Lowering diesel emissions even further
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"Modern diesel engines are very attractive thanks to their high torque at low revs and their low fuel consumption", says Dr. Ulrich Dohle, President of Diesel Systems Division of Robert Bosch GmbH, in a speech to the Stuttgart-based components supplier's Automotive Press Briefing.
(Click on the photo to enlarge. High resolution versions are available)
Bosch is pursuing a large number of technical improvements with the aim of further reducing harmful emissions from diesel engines and thus of making these engines even more environmentally-friendly. Following on the introduction of the Euro 4 emissions standards, the focus of Bosch's development efforts is on the prospective Euro 5 standards, which will apply from 2010 and which are currently being debated in the EU Commission in Brussels. Euro 5 represents an enormous challenge for the development engineers in respect of emissions of nitrogen oxides (NOx) and particulates: for particulates, a maximum emission level of a fifth of the current Euro 4 standard is being discussed. That can only be met by using particle filters on all diesel cars.
As well as a diesel particle filter (DPF), Bosch is also developing a new injection system which will feature extremely precise metering of fuel in order to further reduce the levels of harmful emissions. High injection system pressures and variable control of the injectors through which the fuel is injected into the combustion chambers are both centrally important here. By using novel piezo-electric technology and maximum injection pressures of 1600 bar, the 3rd generation of the Common Rail system introduced by Bosch in 2003 is already capable of meeting the current Euro 4 limits without employing additional exhaust gas aftertreatment. In view of the further improvement to fuel mixture preparation required by the Euro 5 standards aimed at lowering raw emissions, Bosch is planning to develop and market the Piezo Common Rail system for system pressures of up to 2000 bar.
(Click on the photo to enlarge. High resolution versions are available)
Bosch is also developing the 4th generation of the Common Rail system with a "Hydraulically Amplified Diesel Injector" (HADI). Using a pressure-amplifying piston, it will enable injection pressures of up to 2500 bar to be achieved. "This new technology opens up the possibility of operating with a significantly lower pressure in the Common Rail itself, with the required maximum pressure only being generated in the injector", explains Dohle. In addition to the Common Rail systems, the development engineers are also working on improving the Unit Injector System. The latest UIS3 generation designed by Bosch operates with two actuators instead of one and allows the injection process to be variably configured, with five injections per cycle, similar to the 3rd and 4th generations of the Common Rail system.
In order to exploit the potential of its injection systems to the maximum, Bosch is developing a new engine control unit (EDC17), which will go into series production in 2006. Using revolution counters, the system can analyze the injection parameters of each cylinder and adjust them if necessary. The system permits a simple control system which can easily be transferred to a variety of engines and which benefits from the direct feedback from the engine. Precision and resistance to mechanical wear can be optimised.
For breaking down nitrogen oxides in diesel engines, either NOx storage catalytic converters (NSC) or SCR systems are employed. SCR systems require the reducing agent 'AdBlue', which converts the nitrogen oxides into nitrogen and water. Bosch is developing dosage units and control unit designs for these SCR systems. This will allow an especially effective removal of nitrogen oxides with a conversion rate of up to 85 percent.
"These are some of the innovative solutions which Bosch is offering in order to lower emissions in all diesel cars and commercial vehicles", says Dohle.
Innovative technology from Bosch for clean and fuel-efficient diesel engines
- 4th generation Common Rail with pressure amplification
- Unit Injector system for improved combustion
- Bosch solutions for exhaust gas aftertreatment
"Modern diesel engines are very attractive thanks to their high torque at low revs and their low fuel consumption", says Dr. Ulrich Dohle, President of Diesel Systems Division of Robert Bosch GmbH, in a speech to the Stuttgart-based components supplier's Automotive Press Briefing.
(Click on the photo to enlarge. High resolution versions are available)
Bosch is pursuing a large number of technical improvements with the aim of further reducing harmful emissions from diesel engines and thus of making these engines even more environmentally-friendly. Following on the introduction of the Euro 4 emissions standards, the focus of Bosch's development efforts is on the prospective Euro 5 standards, which will apply from 2010 and which are currently being debated in the EU Commission in Brussels. Euro 5 represents an enormous challenge for the development engineers in respect of emissions of nitrogen oxides (NOx) and particulates: for particulates, a maximum emission level of a fifth of the current Euro 4 standard is being discussed. That can only be met by using particle filters on all diesel cars.
As well as a diesel particle filter (DPF), Bosch is also developing a new injection system which will feature extremely precise metering of fuel in order to further reduce the levels of harmful emissions. High injection system pressures and variable control of the injectors through which the fuel is injected into the combustion chambers are both centrally important here. By using novel piezo-electric technology and maximum injection pressures of 1600 bar, the 3rd generation of the Common Rail system introduced by Bosch in 2003 is already capable of meeting the current Euro 4 limits without employing additional exhaust gas aftertreatment. In view of the further improvement to fuel mixture preparation required by the Euro 5 standards aimed at lowering raw emissions, Bosch is planning to develop and market the Piezo Common Rail system for system pressures of up to 2000 bar.
(Click on the photo to enlarge. High resolution versions are available)
Bosch is also developing the 4th generation of the Common Rail system with a "Hydraulically Amplified Diesel Injector" (HADI). Using a pressure-amplifying piston, it will enable injection pressures of up to 2500 bar to be achieved. "This new technology opens up the possibility of operating with a significantly lower pressure in the Common Rail itself, with the required maximum pressure only being generated in the injector", explains Dohle. In addition to the Common Rail systems, the development engineers are also working on improving the Unit Injector System. The latest UIS3 generation designed by Bosch operates with two actuators instead of one and allows the injection process to be variably configured, with five injections per cycle, similar to the 3rd and 4th generations of the Common Rail system.
In order to exploit the potential of its injection systems to the maximum, Bosch is developing a new engine control unit (EDC17), which will go into series production in 2006. Using revolution counters, the system can analyze the injection parameters of each cylinder and adjust them if necessary. The system permits a simple control system which can easily be transferred to a variety of engines and which benefits from the direct feedback from the engine. Precision and resistance to mechanical wear can be optimised.
For breaking down nitrogen oxides in diesel engines, either NOx storage catalytic converters (NSC) or SCR systems are employed. SCR systems require the reducing agent 'AdBlue', which converts the nitrogen oxides into nitrogen and water. Bosch is developing dosage units and control unit designs for these SCR systems. This will allow an especially effective removal of nitrogen oxides with a conversion rate of up to 85 percent.
"These are some of the innovative solutions which Bosch is offering in order to lower emissions in all diesel cars and commercial vehicles", says Dohle.
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