Hybrid cars and conventional cars share a lot of the same components. This is because a hybrid car is actually a conventional car with a hybrid package, or system added to it. The type of hybrid system added to the car can vary widely from a simple system to a complex system depending on how the manufacturer designs the system.
The electric portion of a hybrid vehicle consists of at least three major components: the motor generator, the high voltage battery and an electronic controller.
A very simple system from one manufacturer consists of a large motor/generator mounted on the engine at its normal position and driven by a heavy duty belt system. An electronic controller, a high-voltage battery pack, electric power steering, and an additional electric pump in the automatic transmission, round out the system. As this vehicle comes to a stop the generator will store braking energy in the battery pack. The electronic controller will allow the engine to stop running, while the vehicle is stopped, to save additional fuel. When the driver releases the brake and steps on the accelerator, the controller will direct the motor generator to restart the engine automatically and assist in acceleration. Another variation of this simple system mounts the motor generator in between the engine and the transmission or inside of the transmission, which would eliminate the need for the heavy-duty belt drive system.
Both of these systems allow regenerative braking, as well as auto engine stop and start and acceleration assist. These systems do not allow electric only operation, the engine must be running for the vehicle to move.
A more complex system uses a very high capacity battery pack, along with multiple motor generators that allow electric only drive. These vehicles can be driven on electric power only without the engine running, for short distances.
The ability of a hybrid vehicles engine to stop running when the car stops is a great benefit to fuel savings and lower emission levels. It presents a problem, however, because many of the vehicle’s accessories derive their power directly from the running engine. If we allow the engine to stop turning we have to find a new method to power those systems while the engine is at rest. This is usually accomplished with the addition of an electric motor, or pump for hydraulic systems, or a complete redesign of the system.
The braking system has received considerable redesign to meet changing needs of a hybrid vehicle. Not only do we need to maintain a power supply to the brakes when the engine is not running, but a decision needs to be made as to when to switch over from regenerative braking to normal friction brakes. This vehicle is it decreases, the point is reached at which the rate of regeneration is no longer efficient and friction brakes must be applied to stop the vehicle. In a panic stop situation friction brakes produce all of the braking force for the quickest stop possible.
There are two separate electrical systems, hybrid vehicle. There is a conventional 12 Volt direct current system, which operates all of the accessories such as the headlights the wipers, the horn, the radio, the heater and others. The hybrid system is a very high-voltage alternating current system, which commands respect. They are dangerous systems, and it is not difficult to get hurt or possibly even killed when working around them. The lowest voltage hybrid systems are approximately 42 Volt systems that utilize 36 Volt batteries. Some systems approach 400 Volts during operation and utilize 350 Volt batteries. The cables that connect the high-voltage components on the 42 Volt systems are colored blue, while the higher voltage systems are colored bright orange. Stay away from the colored cables!
ASE Master, L1, L2, Hybrid Certified Technician