Au contraire! Regenerative braking motors can apply as much reverse torque as when the motors are used for propulsion. It is just a matter of how much current can be fed into the batteries. The maximum charging current is currently a bottleneck in the Prius, but this can easily be overcome by using either bigger batteries or large capacitors.
Since kinetic energy is proportional to velocity squared, regenerative charging current limitation equates to very light braking at high speeds and but allows for much heavier braking at low speeds. Thus, as stated previously, hybrids offer the most improvement in stop and go city driving.
DelJ
[quote]Drew - 3/26/2005 9:10 AM
(snip) ..regenerative braking (snip) does not slow down the vehicle that much at all.
The brakes still do need to be used as usual as the motor/generator does not provide <i>that</i> much resistance.[/QUOT
E]
Hybrids are still a science experiment waiting to be proven and in regards to economy, the extra cost is not made up in fuel savings until you drive 100K or more.
I'd much rather have an advanced diesel, expecially in something such as an ML.
I disagree. I am unaware of any significant issues having to do with hybrid driveability or reliability. Hybrids are on the road today from several manufacturers and seem to be working just fine.
The fuel savings are typically grossly underestimated as people tend to compare highway mileage when they should be comparing city mileage. Hybrids easily come out way ahead in crowded day to day commuting traffic.
It is the new advanced diesels that are unproven and full of hype. The last generation of diesels were a bunch of losers, and only the dieselheads were sorry to see them fall out of favor here in the USA.
DelJ
Quote:
Tim - 3/26/2005 10:24 AM
Hybrids are still a science experiment waiting to be proven and in regards to economy, the extra cost is not made up in fuel savings until you drive 100K or more.
I'd much rather have an advanced diesel, expecially in something such as an ML.
That would make the greenies go frothing at the mouth as they try to figure out whether to damn it or praise it [:D]
But seriously, I also wonder how long it is before the hybrid batteries need replacement (at one point, I read at a cost of $2-3K!) and whether the extra hardware is more problem prone since it violates the KISS rule.
A diesel hybrid SUV should be able to push mid-30 mpg fuel economy in city/hwy travel and would be a torque monster!
That would make the greenies go frothing at the mouth as they try to figure out whether to damn it or praise it [:D]
But seriously, I also wonder how long it is before the hybrid batteries need replacement (at one point, I read at a cost of $2-3K!) and whether the extra hardware is more problem prone since it violates the KISS rule.
As I mentiond earlier, Lexus claims "lifetime" batteries for the RX330. Don't know what theat means when they go out in 10 years.
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<B>Greg</B> Lake Oswego, Oregon, USA
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<B>2006 ML350</b> - Pewter/Charcoal Alcantara/Aluminum; Packages: Comfort, Lighting, Entertainment, Appearance, Airmatic, Sunroof; Options: Nav, Sirius, hitch, heated seats, power liftgate, roof rack; Mods: ML500 skid plates, ML63 20" wheels.
<B>2001 BMW M3 Coupe</B> (5/01 prod.) - Titanium/Cinnamon w/ many mods.
Mecedes must think diesel has a good future. Just read a magazine article saying that they were going to put one in an SLK. It has three turbos, two small ones to get it moving and overcome lag and a bigger one that comes in at higher speeds.
I also believe that the 163 M Class was available with a 4 litre twin turbo V8 diesel in Europe.
Most manufacturers over here are starting to produce 'sport' diesels. The Prius is the only known hybrid over here and I've never seen one on the road.
Some SUVs run on Liquid Petrolium Gas because the Goverment set the tax at 50% of petrol because its less damageing to the environment.
Diesel sales in Europe are artificially pushed by significant government tax incentives. Here in the USA diesel cost the same as gas and there are no difference in vehicle fees between gas and diesel variants, and so we Americans choose gas or diesel based soley on their respective merits. In this fair situation, diesel does not fare very well. I have driven the Mercedes diesels of the 1980's and they were truly awful cars and did not last as long as hyped. Just look for the phrase 'rebuilt engine' in advertisements for used turbodiesels.
The question you should ask is why do are half the European sedan sales remaining with gas engines when diesel costs so much less for them?
DelJ
Quote:
Wolfgang - 3/27/2005 12:46 PM
Quote:
DelJ - 3/27/2005 8:20 AM
It is the new advanced diesels that are unproven and full of hype.
DelJ, I disagree and so do many others. Here's the percentage of diesels sold in a market where Mercedes offers both gas and diesel versions.
I can't comment on mainland Europe diesel prices because it doesn't affect me so I don't care but here in the UK we pay a heavy premium for buying and running a diesel car.
On average a diesel engined car costs close to $2,000 more than petrol, that's even on a Ford Focus. The fuel itself costs 10 cents a litre more and costs about $1.60 a litre. Road tax is $10 more, Income Tax on a company provided diesel car is more than on petrol. Yet it is predicted that more than 50% of cars sold in the UK in the first 3 months of this year will be diesel. Why? Diesel engines can give 30% better economy, they are longer lasting and just as refined as petrol.
Saying that diesel engines are rubbish now because they were in the 1980's is like saying that PCs are rubbish now because the were slow big and basic in the 1980s. Do yourself a favour and have a drive in a C or E class diesel if your local dealer has one.
Americans drive big thirsty petrol V8s because they don't have an incentive not to. Our incentive is 80% tax on fuel.
DelJ, Your evaluation of a diesel engine is falling a little short, today no other engine in practical use offers higher conversion of fuel energy into mechanical energy than a Diesel engine and further more there is ample room for continual improvement in the conversion rate.
Hybrid cars are no new development, the first cars were electric and with the advent of the IC engine a lot of manufacturers produced Hybrid vehicles in the US and Europe at the beginning of the 1900’s.
Hybrids take advantage of two factors, conservation of energy by recovering some of the Kinetic energy and storing it in accumulators which is ideal in stop ago conditions, the second fact is that vehicles are overpowered for average cruising conditions, the extra power being there for quicker acceleration purposes, Hybrids take advantage of that fact by using smaller engines with the subsequent fuel savings and calling for the electric motor as helpers for acceleration or power demands on different ratios depending on several conditions.
Some people point to Diesel/Electric trains and heavy off the road vehicles as examples of Hybrids economy but in reality the reason is power transmission, to get a ten thousand ton train going would kill a typical clutch or torque converter coupler in no time, for that reason electric motors are used, just to get the thing moving, there is no fuel savings for using the combination, in fact there is s small loss of the Diesel engine energy lost by the generator, resistance and back to mechanical energy by the E motors since none achieve 100% even after factoring mechanical inefficiencies if a straight mechanical drive was used.
MAN/White just unveiled a couple of years ago a Diesel engine in the 30,000HP + range for marine use that broke 50% efficiency range, a remarkable milestone.
When speaking of Heavy continuous duty a non existing term in the automobile world there are no energy or fuel savings in the same sense as driving a little light Hybrid car, the closest analogy being if a Hybrid vehicle started pulling a heavy trailer up hill continuously at high rate, in no time the battery energy will be drained and the small main engine will have to overwork in a diminishing curve.
Diesel advocates are looking for that heavier duty availability with the fuel savings coming from higher and higher efficiencies.
Each system has its merits and advantages, the lack of diesel popularity in the US today is due to the unavailability of clean diesel (on average 500ppm of Sulfur in the US vs. 50ppm in Europe) that is not compatible with the new injection systems and NOX and particulate recovery systems and ever increasing emission standards, however they are 95% cleaner than the last generation, on average 30% more fuel efficient than a comparable gas engine, smooth , quiet and lighter, they offer the HP and torque of the big Iron engines of the early 70’s at a fraction of fuel and emissions. VW is racing diesel cars Vs gas engines and is very competitive.
One of the top engines for 2005.
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