Quote:
Originally Posted by Mark E Smith
. . . I am nit picking this because this was going to be my thesis for my ME degree in 1979.
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This poses and interesting question, could a diesel be built that "Atkinsonized" the compression stroke with a greatly increased expansion cycle?
Today's diesels are rated from 14 to 20 to 1 compression ratios and typically that is also their expansion ratio. I am wondering if one could be built that had say at 28 to 50 expansion ratio but the same compression ratio?
The idea is to maximize the expansion ratio of a compression ignition engine to further reduce the exhaust gas temperature when the exhaust valve is opened. Actually this begs the question: What is the maximum ratio of an Atkinson cycle before other effects limit the effectiveness?
If we took our Prius engine and put a modified intake cam that added degrees to the intake open angle, we would expect to see a further reduction in ICE power output. But at a minimum, it might avoid the inefficient specific fuel combustion that occurs above 4,150 rpm (in the NHW11 engine.)
Bob Wilson