A hybrid electric vehicle comprising: an engine; a filter for collecting particulate matter from the engine; a motor provided on a power transmission path between the engine and the drive wheels; a torque converter having a lock-up clutch provided on the power transmission path between the motor and the drive wheels; and a control device, wherein the control device includes: a first determination unit that determines whether there is a request for regeneration control of the filter by a fuel cut in the engine; a second determination unit that determines whether the lock-up clutch cannot be engaged; and a regeneration control unit that, when an affirmative determination is made in the first determination unit and a negative determination is made in the second determination unit, executes auxiliary regeneration control that assists the rotation of the engine by the motor while releasing the lock-up clutch and executing the fuel cut.

A gear-shifting control method includes: determining whether a clutch is overheated; when the clutch is overheated, performing torque unloading, and making a request for transmission gear-shifting; and performing speed regulation on a first electric motor until the speed regulation is completed. By using the method, in a gear-shifting speed regulation stage, transmission gear-shifting can be performed when a clutch is overheated, such that the safety and performance of a gear-shifting process can be improved.

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.

When there is a request for regeneration control of the filter by fuel cut to the engine, regeneration control is performed in an engaged state of the direct coupling clutch. When it is impossible to bring the direct coupling clutch into an engaged state when there is a request for regeneration control, the regeneration control is performed while the rotation of the engine is assisted by the electric motor in the released state of the direct coupling clutch. In addition, in a predetermined state in which a shock due to a rotational fluctuation of the electric motor is likely to occur, the regeneration control accompanied by the rotation assistance of the engine by the electric motor is not performed. Therefore, it is possible to achieve both the suppression of the occurrence of shock caused by the rotation fluctuation of the electric motor and the regeneration of the filter.

A control method is implemented in a vehicle comprising an internal-combustion engine providing a first torque and coupled to a gearbox by a coupling device comprising a hydraulic circuit and delivering a second torque from the first torque in a coupling position, and an electric motor installed between the coupling device and gearbox and producing, from the second torque, a third torque having a negative value opposite to that of the first torque to charge a battery. This method comprises a step (10-20) in which, in the event of a transition between neutral and parking positions during a charging phase, a nullification of the third torque produced is triggered to nullify the first torque before a sudden placement of the coupling device in a decoupling position.