2008年5月24日 星期六

BMW HPI 高精準缸內直噴科技

HPI 高精準缸內直噴科技

High Precision Injection, the innovative petrol direct injection system from BMW, makes the combustion process more efficient. The engine delivers greater performance and a significant reduction in fuel consumption.

High Precision Injection is part of BMW EfficientDynamics, BMW's package of innovations that unite dynamic performance and fuel efficiency.
The core element of High Precision Injection technology is the piezo injector positioned between the valves and the spark plug. Inside the injector are multiple layers of piezo crystals which expand instantly when electricity is passed through them.

This forces a dose of the fuel/air mix out the injector needle and through the outlet (which is no wider than a human hair) and into the combustion chamber under a pressure of 200 bar. The cone-shaped cloud, the size of a thumb nail, is precisely injected onto the spark and combusts with an excess of oxygen. In contrast to conventional injection systems, BMW's High Precision Injection requires very little fuel and eliminates the waste caused by unburned fuel being sprayed on the walls of the combustion chamber.

Thanks to the piezo injectors, fuel can injected in just 0.14 milliseconds, making it possible to introduce multiple injections of fuel within one single combustion process. The high-performance, flexible electronic control system adjusts the timing and dose of the injected fuel according to the engine power demand, operating temperature and cylinder pressure. This ensures that combustion is precisely controlled, extremely clean and outstandingly efficient combustion - in every driving situation.