QUIET AND CLEAN. INNOVATIONS IN ENGINE DESIGN TO SOLVE PROBLEMS POSED BY .PENDING NOISE AND POLLUTION LEGISLATION

The article briefly discusses problems posed by pending noise and pollution legislation. It also reviews innovations in engine design, made by Volvo, in order to comply with such legislation as well as increase fuel economy and engine power. Details are given of various solutions under investigation at Volvo. Electronic control of its bosch fuel injection equipment gives more precise control of engine speed and load, thus producing a cleaner burn engine. Use of unit injection also decreases pollution. Various ways of turbocharging engines provide means to increase fuel economy and engine power. Sequential turbocharging and variable geometry turbocharging allow better control over air power. Turbocompound engines, in which exhaust gas is recovered by a turbine which drive back at the crankshaft, could increase fuel savings by about 5%. New methods of engine insulation under investigation include steel crown insulated pistons, using an air gap to stop heat flow down into the piston skirt. Such pistons are capable of running at 50-100% degrees c higher than standard pistons, and could also produce noise reduction of 1 db. The possible use of ceramic linings is also being investigated. (TRRL)