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Reasons for Diesel Engines

12 APR 2013
Career Path : Mechanic

Many of us might associate diesel with the sooty pollution of transport trucks but there’s an interesting history and optimistic future for the compression-ignition engine. The diesel engine is the most efficient power plant among existing internal combustion engines and ExxonMobil predicts that it will surpass gasoline as the number one global transportation fuel by 2020. Diesel engines are found in most heavy-duty trucks, urban buses and industrial equipment, but also in many European luxury cars, including Mercedes-Benz, Audi and BMW.


New Diesel Models Coming

This year, diesel models appealing to the car-buying majority will be introduced by many manufacturers who have previously stuck to gasoline varieties. General Motors relegated diesel to pickup trucks after some 1970’s car failures but are jumping back on the bandwagon with this summer’s Chevrolet Cruze Clean Turbo Diesel model. Japanese carmakers are just as capable as the Europeans in building quality diesels but the 2014 Mazda6 will be the first to crack the U.S. market, featuring a new engine with the lowest compression ratio of any diesel in the world and a variable exhaust valve lift to more quickly circulate engine warming gases.


The Diesel Appeal

The appeal of diesel comes from the fuel efficiency found from burning at a much higher temperature than a typical gasoline engine. Improved fuel combustion means better energy density and as much as 30 percent better efficiency. Submarines adopted diesel before World War I, due to low flammability and vapour pressure and the absence of carbon monoxide in its exhaust. Students at dispatch school may know of the endurance and torque benefits of diesel engines, which has long made them the popular choice in transportation operations.


Their reputation as air pollutants is changing with developments in near-zero emission varieties, and older engines already in service are being retrofitted with clean diesel technologies. The new generation of diesels are quieter and compliant with the world’s most stringent emission standards. To meet future greenhouse gas and fuel economy requirements, new technologies are being developed that will improve vehicle efficiency even further, including low temperature combustion, waste heat recovery and powertrain electrification.


Looking Ahead

The relative shift away from motor gasoline to diesel will be driven by growth in commercial transportation and improving light-duty vehicle fuel economy. Huge diesel growth is expected in aviation and marine vehicles and heavy-duty trucks, particularly in developing nations. As electric cars become more attractive to the common buyer and some large trucking companies convert to natural gas, the long-term outlook for diesel is uncertain but its time is now. Diesels and hybrid cars offer near equivalent fuel economy and pricing. The relative success of the newest diesel vehicles arriving to market will help determine how many more we’ll see in the coming years but in any case, Rudolf Diesel’s most famous invention will be of increasing relevance to those in automotive careers.



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