A Detailed History of the Common Rail Injection System

Learn about how the diesel engines' long history was improved by the invention of the common rail injection system.

A Detailed History of the Common Rail Injection System
Photo by Olivier Cleynen / Wikimedia

The modern version of the common rail injection system that is used in diesel engines was invented in 1990. This invention was built on nearly a century of advancements to the diesel engine.

While not as influential as the invention of the diesel engine that it operates on, the common rail injection system has done a lot for diesel automobiles. Between its long history and continued use in nearly all diesel engines the common rail injection system is quite fascinating.

What led to the invention of the common rail injection system?

As mentioned above, there is a lot of history behind the common rail injection system (CR injection system). New inventions are not made in a vacuum. In fact, the history of the CR injection system goes back as far as the first World War.

In 1913, a British engineering company, Vickers Ltd., filed a patent for a mechanically operated CR injection system. This design was used in submarine engines but was incompatible with automobile diesel engines of the day.

The first instance where electricity was used to control aspects of the system was in the 1930s. This new design by Harry Kennedy and Brooks Walker used electromagnets to operate fuel valves. It was used by an American diesel company by the name of Atlas-Imperial in many of its diesel engines.

Many engines on boats and trains during this time used a modified CR injection system in their diesel engines.

These early examples led to early concepts of the modern CR injection system for automobiles in the 1960s. It started with a more advanced electromagnetic fuel injection valve invented by Robert Huber.

At the time, the Swiss scientist was working with the Societe des Procedes Modernes D’Injection who were driving these new developments. Unfortunately, their advances were not enough to make the CR injection system more efficient than the system of the day.

After a few failed attempts to integrate the system into commercial automobiles in the 80s, we get to the 90s when several attempts bore fruit.

Who invented and introduced the common rail injection system?

In the 1990s, the German company Robert Bosch GmbH and the Denso Corporation from Japan both introduced the modern common rail injection system to automobiles.

The Denso Corporation obtained the concept from Renault and managed to implement it commercially in 1995. This development was fueled by Masahiko Miyaki, Takashi Iwanaga, and Hideya Fujisawa who had their patent approved in 1988.

As for Robert Bosch GmbH, their common rail injection system was acquired from the Fiat group and Mario Ricco. In the early 1990s, Mario Ricco was researching advancements for the CR injection system with the Fiat group.

When the Fiat group hit hard financial times, they sold the concept and research to Robert Bosch GmbH. The German company continued to develop it until they integrated the concept into commercial automobiles in 1997.

Both of these common rail injection systems resemble modern injection systems in that they are operated with an electronic control unit (ECU). This is the defining aspect that separates the early versions from the modern.

In addition, these were the first common rail injection systems adjusted to work in an automotive.

Why did they develop the common rail injection system?

With how long it took the automotive industry to develop this technology it is easy to see that it was an involved effort. You may be wondering why they went to such lengths. Part of it is certainly due to competition and a desire to advance for advancement’s sake.

However, there was a bigger reason behind why these companies raced towards implementing the technology. That reason was the ever-increasing emission standards. The Clean Air Act of 1970 was amended in 1990 to be much more strict on motor vehicles.

Early versions of the CR injection system were not much more efficient than the tech of the day. When the Denso Corporation and Bosch introduced the system to automobiles it was much more efficient than previously.

Using this new system, the companies were able to meet the various emission standards for diesel engines. Engines with the new system were quieter, more efficient, and cleaner.

The proven increase in efficiency in addition to the emission standards drove many other manufacturers to adopt the common rail injection system.

What was the first car to adopt common rail injection as standard?

The first diesel vehicles to adopt the common rail injection system came from the Denso Corporation and Alfa Romeo. The Denso Corporation made the first production vehicle with the system while Alfa Romeo made the first passenger car.

The Denso Corporation released a version of their Hino Ranger with the CR injection system in 1995. This truck was part of the fourth generation of Hino Rangers that lasted from 1989 to 2002. It was branded as a Hino Rising Ranger.

Alfa Romeo, with parts supplied by Robert Bosch GmbH, released the Alfa Romeo 156 in 1997. This compact executive car was produced between 1997 and 2007. It was the 2.4 JTD diesel engine that was the first common rail engine to be used in a passenger vehicle.

How did the common rail injection system affect sales of diesel cars?

Since common rail injection systems were not the only development in the late 1980s and 1990s it is difficult to pinpoint changes as a direct result of the CR injection system. Not to mention the reduced tax levies on diesel in the EU during the time.

There was also the advent of direct injection methods–which are often used in conjunction with common rail systems–during this timeframe. This is another factor that impacted the sales of diesel cars.

However, the common rail injection system did contribute to a large increase in the sales of diesel cars. The improvements it brought to diesel engines made them highly desirable.

In 1995 the percentage of diesel cars in countries under the European Environmental Agency (EEA) was 14.2%. This increased to 33.2% by 2009.