In the 90s, the automotive community actively discussed exotic engines capable of running not on gasoline or diesel, but on used vegetable oil. The idea seemed almost fantastical: waste from restaurant fryers, of which tons accumulate in developed countries, could simply be poured into the tank and continue driving. The cars not only drove but also emitted a characteristic smell of fried food, turning waste disposal into an energy source.
Unlike many rumors and semi-legendary projects, the Elsbett engine actually existed and was mass-produced. It was originally developed specifically for pure vegetable oil, and it was later discovered that the engine could run on almost any liquid fuel — from diesel and gasoline to kerosene, biodiesel, and used frying oil. Nevertheless, the optimal option remained ordinary vegetable oil, and not necessarily rapeseed — sunflower oil was also suitable.
The key feature of the engine was that the oil was used not only as fuel but also as a cooling medium. The unit lacked the usual water or air cooling system, which radically distinguished it from most diesels. This solution simplified the design and allowed for more effective control of the thermal regime when working on viscous and non-standard types of fuel.
From an engineering point of view, the Elsbett engine was extremely unusual. It had three cylinders, and each piston had a deep recess into which direct fuel injection was carried out. Due to the special orientation of the jet, the oil was thoroughly mixed with air and ignited inside this chamber, without touching the cylinder walls. This reduced losses, improved combustion, and had a positive effect on resource and economy.
By the standards of the 80s, the indicators looked impressive. The engine was approximately 25% more economical than the most modern diesel engines of that time. With a working volume of 1.45 liters, it weighed about 140 kg, developed 95 hp at 4500 rpm, and provided a torque of 15–16 kgm at 3000 rpm. Among other features is a fuel injection pump built into the head and the complete absence of a cylinder block gasket.
It is not surprising that the development aroused interest in various countries, including the USSR. In the late 80s, the Elsbett engine was planned to be installed on the experimental car AZLK-2144 "Istra". During the 1990 eco-rally, this model competed out of the standings but demonstrated a record consumption — only 2.69 liters per 100 km. In the urban cycle, the car fit into about 6 liters, and on the highway — into 4–5 liters, shocking the public when it was refueled with ordinary vegetable oil from the store.
However, the project was unlucky with the time. The economic and political upheavals of the early 90s led to the closure of the development, the liquidation of AZLK, and the actual termination of experiments. "Istra" remained in a single copy, and the Elsbett engine was no longer used in Russia. The situation abroad was similar: the manufacturing company faced financial difficulties and eventually ceased to exist.
The creator of this unusual design was the German engineer Ludwig Elsbett, born in 1913 into a farmer's family. He went from being a mechanic of agricultural machinery to a specialist in aircraft engines, worked at the Junkers factory, and after the war founded his own company, Elsbett. His engines gained worldwide fame in 1977, and in 1993 Elsbett Mercedes won the first ecological tour of Europe. Later, the company also received the European Solar Prize, showing that Elsbett's ideas went far beyond just one engine.