Vehicle hybrid power system and control method thereof

Abstract

The invention discloses a vehicle hybrid power system and a control method thereof. The system involves an engine, a hybrid power module and a double-input-shaft speed change mechanism, wherein the hybrid power module is composed of a motor, a planetary gear train and a first clutch, the planetary gear train is provided with at least three rotating shafts, the three rotating shafts comprise a rotating shaft X1, a rotating shaft X2 and a rotating shaft X3, axes of the three rotating shafts are on one straight line, the rotating speed of the rotating shaft X2 is between the rotating speed of therotating shaft X1 and the rotating speed of the rotating shaft X3, a first clutch is arranged between any two of the three rotating shafts, a power output shaft of the engine is connected with the rotating shaft X3 or the rotating shaft X1 of the planetary gear train and a second input shaft of the double-input-shaft speed change mechanism, a rotor of the motor is connected with the rotating shaft X1 or the rotating shaft X3, and the rotating shaft X2 is connected with a first input shaft of a double-input-shaft gearbox. According to the system and the method, the transmission efficiency is high, multiple gears are provided, the three-axis double-freedom-degree planetary gear train is introduced, a vehicle is driven to start by the differential between the engine and the motor, starting of the vehicle is stable, the smoothness of gear shifting is good, and the impact of gear shifting is small.

Description

technical field [0001] The invention relates to the technical field of hybrid vehicles, in particular to a hybrid system for vehicles and a control method thereof. Background technique [0002] A hybrid vehicle has two power sources, an engine and a motor. Through the mutual cooperation between the two power sources during vehicle driving, it has both the advantages of traditional fuel vehicles and pure electric vehicles, and becomes the best solution to environmental and energy problems. The car model is the power system with the most industrialization and marketization prospects in electric vehicles. [0003] In the prior art, DCT (Dual Clutch Transmission, abbreviated as DCT) hybrid transmission is widely used in the power drive system of hybrid vehicles, which is composed of adding a motor in front of the dual clutch of DCT (Dual Clutch Transmission), and adding a clutch in front of the motor. Gear transmission, high efficiency, less energy loss caused by clutch draggin...

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Problems solved by technology

[0003] In the prior art, DCT (Dual Clutch Transmission, abbreviated as DCT) hybrid transmission is widely used in the power drive system of hybrid vehicles, which is composed of adding a motor in front of the dual clutch of DCT (Dual Clutch Transmission), and adding a clutch in front of the motor. Gear transmission, high efficiency, less energy loss caused by clutch dragging resistance, less hydraulic energy consumption; engine and motor are driven in parallel, torque is superimposed, and power is good; DCT technology is mature, mass production is realized, and the quality of parts and assemblies is stable , low cost; however, there are the following disadvantages: 1. The dual-clutch control technology is complex, risky and costly; 2. The diameter and volume of the dual-clutch are large, and after adding a motor, the axial length is relatively large, making it difficult to arrange in the engine compartment ;3. When the engine drives the vehicle to start, it is difficult to control the sliding friction of the dual clutch, and it is prone to vibration; when shifting gears, the switching of the two clutches is also likely to cause vibration; There can be 6 or 7 gears; between the low gears, the speed ratio difference is large, and the fuel consumption in urban road conditions is poor

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