| [ car ] in KIDS 글 쓴 이(By): hongsang (NSX) 날 짜 (Date): 1995년02월11일(토) 18시58분45초 KST 제 목(Title): Emission and power According to the basic thermodynamics, most power can be extracted at the EQ (equivalence ratio) of 1. However, at that point, the formation of NOx is also at the peak, which we do not want. Before the catalytic conveter was invented, auto companies tweaked the carbureter in favor of less emission, sacrificing power output. On the other hand, Honda came up with "staged combustion" for emission s low enough to pass the regulations without sacrificing much power. Then, the era of catalytic converter came, and carbureters were tweaked for power again since the conveter now took care of emission. Now, free air flow means more power from an engine. If that flow is to be restriced due to some device like curved intake or exhaust pipes, some power is lost. The catalytic conveter acts like one of the devices. So, generally speaking, the stricter the emission regulations, the less power we're going to get. What auto companies do to reduce emission is basicly lower fuel flow into the cylinder so that less combustion will produce less pollutants. I'm not sure of how emission test goes. But, i think a car which is new to be imported is run for a period of time (or for a given distance ?), and the pollutants are measured in ppm. I'll try to find out how they do it. I remember seeing some kind of documentary film about how hyundai started exporting cars here in US. According to the film (actually, a TV series), hyundai barely passed the test on the second trial. |