DESIGN ASPECTS, ECONOMICS AND ENVIRONMENTAL IMPACT OF TURBOCHARGED TRUCK DIESEL ENGINES

The basic principles of turbocharging are briefly outlined. The six cylinder turbine engine is ideal since turbocharging can be split into two blocks of three cylinders each having a common manifold. The design of a turbocharged engine is a compromise between the increased thermal and mechanical loading of the engine and its increased specific power. The author explains the need for matching the engine and turbocharger, taking into account the decrease of efficiency at higher speeds. The beneficial effects and methods of producing charge air cooling are discussed. Some problem areas are identified. Exhaust braking remains the same although the increased engine power makes it more suitable for heavier loads. To counteract turbocharger lad and puff of smoke during acceleration the engine is provided with a boost dependent full load step. Reasons are given for the better fuel consumption of the turbocharged engine compared with naturally aspirated engines. They are also insensitive to ambient pressure. The noise is decreased by the shorter ignition delay period of the turbocharged engine. The turbine also has a levelling effect on the exhaust pulses lowering the noise. Turbochargers can also be used to reduce nitrous oxide emission. /TRRL/