Bosch produces 75 millionth diesel common rail system

Following the 75th anniversary of Bosch’s introduction of diesel systems in passenger cars, Bosch is celebrating the production of its 75 millionth common-rail system. This technology, first used in cars 14 years ago, marked the start of a new image for diesel.

In 1997, the share of diesel passenger cars sold in Western Europe was 22 percent. Today every second newly registered passenger car is a diesel.

Bosch is the world’s leading supplier of common-rail systems.

“Automobile diesel engines were previously seen as economical and robust, but noisy. The modern common-rail diesel is just as efficient and durable, but it is also quiet, powerful, and eco-friendly. Common-rail high-pressure injection, in conjunction with turbocharging, has revolutionized the diesel engine,” said Ross Sandercock, director, product management for Bosch.

As efficient as today’s automotive diesels are, continuous improvements by Bosch will make diesel engines even more efficient in the future. For instance, by 2015 diesel-powered compact cars are set to consume as much as 30 percent less fuel than they do currently. And the use of hybrid technology can bring fuel consumption down by as much as 40 percent.

The first customers for common-rail systems in 1997 were Alfa Romeo, for its 156 JTD model, and Mercedes, for the C220 CDI. Unit sales of common-rail systems grew rapidly in the following years. By 2001, three million Bosch common-rail systems were in use, by 2002 the figure had already grown to ten million, and by the start of 2009 it was 50 million.

In 2011 alone, Bosch produced some nine million common-rail systems, which were fitted in passenger cars, commercial vehicles, in the off-highway segment, and also in large diesel engines such as those found in ships.

The name “common rail” is a reference to the pressure accumulator from which fuel is injected at high pressure into the cylinders via the injectors connected to it. The possibility of multiple injections that this allows makes engines quieter and reduces fuel consumption, as well as cutting emissions of CO2 and other pollutants. The first generation of common-rail systems operates at a pressure of 1,350 bar (19,580 psi), but today’s CRS2 achieves up to 2,000 bar (29,007 psi), with some Bosch systems at 2,500 bar (36,259 psi).

Fuel is precisely metered by solenoid valves that allow up to eight single injections per power cycle. CRS2 can be used around the world in all passenger car classes as well as in light commercial vehicles and the off-highway segment. Bosch also offers CRS3 with piezo injectors for the most demanding applications. This makes it possible to meter the tiniest amounts of fuel even more precisely for pre- and post-injection, which serves to further reduce NOx emissions and make the engine operate even more quietly. In this system, the injection pressure is as high as 2,200 bar (31,905 psi).

The diesel engine is well equipped for the future. In conjunction with NOx exhaust gas treatment such as Bosch Denoxtronic, common-rail technology makes it possible to meet the strictest emissions regulations, including Tier 2 Bin 5 in the United States or Euro 6 in Europe from 2014.