Diesel engine

Modern diesel engines: a negligible effect on air quality

Modern diesel engines no longer make a noteworthy contribution to NOx immission values while retaining their advantage in terms of CO2 emissions and affordability. Not only that: the modern diesel engine is already out on the road.

Technological progress for better air quality

Diesel engines are not always immediately associated with low NOx emissions. This is a mistake, as Michael Krüger explains. After all, modern diesel powertrains barely emit any nitrogen dioxide these days, while particle filters also stifle particulate matter.

In our expert interview, you will learn why long-distance vehicles cannot do without diesel engines, how even carbon neutrality can be made possible in the future, and why modern diesel engines are a key element in the future mix of powertrain technologies.

The numbers make a case for modern diesel engines

A diesel that conforms to the Euro 6 exhaust-gas standard emits some

15%

less CO2 than a comparable gasoline engine.

In practical tests

compliant

with the Euro 6 standard, test vehicles equipped with Bosch’s new diesel technology emitted an average of just 13 mg of NOx per kilometer.


Crucial

for achieving the EU’s fuel-efficiency and emissions targets

Real tests, precise results: Bosch advocates RDE measurements

Measuring emissions under real operating conditions (real driving emissions or “RDE” for short) makes a major contribution to improving air quality. This also enables the discrepancies between emissions values recorded on a test bench and those resulting from driving profiles on the road to be reduced.

This is because faster acceleration, inclines, stop-and-go traffic, and higher speeds alike are all taken into consideration. Bosch has actively supported the introduction of RDE measurements in recent years.

Cold starts: effective measures against NOx emissions

Cold starts are a challenge, which is why developers at Bosch have dedicated so much attention to them. A well-coordinated interplay between engine and exhaust-gas treatment is essential: if the exhaust-gas treatment system is not yet achieving high conversion rates, the engine assists both by increasing the exhaust-gas temperature and with lower raw NOx emissions.

Precise models in the ECU software ensure that measures, particularly those requiring greater amounts of fuel, are only implemented in a targeted manner when they are really necessary.

Improved components for diesel powertrains

Diesel-powered cars

Diesel-powered cars equipped with Bosch components achieve a NOx value of 13 mg/km thanks to a number of elements: an improved injection system (e.g., with needle-closing control) lowers tolerances. The engine assists exhaust-gas treatment by increasing the exhaust-gas temperature and keeping raw NOx emissions low.

A highly dynamic turbocharger assists in enabling transient driving with exhaust-gas recirculation up to the full load. A double-injection SCR system that doses AdBlue® at two points helps to achieve a further reduction in emissions.

The diesel engine, designed for the future: Bosch common-rail injection systems

The efficiency of diesel engines has been steadily increased over decades of further development and refinement. No internal-combustion engine is used in such a diverse range of applications as the diesel engine. The demands placed on the injection systems are correspondingly high. This is where Bosch can make a difference – whether for higher pressures, faster switching times, or flexible adaptation of the injection process to the operating state.

Bosch is committed to the continued development of fuel injection to produce common-rail systems that deliver the very highest performance while helping owners comply with current legislation at the same time.

CRS 3-27 common-rail system with piezo injectors

CRS 3-27 common-rail system with piezo injectors

Quieter, more powerful, and mainly more flexible: The main advantage of the CRS 3-27 system is its great flexibility. The permanently available injection pressure – irrespective of rotational speed and load – makes defining the start, duration, and quantity for the injection process flexible. A system pressure of up to 2,700 bar and an output of around 100 kW/l guarantee very high engine performance with comparably quiet combustion achieved with up to ten individual injections per cycle.

Learn more

CRS 2-25 common-rail system with solenoid injectors

CRS 2-25 common-rail system with solenoid injectors

A robust system for high output: The CRS2-25 system provides a system pressure of up to 2,500 bar and around 90 kW/l for high performance. Just like the CRS 3-27, the injection process with solenoid-valve injectors also enables powerful performance to be delivered across a wide range of rotational speeds.

Both systems can be easily installed on the engine and enable flexible injection control. Having up to ten injections per cycle also enables very quiet running with the CRS 2-25 system.

Learn more

DI-SCR: double the efficiency to protect the environment.

DI-SCR

Satisfying current and future emissions requirements is one of the most significant challenges faced by the automotive sector.

For this reason, Bosch has developed DI-SCR – an SCR technology that uses a double injection of urea. In combination with high-performance temperature management, DI-SCR succeeded in reducing a diesel engine’s NOx emissions to just 13 mg/km.

In each specific driving situation, the system injects urea into two catalytic converters: one close to the engine and one further away. The results are dramatically lower nitrogen values (even at high loads), lower AdBlue® consumption, and reduced infiltration of ammonia into the low-pressure exhaust-gas recirculation system.

Learn more

Further solutions

Electronic engine-control unit

Electronic engine-control unit

The electronic engine-control unit (ECU) is the central control device and centerpiece of the engine management system.

High-pressure pump

High-pressure pump

Fuel supplied to the connected rail at high pressure.

High-pressure rail for common-rail systems

High-pressure rail for common-rail systems

The high-pressure rail lends its name to the common-rail system and, as the central hydraulic component, connects the pump with the injectors.

Piezo injector for common-rail systems

Piezo injector for common-rail systems

The rapidly switching CRI3 piezo injector offers a great degree of freedom when designing the injection characteristics.

Solenoid-valve injector for common-rail systems

Solenoid-valve injector for common-rail systems

Depending on the individual driving situation, the CRI2 injects the amount of fuel required for efficient combustion into the cylinder.

Denoxtronic supply module

Denoxtronic supply module

The supply module provides the urea needed to reduce NOx levels.

Denoxtronic dosing module

Denoxtronic dosing module

The dosing module is part of the Bosch Denoxtronic system and sprays AdBlue® (a mixture of water and urea) into the exhaust-gas system.

Denoxtronic dosing control unit

Denoxtronic dosing control unit

The electronic control unit controls and monitors all functions and active components involved in exhaust-gas treatment.

Please contact us

Contact icon

Contact form
Bosch Mobility Solutions

Are you interested in our solutions? Please don't hesitate to contact us! We will be glad to help you.

Start enquiry