Dirk Naber

Advanced diesel technology to meet multi-dimensional challenges of the diesel engine

The modern Common-Rail Diesel engine is no more a European phenomena while the long-term prognosis shows growth of about 9% in India and China. In India the Diesel engine has already a high share in the market due to the need of low operating cost while in China there is not only an ever increasing demand for light commercial vehicles but also for Passenger Cars. These two markets need robust and cost attractive Diesel Injection Systems, which must also be capable to fulfill the new emission norms like BS5 (Bharath Stage 5) or CN5 (China 5), while facing challenging environmental conditions, fuel quality and OEM requirements different to Europe. On the other hand the requirements for the European High-End Segment are not only to consume less fuel with the same power output – but to have the same noise and comfort level like a comparable DI-Gasoline-engine. Key enablers are a multiple injection capability with very short hydraulic dwell times combined with excellent mixture formation and more system injection pressure of up to 3000bar to achieve power output targets above 100 kW/l. Based on broad system competences in terms of Diesel combustion and control, Bosch offers tailored solutions for all segments and markets and adopts a modular approach, which actively builds upon the achieved maturity of functional groups and concepts. The resulting portfolio of Solenoid injectors and Piezo injectors are presented herein.

Operating strategy for optimized CO2 and NOx emissions of diesel-engine mild-hybrid vehicles

Over the last decades the pollutant emissions of passenger-car diesel engines have been reduced significantly. Particulate emissions were cut back to a minimum with the introduction of diesel particulate filters. The upcoming EU6 exhaust regulation will further reduce the nitrogen-oxide emissions. In many cases an efficient nitrogenoxide exhaust-gas aftertreatment system will be installed. In the years to come, however, the requirements for passenger-car diesel engines will become even more demanding in various regards. On the one hand, current discussions are focusing on the registration of pollutant emissions produced during real driving (RDE, real driving emissions). Compared to the currently applicable European driving cycle for passenger cars future test cycles will include stricter requirements regarding output and transient operations. On the other hand, significant further reductions of CO2 emissions must be achieved for all passenger cars. For this purpose, improvements on the diesel engine (e.g. reduced friction, further development of more efficient combustion methods, etc.) will be complemented by various approaches of hybridization. Robert Bosch GmbH is running comprehensive studies on the optimization of the operating behaviour of hybridized diesel-engine powertrains. The aim of these studies is to develop scalable engine-control functions resulting in the efficient and optimum matching of the diesel engine and the hybridization concept. The functions presented in this paper support the significant further reduction of the NOx emissions of diesel passenger cars especially under real driving conditions while leading only to minor fuel consumption penalties.

Advanced diesel fuel injection equipment – A never ending BOSCH story

Since the very beginning of providing fuel metering equipment for Diesel combustion engines, injection pressure is one key enabler for mixture preparation and spray performance. A second important enabler is the injection pattern, fulfilling the task to bring the fuel into the combustion chamber in the right time, with the right quality and to the right place. This paper deals with the role of injection pressure and patterns for Diesel combustion engines fulfilling upcoming ultimate requirements for developed markets. Future requirements on propulsion coming from the overall market trends especially on emission and CO2 by means of fuel consumption are discussed. As the key technology for internal combustion engines direct fuel injection in Diesel plays a major role gaining the challenging development targets like power output, gasoline noise level, lowest emission and benchmark fuel consumption at an attractive cost level. This trend is already established in Western Europe and North America followed by the Asia market and will be rolled out in the next upcoming decade.

Measures to fulfill

The first stage of the regulations on real-driving emissions (RDE) has become effective in Europe in September 2017. Now compliance with the EU6d_temp stage is required in order obtain a type approval. This regulation aims to limit the nitrogen-oxide and particulate emissions. With residual emissions from diesel cars having only very small contribution to finedust in cities due to the broad-based use of particulate filters, further development activities are now geared towards effectively limiting nitrogen-oxide emissions.

Measures to fulfill “real driving emission (RDE)” with Diesel passenger cars

Passenger car manufacturers are currently facing the task of controlling the real-driving emissions of cars on public roads in spite of highly varying driving conditions to such an extent that these emissions deviate only little or not at all from the emissions established during standardized type approval testing. The legislation on real-driving emissions (RDE) primarily aims at the particle count and nitrogen emissions. The widespread use of particle filters in modern diesel cars has already brought particle emissions produced during combustion down to an extremely low level; however, effectively limiting nitrogen emissions is in focus.

Bosch common rail for passenger car/light duty – The first 20 years

For a long time the image of the Diesel engine was seen as a fuel efficient, but noisy and phlegmatic power source for passenger cars. With the introduction of turbo charging this turned around the first time. A second big step was the cultivation of the direct injection combustion technology, as it once again added a significant fuel consumption reduction opportunity compared to the in-direct combustion systems of these days. With the injection of fuel directly into the combustion chamber the control of combustion was shifted away from air motion much more towards the injection itself. As in former times pre- or swirl chamber concepts defined the course of combustion, the shape of the injection rate became the dominant parameter of controlling the combustion process. These new requirements now defined the boundaries for the next generation of injection systems.

Bosch Diesel Fuel Injection System – with modularity from entry up to High-End Segment

The modern Common-Rail Diesel engine is no more a European phenomena and the worldwide prognosis shows growth not only in India and China but also in US market. In these markets the Diesel engines will be used in different vehicle segments and under different boundary conditions.