Hybrid power system and control method thereof

Abstract

The invention relates to a hybrid power system with multiple power sources and multiple levels of speed ratios and a control method of the hybrid power system. The hybrid power system comprises an engine, a bidirectional controllable overrun clutch, a first motor, a second motor, a multi-speed transmission and a battery pack. One end of the bidirectional controllable overrun clutch is connected with an output shaft of the engine. The other end of the bidirectional controllable overrun clutch is connected with an output shaft of the first motor. A driving part of the multi-speed transmission is connected with the bidirectional controllable overrun clutch. A driven part of the multi-speed transmission is connected with an output shaft of the second motor. The battery pack supplies power to the first motor and the second motor. By means of switching of the modes of the bidirectional controllable overrun clutch and switching of gears of the multi-speed transmission, the multiple driving and energy recovery modes which the multiple power sources can be partially or overall involved in is realized. According to the hybrid power system, control is simplified, the structure is compact, sliding friction energy loss caused by the clutch is avoided, the efficiency of a whole vehicle is improved, the gear ratio of the system lowers the requirement for the performance of the first motor, the fuel economy of the engine is improved, and the energy-saving effect is enhanced.

Description

technical field [0001] The invention belongs to the technical field of electromechanical compound transmission system, especially the hybrid power transmission of motor vehicles, and specifically relates to a kind of hybrid power system with two-way controllable overrunning clutch, multiple power sources including engine and multi-stage speed ratio and its control method. Background technique [0002] A hybrid power system refers to a system in which two or more power sources drive a vehicle individually or jointly through a certain power coupling device. [0003] In the prior art, friction clutches (including dry and wet) or planetary gear mechanisms are commonly used as coupling devices for multiple power sources. Friction clutches only have on-off functions, and are mainly used in parallel hybrid systems. They have the disadvantages of difficult control, high requirements, and easy wear. Slip friction caused by frequent clutch on-off will also cause energy loss. The pl...

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Problems solved by technology

[0005] Existing hybrid system has adopted the scheme of common overrunning clutch: CN101439665 proposes to be provided with one-way overrunning clutch between the engine with starter and the electric motor The solution, which does not have a transmission, greatly limits the scope of application of the system, and is difficult to meet the needs of normal driving of general vehicles

CN101314325 and CN101334076 propose a scheme for setting an overrunning clutch between the first power source (the engine is connected to the first motor) and the second power source (the second motor). Although this problem can be solved by adding a friction clutch between the engine and the first motor, the addition of a clutch increases the size of the system and the difficulty of control, which offsets the compact structure and simplified operation brought by the use of an overrunning clutch The advantages of engineering application scope and value are limited

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