GUARD ASSEM. 9G9785 - Caterpillar

Turbocharger
Illustration 2 g03823382
Typical Example
(1) Air Inlet
(2) Exhaust Outlet
(3) Exhaust Inlet
(4) Compressor Housing
(5) Compressor Wheel
(6) Bearing
(7) Oil Inlet Port
(8) Bearing
(9) Water-Cooled Turbine
(10) Turbine Wheel
(11) Oil Outlet PortAll of the air that enters the engine passes through the turbocharger. All of the exhaust gases from the engine pass through the turbocharger.The exhaust gases enter water-cooled turbine housing (9) through exhaust inlet (3). The housing of the turbochargers turbine is water cooled. This prevents the heat of the exhaust gases from radiating into the environment that surrounds the engine. The exhaust gas pushes the blades of the turbine wheel (10). The turbine wheel is connected by a shaft to the compressor wheel (5).Air that passes through the air filters enters the compressor housing air inlet (1) by the rotation of compressor wheel (5). The compressor wheel causes the inlet air to be pushed into the inlet side of the engine. Boost pressure is caused when the compressor wheel pushes more air into the inlet side of the engine. This results in a positive inlet manifold pressure that exceeds atmospheric pressure. This allows the engine to burn more fuel. When the engine burns more fuel, the engine produces more power.When the throttle is opened, more fuel is injected into the cylinders. The combustion of this additional fuel produces greater exhaust temperature. The additional exhaust temperature causes the turbine and the compressor wheels of the turbocharger to turn faster. As the compressor wheel turns faster, more air is forced into the cylinders. The increased flow of air gives the engine more power by allowing the engine to burn the additional fuel with greater efficiency.Bearings (6) and (8) for the turbocharger use engine oil under pressure for lubrication and cooling. The oil comes in through oil inlet port (7). The oil then goes through passages in the center section in order to lubricate the bearings. This oil also cools the bearings. Oil from the turbocharger goes out through oil outlet port (11) in the bottom of the center section. The oil then goes back to the engine oil pan.Crankcase Breather
The engine crankcase breather is a filtered system. The crankcase breather system consists of two main elements, a primary separator in the valve mechanism cover and a filtered canister that is mounted on the side of the engine. The gases exit the engine through the valve mechanism cover. The gases then pass through the primary separator. The primary separator removes most of the liquid oil from the gas. The liquid oil is then returned to the engine.The gas then passes through the filter element before exiting to atmosphere in an open breather system or back to the induction system in a closed breather system via the breather vent pipe.Any liquid oil that is captured by the filter drains from the bottom of the canister. The liquid oil is returned by the drain pipe that runs from the bottom of the canister back to the crankcase. A valve connects the drain pipe to the crankcase. This valve