Paper 3: Paper 4: Renault Engines for Light Cars

Abstract

The problem posed was the design of an engine having a taxable horsepower of 5 for a private car with rear wheel drive and weighing 700 kg when empty. It was also required that there be two main variants derived from this: an engine for a sports car and one with a larger cubic capacity for a utility vehicle. The paper describes how this problem was approached.

After a re-examination of why the four-stroke carburation engine is very popular, the number and arrangement of the cylinders in relation to the cooling is considered.

Apart from certain arrangements imposed by the fitting of the engine in the car, the simplest form of construction is that of the water-cooled engine with the cylinders in line. The cooling circuit is sealed.

The arguments enabling the stroke and bore to be decided upon, first within the limits of a given cubic capacity and then by removing this restriction, are then expounded. The conclusion is that the bore should be as small as possible compatible with the performance called for.

The following technological details of the engine, which has been designed with two possible cubic capacities—956 and 1100 cm³ by varying the bore, are then considered: design of the cylinder block with wet liners; piston, connecting rod, crankshaft assembly; arrangement of valves, camshaft, carburettor and manifold; engine sealing and filtration.