125 years of Bosch - Invented for life The diesel passenger car turns 75 Diesel engines offer high potential
Even in 20 years' time, diesel engines will remain one of the most important powertrain types in passenger cars. Bosch, one of the world's leading providers of diesel systems, has based its forecast on diesel engines' enormous development potential: fuel consumption and emissions will be cut further in the future. The developers at Bosch Diesel Systems are predicting fuel consumption of just 3.6 liters per 100 kilometers for a compact-class diesel-powered passenger car by 2015.The
1936 through 2011: 75 years of diesel innovations in passenger cars
In the 1930s, Daimler-Benz planned to expand to passenger cars its use of diesel engines that had Bosch injection. The world's first series-produced diesel passenger car, a Mercedes-Benz 260 D, celebrated its premiere at the Berlin Automobile Exhibition in 1936. It used a third less fuel than a gasoline model for the same power output. Sales were initially disappointing since the diesel car was no match for its gasoline-powered counterparts in terms of performance and smoothness. Nevertheless an important step had been taken, and diesel engines were to become increasingly important in passenger cars in the post-war period. By 1950, Bosch had manufactured one million diesel pumps for passenger cars and trucks. Thanks to their cost-effectiveness, diesel-powered passenger cars were growing in popularity, particularly as taxis, which had to withstand harsh driving conditions. At the time, Bosch was already focusing on systems competence and on supplying components precisely tuned to the injection pumps – components such as fuel supply pumps, fuel filters, injection nozzles, and glow plugs.
As early as 1960, Bosch unveiled the first distributor pump. It was lighter and more compact than existing in-line pumps, paving the way for the use of diesel engines in smaller passenger cars. The distributor-pump engineers at Bosch had identified a trend early on that was to become a veritable diesel boom in the mid-1970s. The phenomenon behind this boom was the VW Golf Diesel. In 1975 it became the first compact-class diesel model to have a high-speed diesel engine, which delivered high revs yet was economical at the same time thanks to the Bosch distributor type injection pump. With a turbocharger and lightning-fast looks, the Golf “GTD” version would achieve cult status as the first sporty diesel-powered passenger car. All the major manufacturers across Europe followed suit with “Golf-class” diesel models. The Bosch distributor pump, which was used in numerous high-volume models, underpinned this success.
The mid-1980s saw the dawn of the electronic era for diesel models. In 1986, Bosch launched the first electronic control systems for its distributor and in-line pumps. In 1987, Munich-based BMW became one of the first automakers to start using electronically controlled distributor pumps. “Sheer Driving Pleasure” was now possible with the first turbo diesel engine made by BMW, which was available in the six-cylinder 524 td – the world's fastest series-production diesel-powered passenger car of its day. In 1989, the first axial piston pump for diesel direct injection revolutionized the diesel engine. This innovation premiered in the Audi 100 TDI (Turbodiesel Direct Injection). The new Bosch technology allowed the diesel to be injected directly into the cylinder at a high pressure of some 1,000 bar, resulting in particularly efficient combustion. This meant much better power output and smoothness coupled with low fuel consumption and emissions. Direct injection was to become the norm a few years later in diesel passenger-car and truck engines. In the late 1990s, the uptake of diesel engines received a major boost with the development of another three different high-pressure injection products: the radial piston distributor pump (1996), the common rail system (1997), and the unit injector (1998), which was used in vehicles such as Volkswagen's three-liter Lupo.
Common rail: 21st-century injection technology
Of all the alternatives available in the late 1990s, common rail injection technology ultimately established itself as the leading solution. Bosch produced the one millionth system just a year after launching common rail, and reached the three-million mark in 2000. Starting in 1997, the Mercedes-Benz 220 CDI and the Alfa Romeo 156 JTD became the first cars to use the innovation. It provided constantly high injection pressures of up to 1,350 bar for all the cylinders served by the common rail. The common rail system made multiple injections possible for the first time. In 2003, Bosch unveiled the third generation of common rail injection featuring piezoelectric in-line injectors. Compared with its predecessors, this system further reduced the diesel engine's fuel consumption and exhaust emissions, while also reducing the associated running noise. In 2005, the German Federal President awarded Bosch experts the German Future Prize for their product. Over 66 million engines have been fitted with Bosch's common rail systems to date.
The diesel engine – every second counts
The leading European automakers all caught the diesel wave in the mid-1970s and began to offer diesel power units in series-production vehicles. Various diesel prototypes were designed to demonstrate the everyday practicality of the diesel engine. Opel broke 20 international and two absolute world records for cars in all categories with its diesel-powered Opel GT test vehicle in 1972, and the diesel pioneer Mercedes caused a worldwide frenzy with the C111-III in 1978. Mercedes set nine world speed records in Nardo, Italy, with the eye-catching C111-III prototype achieving a top speed of 338 kph and an average speed of 325 kph. This success was based on the three-liter five-cylinder engine in the then new Mercedes-Benz 300 D. Almost 30 years later, Bosch common rail technology made diesel engines the preferred option in the Audi and Peugeot Le Mans racecars. Reliability and durability are just two valuable characteristics that have helped Audi and Bosch clinch overall victory on four occasions at this long-established competition. The decisive advantage of diesel engines is their far lower fuel consumption. In the world's most grueling long-distance race, this translates into longer stints at the wheel for drivers, fewer refueling stops and, in turn, a comfortable lead in lap times over gasoline-powered rivals.
The diesel engine – taking global markets by storm
Bosch common rail technology once again propelled the diesel boom at the start of the new millennium. While in 1997 only 22 percent of all passenger cars sold in western Europe ran on diesel, this figure was over 50 percent in 2006. Common rail technology still offers a great deal of technical potential: even the most stringent emissions limits in the U.S. state of California can be met using common rail. Over the past few years, several European, U.S., and Asian manufacturers have initiated a major diesel campaign in the United States. The two premium automakers Audi and BMW joined the ranks of Mercedes-Benz in increasingly opting for diesel engines in the U.S. Bosch expects that the proportion of diesel-powered engines will grow in the United States from 5 percent currently to some 10 percent in 2015. “Clean diesel” may become the preferred option even more quickly in Asia's emerging markets, since those countries' emissions targets can only be met by using high-pressure direct injection. Today, Bosch sells over one million common rail systems in India and China combined.
Better efficiency for economical, environmentally friendly diesel engines
Targets for reducing fuel consumption have been tightened substantially over the past few years, with the transition from the Euro 5 to Euro 6 emissions standard meaning that NOX emissions will need to be cut by more than half. To this end, Bosch engineers are increasing exhaust-gas recirculation rates, charge-air pressures for combustion air, and injection pressures over the greater part of the engine map, thus reducing nitric oxide levels in the combustion process. Bosch engineers are also applying exhaust-gas treatment to further improve diesel-engine efficiency: they have taken the Denoxtronic for SCR (Selective Catalytic Reduction) NOx reduction, which is already tried and tested in the commercial-vehicle segment, and modified it to passenger-car requirements. Diesel cars have been fitted with this technology in the United States since 2009, specifically to comply with the particularly stringent exhaust emissions legislation there; these diesel vehicles are now also available in Europe as Euro 6 models. To meet even more stringent emissions limits and to reduce fuel consumption and CO2 emissions even further, Bosch is currently developing injection systems that can generate more than 2,000 bar – equivalent to a load of two metric tons on a single square centimeter. In the case of piezoelectric injectors that provide up to eight injections per working stroke, the injection time is now less than a millisecond, with injection taking place at more than twice the speed of sound.
The future is diesel
Bosch diesel technology will pave the way over the next few years for even more efficient passenger-car drives based on the internal-combustion engine. Taken together, all the individual technical developments associated with the internal-combustion engine are giving rise to engine concepts that will be ready for the market in 2015. The diesel engines of the future will have just three cylinders and a displacement of some 1.1 liters, thanks to extreme downsizing. And yet they will offer dynamic, refined driving characteristics with an output of roughly 100 kilowatts. They will be fitted with a slew of additional products, all of which will combine to increase the efficiency of the powertrain:
■A start-stop system to automatically switch the engine on and off when the vehicle comes to a stop, for instance at lights or in traffic jams
■Thermal management to get the engine quickly up to the optimal operating temperature and keep it there
■A highly efficient alternator which utilizes brake energy as one source for charging the battery.
Diesel passenger cars of the future will run even more efficiently thanks to Bosch technology. So much so that a diesel-powered car in 2015 will consume just 3.6 liters to drive 100 kilometers. That is some 30 percent less fuel than a 2009 standard diesel model uses. With hybridization, the fuel consumption of diesel engines will be reduced by as much as some 40 percent. Bosch engineers are already working on systems for future engine concepts that are being devised by automakers and will therefore continue to promote the refinement of internal-combustion engines.
Milestones: 75 years of diesel in passenger cars
Initial trials of diesel injection with Bosch oilers
Official start of development for diesel fuel injection
First prototypes of diesel injection pumps
Series production of injection pumps and nozzles for commercial vehicles
10,000th diesel injection pump
Regulator for injection pumps
Pneumatic injection pump regulator
100,000th diesel injection pump
Start of diesel injection system for passenger cars
1,000,000th diesel injection pump
First VM distributor pump
VE distributor pump
EDC electronic diesel control for distributor pumps
EDC electronic diesel control for in-line pumps
VP37 axial piston distributor pump for direct injection in passenger cars
VP44 radial piston distributor pump
Start of series production of the CP1 high-pressure pump at the Bari plant, Italy
Start of CRI1 injector production in Bamberg, Germany
Injection pressure: up to 1,350 bar
Unit injector for passenger cars
Bosch and Fiat awarded the “Paul-Pietsch Prize” for the common rail system as a groundbreaking technical innovation
One millionth common rail system produced
Second-generation common rail for passenger cars
Injection pressure: up to 1,600 bar
Production of common rail components in Charleston, USA
Ten millionth common rail system produced
Common rail for passenger cars, third generation with piezoelectric injectors; Injection pressure: up to 1,800 bar
“German Future Prize” for the development of piezoelectric injectors for diesel injection systems
Start of production for common rail components in Nashik, India
Diesel engines reach a market share of over 50 percent in western Europe
The Audi R10 TDI with a diesel engine and Bosch injection technology wins the Le Mans race. Additional Le Mans victories in 2007, 2008, and 2010
Bosch produces the world's first 2,000-bar injection system
Bosch Denoxtronic for exhaust-gas treatment in diesel passenger cars, receipt of the “Öko-Globe” environmental prize in the “Supplier Innovation” category
PSA Peugeot Citroën and Robert Bosch GmbH seal a strategic partnership agreement to develop diesel hybrid technology
50 million common rail systems manufactured by Bosch
First Euro 6 vehicles on the market use clean diesel (five years before Euro 6 becomes compulsory)
First Bosch-equipped diesel hybrid goes into series production at PSA Peugeot Citroën