Basic Structure of Hybrid Vehicles

The

Basic Structure of Hybrid Vehicles

The structure of a hybrid vehicle is more complex, and it has the dual components of a conventional vehicle and a pure electric vehicle. As shown in the figure, the hybrid car is equipped with an internal combustion engine, a power battery, a power drive unit, a DC/DC converter, and an on-board charger if it is a plug-in hybrid car.

Since the power battery, DC/DC converter and other components and pure electric vehicles in the structure of the principle of no difference, but the design of the power drive unit is the center of the hybrid car, that is, the vehicle is a reflection of the form of hybrid drive, but also a hybrid car is also an important manifestation of technical performance.

In the hybrid models, medium and heavy hybrid its internal in the traditional internal combustion vehicles on the basis of the main increase in high-voltage power battery packs and improved variable speed drive unit, and for specific vehicle needs to add some other ancillary components.

The structure of the variable speed drive unit

The variable speed drive unit of the hybrid vehicle, unlike the existing automatic or manual transmission, mainly contains:

The three-phase motor used for driving and power generation.

A clutch for power switching.

The gear mechanism used to realize the output power shifting.

There are two widely used types of variable speed drive units for hybrid vehicles, namely the hybrid form of variable speed drive unit represented by the Toyota Prius and the parallel form of variable speed drive unit represented by the BYD Qin.

The mechanism of the mixed-connection VSDU can realize more hybrid drive modes, such as pure electric drive mode, combustion engine and electric motor combined mode, and different combinations of modes under various working conditions, and usually there are two electric motors designed inside this type of VSDU.

The biggest advantage of the parallel variable-speed drive unit mechanism is that it allows the vehicle to continue to be driven by the variable-speed unit even when the internal combustion engine alone fails in the electric drive mode.

The combustion engine is connected to the planetary carrier of the internal planetary gear mechanism.

The MG1 is connected to the sun wheel of the planetary gear mechanism.

MG2 is connected to the ring of the planetary gear mechanism and the output shaft of the vehicle.

From the internal connection relationship, it can be judged that there exists in the gear unit a series form in which the internal combustion engine provides power to MG1 for generating electricity and MG2 is used for driving the vehicle, and there exists a parallel form in which the internal combustion engine and the MG2 drive the vehicle by using the planetary gear mechanism at the same time in the case of the MG1 being fixed. Therefore, it can be judged from such a structure that the Prius uses is a hybrid form.

The electric motor used in a hybrid vehicle is usually a three-phase AC motor, which replaces the generator and starter on a conventional vehicle. When the internal combustion engine needs to be started, the motor inside acts as a starter, driving the combustion engine; when the combustion engine is started, it acts as a generator, providing continuous electrical power to the vehicle, as shown in the diagram.

Parallel transmission drive unit

In the BYD Qin's transmission drive unit, there is a DCT dual-clutch transmission and a drive motor, which are paralleled by a reduction mechanism.

As shown in the diagram, the internal connections are:

The drive motor is connected to the gear transmission via a separate set of reduction mechanisms.

The internal combustion engine is connected to the gear transmission via a DCT dual-clutch transmission and a separate set of reduction mechanisms.

The BYD Qin's electric motor, which consists of a stator with an outer ring and a rotor with an inner ring, is one of the car's power sources, outputting torque outward to drive the car forward and backward; it can also be used as a generator to generate electricity (for example, during coasting, braking, and the potential or kinetic energy of the engine's output of extra torque is converted into electricity for storage through the electric motor).

The motor is an AC permanent magnet synchronous motor with a rated power of 40kW.