0384044 JOHNSON GEARCASE & BEARING ASSEMBLY

Illustration 1 g01914641
Air inlet and exhaust system
(1) Air-to-air aftercooler (ATAAC)
(2) Exhaust manifold
(3) Turbocharger
(4) Air Cleaner
(5) Clean Emissions Module (CEM)
(6) NOx Reduction System (NRS) cooler
(7) NRS venturi
(8) NRS valve
(9) Exhaust balance valve solenoid
(10) Intake manifold
(11) Cylinder headThe engine has an electronic control system. The system controls the operation of the engine and the Clean Emissions Module (CEM). The CEM consists of the following components: Aftertreatment Regeneration Device (ARD), Diesel Particulate Filter (DPF) and a muffler.The system consists of the following components:
Engine Control Module (ECM)
Wiring
Sensors
ActuatorsSingle Turbocharger System
Inlet air is pulled through the air cleaner . The inlet air is then compressed and heated by the compressor wheel of turbocharger to about 150 °C (300 °F). The inlet air is then pushed through air-to-air aftercooler core and the inlet air is moved to the air inlet elbow. The temperature of the inlet air at air inlet elbow is about 43 °C (110 °F). Cooling of the inlet air increases the combustion efficiency. Increased combustion efficiency helps to lower fuel consumption. Also, increased combustion efficiency helps to increase horsepower output.Aftercooler core is a separate cooler core. The aftercooler core is installed in front of the core of the engine radiator. Air that is ambient temperature is moved across the aftercooler core by the engine fan. This action cools the turbocharged inlet air.From aftercooler core , the air is forced into the cylinder head to fill the inlet ports. Air flow from the inlet port into the cylinder is controlled by the inlet valves.
Illustration 2 g02327074
Air inlet and exhaust system
(12) NRS cooler
(13) Exhaust manifold
(14) Aftercooler
(15) Exhaust outlet from turbocharger
(16) Turbine side of turbocharger
(17) Compressor side of turbocharger
(18) Air inlet
(19) Inlet valve
(20) Exhaust valveExhaust gases from the exhaust manifold enter the turbine side of turbocharger to turn the turbine wheel. The turbine wheel is connected to a shaft which drives the compressor wheel. Exhaust gases from the turbocharger pass through the exhaust outlet pipe, the muffler, and the exhaust stack.There are two inlet valves and two exhaust valves for each cylinder. Inlet valves open when the piston moves down on the inlet stroke. When the inlet valves open, cooled compressed air from the inlet port is pulled into the cylinder. The inlet valves close and the piston begin to move up on the compression stroke. The air in the cylinder is compressed. When the piston is near the top of the compression stroke, fuel is injected into the cylinder. The fuel mixes with the air and combustion starts. During the power stroke, the combustion force pushes the piston downward. After the power stroke is complete, the piston moves upward. This upward movement is the exhaust stroke. During the exhaust stroke, the exhaust valves open, and the exhaust gases are pushed through the exhaust port into the exhaust manifold. After the piston completes the exhaust stroke, the exhaust valves close and the cycle start again. The complete cycle consists of four stages:
Inlet stroke
Compression stroke
Power stroke
Exhaust strokeSeries Turbocharger System
Illustration 3 g01945084
Two turbochargers are arranged in a series on some C18 applications.
(A) To the aftercooler
(B) From the actuator on the balance valve
(C) To the Clean Emissions Module
(D) From the air filterThe low-pressure turbocharger compressor wheel pulls the inlet air through the air cleaner and into the air inlet. The air is compressed by the low-pressure turbocharger. Pressurizing the inlet air causes the air to heat up. The pressurized air exits the low-pressure turbocharger through the outlet and the air is forced into the inlet of the high-pressure turbocharger.The high-pressure turbocharger is used to compress the air to a higher pressure. This increase in pressure continues to cause the temperature of the inlet air to increase. As the air is compressed, the air is forced through the outlet of the high-pressure turbocharger and into the air lines to the precooler.The pressurized inlet air is cooled by the precooler prior to being sent to the aftercooler. The precooler uses engine coolant to cool the air. Without the precooler, the inlet air would be too hot to be cooled sufficiently by the aftercooler. The inlet air then enters aftercooler core. The inlet air is cooled further by transferring heat to the ambient air. The combustion efficiency increases as the temperature of the inlet air decreases. Combustion efficiency helps to provide increased fuel efficiency and increased horsepower output.NOx Reduction System (NRS)
The NRS sends hot exhaust gas from the exhaust manifold that is connected to cylinders one, two, and three through the NRS system. In order for exhaust gas to be able to mix with pressurized air from the ATAAC, back pressure is needed in the exhaust system. This back pressure is created by the turbocharger and DPF. The hot exhaust gas is first cooled in the NRS cooler. The now cooled exhaust gas passes through the NRS venturi. The venturi takes a measurement of the flow of exhaust gas through the NRS system. After the gas flow is measured by the NRS venturi, the gas flows through the electronically controlled NRS valve. The electronic controlled NRS valve is hydraulically actuated. When the NRS valve is in the full OFF position, the only source of air for the engine is from the turbocharger compressor. As the valve starts to open the flow of cooled exhaust gas from the NRS cooler mixes with the air flow from the turbocharger. As the demand for more cooled exhaust gas increases, the valve opens wider. This widening increases the flow of cooled exhaust gas from the NRS cooler. As the demand for more cooled exhaust gas increases, the demand for air flow from the turbocharger decreases.Turbocharger
Illustration 4 g02213856
Turbocharger
(21) Air inlet
(22) Compressor housing
(23) Compressor wheel
(24) Bearing
(25) Oil inlet port
(26) Bearing
(27) Turbine housing
(28) Small path
(29) Balance valve chamber
(30) Large Path
(31) Turbine wheel
(32) Exhaust outlet
(33) Oil outlet portThe turbocharger is installed on the exhaust manifold. Most of the exhaust gases flow through the turbocharger. A metered amount of exhaust gases flow through the NRS system. The compressor side of the turbocharger is connected to the aftercooler by a pipe.The exhaust gases go into