Engine Operation 16 UENR0623-02 When the load on the engine increases, more fuel is injected into the cylinders. The combustion of this additional fuel produces more exhaust gases. The additional exhaust gases cause the turbine and the compressor wheels of the turbocharger to turn faster. As the compressor wheel turns faster, air is compressed to a higher pressure and more air is forced into the cylinders. The increased flow of air into the cylinders allows the fuel to be burnt with greater efficiency. The more efficient burning of fuel produces more power. Crankcase Breather NOTICE The crankcase breather gases are part of the en- gines measured emissions output.
Any tampering with the breather system could invalidate the engines emissions compliance. The crankcase breather has a centrifugal separator. The centrifugal separator has a special coating. Engine oil that has been separated from the breather gas is returned to the timing case. The crankcase breather is driven by the shaft of the fuel injection pump. A wastegate is installed on the turbine housing of the turbocharger. The wastegate is a valve that allows exhaust gas to bypass the turbine wheel of the turbocharger. The operation of the wastegate is dependent on the pressurized air (boost pressure) from the turbocharger compressor. The boost pressure acts on a diaphragm.
The diaphragm is spring loaded in the wastegate actuator which varies the amount of exhaust gas that flows into the turbine. A heated connection may be installed on the pipe for the crankcase breather. The purpose of the heated connection is to prevent the formation of ice in cold climates, that could lead to an obstruction of the pipe. Valve System Components The wastegate regulator (15) is controlled by the engine electronic control module (ECM). The ECM uses inputs from a number of engine sensors to determine the optimum boost pressure. This will achieve the best exhaust emissions and fuel consumption at any given engine operating condition.
The ECM controls the wastegate regulator, that regulates the boost pressure to the wastegate actuator. When high boost pressure is needed for the engine performance, a signal is sent from the ECM to the wastegate regulator. This causes high pressure in the inlet manifold to act on the diaphragm within the wastegate actuator (13). The actuating rod (14) acts upon the actuating lever to close the valve in the wastegate. When the valve in the wastegate is closed, more exhaust gas is able to pass over the turbine wheel. This results in an increase in the speed of the turbocharger.
When low boost pressure is needed for the engine performance, a signal is sent from the ECM to the wastegate regulator. This causes high pressure in the air inlet pipe (12) to act on the diaphragm within the wastegate actuator (13). The actuating rod (14) acts upon the actuating lever to open the valve in the wastegate. When the valve in the wastegate is opened, more exhaust gas from the engine is able to bypass the turbine wheel, resulting in a decrease in the speed of the turbocharger. Illustration 14 g02720989 Valve system components (1) Rocker arm (2) Pushrod (3) Lifter (4) Camshaft The shaft that connects the turbine to the compressor wheel rotates in bearings (4) and (6).
The bearings require oil under pressure for lubrication and cooling. The oil that flows to the lubricating oil inlet port (5) passes through the center of the turbocharger which retains the bearings. The oil exits the turbocharger from the lubricating oil outlet port (10) and returns to the oil pan. The valve system components control the flow of inlet air into the cylinders during engine operation. The valve system components also control the flow of exhaust gases out of the cylinders during engine operation. The crankshaft gear drives the camshaft gear. The camshaft must be timed to the crankshaft in order to get the correct relation between the piston movement and the valve movement.