High-Pressure

Lubrication System-High-Pressure








Pressurized oil entering the turbocharger assembly is utilized to actuate the exhaust back-pressure warm-up system. The exhaust back pressure regulator controls the oil leaving the turbocharger to actuate the back pressure device during cold ambient temperatures. The oil drains back through the turbocharger mounting pedestal and back into the oil pan. The valve lifter oil gallery supplies pressurized oil to the valve tappets and to the piston cooling oil jets. Oil from-the valve tappets is routed upward to the cylinder head valve train through hollow push rods. Once in the cylinder head, the oil drains back to the oil pan through return ports at each end of the cylinder head.

During cold starts, the high-pressure oil pump receives oil from the left side valve lifter oil gallery possibly through the short circuit valve. Once the engine starts or during warm engine starts, the short circuit valve closes and the high-pressure oil pump receives filtered oil from the high-pressure oil pump reservoir. The high-pressure oil pump pumps the oil under extremely high pressures (2758 - 20,577 kPa) through the left and right side high-pressure supply hoses to the high-pressure oil rails (integral to the cylinder heads). Once in the oil rail, the oil is fed to the fuel injector bores through four oil feed galleries drilled and machined in the cylinder head. The high-pressure oil then actuates the fuel injectors. The IPR valve controls and maintains the high-pressure oil. The PCM uses the information from ICP sensor to adjust the pressure in the system.