Control method and system for limiting maximum speed of engine and motor of hybrid vehicle

Abstract

The invention provides a control method and system for limiting a maximum speed of an engine and a motor of a hybrid vehicle. The hybrid vehicle includes an engine clutch configured to control power transmission between the engine and the motor. The control method includes determining whether speed of the engine exceeds a predetermined maximum engine speed, determining whether speed of the motor exceeds a predetermined maximum motor speed, limiting the speed of the engine based on a predetermined engine torque profile when the speed of the engine exceeds the predetermined maximum engine speed, and limiting the speed of the motor based on a predetermined motor torque profile when the speed of the engine exceeds the predetermined maximum engine speed.

Description

technical field [0001] The present invention relates to a control method and system for limiting the maximum rotational speed of an engine and an electric motor of a hybrid vehicle. Background technique [0002] Hybrid vehicles run on power from an internal combustion engine and from an electric motor with the help of a battery. In particular, hybrid vehicles are designed to efficiently combine and use power from an internal combustion engine and an electric motor. [0003] For example, if figure 1 As shown, the hybrid vehicle includes: an engine 10; an electric motor 20; an engine clutch 30 controlling power transmission between the engine 10 and the electric motor 20; a transmission 40; a differential gear 50; a battery 60; an integrated starter generator (ISG: Integrated Starter-generator) 70 for electric power; and wheels 80 . [0004] It is also shown in the figure that the hybrid vehicle includes: a hybrid control unit (HCU: Hybrid Control Unit) 200 that controls th...

AI Technical Summary

Problems solved by technology

[0026] Second, it may not be easy to maintain the transmission input speed at the speed value used to limit the maximum speed of the engine or electric motor

That is, when the maximum speed of the engine or electric motor is limited to 6200rpm, the input speed of the transmission may exceed 6200rpm

In this case, it may not be easy to protect the transmission hardware system and the electric power equipment hardware system

[0027] Third, when the engine clutch is locked, it is difficult to maintain consistency in the maximum torque limits of the engine and electric motor due to the speed difference between the engine and electric motor

For example, when the engine is fuel-cut due to the maximum torque limit, the battery's state of charge (SOC: State of Charge) may deteriorate as the electric motor generates additional torque to meet the demand torque

[0028] Fourth, shift shock and shift delay may occur due to drastic changes in the input torque to the transmission

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