A truck engine has variable valve timing on its intake valves. The exhaust valves open at 31° bBDC and close 20° aTDC at all engine speeds. It is desired to have 0.004 seconds of valve overlap at 3000...

A truck engine has variable valve timing on its intake valves. The exhaust valves open at 31° bBDC and close 20° aTDC at all engine speeds. It is desired to have 0.004 seconds of valve overlap at 3000 RPM and 0.002 seconds of valve overlap at 1200 RPM.

Calculate:

(a) Crank angle when intake valve should open at 3000 RPM. [° bTDC]

(b) Crank angle when intake valve should open at 1200 RPM. [° bTDC]