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Diesel, The Fuel of the Future?

The diesel revolution in South Africa has seen an increasing number of motorists turning away from fossil fuel and opting for diesel power. The trend triggered initially as a way of buying cheaper fuel, has now spawned a generation of motorists that love diesel for the fuel consumption it returns, and the power that diesel engines offer drivers.

“It’s no coincidence that many motorists have turned away from petrol to diesel as their fuel of choice. For financially hard-pressed South African drivers, the incentive has usually been felt in wallets and purses. The efficiency of diesel as a fuel and the smooth delivery of power through turbochargers in sophisticated power plants has created thousands of diesel fans and growing sales of diesel vehicles,” says Hugo Grobler, National Franchise Manager at ADCO, one of South Africa’s leading franchised providers of diesel fuel injection and related services

A 16cyl in-line Diesel Pump at the ADCO Facility

Many motorists are, however, not aware of the other benefits that diesel will offer for years to come. Some of the generally unknown facts regarding diesel are:

  • Diesel fuel is not only used to create the combustion inside the engine, but it is also used to lubricate the moving components inside the fuel injection system.  It is therefore vital, that only clean diesel is ever used to fill your vehicle’s fuel tank.
  • Building on this fact, ADCO advises that tanks should preferably be filled at busy garages where diesel is regularly pumped. This is because diesel is ‘hydroscopic’ and over time, will naturally absorb moisture from the atmosphere and thus, negatively impact the lubricating properties of the fuel.
  • Diesel fuel injection, much like an electriacian, motor mechanic and diesel mechanic, is a specialist trade all on its own, and requires hilghly specialized and expensive equipment to get the calibration of diesel fuel injection components doen correctly.
  • A petrol engine uses a spark plug to ignite fuel inside the cylinder and is thus called a spark ignition engine. Diesel engines are compression ignition engines, which means that  a diesel engine uses a much higher compression ratio within the cylinder to heat the air inside. When the fuel is injected at high pressures into the compressed air, it ignites without a spark plug. We get a much more complete combustion as a lot more of the injected fuel is burnt in this manner, therefore creating a greater efficiency from the fuel.
  • Sulphur, one of the polluting ingredients, in diesel engines, has been much reduced from about 500 parts per million(ppm) to 50ppm. In Europe, this level is only 10ppm.
  • It’s also no surprise that some of the world’s most prestigious sports car events, such as the 24 hours at Le Mans, was dominated by diesel powered vehicles in recent years. They are more fuel-efficient than their petrol-powered cousins.
  • Diesel is also the choice of 4 x 4 drivers as diesel delivers torque (Pulling Power) far lower in the engines rev range, meaning that a 4 x 4 can power over obstacles at low speed.

Almost 50% of all cars sold are diesel-powered

“Besides these basic attributes, research by an independent authority showed that in 2018 that although diesel-driven vehicles are more expensive to buy, that over a 100 000km cycle that running costs for a large SUV (diesel versus petrol of the same capacity and from the same brand) will be about R 86 000 less,” says Grobler.

“With a leading brand of 4 x4 over a similar mileage, the diesel can cost a whopping R 1 142 045 less to run. Of course, there are many ways of slicing a statistical cake. Turbo-driven diesel sports cars can use more fuel, but this could be accounted for by the fact that these drivers adopt a more aggressive driving approach.”

“Where diesel comes into its own is when it is used in compact city cars. Most recently, a 1.5 litre, turbo-driven compact returned figures of 3.3 l/100km, making it the most fuel-efficient vehicle available in South Africa during 2019.“

“Adding to the appeal of these small powerplants is the use of turbochargers. These significantly boost power without adding a lot of weight. The turbo uses the exhaust flow from the engine to spin a turbine, which it turn spins an air pump. The turbine can spin at speeds of up to 150 000 revolutions a minute significantly boosting engine power,” says Grobler.

“Electric cars may be the wave of the future, but the chances are that the move from many South African motorists from petrol to diesel noted by the National Association of Automobile Manufacturers(NAAMSA) will continue. Almost 33% of vehicles sold since 2016, the body says, has been to motorists opting for diesel. In Europe, almost 50% of all cars sold are diesel-powered.”

The benefits of diesel have recently also begun to be appreciated by aircraft builders. Piper introduced a diesel-burning engine in 2015. The rationale behind these developments is that a diesel engine runs cooler than avgas-powered units, improved fuel use and do away with the problems associated with finding suitable avgas in remoter parts of the world.

“Pressure may be increased to have only electric-powered vehicles in the UK by 2045, but diesel is here to stay,” concludes Grobler.

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Tristan Wiggill
Special Features Editor at Business Fleet Africa