NOx Diesel Emissions Reduced Thanks to New Technology from Bosch
There’s been a lot of misinformation, confusion and misconception surrounding the use of diesel vehicles over the past 15 years or so. Suffice to say that the public may have been wrongly encouraged to buy into diesel from some quarters. Diesel engines are not the right choice for a car that doesn’t get a good motorway workout. Certainly not the right choice for light trips to the supermarket once a week.
Having said that, we are now in a situation where there are plenty of diesel vehicles out there and plenty of owners who feel that they have been misled. So a new invention from the renowned German automotive company Bosch, is worth looking at.
Right now, cars are not allowed to pump out more that 168mg/km of NOx (nitrogen dioxide and nitric oxide; the gases that collude to form acid rain and smog) with the limit set to be cut even more in 2020 – that’s just 2 years away – to 120mg/km) and NOx emissions tends to be higher from a short journey engine that hasn’t reached optimum temperature.
Bosch has announced that it have invented a system that allows a Volkswagen Golf to push out 13mg/km –even in built up urban low engine temperature driving, the figure is just 26mg/km. This is of course a huge drop and intriguing news. The testing that Bosch has carried out has been sensible; that is real world driving rather than just sanitised lab tests, meaning that the figures claimed are likely to be far more accurate in every day use.
How Does It Work?
Bosh used a modified engine to make the tests generic rather than VW-specific, and it involves optimised turbo-chargers and intelligently managing the recirculation of exhaust fumes to reduce emissions – even in stop-start urban situations and while the engine is at a lower temperature. Bosch says that the technology kicks in immediately each time.
A series of improvements across the board allow marginal gains that result in the diesel engine being able to manage exhaust fumes more efficiently. The diesel engine’s catalytic reduction system needs to be kept hot to be most efficient – hence the issue when not on a long motorway haul and merely popping to the shops or on the school run – especially on a cold winter morning. Bosch’s solution to this has been to move the system closer to the engine – as the engine warms up, so the SCR warms up much faster utilising the constant heat from the engine. Couple this with more efficient turbo-chargers (less energy waste), plus optimising the fuel injection system and you begin to see how the system can improve the engine efficiency and thus reduce NOx output.
Interestingly, the adapted VW engine that Bosch used began life as a 2-litre, but Bosh reduced this to a 1.7-litre with no noticeable decrease in power due to the engine enhancements made. Bosch do admit that stop-start driving and winter may see a slight increase in fuel used. Up to 5 per cent in extreme cases according to Dr Michael Krüger, head of diesel development at Bosch.
Because the system is not just one item that can be fitted to an engine, the changes cannot be made to an existing diesel engined car. So current vehicles on the road will remain a problem without a forthcoming solution.
Bosch say that in real world terms, we could be looking at around two years before manufacturers are able to realistically implement these changes into new models.
Is this a lifesaver for the future urban domestic diesel user? I doubt it; that ship has sailed – but it may prove to the salvation of haulage companies, public transport and the motorway residing rep.
Image Credit: autoexpress.co.uk