Sorry to bomb the list with this answer but I'm only just reading the digest
from 1st April.
Marcus Tooze asks about advance curves - the reason for advance is as he
correctly suspects due to combustion time. It takes a finite time for the
fuel-air mixture to ignite. The optimum time for the ignition is for maximum
pressure to be acheived just as the cylinder is approaching TDC. Equating this
time to an angle, it can be seen that as engine speed increases the angle
required to will also increase while the actual time remains constant.
Andy
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Andy Ashworth
Lloyd's Register email: tcsaca@uk.co.lreg.aie
29, Wellesley Road Phone: +44 (0)81 681 4723
Croydon Fax: +44 (0)81 681 4839
CR0 2AJ
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