Features and Parameters

The ISL Road Speed Governor limits road speed with the reliability you have come to expect from all Cummins products. First, set your speed and specify required parameters.

Global Maximum Vehicle Speed
Although the Road Speed Governor will limit the maximum speed of the vehicle, it is possible for the limit to be exceeded due to the provision of additional speed rewards delivered by the Driver Reward feature. For instance, if the Road Speed Governor maximum vehicle speed is set at 65 MPH and the Driver Reward feature is providing the operator with an additional 3 MPH, the maximum vehicle speed that can be attained would be 68 MPH. The Global Maximum Vehicle Speed is the maximum speed the vehicle may attain, no matter what additional speed rewards the Driver Reward feature may be providing. This guarantees that a vehicle speed limit is never exceeded, especially when Driver Reward is reprogrammed often.

Accelerator Maximum Vehicle Speed
Specify the maximum speed the vehicle can operate while using the foot accelerator on level road. The range is between 30 and 120 mph.

Accelerator Lower Droop
During normal operation, as a vehicle negotiates a downhill grade, the fueling required by the Cummins ISL engine to maintain the set vehicle speed will progressively decrease. By slowing the reduction in fueling and allowing the vehicle speed to exceed the set Road Speed Governor speed limit by a small amount, the positive effects of momentum can be utilized in anticipation of the next up-hill grade. Accelerator Lower Droop refers to the increase in speed above the set vehicle speed that the vehicle may travel in downhill circumstances. The available Lower Droop range is between 0 and 3 MPH. Setting Lower Droop to 3 MPH will allow the vehicle to exceed the set vehicle speed by 3 MPH before limiting fueling and provide the maximum benefit that may be gained from vehicle momentum. Setting Lower Droop to 0 MPH will minimize the effects of momentum but will provide the best speed control during these circumstances.

Accelerator Upper Droop
During normal operation, as the vehicle climbs an uphill grade, the Cummins ISL Electronic Control Module (ECM) will provide progressively increasing fueling to the engine in order to maintain the set vehicle speed. Continued uphill climbing could eventually result in the maximum fueling rate being attained with little to no positive impact on vehicle speed. Accelerator Upper Droop can minimize fuel consumed in these circumstances by automatically reducing the set vehicle speed by between 0 and 3 MPH. The time the engine spends at maximum fueling is thus reduced and fuel economy positively influenced. Setting the Upper Droop to 3 MPH will provide the best fuel economy benefit, while setting it to 0 MPH will provide maximum performance in these circumstances.

Speed Increase (Driver Initiated Override Maximum Road Speed Delta)
The 'Speed Increase' parameter is the additional vehicle speed that is applied to the maximum RSG speed when the driver has activated the feature.

Override Distance (Driver Initiated Override Maximum Distance)
The 'Override Distance' parameter is the allowable distance that can be travelled with the additional speed. The reset distance is 400 km (248 miles), at which point the allowed distance is reset. So, you get 'Override Distance' number of miles of added speed every 248 miles (the 248 is not trimmable, but fixed in the calibration). After 248 miles have been travelled, the speed bonus is again available for 'Override Distance' of the next 248 miles.

Feature/Parameter

Range

Default

Global Maximum Vehicle Speed - Parameter

30 - 120 mph

120 mph

Accelerator Maximum Vehicle Speed - Parameter

30 - 120 mph

120 mph

Accelerator Lower Droop - Parameter

0 - 3 mph

2 mph

Accelerator Upper Droop - Parameter

0 - 3 mph

0 mph

Speed Increase (Driver Initiated Override Maximum Road Speed Delta) - Parameter

0 - 35 mph

6 mph

Override Distance (Driver Initiated Override Maximum Distance) - Parameter

0 - 124 miles

124 miles