The transportation sector is subjected to regulation on CO2 emissions and fuel efficiency, which coupled with high oil prices, make energy efficient vehicles attractive.In the context of conventional vehicles, energy efficient technologies introduced in the sector to meet these targets include turbocharging, cylinder deactivation and camless valves, the use of six-speed or higher transmission or continuous variable transmission as well as improved efficiency of air conditioning, tire efficiency, the use of lightweight materials and an aerodynamically designed vehicle:
Camless valves prevent energy losses from the camshaft in an internal combustion engine by using a camless engine where pneumatic driven actuators open the valve to open the camless engine. Continuous variable transmission can adjust the engine speed to provide optimal power for acceleration compared to traditional transmission with a gear set with a given number of ‘speeds’.
Cylinder deactivation at light load, in other words, less than full speed, forces the throttle valve to be opened more fully creating constant power allowing the engine to breathe easier.
Turbochargers can improve the fuel efficiency of vehicles with an internal combustion engine. A turbocharger allows more air to enter the engine by channelling engine exhaust gas into the turbo, where it spins a turbine wheel. This fast spinning wheel drives a compressor wheel, which sucks in a large amount of ambient air, compresses it and then passes it through a charge-air cooler compressing it further. The air enters the engine and enables the engine to burn fuel more efficiently. Therefore, smaller fuel efficient engines can have the same power as a larger engine. A turbocharger consumes around 40% less fuel in diesel engines and 20% in gasoline and results in fewer CO2 emissions.