The paper endeavours to trace the development of the passenger car engine over the three decades, 1920 to 1950. Both American and European practices are reviewed. In particular, the relation of fuel quality to engine design is emphasised as an important factor. The gasoline truck engine is briefly referred to where there were differences from passenger car practice, but the introduction of the Diesel (compression ignition) truck engine and its widespread adoption in Europe is treated at greater length.
