Friday, July 29, 2011

Diesel engines: some taboos still around it

Since the 80's, there is no diesel-powered sedan from any American automaker in the domestic market. Often, the experience with Oldsmobile Diesel engines used by GM is blamed for the bad reputation diesels still hold there, due to the absence of a water separator filter on the fuel lines and some head gasket issues, but actually the biggest problem were the mechanics more used to service regular gasoline-powered vehicles. However, this is going to change. The world-acclaimed Chevrolet Cruze is scheduled to be offered with a 2.0L turbodiesel in the U.S. domestic market. Already offered in other countries, it's even the only engine option for the model in India. Actually, since it has a better low-end torque, would even be more pleasurable to the average American driver than its gasoline-powered counterparts.

One of the taboos about diesels is related to the maintenance: it's actually not so harder as most people think. Due to the absence of an electric ignition system, they're even simpler to work on. And currently with all that electronic engine management systems all-around, their fuel injection hardwares are getting closer to the a gasoline/E85/CNG/LPG setup, easing the first contacts for mechanics unexperienced on the diesel field.

Another taboo is about their noise, vibration and harshness. OK, they're quite louder than a gasser, and it's perfectly normal due to their compression-ignition. The same phenomenon can happen in a gasser in an unintentional way when a lower quality fuel is used, leading to the pre-ignition. As far as vibration goes, counterbalancing shafts and different designs on the engine mounting brackets and cushions are reducing this issue and its effects over the riding comfort.

Other incorrect image about diesels is related to pollution: they're reported to pollute more than its gasoline-powered counterparts, but it's actually not true. While there is a dark, thick smoke, out of the exhaust pipe on some diesel-powered vehicles, due to the so-called particulate matter, it's related to incorrect tuning, with a higher amount of fuel being injected and then released unburnt or incorrectly burnt. Nowadays with all that electronic management, injection setups can self-correct the injected fuel amount nearly instantly, leading to a higher reduction on the particulate matter formation, and the evolutions on the exhaust aftertreatment have been helping considerably too. Diesel-cycle combustion proccess is more efficient, then cleaner, and they have the capability to handle a wide range of alternative fuels such as biodiesel, waste vegetable cooking oil or even the nowadays acclaimed ethanol. Dr. Rudolf Diesel himself used peanut oil in his initial trials with a reliable, safe and economically viable compression-ignition engine, and suggested it could even help to improve the economy in agricultural regions, allowing farmers to be self-sufficient on fuel to run their agricultural machinery.

Safety is another thing to consider when opting for a diesel-powered vehicle. Diesel fuel is less volatile than gasoline and ethanol, then reduces the risk of an explosion or a fire. No wonder they're so widely used by military forces worldwide as a NATO standard.

There is also the energy safety: since diesels can use a wider range of alternative fuels, it would lead to a reduction on the dependance on imported oil. And some of the money sent overseas for oil is even used to sponsor terrorist acts in the Uncle Sam's lands...

So, even being still a taboo, light-duty diesels are a great option for the American market.


  1. The older Pontiac Trans Sport minivans had a small diesel engine never available for the domestic market, supplied from Peugeot.

  2. Chevrolet has another nice turbodiesel engine for India, that 3-cylindre 1.0L fitted into the Spark (they call it Beat there). That's even good option to fit into an Aveo.


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