20441860 Volvo.Penta Screw

Illustration 1 g02349356
Air inlet and exhaust system
(1) Aftercooler core
(2) Air filter
(3) Air control valve for the aftertreatment regeneration device
(4) Aftertreatment regeneration device
(5) Diesel particulate filter and diesel oxidation catalyst
(6) Low-pressure turbocharger
(7) High-pressure turbocharger
(8) Wastegate actuator
(9) Exhaust cooler (NRS)
(10) Exhaust gas valve (NRS)
(11) Inlet gas throttle valve
(12) Wastegate regulator The 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 gas cooler (NRS)
Exhaust gas valve (NRS)
Turbochargers
Aftercooler
Inlet manifold
Cylinder head, injectors, and glow plugs
Valves and valve system components
Piston and cylinder
Exhaust manifold
Aftertreatment regeneration device
Diesel oxidation catalyst
Diesel particulate filter
Inlet gas throttle valveAir is drawn in through the air cleaner into the air inlet of the low-pressure turbocharger by the low-pressure turbocharger compressor wheel. The air is compressed to a pressure of about 150 kPa (22 psi) and heated to about 120° C (248° F). From the low-pressure turbocharger, the air passes to the high-pressure turbocharger. The air is compressed to a pressure of about 325 kPa (47 psi) and heated to about 240° C (464° 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 horsepower output
Reduced NOx emission
Reduced particulate emissionFrom the aftercooler, the air flows to the exhaust gas valve (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. The piston moving forward initiates the exhaust stroke. The exhaust valves open. The exhaust gases are forced through the open exhaust valves into the exhaust manifold.
Illustration 2 g02297554
Typical example
The NOx Reduction System (NRS) operates with the transfer of the hot exhaust gas from the exhaust manifold to the exhaust cooler. The hot exhaust gas is cooled in the exhaust cooler (9). The now cooled exhaust gas passes through the assembly of the exhaust gas valve to an electronic controlled valve (10). The electronically controlled valve is electronically actuated.The reed valves that are located in the exhaust gas valve (NRS) have two main functions. The first function is to prevent the reverse flow of charge air from the inlet side of the engine to the exhaust side of the engine. The second function of the reed valve is to obtain exhaust gas when the peak exhaust pressure is above the average inlet pressure.As the electronically controlled valve (10) starts to open the flow of cooled exhaust gas from the exhaust cooler (9) mixes with the air flow from the charge air intercooler. 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 electronically controlled exhaust gas valve and the inlet gas throttle valve (11) 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 (10) and the inlet gas throttle valve (11) for the NOx Reduction System (NRS) in order to generate the required flow of exhaust gas. The inlet gas throttle valve for the NOx Reduction System (NRS) works by reducing the pressure in the inlet manifold in order to draw through extra exhaust gas.Exhaust gases from the exhaust manifold enter the inlet of the high-pressure turbocharger in order to turn the high-pressure turbocharger turbine wheel. The turbine wheel is connected to a shaft that rotates. The exhaust gases travel from the high-pressure turbocharger through the duct on the turbine side into the turbine inlet of the low-pressure turbocharger in order to power the low-pressure turbocharger. The exhaust gases pass from the low-pressure turbocharger through the following components: exhaust outlet, Aftertreatment Regeneration Device (ARD), Diesel Oxidation Catalyst (DOC), Diesel Particulate Filter (DPF) and exhaust pipe.Turbochargers
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 inlet The high-pressure turbocharger is mounted on the outlet of the exhaust manifold. The low-pressure turbocharger is mounted on the side of the cylinder block. The exhaust gas from the exhaust manifold enters the exhaust inlet (11) and passes through the turbine housing (7) of the turbocharger. Energy from the exhaust gas causes the turbine wheel (8) to rotate. The turbine wheel is connected by a shaft to the compressor wheel (3).As the turbine wheel