Workshop Manual

2.1 DESCRIPTION AND OPERATION OF CAMSHAFT AND ROCKER SHAFT/ENGINE BRAKE ASSEMBLY

AND RELATED PARTS

2.1.1 Engine Braking

The engine uses an integral engine brake. Engine braking is controlled electronica

llybythe

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 l

ow engine braking.

□ Engine brake solenoid valve in rear of engine applies m edium engine braking.

□ For high, both front and r ear 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.

All information subject to change without notice.