Positive Crankcase Ventilation
The crankcase ventilation system is used to consume crankcase vapors in the combustion process instead of venting vapors to the atmosphere. Fresh air from the intake system is supplied to the crankcase, mixed with blow-by gases and then passed through a calibrated orifice into the intake manifold. The primary control is through the positive crankcase ventilation (PCV) orifice which meters the flow at a rate depending on inlet vacuum. The PCV orifice is an integral part of the camshaft cover. If abnormal operating conditions occur, the system is designed to allow excessive amounts of blow-by gases to back flow through the crankcase vent into the intake system to be consumed by normal combustion.
The blow-by system is designed as a closed crankcase ventilation system (CCV) evacuating the combustion gas from the crankcase (8), separating the oil with an oil separator (1), regulating the pressure in the cylinder head cover (2) over an pressure regulation valve (3) and feed the cleaned gas through the cylinder head (7) into the intake manifold (6). The primary blow-by system leads the gas through a non-return valve (NRV) directly into the plenum; the secondary blow-by pipe assembly (4) routes the cleaned blow-by gas from the intake manifold to the air intake of the turbo charger (9). Deviations from recommended materials have to be indicated and agreed. The blow-by pipe assembly carries the ventilation gas and prevents a leakage or a back-flow of the blow-by gas. It incorporates a quick connector to the manifold, the non-return valve (5) and a quick connector to the turbo charger as well as brackets to hold the pipe assembly. A combined quick connector with a non-return valve (10) at the turbo charger is installed, also.