Petrol and diesel engines are highly efficient, but they come at a price. They emit CO2 and other gases and particles that pollute the atmosphere and might influence longer–term climate patterns. Toyota is therefore committed to developing technologies that reduce emissions to much lower levels.
Since petrol and diesel engines will probably continue to form the major source of automotive power for a decade, a major effort is being made to reduce the environmental impact of these technologies.
For example, Toyota has re–examined the whole structure of the internal combustion engine to identify specific ways in which petrol and diesel engines can burn less fuel more efficiently, and so emit less CO2 and other unwanted gases.
This has led to the development of integrated intelligent technologies that use advanced solutions inside engines to improve the management of fuel and driving operations. One of these is Variable Valve Timing–intelligent (VVT–i), which uses less fuel than comparable petrol engines and emits less carbon dioxide, nitrogen oxides and hydrocarbons.
Another is Toyota's Common Rail Diesel technology (known as D–4D), which injects a precise amount of fuel directly into the combustion chamber to deliver more efficient combustion and better fuel economy. These both help reduce CO2 levels in exhaust emissions.
Toyota has also made significant advances in developing engines that are powered by alternative energy sources. One of the most promising approaches is to combine two different power sources in a single system to exploit the performance potential of both. This is known as hybrid technology, and forms one of the most promising development paths on Toyota's eco–car roadmap.