ISG hybrid system
The ISG is an acronym for integrated generators with starter functions.
The main functions of the ISG hybrid system are idle start and stop, regenerative braking, auxiliary drive and power generation. The HCU (Hybrid Control Unit) controls the driver's request (the accelerator pedal depth), the state of the battery compartment energy storage unit (the amount of power that can be released), the state of the electric drive system (parking, driving), and the state of the vehicle. The working mode of the ISG motor automatically realizes the above functions.
The following is an example of a Mercedes-Benz 400 hybrid car. Mercedes-Benz 400 represents the high-end level of ISG hybrid, the main components shown in Figure 2-34: high-voltage lithium battery module, motor power module, electric motor composed of electric power assist system; DC / DC DC voltage conversion system; steering system adopted The HEPS hydraulic electric steering system; the power controller such as the motor controller and DC/DC adopts the design of the double electric cooling circulating pump; the braking system adopts the electric vacuum pump, the vacuum booster, the ABS control unit and the electric motor to realize the regenerative braking; The air conditioner uses an electrically controlled electric compressor.
The crankshaft speed and position signal of the engine adopts the outer rotor of the motor connected to the crankshaft of the engine as the signal wheel. The stator and rotor of the motor adopt the method of inner stator coil and outer rotor permanent magnet. The inner stator coil is supported by the stator bracket, and the outer permanent magnet rotor and The crankshaft position/speed signal wheel is connected, and the through hole on the inner hub of the signal wheel is connected to the rear end of the crankshaft of the engine.
The hybrid management system is responsible for coordinating the interactions between the various subsystem components. The management system is integrated in the ECU and communicates with system units such as automatic transmissions, batteries and power electronics via the CAN-bus.
Wherein, the power electronic device is responsible for managing the energy flow between the motor and the high-voltage battery, and in addition to controlling the pulse inverter of the motor, a DC transformer is also included, which can convert the current from the generator or the battery into 12V DC, thereby Support vehicle electrical system work.
The hybrid management system can automatically perform automatic analysis and select the ideal operating strategy based on the state of charge of the battery, vehicle speed and other specific parameters. This operating strategy is a key component of the drivetrain control software that can be connected to each system to optimize battery power usage to maximize efficiency and eliminate drag caused by engine drag. In high-speed and stable driving conditions (up to 160km/h), when the driver releases the throttle, the V6 engine will be completely disengaged from the automatic transmission under the control of the clutch device, avoiding unnecessary friction loss and increasing the vehicle sliding distance. Reduce fuel consumption.
Take the Touareg Hybrid as an example. When the vehicle is under 50km/h, when the motor is driven, the V6 engine is not just completely closed. The clutch device will completely separate the engine from the 8-speed automatic transmission. Once the driver steps on the accelerator pedal at this time, such as overtaking, accelerating, etc., the turbine will immediately restart smoothly and raise the speed to a level suitable for the current speed.
In addition, the energy recovery system converts the electric motor into a generator during braking and recovers and stores excess energy in the nickel-hydrogen battery pack. As part of the powertrain system, the Auto Start-Stop system also helps improve fuel economy in stop-and-go urban congestion.
