Exhaust pipe cleaner is DERT cheap

Emissions from diesel engines could be made almost two-thirds cleaner with Diesel Emission Reduction Technology, a device that fits conveniently to vehicle exhausts.

Emissions from diesel engines could be made almost two-thirds cleaner with a device that fits conveniently to exhausts. The Diesel Emission Reduction Technology (DERT) could be on the market next year.

Previously it has been difficult to fit filters to existing diesel engines, but the DERT is cheap to retrofit and could be applied to any size of vehicle, from road cars to marine diesels. It cuts particulates by 65 per cent, claimed its designer, engineer Julian Hasinki.

The system, which is fitted to the end of the exhaust pipe, contains a bank of replaceable filters made of cotton pleated between two layers of steel gauze. The cotton is untreated or impregnated with a flame-retardant chemical.

As each filter becomes clogged a bypass valve operates, re-routing exhaust gases to the next filter and illuminating a warning light on the dashboard. A network of agents would supply new filters and take in clogged filters to be chemically cleaned and reused.

Hasinski says the system would be much cheaper to retrofit than the only aftermarket rival, a type of continuously regenerating trap (CRT) that has to be installed near the exhaust manifold. Unlike a CRT it would not produce back pressure, giving better fuel efficiency.

Hasinski is aiming for a target price of £500 to install DERT, equivalent to the annual discount in road tax for vehicles of 15 tonnes and above that fit clean technology such as CRT. In subsequent years the tax rebate would cover the cost of replacing filters.

Nesta (National Endowment for Science, Technology and the Arts) has awarded a £31,000 grant for the technology to continue development. This will enable experimental testing at Sheffield Hallam University to be completed, and a batch of around 20 vehicles to be road tested by fleet operators such as local authorities.

Hasinski said that tests so far showed that one layer can trap 65 per cent of particles sized two nanometres and above. But experiments are continuing into different weaves, weave directions and ply.

The testing programme could be completed in six months to a year after which the product could be on the market ‘in a matter of a few months’.

DERT is patented in the UK, Europe and the US, but Hasinski believes there could also be a big market in India and Africa, where diesel fuel is of low quality.

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