It should be noted that, in series hybrid vehicles, the petrol engine turns a generator, and the generator can either charge the batteries or power an electric motor that drives the transmission.
Thus, the petrol engine never directly powers the vehicle. In this category of vehicles, the purpose of the petrol engine is just to provide an inbuilt “battery charging” device.
Examining the series hybrid, starting with the fuel tank, you can easily notice that all of the components form a line that eventually connects with the transmission. The hybrid car joins two sources of power to increase efficiency and provide the kind of concept most people would be yearning for in a vehicle.
That said and done, how does the Hybrid perform? The key to a hybrid car is that the petrol engine can be much smaller than the one in a conventional car and therefore more efficient.
Most cars require a relatively big engine to produce enough power to accelerate the car quickly. In a small engine, however, the efficiency can be improved by using smaller, lighter parts, by reducing the number of cylinders and by operating the engine closer to its maximum load.
When you come to think about it, there are some reasons why smaller engines can be more efficient than bigger ones; the big engine is heavier than the small engine, so the car uses extra energy every time it accelerates or drives up a hill.
The pistons and other internal components are heavier, requiring more energy each time they go up and down in the cylinder.
The displacement of the cylinders is larger, so more fuel is required by each cylinder. Bigger engines usually have more cylinders, and each cylinder uses fuel every time the engine fires, even if the car static.
We could base on the above to explain why two of the same model cars with different engines can get different mileage. If both cars are driving along the highway at the same speed, the one with the smaller engine uses less energy.
Both engines have to output the same amount of power to drive the car, but the small engine uses less power to drive itself. But how can this smaller engine provide the power your car needs to keep up with the more powerful cars on the road? Take an example of a Land Cruiser Lexus, with a huge V-8 engine, to a hybrid car with its small petrol engine and an electric motor.
The engine in the Lexus has more than enough power to handle any driving situation.
The engine in the hybrid car is powerful enough to move the car along on the freeway, but when it needs to get the car moving in a hurry, or go up a steep hill, it may need extra assistance.
That “extra assistance” can come from the electric motor and battery this system steps in to provide the necessary extra power. When there is no need for the extra power, it is turned off, yet the Lexus keeps running on excess power!
The petrol engine on a conventional car is sized for the maximum power requirement (e.g. those few times when you would press hard on the accelerator pedal). In fact, most drivers rarely use this power, if they do; it is less than one percent of the time. The hybrid car uses a much smaller engine, one that is sized closer to the average power requirement than to the peak power.
The major theory in a hybrid car is that the petrol engine can be much smaller than the one in a conventional car and therefore more efficient. Most cars require a relatively big engine to produce enough power to accelerate the car quickly.
In a small engine, however, the efficiency can be improved by using smaller, lighter parts, by reducing the number of cylinders and by operating the engine closer to its maximum load.