Diesels Challenge Gasoline Engines

by: John Hartley


DIESELS are still gaining popularity in Europe, thanks to low gas mileage and good performance. The latest diesel cars can take on gasoline engined cars and come out on top!

All turbocharged diesels generate much more torque than gasoline engines, so you get better mid-range acceleration. In other words, from, say, 40-80 mph, a good diesel will see off a good gasoline engine car of the same apparent performance.

Jaguar has introduced a special version of a V-6 2.7 liter diesel that has been developed in Europe jointly by Ford and Peugeot. This is the most advanced diesel around at present, with the brand-new piezo-electric injector operation, the latest common rail injection system and twin turbochargers.

PIEZO-ELECTRIC INJECTORS

What are piezo-electric injectors? Cunning little ceramic devices, and when an electric current is applied they produce a pressure, and so can be used to force fuel into the cylinders. The thing is that they can be operated four times faster than other electro-mechanical injectors so the injector can be opened and closed incredibly quickly. Also, the amount of movement is very small, and you get less noise that you get from mechanical injectors.

Like I said, very cunning, and they all go with high pressure injection to give high power, low noise, emissions and gas mileage. It's developments like these that mean we'll have some diesels in Fast-Autos soon - but not a lot!

As a result, the fuel is injected at horrendously high pressures with incredible accuracy. The result? Masses of power, and almost no smoke, the weakness of old-fashioned oil burners, like the dreadful engines GM introduced about 20 years ago.

This new Jaguar S-Type diesel, develops 206 bhp so it lives up to the Jaguar tradition of high performance. Maximum torque is 320 lb ft (430 Nm) which is more than the 4.2 liter gasoline engine can manage without a turbocharger. Although performance is not sensational, it is definitely not what you'd expect from a diesel.

The Jag diesel will push the S-Type automatic up to 60 mph in about 8 seconds, and top speed is 140 mph. You'll get the idea that Jag regards this as a sporty engine from the fact that it has a six-speed manual or automatic box - both are supplied by ZF. Of course, the most powerful S-Type is the S-Type R [ http://www.fast-autos.com/jaguar_s-type_r.html ].

BMW HAS AN EVEN MORE POWERFUL DIESEL

BMW is also ready with a very powerful 3.0 liter diesel engine which turns out 272 bhp, which would be considered very nice thank you from most makers of 3.0 liter gasoline engines - Ford's top version of its nice 3.0 liter V-6 develops 225 bhp. BMW uses twin-stage turbocharging to get this much power. In this system, one small turbocharger provides power at low speeds, and a bigger turbo is matched to high speed requirement. It is switched in when the speed and load increase sufficiently, and so can generate as much power as a gasoline engine of the same size.

If that is not enough power consider the latest news. Audi is racing diesel-powered cars at the Le Mans 24-hour race! These V-12 engines develop more than 600 bhp, and will challenge the best gasoline engined sports-racing cars.


About The Author

John Hartley is editor of http://www.fast-autos.com, an online magazine devoted to fast cars and supercars. He has written from many of the world's top auto magazines, and has written about 10 books about cars and the auto industry, including 'Suspension and Steering Q&A' and 'The Electronics Revolution in the Motor Industry'. He has been writing about fast cars and testing them for over 20 years, and has been involved in race car design, and has also raced small sports cars and sedans.