838557 Volvo.Penta Brace

Illustration 1 g06163107
Typical example of the air inlet and exhaust system
(1) Aftercooler core
(2) Air filter
(3) Clean Emissions Module (CEM)
(4) Turbocharger
(5) Wastegate actuator
(6) Exhaust gas valve (NRS)
(7) Exhaust cooler (NRS)
(8) Inlet gas throttle valveThe components of the air inlet and exhaust system control the quality of air and the amount of air that is available for combustion. The air inlet and exhaust system consists of the following components:
Air cleaner
Exhaust cooler (NRS)
Exhaust gas valve (NRS)
Inlet gas throttle valve
Turbocharger
Aftercooler
Inlet manifold
Cylinder head, injectors, and glow plugs
Valves and valve system components
Piston and cylinder
Exhaust manifold
Clean Emissions Module (CEM)Air is drawn in through the air cleaner into the air inlet of the turbocharger by the turbocharger compressor wheel. The air is compressed to a pressure of about 150 kPa (22 psi) and heated to about 120° C (248° F) before the air is forced to the aftercooler. As the air flows through the aftercooler the temperature of the compressed air lowers to about 55° C (131° F). Cooling of the inlet air assists the combustion efficiency of the engine. Increased combustion efficiency helps achieve the following benefits:
Lower fuel consumption
Increased power output
Reduced NOx emission
Reduced particulate emissionFrom the aftercooler, the air flows to the air inlet connection and then to the inlet gas throttle valve for the NOx Reduction System (NRS). A mixture of air and exhaust gas is then forced into the inlet manifold.Air flow from the inlet manifold to the cylinders is controlled by inlet valves. There are two inlet valves and two exhaust valves for each cylinder. The inlet valves open when the piston moves down on the intake stroke. When the inlet valves open, cooled compressed air from the inlet port is forced into the cylinder. The complete cycle consists of four strokes:
Inlet
Compression
Power
ExhaustOn the compression stroke, the piston moves back up the cylinder and the inlet valves close. The cool compressed air is compressed further. This additional compression generates more heat.Note: If the cold starting system is operating, the glow plugs will also heat the air in the cylinder.Just before the piston reaches the top center (TC) position, the ECM operates the electronic unit injector. Fuel is injected into the cylinder. The air/fuel mixture ignites. The ignition of the gases initiates the power stroke. Both the inlet and the exhaust valves are closed and the expanding gases force the piston downward toward the bottom center (BC) position.From the BC position, the piston moves upward. This initiates the exhaust stroke. The exhaust valves open. The exhaust gases are forced through the open exhaust valves into the exhaust manifold.
Illustration 2 g06163129
Typical example
The NOx Reduction System (NRS) operates with the transfer of the hot exhaust gas from the exhaust manifold to the exhaust gas valve (NRS) (6).As the electronically controlled valve (6) starts to open the flow of cooled exhaust gas from the exhaust cooler (7) mixes with the air flow from the charge air aftercooler. The mixing of the cooled exhaust gas and the air flow from the charge air aftercooler reduces the oxygen content of the gas mixture. This results in a lower combustion temperature, so decreases the production of NOx.As the demand for more cooled exhaust gas increases the electronically controlled valve opens further. The further opening of the valve increases the flow of cooled exhaust gas from the exhaust cooler. As the demand for cooled exhaust gas decreases, the electronically controlled valve closes. This decreases the flow of cooled exhaust gas from the exhaust cooler.The hot exhaust gas is cooled in the exhaust cooler (7). The cooled exhaust gas passes through the exhaust cooler (7) to the inlet manifold.The electronically controlled exhaust gas valve (6) and the inlet gas throttle valve (8) for the NOx Reduction System (NRS) are controlled by the ECM.In some instances, the engine will need to use the electronically controlled exhaust gas valve (6) and the inlet gas throttle valve (8) for the NOx Reduction System (NRS) to generate the required flow of exhaust gas.The inlet gas throttle valve (8) for the NOx Reduction System (NRS) works by reducing the pressure in the inlet manifold to draw through extra exhaust gas.Exhaust gases from the exhaust manifold enter the inlet of the turbocharger to turn the turbocharger turbine wheel. The turbine wheel is connected to a shaft that rotates. The exhaust gases pass from the turbocharger through the following components: exhaust outlet, Clean Emissions Module, and exhaust pipe.Turbocharger
Illustration 3 g00302786
Typical example of a cross section of a turbocharger
(1) Air intake
(2) Compressor housing
(3) Compressor wheel
(4) Bearing
(5) Oil inlet port
(6) Bearing
(7) Turbine housing
(8) Turbine wheel
(9) Exhaust outlet
(10) Oil outlet port
(11) Exhaust inletThe turbocharger is mounted on the outlet of the exhaust manifold. The exhaust gas from the exhaust manifold enters the exhaust inlet (11) and passes through