Fact-Checking Needed
There are a few obvious errors in TFA:
1)Efficiency - Diesels are more efficient than gasoline engines because of thermodynamics. For a given amount of heat energy released in the cylinder, more mechanical energy is obtained largely because the temperature of the working gas is higher. It has nothing to do with the nature of the fuel except that diesel is less expensive and can ignite at the higher temperatures found in the engine. Diesel fuel would not burn well in a spark-ignited engine with 10:1 compression ratios. Diesel engines have compression ratios near 20:1. The air is heated by compression (as in a bicycle-pump), and the fuel burns as soon as it is injected into the hot air. The expression for the efficiency has a major factor, (1-Texhaust/Tcombustion) where the Ts are the absolute temperatures of the working gas. The higher compression ratio raises the temperature at which stuff happens in a diesel engine.
2)Clatter - The clattering noise of a diesel engine has nothing to do with detonation. It's the noise of the fuel injection system. Typically, hydraulic pressure of the fuel from the pump forces the injector open at the right time in the cycle and this action makes a pronounced click.
3)Burn - diesel engines take in the same amount of air on each cycle and injects a variable amount of fuel into the heated air according to the load. The injection pump controls the amount of fuel by the length of its stroke.
4)Gears - people who drive diesel care about efficiency and more gears helps improve acceleration and efficiency at cruising speed. A diesel engine has a wider range of torque v rpm than gasoline engines simply because of the higher compression ratios and the longer power strokes. Further, a gasoline engine may red-line at 4000 rpm while a diesel engine may red-line at 3000 rpm. High rpm is a great waste of energy in most cases as the viscous forces in the cylinder/lubricants and gas-flows increase as the square of the velocity. The slowest diesel engines are on ships and may exceed 50% efficiency.
Efficiency of diesel is not just about consumption of fuel and work done. Diesel engines last about twice as long as a gasoline engine, saving fuel, manufacturing costs, and many other energy consumptions around the planet. TFA should have mentioned that the NOx problem exists in all engines but is worse in diesel engines because of the higher temperatures. Many manufacturers inject urea into the exhaust to decompose the NOx. VW opted to cheat on tests instead. They still make fine cars and I would not hesitate to buy a diesel Jetta or wagon. They manufacture a light truck in Asia/Pacific which I would like to have: efficient, geared for efficiency rather than pulling tree stumps... The real problem here is the bad rep of diesel engines. This situation will not help that and the world will continue burning more fuel as gasoline instead of diesel as a result.
The right way to use a diesel engine in a car is as a hybrid. These ~2L diesels can be run at optimal efficiency instead of being chained by gears to the wheels. They would perform better in city and highway driving.
Biting the hand that feeds IT
