Engines deliver best fuel economy when operated in the low- and mid-speed segments of the efficiency range and produce maximum horsepower at rated speed, which is also the recommended maximum speed of the engine. 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. 1. It is seldom necessary to accelerate the engine to governed speed in the lower gears to get the ve- hicle moving, except in a high power demand situa- tion such as starting on a grade.
Detroit Diesel To conserve fuel, start off in low gear and develop only the engine speed needed to get rolling. Then, increase engine speed gradually as upward gear shifting progresses. Individual driving habits can make a difference in the performance and economy of any engine. The recom- mendations below call attention to the techniques that can be employed to save fuel and extend the operating efficiency and life of a new Detroit Diesel engine for the longest possible time. As described by Detroit Diesel, this progressive shifting technique will get the vehicle up to the de- sired cruising speed while minimizing noise emis- sion and maximizing fuel economy.
A progressive shift pattern is illustrated in Fig. 4.2 . Engines with Detroit Diesel Electronic Control (DDEC) can be equipped with a variety of options designed to warn the operator of engine problems. The operator of a DDEC-equipped engine should know the extent of the warning system in order to bring the vehicle to a safe stop if the engine malfunctions. If the operator doesn’t understand how the system works, an engine shutdown could cause a safety hazard. NOTE: A momentary hesitation in throttle response will occur when a vehicle with a turbocharged en- gine is started on a grade. Do not disengage the clutch. The rpm will recover and the vehicle will accelerate up the grade.
All engines have an operating range in which the en- gine performs most efficiently. The operating range ex- tends from maximum torque rpm at the low end to en- gine rated speed at the high end. Detroit Diesel engines 4.13