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Thread: Hybrid vs. Diesel Debate
02-10-2006, 10:51 PM #101
Hybrid vs. Diesel Debate
Ok, so your intent is good but your understanding of the world is a bit behind. I had the pleasure of driving a sports car for 3 years that would accelerate from 0-60 mph in 7 seconds (that's about 0 - 95 Kph in 7 seconds for you embracers of Gallic imperialism -vs- Anglican imperialism) AND it got much better than 100 mpg (~42 km/l) if you measure consumption from well to wheels (a 30 mpg gasoline car gets about 20 mpg if you look at the whole energy chain from well to wheels - not counting waste during war to defend the oil). It is possible to build an efficient vehicle.
I'll also add that one could use ANY energy source to provide this energy so the assumption of petroleum is simply there to achieve an apples-to-apples comparison.
This performance and economy were possible because of the introduction of an electric motor. Now I don't care how much you tweak, a combustion engine be it diesel, gasoline, turbine, wankel, stirling, etc, you will never get that kind of performance unless you find a way to capture and use the heat lost from the burning in a cheap, moving vehicle. I, of course did assume a stationary co-generation plant for my 100 mpg estimate.
Now that I've briefly brought you into the late 1800's technically, let's look at the economics: Hybrids aren't any more expensive than pure ICE vehicles to manufacture - and they could be made even cheaper than they are today (but that's a different story). There is fundamentally nothing in a Prius that you don't have in your Jetta. It's just that the starter battery is a bit bigger, the starter motor can actually propel the car, and the starter clutch is a bit more sophisticated than would be required just to start an engine. The combustion engine is quite simple and the transmission is much simpler as well.
The reason the Prius is so expensive is that there is so much demand for them in the US that people are willing to wait for 6 months for delivery and pay US$3K over the list price which is already adjusted to recover the R&D costs in a record amount of time. Supply and Demand determine the PRICE of an item (at least in the US).
I can't explain why Europeans are so willing to pay so much for so little when it comes to vehicles and I'll also agree that Americans are equally fickle about paying so much for something so much bigger than they need.
I don't disagree with some of the sentiment's of your wish list but let me take it a bit further:
1) everyone drove at the speed limit; 10-20% reduction;
[(of course, if you drove zero mph, you'd see a 100% reduction but that kind of defeats the purpose of having a vehicle. Slowing down does not improve efficiency. While it reduces consumption, it also reduces output. I'd prefer to find a way to get better efficiency and increase speeds as that will move society along)]
2) if owners of large SUVs traded them in for a station wagon powered by a 1.4 Liter twincharger: 50% reduction per SUV taken off the road;
[(or they could replace their SUV's with strong plugin hybrid wagons -were they available- and achieve better than 500% improvement.)]
3) if every owner of a compact SUV bought an equivalent car instead, about 10-20% reduction;
[(or they could replace their SUV's with strong plugin hybrid cars-were they available- and achieve better than 500% improvement.)]
4) if we switched to diesel, which requires less refining and has a higher BTU content, about 10% overall reduction just from the refining process; [(no argument here between gasoline and diesel but if you added a strong plugin hybrid, you'd see several thousand percent reduction in refining process depending on the energy source, as well as about a 500% increase in the vehicle efficiency)]
5) if people commuted more by mass transit...
[(no argument here but it will take a long time to get the US rebuilt to the point where mass transit works beacuse of so many years of building around the automobile - yep, Europe doesn't hold any monopoly on self-destructive inertia to overcome - we've got problems too)]
Now if you really want to help the planet: Rather than wasting so much effort gushing about how your VW diesel isn't as crappy as everyone elses gasoline car or the minimal hybrids that we've actually been able to squeeze out of a few car companies; instead write letters to your beloved VW to get them out of the 1930's and into the 21st century by selling a plugin hybrid.
Putting down people who have taken a great step towards energy sustainability by purchasing cars that are on the right path, even if they aren't there yet is not helping any of us.
Before diesel can become energy self sufficient, it's economy needs to increase way beyond what traditional engines can do since the planet does not produce enough biomass energy to feed today's consumption. It's going to take some "gee-wiz" technology to seriously reduce our consumption. We need to find a way to implement a 'moores law' for vehicles, similiar to semiconductors. I don't know if you are old enough to remember vacuum tubes but they were not going to get us on a 'moores law' path. Just as we had to replace vacuum tubes with semiconductors, we need to replace combustion engines with electric motors/batteries and then improve the electric motors/batteries. There were die-hards like you who espoused major changes in vacuum technology but they couldn't get on the right improvement curve. There may be other technologies as well that we shouldn't discount but electric is here today and it has been proven to work. The future potential is clear and obvious. We just need to get it into production and on the streets.
I'll leave you with a few simple numbers to remember when comparing combustion engines with electric:
combustion engine: 20 - 25% efficiency
electric motor: 85 - 95% efficiency
Dude: just do the math!
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02-10-2006, 11:16 PM #102
Hybrid vs. Diesel Debate
A couple of points:
"of course, if you drove zero mph, you'd see a 100% reduction but that kind of defeats the purpose of having a vehicle. Slowing down does not improve efficiency. While it reduces consumption, it also reduces output. I'd prefer to find a way to get better efficiency and increase speeds as that will move society along"
Of course going zero will consume zero energy (unless you're one of those people who wastes energy idling). But there is an optimal speed for effiency; aerodynamically, drag increases with the square of speed; above about 50-60 mph, aerodynamic drag becomes the overwhelming consumer of energy; 65 mph works out to a pretty good speed/effiency compromise in most cases and for most 1-2 hour journeys won't slow you down more than 5-15 min overall compared to going, say, 75 mph (especially as average speed is usually much lower in both cases). And drag will drain the battery faster on a plug-in too.
As for plug-ins: what is the fuel source for the electricity (in the US coal no doubt is a large chunk of it); what is the efficiency of converting coal to heat to allow water to become steam and run a turbogenerator set? What is the effiency for nuclear? What are the overall enviromnental effects of nuclear? What about hydroelectricity which floods vast areas with known climatic and environmental effects? What is the distribution efficiency of electricty? (hint, transformers on transmission lines need cooling to dissipate waste heat). How much energy is lost pushing enough energy down to your car's plug to charge its batteries? What effect on the power grid will millions of people charging their cars overnight have? Finally, how much do you pay for electricity in your area?
We need to look at the big picture. It is not a zero-sum game.
02-11-2006, 04:55 AM #103
Hybrid vs. Diesel Debate
Now we're getting down to the real issues!!! I appreciate that you've been giving it some thought.
You're right about the drag issue with speed, however, I still contend that we must move around. The magic 55 mph really isn't really that magic of a number but it does represent the knee of the curve for the average car design. I'll remind you that with pure EV's, one does not need as much frontal radiator area for cooling off all the waste heat, therefore one can incorporate slightly (but only slightly) better aero design. My EV1 had a drag coeficient of 0.19 which was pretty awesome (I think the Prius is around 0.26 - someone please correct me if I'm off) but even so, It got a lot further range at 40 mph than 55 or 80.
Clearly trains are the only way to really get around the drag issue and still be able to move efficiently as only the engine has to move the air out of the way.
Now for the rest of your plug-in skepticism:
I used the effective well to wheels efficiency in order to truly compare apples to apples since other fuel sources are very hard to compare with.
Coal is nasty, dirty burning stuff but it can be scrubbed from stationary stacks fairly cleanly. It isn't renewable but isn't being used for much else besides keeping the economy of W. VA going and in stress due to mining accidents. Not really a sutainable source but will work for a long time and no war is required for the US. Efficiency is kind of irrevelant since it isn't good for much else besides electric power generation.
Nukes are clean 'burning' and quite efficient through turbines. It isn't renewable either as there isn't an unlimited supply of fissionable material on the planet - ok may fussion has potential but no one has figured out how to use it.
Natural gas, while non-renewable is currently under-utilized and offers perhaps the most efficiency when used in co-generation powerplants. They can get into the 80% efficiency region. Cogeneration plants burn the gas in an efficient gas turbine to get a lot of energy out, then use the exhaust from the gas turbine to drive a steam turbine to get additional energy out from the waste heat. This can be done in large plants but is not feasible with small, mobile engines such as are in cars.
Hydro-electric is really quite benign as long as one is ok with giving up a little bit (ok, a lot) of mountain valley real estate. It's great stuff, reliable, on-demand, zero pollution, renewable (as long as that huge fusion reaction in the sky keeps burning). It also can be used to store energy from inconsistant energy sources such as wind and solar - although clearly at a loss of efficiency.
Solar and wind are clearly long term winners since they are 100% renewable as long as our favorite fusion reaction remains hot. They have storage problems that pose challenges but they are both showing great progress as far as increasing efficiency.
Bio-mass fuels show great promise and could just as easily, in fact, perhaps more easily be used in efficient stationary generation facilities, then transported as electricity to the points of use than being converted to liquid and pumped or trucked.
The beauty of electric power generation is that one has a huge choice of sources to chose from, each one with different merits depending upon where one is.
You mention the losses during electricity distribution: This is a good point, however, when electricity is transformed up to extremely high voltages, as are used in high-tension transmission lines, the losses are quite small, around 10% across the grid, much less for short hauls. While substation transformers may get warm, compared to the amount of energy that passes through, the energy loss is very small.
You missed the losses in battery charging and discharging. These are not insignificant. Battery discharging and charging are about 90% efficient (which, of course, is only 81% round trip efficient)
The effect on the power grid of night charging will be non-existant for a long time since most power plants waste energy at night. They have to run all the time since it takes so long for them to start up. Plug-in vehicles offer a great opportunity for the power companies to make money off of the wasted night-time energy as well as make money off of their grid at night. Of course, I can assure you, the miserly consumption of my EV1 was such that you can't tell from looking at my electric bill that I even had the car for 3 years. It cost me about $1 to fill my car at home and each fillup would take me nominally 100 miles. I never went to the off-peak electric rates since I knew EV1 would be a short-lived pleasure and wouldn't warrant the cost of a new electric meter or a timer on my charger.
gas cogen 80%
electric motor 80%
I'll add that I know people in California with solar cells installed on their houses that drive EV's as their primary vehicles and have essentially zero electric bills. Their power meters run backward so they sell electricity when the sun is shining and buy electricity when it isn't but their average is nearly zero. This will be tougher in northern latitudes but it really does provide locally generated (nix a lot of those transmission losses) fully renewable power.
Now that I've done the math for plug-ins, its your turn to reciprocate for diesels: Remember you're starting out with 25% (generous assumption) and it only gets worse as you deduct:
- refining losses
- transportation losses
I'll let you skip all the war costs and hidden health issue costs although they are pretty nasty if you start digging in to them.
I'll help your numbers out a bit: adding a strong non-plug-in hybrid brings your 25% starting value up to maybe 35%. A wimpy hybrid as we have today may bring you to 30%.
02-13-2006, 09:42 PM #104
Hybrid vs. Diesel Debate
If the math is boggling, here's another thing I took off of a different email list that really hits the point:
"Plugging in your hybrid is like buying gas for 60 cents a gallon"
02-14-2006, 11:17 PM #105
Hybrid vs. Diesel Debate
Hybrid vs. Diesel
Well, for all you people out there toting the advantages of diesel or talking about a diesel hybrid or any engine that burns a diesel derivative need to wake up and smell the exhaust. While the fuel economy is good, the emissions are not. Even the biodiesel option results in some nasty fumes and/or by-products because of the blending and/or manufacturing process.
A hybrid diesel will still have to run the diesel since diesel engines don't like to be turned off and on all the time, resulting in emissions. Most railroad locomotives are (mentioned earlier in the thread) are not really hybrids but electro-motive engines. A large 2 or 4 stroke engine powers a generator that produces electricity for electric motors on the axles, however, most do not have batteries to store the electricity. A few of the newest ones (known as Green Goats) have been built as true hybrids electro-motive engines. These locos have a huge bank of batteries that run the motors on the axles and a small diesel (by railroad standards) that simply runs a generator that keeps the battery bank topped off. They also allow the motors to regenerate to charge the system. The result is a diesel that doesn't have to run for hours at a time. This would be the D-Hybrid everyone is dreaming about, however we don't have small enough, light enough or powerful enough batteries to allow the performance to overcome the weight issues of the batteries and traction motors without requiring the diesel to run. (However, the D-Hybrid is closer for larger vehicles like Buses (GM already built them), trucks, and SUVs. (Yes, a D-hybrid electro-motive system would be more efficient than any of the proposed systems in this thread, but THEY WILL ONLY FIT IN SUVs AND TRUCKS!)
Whether you Americans want to face it or not, your air quality is much better than Europe's. (LA's air would top the quality list with any of Europe's major cities.) There are two major reasons: the catalytic converter requirements in the US that are not possible with diesel, and Europe's excessive use of diesels!
A new cleaner burning diesel from VW or any carmaker is as likely as a zero emission Edison Electric coal plant!
Also, the people who live in California, Washington and on the east coast need to understand that any proposed car or truck has to function anywhere in the country. The people on the Plains who have to drive 50 miles to find a McDonald's don't want a car that needs a block heater and 15 minutes for the glowplugs to warm up before it will start from October to April. And yes, VW and others claim that's not true anymore, however my family in ND will tell you otherwise.
For now, in the immediate future, we should consider ethanol-hybrids. Bush has put this on the front page. GM and Ford have surprised many with the fact they have been selling clean burning cars for years without telling anyone. E85 vehicles outnumber hybrids 3 to 1. All we have to do is get them fuel. Imagine, almost 5 million trucks, large cars and SUVs could cut their emissions in half by the end of the year without a single penny in cost to their owners!
Oh, yeah, Hybrid vs. Diesel? Hybrid (with E85, not diesel.)
02-15-2006, 02:37 AM #106
Hybrid vs. Diesel Debate
I tend to disagree on the emissions issue. First, I'd like to know upon what the "LA's air would top the quality list with any of Europe's major cities" assertion is based. That's not my understanding (Europe has more strict ambient air quality standards). Furthermore, PM emissions from all those diesel cars in Europe only make up 2.5%-3% of the total ambient PM (http://www.dieselforecast.com/Articl...?articleID=235).
Second, saying that diesels have higher emissions is misleading at best. There are myriads of emissions from combustion processes. Diesels do tend to have higher NOx and PM emissions, but lower emissions of NMHCs and CO, catalytic converter or not. And certainly no one can argue that diesels have lower CO2 emissions. On top of that, gasoline is an extremely volatile substance (7-10 psi compared to 0.007 psi for diesel - biodiesel even lower based on a higher flash point; ethanol won't help this disparity). Does anyone realize how much VOCs are generated from gasoline distribution and refueling? I would argue that NMHCs (VOCs) are a much more important factor in air pollution than NOx (e.g., weekend ozone effect). Plus gasoline vapors decompose into such nasty components as formaldehyde and organic PM.
No question that diesel emissions need to be reduced (which they are with PM filters), but to imply that they're somehow much worse for air quality than gasoline engines is simply missing the total picture.
02-15-2006, 04:17 AM #107
Hybrid vs. Diesel Debate
This afternoon walking across my Publix supermarket parking lot I found a noisy, new Ford F-350 diesel parked and idling next to my Hybrid.
I had to hold my breath within 30 feet of it, right up to unlocking my door.
As I climbed inside I noticed my eyes beginning to sting.
Yes, the stigma perpetuates.
I'm sure the driver believes his diesel is a wonderful vehile. Other folks around it likely have a different view.
02-15-2006, 05:16 AM #108
Hybrid vs. Diesel Debate
First of all, I can say that I love diesels. I have owned five diesel autos, the last being a diesel VW Jetta 2004. Now, I own a 2005 Prius and am waiting on my 2006 to arrive. The reason that I have abandoned my diesels are as follows: Cost, at least 20 cents more per gallon of fuel. Maintenance, diesels require MUCH more care to keep them running. Trade in value for diesels is always much lower unless trading for another diesel. In order to get decent mileage in a diesel, you must have a standard transmission. All automatics do very poor with mileage. I just got plain tired of shifting all the time, especially in traffic. My automatic Prius averages 50 miles per gallon driving normally and thats with a/c on most of the time here in Florida. Diesel fuel is very, very dirty both in refueling and all the crap that goes into the air from the tailpipe. I think the diesel engine will probably not survive in our future auto industry in the United States.
02-15-2006, 06:36 AM #109
Hybrid vs. Diesel Debate
Trade-in value for diesels is very high in Canada. Just yesterday I ran some numbers through the Canadian Black Book site for a friend with an '03 Camry (LE, 4-cyl) he's thinking of trading. He paid $26k for it (all figures Canadian $) and the blackbook site came up with $13.5k-$14.5k The dealer had offered him $12k-$13k. I ran the numbers on a base Jetta GLS TDI for fun and it spit out $17k-$18.5k for the Jetta.
I had an early Jetta TDI on the A4 platform (the previous generation model) and indeed that car had many maintenance issues. Our '04 Jetta and '05 Passat have required very little maintenance. Timing belt replacement intervals have gone up from 90k km to 160k km (100,000 miles) since the 2003 m.y. and the new high life belt can be retrofitted to the previous model. Oil changes are every 10,000 miles. We have had no issues outside routine maintenance except for suspension damage on the Jetta after hitting a broken chunk of metal broken off a snow plow.
As for the pollution issue it's correct to state that there are many issues involved. For example, diesels tend to produce more particulate matter but the particle size is larger than for gas engines and thus the particulates are less likely to be inhaled, are heavier, don't disperse as easily and tend to deposit on the ground (notice the downward curving exhaust pipes on a modern diesel, it's for a good reason!).
Also, if you consider diesels from the wellhead to the road, they come out even better.
(ps for those comparing a Ford truck to a VW diesel: the truck does not have to adhere to the same emission standards as the car...)
02-15-2006, 09:49 PM #110
Hybrid vs. Diesel Debate
Why don't you believe that "we don't have small enough, light enough or powerful enough batteries to allow the performance to overcome the weight issues of the batteries and traction motors without requiring the diesel to run"? The fastest street legal dragsters are electric powered(http://www.nedra.com/). Torque is no problem for electric motors and battery technology has shown huge capacity increases in the past decade, mainly driven by the laptop computer and cellphone industries.
Many here probably tire of hearing my support of plug-in capability added to hybrids, however, if a large amount of one's driving were powered from the electric grid, the amount of time the internal combustion engine runs will diminish a lot. This makes a diesel hybrid a lot more attractive since the diesel would only fire up occassionally on longer trips or when grid charging wasn't convenient. When the diesel does fire up, it would fire up for a long time and run at a fairly constant speed/load. Thus:
- diesel emissions would be reduced since they are worst while a diesel is running hard. The electric would handle those tough times
- glow plug time wouldn't matter since the vehicle would be running on electric (whether or not it's really an issue).
- your relatives in ND would charge every time they plug into an engine block heater plug commonly found in ND parking lots.
- while somewhat less clean than gasoline engines, the fact that they would run less often will offset the average emissions
- diesels are much more flexible as to the fuel they burn (bio-diesel, dino-diesel, gasoline blends, ethanol blends, etc)