Cummins

cen dm 07.06.004

Follow the directions in this manual and the Cummins Operation and Maintenance Manual for trouble-free, economical vehicle engine operation.

  1. Cummins diesel engines produce high horsepower and peak torque characteristics at lower rpm. Because of this, it is not necessary to keep the engine "wound up" to deliver the required horsepower at the wheels. These characteristics may also result in less shifting and make shifting at lower rpm (toward peak torque) more practical.
  2. Depending on the vehicle gearing, the posted speed limit can sometimes allow operation in either of the top two gears; however, for improved operating efficiency (fuel economy and engine life), operate in the top gear at reduced rpm rather than in the next lower gear at the maximum rpm.
  3. Drive at partial throttle whenever road conditions and speed requirements permit. This driving technique permits operating within the most economical power range of the engine
  4. When approaching a hill, open the throttle smoothly to start the upgrade at full power, then shift down as desired to maintain the maximum vehicle speed. The high torque of Cummins engines may permit topping some grades without shifting.
  5. Cummins engines are designed to operate over a wide speed range. More frequent shifting than necessary does not allow proper utilization of this flexibility. The driver who stays in top gear and uses the wider speed range will achieve the best fuel economy.
  6. The Cummins diesel engine is effective as a brake on downhill grades, but care must be used not to overspeed the engine going downhill. The governor has no control over engine speed when it is being pushed by the loaded vehicle.
    Never turn off the ignition switch while going downhill. With the engine still in gear, fuel pressure will build up against the shutdown valve, and may prevent it from opening when the ignition key is turned on.

    7. Caution: Do not allow the engine to exceed its governed speed, or serious engine damage could result.

  7. Use a combination of brakes and gears to keep the vehicle under control at all times and to keep the engine speed below the rated governed rpm.
Note:
Parent topic: Engine Operation—CAT, Cummins, DDE S60, M-B
Document Number: 0000118191
Manual Publication Date: 2024-05-13
Topic Publication Date: 2024-06-06