I have heard this from a cousin who races off road vehicles, he says that he uses a diesel because it has more torque. Also, the big 18 wheelers are diesel as are high tension power generators, locomotives and big ships for that matter. So on the face of it, it seems that if you need lots of power in the same space, you would specify a diesel engine. Is a 2 liter diesel engine more powerful than a 2 liter gas engine? If so why.
Thanx.
Janx.
JUst a stating point, Janx:
It helps to understand the difference between torque and power. The lower half of this message addresses that: http://autos.groups.yahoo.com/group/honda-hybrids/message/60
And here’s some basic stuff:
http://more.abcnews.go.com/sections/tech/Geek/geek000224.html
Simply marvelous. So the next question is: Why do we still have gasoline engines since diesel fuel is chaper and the engine more efficient? It sounds like one answer is the stoutness required for the diesel engine to contain the higher temps & pressures, but given the composite materials available to us would it not be possible to produce a ceramic/kevlar engine block that could do the trick?
Pump diesel is not cheaper than normal gasoline anywhere I’ve been lately. 
Plus there’s that whole particualte emissions bugaboo as well.
Diesel engines work just fine with cast-iron blocks; there’s no need to even bring up alternate engine materials, as that’s not the limiting point. People have been using diesels in automobiles for some time now, after all, and they are not uncommon in small cars in many countries.
Diesel engine isnt more powerful, but they develop more torque. That’s the basic answer to this thread. Diesel engines are less powerful.
Diesels don’t start well in the cold. A block heater is required, and some people don’t like the added hassle of plugging in their car at night.
Diesels have a higher emission of particulates.
Diesels have a rather distinctive sound that a lot of people don’t like.
Diesels have higher torque, but not as much power at the high end as a gasoline engine.
That said, I’ve seen a lot of diesel cars over the years. Volkswagen has made many different models, as have Mercedes and Volvo and I’m sure a lot of others that I’m not thinking of at the moment. They aren’t all that rare, but they aren’t going to replace gasoline engines any time soon.
It’s my understanding that a diesel engine can run on used french fry grease with very little (if any) modification. I read about one guy who gets all the local fast food grease that they would otherwise toss out. The restaurants get free grease removal and he gets free fuel. Apparently all he does is strain the chunks out, and the only down side is that the car apparently stinks like a fast food restaurant.
Last month the sale of diesel engine cars outnumbered that of petrol engined cars for the first time here in the UK. One reason is the tax rules for running company cars. The tax is based on CO2 emmissions. This is lower in diesel engines and so you pay lower road tax and income tax on the use of a company car. In the climate we have here you do not have to use block heaters on cold days. All new diesel engines have glow plugs to heat the fuel when it is cold. With modern turbo diesels the acceleration and overall performance is ( almost ) as good as a petrol engine.
Last month the sale of diesel engine cars outnumbered that of petrol engined cars for the first time here in the UK. One reason is the tax rules for running company cars. The tax is based on CO2 emmissions. This is lower in diesel engines and so you pay lower road tax and income tax on the use of a company car. In the climate we have here you do not have to use block heaters on cold days. All new diesel engines have glow plugs to heat the fuel when it is cold. With modern turbo diesels the acceleration and overall performance is ( almost ) as good as a petrol engine.
If torque is what you need, Diesel’s where it’s at. Years back I ran a Diesel rototiller built in the '50s. That thing was unstoppable.
The cold weather problems with diesel aren’t limited to starting. We lived in Wyoming for 20 years and it wasn’t uncommon to see trucks stopped along I-80 due to the fuel geling from the cold. Overnight lows of -40 and colder were fairly common. It’s my understanding that trucks that are routinelydriven in that kind of weather have heaters in the tank to prevent geling. Most of the ones you’d see stopped were from warmer areas.
Indeed, because anywhere it gets that cold in winter sells winter diesel during the cold season - it’s thinner and doesn’t gel, but this at the cost of a bit of efficiency and power.
My 81 Rabbit starts without being plugged in down to about -15C, though it really complains at anything below -5C. Normally I try to have it plugged in for anything below freezing, but it’s not always possible. This is substantially worst cold-starting performance than a gas engine, but more modern diesels start a lot better in cold conditions than my old junker does.
Diesel engines have a smaller torque curve vs a gasoline engine. A diesel is most powerful and efficient within that curve, that is why large trucks have so many gears in their transmissions. IMHO a diesel engine would be ideal for hybrid technology in automobiles as it is already being used in locomotives
No it didnt. That was just in the executive class - big gas-guzzlers.
Sorry I must have misread the article but the proportion of petrol to diesel cars must be almost even for a wide range of cars.
I have just looked at a couple of news sites and the actual proportion of petrol to diesel new cars in the UK is now 70% to 30 % . In Italy it is now 52% diesel and 48% petrol. I hope that clears that up 
Fuel prices:
In the summer, when vacationers increase the demand for gasoline, diesel is usually cheaper than regular unleaded.
In the winter, heating oil use drives the price of diesel up to or above that of premium unleaded.
Sorry for the lack of attention here gang, the link that explains the difference between torque and power isn’t working for me, (I don’t want to join the group), however I think this is the real question. I have been aware of the design differences between the 2 engine types for years, but that never explained why one would be prefer diesel over gas when one has lots of work to do Vs. Just tooling around town. Also why is it (sometimes) considered better for off road use, when the vehicle is simply pulling its own weight, no trailer, no extra equipment etc. In short I still don’t understand why one is better then the other under load.
There are historic reasons which are peculiar to Europe. While in the USA the price to the consumer is about the same for both fuels because they are taxed similarly, in Europe gasoline has historically been much more expensive because it was taxed much heavier than diesel.
Until quite recently diesel motors were not suited for family cars for a number of reasons. They were heavier, more expensive to purchase and maintain, noisier and less responsive. This meant family cars used gasoline and diesels were used in applications where they were better suited for like buses, trucks and machinery. For this reason governments taxed gasoline as a consumer commodity and had lower taxes on diesel as a production commodity.
Buying a car with a diesel engine required a big increase in investment which could only be recouped via lower fuel expenses if you put very heavy miles on the car. Add the fact that it was a car which would be noisy and have little pickup and you can see why few were sold. . . which made them even more expensive.
Vehicles like taxi fleets were often converted to diesel or propane because they were being operated for so many hours per year but for private cars it did not make much sense.
This may be the case on the mainland of Europe but for the last few years the price of diesel fule in the UK is usuall a penny a litre more than for lead-free petrol . Even so many people still find it worth while to run a diesel car because of the better M.P.G and the resale value of second diesel ( ie lower depreciation ) is higher.