Bosch might just have solved the problem of diesel NOx emissions – Too Little Too Late Though?
Bosch's solution to the NOx problem involves optimizing a number of different steps in the process. Engine displacement is reduced from 2.0L down to 1.7L. The turbocharger has been tweaked to be more responsive, thereby improving transient and low-end torque behavior. Exhaust gas treatment has been enhanced to increase the temperature of the catalyst as quickly as possible upon startup.
The engine also has to maintain those high temperatures (above 392° Fahrenheit/200°Celsius) while driving, otherwise the exhaust gases themselves can cool the catalyst below the point at which it's most effective. New engine management software is optimized for low fuel consumption at a lower NOx level. High- and low-pressure exhaust gas recirculation means the engine's air flow management is more finely controlled, coupled with revised fuel injection to reduce transient NOx peaks.
The result is an engine that can emit as little as 13mg/km NOx and just 40mg/km even under the worst conditions. Even at 40mg/km, that's half the 2020 European NOx limit, which sets the limit for diesel-engined passenger cars at 80mg/km. (Although technically I should point out that the regulations actually allow cars to emit 1.5x that amount in 2020, compared to 2.1x that amount today.) Meanwhile, in the US under a different testing cycle, the federal limit is just 40mg/km.
It is also quite a bit above zero emissions while driving… This could have made quite a difference before Dieselgate if it could have prevented the fallout, but Dieselgate happened, and things have moved on with better prospects becoming far more viable. At best this may buy some more time for diesel engines but I'm still not rushing out to buy one.
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Bosch might just have solved the problem of diesel NOx emissions The solution involves combining a number of existing technologies. |