Planned legislation in the united states governing diesel exhaust emissions will reduce the permissible level by a factor of six from that currently permitted. The author considers the approach adopted by a variety of manufacturers in the reduction of emission and noise, giving examples of the latest methods of electronic engine management. Development continues to give higher specific power, lower specific fuel consumption and better durability. Air-to air inter-cooling increases overall engine efficiency and can reduce fuel consumption by some seven per cent. Designs employing a v8 or v12 configuration, originally for military use in tanks can give a 1500 hp output for short bursts. Two-stage fuel injection is being used in some 2 litre van and car engines to reduce noise levels by up to 2 dba. Revised fuel-injection systems with higher injection pressures will be needed to keep particulates down. Unitised pump-injections are envisaged by some manufacturers although an overhead camshaft could require more height. Timing and fuel quantity is controlled by electro-magnetic actuators under microprocessor control. Electronic throttle control, integral speed control and traction control were all options now being considered.
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