Common rail diesels
IN days of old, diesel engines were very loud and belched out noxious fumes wherever they went. For this reason, they were largely the preserve of lorries, vans and a handful of best-forgotten cars.
Old diesel engines used a distributor-like injection pump which supplied bursts of fuel to injectors that sprayed diesel into the engine’s combustion chamber. The fuel was sprayed at low pressure and the amount was imprecise, meaning combustion was inefficient.
The common rail system replaces the old pump with a high pressure model that stores a reservoir of fuel in a ‘common rail’ – a tube attached to computer-controlled injectors, which precisely control the amount of fuel fired into the cylinders.
The result is cleaner-burning fuel, reduced exhaust emissions and increased efficiency.
Common rail technology revolutionised diesel engines, largely thanks to German automotive giant Bosch. Most major manufacturers now use it and fleets can’t get enough, because the engines combine the economy of diesel with tax-friendly CO2 emissions.
Catalytic converters
AS the battle to reduce harmful emissions continued, the catalytic converter made it possible to reduce pollution from exhausts without overly affecting performance.
Since 1993, all new cars in Europe have been fitted with catalytic converters by law.
The device is found under the car between the exhaust manifold and the tail pipe. Its job is to oxidise carbon monoxide to carbon dioxide, reduce nitrogen oxide to nitrogen and oxidise the hydrocarbons in unburnt fuel to carbon dioxide and water.
The device is made up of a honeycomb core, usually ceramic or stainless steel, and the catalyst itself, usually platinum, palladium or rhodium.
Pollutants from the engine pass through the catalyst, react with it and the less harmful results are released from the tail pipe.
With each year bringing more stringent environmental legislation, and current company car tax determined by CO2 emissions, the catalytic converter is a godsend to company car drivers and the wider public.
Satellite navigation
REMEMBER maps? They were an ingenious invention used by our ancestors to find their way around their shires, using ink on paper.
But nowadays it seems almost every car has a satellite navigation device, either included as an option or a portable unit stuck to the windscreen.
Fleets using sat-nav can save fuel through reduced mileage and increase productivity as fewer drivers lose their way. The technology also makes it easier to predict arrival times and plan jobs.
Type in an address or postcode and a husky voice barks directions at you as you travel, accompanied by on-screen directions.
The first satellite-based navigation system was used as long ago as the 1960s by the US military, but could only get a fix four to six times a day. Modern systems use a signal broadcast by the satellite that contains its position and the precise time of transmission. The receiver compares the time of the broadcast with the time of reception, so measuring the distance to the satellite.
When combined with mapping software, sat-nav units can work out their locations in relation to the road network and plot efficient routes.
Many units include Traffic Message Channel (TMC) technology, which delivers traffic and travel information to the driver.
Vehicle tracking
THE days of unreliable delivery times are on the way out. While customers anxious to know the status of their delivery were once told ‘well, he left here a couple of hours ago, he should be there by now’, telematics technology can now locate a vehicle to within a few feet.
Telematics derive from investigations into relationships between telecommunications and computing in the early 1980s. The term generally now refers to automotive telematics, which is becoming a major tool for fleets worldwide.
Combining a GPS receiver with a modem installed in each vehicle, location information is beamed back to the fleet manager’s PC and turned into reports or a visual display using mapping software.
Fleets can thus track vehicles as they travel, plan the most efficient routes via satellite navigation and, if needed, alternative routes to avoid congestion. Arrival times can be accurately estimated and details of further jobs sent directly to the vehicle, or to the driver’s hand-held PC.
Hydrogen fuel cells
WITH a finite amount of oil left in the world, scientists are already well advanced with plans for what to do when it finally runs out – and the future at present revolves around the hydrogen fuel cell.
Vehicles which run on fuel cells already exist – Ikea is currently evaluating an Opel Zafira powered by hydrogen in Germany – but at present they are hideously expensive. Present estimates are that fleets will begin seriously trialling fuel cell vehicles by 2020.
Fuel cells produce electricity as a result of chemical reactions inside them and are an attractive proposition as they only emit water vapour from the exhaust pipe.
However, there are many hurdles to be surmounted before hydrogen can replace petrol and diesel as the major fuel we use in vehicles. In addition to cost, there are currently durability and reliability problems and at present no refuelling infrastructure exists.
Run-flat tyres
TYRES that stay usable even when punctured are a fairly recent ingression into the mainstream market, but the idea has been around since the 19th century.
Not much happened until the late 1970s, when Dunlop featured a sealant and reinflation device built into the wheel, while Goodyear introduced a ‘self-supporting’ tyre. However, the designs were costly.
In 1994, Chevrolet fitted Goodyear EMT run-flats to the Corvette, with more success. Shortly afterward the technology started appearing on armoured limousines. In 1998 Michelin introduced the PAX, which uses unique tyre bead locks and a solid insert that can support the vehicle’s weight.
By 2002, Goodyear, Pirelli and Sumitomo had joined forces to produce new PAX designs.
In the same year, Bridgestone and Continental teamed up to develop new tyres using their respective SSR and Conti Safety Ring technology.
Several major manufacturers use run-flats as standard but cost and availability make them scarce at present. This could change in the future though.
For fleets keen to avoid blow-outs and resultant repair bills, run-flat tyres are an increasingly attractive proposition.
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