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*To*: quattro@coimbra.ans.net (Quattro List)*Subject*: Piston acceleration (was interferance etc)*From*: Orin Eman <orin@wolfenet.com>*Date*: Sat, 24 Jan 1998 02:39:51 -0800 (PST)*Sender*: owner-quattro@coimbra.ans.net

Well, I pulled some references... According to the Bosch handbook, the inertia force is proportional to N^2 * (cos(alpha) + lambda * cos(2*alpha)) where N is RPM and alpha is crank angle (TDC is 0), lambda is stroke/(2*rod length). cos(x) is at a maximum (1) for x = 0 and minimum (-1) for x = 180 This gives acceleration proportional to N^2 * (1 + lambda) at TDC N^2 * (1 - lambda) at BDC The magnitude is greatest at TDC. This is also covered in Corky Bell's book in the first few pages. "Internal Combustion Engine Fndamentals" by John B Heywood has a formula for velocity and differentiating it for acceleration, I got: 2 * PI^2 * N^2 * stroke (1 +/- lambda) Seems consistent. It's notable that the force on the con rods increases with RPM squared, so think twice before removing those rev limiters... Orin.

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