Dual-motor hybrid parallel mode clutch pre-charge oil control method

Abstract

This invention discloses a clutch pre-charge oil control method for dual-motor hybrid parallel mode, comprising the following steps: S1. The vehicle control unit acquires multiple signals of the current vehicle; S2. Determines the activation conditions for clutch pre-charge oil control in parallel mode; S3. Pre-charges the clutch; S4. Records the number of clutch pre-charges; S5. Maintains clutch oil pressure; S6. Reduces clutch oil pressure. This method is used to reduce shift time overhead in parallel mode, improve vehicle acceleration performance, enhance vehicle power, and improve driving comfort.

Description

Technical Field

[0001] This invention relates to the field of hybrid vehicle control technology, specifically to a method for pre-charging oil control of the clutch in a dual-motor hybrid parallel mode. Background Technology

[0002] In recent years, the world has faced increasingly prominent problems such as energy shortages and environmental pollution, while traditional gasoline-powered vehicles suffer from low efficiency of internal combustion engines, serious exhaust emissions, and high energy consumption. To reduce environmental pollution and energy consumption, major automakers worldwide are increasing their research and development efforts on hybrid vehicles.

[0003] In parallel mode, the engine output power of a hybrid electric vehicle can be directly applied to the drive wheels without the need for mechanical energy to be converted into electrical energy. Therefore, the parallel mode of a hybrid electric vehicle has a high conversion efficiency. Shift control is a very important action in the parallel mode of a hybrid electric vehicle, which has a great impact on the acceleration performance of the hybrid electric vehicle. Therefore, reducing the shift time in the parallel mode of a hybrid electric vehicle is very important for improving the acceleration performance of the hybrid electric vehicle in the parallel mode. Summary of the Invention

[0004] This invention provides a clutch pre-filling oil control method for dual-motor hybrid parallel mode, which reduces the shifting time overhead of the vehicle in parallel mode, improves vehicle acceleration performance, enhances vehicle power, and improves vehicle ride comfort.

[0005] The technical solution to the above problem is as follows:

[0006] A method for pre-charging oil control of the clutch in a dual-motor hybrid parallel mode includes the following steps:

[0007] S1. The vehicle control unit acquires multiple signals from the current vehicle;

[0008] S2. Determine the activation conditions for the parallel mode clutch pre-charge oil control. The vehicle control unit determines whether the vehicle status meets the requirements for the activation of the parallel mode clutch pre-charge oil control. If it does, the parallel mode clutch pre-charge oil control is activated. If it does not, the system waits for the parallel mode clutch pre-charge oil control to be activated.

[0009] S3. Clutch pre-charge: The vehicle control unit controls the increase of clutch pressure based on the actual crankshaft speed, actual clutch pressure, and transmission oil temperature. When the actual clutch pressure reaches the set clutch pre-charge pressure threshold and is maintained for a certain period of time, the clutch pre-charge is successful, and the clutch pre-charge control switches to the clutch pressure maintenance stage. If the actual clutch pressure does not reach the set clutch pre-charge pressure threshold within the specified time, the clutch pre-charge fails, and the clutch pre-charge control switches to the clutch pre-charge count recording stage.

[0010] S4. Record the number of times the clutch is pre-charged with oil;

[0011] S5. Maintain clutch oil pressure. The transmission control unit monitors the actual clutch pressure in real time and controls the actual clutch pressure to remain within the deviation range of the clutch pre-charge oil pressure threshold.

[0012] S6. Reduce clutch oil pressure. The transmission control unit requests to control the clutch pressure to decrease with the first clutch pressure slope. When the actual clutch pressure drops to 0 and is maintained for a second time, the clutch pre-fill control is disengaged.

[0013] Furthermore, in step S1, the vehicle control unit acquires multiple signals from the current vehicle, including:

[0014] (a) The vehicle control unit obtains the gear shift position from the electronic gear shifter via the local area network control bus;

[0015] (b) The vehicle control unit obtains the actual crankshaft speed from the engine control unit via the local area network control bus;

[0016] (c) The vehicle control unit obtains the vehicle speed from the vehicle stability system via the local area network control bus;

[0017] (d) The vehicle control unit obtains the actual clutch pressure, transmission oil temperature, actual gear, clutch status, and shift status from the transmission control unit via the local area network control bus;

[0018] (e) The vehicle control unit obtains the vehicle powertrain status and vehicle operating mode from the internal vehicle system coordination module;

[0019] (f) The vehicle control unit obtains the target gear from the internal driving intention module.

[0020] Furthermore, in step S2, the activation conditions must meet the following requirements: the key switch is ON, the gear lever is in D position, the clutch is open, the gear shifting state is gear engagement, the actual gear is neutral, the vehicle power system is activated, the vehicle operating mode is parallel, and the target gear is forward.

[0021] Furthermore, in S3, the specific steps by which the vehicle control unit controls the clutch pressure to rise to the clutch pre-charge pressure threshold based on the actual crankshaft speed, actual clutch pressure, and transmission oil temperature are as follows:

[0022] S31, Clutch pre-charge oil rapid control: The vehicle control unit queries the two-dimensional table of actual crankshaft speed and transmission oil temperature based on the actual crankshaft speed and transmission oil temperature to obtain the clutch pressure rise slope of clutch pre-charge oil rapid control. The vehicle control unit controls the clutch pressure rise according to the clutch pressure rise slope of clutch pre-charge oil rapid control. When the actual clutch pressure reaches the clutch pre-charge oil set threshold minus the set deviation, the clutch pre-charge oil control is transferred to clutch pre-charge oil closed-loop control.

[0023] S32, clutch pre-charge oil closed-loop control: The vehicle control unit controls the increase of clutch pressure through a proportional-integral-derivative controller based on the difference and slope between the actual clutch pressure and the clutch pre-charge oil set threshold. When the actual clutch pressure reaches the clutch pre-charge oil clutch pressure set threshold and is maintained for a third time, the clutch pre-charge oil is successful, and the clutch pre-charge oil control is transferred to the clutch oil pressure holding stage.

[0024] Furthermore, in step S4, after the vehicle control unit increases the number of clutch pre-charge cycles, if the number of clutch pre-charge cycles is less than or equal to N, then the clutch pre-charge control switches to the clutch pre-charge stage and performs clutch pre-charge again; if the number of clutch pre-charge cycles is greater than N, then the clutch pre-charge control switches to the clutch oil pressure reduction stage.

[0025] The beneficial effects of adopting the above technical solution are as follows:

[0026] This invention employs clutch pre-filling control during gear shifting in parallel mode of a hybrid electric vehicle. It pre-fills the hydraulic system of the clutch with oil and establishes a clutch pressure value with a relatively low torque transmission capacity. This effectively reduces the shifting time in parallel mode, improves vehicle acceleration performance, and thus enhances vehicle power and driving comfort. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of a dual-motor hybrid electric vehicle according to an embodiment of the present invention.

[0028] Figure 2 This is a flowchart of the present invention. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0030] See Figure 1This is a schematic diagram of a dual-motor hybrid power system, including an engine 1, a clutch 2, a generator 3, a transmission 4, a drive motor 5, a reducer 6, a drive axle 7, wheels 8, and a high-voltage battery 9 (exceeding the safe voltage of 60V and below 1000V). The engine 1 is connected to the generator 3 via a first reduction gear mechanism (not shown in the figure). The engine 1 and the generator 3 are connected to the input shaft of the transmission 4 via the clutch 2. The drive motor 5 is coupled to the reducer 4 via a second reduction gear mechanism (not shown in the figure). The output end of the transmission 4 is connected to the drive axle 7 via the reducer 6. The drive axle 7 is connected to the wheels 8. The high-voltage battery 9 is connected to the generator 3 and the drive motor 5 via high-voltage lines.

[0031] like Figure 2 As shown, the dual-motor hybrid parallel mode clutch pre-charge oil control method of the present invention includes the following steps:

[0032] S1. The vehicle control unit acquires multiple signals from the current vehicle. In step S1, the vehicle control unit acquires the following multiple signals from the current vehicle:

[0033] (a) The vehicle control unit obtains the gear shift position from the electronic gear shifter via the local area network control bus;

[0034] (b) The vehicle control unit obtains the actual crankshaft speed (actual engine speed) from the engine control unit via the local area network control bus.

[0035] (c) The vehicle control unit obtains the vehicle speed from the vehicle stability system via the local area network control bus;

[0036] (d) The vehicle control unit obtains the actual clutch pressure, transmission oil temperature, actual gear, clutch status, and shift status from the transmission control unit via the local area network control bus;

[0037] (e) The vehicle control unit obtains the vehicle powertrain status and vehicle operating mode from the internal vehicle system coordination module;

[0038] (f) The vehicle control unit obtains the target gear from the internal driving intention module.

[0039] S2. Determine the activation conditions for the parallel mode clutch pre-charge oil control. The vehicle control unit determines whether the vehicle status meets the requirements for the activation of the parallel mode clutch pre-charge oil control. If it does, the parallel mode clutch pre-charge oil control is activated. If it does not, the system waits for the parallel mode clutch pre-charge oil control to be activated.

[0040] In step S2, the activation conditions include the key switch state, vehicle powertrain state, vehicle powertrain operating mode, and gear lever position. If all the above activation conditions meet the set requirements, the parallel mode clutch pre-charge oil control is activated; if any condition is not met, the parallel mode clutch pre-charge oil control is deactivated. Preferably, the activation conditions must meet the following requirements: the key switch state is ON (ON means open), the gear lever position is D (D means forward gear), the clutch state is open, the gear shift state is the gearbox engagement process, the actual gear is neutral, the vehicle speed is less than a set threshold (e.g., 40 km / h), the vehicle powertrain state is activated, the vehicle operating mode is parallel, and the target gear is forward gear.

[0041] S3. Clutch pre-charge: The vehicle control unit controls the increase of clutch pressure based on the actual crankshaft speed, actual clutch pressure, and transmission oil temperature. When the actual clutch pressure reaches the set clutch pre-charge pressure threshold and is maintained for a certain period of time, the clutch pre-charge is successful, and the clutch pre-charge control transitions to the clutch pressure maintenance phase. If the actual clutch pressure does not reach the set clutch pre-charge pressure threshold within a specified time (e.g., 2-3 seconds, preferably 2 seconds), the clutch pre-charge fails, and the clutch pre-charge control transitions to the clutch pre-charge count recording phase. The first time is 40-80 milliseconds; in this embodiment, 50 milliseconds is preferred.

[0042] In S3, the specific steps by which the vehicle control unit controls the clutch pressure to rise to the clutch pre-charge pressure threshold based on the actual crankshaft speed, actual clutch pressure, and transmission oil temperature are as follows:

[0043] S31, Clutch pre-charge oil rapid control: The vehicle control unit queries the two-dimensional table of actual crankshaft speed and transmission oil temperature based on the actual crankshaft speed and transmission oil temperature to obtain the clutch pressure rise slope of clutch pre-charge oil rapid control. The vehicle control unit controls the clutch pressure rise according to the clutch pressure rise slope of clutch pre-charge oil rapid control. When the actual clutch pressure reaches the clutch pre-charge oil set threshold minus the set deviation, the clutch pre-charge oil control is transferred to clutch pre-charge oil closed-loop control.

[0044] S32, Clutch pre-charge oil closed-loop control: The vehicle control unit controls the increase of clutch pressure via a proportional-integral-derivative (PID) controller based on the difference and slope between the actual clutch pressure and the set clutch pre-charge oil threshold. When the actual clutch pressure reaches the set clutch pre-charge oil pressure threshold and is maintained for a third time, clutch pre-charge is successful, and clutch pre-charge oil control transitions to the clutch pressure holding phase. The third time is 40-80 milliseconds, with 60 milliseconds being preferred.

[0045] S4. Record the number of clutch pre-charge cycles. In step S4, after the vehicle control unit increments the clutch pre-charge cycle by one, if the number of clutch pre-charge cycles is less than or equal to N, then the clutch pre-charge control switches to the clutch pre-charge stage and performs clutch pre-charge again; if the number of clutch pre-charge cycles is greater than N, then the clutch pre-charge control switches to the clutch pressure reduction stage. The value of N is 3-5; in this embodiment, the value of N is preferably 3.

[0046] S5. Maintain clutch oil pressure. The transmission control unit monitors the actual clutch pressure in real time and controls the actual clutch pressure to remain within the deviation range of the clutch pre-charge oil pressure threshold.

[0047] S6. Reduce clutch oil pressure. The transmission control unit requests a decrease in clutch pressure using a first clutch pressure slope of 1-5 bar / s, preferably 1 bar / s. Once the actual clutch pressure drops to 0 and remains there for a second time, the clutch pre-charge control is disengaged. The second time is 40-80 milliseconds, preferably 50 milliseconds.

[0048] Based on the structural characteristics of dual-motor hybrid electric vehicles, this invention employs clutch pre-filling control during gear shifting in parallel mode. This pre-fills the hydraulic system of the clutch with oil and establishes a clutch pressure value with a relatively low torque transmission capacity. This effectively reduces the shifting time in parallel mode, improves vehicle acceleration performance, and thus enhances vehicle power and driving comfort.

[0049] Finally, it should be noted that the above-described embodiments are merely preferred embodiments of the present invention used to illustrate the technical solutions of the present invention, and are not intended to limit them, much less limit the scope of protection of the present invention; although the invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to depart from the scope of protection of the claims.

Claims

1. A method for pre-charging oil control of clutch in a dual-motor hybrid parallel mode, characterized in that, The following steps are involved: S1. The vehicle control unit acquires multiple signals from the current vehicle; S2. Determine the activation conditions for the parallel mode clutch pre-charge oil control. The vehicle control unit determines whether the vehicle status meets the requirements for the activation of the parallel mode clutch pre-charge oil control. If it does, the parallel mode clutch pre-charge oil control is activated. If it does not, the system waits for the parallel mode clutch pre-charge oil control to be activated. S3. Clutch pre-charge: The vehicle control unit controls the increase of clutch pressure based on the actual crankshaft speed, actual clutch pressure, and transmission oil temperature. When the actual clutch pressure reaches the set clutch pre-charge pressure threshold and is maintained for a certain period of time, the clutch pre-charge is successful, and the parallel mode clutch pre-charge control switches to the clutch oil pressure maintenance stage. If the actual clutch pressure does not reach the set clutch pre-charge pressure threshold within the specified time, the clutch pre-charge fails, and the parallel mode clutch pre-charge control switches to the clutch pre-charge count recording stage. S4. When clutch pre-charging fails, record the number of clutch pre-charging attempts. After the vehicle control unit adds one clutch pre-charge oil count, if the clutch pre-charge oil count is less than or equal to N, then the parallel mode clutch pre-charge oil control switches to the clutch pre-charge oil stage and performs clutch pre-charge oil again; if the clutch pre-charge oil count is greater than N, then the parallel mode clutch pre-charge oil control switches to the clutch oil pressure reduction stage. S5. When the clutch pre-charge is successful, during the clutch oil pressure maintenance phase, the transmission control unit monitors the actual clutch pressure in real time and controls the actual clutch pressure to remain within the deviation range of the clutch pre-charge pressure threshold. S6. When the number of clutch pre-charge cycles is greater than N, during the clutch oil pressure reduction phase, the transmission control unit requests control to reduce the clutch pressure with the first clutch pressure slope. When the actual clutch pressure drops to 0 and remains there for a second time, the parallel mode clutch pre-charge control is discontinued.

2. The clutch pre-charging oil control method for dual-motor hybrid parallel mode according to claim 1, characterized in that, In step S1, the vehicle control unit acquires multiple signals from the current vehicle, including: (a) The vehicle control unit obtains the gear shift position from the electronic gear shifter via the local area network control bus; (b) The vehicle control unit obtains the actual crankshaft speed from the engine control unit via the local area network control bus; (c) The vehicle control unit obtains the vehicle speed from the vehicle stability system via the local area network control bus; (d) The vehicle control unit obtains the actual clutch pressure, transmission oil temperature, actual gear, clutch status, and shift status from the transmission control unit via the local area network control bus; (e) The vehicle control unit obtains the vehicle powertrain status and vehicle operating mode from the internal vehicle system coordination module; (f) The vehicle control unit obtains the target gear from the internal driving intention module.

3. The clutch pre-charging oil control method for dual-motor hybrid parallel mode according to claim 1, characterized in that, In step S2, the activation conditions must meet the following requirements: the key switch is ON, the gear lever is in D position, the clutch is open, the gear shift is in gear engagement, the actual gear is neutral, the vehicle power system is activated, the vehicle is in parallel operation mode, and the target gear is forward.

4. The clutch pre-charging oil control method for dual-motor hybrid parallel mode according to claim 1, characterized in that: In S3, the specific steps by which the vehicle control unit controls the clutch pressure to rise to the clutch pre-charge pressure threshold based on the actual crankshaft speed, actual clutch pressure, and transmission oil temperature are as follows: S31, Clutch pre-charge oil rapid control: The vehicle control unit queries the two-dimensional table of actual crankshaft speed and transmission oil temperature to obtain the clutch pressure rise slope of clutch pre-charge oil rapid control. The vehicle control unit controls the clutch pressure rise according to the clutch pressure rise slope of clutch pre-charge oil rapid control. When the actual clutch pressure reaches the clutch pre-charge oil pressure threshold minus the set deviation, the parallel mode clutch pre-charge oil control is transferred to clutch pre-charge oil closed-loop control. S32, clutch pre-charge oil closed-loop control: The vehicle control unit controls the increase of clutch pressure through a proportional-integral-derivative controller based on the difference and slope between the actual clutch pressure and the clutch pre-charge oil set threshold. When the actual clutch pressure reaches the clutch pre-charge oil pressure threshold and is maintained for a first time, the clutch pre-charge oil is successful. In parallel mode, the clutch pre-charge oil control is transferred to the clutch oil pressure holding stage.

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