Cutting harmful diesel engine nitrogen oxide emissions

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EPSRC-supported researchers at Loughborough University have developed an industry-first technology with the potential to significantly cut nitrogen oxide (NOx) emissions in diesel engines.

  • Use of the NOx reduction system could significantly reduce tailpipe emissions
  • SCR system, while tailored for HGVs, is scalable for use in all diesel vehicles
  • Diesel engine emissions have led to over 50,000 additional deaths in the UK

The Government estimates that exposure to NOx and particulate matter emissions from diesel engines has led to over 50,000 additional deaths in the UK. Currently almost all new diesel vehicles are fitted with a Selective Catalytic Reduction (SCR) system to try and remove NOx produced by combustion. This system uses a product known as AdBlue™ to safely provide the ammonia required to reduce NOx into harmless nitrogen and water.

The drawback is that AdBlue™ only functions well at high exhaust temperatures, typically in excess of 250ºC. Therefore, the SCR does not necessarily operate at all engine conditions, for example, during short, stop-start commutes, particularly in urban areas or on construction sites.

Use of AdBlue™ at these problematic lower temperatures can also result in severe exhaust blockages and subsequent engine damage.

Now, Professor Graham Hargrave and Research Associate Jonathan Wilson have developed an AdBlue™ conversion technology that uses waste energy to modify it to work effectively at these lower exhaust temperatures. By greatly extending the temperature range at which SCR systems can operate the new Ammonia Creation and Conversion Technology (ACCT) significantly, enhances existing NOx reduction systems.

No viable alternative to the diesel engine currently exists for the heavy duty market and diesel is going to be in use for many more years. The technology, while tailored for HGVs, is scalable for use in all diesel vehicles.

Research Associate, Jonathan Wilson, says: “Our system enables the SCR systems to work at temperatures as low as 60oC. This means that the NOx reduction system remains active through the whole real-world driving cycle, leading to significant reductions in tailpipe emissions.”

ACCT has won The Engineer 2017 Collaborate to Innovate Transportation Award and the Times Higher Education 2017 Technology Innovation of the Year Award.

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