Multifuel Engine

an internal-combustion engine designed to operate on a variety of petroleum fuels, from gasoline to diesel fuel.

The first multifuel engines were developed in the 1930’s in Germany. They were based on a carburetor engine but had separate air and fuel supplies. The air was sucked into the cylinders, but the fuel was injected by a pump at a pressure of about 5 meganewtons per sq m (MN/m²), or 50 kilograms-force per sq cm (kgf/cm²). The engines were started on gasoline, using a carburetor that was cut out during normal operation. The mixture was ignited by an electrical ignition system. In the 1940’s multifuel engines based on automobile diesel engines were developed. The fuel was supplied by a pump at a pressure of about 21 MN/m² (210 kgf/cm²). When shifting from one fuel to another the supply from the pump was adjusted to give the same consumption of fuel by weight, thereby maintaining the same engine power.

The use of multifuel engines in motor vehicles and tractors greatly extends their fuel resources. Such engines have better fuel economy than carburetor engines but are inferior to diesels. Among their disadvantages are complexity of design and the need for careful monitoring of the fuel-supply system during operation. They are used extensively abroad, especially in the Federal Republic of Germany.