gagrice! Thank's for noticing me! The 900 mile,10 gal trip was based on 90mpg. Which I believe honda could achieve by next model year. I would expect the car to perform equal to a 2.4cyl accord. The electric motors are supposed to be quick of the mark. If somebody wants to buy a race car then that's what they should buy!The point of the post is, why fight over which is better. Why not combined the best of both. We should be cautious about over observing the tree, whilst the forest burns behind us. I've been watching some of the websites and news articles and I see little or no mention of diesel electric. Maybe Edmunds should write a lead article on the issue. They should have access to people and information, that would take me a year to put together. Thanks! Ps. run it through your head, see what pop's out!
There are others on here that know more about the intricacies of Hybrid vehicles. It seems that it may be more difficult to start and stop a diesel engine than a gasoline engine. A continuous running diesel with electric drive as is used in buses and heavy equipment may be the answer. we are just at the edge of discovery on all these modes of transportation. It is fun and exciting to see what they come up with next.
A diesel hybrid, slated for 2006 ... - snip - GM Daewoo Auto & Technology Co., South Korea's third-largest automaker, said Wednesday it will reveal a new sports utility hybrid vehicle at the Paris Motor Show, slated to open on Saturday. The diesel-powered S3X concept car is a seven-passenger model with a louvered glass roof that offers maximum interior room in a compact package, the automaker said. http://motortrend.com/features/news/112_news003/
It's been discussed several times before. The key thing if that diesel stands less to gain to the addition of extra $ in hardware is not as attractive.
As for car mags, c&d is my least favorite. They have a political stance i don't agree with, it bleeds into the articles and is clear in the editorials.
"As for car mags, c&d is my least favorite. They have a political stance.."
They trashed the Echo more. Did you see the points that they gave Echo? Anyway, the result speaks for itself.
"The key thing if(is) that diesel stands less to gain to the addition of extra $ in hardware is not as attractive."
There is a chance that we might see diesel-electric hybrid soon. The costs are going to be high since both diesel and hybrid technologies add extra cost to the vehicle. Diesel might need to couple with hybrid option to survive!
Diesel has a very tough road ahead through time. Time is not in favor of diesel. The most difficult problem diesel must face is it's emission, especially NOx. It is critical for diesel to achieve ultra low NOx emission or diesel will not survive in the passenger car industry.
In Europe, modern common rail, direct injection, high compression, turbo charged diesel engines will need Low Sulfer Diesel fuel to meet the soon-to-be Euro IV standard. In order for those modern diesels to reach US, they must cut their emission by more than two times than Euro IV or Federal government would not allow the sale of any diesel cars! There are technologies in the work from Toyota, Nissan, Honda and the big 3 US companies to meet those stringent US emission requirements. Toyota is in the lead now. Toyota can barely meet Tier 2 Bin 5 with their D-CAT technology when the filter is fresh when used with Ultra Low Sulfer Diesel(<15ppm) fuel.
D-CAT must be tested for 50,000 miles and must maintain the minimum emission requirement in order to be allowed to be sold in US. At 100,000 miles, it must meet another requirement(allows more NOx) and so on. This diesel emission reduction technology costs as much as a full hybrid option and reduces fuel economy by a few percent!
If the particle filter and catalytic for diesel can not meet US emission by 2007(just 3 years left), then the only way I see diesel to reduce further NOx emission is by going diesel-electric hybrid! Hybrid option for diesel would enable the ICE to be smaller, which in turn, burns less fuel, which in turn, reduce emission.
BTW, Euro V is suppose to take effect by 2008 which will require diesel cars to reduce it's NOx emission by 1/5th of the Euro IV requirement!
There is a chance that we might see diesel-electric hybrid soon. The costs are going to be high since both diesel and hybrid technologies add extra cost to the vehicle. Diesel might need to couple with hybrid option to survive!
Diesel engines cost more for the same size, but with their greater torque and efficiency you can use a smaller diesel than comparable gas engine.
I think it would be reasonable for a Civic Hybrid sized vehicle to use a 2-cyl. diesel with turbo combined with a drive system like Toyota's HSD to keep it in at peak torque when accelerating. That would boost mileage, which would reduce emissions.
"I especially liked the part about emissions system costing as much as the hybrid drivetrain. Can you please reference that specific fact? "
Sure. The following is some of what that recent report said.
"....Recently, hybrid costs have come down and the few hybrid makes available are selling well. Diesels have made great strides in reducing particulate and nitrogen oxide emissions, and are likely though not certain to meet future standards,” concluded the authors of the report."
They must be referring to Prius and HCH which are selling well.
"The study forecast that diesel engines should be able to meet Tier 2 emission standards. The added cost of emission control systems, however, will make the cost penalty in diesels comparable to that in hybrid vehicles...."
That's just the emission control systems alone. Why not drop the whole emission filtering system and go with diesel-electric hybrid? This way, you gain more efficiency and lower the emission, killing two birds with one stone.
"The major obstacle preventing diesels from wider entry into the US market are the stringent NOx emission limits in the federal Tier 2 and, even more so, the California LEV II emission standards. For new passenger cars and light light-duty trucks (LDT), Tier 2 standards phase-in beginning in 2004, with full implementation by 2007."
Diesel's situation is much worse than anyone realized! It seems to me like Diesel is an endangered fuel/drivetrain which is in need of hybrid to the rescue. Diesel-electric price will be high but will it worth double the extra cost?
"Diesel engines cost more for the same size, but with their greater torque and efficiency you can use a smaller diesel than comparable gas engine."
Doesn't Diesel has lower rev RPM, therefore, lower horsepower? The torque peak is high but has the "sling shot effect" because torque curve(blue) is like a mountain.
In comparison, Atkinson cycle gas engine used in Prius has super flat torque curve(below) with consistence horsepower incline.
I’ve seen you mention “super flat torque curve” of the Prius 1.5/I-4 more than three times. The fact is, it isn’t a big deal to have a flat torque curve when a 1.5-liter engine has to deliver a maximum of only 82 lb.-ft.
"it isn’t a big deal to have a flat torque curve when a 1.5-liter engine has to deliver a maximum of only 82 lb.-ft."
It sure makes the hybrid ECU's job much easier to control transition between ICE and electric. It is also important to be able to split power at a consistence manner. You don't want situations where HSD suddenly requires more power and ICE can't provide enough because the RPM that currently at has low torque.
"The major obstacle preventing diesels from wider entry into the US market are the stringent NOx emission limits in the federal Tier 2 and, even more so, the California LEV II emission standards."
It would seem to me that there is some outside influence in some of these decisions. For example how closely do these CARB types work with the Oil and Auto industry. I personally know many environmental scientists in Alaska that are on BP payroll. So the studies are by the people who have the most to gain by blocking higher efficiency in our cars. Honda proved you could have a very efficient 50 mpg good performing car in the 1980s with the Civic HF. I think they got shot down by the politicians. They allow us to have what they think they can get away with. They dribble the technology out in little chunks. The hybrid is the bit we get this decade.
"Power split is in percentages. How is making less torque beneficial?"
I didn't say less torque is beneficial. You want consistence torque because horsepower delivery is consistence at any RPM range. It doesn't matter who control it, either you(manual tranny) or the computer(HSD).
In HSD, the ICE doesn't need to make a lot of torque because high torque is the electric motor's specialty.
"It would seem to me that there is some outside influence in some of these decisions."
Are you saying it is wrong to have the same emission standard for Gasoline and Diesel powered vehicle? Why should diesel be allowed to pollute more than gas cars after it is proven that NOx causes cancer?
As much blame can be put on the people who won’t shy away from putting down a 62 HP hatchback and would have virtually no convenience features. And we won’t even talk about structural issues.
Cars like Honda Fit/Jazz may help revive high mileage cars. The 1.3-liter i-DSI engine used in Civic Hybrid was borrowed from Fit/Jazz and is one of the best gasoline engine choices out there to extract the most miles for a gallon. But, 86 HP (5700 rpm) and 88 lb.-ft (2800 rpm) isn’t going to attract many buyers. That is a reality too!
Even in the Japanese market, Honda has dumped the 1.3 i-DSI unit from Jazz in favor of 110 HP 1.5-liter VTEC unit, and in the process compromising a bit in terms of fuel economy (the i-DSI unit was rated at 23 km/l the 1.5 brings it down to 19.2 km/l). However, in the European market, Honda is getting ready to release a 1.2-liter version (the 1.3-liter engine is classified as 1.4 in Euro market).
"Why should diesel be allowed to pollute more than gas cars after it is proven that NOx causes cancer?"
If NoX is as bad as you say. They need to outlaw all the Oil furnaces in the USA. They spew raw PM into the air all winter long. Far exceeding the little a modern diesel puts out. Also I have always advocated ULSD. Why we are so far behind can only be political.
You want consistence torque because horsepower delivery is consistence at any RPM range.
Flat torque curve is desirable, but not the end of it. Here is the torque curve of the 1.3-liter i-DSI engine used in (European) Honda Jazz and Civic Hybrid
Between 1000 and 6000 rpm, the engine makes 74-88 lb.-ft. That’s very flat, isn’t it (at least 84% of the peak torque is maintained through out)? I just don’t see how your argument bodes with the idea that getting 75 lb.-ft across the rev range would be better.
In case of diesels, their strong suit is typically 1500 thru 3000 rpm. They have steep slopes at either side. But this also makes them good candidates for load pulling applications and yield very good BSFC in the process (hence their use in locomotives over gasoline engine).
In HSD, the ICE doesn't need to make a lot of torque because high torque is the electric motor's specialty.
I would say we already have different standards. How many times have you had to pass a truck on the highway. Because you couldn't stand the exhaust fumes that were getting in your closed up passenger compartment! gagrice you hit one of the nails right on the head.
Yup. That sums it up. All I presented were a Diesel and Atkinson Gas engine torque curve and said flat is better. The rest of mumbo jumbos are coming from you.
"So, is RX400h going to use 1.5/I-4? Why not?"
No, it is going to use 3.3/V-6. It is a bigger and heavier performance lexury SUV. RX400h doesn't cut corners on it's electric powertrain either. FWD RX400h's main electric motor(120kW) is going to be 10 times more powerful than Accord Hybrid's(12kW). 4WD-i RX400h will have another 50kW motor in the rear. It will also be rated as SULEV, one of the most stringent emission standard.
"I would say we already have different standards. How many times have you had to pass a truck on the highway. Because you couldn't stand the exhaust fumes that were getting in your closed up passenger compartment!"
There are seperate emission requirements for light truck and heavy duty trucks. You know what's ironic? With ultra low sulfer diesel fuel, it is possible make a diesel-electric hybrid car that is lower in emission than Honda Accord Hybrid(yes, even NOx)! That's why I am all over at HAH board. But the cost is going to be very high.
It's all relative to the size of the vehicle and performance desires. Electric motor does excellent job providing high torque. ICE needs to do excellent job extracting as much energy from gasoline or diesel because that's where all the energy is coming from. Simple concept.
High torque at low revs produces high acceleration. Anyone who's driven a diesel or a V-8 with an "RV cam" can vouch for that. You can feel it. The problem is no-one can explain it looking at torque curves.
I will explain it. The problem is the way we draw the curves. The RPM is a linear scale. It needs to be a logarithmic scale. Let me explain why:
When you accelerate through a gear, you cover a range of ratios, not a range of RPMs. For example, if at each shift you dropped to 80% of the revs you were in (shifting 1-to-2, 2-3, 3-4...) then the width of the RPM range in each gear would be fixed on a logarithmic scale.
But on a linear scale, it isn't fixed. An increase in 1000 RPM changes the vehicle speed a variable amount depending on what gear you are in. Going from 1000 revs to 2000 revs doubles speed (big acceleration), but 6000 revs to 7000 revs increases speed only 16%. The range looks the same on a torque curve (same width) but is completely different in terms of performance.
If we drew the torque/HP charts with a logarithmic scale, then you would see ~2000 RPM in the center, and maybe 10,000 RPM at the right side. Plot a diesel's torque, and its a big, wide hump. Plot the torque of Honda's S2000 sports car (with 240 HP @ 7800 RPM, and peak torque of 162 pounds at 6500 RPM) and the somewhat narrow peak on a linear scale becomes a slim notch sticking up near the right side of the chart of the log chart.
Here's an example to illustrate: Take a Passat TDI with >240 pounds torque from ~1800 to 3600 revs. That's a 1:2 ratio. It can apply that torque from (a simple example) 30 to 60 MPH without shifting or dropping out of the "power band". But if the Honda's torque lives in the 6000 - 8000 range, that's only a 1:1.33 ratio, meaning it can only go from 30 to 40 MPH in the power-band, and you have to shift already. (then 40 to 53 and shift again, then 53 to 70 and you shift again.... you get the idea)
Hence the Honda comes with a 6-speed tranny. It HAS to! The ratio from one gear to the other has to be slim, so it needs more ratios. And most reviews talk about having to "stir the shifter continuously" to get the performance out of it. If it had a 4-speed it would be a total dog in a drag-race. The ratios would be too wide.
A lowly VW Beetle Cabrio comes with a 6-speed Tiptronic automatic, but the high-end Passat TDI only has a 5-speed Tiptronic automatic. Why? The Passat Diesel doesn't need more gears. They would be a waste. And the additional time shifting would make the sprint from 0-60 MPH take LONGER, not less time.
Sorry for the long post, but torque & HP comparisons would be so much easier if we just drew the charts in a meaningful fashion, rather than in a linear style that makes high-rev power look like a lot more than it is ... a short blip before you have to shift to the next gear!
So Dennis, I agree with you that a flat torque curve is desirable, but only as apposed to one that peaks at high revs.
But having a flat curve with LOTS of torque is more desirable.
If you cut the Passat's diesel engine in 1/2 (a 1-liter, 2-cyl. engine) it would still have 50% MORE torque than the Prius' 1.5L 4-cyl. gas engine. It would be faster for sure if it replaced the Toyota gas engine, and there's a good chance it would consume less fuel (but I'll never know unless I hack apart a Prius and a Passat engine, and they're both too expensive to start chopping up
Brian
PS: NOx emissions are dealt with by catalytic converters, which my VW diesel has. That's part of the reason that it is SMOG legal in Calif.
Electric motor and gasoline (or diesel) motor have to combine to get you performance. Engineers can opt to lean one way or the other depending on what needs to be achieved. Either choice will come with a compromise, and that is the bottom line.
In your attempt to explain the benefits of high torque, and significance of flat torque curve, you’ve completely ignored the appreciation of power. And no, I’m not necessarily talking about “peak power”, but power, and it happens everywhere along the engine speed range.
And since you brought up S2000, you must realize that even with more torque, the Passat TDI won’t be able to keep up simply because it won’t have the horses. As far as choice of “speeds” in a transmission is concerned, you also need to know that it is about trying to maximize power being delivered to the wheels. This is why luxury sedans are coming out with 6 or 7 speed automatic transmissions. And those semi engines are coupled to what, 18-speed gear boxes? Think, why?
"If you cut the Passat's diesel engine in 1/2 (a 1-liter, 2-cyl. engine) it would still have 50% MORE torque than the Prius' 1.5L 4-cyl. gas engine.
Yes, but makes less horsepower. For the Prius powered by HSD, high-torque ICE is not required. In fact, only 27% of ICE torque is split to the wheel. HSD can always generate electricity and output 295lbs-ft torque from 50kW electric motor. The power split is controlled by the MG1 acting as a generator.
"Electric motor and gasoline (or diesel) motor have to combine to get you performance."
I agree. Electric side has more potential to improve. For example, energy storage devices such as better batteries and ultracapacitors.
"Engineers can opt to lean one way or the other depending on what needs to be achieved."
I agree with you to an extend. Would you agree that for an ICE-Electric hybrid, 50:50(ICE:Electric) be an ideal? If there is a need for more power, sure, raise power to both. As in HAH's case, ICE is 15 times more powerful than it's electric motor. That's out of balance.
"And those semi engines are coupled to what, 18-speed gear boxes? Think, why?"
Well, semi engine probably have limited range in RPM. In order to change thrust at the wheels, gearing needs to spread apart extremely wide. The lowest gear would create probably 15x more thrust than engine's max torque can produce.
Typical semi engines used be setup for max torque starting at 1700 RPM with a red-line of only 2100 RPMs. A narrow power-band requiring many ratios to use it over all speeds.
Would you agree that for an ICE-Electric hybrid, 50:50(ICE:Electric) be an ideal?
No. There can be no ideal. No technology is perfect, and you’ve to deal with compromises. It is all about getting the job done with simplicity and minimum overhead.
Typical semi engines used be setup for max torque starting at 1700 RPM with a red-line of only 2100 RPMs. A narrow power-band requiring many ratios to use it over all speeds.
There we go. While a Freightliner engine can have a diesel engine delivering 1650 lb.-ft at 1500 rpm or so, the need to accelerate while being able to multiply the torque enough to pull the load is limited by meager 500 HP. As a result, the shifts have to be frequent, hence the need for 13-18 speed gear boxes. The bottom line is… need to keep the engine as close to its peak power lever as possible. Now, you should know why S2000 has six speed transmissions. The drive train of the car is optimized for performance, and maximizing horsepower at the wheels, not your typical diesel powered car. The car could as well have used a 3 or 4 speed transmission.
i'm wrong for saying a rig needs 18 gears because its hauling 30 tons? sorry, but its true. It may not be the complete story, but its a big part of it. If you put that engine in a 2-ton vehicle, you wouldn't need anywhere near that many gears. Why? Because you could easily get it going in very high gear. The limited HP has very little to do with it. Its the weight its pulling and the inherent low redline of a diesel.
I don't know, I thought we were almost saying the same thing, but since you said my first post was wrong, I have to think we're on different pages here.
'11 GMC Sierra 1500; '98 Alfa 156 2.0TS; '08 Maser QP; '67 Coronet R/T; '13 Fiat 500c; '20 S90 T6; '22 MB Sprinter 2500 4x4 diesel; '97 Suzuki R Wagon; '96 Opel Astra; '11 Mini Cooper S
You weren't wrong, you were incomplete in that you missed a huge part of the equation, and that is lack of horsepower. And now, with your statement that lack HP isn't a part of the issue, you've made your case worse.
exactly like you said, you need to start in ultralow gear to get that mass moving.
So ... let's approach this a little bit different. Are you trying to tell me that 1000 hp in a freightliner would eliminate the need for all those gears?
Oh, and, just to clarify, I did not say HP is not part of the issue. My exact words were "it has very little to do with it." I, of course, understand that, with zero HP, you aren't going anywhere, so I understand that you still need HP. that's just those pesky physics for ya.
'11 GMC Sierra 1500; '98 Alfa 156 2.0TS; '08 Maser QP; '67 Coronet R/T; '13 Fiat 500c; '20 S90 T6; '22 MB Sprinter 2500 4x4 diesel; '97 Suzuki R Wagon; '96 Opel Astra; '11 Mini Cooper S
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".
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.
'11 GMC Sierra 1500; '98 Alfa 156 2.0TS; '08 Maser QP; '67 Coronet R/T; '13 Fiat 500c; '20 S90 T6; '22 MB Sprinter 2500 4x4 diesel; '97 Suzuki R Wagon; '96 Opel Astra; '11 Mini Cooper S
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.
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.
'11 GMC Sierra 1500; '98 Alfa 156 2.0TS; '08 Maser QP; '67 Coronet R/T; '13 Fiat 500c; '20 S90 T6; '22 MB Sprinter 2500 4x4 diesel; '97 Suzuki R Wagon; '96 Opel Astra; '11 Mini Cooper S
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).
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.
'11 GMC Sierra 1500; '98 Alfa 156 2.0TS; '08 Maser QP; '67 Coronet R/T; '13 Fiat 500c; '20 S90 T6; '22 MB Sprinter 2500 4x4 diesel; '97 Suzuki R Wagon; '96 Opel Astra; '11 Mini Cooper S
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
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.
'11 GMC Sierra 1500; '98 Alfa 156 2.0TS; '08 Maser QP; '67 Coronet R/T; '13 Fiat 500c; '20 S90 T6; '22 MB Sprinter 2500 4x4 diesel; '97 Suzuki R Wagon; '96 Opel Astra; '11 Mini Cooper S
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?
Comments
As for car mags, c&d is my least favorite. They have a political stance i don't agree with, it bleeds into the articles and is clear in the editorials.
dave
I think 92mpg is Imp. MPG. In US term, it is 76.6 MPG. Impressive but Prius was recorded at 85.7 MPG over 967 miles run. Here is the pic.
Straight from www.honda.co.uk, Honda Accord Saloon's Combined (mpg) is 52.3(US 43.5 MPG).
Dennis
They trashed the Echo more. Did you see the points that they gave Echo? Anyway, the result speaks for itself.
"The key thing if(is) that diesel stands less to gain to the addition of extra $ in hardware is not as attractive."
There is a chance that we might see diesel-electric hybrid soon. The costs are going to be high since both diesel and hybrid technologies add extra cost to the vehicle. Diesel might need to couple with hybrid option to survive!
Diesel has a very tough road ahead through time. Time is not in favor of diesel. The most difficult problem diesel must face is it's emission, especially NOx. It is critical for diesel to achieve ultra low NOx emission or diesel will not survive in the passenger car industry.
In Europe, modern common rail, direct injection, high compression, turbo charged diesel engines will need Low Sulfer Diesel fuel to meet the soon-to-be Euro IV standard. In order for those modern diesels to reach US, they must cut their emission by more than two times than Euro IV or Federal government would not allow the sale of any diesel cars! There are technologies in the work from Toyota, Nissan, Honda and the big 3 US companies to meet those stringent US emission requirements. Toyota is in the lead now. Toyota can barely meet Tier 2 Bin 5 with their D-CAT technology when the filter is fresh when used with Ultra Low Sulfer Diesel(<15ppm) fuel.
D-CAT must be tested for 50,000 miles and must maintain the minimum emission requirement in order to be allowed to be sold in US. At 100,000 miles, it must meet another requirement(allows more NOx) and so on. This diesel emission reduction technology costs as much as a full hybrid option and reduces fuel economy by a few percent!
If the particle filter and catalytic for diesel can not meet US emission by 2007(just 3 years left), then the only way I see diesel to reduce further NOx emission is by going diesel-electric hybrid! Hybrid option for diesel would enable the ICE to be smaller, which in turn, burns less fuel, which in turn, reduce emission.
BTW, Euro V is suppose to take effect by 2008 which will require diesel cars to reduce it's NOx emission by 1/5th of the Euro IV requirement!
Dennis
Diesel engines cost more for the same size, but with their greater torque and efficiency you can use a smaller diesel than comparable gas engine.
I think it would be reasonable for a Civic Hybrid sized vehicle to use a 2-cyl. diesel with turbo combined with a drive system like Toyota's HSD to keep it in at peak torque when accelerating.
That would boost mileage, which would reduce emissions.
Brian
I especially liked the part about emissions system costing as much as the hybrid drivetrain. Can you please reference that specific fact?
dave
Sure. The following is some of what that recent report said.
"....Recently, hybrid costs have come down and the few hybrid makes available are selling well. Diesels have made great strides in reducing particulate and nitrogen oxide emissions, and are likely though not certain to meet future standards,” concluded the authors of the report."
They must be referring to Prius and HCH which are selling well.
"The study forecast that diesel engines should be able to meet Tier 2 emission standards. The added cost of emission control systems, however, will make the cost penalty in diesels comparable to that in hybrid vehicles...."
That's just the emission control systems alone. Why not drop the whole emission filtering system and go with diesel-electric hybrid? This way, you gain more efficiency and lower the emission, killing two birds with one stone.
"The major obstacle preventing diesels from wider entry into the US market are the stringent NOx emission limits in the federal Tier 2 and, even more so, the California LEV II emission standards. For new passenger cars and light light-duty trucks (LDT), Tier 2 standards phase-in beginning in 2004, with full implementation by 2007."
Diesel's situation is much worse than anyone realized! It seems to me like Diesel is an endangered fuel/drivetrain which is in need of hybrid to the rescue. Diesel-electric price will be high but will it worth double the extra cost?
Web link to the news:
http://www.dieselnet.com/news/0409doe.html
The US Department’s of Energy (DOE) Oak Ridge National Laboratory Report:
http://www-cta.ornl.gov/cta/Publications/pdf/ORNL_TM_2004_181_Hyb- - - - - ridDiesel.pdf
Doesn't Diesel has lower rev RPM, therefore, lower horsepower? The torque peak is high but has the "sling shot effect" because torque curve(blue) is like a mountain.
In comparison, Atkinson cycle gas engine used in Prius has super flat torque curve(below) with consistence horsepower incline.
Dennis
It sure makes the hybrid ECU's job much easier to control transition between ICE and electric. It is also important to be able to split power at a consistence manner. You don't want situations where HSD suddenly requires more power and ICE can't provide enough because the RPM that currently at has low torque.
Dennis
It would seem to me that there is some outside influence in some of these decisions. For example how closely do these CARB types work with the Oil and Auto industry. I personally know many environmental scientists in Alaska that are on BP payroll. So the studies are by the people who have the most to gain by blocking higher efficiency in our cars. Honda proved you could have a very efficient 50 mpg good performing car in the 1980s with the Civic HF. I think they got shot down by the politicians. They allow us to have what they think they can get away with. They dribble the technology out in little chunks. The hybrid is the bit we get this decade.
I didn't say less torque is beneficial. You want consistence torque because horsepower delivery is consistence at any RPM range. It doesn't matter who control it, either you(manual tranny) or the computer(HSD).
In HSD, the ICE doesn't need to make a lot of torque because high torque is the electric motor's specialty.
Dennis
Are you saying it is wrong to have the same emission standard for Gasoline and Diesel powered vehicle? Why should diesel be allowed to pollute more than gas cars after it is proven that NOx causes cancer?
Dennis
Cars like Honda Fit/Jazz may help revive high mileage cars. The 1.3-liter i-DSI engine used in Civic Hybrid was borrowed from Fit/Jazz and is one of the best gasoline engine choices out there to extract the most miles for a gallon. But, 86 HP (5700 rpm) and 88 lb.-ft (2800 rpm) isn’t going to attract many buyers. That is a reality too!
Even in the Japanese market, Honda has dumped the 1.3 i-DSI unit from Jazz in favor of 110 HP 1.5-liter VTEC unit, and in the process compromising a bit in terms of fuel economy (the i-DSI unit was rated at 23 km/l the 1.5 brings it down to 19.2 km/l). However, in the European market, Honda is getting ready to release a 1.2-liter version (the 1.3-liter engine is classified as 1.4 in Euro market).
If NoX is as bad as you say. They need to outlaw all the Oil furnaces in the USA. They spew raw PM into the air all winter long. Far exceeding the little a modern diesel puts out. Also I have always advocated ULSD. Why we are so far behind can only be political.
Flat torque curve is desirable, but not the end of it. Here is the torque curve of the 1.3-liter i-DSI engine used in (European) Honda Jazz and Civic Hybrid
Peak Power: 86 HP @ 5700 rpm
Peak Torque: 88 lb.-ft @ 2800 rpm
Between 1000 and 6000 rpm, the engine makes 74-88 lb.-ft. That’s very flat, isn’t it (at least 84% of the peak torque is maintained through out)? I just don’t see how your argument bodes with the idea that getting 75 lb.-ft across the rev range would be better.
In case of diesels, their strong suit is typically 1500 thru 3000 rpm. They have steep slopes at either side. But this also makes them good candidates for load pulling applications and yield very good BSFC in the process (hence their use in locomotives over gasoline engine).
In HSD, the ICE doesn't need to make a lot of torque because high torque is the electric motor's specialty.
So, is RX400h going to use 1.5/I-4? Why not?
Yup. That sums it up. All I presented were a Diesel and Atkinson Gas engine torque curve and said flat is better. The rest of mumbo jumbos are coming from you.
"So, is RX400h going to use 1.5/I-4? Why not?"
No, it is going to use 3.3/V-6. It is a bigger and heavier performance lexury SUV. RX400h doesn't cut corners on it's electric powertrain either. FWD RX400h's main electric motor(120kW) is going to be 10 times more powerful than Accord Hybrid's(12kW). 4WD-i RX400h will have another 50kW motor in the rear. It will also be rated as SULEV, one of the most stringent emission standard.
Dennis
There are seperate emission requirements for light truck and heavy duty trucks. You know what's ironic? With ultra low sulfer diesel fuel, it is possible make a diesel-electric hybrid car that is lower in emission than Honda Accord Hybrid(yes, even NOx)! That's why I am all over at HAH board. But the cost is going to be very high.
Dennis
Dennis
Anyone who's driven a diesel or a V-8 with an "RV cam" can vouch for that. You can feel it.
The problem is no-one can explain it looking at torque curves.
I will explain it. The problem is the way we draw the curves. The RPM is a linear scale. It needs to be a logarithmic scale. Let me explain why:
When you accelerate through a gear, you cover a range of ratios, not a range of RPMs. For example, if at each shift you dropped to 80% of the revs you were in (shifting 1-to-2, 2-3, 3-4...) then the width of the RPM range in each gear would be fixed on a logarithmic scale.
But on a linear scale, it isn't fixed. An increase in 1000 RPM changes the vehicle speed a variable amount depending on what gear you are in.
Going from 1000 revs to 2000 revs doubles speed (big acceleration), but 6000 revs to 7000 revs increases speed only 16%. The range looks the same on a torque curve (same width) but is completely different in terms of performance.
If we drew the torque/HP charts with a logarithmic scale, then you would see ~2000 RPM in the center, and maybe 10,000 RPM at the right side.
Plot a diesel's torque, and its a big, wide hump.
Plot the torque of Honda's S2000 sports car (with 240 HP @ 7800 RPM, and peak torque of 162 pounds at 6500 RPM) and the somewhat narrow peak on a linear scale becomes a slim notch sticking up near the right side of the chart of the log chart.
Here's an example to illustrate:
Take a Passat TDI with >240 pounds torque from ~1800 to 3600 revs. That's a 1:2 ratio. It can apply that torque from (a simple example) 30 to 60 MPH without shifting or dropping out of the "power band".
But if the Honda's torque lives in the 6000 - 8000 range, that's only a 1:1.33 ratio, meaning it can only go from 30 to 40 MPH in the power-band, and you have to shift already. (then 40 to 53 and shift again, then 53 to 70 and you shift again.... you get the idea)
Hence the Honda comes with a 6-speed tranny. It HAS to! The ratio from one gear to the other has to be slim, so it needs more ratios. And most reviews talk about having to "stir the shifter continuously" to get the performance out of it.
If it had a 4-speed it would be a total dog in a drag-race. The ratios would be too wide.
A lowly VW Beetle Cabrio comes with a 6-speed Tiptronic automatic, but the high-end Passat TDI only has a 5-speed Tiptronic automatic. Why? The Passat Diesel doesn't need more gears. They would be a waste. And the additional time shifting would make the sprint from 0-60 MPH take LONGER, not less time.
Sorry for the long post, but torque & HP comparisons would be so much easier if we just drew the charts in a meaningful fashion, rather than in a linear style that makes high-rev power look like a lot more than it is ... a short blip before you have to shift to the next gear!
Brian
But having a flat curve with LOTS of torque is more desirable.
If you cut the Passat's diesel engine in 1/2 (a 1-liter, 2-cyl. engine) it would still have 50% MORE torque than the Prius' 1.5L 4-cyl. gas engine. It would be faster for sure if it replaced the Toyota gas engine, and there's a good chance it would consume less fuel (but I'll never know unless I hack apart a Prius and a Passat engine, and they're both too expensive to start chopping up
Brian
PS: NOx emissions are dealt with by catalytic converters, which my VW diesel has. That's part of the reason that it is SMOG legal in Calif.
And since you brought up S2000, you must realize that even with more torque, the Passat TDI won’t be able to keep up simply because it won’t have the horses. As far as choice of “speeds” in a transmission is concerned, you also need to know that it is about trying to maximize power being delivered to the wheels. This is why luxury sedans are coming out with 6 or 7 speed automatic transmissions. And those semi engines are coupled to what, 18-speed gear boxes? Think, why?
'11 GMC Sierra 1500; '98 Alfa 156 2.0TS; '08 Maser QP; '67 Coronet R/T; '13 Fiat 500c; '20 S90 T6; '22 MB Sprinter 2500 4x4 diesel; '97 Suzuki R Wagon; '96 Opel Astra; '11 Mini Cooper S
Guess again!
Yes, but makes less horsepower. For the Prius powered by HSD, high-torque ICE is not required. In fact, only 27% of ICE torque is split to the wheel. HSD can always generate electricity and output 295lbs-ft torque from 50kW electric motor. The power split is controlled by the MG1 acting as a generator.
Looking at from another angle, Prius with 82 lbs-ft ICE outperforms it's cousin Allion with 147 lbs-ft torque! For more info:
usbseawolf2000 "Toyota Allion Vs. Prius" Jun 18, 2004 10:01pm
"It would be faster for sure if it replaced the Toyota gas engine, and there's a good chance it would consume less fuel.."
It could consume less fuel by going with 1.0 liter diesel engine but not faster as it makes less power. Emission would increase as well.
Dennis
I agree. Electric side has more potential to improve. For example, energy storage devices such as better batteries and ultracapacitors.
"Engineers can opt to lean one way or the other depending on what needs to be achieved."
I agree with you to an extend. Would you agree that for an ICE-Electric hybrid, 50:50(ICE:Electric) be an ideal? If there is a need for more power, sure, raise power to both. As in HAH's case, ICE is 15 times more powerful than it's electric motor. That's out of balance.
Dennis
Well, semi engine probably have limited range in RPM. In order to change thrust at the wheels, gearing needs to spread apart extremely wide. The lowest gear would create probably 15x more thrust than engine's max torque can produce.
Dennis
A narrow power-band requiring many ratios to use it over all speeds.
http://www.germancarfans.com/news.cfm/NewsID/2040108.001/mercedes- - /1.html
No. There can be no ideal. No technology is perfect, and you’ve to deal with compromises. It is all about getting the job done with simplicity and minimum overhead.
There we go. While a Freightliner engine can have a diesel engine delivering 1650 lb.-ft at 1500 rpm or so, the need to accelerate while being able to multiply the torque enough to pull the load is limited by meager 500 HP. As a result, the shifts have to be frequent, hence the need for 13-18 speed gear boxes. The bottom line is… need to keep the engine as close to its peak power lever as possible. Now, you should know why S2000 has six speed transmissions. The drive train of the car is optimized for performance, and maximizing horsepower at the wheels, not your typical diesel powered car. The car could as well have used a 3 or 4 speed transmission.
I don't know, I thought we were almost saying the same thing, but since you said my first post was wrong, I have to think we're on different pages here.
'11 GMC Sierra 1500; '98 Alfa 156 2.0TS; '08 Maser QP; '67 Coronet R/T; '13 Fiat 500c; '20 S90 T6; '22 MB Sprinter 2500 4x4 diesel; '97 Suzuki R Wagon; '96 Opel Astra; '11 Mini Cooper S
So, now explain to me, how 18-speeds help?
So ... let's approach this a little bit different. Are you trying to tell me that 1000 hp in a freightliner would eliminate the need for all those gears?
Oh, and, just to clarify, I did not say HP is not part of the issue. My exact words were "it has very little to do with it." I, of course, understand that, with zero HP, you aren't going anywhere, so I understand that you still need HP. that's just those pesky physics for ya.
'11 GMC Sierra 1500; '98 Alfa 156 2.0TS; '08 Maser QP; '67 Coronet R/T; '13 Fiat 500c; '20 S90 T6; '22 MB Sprinter 2500 4x4 diesel; '97 Suzuki R Wagon; '96 Opel Astra; '11 Mini Cooper S
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".
'11 GMC Sierra 1500; '98 Alfa 156 2.0TS; '08 Maser QP; '67 Coronet R/T; '13 Fiat 500c; '20 S90 T6; '22 MB Sprinter 2500 4x4 diesel; '97 Suzuki R Wagon; '96 Opel Astra; '11 Mini Cooper S
http://www.greencarcongress.com/2004/09/whatrsquos_the_.html
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.
'11 GMC Sierra 1500; '98 Alfa 156 2.0TS; '08 Maser QP; '67 Coronet R/T; '13 Fiat 500c; '20 S90 T6; '22 MB Sprinter 2500 4x4 diesel; '97 Suzuki R Wagon; '96 Opel Astra; '11 Mini Cooper S
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).
'11 GMC Sierra 1500; '98 Alfa 156 2.0TS; '08 Maser QP; '67 Coronet R/T; '13 Fiat 500c; '20 S90 T6; '22 MB Sprinter 2500 4x4 diesel; '97 Suzuki R Wagon; '96 Opel Astra; '11 Mini Cooper S
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
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.
'11 GMC Sierra 1500; '98 Alfa 156 2.0TS; '08 Maser QP; '67 Coronet R/T; '13 Fiat 500c; '20 S90 T6; '22 MB Sprinter 2500 4x4 diesel; '97 Suzuki R Wagon; '96 Opel Astra; '11 Mini Cooper S
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?