Once installed, the Engine Compression Brake only becomes available to the driver when the cab mounted Engine Brake On/Off switch is set to ON. A second cab mounted switch is provided to control the braking power level when the Engine Compression Brake is activated.
The Engine Compression Brake feature has several options and programmable parameters which can be used to modify the operation of the Compression Brake in accordance with user requirements. These options can be enabled, and the parameters set, using Cummins PowerSpec.
Because the operational characteristics of the Engine Compression Brake change depending on the options that have been enabled, it is advisable for the driver to be fully aware of just how the Engine Compression Brake has been configured prior to operating the vehicle.
Using the Engine Compression Brake with No Additional Features Enabled
In the standard configuration, without any of the additional optional features enable, the Engine Compression Brake will engage automatically when the following conditions are met:
The cab mounted Engine Brake On/Off switch must be set to ON.
Clutch Pedal must be released
Service Brake Pedal must be released
Accelerator Pedal must be fully released
No active Vehicle Speed Sensor (VSS) fault
Cruise control must not be performing an AutoResume
PTO/Remote PTO feature must not be active
Vehicle speed must be greater than Engine Brake Minimum Vehicle Speed.
When all of these conditions are met under normal operating conditions, the Engine Compression Brake will engage automatically upon full release of the Accelerator Pedal, and will disengage when the Accelerator Pedal is pressed.
The braking power level is set by the driver using a second cab mounted switch. This switch has two positions which allows the driver to select "low" or "high" braking power level.
Using Engine Compression Brake with Cruise Control Activation Option Enabled
The Engine Brake Cruise Control Activation feature permits the Cruise Control feature, when in control of the engine, to automatically engage the Engine Compression Brake when the vehicle exceeds the maximum selected speed. Once the required speed is regained, the Engine Compression Brake will automatically deactivate, allowing normal engine operation. Since the driver does not need to apply the service brakes and then re-activate the Cruise Control feature, driver comfort is increased and the use of Cruise Control is encouraged.
With the Engine Compression Brake with Cruise Control Activation option enabled, Cruise Control initiated activation and deactivation of the Engine Compression Brake is modified by the Cruise Control Speed Delta for Minimum Engine Brake parameter .
The Cruise Control Speed Delta for Minimum Engine Brake parameter specifies the amount that the vehicle speed needs to increase above the selected maximum vehicle speed before the minimum level of available Engine Compression Brake is automatically activated.