When it comes to economical cars it is not difficult to build them with conventional internal combustion engines. Most cars of this type are equipped with three cylinder direct online petrol engines. The traditional four cylinders or the six cylinders are not used. If at all, they are being used they are equipped with the possibility of shutting down one or two cylinders when it is possible.
In order to make gasoline engines more efficient, car manufacturers use more advanced technologies. One of the technologies that are being used for increasing the efficiency or gasoline engines is the direct fuel injection. The efficiency is enhanced further by employing electronic systems to control fuel injection. Engines with variable valve timing also are better on fuel efficiency. As the timing of valves depends on the engine speed the variable timing of valves is a good option for saving fuel.
Using hybrid engines in cars is also one of the most proven ways of saving fuel. This is of special importance if you drive more on city roads where there is heavy traffic. The engine powers the car when it is driven at high speeds but when it comes to a halt on a traffic light, the computer will shut down the engine saving fuel. Also when acceleration is not necessary at slow speeds, the electric motor will take over the job of providing the power to drive the car.
When you apply brakes, the energy is wasted in a conventional car by way of heat. But with the hybrids the energy produced is used for charging batteries. This regenerative power will keep on charging the batteries whenever you apply brakes.
When hybrid cars are running on the electric motor they are almost 90% efficient. This is because there is no energy loss with electric motors. In contrast, the most economical gasoline engine is only 25% efficient. When it comes to an efficient small diesel engine its efficiency is only around 40%.
Diesel engines also could be used economically to save fuel. Lots of small cars use these engines to provide better fuel economy. Most of them use turbo chargers to pump air into the engine. When the air is pumped into the engine the engines they could run more efficiently. Some diesel engines have fuel pumps that are driven by the engine. Since these pumps are able to pump diesel at high pressure, the engines achieve high degree of efficiency.
