World's Only Diesel-Electric Honda Insight

Jake Staub writes "Just replaced the gasoline engine in a Honda Insight with a Diesel engine. On a 3,000 mile cross-country shakedown journey the car averaged 92mpg over 1,800 miles. Around a very hilly town in Northwest Washington, the car is averaging 78mpg. These mileage averages are without the electric side of the vehicle fully functional. With a bit more tinkering on the electric side and through a slight gearing change through tire size, it is anticipated that the car will likely average 100mpg. The build for the car has been documented on the web site and is as close to open source as my time allows. The car was built by two guys in a garage in Southern Maryland. If we can do it I don't see any reason why major auto manufacturers can't do it since we used their parts."

Comments

Because ..

[OzPeter]

For various reasons the industry in the US has shunned diesel for private vehicles. That has to change before any headway can be made.

Re:Because ..

[eln]

Volkswagen is trying to change that with their Jetta TDI. They ran a bunch of basically infomercials with the Mythbusters guys after each episode for a while trying to "bust the myths" surrounding diesel engines. Time will tell if their marketing campaign is successful, but I would love to see a diesel engine car make some headway here. Personally, I figure I'll be in the market for a new car in 1 or 2 years, and if the Jetta TDI is as good as they want us to think it is, I'm leaning pretty heavily toward it at this point.

Re:Because ..

[east coast]

For various reasons the industry in the US has shunned diesel for private vehicles.

Maybe because the public has shunned it?

Let's be honest here, the industry will do what the public wants when the public votes with their dollars. Diesel could be the answer to the problem but it's also perceived as a problem in and of itself with the public. For the industry it will take less for them to build a technology than to dispel the FUD around an old technology.

And even above the FUD it's hard. At least in my case. I was looking into diesel over a decade ago and good information was hard to get. It was a scary beast when I heard the stories of the fuel gelling, the cost of diesel and engine block heaters. Even with all of this what ended up killing it off for me was that I could only find one service station within 5 miles of my house that had diesel. It made me wonder just how hard it would be to fuel my car in a pinch.

Today I would be less apprehensive but given that I have a newish vehicle and in expect to see a swing in the market before I need a new one I guess it's a moot point.

Re:Because ..

[tlhIngan]

For various reasons the industry in the US has shunned diesel for private vehicles. That has to change before any headway can be made.

Well, the big issue was diesel was much dirtier in North America (high sulfur content) than in Europe, and a lot of the technologies that make diesel cars behave like gas cars tend to require the clean diesel. These days though, I believe the legislation has made low-sulfur diesel mandatory, which is why we see VW and Mercedes starting to import more diesel cars.

Quite a change, really - drive a heavy SUV that gets 5L/100km or better (probably spewing less CO2 than the little car next to you...). Or the fact that the engine lacks the traditional diesel clatter normally associated with trucks, or hell, doesn't Mercedes have a thing that mixes ammonia or something with exhaust that makes the exhaust even cleaner still?

Re:Because ..

[Andy Dodd]

The main reason is the EPA.

US emissions restrictions are different from Europe. Not necessarily stricter, but different.

As I understand it, US emissions regulations are very strict about particulates and NOx emissions (both drawbacks for diesel. Particulates is easy to solve and has been solved, NOx is much harder.)

Euro emissions regulations are very strict about unburned hydrocarbons IIRC, which is good for diesel but bad for gasoline. They are far less strict about NOx.

Re:Because ..

[kick6]

For various reasons the industry in the US has shunned diesel for private vehicles. That has to change before any headway can be made.

I disagree. Diesel is a BYPRODUCT of gasoline refining. A barrel of oil (42 US gallons), when refined, yields about 19.5 gallons of gasoline and about 9 gallons of diesel. Part of the reason diesel prices got so expensive last summer is because there was no supply. Nobody was buying the expensive gasoline that accounts for more than half of all refined goods, but the big trucks and ships needed the diesel that nobody wanted to make because they couldn't sell the gasoline. Starting to see the vicious cycle? Therefore, if a bunch of people started driving diesel cars, you'd see last summer's diesel prices becoming a bit more permanent. Leave diesel to work vehicles. Cars should run on gasoline. The headway needs to be made in technologies like gasoline direct injection.

Re:Because ..

[SpuriousLogic]

Mercedes uses Urea to deal with the NO2 issue - although Honda was supposed to be using a high-temp plasma to do the same (http://www.autoblog.com/2006/05/27/honda-turning-to-plasma-to-beat-diesel-emmisions/) so you would not need to refill urea/ammonia in the car.

Re:Because ..

[natehoy]

I'm in Maine, I own a Jetta Diesel and I'm thrilled with it, but there are a LOT of stations around here that do not have Diesel available.

Once you get off the highway where the trucks are, I'd guess that about 30% of Maine fuel stations actually sell Diesel. There are entire towns (like Freeport) where Diesel is unavailable anywhere in town.

Fortunately, using it around home I just know where the stations are.

And when I travel, the well over 600 mile range between fillups means that I can always find a station in the 150+ miles between 1/4 tank and empty.

Re:Because ..

[ray-auch]

For various reasons the industry in the US has shunned diesel for private vehicles.

Maybe because the public has shunned it?

Let's be honest here, the industry will do what the public wants when the public votes with their dollars.

The public in general (worldwide) will buy what they are told to by the marketers.

Diesel used to have a noisy/dirty/slow reputation in Europe too (20 odd years ago) and it persisted after the technology improved - but the car mfrs here marketed the hell out of new diesels and economy, economy, economy. They had to - it was the only way they could get their fleet average emissions to meet the EU laws.

The US left a truck-sized loophole in its laws for CAFE targets, with the result that if the mfrs could sell the public a 70's technology truck instead of a car they could avoid having to improve fuel economy at all. What's more, because the truck is bigger (but simpler and cheaper) they can charge the dumb public _more_ for something that costs them _less_ to make.

So what did the US mfrs do? They told the public they needed a truck not a car. And you bought it. Then, having got used to big fat profit margins and not having invested in new tech in US factories, they maintained that the US public "wouldn't buy cars for economy".

Then along came the Japs and blew that argument out of the water with clever marketing for hybrids - and clever targeting of the market (ie. the US). They almost didn't bother marketing the Prius etc. over this side of the pond, and you see very few of them, probably because we already have conventional cars that get better real world mpg without all the extra expensive electrics.

So now, with the US public appearing to want economy cars, and higher fuel prices, recession etc., the US car mfrs are stuck with out of date US factories that make stuff no one wants. They can make the right stuff, they have the technology, right now, because they already do make it. Just not in the US. Ford sells 60+ mpg (yes, US mpg) family hatchbacks... but not in the US. Yes, it's the same Ford.

So, what do they do - pitch for some government money to fix their previous bad choice of direction and lack of investment of course. Now, which pitch do you think they are using:

"we need federal money to upgrade our factories to make the efficient cars we already make in Europe, because we never bothered to update our US factories"

Or

"we need federal money to develop brand new American technology for more efficient cars, and tool up our plants to build them, because the American public won't buy the diesels we sell in Europe"

Yep - they are telling you that you won't buy diesels (which of course you won't, because they won't sell them to you...). If Ford put its latest diesels on US forecourts and set its marketing to tell you to buy them, you would - but Ford won't do that, because they won't get as much money (your tax $) that way.

Something's wrong with this idea

[Anonymous Coward]

The black helicopters need to be sent in here. Gas Mileage like that is un-American. Before you know it, the schematics for the water-car will get out.

Today on mutual of slashomaha...

[Anonymous Coward]

(whisper)When it comes to cars, the slashdotter species generally has absolutely NO idea what it is talking about. Shhhh. Here comes the posters now. Let's watch quietly as they trot out the same old ignorant meme's about hybrids, electrics and diesels.(/whisper)

Re:Today on mutual of slashomaha...

[Critical Facilities]

Obligatory

Please pay your taxes in full

[OrangeTide]

By using less fuel you are shifting the tax burden onto those who cannot afford a high tech vehicle. We should expect owners of hybrids, electric cars and high efficiency vehicles to pay their fair share if they can't manage to pay their road tax through fuel purchases. Perhaps you people should be required to keep a log of your travel distances and cut a check when you renew your state registration based on your mileage.

Re:Please pay your taxes in full

[IQgryn]

Whoosh!

Re:Please pay your taxes in full

[FooAtWFU]

Don't be stupid. I mean, the widening fuel/tax-vs-driving gulf is a legit issue, but if the state wants their road tax money, they're perfectly capable of asking for it. (Demanding, actually). In the meantime, they're giving you a tax break for fuel efficiency, which isn't that bad a thing to do, all told.

And in general, I reject the premise that people are morally obligated to voluntarily donate as great a portion to their income as is feasible to the government (like some of those people who say "you shouldn't take a tax break you don't need") - particularly not giving all sorts of money to the Department of Transportation. There are better ways to serve humanity, people.

Re:Please pay your taxes in full

[MarcQuadra]

I live in a state with one of the highest gasoline taxes in the union, and our gas tax doesn't put a dent in our road maintenance budget, which is already not enough to properly maintain the roads.

Using less gas isn't 'shifting the burden' to those who can't afford a more efficient car, especially since there -are- efficient cheap cars. I bought my small 34 MPG car (on the efficient side for the USA) because I couldn't -afford- anything else.

Your argument tries to use economics as a way to discourage a more efficient system, and also expects consumers to act irrationally in their own worst interests, which goes against some of economics' own principles. You can't have your cake and eat it too.

I heard similar arguments against Cash for Clunkers (which I think is lame, but better than cash bailouts for car manufacturers). People were simultaneously castigating the program for 'destroying the cars that could be given to people who need them' and for 'creating a glut of used car parts that will hurt the market'. You can't simultaneously bitch that the program is reducing and increasing prices.

Also, how much did that cheap gas -really- cost us in tax dollars? I'm guessing that the -real fair market- price of gas is around $5 or $6/gallon, but the fact that we live in a country that has 5% of the world's population and spends almost 50% of the world's military dollars keeps the price of gas pretty low. Using less energy is a -good thing- for the economy, and will ultimately -reduce- tax burdens across the board.

Re:Please pay your taxes in full

[OrangeTide]

Most states had budget shortfalls this year. Road projects are being deferred or outright canceled. If you don't mind driving over potholes, then keep driving your hybrid/electric/whatever. The pollution a car makes has zero impact on the use of the road. If people should get a break, it's people who drive motorcycles which use far less space on the road. Or compact cars which are lighter and damage the road less.

I'm surprised you didn't point out that I didn't attack bicyclists for not paying any tax at all.

Re:Frankly I Recommend Such Things

[Critical Facilities]

significantly cheaper at the pump

I don't think that's correct.

Re:Gutless?

[popeye44]

I'm not saying this one isn't gutless. But current diesel technology allows for some serious horsepower and the acceleration of some vehicles I have been in are on par with other vehicles of their size.

Unfortunately Diesel has a bad name. Partly because many gutless vehicles were made with it. I'd like to know this vehicles specs so I'm off to RTFA.

Re:two words to explain why not ...

[Anonymous Coward]

If we can do it I don't see any reason why major auto manufacturers can't do it since we used their parts

profit margin

fixed that for you.

Re:Gutless?

[0100010001010011]

No, modern diesels are nothing like the anemic POS that GM released in the 70s. Mainly because of the addition of the turbo charger (which diesels benefit greatly from), but common rail, higher injection pressures, advances in metallurgy.

My TDI is quite peppy, mainly because the shape of the torque curve. BMW has a 335d and X5 which they are selling here now. VW and Benz have been selling diesels here almost non-stop since the 70s.

That's why I always laugh when Chevy's ads come on trying to sell me this AMAZING 29 MPG car.

I got 48 MPG in a '86 IDI Diesel (that was a bit weak, but who needs more than 50 HP?)
I get 45 MPG in a '98 TDI diesel that is quite peppy. I have upgraded injectors and a special chip tune. I bet I'm just barely over 110 HP, if that.

Diesel is so obviously better for hybrids

[MikeBabcock]

Diesel engines have always been where hybrid cars should go, its just that in North America, most people avoid diesel and gas stations often don't have it.

Diesel engines afaik have always been more tunable to run very efficiently at specific speeds and are therefore a much better choice for generators in general (and are often used in that capacity). Using a fixed-speed diesel engine to generate electricity for a hybrid vehicle seems obvious, and its been done for both city buses and the military HMMV with great success.

I believe a consumer focus on gasoline has lead to car companies' focus on gasoline-electric hybrids instead of diesel-electric.

Re:Diesel is so obviously better for hybrids

[klocwerk]

Except that you're talking about a series hybrid drive, and only the Chevy Volt works that way at the moment.

The Insight and the Prius are both parallel drive hybrids, which means the gas engine turns the wheels as well as powers up the batteries. The electric turns the wheels sometimes. The Volt's big thing is that it's a series hybrid, the drive is always electric and the gas engine runs at its high-efficiency speed to charge the batteries, then shuts off again.

Meaning that your comment would be correct if all hybrids were series hybrids, but as of now your comment would only apply to the Volt which isn't in production yet.

Re:Diesel is so obviously better for hybrids

[MikeBabcock]

I'm quite certain the Volt is in fact in production at this point, and yes I'm speaking of series hybrid drives but that doesn't invalidate my point at all.

My point was simply about using hybrid drives at all, and the choice to use parallel hybrid drives for gasoline engines stems precisely from inefficiencies.

As another person replied, a series hybrid will never be more efficient than a straight engine, but that's ignoring the charging of the batteries through third party options like regenerative braking, solar collection and wall sockets.

Re:Diesel is so obviously better for hybrids

[Andy Dodd]

Actually, it's just the opposite - due to the fact that they throttle simply by adjusting fuel supply to the cylinders and typically do not have a throttle plate, diesel engines are FAR more efficient at reduced power levels than gasoline engines are.

As a result, one of the two main hybrid advantages (running the engine at peak efficiency) is negated. On the other hand, due to the high compression ratio, diesels are simply more efficient.

The other big hybrid advantage (regenerative braking) is still quite applicable to diesel, and in fact may be far easier to apply to diesels than to gasoline, since "ghetto hybrid" approaches like belt alternator-starter and flywheel alternator-starter can still provide great benefit. (Downshift to rev the engine and get the electric to spin - in a gas engine this will result in engine braking. Diesels don't, and in fact can't without special tricks, engine brake, so having an electric generator tied directly to the engine would still be quite effective.)

Re:Diesel is so obviously better for hybrids

[d3vi1]

The irony is that hybrid diesels would be perfect, but nobody takes the concept to it's true potential.
Diesel electric all the way, like in train engines. A Diesel likes to have a constant RPM at it's peak performance value. Imagine connecting an alternator directly to the engine and giving up the inefficient gear system. Imagine a Diesel engine that is always at it's peak performance RPM, even when there's barely any electrical load on it. That car would be a rocket that goes for free (or almost free). It's also pretty easy to build if you have 2 things:
1) 1x 150kW alternator (it's the right amount) that also fits under the hood along with the engine.
2) 4x 40kW electric engines that you connect directly to the drive shaft (and should also fit in there somewhere).
As far as I know a 150kW alternator is very big (about as big as the engine itself) and the 40kW engines are also huge, but at least in theory this would be by far the best way to bring the top possible performance of an engine to the tarmac. Electricity is the best way to transfer energy between two points and a constant RPM diesel is the most efficient and performant diesel out there.

Re:Diesel is so obviously better for hybrids

[onemorechip]

As another person replied, a series hybrid will never be more efficient than a straight engine, but that's ignoring the charging of the batteries through third party options like regenerative braking, solar collection and wall sockets.

It's also ignoring that the losses through conversion are only in the 5% to 10% range. If the gain from running the engine at a constant speed is enough to offset this loss, the hybrid *will* be more efficient.

Re:Diesel is so obviously better for hybrids

[QuantumRiff]

Actually, any Locomotive built since the 1960's is a series hybrid drive diesel. They knew back then how much more efficient it was to have a finely tuned diesel to run at a constant RPM, and turn a Generator to power the electric wheels. (remember reading somewhere that the transmission needed to get a train to its top speed with the old style engine would way more than the whole locomotive!) Were just now getting back to that.. Kinda sad.. Part of me wonders if the companies have been waiting for some patents on train engines to expire... really, the only thing a Volt does differently than a locomotive is store the energy in a battery, so the engine can shut down when its not needed, which would have added way too much weight to a train a few decades ago, with lead acid batteries..

Re:Diesel is so obviously better for hybrids

[weiserfireman]

Why bother using a drive shaft? Put the 4 eletric motors at the wheels and just run electric wire to power them. Otherwise, I like your idea, it is probably overpowered for the normal driver, but a good idea.

Re:Diesel is so obviously better for hybrids

[evilviper]

They knew back then how much more efficient it was to have a finely tuned diesel to run at a constant RPM

No. They knew it would be practically impossible to build a mechanical transmission to handle the unbelievable loads required of a locomotive... If they wanted added efficiency, they sure screwed the pooch when they designed dynamic braking to use giant resistors, and throw away all that braking power as waste heat.

Locomotive engines certainly don't run at constant RPMs. There's no battery where the excess power would go, nor to draw on when the supply at a given speed is insufficient. It wouldn't work.

Part of me wonders if the companies have been waiting for some patents on train engines to expire...

Direct-drive is more efficient than converting to/from electricity in the best case, and a huge waste in the more typical case a few years ago... Batteries are still very expensive, and were previously astronomically expensive.

Not to mention that, up until a couple years ago, gasoline was very, very cheap, and even major efficiency gains were deemed worthless at the time, and reasonably so.

Re:Diesel is so obviously better for hybrids

[balbeir]

The issue is that US refineries aren't set up to produce much diesel.

Adapting them would be a major investment so I don't think oil companies are very hot on the idea either.

Re:Diesel is so obviously better for hybrids

[bluefoxlucid]

When I don't use my brakes to slow down, I can maintain speed in lower gears on idle. For example, when coming to a stop, I cruise in relatively fast on minimal gas, and plan for a longer braking cycle; Some people keep full accelerator pressure to stay at full speed, and then brake sharply, holding the engine at higher RPMs.

More pertinently, most people tap their brakes to go around curves, or use their brakes and accelerator to control speed. Rather than a brake-gas-brakes-gas cycle, I relax the accelerator to slow down, allowing me to maintain speed without letting the engine spool down and then having to speed it back up again to cruise. Also when going around curves, I downshift, allowing the momentum of the car to drive engine compression and keep the engine speed and vehicle speed higher to avoid the need for further acceleration when leaving the curve.

When you brake, you waste energy you've gathered by accelerating and maintaining cruising speed. More gradual stops and more steady speed reduces the amount of acceleration you need to perform, which reduces fuel consumption. Engine braking also reduces brake wear and increases vehicle control, making drivers safer.

Re:Diesel is so obviously better for hybrids

[compro01]

Does "parallel" not imply being able to operate independently?

The series/parallel difference is how the engine is used.

Parallel means that the engine provides the power to move the vehicle and the electric motor assists in parallel when needed. "full" hybrids can also run on just the electric for a time at low speeds, whereas "mild" hybrids (which use smaller, cheaper electric motors) cannot.

Series hybrids just use the engine as a generator and the electric motor(s) provide all the power to the wheels. The engine has no mechanical connection to the wheels.

Really?

[Radical Moderate]

If the unions have contracts that stipulate what cars the manufacturers can produce, that's news to me. Link please.

Re:Really?

[Twanfox]

That's an interesting slippery slope argument.

Frankly, it has been my experience that if you truly know what you're doing, you can generally carry a bigger price tag for your work. You spend less time doing it, and can do more, or at least more complex. Someone that is cheaper generally doesn't know quite as much, so spends longer to do it, and doesn't have the experience already built up not to screw it up in the process. That experience is a big benefit. There are of course exceptions for those that know what they're doing selling themselves cheaply, but I don't think that's typical.

Having worked at a manufacturing facility once already, supporting their IT Ops, I fail to see why a 'highly paid employee in training' is a negative. IT is often sent to training, and I would hazard a guess that they're often paid more than the assembler on the floor. In my particular case, assemblers were also sent to training in order to assert the value of Standard Work. This would enhance effectiveness of the assemblers by simplifying and streamlining the process and empowering them to make suggestions as to how the process could be done more efficiently. Considering this plant was always falling behind on their quota due to inefficiencies, having workers that know how to speed up the process is of significant value, and that means more money for the company.

Also, a manufacturing method that requires fewer workers doesn't mean that jobs will always be cut. Perhaps a second production line will be opened instead, allowing the factory to produce more with their highly paid, highly trained workforce? Other factors, such as penny pinching and trying to get employees to do more with less often set up the scenario where strikes would happen, or employees feel disgruntled and leave for other opportunities.

Re:Frankly I Recommend Such Things

[modecx]

Yeah, you should have told everyone diesel was significantly cheaper than gas last November/December. You might have got a black eye from one of the guys who actually needs to drive his diesel truck/van to make a living.

Diesel was touching $5.00 a gallon, and gas was hovering around $3.00. It would cost me nearly $60 to fill up my Jetta TDI. By the way, the first fill up in 2002 cost me $16.53.

Re:Frankly I Recommend Such Things

[SpuriousLogic]

The newest diesel engines, because of California, now emit much less particulate than even last years engines (however still more than gas). Also NO2 is much reduced for the same reasons.

Diesel Hybrid?

[lalena]

Since the site has been /.'ed and I can't RTFA, I have to ask... Is this really a Diesel Electric engine (as in locomotives) where the diesel engine is used solely to create electricity and is not connected to the drive train? Or is this actually a Diesel Hybrid?

I'm not all that impressed

[damn_registrars]

The current model VW's that have diesel options (Jetta, Golf, Beetle) can average 50mpg all day long with 4 adults and the AC turned on. The first generation Honda Insight, by comparison, barely fits two grown adults (no back seat at all), and has a much smaller fuel tank. If they did this with the new Insight (their web page seems to have gone up in smoke so I can't tell which Insight they used) it would be a little more impressive, though they would still be dealing with the technical issues that face hybrids that do no apply to diesel.

I for one would rather start with a diesel and tune it to get 70mpg without a trunk full of batteries.

Re:I'd buy this car.

[0100010001010011]

TDI = Turbo Direct Injection (Fuel is injected straight into the cylinders)
SDI = Stratified Diesel Injection. (Same as above, no turbo).
IDI = Indirect Injector. (Fuel is injected into prechamber.) Came with and without a turbo.

Re:Gutless?

[LWATCDR]

All diesels in the 70s where gutless. Heck simple truth was all cars in the US in the 70s where pretty gutless. The 70s was when we where trying to get emission controls to work and computers for controlling fuel injection and spark where primitive or just not available.
GM got such a bad rap on the diesel and for the most part it was unfair.
The GM diesel where sold to people that didn't know how to maintain them and by dealers that really didn't know how to maintain them. People that bought a 300D where used to paying Hans the big bucks. Olds buyers where not.
Also GM didn't put in a water separator. That was shouldn't have been an issue but right then quality of diesel went to crap and you had a lot of failed injector pumps.
Again MB was used to crap fuel and put in the extra filtering needed.

Re:Gutless?

[ageoffri]

I recently traded my 06 VW Golf TDI in on a new Camaro. Let me tell you, a diesel is far from gutless. Thanks to the low end torque of diesel the car accelerates more like a small V6 instead of a I4. I could comfortable cruise at 80 mph which is 5 over the speed limit on the highway by me. When it comes to automotive performance, horsepower determines top speed and torque acceleration.

If I get to the point that I can afford a 2nd car payment or pay off my new car another VW TDI will be at the top of my list.

Re:MPG no longer relevant

[Yvan256]

MPG no longer relevant

That's right. MP4 took over.

Re:Gutless?

[Khyber]

Arco Gas Station down the street from my house - Regular 87 Octane - 3.05/g diesel 2.85/g

this is in Southern California.

Can't capture the same benefit twice

[redelm]

The main reason gasoline hybrids get better mileage than direct-coupled engines is that the gasoline engine is not forced to operate at inefficient points on its' BSFC map (near closed throttle). The engine only runs when needed, and then it runs near its' BEP (Best efficiency point), or occasionally at maximum power which also has decent efficiency. It is not forced to idle and off-idle conditions where the pumping losses are horrible and efficiency s#x (5x fuel for same marginal power).

Diesel engines have entirely different BSFC maps, and do not suffer the same pumping losses (vacuum across throttle plate). Their drop off at idle is _much_ lower than for gasoline engines, so they're great in city-wide European traffic jams. Diesel fuel also is ~15% denser (more heat per gallon) and the higher compression ratio is about 5% more theoretically efficient.

But a diesel hybrid does not have much to gain by hybridization. The BSFC map is much flatter, and the engine restarting power & wear is considerably higher.

Re:Can't capture the same benefit twice

[MartinSchou]

Which is of course why we see gasoline electric locomotives all over the place ...

Re:Gutless?

[0100010001010011]

Diesel IS more efficient.

http://en.wikipedia.org/wiki/Diesel_cycle
http://en.wikipedia.org/wiki/Four-stroke_engine#The_Otto_cycle

Comparing the two formulae it can be seen that for a given compression ratio (r), the ideal Otto cycle will be more efficient. However, a diesel engine will be more efficient overall since it will have the ability to operate at higher compression ratios. If a petrol engine were to have the same compression ratio, then knocking (self-ignition) would occur and this would severely reduce the efficiency, whereas in a diesel engine, the self ignition is the desired behavior. Additionally, both of these cycles are only idealizations, and the actual behavior does not divide as clearly or sharply. And the ideal Otto cycle formula stated above does not include throttling losses, which do not apply to diesel engines.

Using the diesel cycle with other fuels has gotten >50% thermal efficiency in the lab, which is DAMN good IMHO.

http://www.eurekalert.org/pub_releases/2009-08/uow-ga073109.php

Re:Isn't it a feature of diesels that...

[Brett Buck]

Isn't it a feature of diesels that they run best in a narrow RPM range?

        That's a characteristic of ALL internal combustion engines, not just diesels. The reason it has been associated with diesels is that the common applications of diesels are those that lend themselves to narrow-range or constant rpm applications like trucks and diesel-electric trains. You could easily optimize a gasoline or methanol engine for a particular RPM range wtih similar results - a restrictor plate NASCAR motor being a hallmark example. It jusy runs around at an almost constant RPM the entire race, and it highly optimized for both power and mileage.

        Brett

EPA

[John Hasler]

> If we can do it I don't see any reason why major auto manufacturers can't do
> it...

Have your car's emissions tested.

Re:Gutless?

[93 Escort Wagon]

Heck simple truth was all cars in the US in the 70s where pretty gutless.

Okay, this is more about aerodynamics than being gutless but whatever...

I had a 76 Ford Pinto when I was a teenager. My friend and I were on our way up to White Pass to go skiing when some guy in a Dodge Charger goes flying around us at ~ 90mph on a blind curve. Fortunately no one was coming the other way, but a cop was sitting right there. He pulls the guy over, then (as I drove by) flagged me down as well. The cop walks up to me and says "I have the two of you doing 90+ on this mountain road", to which I replied with the truth - I'd been passed on a curve, and may have been right behind the Charger but was not going that fast (probably 55-60, which was within the limit). He give me one of those "I've heard THAT before" looks, so I followed up with "Have you ever been in a Ford Pinto going over 65mph? The thing shakes so hard it'd probably start to fall apart pretty fast".

He laughed and let me go.

Re:Gutless?

[FatAlb3rt]

Diesels still don't put down a ton of horsepower...

What's a ton? My daily driver is cranking out about 400 HP. It came from the factory at around 325.

Re:Frankly I Recommend Such Things

[hoggoth]

If you follow that link and look at the gas-pump shaped chart on the right you will see that Diesel has far higher taxes imposed on it than Gasoline, or put another way Gasoline is subsidized through lower taxes than Diesel. And still Diesel averages only a couple of pennies per gallon more expensive.

Re:Frankly I Recommend Such Things

[Fallen Kell]

And even according to the current price listed on the linked website, diesel is currently cheaper. Not to mention the MPG savings, so if you do it cost per mile, diesel is much cheaper...

Re:Gutless?

[0100010001010011]

Um. Maybe you should google that. Carnot is 0<=n<=1 (theoretically). Last I checked .51http://en.wikipedia.org/wiki/Carnot_cycle
http://en.wikipedia.org/wiki/Thermal_efficiency
http://en.wikipedia.org/wiki/Carnot_heat_engine

For example, a typical gasoline automobile engine operates at around 25% efficiency, and a large coal-fueled electrical generating plant peaks at about 46%. The largest diesel engine in the world peaks at 51.7%. In a combined cycle plant, thermal efficiencies are approaching 60%.

The real story

[name_already_taken]

All diesels in the 70s where gutless. Heck simple truth was all cars in the US in the 70s where pretty gutless. The 70s was when we where trying to get emission controls to work and computers for controlling fuel injection and spark where primitive or just not available.

This is true. The basic scientific research on how to control automobile exhaust emissions was incomplete at the time, and the engine controls available were too primitive. This isn't anyone's fault - technology just hadn't caught up to the needs of the time. The only way to do it was to lower compression ratios, and reduce the camshaft profiles. The pellet-bed catalytic converters of the time were horribly restrictive also. About the only good thing that happened to car engines in the 1970s was the advent of good electronic ignition systems. Turbochargers were not in wide use (or production) for cars, so there were very few turbodiesel cars (mostly MB) due to the cost of the turbo itself. Normally aspirated diesels aren't exactly exciting to drive. (Trivia - when the Porsche 911 Turbo came out, parts of the turbo system were made by Lycoming, the aircraft engine company, because there weren't any suitable automotive turbo parts available.)

GM got such a bad rap on the diesel and for the most part it was unfair.

That's not totally true. There were some basic design mistakes, and a cost cutting decision you mentioned that were the downfall of the Oldsmobile diesel.

The GM diesel where sold to people that didn't know how to maintain them and by dealers that really didn't know how to maintain them. People that bought a 300D where used to paying Hans the big bucks. Olds buyers where not.

Actually, a Mercedes diesel of the time required very little maintenance (on the engine at least). Oil, coolant and filter (air/fuel/oil) changes, and that's about it. You could do it all in your driveway.

Also GM didn't put in a water separator. That was shouldn't have been an issue but right then quality of diesel went to crap and you had a lot of failed injector pumps. Again MB was used to crap fuel and put in the extra filtering needed.

This was a big problem. All diesel fuel accumulates water eventually. Diesel fuel has a lubricity requirement - because it must also lubricate the high pressure injection pump. Water is not a good lubricant. Leaving out the water separator was a cost cutting decision GM would not repeat. The later Chevrolet (designed in collaboration with Detroit Diesel) 6.2/6.5 V8 came with one, and even a warning light on the dash to indicate that there was a buildup of water in the fuel (you would then have to open a valve and drain the water out of the separator.

The problems weren't all maintenance-related. The GM 350 diesel (and the lesser-known 4.3V6 diesel used in the front-wheel-drive A-body cars, unrelated to the later Chevrolet 4.3 gas V6) was designed by reusing parts from the Oldsmobile gas V8. The blocks were made using a high-nickel iron alloy and are very strong - they're often bought from the junkyards by drag racers who want to use them as the basis to build very high powered gas engines. The cylinder heads and crankshafts were pretty much stretching the design limits of the materials they were made of, since they were designed under budget constraints. Cracked heads and broken crankshafts were not uncommon. There are tolerances in the alloy compositions (this is just a fact of life, not a GM problem) - because of this some engines got stronger crankshafts and cylinder heads (basically by chance), and there are quite a few 5.7 diesels still running around. I have a friend who was driving a 1980 Oldsmobile 98 Diesel until a few years ago when the body started to rust out.

The later 6.2/6.5 engines were very durable, because they were designed from the ground up to be diesels.

It is unfortunate that GMs design errors stained the diesel in the US

Re:The real story

[Anonymous Coward]

Is that 65 mpg for the Jaguar in imperial gallons? If so, that's about 54 mpg (US). Also, IIRC, that was mostly motorway driving, which uses less fuel than average driving. This Insight apparently got 92 mpg under similar driving conditions.

Re:The real story

[ottothecow]

Actually the reason they don't do diesels now is that they don't like stopping and starting so frequently. Gas engines are perfectly happy shutting down and picking up right where they left off but with a diesel you are going to run into problems (and maybe emissions issues)...if it was a good solution, the toyota engineers would have figured out how to throw a diesel in your prius.

If we ever get a shift towards series hybrids (think train engines), then diesel is a perfect match.

Re:Gutless?

[EXrider]

GM got such a bad rap on the diesel and for the most part it was unfair. The GM diesel where sold to people that didn't know how to maintain them and by dealers that really didn't know how to maintain them.

Unfortunately, the dealer problems still persist with VW diesels, it's well known amongst TDI owners that the majority of dealers screw up simple timing belt replacements in TDIs way too often. Just take a look in the forums over at tdiclub.com and search for "dealer timing belt". It may be as minor as the injection timing being set incorrectly, resulting in a minor loss of power and MPG's, or they get cheap and lazy and don't replace the idler pulley or water pump, causing the timing belt to break soon after and the valves to crash into the pistons. Good news for me, I never go to the stealership, I work on my own vehicles anyways. Also, taking your PD TDI to an oil change place that doesn't use the correct 505.01 rated oil can cause costly camshaft, follower and injector damage.

There were also some serious design flaws with the early GM diesels, they blew head gaskets and warped heads like crazy. This really damaged the reputation of diesel engines amongst people in the US in general.

Re:Gutless?

[FrozenFOXX]

I've also got a 2003 VW Golf TDI, thing's a blast. It's not a barn burner in a straight line but that doesn't mean you can't do that. Down in Holt raceway we had a guy that'd bring out his F-250 diesel and burn straight kerosene. It was a 1/8mi. track and he smoked *everything*. Funniest thing I'd seen.

But yeah, modern diesels are fantastic. Fuel efficient, plenty of punch, stupid amounts of torque, and best of all diesel's extremely durable and simple which makes it ideal for consumer vehicles. My wife's a diesel mechanic (buses mostly) and trust me you can beat the tar out of a diesel and it'll probably still outlive you.

Comment removed

[account_deleted]

Comment removed based on user account deletion

Re:Gutless?

[Colonel Korn]

The GM diesel where sold to people that didn't know how to maintain them and by dealers that really didn't know how to maintain them. People that bought a 300D where used to paying Hans the big bucks.

My dad's 300D from 1982 has never required any sort of engine work. It's driven 300k miles on diesel and now 100k on vegetable oil. It's got the original transmission, the original suspension, the original brakes (this seems crazy to me, but they're in fine shape), etc. It doesn't have the original battery, filters have been replaced, and the vacuum system that controls the locks is leaky so if you shut down the car and lock/unlock cycle the doors a few times the other 3 doors will stop following the driver's door lock.

His 1994 Ford Explorer gets a new transmission every ~4 years, new brakes every 1.5 years, and required him to work on the engine for a week a few years ago. The brakes and transmission are no longer Ford parts - those failed even more often and the new brand has a lifetime warranty that gets a lot of use. The front suspension needed to be replaced, and when the brakes fail ahead of schedule (they do so by falling off while you're driving if you don't watch them closely enough to catch them a month in advance) there's a good chance you'll cause some damage requiring replacement of the axle if you have to tap the brake pedal as you get off the road.

Anecdotes, but along with similar experiences on 2 other Mercedes and 3 other American cars in this period, they're enough to make him look to the Germans when he wants a new car.

Re:Gutless?

[LWATCDR]

I had only ran into the dreaded injector pump death. That often caused a cylinder to fill with fuel followed by a bent the rod and or broken crank.

Diesel + Hybrid = Expensive

[TheMiddleRoad]

Diesels are more expensive than gas engines. Hybrids are more expensive than non-hybrids. Diesel hybrids are the most expensive of the bunch. The market just isn't willing to pay an extra 8-10k for more efficiency. As it is, hybrid buyers have to wait many years to make up the difference versus similar but non-hybrid cars.

Compare the Honda Fit to the Insight.

Insight Base MSRP 19,800
Fit Base Auto MSRP 15,550
Insight MPG 41
Fit MPG 31

Assume fuel is $4.00 (higher than now) and 15,000 miles driven per year.

So basically, assuming you keep the car, you break even when you've saved 4250 on fuel. That will take 9 years.

So say you take the 50MPG diesel and turn it into a 66MPG diesel. The amount spent on fuel each year will be much smaller in the first place, so it will take even longer to pay off the investment.

Re:Gutless?

[algerath]

Units are not exactly the same. Europe and most of the world, I believe, uses the Research octane number or RON. The U.S. uses the average of RON and MON.
If I remember right RON tends to be 8 to 10 points higher than MON or Motor octane number. The RON MON average used in the U.S. would be 4-5 points lower than the RON for the same gasoline.
87 in the U.S. would be around 91 in Europe
91 or 92 premium in the U.S. would be 95-97 in Europe.

Re:two words to explain why not ...

[phantomfive]

I know it's popular around here to blame corporations and the pursuit of profit as the root cause of everything, but in this case profit margin probably has nothing to do with it. You don't think the auto companies can get the parts cheaper than these guys? Besides that, GM at least has been selling a lot of their cars lately with a negative profit margin, which is why they lose money every year. And the Volt doesn't look like it will be that much better.

Re:Frankly I Recommend Such Things

[Fahrvergnuugen]

And you're TDI Jetta still averaged 50% better mileage than a Gasoline Jetta (45mpg vs 30mpg), so until diesel is more than 2x the cost of gasoline, you're still ahead of the game.

Re:Gutless?

[TheLink]

> Back when Volvo first released their diesel intercooled turbo's here in North America, people were stepping on the gas and wrapping them around trees,

> So no, they're not gutless. If you can get an S70 made before '98 you're in for a happy surprise too.

Like being in a car that's wrapped around a tree?

Good luck on that

[damn_registrars]

But Diesel should have been the initial plan, railway locomotives have been using that setup for decades.

Many American drivers still distrust diesel after the terrible vehicles (mostly large sedans) with big diesels that the big three produced back in the 70s and 80s. For better or for worse, the big three are aware of this and haven't bothered even trying to sell consumer diesels in the US. Unfortunately they also can't find marketing droids that are capable of pulling their own heads out of their own asses, so they will never try to correct the misconceptions.

Hence while indeed a diesel setup would have been a better idea for the Volt, it would have been likely a complete failure for GM.

Re:Gutless?

[Rei]

It's not an issue of "past" versus "present". Yes, modern diesels are far cleaner and more powerful per unit mass than they were in the 1970s. But you know what? So are gasoline engines. Modern diesels still lag well behind gasoline engines in both respects. Show me a single SULEV diesel, for example. The modern "clean diesels" generally barely meet modern US emissions reqs. The only reason they're so widespread in Europe is because they have more lax emissions reqs.

Secondly, this entire thread is based on two huge fallacies.

1) That one driver's (likely hypermiling, and at least anecdotal) mileage reports actually reflect a difference over EPA numbers; and
2) Diesel gallons are roughly equivalent to gasoline gallons.

Both of those are just that: fallacies. Vehicle mileages should only be compared on standardized test cycles, because driving habits from one person to another can vary *dramatically*. And diesel is *not* equivalent to gasoline. It's almost 15% denser and releases correspondingly more CO2 per gallon burned (as well as far greater amounts of many other pollutants). And it's no longer true, thanks to modern desulfurization reqs, that diesel takes significantly less energy to refine, offsetting the difference.

That said, even per unit mass, diesel engines do tend to be more efficient (usually about 15% average in real-world driving). Does the CO2 and operation-cost savings justify the higher release of other emissions? That's a tough call, and depends on how much you value different aspects.

Re:MPG no longer relevant

[DavidTC]

Bingo. Fuel efficiency is a red herring. Especially as fuel efficiency and emissions are sometimes at odds with each other. I.e., adding more exhaust controls to reduce emissions can lower MPGs.(1)

If they just kept reducing the emissions allowed, cars would almost automatically become more energy efficient, as the easiest way to make them emit 10% less is to have them use 10% less gas.

Of course, you have to figure out what emissions, or have some sort of 'unit' system, where, for example, X amount of CO2 equals Y amount of sulfer equals Z amount of unburned gas, and add them all up, and the total has to be under a certain amount.

1) Although a lot of this can be counteracted in other ways. For example, how come no one's ever come up with an exhaust system with electric pressurization help, or at least fans? Using all that spare electricity gasoline cars have flowing around in them from the alternator, instead of having the gasoline engine have to force the exhaust through the exhaust cleaning system? Because car companies never needed to, they can reduce MPGs just as easily by cutting back on those emission controls instead.

Re:Gutless?

[natehoy]

Diesel's come a long way.

My car still made the clickity-clackity noises until it was properly broken in at about 40,000 miles, and it still makes a distinctive sound, but is about as loud as an average gasoline engine.

If I put my foot down, I can make a small cloud of smoke, and of course there's a little smoke at startup when it gets chilly, but for average driving you'd never know you were behind a Diesel except for the TDI badge.

I live in Maine, where overnight temps can easily hit zero and 20 below is not that uncommon - we get a night or two down in that range about every year. If it gets truly cold I might have to wait 30 seconds for the glow plugs to finish their dastardly deed, but I've never had the slightest problem starting it up.

Admittedly, when it's below zero the engine has the power of an asthmatic hamster for the first minute or two. But it gets up to full power pretty quickly.

But, yeah, the taxes have really chewed into my fuel savings. I'm still happy with it, and at 100,000 miles I'm thinking about celebrating with a VeggieVan conversion kit if I can find a reliable source of used veggie oil. A 20-gallon veggie system + 15 gallon Diesel tank would give me a range of well over 1000 miles between fill-ups. :)

Re:Gutless?

[kcfoxie]

You're 100% wrong. The EPAs tests rated my vehicle 31/40. I've never seen less than 38mpg from day one and I drove the hell out of it. I think they drove like a normal person, because the gas Insight could get upwards of 100MPG tailing a larger vehicle. Also the Jetta TDI set the world record for most efficient non-hybrid vehicle in a cross country road trip: 58mpg. As for power; The R10 basically proved that diesels are cleaner, faster and more efficient. My puny 140hp (chipped, 100hp stock) diesel makes 300ft/lb at low RPMs. That means I jump off the line long before your V6 pony gets anywhere near it's peak power -- enough to let me win a 1/8 mile race up to 70mph. I'll get about 38mpg in the process. You will get at best 18.

Re:Gutless?

[rah1420]

Just this past weekend I spent with my brother-in-law timing a 98 Passat TDI with VCDS. It definitely made a huge difference.

Going there it was definitely "gutless" and coming away it was like a new engine. (To be fair, the injector timing was off a fair bit.)

Re:Gutless?

[shiftless]

Something about them being actually petrol engines modified for compression ignition, without realising that the compression ratios would typically be double, which was out of specification for the block.

No, the block was heavily reinforced.

ALL of the Olds diesel problems can be traced back to one idiotic design decision--the lack of a fuel/water separator. That, combined with the horribly contaminated diesel fuel in the late 70s/early 80s, is what led to the Olds diesel's demise.

Re:Gutless?

[pressman]

I was working on a project comparing a Prius to a 2009 Jetta TDI. We drove both from Portland, ME to Portland, OR and you would never know the Jetta was a diesel. AND... on highway driving it destroyed the Prius on gas mileage.

Newer diesel technology is amazingly clean, efficient and powerful.

Re:Isn't it a feature of diesels that...

[Ungrounded Lightning]

Isn't it a feature of diesels that they run best in a narrow RPM range?

That's a characteristic of ALL internal combustion engines, not just diesels. The reason it has been associated with diesels is that the common applications of diesels are those that lend themselves to narrow-range or constant rpm applications ...

Wait a minute. That's misleading.

All engines have some RPM where they have an efficiency peak and for a narrow range around that they are essentially at their peak efficiency (because the slope of a continuous function is zero at the maximums and minimums).

But the Otto cycle (spark-ignited gasoline engine) has a broad peak where the efficiency is near the max while the diesel cycle (compression-ignited) has a much narrower peak. This is largely because the compression heating and mixture requirements for ignition imposed more stringent limits on the amount that the operating parameters of a diesel could be adjusted for power/RPM combination than the spark-ignition of the gasoline engine did. (Better control of fuel injection and turbocharging is improving things for diesels now, though.)

Combine the narrow efficiency peak of a diesel - requiring more gearing in the transmission, increasing weight and reducing time lost to shifts, with its stronger structure requirements to survive higher compression, also increasing weight and impeding rapid RPM change, and the gasoline engine and its transmission had a significant power-to-weight-ratio and accelleartion advantage for passenger cars - at least in the pre-computer days.

Modern cybernetics and materials are putting turbocharged diesels on a better performance footing, while diesels are retaining their fuel efficiency advantage.

But of course for a hybrid - either with a pure electric transmission or an electromechanical one - the diesel's power curve is much less of an issue while its efficiency is a big win. So the diesel is a better match.

Re:Gutless?

[Almost-Retired]

I don't know where you are buying your horses, but where I come from a 400 pound horse is still a yearling colt & likely has never had a bridle on his head. The horses I'm used to looking at the rear end of were in the ton & plus range, each. Percherons of course, King weighed 1950, and Colonal weighed 2200. And there wasn't anything on that Iowa farm including some Case tractors that were considered to be pretty good in their day, but could also be buried to the pto if the young driver, me in this case, screwed up, I buried an LA and 4 16" plows in the bottom of the west 80.

Daddy made a new double tree out of a native cut piece of Oak, 2+" thick and a foot wide. Those two horses with about 80 feet of 1/2" log chain between the double tree and that tractors rear axle, got down on their bellies and picked the middle of that chain a full foot off the ground, and that 9,000 pounds of tractor came back onto solid ground.

Now folks, that was torque. Then we went back and got the plow but it was a piece of cake for that team.

Those Clydesdale's in the Bud commercials? A 1 tonner even won't make the team, most of those are closer to 2400 than 2000 lbs. We used to know the folks who sold Bud a few of those. And Bud was both picky and inadvertantly abusive. That spot showing one galloping in the surf was very dangerous, with their size they don't 'gallup' at all well even on solid land, and a broken ankle from stepping on the hidden bottom wrong were very real dangers to a fine specimen of the breed. I shuddered every time I saw that spot on tv.

Next time you start measuring horses, bring some real horses, not some skittish 400 lb pets/toys.

--
Cheers, Gene

Re:Gutless?

[commodore64_love]

Diesels are not "gutless". They have very high torque numbers which allows the driver to accelerate rapidly on the highway without needing to downshift like a gasoline car needs to do. Put another way - if you take a 110hp Diesel Jetta and put it against a 110hp gasoline Jetta, the diesel will accelerate faster since it has almost triple the torque (rotational force).

>>>I've never driven one, but I am genuinely curious....

Then go to your local VW dealer and drive one. You'll be surprised.

Re:Clean diesel

[commodore64_love]

>>>Here's the most recent one that fueleconomy.gov has

You are such a fucking liar. You've done it twice now, first by claiming a modern diesel only gets a "1" and using old old data. And now again by claiming 2006 was the most-recent available year. False. 2009 Jetta Diesel == 6 on the EPA pollution scale. LINK - http://www.fueleconomy.gov/feg/2008car2tablef.jsp?column=2&id=25262 - That's equivalent to what the gasoline version gets.

And the Diesel has a smaller "carbon footprint" - 11.9 diesel versus 7.3 for gasoline

European countries, which have signed the greenhouse gas reduction treaties, are encouraging diesel and diesel-electric cars as the cleanest technology. Once again the United States is falling behind its E.U. neighbors with bass-backwards antidiesel policies, just the same way its falling-behind in internet speeds, cellphone speeds, and so on.