Most hybrid cars can automatically switch between the two drive systems, or have them run together. It depends on the driving situation. For example, when the car is driving at a constant high speed, the ECU switches to the internal combustion engine mode. At this point, the internal combustion engine operates particularly efficiently.
For example, when driving or overtaking on a slope, the two drive systems can operate in combination. In this case, it is necessary to use a power booster in a short time, and the motor can effectively supplement the power of the internal combustion engine.
In many hybrid cars, the motor itself drives the vehicle, in this case without consuming fuel. Because the motor has high efficiency even at low speeds, it is especially suitable for starting and running at low speeds.
A typical driving situation for a car with a parallel hybrid configuration (see below) is as follows: When the car starts, only the motor is running. As the car accelerates, the internal combustion engine starts. It usually operates on highways. If the driver hits the brakes or lets the car glide, the kinetic energy is captured and stored in the battery, which is then fed to the motor when needed.