Parallel start control method and system for hybrid electric vehicle, and hybrid electric vehicle

Patent metadata

Field	Value
Publication number	US-12509059-B2
Application number	US-202118287938-A
Country	US
Kind code	B2
Filing date	Aug 19, 2021
Priority date	Aug 19, 2021
Publication date	Dec 30, 2025
Grant date	Dec 30, 2025

Abstract

Disclosed are a parallel start control method and system for a hybrid electric vehicle, and a hybrid electric vehicle. The parallel start control method includes: acquiring current working conditions of a clutch and a gearbox of the hybrid electric vehicle, an engine request torque of the hybrid electric vehicle and a start mode of the hybrid electric vehicle; judging whether the hybrid electric vehicle meets an over-heat protection condition according to the current working conditions of the clutch and the gearbox, and determining a start basic torque according to a judging result and the engine request torque; determining a start clutch request torque based on the start basic torque according to the start mode of the hybrid electric vehicle; and conducting start control on the clutch according to the start clutch request torque. The start security, responsiveness and power performance of the hybrid electric vehicle are improved.

First claim

What is claimed is:

1 . A parallel start control method for a hybrid electric vehicle, comprising the following steps:
acquiring current working conditions of a clutch and a gearbox of the hybrid electric vehicle, an engine request torque of the hybrid electric vehicle and a start mode of the hybrid electric vehicle; judging whether the hybrid electric vehicle meets an over-heat protection condition according to the current working conditions of the clutch and the gearbox, and determining a start basic torque according to a judging result and the engine request torque; determining a start clutch request torque based on the start basic torque according to the start mode of the hybrid electric vehicle; and conducting start control on the clutch according to the start clutch request torque.

2 . The parallel start control method for the hybrid electric vehicle according to claim 1 , wherein the step of judging whether the hybrid electric vehicle meets the over-heat protection condition according to the current working conditions of the clutch and the gearbox, and determining the start basic torque according to the judging result and the engine request torque comprises:
when the clutch is in an incompletely engaged working condition and the gearbox is in an in-gear working condition, judging whether the hybrid electric vehicle meets the over-heat protection condition; and when determining that the hybrid electric vehicle meets the over-heat protection condition, subtracting a preset over-heat protection offset torque from the engine request torque, to obtain the start basic torque.

3 . The parallel start control method for the hybrid electric vehicle according to claim 2 , wherein when the start mode of the hybrid electric vehicle is an accelerator pedaling start mode, the step of determining the start clutch request torque based on the start basic torque according to the start mode of the hybrid electric vehicle comprises:
limiting upper and lower limits of the start basic torque, to obtain a first start limiting torque; adding a start pre-engagement torque and a start clutch compensation torque of the hybrid electric vehicle to the first start limiting torque, to obtain a first pre-request clutch torque; when a brake pedal of the hybrid electric vehicle is pressed, determining a brake clutch request torque when the brake pedal is pressed according to a crankshaft brake force and the first pre-request clutch torque of the hybrid electric vehicle; taking a smaller one of the first pre-request clutch torque and the brake clutch request torque as a first to-be-requested clutch torque; when an engine rotation speed of the hybrid electric vehicle is smaller than a target idle rotation speed, determining an anti-flameout clutch torque by looking up a table according to a variation rate of the engine rotation speed and a difference obtained by subtracting the target idle rotation speed from the engine rotation speed; and taking a smaller one of the first to-be-requested clutch torque and the anti-flameout clutch torque as the start clutch request torque.

4 . The parallel start control method for the hybrid electric vehicle according to claim 3 , wherein the step of determining the start clutch request torque based on the start basic torque according to the start mode of the hybrid electric vehicle further comprises:
when the brake pedal of the hybrid electric vehicle is not pressed, and the engine rotation speed is greater than or equal to the target idle rotation speed, taking the first pre-request clutch torque as the start clutch request torque; when the brake pedal of the hybrid electric vehicle is not pressed, and the engine rotation speed is smaller than the target idle rotation speed, taking a smaller one of the first pre-request clutch torque and the anti-flameout clutch torque as the start clutch request torque; and when the brake pedal of the hybrid electric vehicle is pressed, and the engine rotation speed is greater than or equal to the target idle rotation speed, taking the first to-be-requested clutch torque as the start clutch request torque.

5 . The parallel start control method for the hybrid electric vehicle according to claim 3 , wherein the start clutch compensation torque is acquired by:
selecting a target rotation speed calculation method corresponding to the start mode from multiple preset target rotation speed calculation methods according to the start mode of the hybrid electric vehicle, and calculating a target engine rotation speed of a next cycle by using the target rotation speed calculation method; limiting upper and lower limits of the target engine rotation speed, to obtain an engine target limiting rotation speed; subtracting an actual engine rotation speed from the engine target limiting rotation speed, to obtain a target engine rotation speed difference; searching a target P-term coefficient corresponding to the target engine rotation speed difference from a second preset mapping relationship table storing a relationship between an engine rotation speed difference and a P-term coefficient; multiplying the target P-term coefficient with the target engine rotation speed difference, and then multiplying with a preset engine rotation inertia, to obtain a P-term torque; and negating the P-term torque to obtain the start clutch compensation torque.

6 . The parallel start control method for the hybrid electric vehicle according to claim 5 , wherein the step of selecting the target rotation speed calculation method corresponding to the start mode from multiple preset target rotation speed calculation methods according to the start mode of the hybrid electric vehicle, and calculating the target engine rotation speed of the next cycle by using the target rotation speed calculation method comprises: when the start mode of the hybrid electric vehicle is the accelerator pedaling start mode or the launch control start mode, selecting a first target engine rotation speed calculation method to calculate the target engine rotation speed, the first target engine rotation speed calculation method comprising the following steps:
acquiring a torque sum of the engine and motor of the hybrid electric vehicle, to obtain an overall torque; taking a smaller one of the overall torque and the engine request torque, to obtain a target smaller torque; acquiring temperatures of the clutch and the gearbox; when the temperature of the clutch is smaller than 185° C., and the temperature of the gearbox is smaller than 100° C., searching a target engine rotation speed corresponding to the target smaller torque and a current engine request torque from a first preset relationship table storing the relationship between smaller torques, engine request torques and engine rotation speeds; and when the temperature of the clutch is greater than 200° C., and the temperature of the gearbox is greater than 110° C., searching the target engine rotation speed corresponding to the target smaller torque and the current engine request torque from a second preset relationship table storing the relationship between smaller torques, engine request torques and engine rotation speeds, wherein the second preset relationship table is different from the first preset relationship table.

7 . The parallel start control method for the hybrid electric vehicle according to claim 5 , wherein the step of selecting the target rotation speed calculation method corresponding to the start mode from multiple preset target rotation speed calculation methods according to the start mode of the hybrid electric vehicle, and calculating the target engine rotation speed of the next cycle by using the first target rotation speed calculation method comprises: when the start mode of the hybrid elec

Assignees

• Ningbo Geely Royal Engine Components Co Ltd
• Aurobay Tech Co Ltd
• Geely Holding Group Co Ltd

Inventors

• Jing Junchao
• Liu Yiqiang
• Huang Weishan
• Yang Jun
• Zuo Botao
• Yu Xuemei
• Wang Ruiping
• Scholten Ingo

Classifications

• B60Y2300/71

  Limiting transmission input torque · CPC title

• B60Y2300/42

  Control of clutches · CPC title

• B60Y2200/92

  Hybrid vehicles · CPC title

• B60W2710/0666

  Engine torque · CPC title

• B60W2710/027

  Clutch torque · CPC title