Fining idling diesels

Posted on September 4th, 2014 by Rob Marshall

dieselWhile laboratory-conducted European fuel consumption tests have proven to be totally unrealistic in real-world conditions, the consequence is not just irate new car owners. Tailpipe pollutants have also been underestimated, which is only just being realised, with certain built-up areas exceeding (the ironically-set) European limits on air pollution.

All of this has made a mockery of the entire principle of focussing on carbon dioxide (CO2) being used as the main measure, on which the UK government calculates road and company car tax rates. While diesel rates are slightly higher than those of petrol engines, with an equivalent CO2 output, there have been calls for diesel drivers to pay more in charges and fines. While heavy-oil fuelled engines are more efficient on fuel, than the equivalent petrol, or LPG, motor, and produce fewer pollutants, such as CO2 and Carbon Monoxide (CO), let alone not dosing the user’s lungs with fumes at fill-up time, its propensity to emit more NOx gases and fine particulates has become the prime focus.

In particular, with the City of London failing to comply with the ironic European clean air targets, Mayor Johnson has proposed that diesel car motorists predominately would have to stump-up extra money to enter the capital, presumably as a means to pay the European fines, rather than coming up with a strategy that will actually reduce the city’s NOx emissions. In an ill-judged and reactionary move, The Sun newspaper is calling on a diesel scrappage scheme, even though that will force many perfectly-serviceable vehicles off the road, which is far more environmentally damaging. In response, The Telegraph has given a more balanced view. Incidentally, CAP, the vehicle valuation exponents, has commented that Boris’ announcement is unlikely to affect enough vehicles, for diesel car valuations to be hit hard, unless the scheme is rolled out by all cities, across the UK.

Yet, Islington Council has started fining drivers of diesel cars, who leave their engines idling, while stationary. While the authority has stated that the move is part of its commitment to improve air quality in Islington, it might have little overall benefit and will, almost certainly, result in more wear-and-tear on the vehicles that are subjected to prolonged and repeated engine restarts, while introducing another motorists‘ annoyance factor. However, it is worth highlighting that it is illegal to leave an engine running in an unmanned vehicle.

Obviously, ailing batteries and alternators are likely to be caught out and I would not be surprised, if the number of breakdowns increases in the area. Furthermore, longer term wear to items, such as dual mass flywheels (which cycle though their operating range at every stop and restart), starter motors and even turbochargers, is probable.

Additionally, continually restarting is likely to increase the soot loading inside the Diesel Particulate Filter, more so than were the engine left idling, meaning a further increased risk of breakdown. Also, with the engine stopped, the temperature of the exhaust system will decrease, meaning that the various emission control functions (such as the oxidisation catalyst) are at risk of not working as efficiently, when the engine is restarted, thus, potentially and counter-productively, increasing the emitted pollutants.

So, is Islington’s proposal to fine the idling motorist another well-intentioned but ill-thought out wheeze? It appears that it might well be the case but for the wrong reasons.