Forty years of electronic gasoline injection from Bosch

D-Jetronic from Bosch was the first electronically controlled gasoline injection system in the world to be installed into a series-production passenger car and will be celebrating its 40th anniversary later this year. D-Jetronic was first unveiled to the public in the VW 1600 LE/TLE at the 1967 International Motor Show (IAA) in Frankfurt, Germany.

"D-Jetronic laid the foundations for the modern injection technologies of the Bosch Group. Today, we still pursue the same objectives with these technologies as we did then: to reduce both fuel consumption and exhaust-gas emissions," explains Dr. Steffen Berns, executive vice president engineering for Gasoline Systems at Bosch.

D-Jetronic technology made it possible for engine developers to reduce both fuel consumption and pollutant emissions for the first time. The reason for developing D-Jetronic was a result of growing demand in Europe for more economical engines and the strict exhaust emission standards adopted in the United States.

When the ‘Clean Air Act’ was implemented by Californian State authorities in 1967, D-Jetronic represented the only means by which many vehicle models at the time could comply with the emissions legislation. By 1972, just five years after its introduction, 18 manufacturers were using the innovative Bosch technology in mass production.

Air quantity as a parameter for electronics
The electronic control device in D-Jetronic was able to regulate the amount of fuel injected into the combustion chamber by adjusting the time the fuel injectors remained open. Alongside engine temperature and speed, the quantity of air drawn in represented one of the most important parameters for the electronic control function. A pressure sensor helped to calculate the quantity of this air based on the intake-manifold pressure. The development of D-Jetronic was accompanied by the development of electric fuel pumps that ensure constant system pressure in the fuel injectors.

As the global market leader, Bosch currently manufactures 80 million gasoline fuel injectors annually, and Bosch has recently produced the one billionth fuel injector for a gasoline engine.

Contemporary development work on injection systems at Bosch still focuses on economical engines with low pollutant emission values. The latest developments include solenoid- or piezo-actuated valves that inject at pressures of up to 200 bar and that are used in modern passenger car engines with gasoline direct injection. These devices help lower fuel consumption by up to 15 percent as compared to conventional manifold injection systems.