Larry, could you please explain why the carbon produced during the combustion of diesel fuel (soot) is any less abrasive than that produced by a gasoline engine? Is it a different form of carbon? (Such as graphite, which we all know is not exactly an abrasive.) Or perhaps it is due to particulate size? Just curious.

Also, FYI, you stated that “in a diesel engine, you typically do not burn valves and other ills that happen to a gas engine upon leaning out for some reason”.

The reason is that leaning out the mix in a gasoline engine increases the combustion temperature significantly, but only up to the point of a misfire condition. A diesel is inherently running lean (except under full load?) due to the lack of throttling. The lack of throttling is also a source of increased efficiency due to the lack of pumping losses. This is why there is so much interest in gasoline direct injection. The unfortunate part of GDI *is* it’s lean running condition which produces too much NOx.

Thanks.