When the temperature of the clutch is less than 185°C and the temperature of the transmission is less than 100°C, query the target engine speed corresponding to the target minimum torque and the current engine requested torque from the first preset relationship table that stores the relationship between the minimum torque, the engine requested torque and the engine speed.

[0161] Step 3215: When the temperature of the clutch is greater than 200°C and the temperature of the gearbox is greater than 110°C, query the target engine speed corresponding to the target minimum torque and the current engine requested torque from the second preset relationship table that stores the relationship between the minimum torque, the engine requested torque and the engine speed. The second preset relationship table is different from the first preset relationship table.

[0162] In step S3212, the requested engine torque is the filtered crankshaft torque. In step S3214, the first preset relationship table can be, for example, the following Table 2:

[0163] Table 2

[0164] x / y 0 1125 1250 1500 1750 2000 2250 2375 2500 3300 7000 10 900 1125 1250 1500 1750 2000 2250 2375 2500 3300 7000 25 1100 1300 1375 1500 1750 2000 2250 2375 2500 3300 7000 50 1600 1600 1600 1600 1800 2000 2250 2375 2500 3300 7000 100 1600 1600 1600 1600 1800 2000 2250 2375 2500 3300 7000 150 1800 1800 1800 1800 1800 2000 2250 2375 2500 3300 7000 200 1800 1800 1800 1800 1800 2000 2250 2375 2500 3300 7000 250 1800 1800 1800 1800 1800 2000 2250 2375 2500 3300 7000

[0165] In Table 2, x represents the minimum torque, y represents the engine speed, and the value determined by x and y together is the requested engine torque. The target minimum torque is one of the minimum torque values.

[0166] In step S3215, the second preset relationship table can be, for example, the following Table 3:

[0167] Table 3

[0168] x / y 0 1150 1500 1750 2000 2500 3800 7000 50 950 1150 1500 1750 2000 2500 3800 7000 100 1050 1425 1500 1750 2000 2500 3800 7000 150 1150 1441 1500 1750 2000 2500 3800 7000 200 1250 1458 1500 1750 2000 2500 3800 7000 250 1350 1475 1500 1750 2000 2500 3800 7000 300 1450 1491 1500 1750 2000 2500 3800 7000 330 1450 1491 1500 1750 2000 2500 3800 7000

[0169] In Table 3, x represents the minimum torque, y represents the engine speed, and the value determined by x and y together is the requested engine torque. The target minimum torque is one of the minimum torque values.

[0170] The data settings in the first and second preset relationship tables can prevent engine overheating.

[0171] In step S321, when the starting mode is neutral coasting start, the target engine speed is calculated using the second target speed calculation method, such as... Figure 6 As shown, the method for calculating the second target rotational speed includes:

[0172] S3211', obtains the starting acceleration of the hybrid vehicle when it starts;

[0173] S3212' compares the starting acceleration with the preset acceleration;

[0174] S3213', When the starting acceleration is less than the preset acceleration, query the target engine speed for the next cycle corresponding to the current engine speed from the third preset relationship table that stores the relationship between the current engine speed and the engine speed of the next cycle;

[0175] S3214' When the starting acceleration is greater than or equal to the preset acceleration, the target engine speed for the next cycle corresponding to the current engine speed is queried from the fourth preset relationship table which stores the relationship between the current engine speed and the target engine speed for the next cycle. The fourth preset relationship table is different from the third preset relationship table.

[0176] In step S3212', the preset acceleration can be, for example, 0.3 m / s². 2 To prevent the engine speed from dropping too quickly below the target speed, the target engine speed for the next cycle is set to be slightly higher than the current engine speed, such as 50 rpm. This third preset relationship table can be, for example, Table 4 below:

[0177] Table 4

[0178]

[0179] The engine speed in Table 4 is in rpm.

[0180] In step S3214', the fourth preset relationship table can be, for example, the following Table 5:

[0181] Table 5

[0182]

[0183] The engine speeds in Table 5 are in rpm.

[0184] In step S322, upper and lower limits are set for the target engine speed. The upper limit is the engine speed plus a speed compensation amount based on vehicle speed. When the vehicle speed exceeds a certain value, the speed compensation amount can be zero. Table 6 below shows an example of how the current vehicle speed and the upper limit of the target engine speed satisfy certain conditions.

[0185] Table 6

[0186] x 10 15 30 35 z 3000 1500 1000 0

[0187] In Table 6, x represents the current vehicle speed in km / h, and y represents the target engine speed in rpm.

[0188] The target engine speed is limited by upper and lower limits. The lower limit is the greater of the engine speed and the target idle speed (i.e., when the vehicle is in P gear and the engine speed is 900-1200 RPM).

[0189] In step S324, when the vehicle is activated for start-up, the start-up engine compensation torque is equal to the P-direction torque and equal to -1 * the start-up clutch compensation torque. When the vehicle is not activated for start-up, the start-up clutch compensation torque gradually decreases to zero at a certain rate, such as 5 Nm / s. The second preset mapping table can be, for example, Table 7 below:

[0190] Table 7

[0191]

[0192] When the target engine speed limit is greater than the actual engine speed, the P-term torque is positive. At this time, the engine needs to increase torque, and the clutch torque needs to decrease. Therefore, the starting clutch compensation torque should be negative when calculating the starting engine compensation torque, while the starting engine compensation torque is equal to the P-term torque.

[0193] In step S34, the requested torque of the brake clutch is determined by querying a relationship table that stores the relationship between the crankshaft-end braking force, the first pre-requested clutch torque, and the requested brake clutch torque. This relationship table is an empirical table, and for example, it could be Table 8 below:

[0194] Table 8

[0195]

[0196]

[0197] In Table 8, x represents the crankshaft-end braking force, and y represents the first pre-requested clutch torque. The value determined by x and y together is the brake clutch request torque. Therefore, the method of the present invention takes into account the braking situation during the start-up process.

[0198] In step S37, the anti-stalling clutch torque is determined by querying a relationship table that stores the relationship between the rate of change of engine speed, the difference between engine speed and target idle speed, and the anti-stalling clutch torque. This relationship table could be, for example, Table 9 below:

[0199] Table 9

[0200] x / y -450 -250 -150 -50 0 200 500 1000 -1000 0 0 0 100 150 300 500 500 -500 0 0 50 100 150 300 500 500 0 0 0 100 100 150 300 500 500 500 0 0 100 100 150 300 500 500 1000 0 0 100 100 150 300 500 500

[0201] In Table 9, x represents the rate of change of engine speed, and y represents the difference between engine speed and target idle speed. The value determined by x and y is the anti-stalling clutch torque. Therefore, the present invention adds an anti-stalling protection function. When the engine speed is lower than the target idle speed, the clutch torque should be reduced to prevent the engine from being dragged and stalled, thereby avoiding engine stalling during start-up.

[0202] 2. Hybrid vehicles start by coasting in neutral.

[0203] In this starting method, such as Figure 7 As shown, step S300 includes:

[0204] Step S301: Take the larger value between the basic starting torque and zero, and then apply upper and lower limits to the larger value to obtain the second starting limit torque;

[0205] Step S302: Determine whether the brake pedal of the hybrid vehicle is pressed. If so, proceed to steps S303 to S306; otherwise, proceed to step S307.

[0206] Step S303: Take the smaller of the second starting limit torque and the brake clutch request torque to obtain the second requested clutch torque;

[0207] Step S304: Determine whether the engine speed is less than the target idle speed. If so, proceed to steps S305 and S306; otherwise, proceed to step S308.

[0208] Step S305: When the engine speed of the hybrid vehicle is less than the target idle speed, the anti-stalling clutch torque is determined by referring to a table based on the rate of change of engine speed and the difference between engine speed and target idle speed.

[0209] Step S306: Take the smaller of the second requested clutch torque and the anti-stalling clutch torque to obtain the starting clutch requested torque;

[0210] Step S307: Determine whether the engine speed is less than the target idle speed. If so, take the smaller of the second start-up limit torque and the anti-stalling clutch torque to obtain the start-up clutch request torque. Otherwise, use the second start-up limit torque as the start-up clutch request torque.

[0211] Step S308: The second requested clutch torque is used as the starting clutch requested torque.

[0212] The purpose of step S301, which takes the larger value between the starting basic torque and zero, is to prevent the clutch torque from dropping to a negative value and completely disengaging.

[0213] The calculation methods for the starting basic torque, brake clutch request torque, and anti-stalling clutch torque in steps S301 to S307 are consistent with the calculation methods for the corresponding torques in the aforementioned hybrid vehicle starting method of pressing the accelerator pedal, and will not be repeated here.

[0214] 3. Hybrid vehicles use a launch control system for starting.

[0215] In this starting method, such as Figure 8 As shown, step S300 includes:

[0216] Step S310: Add the starting base torque to the starting pre-engagement torque of the hybrid vehicle and the starting clutch compensation torque to obtain the second pre-requested clutch torque.

[0217] Step S320: Determine whether the engine speed of the hybrid vehicle is less than the target idle speed. If so, proceed to steps S330 and S340; otherwise, proceed to step S350.

[0218] Step S330: Determine the anti-stalling clutch torque by referring to a table based on the rate of change of engine speed and the difference between engine speed and target idle speed.

[0219] Step S340: Take the smaller of the second pre-requested clutch torque and the anti-stalling clutch torque to obtain the starting clutch request torque;

[0220] Step S350: The second pre-requested clutch torque is used as the starting clutch request torque.

[0221] The calculation methods for the starting basic torque, starting pre-engagement torque, starting clutch compensation torque, and anti-stalling clutch torque in steps S310 to S340 are consistent with the calculation methods for the corresponding torques in the aforementioned hybrid vehicle starting method of pressing the accelerator pedal, and will not be repeated here.

[0222] II. The clutch is in fully engaged condition.

[0223] Under this condition, steps S200 and S300 include: determining whether the hybrid vehicle meets the overheat protection conditions; when it is determined that the hybrid vehicle meets the overheat protection conditions, subtracting the preset overheat protection offset torque from the engine requested torque to obtain the starting basic torque, and using the starting basic torque as the starting clutch requested torque; when the hybrid vehicle does not meet the overheat protection conditions, using the engine requested torque as the starting clutch requested torque.

[0224] The overheat protection conditions are the same as those for the aforementioned clutch being in a partially engaged state and the transmission being in gear, and will not be repeated here.

[0225] 3. The clutch is not fully engaged and the transmission is not in gear.

[0226] Under this condition, the starting clutch torque is determined to be zero.

[0227] According to the solution of the present invention, by setting multiple starting control modes during the starting process, specifically neutral coasting starting mode, launch starting mode and accelerator starting mode, overheating conditions and braking conditions are handled in each starting mode, and anti-stalling protection function is also added, thereby increasing the power and safety of the system, and improving the starting response.

[0228] The features of the hybrid vehicle parallel start control system in this embodiment correspond one-to-one with those of the aforementioned hybrid vehicle parallel start control method, and will not be repeated here.

[0229] The characteristics of the hybrid vehicle in this embodiment correspond one-to-one with the characteristics of the hybrid vehicle parallel start control system, which will not be repeated here.

[0230] Example 2:

[0231] The difference between this second embodiment and the first embodiment is that this second embodiment also performs engine start-up control. The specific control method for engine start-up control is described in detail below.

[0232] like Figure 9 As shown, the parallel start control method for hybrid vehicles also includes:

[0233] Step S500: When the clutch is fully engaged, or when the clutch is not fully engaged and the transmission is out of gear, determine that the engine compensation torque is zero.

[0234] Step S600: When the clutch is not fully engaged and the gearbox is in gear, the engine compensation torque is calculated using the engine compensation torque calculation method.

[0235] Step S700: Add the engine compensation torque to the engine requested torque to obtain the engine target torque;

[0236] In step S800, when the brake pedal of the hybrid vehicle is depressed, the target torque of the engine is limited to obtain the starting engine request torque.

[0237] Step S900: Perform start-up control on the engine based on the torque requested by the starting engine.

[0238] like Figure 10 As shown, in step S600, the method for calculating the engine compensation torque includes:

[0239] Step S601: Determine whether the hybrid vehicle meets the overheat protection conditions. If it does, proceed to step S602; otherwise, proceed to step S603.

[0240] Step S602: Add the starting pre-engagement torque of the hybrid vehicle to the starting engine compensation torque, and add the preset overheat protection offset torque to obtain the engine compensation torque, wherein the starting engine compensation torque is equal to the P-term torque of the hybrid vehicle.

[0241] Step S603: Add the starting pre-engagement torque to the starting engine compensation torque to obtain the engine compensation torque.

[0242] The method for limiting the engine target torque in step S800 is as follows: when the brake pedal of the hybrid vehicle is pressed, the brake clutch request torque when the brake pedal is pressed is determined; the smaller of the engine target torque and the brake engine request torque is taken to obtain the starting engine request torque.

[0243] The calculation methods for starting engine compensation torque and starting pre-engagement torque in steps S602 and S603 are consistent with the calculation methods for the corresponding torques in Example 1, and will not be repeated here.

[0244] The features of the hybrid vehicle parallel start control system in this embodiment correspond one-to-one with those of the aforementioned hybrid vehicle parallel start control method, and will not be repeated here.

[0245] The characteristics of the hybrid vehicle in this embodiment correspond one-to-one with the characteristics of the hybrid vehicle parallel start control system, which will not be repeated here.

[0246] According to the solution of the present invention, by controlling the engine torque, it is possible to further prevent engine stalling and further improve the responsiveness, power and safety during the start-up process.

[0247] Therefore, those skilled in the art should recognize that although exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications conforming to the principles of the present invention can be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Thus, the scope of the present invention should be understood and recognized as covering all such other variations or modifications.

Claims

1. A method for parallel start control of a hybrid vehicle, comprising the following steps: The current operating conditions of the clutch and transmission of the hybrid vehicle, the engine torque requested by the hybrid vehicle, and the starting method of the hybrid vehicle are obtained. Based on the current operating conditions of the clutch and the transmission, a judgment is made as to whether the hybrid vehicle meets the overheat protection conditions, and the starting basic torque is determined based on the judgment result and the engine requested torque. The starting clutch request torque is determined based on the starting base torque according to the starting method of the hybrid vehicle; The clutch is started by controlling its start-up based on the requested torque of the start-up clutch. The starting methods of the hybrid vehicle include accelerator start, neutral coasting start, or launch start; When the hybrid vehicle starts using the accelerator pedal, the step of determining the starting clutch request torque based on the starting base torque according to the starting method of the hybrid vehicle includes: The starting basic torque is limited by upper and lower limits to obtain the first starting limit torque; The first pre-engagement torque is obtained by adding the first start-up limiting torque to the start-up pre-engagement torque and the start-up clutch compensation torque of the hybrid vehicle. When the brake pedal of the hybrid vehicle is depressed, the brake clutch request torque when the brake pedal is depressed is determined based on the magnitude of the brake force at the crankshaft end of the hybrid vehicle and the first pre-requested clutch torque. The smaller of the first pre-requested clutch torque and the brake clutch requested torque is taken to obtain the first requested clutch torque; When the engine speed of the hybrid vehicle is less than the target idle speed, the anti-stalling clutch torque is determined by looking up a table based on the rate of change of the engine speed and the difference between the engine speed and the target idle speed. The starting clutch request torque is obtained by taking the smaller of the first requested clutch torque and the anti-stalling clutch torque. When the hybrid vehicle starts using a coasting start in neutral, the step of determining the starting clutch request torque based on the starting base torque according to the starting mode of the hybrid vehicle includes: The larger value between the basic starting torque and zero is taken, and then the larger value is subject to upper and lower limits to obtain the second starting limit torque. When the brake pedal of the hybrid vehicle is depressed, the smaller of the second start-up limiting torque and the brake clutch request torque is taken to obtain the second requested clutch torque. When the engine speed of the hybrid vehicle is less than the target idle speed, the anti-stalling clutch torque is determined by looking up a table based on the rate of change of the engine speed and the difference between the engine speed and the target idle speed. The starting clutch request torque is obtained by taking the smaller of the second requested clutch torque and the anti-stalling clutch torque. or, When the hybrid vehicle uses a launch control method, the step of determining the launch clutch request torque based on the basic launch torque according to the launch mode of the hybrid vehicle includes: The second pre-requested clutch torque is obtained by adding the starting base torque to the starting pre-engagement torque and the starting clutch compensation torque of the hybrid vehicle. When the engine speed of the hybrid vehicle is less than the target idle speed, the anti-stalling clutch torque is determined by looking up a table based on the rate of change of the engine speed and the difference between the engine speed and the target idle speed. The starting clutch request torque is obtained by taking the smaller of the second pre-requested clutch torque and the anti-stalling clutch torque. When the engine speed of the hybrid vehicle is greater than or equal to the target idle speed, the second pre-requested clutch torque is used as the start-up clutch request torque.

2. The parallel start control method for hybrid vehicles according to claim 1, wherein, The step of determining whether the hybrid vehicle meets the overheat protection conditions based on the current operating conditions of the clutch and the transmission, and determining the starting basic torque based on the determination result and the engine requested torque, includes: When the clutch is not fully engaged and the transmission is in gear, determine whether the hybrid vehicle meets the overheat protection conditions. When it is determined that the hybrid vehicle meets the overheat protection conditions, the engine requested torque is subtracted from the preset overheat protection offset torque to obtain the starting basic torque.

3. The parallel start control method for hybrid vehicles according to claim 2, wherein, When the hybrid vehicle starts using an accelerator pedal, the step of determining the starting clutch request torque based on the starting basic torque according to the starting method of the hybrid vehicle further includes: When the brake pedal of the hybrid vehicle is not depressed and the engine speed is greater than or equal to the target idle speed, the first pre-requested clutch torque is used as the start-up clutch request torque. When the brake pedal of the hybrid vehicle is not depressed and the engine speed is less than the target idle speed, the starting clutch request torque is obtained by taking the smaller of the first pre-requested clutch torque and the anti-stalling clutch torque. When the brake pedal of the hybrid vehicle is depressed and the engine speed is greater than or equal to the target idle speed, the first requested clutch torque is used as the starting clutch requested torque.

4. The parallel start control method for hybrid vehicles according to claim 2, wherein, When the hybrid vehicle's starting method is a coasting start, the step of determining the starting clutch request torque based on the starting basic torque according to the hybrid vehicle's starting method further includes: When the brake pedal of the hybrid vehicle is not depressed and the engine speed is greater than or equal to the target idle speed, the second start-up limiting torque is used as the start-up clutch request torque. When the brake pedal of the hybrid vehicle is not depressed and the engine speed is less than the target idle speed, the starting clutch request torque is obtained by taking the smaller of the second start-up limiting torque and the anti-stalling clutch torque. When the brake pedal of the hybrid vehicle is depressed and the engine speed is greater than or equal to the target idle speed, the second requested clutch torque is used as the starting clutch requested torque.

5. The parallel start control method for hybrid vehicles according to any one of claims 1-4, wherein, The starting clutch compensation torque is obtained in the following way: Based on the starting method of the hybrid vehicle, a target speed calculation method corresponding to the starting method is selected from a plurality of preset target speed calculation methods, and the target engine speed for the next cycle is calculated using the target speed calculation method. The target engine speed is limited by upper and lower limits to obtain the target engine speed limit. Subtract the actual engine speed from the target engine speed limit to obtain the target engine speed difference; Query the target P-term coefficient corresponding to the target engine speed difference from the second preset mapping table that stores the relationship between engine speed difference and P-term coefficient; Multiply the target P-term coefficient by the target engine speed difference, and then multiply by the preset engine rotational inertia to obtain the P-term torque; The starting clutch compensation torque is obtained by taking the negative of the torque term P.

6. The parallel start control method for hybrid vehicles according to claim 5, wherein, The step of selecting a target engine speed calculation method corresponding to the starting mode from a plurality of preset target speed calculation methods based on the starting mode of the hybrid vehicle, and using the target engine speed calculation method to calculate the target engine speed for the next cycle includes: when the starting mode of the hybrid vehicle is a throttle start mode or a launch start mode, selecting a first target speed calculation method to calculate the target engine speed, the first target speed calculation method including the following steps: The sum of the torques of the engine and the electric motor of the hybrid vehicle is obtained to get the overall torque; The smaller of the overall torque and the engine-requested torque is taken to obtain the target smaller torque. Obtain the temperatures of the clutch and the gearbox; When the temperature of the clutch is less than 185°C and the temperature of the gearbox is less than 100°C, the target engine speed corresponding to the target minimum torque and the current engine requested torque is queried from a first preset relationship table that stores the relationship between minimum torque, engine requested torque and engine speed. When the temperature of the clutch is greater than 200°C and the temperature of the gearbox is greater than 110°C, the target engine speed corresponding to the target minimum torque and the current engine requested torque is queried from a second preset relationship table that stores the relationship between the minimum torque, the engine requested torque and the engine speed. The second preset relationship table is different from the first preset relationship table.

7. The parallel start control method for hybrid vehicles according to claim 5, wherein, The step of selecting a target engine speed calculation method corresponding to the starting mode from a plurality of preset target speed calculation methods based on the starting mode of the hybrid vehicle, and using the target engine speed calculation method to calculate the target engine speed for the next cycle includes: when the starting mode of the hybrid vehicle is a coasting start mode, selecting a second target engine speed calculation method to calculate the target engine speed, the second target engine speed calculation method including the following steps: Obtain the starting acceleration of the hybrid vehicle at start-up; The starting acceleration is compared with the preset acceleration; When the starting acceleration is less than the preset acceleration, the target engine speed for the next cycle corresponding to the current engine speed is queried from a third preset relationship table that stores the relationship between the current engine speed and the engine speed of the next cycle. When the starting acceleration is greater than or equal to the preset acceleration, the target engine speed for the next cycle corresponding to the current engine speed is queried from the fourth preset relationship table, which stores the relationship between the current engine speed and the target engine speed for the next cycle. The fourth preset relationship table is different from the third preset relationship table.

8. The parallel start control method for hybrid vehicles according to claim 1, wherein the hybrid vehicle is judged to meet the overheat protection conditions based on the current operating conditions of the clutch and the transmission, and the starting basic torque is determined based on the judgment result and the requested torque of the engine; The step of determining the starting clutch request torque based on the starting base torque according to the starting method of the hybrid vehicle includes: When the clutch is in a fully engaged state, determine whether the hybrid vehicle meets the overheat protection conditions. When it is determined that the hybrid vehicle meets the overheat protection conditions, the engine requested torque is subtracted from the preset overheat protection offset torque to obtain the starting basic torque, and the starting basic torque is used as the starting clutch requested torque. When the hybrid vehicle does not meet the overheat protection conditions, the engine requested torque is used as the starting clutch requested torque.

9. The parallel start control method for hybrid vehicles according to claim 2 or 8, wherein, The overheat protection condition is determined to be satisfied when the following conditions are met simultaneously: The temperature of the clutch is greater than or equal to 220°C, and the temperature of the gearbox is greater than or equal to 120°C. The hybrid vehicle can start by either pressing the accelerator or by launching. When the brake pedal of the hybrid vehicle is depressed, the rate of change of the engine's requested torque is less than a first preset rate of change; when the brake pedal is not depressed, the rate of change of the engine's requested torque is less than a second preset rate of change; and the first preset rate of change is less than the second preset rate of change. The difference between the maximum engine torque limit corresponding to the current engine speed and the requested engine torque of the hybrid vehicle is greater than the preset torque value. The current speed of the hybrid vehicle is less than or equal to the preset speed.

10. The parallel start control method for hybrid vehicles according to claim 1, further comprising the following steps: When the clutch is not fully engaged and the transmission is in off-gear mode, the starting clutch is determined to have a torque of zero.

11. The parallel start control method for hybrid vehicles according to claim 1, further comprising the following steps: When the clutch is fully engaged, or when the clutch is not fully engaged and the transmission is in off-gear mode, the engine compensation torque is determined to be zero. When the clutch is not fully engaged and the gearbox is in gear, the engine compensation torque is calculated using the engine compensation torque calculation method. The engine target torque is obtained by adding the engine requested torque to the engine compensated torque; When the brake pedal of the hybrid vehicle is depressed, the target torque of the engine is limited to obtain the starting engine request torque. The engine is controlled to start based on the requested torque from the starting engine.

12. The parallel start control method for hybrid vehicles according to claim 11, wherein, The method for calculating engine compensation torque includes the following steps: When the hybrid vehicle meets the overheat protection condition, the starting pre-engagement torque of the hybrid vehicle is added to the starting engine compensation torque, and then the preset overheat protection offset torque is added to obtain the engine compensation torque, wherein the starting engine compensation torque is equal to the P-term torque of the hybrid vehicle. When the hybrid vehicle does not meet the overheat protection conditions, the starting pre-engagement torque is added to the starting engine compensation torque to obtain the engine compensation torque.

13. The parallel start control method for hybrid vehicles according to claim 11, wherein, In the step of limiting the target torque of the engine to obtain the starting engine request torque when the brake pedal of the hybrid vehicle is depressed, the method for limiting the target torque of the engine is as follows: When the brake pedal of the hybrid vehicle is depressed, determine the brake clutch request torque when the brake pedal is depressed. The starting engine requested torque is obtained by taking the smaller of the engine target torque and the braking engine requested torque.

14. The parallel start control method for hybrid vehicles according to claim 1 or 12, wherein, The initial engagement torque is determined in the following way: Obtain the current speed of the hybrid vehicle; The system queries a first preset mapping table that stores the relationship between vehicle speed and pre-engagement torque to determine the pre-engagement torque corresponding to the current vehicle speed.

15. A parallel start control system for a hybrid vehicle, comprising a control device, the control device including a memory and a processor, the memory storing a control program, the control program being executed by the processor to implement the parallel start control method for a hybrid vehicle according to any one of claims 1-14.

16. A hybrid vehicle, comprising the hybrid vehicle parallel start control system of claim 15.

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