Nelson and I were having a discussion off the list about valves. I said I
would investigate why the exhaust valve is smaller than the intake. I
discussed this with a colleague who is a powertrain engineer.
There is a limited amount of space for the valves. You want to make the
intake valve as large so more air and fuel can flow in.
The exhaust valve opens with high pressure from combustion gasses behind it.
Because of this gas can flow out of a given area at a higher rate, or the
area can be smaller to get the same flow.
Since the exhaust valve can be smaller, it is made smaller leaving room for
a larger intake valve.
Excuse me if this is common knowledge. Thought I'd share it anyway.
- Hugh
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