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.