Tuesday 10 July 2012

Cat Show. All About A Car Exhaust’s Cleaning Component

On petrol cars, a catalytic convertor has become a standard part of the car exhaust. Catalytic convertors – ‘cats’ for short – originated in America. Like many other items, cats soon went transatlantic and later made their way into European legislation. Unsurprisingly, they wound up in the UK.

Let’s begin with the nuts and bolts of the matter. In chemistry, a ‘catalyst’ is a substance that causes or accelerates a chemical reaction without itself being affected. Fair enough but what has this to do with car exhausts? Still talking at nuts-and-bolts level, a catalytic converter is a device that uses a catalyst to convert three harmful compounds in car exhaust gases into harmless chemicals.

Again, fair enough but what are these three compounds that are so harmful? They are to be found in the exhaust gas of any petrol car and consist of…

Hydrocarbons (incompletely burnt fuel)

Carbon Monoxide (formed when petrol burns)

Nitrogen Oxides (made by combustion heat making atmospheric nitrogen combine with oxygen.)

So, just how scary are these components in car exhaust gases? Carbon Monoxide, a.k.a. CO, is the nastiest one, being poisonous to any organism that breathes air. Nitrogen oxides (NO2) lead to the formation of both smog and acid rain. Relatively innocent Hydrocarbons (HC) just produce smog but are particulate matter, which makes matters worse.

A catalytic convertor, looking rather like a silencer, forms part of a car exhaust system. The catalyst used is liable to consist of precious metals such as rhodium, platinum and palladium. These coat a ceramic honeycomb or ceramic beads inside the ‘cat’. Carbon monoxide is converted into the less harmful carbon dioxide (CO2) and hydrocarbons are converted into carbon dioxide (CO2) and water (H2O). As for the nitrogen oxides, these are converted back into nitrogen and oxygen.

Though they don’t have moving parts, ‘cats’ can suffer malfunctions. If the catalytic convertor in a car exhaust stops working, you won’t necessarily know about this until your next MOT test. A failed cat may just be worn out or its substrate (the metal-coated pellets or ceramic honeycomb inside) may have broken down. Your car may run perfectly well – it just won’t be able to pass the emissions test part of an MOT.

Often, diagnosing what’s awry with the cat in a car exhaust is tricky. If something has gone wrong with the car’s fuel system and it allows raw fuel into the cat, the unit will run red hot. This is usually pretty easy to detect, which is just as well, as the substrate can shatter at such temperatures. Fouled sparking plugs, incorrect ignition timing and failure of the engine’s air pump and/or check valve can also cause overfuelling.

Should the cat’s innards go into meltdown, or shatter through thermal shock or overheating, the result will mimic a blocked car exhaust. A sluggish throttle response is the major clue. Modern electronics mean that a fault light will flash to verify there’s a problem but detecting exactly what the problem is likely to involve diagnostics – on a laptop computer. In any event, should the problem lie within the ‘cat’, a good tyre and exhaust bay will be able to offer you a replacement unit.

Article Resource

Merityre.co.uk are one of the leading UK independent suppliers of car tyres. Why not visit their website for an online tyre quote or contact your nearest fitting centre.

Tyres On Trial

Suppose you were regularly wearing out a set of tyres on your Mini Cooper in three miles. You’d certainly be doing something very wrong, wouldn’t you? However, this is the usual car tyre mileage on one of The Russ Swift Mini Display Team’s Coopers and Russ is doing something very right – in the eyes of his sponsors and spectators, that is.

The Team, part of Russ Swift Driving Services, was formed in 1981. Current British Autotest champion and England Autotest Team Captain Russ had often been asked to demonstrate his incredible, tyre-testing car control skills. He realised a gap existed in the marketplace and contrived to fill it.

In 1987, an advertising agency saw a video of Russ at work. This led to the renowned Montego “Car Park” commercial. Though this was aired in the UK for just six weeks, the squeal of tortured car tyres was heard when the performance was featured at the Cannes Film Festival. It was also voted by American judges as the world’s most imaginative car commercial.

Where did Russ go from there? A long, long way. Eight thousand tyre-munching displays in more than 50 countries and three Guinness world records (Parallel parking in the tightest space, J Turn in the tightest space and the fastest donuts) form just a small part of his CV.

Russ and Minis go back a long way too, starting with four British Autotest Championship wins and an International Rally win in Sweden in the early eighties, in a Cooper S. More recently, Russ was involved in promoting the remake of ‘The Italian Job’, performing at premieres in London and New York. He fulfils an advisory role with many police, military, royal and diplomatic drivers, also working closely with RoSPA, the IAM and various other road safety bodies to promote safe driving. A versatile player on the car world’s stage, Russ is committed to ensuring that it is only car tyres that suffer!

The tools of Russ’s trade are largely unmodified cars. Russ uses a Mini Cooper S, standard apart from a “piece of tape on the handbrake button”. Another Mini Cooper has one other mod – a locked differential – to allow for driving on two wheels (this is the one that gets 3 miles per set of tyres – should that be per pair?). Typically, a further Mini Cooper is used (all these are BMW MINIs). Often, an MR RS Mitsubishi Evolution undertakes power slides and donuts.

A typical show features reverse spins at 40mph, parking in a slot between two cars parked side by side, using only the handbrake. Similarly, ‘parallel parking’ involves a handbrake turn into the gap between two cars parked as though at the kerbside. Then there is a ‘dance routine’ to music, involving two cars and a ramp. This last – the ramp – is used for the business of getting the locked-diff Cooper up on two tyres. The show features music and commentary – and audience participation is encouraged. The tyres may be red hot but the invited passengers have been known to end up on the pale side!

Find out more – and see pictures and videos – at www.russswift.co.uk.

Article Resource

Merityre.co.uk are one of the leading UK independent suppliers of car tyres. Why not visit their website for an online tyre quote or contact your nearest fitting centre.