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1106 Perkins - Air Inlet and Exhaust System
Air inlet and exhaust system - (1) Exhaust manifold (2) Electronic unit
injector (3) Glow plug (4) Inlet manifold (5) Aftercooler core (6)
Exhaust outlet (7) Turbine side of turbocharger (8) Compressor side of
turbocharger (9) Air inlet from the air cleaner (10) Inlet valve (11)
Exhaust valve
The 1106 Perkins diesel engine 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, Turbocharger, Aftercooler, Inlet
manifold, Cylinder head, injectors and glow plugs, Valves and valve
system components, Piston and cylinder, Exhaust manifold.
Air is drawn in through the air cleaner into the air inlet of the
turbocharger (9) by the turbocharger compressor wheel (8). The air is
compressed and heated to about 150C (300F) before the air is forced to
the after cooler (5). As the air flows through the aftercooler the
temperature of the compressed air lowers to about 50C (120F). Cooling of
the inlet air increases combustion efficiency. Increased combustion
efficiency helps achieve the following benefits: Lower fuel consumption,
Increased horsepower output, Reduced particulate emission.
From the aftercooler, air is forced into the inlet manifold (4). Air
flow from the inlet manifold to the cylinders is controlled by inlet
valves (10). 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,
Exhaust. On the compression stroke, the piston moves back up the
cylinder and the inlet valves (10) close. The cool compressed air is
compressed further. This additional compression generates more heat.
If the cold starting system is operating, the glow plugs (3) will also
heat the air in the cylinder. Just before the piston reaches the 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. Exhaust gases from exhaust manifold (1) enter the turbine side
of the turbocharger in order to turn turbocharger turbine wheel (7). The
turbine wheel is connected to the shaft that drives the compressor
wheel. Exhaust gases from the turbocharger pass through exhaust outlet
(6), a silencer and an exhaust pipe.
Valve System Components
Valve system components - (1) Bridge (2) Rocker arm (3) Pushrod
(4) Lifter (5) Spring (6) Valve
The valve system components control the flow of inlet air into the
cylinders during 1106 Perkins 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
through an idler gear.
The camshaft must be timed to the crankshaft in order to get the correct
relation between the piston movement and the valve movement. The
camshaft has two camshaft lobes for each cylinder. The lobes operate
either a pair of inlet valves or a pair of exhaust valves. As the
camshaft turns, lobes on the camshaft cause the lifter (4) to move the
pushrod (3) up and down.
Upward movement of the pushrod against rocker arm (2) results in a
downward movement that acts on the valve bridge (1). This action opens a
pair of valves (6) which compresses the valve springs (5). When the
camshaft has rotated to the peak of the lobe, the valves are fully open.
When the camshaft rotates further, the two valve springs (5) under
compression start to expand. The valve stems are under tension of the
springs.
The stems are pushed upward in order to maintain contact with the valve
bridge (1). The continued rotation of the camshaft causes the rocker arm
(2), the pushrods (3) and the lifters (4) to move downward until the
lifter reaches the bottom of the lobe. The valves (6) are now closed.
The cycle is repeated for all the valves on each cylinder.
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