The Development of an Automotive Drive-By-Wire Throttle System as a Research Tool

This paper describes the development of a drive-by-wire throttle system as an automotive research tool. The microprocessor based controller samples engine speed and driver demand (via accelerator pedal position) and utilises look-up-tables to determine the throttle position as a function of both of these input parameters. The inclusion of engine speed as an input to the function facilitates infinite freedom in the design of the ‘demand map’ within the constraints of the engine's performance limits. The system scheme is described, including a novel safety circuit which disables the engine in the event of a system failure. The principle of calibration is described along with a quick technique of validating a new demand map design on a sophisticated DC chassis dynamometer. The importance of the ‘demand map’, especially in relation to driveability, is discussed along with the prospects for exploiting this technology in vehicle development and on production vehicles. The issue of safety is tackled and it is concluded that a drive-by-wire system could be made as safe as a conventional mechanical linkage. The work of this paper was commissioned by the Ford Motor Company.