Why not invest in some R&D and give diesel a second chance?

After all, diesel vehicles are more fuel efficient. Diesel-electric hybrids, even more.

6 Answers

  • 3 years ago
    Favorite Answer

    Amazingly, efficiencies of diesel-electric hybrids are not very different from gas-electric hybrids. The reason lies in thermodynamics. Diesel engines are deemed to introduce heat at constant pressure because of the finite injection time; otto cycle engines like gas car engines introduce heat at constant volume (much quicker burn time). That makes the theoretical maximum efficiency of diesel engines with infinite compression ratio 50% and the theoretical maximum efficiency of gas engines about 65%. Gasoline engines can't reach the practical pressures that diesels do so in the real world diesels often enjoy better efficiency than gas engines do. Toyota uses Miller valve timing (not available in diesels) to raise efficiency of the Prius engine above 40%, leaving very little room for diesels to improve it.

    In the end, diesels are falling out of favor because of emissions. They were given a pass on particulates for many years but now we have learned just how bad the particulates are. They are well controlled by diesel particulate filters but at a shocking price - replacing a DPF, which can happen within 100K miles, can cost $8000. Added to the difficulty of decently controlling NOx it makes diesels look like risky investments. The scandal of no less an automaker than VW essentially admitting the only way to pass emissions is to cheat really underlines that risk. Who is going to tell their investors they have better brains than VW? The timing could not have been worse.

    I expect there are small labs within most auto makers looking for the magic key to clean diesel power. If one of them finds the magic key that manufacturer will have a huge lead.

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  • 3 years ago

    Some reason can always be found to invest in a thing: "why not spend on some infrastructure and start using horses for transportation. After all they are more environmentally friendly...?" So just having a reason is not quite as good as a broader understanding.

    When it comes to vehicles our four concerns and reasons for buying are 1. Money, 2. appearance, 3 environmental concerns 4. strategic availability/usability. From a countrywide/ military or corporate perspective you can subtract appearance somewhat.

    You can make any car look like any other on the outside so diesels would be fine here. Financially a diesel is more expensive than gasoline models but less costly than electrics due to economies of scale and existing infrastructure. Going forward it is likely electrics will catch up. Diesels last longer than gasoline cars but no where near as long as an electric motor and with far more maintenance.

    We want to know that we have available sources of fuel to operate our vehicles going forward. The US has lots more petrochemicals than we once thought, but newer sources are expensive to extract and their energy return on energy invested is very low. Tar sands are not even economical when oil prices are as low as at present and production stops. This takes us back to importing oil from overseas. Oil companies must lie, cheat, bribe and seize public and private land in order to extract it and get it to market. And all the time scientists are telling us that we must reduce our fossil fuel use to zero. Regardless of your beliefs this is a volatile political situation that does not suggest a strategically secureplan. This also suggests a very risky investment platform for technologies like diesel engines that depend upon this fuel..

    Environmentally a diesel is slightly more efficient than a gasoline car, but a hydrogen fuel cell electric car is slightly more efficient still and a battery electric car is about 2 to 3 times as efficient. The BEV so outclasses the diesel or even the diesel hybrid in efficiency that it becomes a non-issue. But efficiency is only really important if your fuel is polluting. Electric cars are able to convert clean renewable fuel into transportation miles. This is a trick no R & D investment in Diesel will allow us to pull off. So moving to a cleaner world diesel represents a dead end. Should we invest money into a dead end?

    Some will say that diesel is a bridge fuel and is taking us in the right direction. A dead end can be taking us in the "right direction." Should we waste our time going down what we know is a dead end just to see how far it can take us? In a world where we must reduce our use of fossil fuels to zero, this would be an investment that is not helping us. In fact, it is hurting us by wasting crucial time.

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    • Hydrogen for a FCEV, with today's technology is made from fossil fuels, primarily Ngas. Compressing or liquefying it requires lots of energy. It is better for rockets which demand a high energy density by weight but not so good for cars because of its very low energy density by volume.

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  • Anonymous
    3 years ago

    I love my diesel car! It's my second favorite after my electric car.

    Diesel does have many advantages over gasoline. Better efficiency is one of them. But there are some technical challenges to get the emissions up.

    Back when emissions regulations were just starting to become enacted, diesel engines actually produced less emissions than gasoline engines. The ultra lean burn and super high compression ratios in a diesel helps reduce carbon monoxide, unburned hydrocarbons as well as volatile organic compounds and even oxides of nitrogen.

    However, the main problem is oxides of nitrogen emissions reduction. Gasoline engines can run at a stoichiometric air/fuel ratio which helps three way catalytic converters reduce NOx. But this isn't the case for a diesel.

    Water injection may help. Or if there were some way to filter all the nitrogen out of the air... Anyhow, diesels are still popular on large vehicles. The trick is getting them on smaller vehicles and passing emissions.

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  • 3 years ago

    I know small diesel cars are popular in Europe. I also know a diesel engine is much more expensive that a gas powered engine. I guess auto manufacturers in the free market have decided the investment is not worth the the money. Maybe some small start up will prove them all wrong.

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  • 3 years ago

    Diesels are in common use in Europe and are clean. Diesels were demonized in America by the environmentalists fifty years ago and they pretty much eliminated it's use in passenger vehicles forever.

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  • C L S
    Lv 6
    3 years ago

    Too late 'old boy' many, many years of expert investigation is now passed and failed completely.

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