Tow Vehicles of the future

[Brian B-P]

While I acknowledge that there are supporters of each specific engine type (just as there are hybrid, electric, fuel cell, natural gas, etc. supporters), I would not assume that everyone falls in one camp. I think there are lots of valuable technical options, each of which should be applied where appropriate. No one technology is the magic solution for all... not even diesel!

[ronsmith100]

There needs to be some perspective here if you are going to do gas millage comparisons.

A diesel engine has more torque per liter of displacement. If it has more torque it can be attached to a heavier vehicle so that performance is equal to the gasoline engine (read non-towing mpg also equal)
OR
It can be reduced in displacement and placed in the same size vehicle so that performance is equal (read non-towing gas millage way better in diesel).
OR
You can have the same displacement with the same weight vehicle and have much higher performance overall with diesel.

No matter what performance curve you are trying to reach, you can reach it with a smaller diesel engine than gasoline engine (as long aw we are not talking about getting power from high RPM as in a turbo Impreza).
That is the biggest singe draw of diesel engines in the future.
An additional draw as already mentioned is fuel consumption in a diesel engine does not fall off as rapidly as gasoline when towing.
And one last thing: it appears that emissions with low sulfur fuel will be easier to control with ultra low sulfur diesel.At least from what I have been reading... and too the horsepower we are currently getting from high RPM gasoline engines is much less eco-friendly than is slower reving horsepower no matter what the fuel being used.

finally I don't buy that you can draw logical conclusions about what will sell here (US) in the future from what didn't sell in the past unless you can nail down the postulates so that they don't move over time (next four years). Times are changing. Diesel will become more popular in the US very soon (admittedly an opinion that is not nailed down with knowledge of future events).

[Brian B-P]

If you keep vehicle for long time it pays back in longevity.

I don't think there's any logical basis for this assumption. Sure, a commercial duty diesel engine will last a long time... but because it is built for commercial service, not because it is a diesel. There is no reason to assume that the high-boost lightweight automotive diesels will last any longer than a gasoline engine of comparable performance, and especially a gasoline engine of comparable weight and performance. If current diesel products are built for longevity as part of the justification of their higher price, or inherit sturdy construction from their commercial origin, that's nice... but it's not safe to assume.

For concrete examples, the old VW Rabbit diesel and similar vintage GM V8 diesel were both variations of gasoline engine designs. If either were forced to produce anything like the power of the gasoline version, they certainly would not have an advantage in longevity; if the Rabbit engines lasted, that might have been because they produced so little power.

On the other extreme, the B-series Cummins in the Dodge trucks is a commercial-duty engine, and literally weighs a ton. I can believe that it is more durable than a gasoline V8 from a passenger car which weighs one-third as much.

[ronsmith100]

While I acknowledge that there are supporters of each specific engine type (just as there are hybrid, electric, fuel cell, natural gas, etc. supporters), I would not assume that everyone falls in one camp. I think there are lots of valuable technical options, each of which should be applied where appropriate. No one technology is the magic solution for all... not even diesel!

Not to quibble but of the ones you listed here only one is an internal combustion engine. That was the thrust of the thread initially.

[ronsmith100]

I don't think there's any logical basis for this assumption. Sure, a commercial duty diesel engine will last a long time... but because it is built for commercial service, not because it is a diesel. There is no reason to assume that the high-boost lightweight automotive diesels will last any longer than a gasoline engine of comparable performance, and especially a gasoline engine of comparable weight and performance. If current diesel products are built for longevity as part of the justification of their higher price, or inherit sturdy construction from their commercial origin, that's nice... but it's not safe to assume.

For concrete examples, the old VW Rabbit diesel and similar vintage GM V8 diesel were both variations of gasoline engine designs. If either were forced to produce anything like the power of the gasoline version, they certainly would not have an advantage in longevity; if the Rabbit engines lasted, that might have been because they produced so little power.

On the other extreme, the B-series Cummins in the Dodge trucks is a commercial-duty engine, and literally weighs a ton. I can believe that it is more durable than a gasoline V8 from a passenger car which weighs one-third as much.

The old Isuzu Pup is a good example of what you are talking about. Those things run forever... but I think almost any diesel jock will tell you that is because of RPM, not bulk. More miles less turns.

[Brian B-P]

A diesel engine has more torque per liter of displacement....

...No matter what performance curve you are trying to reach, you can reach it with a smaller diesel engine than gasoline engine (as long aw we are not talking about getting power from high RPM as in a turbo Impreza).

If this can be considered true, it is only true because diesels work well with turbochargers. Any torque or power advantage comes from the turbo boost; the diesel advantage is that turbos make them work better, while turbos allow gasoline engines to produce more power only at the expense of significant compromises.

This means that the desired tug motor is not just a diesel (which is more complex than a gas engine), but it must also be turbocharged. The end result is a complex, heavy, and expensive engine... which may still be the best choice.

[Brian B-P]

While I acknowledge that there are supporters of each specific engine type (just as there are hybrid, electric, fuel cell, natural gas, etc. supporters)...

Not to quibble but of the ones you listed here only one is an internal combustion engine. That was the thrust of the thread initially.

Natural gas is used as a fuel for spark-ignition internal combustion engines.
"Hybrid" means (in this context) a combination of an internal combustion engine with an electric drive system.
A fuel cell isn't type of engine, but it is an alternative to a gas or diesel engine as the power source.

But the point is that gasoline and diesel are not an either/or choice, and technical solutions include alternatives to choosing between gas and diesel. For a trailer tug, maybe a gasoline/electric hybrid would suit some people's needs better than a non-hybrid diesel.

[ronsmith100]

Natural gas is used as a fuel for spark-ignition internal combustion engines.
"Hybrid" means (in this context) a combination of an internal combustion engine with an electric drive system.
A fuel cell isn't type of engine, but it is an alternative to a gas or diesel engine as the power source.

But the point is that gasoline and diesel are not an either/or choice, and technical solutions include alternatives to choosing between gas and diesel. For a trailer tug, maybe a gasoline/electric hybrid would suit some people's needs better than a non-hybrid diesel.

OMG! this is getting silly now!

Let's go back and start over:
Irrespective of your opinions on diesels this thread was OBVIOUSLY taling about diesel vs gasoline. OK?
If you don't think diesel will replace gasoline then that... *just* that.
I will then say I think you are wrong but then I could be wrong too.

Thanks

[Chester Taje]

[ronsmith100]

If this can be considered true, it is only true because diesels work well with turbochargers. Any torque or power advantage comes from the turbo boost; the diesel advantage is that turbos make them work better, while turbos allow gasoline engines to produce more power only at the expense of significant compromises.

This means that the desired tug motor is not just a diesel (which is more complex than a gas engine), but it must also be turbocharged. The end result is a complex, heavy, and expensive engine... which may still be the best choice.

I am not sure what the protocol in this forum is. Is there a rule about getting in the last word??

TORQUE: the twisting result produced by a multiplication of the linear force (piston explosion) times the distance off center (throw of the journal)... in ftlbs usually.

Diesel engines get their torque from the [b]force of the explosion times the stroke (journal offset) with or without turbocharging. With or without roots blowers.. Diesel has ALWAYS had a more torque than gasoline for the same displacement. and always will. Thats why non-turbocharged diesels were pulling freight all over the world [b]before turbocharging. . If you think that diesels torque advantage is *only* because of turbocharging then... well what can I say? think about the force of the explosion and the throw of the crank and the length of the stroke for a minute.. or so. If you still cant come to grips with this then I will give you my password to diy auotspecs and you can plot non-turbo diesels vs gasoline over forty years yourself.

Once more: diesel displacement to torque ratio advantage ovre gasoline is not just because of turbocharging. Turbo is a simple modern addition. yes simple: it has next to NO moving parts... it is very inexpensive to produce these days... and it allows diesels *and* gasoline engines to become even smaller and more efficient. Turbochargers will be as common as the carburetor was at one time.. and with fewer moving parts.

http://bankspower.com/Tech_somuchtorque.cfm
http://bankspower.com/Tech_dieselperf.cfm

try google and get tons more

[Steve L.]

Diesels have more torque because they run at considerably higher compression ratios (15 to 20:1 compared to typically below 10:1 for modern gas engines using regular octane fuel). It's not that the diesel is more combustible than other fuels, it's because it's compressed to high enough pressure to ignite on it's own. The higher compression results in higher forces on the crankshaft. Also, the nature of the ignition of the fuel is more efficient than ignition by a point source (spark plug) and requiring flame propagation.

[ronsmith100]

Diesels have more torque because they run at considerably higher compression ratios (15 to 20:1 compared to typically below 10:1 for modern gas engines using regular octane fuel). It's not that the diesel is more combustible than other fuels, it's because it's compressed to high enough pressure to ignite on it's own. The higher compression results in higher forces on the crankshaft. Also, the nature of the ignition of the fuel is more efficient than ignition by a point source (spark plug) and requiring flame propagation.

Steve you are right but there is something else that defines torque besides just explosive force. Namely, the distance that the crank pin is off center.

Put another way the larger crank throw increase the torque for the same piston energy.

You can kinda visualize this if you imaged a four inch piston and rod connected to a one inch throw. Way too tiny to get much torque.

[Steve L.]

Steve you are right but there is something else that defines torque besides just explosive force.

True enough. I was just making a point about why, all other things being equal, the diesel has more torque.

[John Mc]

This discussion has seen some sound theoretical points, which I won't repeat. But back down to where the rubber meets he road. I've driven a turbodiesel VW for four years, though I haven't towed with it. Allow me to briefly review the pros and cons I've experienced (and heard pronounced). This information is culled from my own experience and regular study of sites like the truthaboutcars.com, biodieselnow.com, and tdiclub.com.

In favor of diesel, in no particular rank order-
- The engine turns fewer RPMs at speed, so it's quieter and ought to last longer
- The power is available at low RPM's, allowing more acceleration with less shifting
- The turbo cancels out any altitude-related power loss, even up to Colorado's highest passes
- You get higher MPG because, in part, the fuel packs more energy per gallon
- The higher cost of diesel in my area (+15%) is far outweighed by the MPG increase (40%) I get over the same car with a gas engine (which also had a more efficient manual transmission, so controlling for the TDI's inefficient automatic would predict over a 50% advantage for diesel).
- Modern diesel produces fewer unburnt HCs, less Co and CO2, and has virtually zero evaporative emissions from the fuel tank
- Professionally refined, vegetable-based biodiesel is commercially available, if you know where to look. It can be used in all diesel engines at 20% concentration, and many cars (such as mine) work very well at concentrations up to 100%. Biodiesel is the most energy-efficient liquid biofuel, far better than corn-based E85. It reduces emissions and delivers lubrication to engine parts. And it's so pure, it's not even considered a hazardous waste.
- Diesel cars command a healthy premium on the used market, both because demand far exceeds supply and for the common perception that they last longer. (A six-year old VW TDI with less than 100,000 miles on the clock can command 50% of the original new car price.)


And the cons of diesel-
- Diesel fuel doesn't enjoy the cold, and biodiesel really wants to head south in winter. I'd recommend using no higher a bio percentage than the nighttime low temperature (50% if it drops to 50, 20% where it's down to 20 degrees) to be on the safe side. Refiners put anti-gel additives in their winter fuel, but I add more with my bio blend. It's a good idea to keep your AAA membership up to date. This diesel foible is of no importance to sunbelt owners, but if you live north of any part of Canada, it might not be worth the trouble.
- Another cold weather issue: my car's engine is so thermodynamically efficient that it takes about 3x longer than my gasser to warm up and produce heat. (Newer TDIs have electric elements in the heater duct to speed this process.)
- Even the most modern diesel engines can be really noisy at cold start, and still noisier than gassers at idle. At speed, however, the reverse is true.
- You can't be sure that the fuel you need is available at every gas station, everywhere. But you don't see fleets of diesel trucks stranded by the roadside, do you? Here in Denver, those green pumps I seek are found at more than half the stations (and that's plenty, since I get over 400 miles per tankful).

And here's one both pro and con-
- Diesel cars and their problems are different. I can't count on finding competent service at VW dealers, so I've had to find expert independent mechanics. But these are the folks you want under your hood; friendly fellow enthusiasts, not greedy stealership employees trying to make monthly profit quotas. There is a vigorous web support network for diesel owners, too, that collects the combined wisdom and resources of hundreds of individuals.

That's a lot to consider, but for me, the balance has tipped conclusively to diesel. There is a learning curve,but once you make those adjustments, the benefits keep on coming indefinitely.

I don't plan to visit any new car showrooms until either the Subaru Forester or VW's new small SUV come to market; then, we'll see...

[peterh]

. . .
- Professionally refined, vegetable-based biodiesel is commercially available, if you know where to look. It can be used in all diesel engines at 20% concentration, and many cars (such as mine) work very well at concentrations up to 100%. Biodiesel is the most energy-efficient liquid biofuel, far better than corn-based E85. It reduces emissions and delivers lubrication to engine parts. And it's so pure, it's not even considered a hazardous waste.
. . .

One of my local gas stations (A Shell station) sells bio-diesel, B-80 during the summer (warmer) months and B-50 now during winter, as well as traditional diesel. They have a sign up on their building advertising it, but (interestingly) you really have to look around to find the pump. I had to ask the person inside where it was located.

It turned out that their Shell distributor won't allow competing products -- and bio-diesel qualifies as a competing product -- to be sold by a retail station if the other product's pump is in line-of-sight of the Shell pumps. The bio-diesel pump is, therefore, located on the side of the station where it is least visible from the street.

The legislation that just passed and which the President signed made this practice illegal.

--Peter

[John Mc]

Peter, the places I go to get bio in Denver are really interesting. One's an "oil company," a warehouse for various petro products with an island of high-pressure truck diesel pumps out front, in a suburb called "Commerce City" (the name says it all). The other, in the noted brewery town of Golden, Colorado, calls itself a "drilling supply" company, but it looks like a junkyard. The only thing that looks like it still moves or sells there is the container of Blue Sun Biodiesel. They tell me they go through several 200-gallon cubitainers per week.

Odd places to hang out, eh? But think of all the money I save because they don't have the tempting snacks of a regular gas station (so they're free of the "Twinkie Tax"). I also buy 30 gallons extra in gas cans, so I don't have to visit more than monthly. Out here, most biodiesel is sold to governmental fleets to run school buses and the like. In other parts of the country, I understand it's more readily available.

For a list of local retail biodiesel sources, use this link: http://www.biodiesel.org/buyingbiodiesel/r...es/default.shtm