Four stroke spark ignition engine with separate variable camshafts and method therefor

摘要

Four-stroke Otto engine comprises at least one camshaft for the inlet valves and at least one camshaft for the outlet valves. The camshafts have an adjusting device for phase displacement. The Otto engine is designed so that during late adjustment of the inlet camshafts it operates in an Atkinson cycle. An Independent claim is also included for a process for controlling the above four-stroke Otto engine. Preferred Features: The Otto engine is designed so that during late adjustment of the inlet valve camshafts the inlet valves are closed late, preferably at a crankshaft angle of about 60-80degrees after the lower dead point (TDC) of the piston.