Bosch claims new tech cuts NOx levels in diesels

Bosch has announced a new technology for diesel engines, which it claims, will reduced the real driving emissions (RDE) from cars.

Bosch has claimed that the new technology can help carmakers to meet not just the current limits, but also those which are scheduled to be implemented in 2020. Current European norms ask for a maximum of 168 mg of NOx per km in RDE tests. This limit will be brought down to 120 mg per km by 2020. The company is claiming a reduction in NOx levels to 13 mg per km in the same tests.

According to Bosch, a vehicle equipped with this technology, was driven around town in presence of journalists and the NOx levels were monitored. Even in urban tests, where NOx levels are known to be higher, the car reported only 40 mg per km. The technology is available today and requires changes to the fuel injection, air management system and exhaust gas temperature control. It was also claimed that these measures to lower the NOx emissions are not expected to affect the vehicle performance and fuel consumption significantly.

The technology works on improving the two scenarios that are believed to lead to a higher NOx emission in cars - aggressive driving style and urban conditions. The company claims to have used a turbocharger that spools faster. A combination of high and low-pressure exhaust gas recirculation is used to improve the flexibility of the system in different conditions. This results in lower emissions at speed and while accelerating. In cities, the exhaust gases are unable to reach the ideal temperature of 200 degree Celsius for optimum NOx conversion. A thermal management system regulates the exhaust gas temperatures to solve this problem.

The company has also clarified that this technology makes use of existing components and potential customers (carmakers) can incorporate it into their production immediately. It also doesn't require the installation of an additional 48V on-board system. As the components are readily available, it is not expected to result in an increase in the costs.

Bosch has also been developing a diesel engine that is not likely to be affected by ambient temperatures.