General Information 4 UENR4490-01 Systems Operation Section General Information The crankshaft gear turns the idler gear which then turns the following gears: the camshaft gear i05934599 Introduction the accessory drive gear (if equipped) the fuel injection pump gear the water pump gear The 1204F-E44TA and 1204F-E44TTA diesel engines are electronically controlled. The 1204F- E44TA and 1204F-E44TTA engines have an Electronic Control Module (ECM) that receives signals from the fuel injection pump and other sensors in order to control the electronic unit injector. The fuel injection pump supplies fuel to the high- pressure manifold (Rail).
The high-pressure manifold (Rail) distributes fuel to the electronic unit injectors. The camshaft runs at half the rpm of the crankshaft. The fuel injection pump runs at the same rpm as the crankshaft. The fuel injection pump that is installed on the left side of the engine is gear-driven from the timing case. The fuel is transferred to the fuel injection pump by an external electric transfer pump. The electric transfer pump draws fuel across a suction strainer that supplies fuel to the primary fuel filter and the secondary fuel filter. The fuel then travels to the fuel injection pump.
A pressure regulator that is installed in the low-pressure fuel system controls the fuel pressure to the fuel injection pump. The pressure regulator regulates the fuel at an absolute pressure of 150 kPa (22 psi) when the engine is at idle speed. The four cylinders are arranged in-line. The cylinder head assembly has two inlet valves and two exhaust valves for each cylinder. The ports for the exhaust valves are on the right side of the cylinder head. The ports for the inlet valves are on the left side of the cylinder head. Each cylinder valve has a single valve spring. The fuel injection pump increases the fuel to a maximum pressure of 200 MPa (2900 psi).
The fuel injection pump delivers the fuel to the high-pressure manifold (Rail). The fuel injection pump is not serviceable. The engine uses speed sensors and the Electronic Control Module to control the engine speed. Each cylinder has a piston cooling jet that is installed in the cylinder block. The piston cooling jet sprays engine oil onto the inner surface of the piston in order to cool the piston. The pistons have a Quiescent or a Re-entrant combustion chamber in the top of the piston in order to achieve clean exhaust emissions. The piston pin is off-center in order to reduce the noise level. For the specifications of the 1204F engine, refer to the Specifications, “Engine Design”.
The pistons have two compression rings and an oil control ring. The groove for the top ring has a hard metal insert in order to reduce wear of the groove. The skirt has a layer of graphite in order to reduce the risk of seizure when the engine is new. The correct piston height is important in order to ensure that the piston does not contact the cylinder head. The correct piston height also ensures the efficient combustion of fuel which is necessary in order to conform to requirements for emissions. The following model views show a typical 1204F engine. Due to individual applications, your engine may appear different from the illustrations. The crankshaft has five main bearing journals.
End play is controlled by thrust washers which are located on both sides of the number 3 main bearing. The timing case is made of aluminum or cast iron. The timing gears are stamped with timing marks in order to ensure the correct assembly of the gears. When the number 1 piston is at the top center position of the compression stroke, the marked teeth on the idler gear will align with the marks that are on the fuel injection pump gear, the camshaft gear, and the gear on the crankshaft. There are no timing marks on the rear face of the timing case.