Detroit Diesel DD15 Engine DESCRIPTION AND OPERATION OF ROCKER COVER AND RELATED PARTS The rocker cover (2) is made of an aluminum or plastic material and uses an elastomer seal (1)
which completely encloses the valve operating mechanism including the overhead camshafts, brake assemblies and the injector harness.
Detroit Diesel DD15 The engine uses a dual overhead camshaft and rocker shaft design. The intake and exhaust camshafts are timed to each other, through a geartrain, to the crankshaft. The camshaft housing houses the camshafts and valve train. It has internal oil passages to supply oil from the block to the camshaft and rocker bearings along with pressurized oil to the engine brake rockers via the engine brake solenoids through the exhaust shaft. The camshaft housing is made of aluminium material.
Detroit Diesel DD15 Engine service Manual The engine uses an integral engine brake. Engine braking is controlled electronically by the engine control system with an electric solenoid. When activated, the solenoid allows oil pressure to activate a piston on the exhaust rocker arm. Engine braking is accomplished with a single exhaust valve in each cylinder. The exhaust camshaft uses a separate engine brake-only lobe that allows for double valve activation for high efficiency braking. The exhaust valve is first operated toward the completion of the intake stroke, closed during the compression stroke and opened a second time when the compression stroke is completed. The engine brake system is enabled using the following components:
For EPA07 engines:
- Engine brake solenoid valve in front of engine applies low engine braking.
- Engine brake solenoid valve in rear of engine applies medium engine braking.
- For high, both front and rear solenoids are activated.
- Six exhaust rocker arms with actuator pistons.
- Six brake rocker arms which are actuated by the brake cam lobes.
- Exhaust camshaft has one brake cam lobe per cylinder.