Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

Hybrid Diesels?

SylviaSylvia Posts: 1,636
Are they in our future? How will they perform? What will the emission factors be?


  • daysailerdaysailer Posts: 720
    in another thread, a discussion of economy, fuel or otherwise, in a $58K vehicle is pointless, if not ludicrous.
  • stevedebistevedebi LAPosts: 4,098
    Oh, so it is not important for an expensive vehicle to get high MPG?
  • sebring95sebring95 Posts: 3,238
    how's it ludicrous? It's not like there's other $58k SUV's that are performing better and getting anywhere near the fuel economy.

    You said At present, diesels in the USA are merely another example of vehicles which offer improved fuel economy at the expense of performance

    The new mercedes CDI is also another example. Better performance and much better fuel economy than the gas counterpart.

    I think the current breed of Hybrids sacrifice more performance for the sake of fuel economy than the current diesels. So far the Prius is slower and more expensive than a TDI. Mileage depends on who you're talking to. We'll see what happens with the next round of V6 Hybrids, but I suspect a diesel hybrid would give similar/better performance and better mpg.
  • dhanleydhanley Posts: 1,531
    The mercedes grand sport is a hybrid diesel, and very attractive--v8, 6-seater, 0-60 in sub 7, and good fuel economy.

    Saying that fuel economy is "pointless" in a 58K vechicle assumes that only cost is a factor, which is VERY not true. I care a lot about fuel economy for many reasons, environment, dependence, politics, and a future when the oil runs out. I am of the opinion that people are not going to give up size and power until the oil coming out of the ground slows to a trickle, so we need to find ways to provide that while preserving our resources as best we can.

  • Hey there is Toyota Volta with 400h V6 HSDdrivetrain, 3 seater, 0-60 in less than 4 sec and 40+mpg. Can Diesel beat that? A hybrid diesel will be interesting because there are more energy in the fuel.

  • dhanleydhanley Posts: 1,531
    Otherwise, why are you posting it here?
  • "why are you posting it here?"

    Well, how about to see where hybrid diesel stand against hybrid gas? You sound like a sore person from looking at your other posts. I don't want to ruin this thread because there are so much to discuss regarding how much benefit diesel can get if combined with electric vs. gas electric. If it is not welcome here then, have a great discussion in this thread.

  • dhanleydhanley Posts: 1,531
    There's other hybrid vs diesel threads, so, thanks.
  • dhanleydhanley Posts: 1,531
    I wonder if one of those would fit under my hood??

    There's a pretty good reason there hasn't been as many hybrid diesel cars produced. The gains to be had are less. Diesels are already throttle-free and lean-burn, so for one thing moving from a 2.0L to a 3.0L doesn't hurt efficiency as much as with a gas engine, and a smaller lean-burn engine is one of the reasons for moving to a hybrid.

    Of course, there's regenerative braking and other efficiencies to be had but with the GrandSport, the hybrid makes the diesel 20% more efficient, which is not the same gain as a gas engine gets ( although the net efficiency is still higher ).
  • robertsmxrobertsmx Posts: 5,525
    It would definitely take a lot of space to put a 3200 HP diesel engine in a car, hybrid or not. :-)

    There have been some diesel-electric prototypes, but I wouldn’t bet against seeing a production diesel-electric car soon. It might come from Honda of all places. The limiting factor may be the bulk of diesel engines themselves.

    If Honda installs an electric motor, twice as powerful as that in the Civic Hybrid (30 HP @ 2500 to 4000 rpm, 75 lb.-ft @ 1000-2500 rpm), to go with its 2.2-liter CTD-I engine current used in European Accord (140 HP @ 4000 rpm, 245 lb.-ft @ 2000 rpm), the power train would deliver 170 HP / 310+ lb.-ft, while improving upon the mileage that the CTD-I already does (rated 52 mpg mixed driving in UK) and definitely improving emissions (smog/green house) with the added benefits of idle stop and regenerative braking etc.

    Sure, it would be possible to add displacement to the 2.2-liter engine to get that kind of power, but in the process, emissions will go up, and mileage will go down. And then, another aspect that electric power brings is replacing the current mechanical AWD system (while adding power). That’s an area I want to see hybrids touch in a big way.

    Lotus had plans of creating a sports car using diesel-electric hybrid power train, not sure if they are going with it or not.
  • akjbmwakjbmw Posts: 231
    Next time you go to the airport, look closely at the tractors that move the planes around.
    Just need a battery bank to store the kinetic energy when you have to stop faster than coasting gradually.
  • gagricegagrice San DiegoPosts: 31,111
    I found this an interesting bit of hybrid information. GM has already delivered diesel hybrid buses to transit systems.

    "Consumer-based tax credits will play a critical role in gaining market acceptance by making these technologies more affordable."

    This is to offset the thousands of dollars more per vehicle cost for consumer vehicles.

    What are the tax credits now on the hybrids? - line.html
  • The Seattle Hybrid buses were very expensive, at $600,000 a pop, vs 200,000 plus change for the regular non-hybrid diesel buses. they had all kinds of subsidies from the govt,

    Seattle hopes they will save 700,000 gallons of diesel fuel a year. (a fleet of 250 buses, if i remember right)

    This is still to be seen, but it is true that the most efficient hybrids are diesel-electrics. And not just buses, cars and light trucks.
  • gagricegagrice San DiegoPosts: 31,111
    That is a chunk of change. It looks like you and I will subsidize the clean air in Kent WA. I wonder what the difference in cost and efficiency between the hybrid diesel bus and the CNG/LNG. I think that is what the buses in San Diego use.
  • moparbadmoparbad Posts: 3,868
    Were subsizing the current hybrids with tax deductions, also the current large SUV's.
  • rfruthrfruth Posts: 630
    Wow Chrysler is going to crank out 100 of them - snip - Consumers looking for hybrid pickups at dealerships selling Chrysler group or General Motors brands will have a hard time finding them. Dodge will build just 100 diesel-electric 2005 Ram pickups. The division will sell them to fleet customers such as utility companies. None will be available to consumers this year or next - and the trucks may never be available to the general public, says Frank Klegon, Chrysler group's vice president of product development process and components.
  • amazonamazon Posts: 293
    A diesel engine ususlly performs very well in highway driving (constant RPM), whereas the electric hybrid solution helps in stop and go driving. These two could complement each other very nicely.
  • "A diesel engine ususlly performs very well in highway driving (constant RPM), "

    So can a gas engine with different(Atkinson) cycle. Diesel engines are heavier and more expensive than gas engines. Stop/restart of diesel engine during stop-and-idle-and-go traffic would be difficult due to the heavy engine and the lack of spark plug.

    For those reasons, Atkinson cycle gas engine makes more economical and engineering sense. Diesel would be a very good choice thought, just not the best choice.

  • amazonamazon Posts: 293
    The only thing is that the Diesel is tried and true, whereas the Atkinson is not.
  • "The only thing is that the Diesel is tried and true, whereas the Atkinson is not"

    The main difference between "regular" Otto cycle and Atkinson cycle is difference in timing of closing intake and exhaust valves. Pretty much like VVT-i or VTEC.

    Prius has been on the road for 7 years, since 1997. It is a Toyota and even Lexus is going to use it. By looking at reliability records of both companies, I wouldn't say the cars that they build are not "tried and true".

  • zodiac2004zodiac2004 Posts: 471
    Also, the diesel can perform adequately in case of battery failure, while the Atkinson engine cannot. And there is very little to be gained by stopping and starting the diesel, since when idling under no load, the diesel engine consumes VERY little fuel.
  • "Also, the diesel can perform adequately in case of battery failure, while the Atkinson engine cannot."

    The way PSD is set up, as long as Atkinson cycle ICE is moving, electricity is being generated. The battery isn't necessary for spark plug to ignite.

    "And there is very little to be gained by stopping and starting the diesel"

    Yup, that's why diesel and electric hybrid have overlapping benefits but both increase price. That's when "price for benefits" comes into question.

  • john1701ajohn1701a Posts: 1,897
    > the diesel engine consumes VERY little fuel.

    I've heard that LAME argument many times now.

    It has no basis in reality, since there is no data to support it. The data actually shows that diesel engines suffer in low-idle conditions (like everyday commute traffic)... compared to not running a gas engine at all, like what Prius does.

  • gagricegagrice San DiegoPosts: 31,111
    Diesel engines work efficiently at a constant rpm. I don't think they would be acceptable in a vehicle design like the Prius. Maybe a straight generator to keep batteries at float and use electric drive. Then you have the engine noise problem that is not present in the Prius. I think diesel engines are at their best in vehicles that are currently available such as the MB CDI and VW TDI.
  • john1701ajohn1701a Posts: 1,897
    There is a possibility that when the "hybrid hybrid" emerges, the diesel engine could play a role. That system would use both battery-modules & ultra-capacitors and would rely more heavily on electricity for propulsion. The engine would be even smaller then.

  • sebring95sebring95 Posts: 3,238
    > the diesel engine consumes VERY little fuel.

    I've heard that LAME argument many times now.

    It has no basis in reality, since there is no data to support it.

    Huh? What's lame about it? A diesel uses very little fuel when idling, that's a fact. Would it be worth implementing features that turn the diesel engine off? Maybe, maybe not that would have to be determined.

    I actually did some testing yesterday with my VAGCOM software. I logged and monitored rpms, speed, throttle demand, and fuel qty. I haven't had a chance to really look at the data yet, but I'm trying to compare speeds vs fuel burn to see if there's a sweat spot in the TDI. (is 75mph vs 80mph exponentially worse than 70mph vs 75mph, etc).

    At idle here are fuel burn levels:

    Idling in neutral no accessories: .5 L/hour (.1321 gallons/hour)

    Idling in neutral with A/C: .9 L/hour (.2378 gallons/hour)

    I basically can idle with the A/C running for over 60 hours on a full tank of fuel.
  • djasonwdjasonw Posts: 624
    Perhaps that's SMALL for one vehicle. You have to look at the picture for ALL cars. Imagine if ALL cars shutdown at idle. First off, imagine how much less noise and pollution there would be. Secondly, the impact on fuel savings alone would be quite measurable.
  • sebring95sebring95 Posts: 3,238
    Secondly, the impact on fuel savings alone would be quite measurable.

    That's what would have to be determined. If it costs $1,000 to add this to a diesel, is there really benefits in the end? Maybe, maybe not as I stated above. Worst case, say I commute 300 days a year and am stuck idling 1/2 hour per day. I'd burn an extra 36 gallons per year. That'd take 15 years to recoup the savings, and according to John vehicles don't last half that long anyway, lol. Of course someone like myself, I drive 80-100 miles per day and rarely idle.
  • djasonwdjasonw Posts: 624
    Let's not think think of dollars and think of our environment. Using your calculation of 36 gallons per year we can multiply that by 5,000,000. That is assuming LESS than 1/3 of new cars have auto shutdown restart. They all won't be diesels so fuel burn will be higher. Now we're talking 180,000,000 LESS gallons of fuel per year. That has to impact air quality, don't you think??? If we really calculated ALL the cars on the road today and the fuel they burn while idling, it would be staggering. I feel quite honored I am contributing to less pollution driving my Prius.
This discussion has been closed.