2. Variable valve timing (VVTi, Vtec etc), direct injection technology (Dicor, CRDe etc).
3. More efficient transmissions by adding gears, modifying gear ratios and torque converters to yield maximum benefits.
4. Hybrid cars. Mahindra's Scorpio Hybrid is around the corner, while Honda's Civic Hybrid is waiting for it's wraps to be removed.
There are several ways to address this problem and one way that's slowly being adopted is by reducing the load on the engine- By making lighter cars.
That by far is the easiest way you can reduce fuel consumption.
Sounds simple doesn't it? A 1000 kg car consumes far less fuel than a 2500 kg car just like an elephant consumes less food than a dog.
By reducing the weight, the benefits can be reaped on the long run. A lighter car is faster, stops quicker and handles better.
It is a lot harder to make lighter cars than the conventional we discussed in the beginning. If you are trying to make a vehicle more fuel efficient from a transmission's stand point, you add new technology to the it. Or even an engine for that matter, you take an existing engine and put in variable valve timing or a variable geometry turbocharger.
If you have to make a car lighter, the entire car has to be redesigned. A switch in materials used means it needs to be different all together. Aluminium or Carbon fiber, which is adopted by most car manufacturers are lighter and stronger than conventional Steel. On the other hand, the cost factor plays a big role, both of those materials cost several times that of Steel.
But if you do go ahead and make the car with those materials, what you gain is substantial. You will end up with a car that is 20 to 30 % lighter, and 20 to 30 % more fuel efficient.
The trend of using lighter materials in everyday cars is setting in, and maybe 10 to 15 years from now, the Indica or the Alto will be dressed in these materials.