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Hybrid Diesels?

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Comments

  • robertsmxrobertsmx Posts: 5,525
    Are you trying to tell me that 1000 hp in a freightliner would eliminate the need for all those gears?
    Not all, but you could definitely eliminate some of the gears with twice the power! Here is how it will affect the picture.

    To pull the same load, you could now use twice as tall gearing as earlier, and could pull to (twice as much) greater speeds in each gear, and could allow you to cut the gears in half. This assumes that there has been no increase in engine's revability, it still operates in the narrow power band.

    In case of increased revability, you could retain the shorter gearing, and manage to extract greater speed in each gear.

    Thats how HP helps, and that is no "little impact".
  • qbrozenqbrozen Posts: 24,630
    The fact is, no matter how much HP you get out of that engine, you HAVE to stick with the gearing as is. Its basically the same reason why any real off-road vehicle has a transfer case with a 4-low option - to give you the most power with the most traction possible. You COULD use the higher gear, but all you will do is spin your wheels and bury yourself up to the doors. If you were to raise the HP and gearing of a rig, the only thing you will do is burn up the clutch and/or tires while trying to get 30 tons moving. Again, the lower gearing is there because you are moving such a large mass. If you try to get that thing moving at a faster rate, you will just break something. Its just like a hernia - if you try to clean and jerk 400 pounds at break-neck speed, you are going to hurt yourself and you won't get the job done.

    '18 Stelvio Ti; '67 Coronet R/T; '14 Town&Country Limited; '09 LR2 HSE. 45-car history and counting!

  • marcbmarcb Posts: 152
    diesel hybrid design has lower impact in the energy lifecycle:

    http://www.greencarcongress.com/2004/09/whatrsquos_the_.html
  • robertsmxrobertsmx Posts: 5,525
    The fact is, no matter how much HP you get out of that engine, you HAVE to stick with the gearing as is.

    NO. You don’t HAVE to. Gearing serves as a balancing act between thrust that would be needed to pull load, and speed. HP is the representative of the combination of these two.
  • qbrozenqbrozen Posts: 24,630
    So you are still saying that you feel a 1500 HP Kenworth loaded to 60K pounds could start off in 3rd gear without a problem? And then skip shift to 6th, etc? And your belief is that this will be just fine? You think the clutch will stand up to that? And you won't smoke the tires into the ground while the load stands still? I just want to be clear that this is what you are saying.

    '18 Stelvio Ti; '67 Coronet R/T; '14 Town&Country Limited; '09 LR2 HSE. 45-car history and counting!

  • robertsmxrobertsmx Posts: 5,525
    Give me numbers, and I will back up everything I have suggested. It is not based on beliefs, it is based on raw definition of… HP.

    I think you need illustrations. You can go ahead and provide me some data, and I will elaborate on it, or I will come up with something for the same (as soon as I have enough time to do it).
  • qbrozenqbrozen Posts: 24,630
    ah, but that's the problem with looking at sheer numbers, definitions, and equations, they fail to take reality into consideration. Yes, I can plug a higher HP number into an equation (the definition you mention being 1 HP equals 33K lbs/ft/min) and come out with a better rate of acceleration; however, this only works in a vacuum. Unfortunately, rigs do not operate in a vacuum independent of their other systems and forces of gravity. Given no variables, equations work. But the vehicle's clutch, tires, and even driver are all variables that an equation does not account for. By the sheer numbers, you can give a rig 5000 HP and 5000 ft/lbs torque and haul 50 tons from 0-100 in jet car time, but the limits of traction and drivetrain durability contradict the numbers.

    '18 Stelvio Ti; '67 Coronet R/T; '14 Town&Country Limited; '09 LR2 HSE. 45-car history and counting!

  • I am no expert, but isn't the need for 18 gears comes from the ultra-narrow operating RPM range of the big-rig diesels.

    If the engine operates only between 1700 to 2100 rpm, gearing is the only way you can control speed. If the engine can operate between say 1700 to 5000 rpm, it wouldn't need any more than 5 or 6 gears. The 1st and 18th gear ratios would stay the same, but it'll probably need only 4 ratios inbetween
  • qbrozenqbrozen Posts: 24,630
    yes, we mentioned the low redline a few times, so no disagreement there.

    but, just to correct, it doesn't "only operate between 1700 and 2100." Its from idle to about 3K. And, yes, if you could change the redline, you could cut out gears, of course, but that wasn't the issue we were discussing. But maybe eventually manufacturers could develop a way to increase the rotational speed of a diesel without blowing a hole in the vehicle, but it just hasn't happened yet.

    '18 Stelvio Ti; '67 Coronet R/T; '14 Town&Country Limited; '09 LR2 HSE. 45-car history and counting!

  • robertsmxrobertsmx Posts: 5,525
    If definition doesn’t fit the reality, would it make for a valid point? You seem to refuse to accompany changes that can accompany changes in output ratings. Why? Why would you want to keep the same gearing if the power output doubles? That would be an overkill, IMO.

    Let us start from here… and take one step at a time.
    Do you agree that “HP” relates thrust at the wheels to the rate at which the wheel turns? Yes, or No?
  • qbrozenqbrozen Posts: 24,630
    I'm not sure I'm following most of your first paragraph there, but to answer your question about keeping the same gearing - as I've done many times already - its not a matter of a lack of power but a matter of a lack of drivetrain durability and road traction that will prevent you from moving that heavy load any faster off the line.

    To answer the question in your second paragraph, yes.

    let me ask you a question, have you ever done any off-roading with a truck? When you get stuck in a mud pit, you switch your gear to 4-low. Why? And why do professional rock crawlers with supercharged big block engines in their jeeps build their vehicles with the lowest gearing possible?

    '18 Stelvio Ti; '67 Coronet R/T; '14 Town&Country Limited; '09 LR2 HSE. 45-car history and counting!

  • robertsmxrobertsmx Posts: 5,525
    Forget about durability and traction for a moment and focus on impact of power/torques and its use via a transmission. Well, you have agreed to the point that HP does in fact relate thrust (handles traction issue) to vehicle speed.

    Now, if you have twice as much power (at same rpm), why in the world would you want to keep the gearing short if your thrust requirement hasn’t changed? You could now use twice as tall gearing without affecting thrust but doubling your wheel speed! There goes the need for extra gears out the door.

    And discussing off road driving in this context would be digressing from the point.
  • qbrozenqbrozen Posts: 24,630
    oh, well, if we're throwing all reality out the window and just looking at numbers, your point is totally correct. Then again, if traction, drivetrain, and weight have no bearing, you could just start in 18th gear in a rig and not have to shift at all. problem solved.

    '18 Stelvio Ti; '67 Coronet R/T; '14 Town&Country Limited; '09 LR2 HSE. 45-car history and counting!

  • robertsmxrobertsmx Posts: 5,525
    Well you could start the big rid in 18th, if you have enough horses. After all, the big rigs like diesel locomotives don’t employ 20 speed transmission. And thats the reality.
  • f111df111d Posts: 114
    Unfortunatley you have to be registered to read (http://www.autonews.com/news.cms?newsId=10132)
    Thought this might be a good place for this info!

    A study by the Massachusetts Institute of Technology's Laboratory for Energy and the Environment found that even with aggressive research, fuel cell cars won't beat diesel hybrids on total energy use or greenhouse gas emissions by 2020.

    It concluded that intense research on a diesel-engine hybrid could produce by 2020 a vehicle that is twice as efficient and half as polluting as fuel cell cars including the emissions and energy used to deliver the fuel and make the vehicle.
    Paul
  • rfruthrfruth Posts: 630
    You VW / diesel fans must be tickled pink - snip - The Car Connection Daily Edition: Oct. 14, 2004 says " VW Does a 180 on Hybrids - A diesel-electric hybrid prototype may be a hint of what's to come from Volkswagen AG."

    http://www.thecarconnection.com/index.asp?n=173&sid=173&a- - rticle=7654
  • rfruthrfruth Posts: 630
    Or should I say happy as a clam at high tide


    http://www.wired.com/news/autotech/0,2554,65273,00.html
  • gagricegagrice Pahrump, NevadaPosts: 31,432
    I'll be even happier when the vehicles hit our shores. Keep the articles coming. One of these days someone will bring a small diesel or diesel hybrid PU that will get me to part with some of my money. Otherwise nothing on the market excites me to the point of opening my wallet.
  • rfruthrfruth Posts: 630
    Toyota's head of R&D says "a diesel hybrid would be very expensive" - snip -

    Q: What do you think of the possibility of developing diesel hybrids?


    A: If you compare the cost of diesel and gasoline engines, diesel engines are more costly to
    produce. The cost will increase in the future as cleaner diesels are developed. So a diesel hybrid would be very expensive. It would be technically feasible and viable for large commercial vehicles but not for passenger cars because of the cost.
    http://www.detnews.com/2004/autosinsider/0410/24/c04-313133.htm
  • robertsmxrobertsmx Posts: 5,525
    I'm not surprised. Don't diesel require a turbo charger on top of a "regular" engine? Things like that, including weight issues (and trying to bring them down) can also add to the cost.
  • bhill2bhill2 Posts: 1,902
    Hmmm, that's an interesting question. Diesels don't 'require' a turbocharger, lots of diesels haven't had them (including my '81 Rabbit diesel, which was a good example of why you would want one). I think most diesels have them now. But I wonder if one would be needed in a hybrid application. Any thoughts?

    2009 BMW 335i, 2003 Corvette cnv. (RIP 2001 Jaguar XK8 cnv and 1985 MB 380SE [the best of the lot])

  • robertsmxrobertsmx Posts: 5,525
    It should be possible. However, non-turbo diesel will have lower power output.
    1.6-liter diesel engines from VW (1986):
    52 HP @ 4800 rpm, 72 lb.-ft @ 2000 rpm (normally aspirated)
    68 HP @ 4500 rpm, 98 lb.-ft @ 2800 rpm (turbo charged)

    Not sure how they compared in terms of fuel economy and emissions though. In this case, a 15-16 HP electric motor may make the normally aspirated engine only comparable to the turbo charged version in terms of output.
  • qbrozenqbrozen Posts: 24,630
    turbo really isn't that big a part of the cost, though. There are plenty of turbocharged cars out there and manufacturers aren't complaining about the costs on those.

    But, yes, the overall diesel engine is typically more expensive. I would guess this is mostly due to the robustness of it all. I mean, running something like 24:1 compression ratio (i'm pulling that number out of the air, but i believe i'm not too far off) calls for heavy duty parts. Add to that direct injection and some other relatively fancy technologies and you got yourself one expensive engine.

    Now why this has anything to do with hybrid-diesel I don't know. I would tend to think that adding an electric assist to a diesel would tack on the same premium as adding one to a gas engine. Am I missing something?

    '18 Stelvio Ti; '67 Coronet R/T; '14 Town&Country Limited; '09 LR2 HSE. 45-car history and counting!

  • gagricegagrice Pahrump, NevadaPosts: 31,432
    1.6-liter diesel engines from VW (1986):

    All the new diesel engines are far superior to the 1986 versions. I would suspect the reason they say it is too expensive to make diesel/hybrid is the gain is not enough to justify adding the hybrid mechanism. With a gas ICE it adds considerable mileage gain. The diesel is already far superior to the gas engine. The automakers would be ahead of the game to spend that extra money on particulate filters that will gain it access to the states that require the lower emissions. It is already a fact that a smaller sized diesel is equal to the mileage/performance of the existing hybrids. If the emissions can be brought in line the cars will sell for less than the hybrids. VW has just started producing a V6 TDI that meets all the latest European emission standards. It is for sale in the UK in the Touareg and Phaeton. It is a combined 30 mpg engine in vehicles over 2 tons. That is pretty significant IMO.
  • robertsmxrobertsmx Posts: 5,525
    That was supposed to be an example to illustrate difference between turbo versus non-turbo diesel engines, and from the same era (happens to be from the same year).
  • gagricegagrice Pahrump, NevadaPosts: 31,432
    I think the turbo is required to get the efficiency that the current crop of diesels possess. Maybe not in big diesels, I really don't know. All the modern car diesels in Europe are turbo diesels as close as I can tell from my research.

    That is part of the problem the older diesels have given the modern diesel engines a bad rap. Several I can think of I would not have owned. Especially the early GM conversion diesel.

    I just don't see the logic in adding all the hybrid equipment to an ICE that is efficient all by itself. Time will tell who is right on this subject. I doubt we have much say in the process.
  • rfruthrfruth Posts: 630
    Yes time will tell but if we were to speculate (okay a hybrid Durango hasn't seen the light of day) on where the hybrid market will be in 12 months it would go something like this: current hybrids (as of now) about half a dozen with that many more on the way, clean high mileage diesels zero, diesel hybrids zero, hope we're not putting all our eggs in one basket ...
  • "I think the turbo is required to get the efficiency that the current crop of diesels possess"

    Yup. Turbo Diesel also recirculate exhaust gas in order to achieve mpg near HSD hybrids. To meet legal emssion, Diesel need additional particle filter and "special" combustion technique. It sounds crazy but sometimes fuel is added into the exhaust to reduce emission. All those technology add cost as much as adding a hybrid option!

    Furthermore, cleanest modern turbo LSD Diesel emission level isn't low enough to meet current US emission. The only possible way for diesel to exist on US road is to become diesel-electric hybrid. It is not surprising to me that BMW, Mercedes and Porsche are coming out with diesel hybrids. I like Porsche's approach. They are thinking about using 270hp Hybrid Synergy Drive that will be in Highlander Hybrid and RX400H. HSD lowers emission, increases power and fuel efficiency, all at the same time, unlike other assist hybrid types.

    Dennis
  • gagricegagrice Pahrump, NevadaPosts: 31,432
    "Furthermore, cleanest modern turbo LSD Diesel emission level isn't low enough to meet current US emission."

    They don't meet the standards set by CARB which four other states have adopted. They pass the US EPA regulations without a problem even with our lousy diesel in many areas.

    "I like Porsche's approach. They are thinking about using 270hp Hybrid Synergy Drive that will be in Highlander Hybrid and RX400H."

    That is a weblogger's dream. The Porsche Cayenne would give up almost 200 hp if it used the RX400h HSD. What would be the point of having a slow poke Cayenne? The Cayenne is 1500 lbs. heavier than the RX400h. Toyota has nothing in that League.
This discussion has been closed.