Piston for motor vehicle air conditioning compressor - has valve lift limiting ring with insert to reduce dead volume

摘要

The compressor has a piston (1) reciprocating in a cylinder (4). The suction valve (7) is fixed in the crown of the piston and gas enters from the crankcase. The piston has an upstand ridge round the valve and a ring (8) is fixed at the outer end of this ridge. It meets the edge of the valve plate (7) as the valve opens and so limits the lift of the valve at high engine speeds. The discharge valve (15) is clamped between the cylinder head (3) and the cylinder (4). An insert (17) on its underside projects into the space above the suction valve inside the lift limiting ring (8) when the piston reaches TDC. This prevents the lift limiting arrangement from increasing the dead volume.