Exel: Dual-fuel OOOOOOOOO • • • • • • • • • • • • • • •
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• Exel Tradeteam was at MIRA to try a dual-fuel (diesel/compressed natural gas) conversion from the US company Innovative Technology Group which is marketed in the UK by Emissions Possible of Maldon, Essex. This retrofit kit, which costs about £10,000, allows the engine to run on a mixture of diesel and ONG: the engine starts on pure diesel but switches to a mixture of up to 70% gas as it warms up.
The gas is injected at a single point into the air intake between the air filter and the turbocharger so the engine itself is essentially unchanged—there is always enough diesel injected for ignition without recourse to spark plugs to ignite the gas.
The ITG dual-fuel kit was fitted to a Tradeteam 18-tonne MAN 18.224 rigid that averaged 1014mpg when running on pure diesel over both sections of the BTACARTE trial. Having switched to dual-fuel mode, the volume of diesel was cut by 44% but a quantity of gas was also consumed—this was replenished off-site and was not audited by the BTAC marshals. The easiest way to assess the figures is to convert both fuels to a monetary value. On pure diesel the run cost £19.57; on on dual-fuel it cost £16.53—about 15% less. Whether the payback period is acceptable will depend on vehicle utilisation and the price of CNG. This varies significantly with the amount used because of the need to recover the cost of the gas compression and refuelling station.