Writing for
Autocar, Steve Cropley recently highlighted technology — discovered by a team of British automotive research specialists at Loughborough University — that addresses the emissions of Nox from diesel engines.
Called ACCT (ammonia creation and conversion technology), this has reached the point that the university team is “being besieged by car manufacturers, component suppliers and even owners of large diesel fleets that have heard about the innovation and are desperate to use it to solve what they see as motoring’s most urgent problem”.
The team — led by Graham Hargrave (professor of optical diagnostics) and Jonathan Wilson (research associate) — has been working on exhaust emissions for many years but only achieved its breakthrough in the past two.
They say that from its current state, ACCT “should be fairly easy to engineer and could reach production within two years, with the right support”.
In essence, the system converts AdBlue, the universally available urea-based after-treatment, into a special ammonia-rich ‘ACCT fluid’; this is done under accurately controlled conditions in an exhaust-mounted chamber.
Like current selective catalytic reduction (SCR) systems, it then uses ‘freed ammonia’ to “literally to rip NOx apart”, leaving only nitrogen and water.
The team says the crucial difference between the two systems is that ACCT fluid maintains high levels of efficiency at the low-exhaust-temperature conditions that challenge current systems.
Preliminary tests on a city-based stop-start Skoda taxi indicate that ACCT can capture 98% of exhaust-borne NOx, compared with 60% for the same car running a conventional EU6 system — even before researchers had a chance
to ‘tune’ the ACCT system for the best performance.
Mr Hargrave says that while NOx has hit the headlines, CO
2 continues to “kill the planet. NOx is serious, but it’s really a point-source problem and only matters in a tiny minority of locations.
“However, solve Nox and you can get on with reducing CO
2, which is important everywhere.”