Ever-tightening emissions requirements, teamed with consumers' lust for today's high horsepower numbers, have led to some creative valve timing and lift schemes. Infiniti's G37 will be pack some interesting tech underhood when it debuts at the upcoming New York International Auto Show. There are actually two new developments working i
Mechanically actuated valves may soon be a thing of the past. We've made over a century's worth of improvement on the same basic combination of a camshaft, followers (or lifters), a poppet valve and a spring. We've gone from using pushrods and rocker arms to actuate the valvetrain to direct-acting buckets motivated by an overhead camshaft with variable phasing and lift. While engineering ingenuity has managed to wring incredible performance and flexibility out of these setups, there's only so fa
One of the main hurdles facing diesel engineers is developing a real-time sensor to help the vehicle's on-board computer with fuel delivery timing. Through computer modeling and other research, engineers know there's a very small window in the combustion cycle that produces optimum power with hardly any harmful emissions. But this window of opportunity moves around depending on cylinder pressure.