More Efficiency Please

After years of pestering my father, he finally let me drive a car - at nine years of age. At 14 I taught myself to drive stick shifts and then how to ride motorcycles. Later, I also learned to fly and have had my pilot’s license for 22 years. Working on, riding, driving, restoring, photographing and writing about all these wonderful machines has always been my passion. I've been an auto vo-tech and smog test instructor, certified master technician, vehicle inspector, shop foreman, service manager, service director, and shop owner. Over the years I’ve owned about 35 bikes and 50 cars and trucks, a lot of which I wish I had never sold!

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By Ken Freund | Published 06/3/2008

I just noticed the price of diesel fuel at my local filling station has passed $5.20 per gallon and I literally had to stop and do a double take to be sure I hadn’t read it wrong. I can remember 20-cent diesel fuel, so the shock went right through me, and I keep hoping I’ll wake up and find it was all a bad dream.

It also got me thinking about how these high prices shift the economics of building more-efficient engines and vehicles. Changing designs does cost money, and obviously the manufacturers have to pass this on to the buyers. However, as the price of fuel goes up, changes that improve mileage can pay for themselves in savings sooner than before.

Dodge Rams powered by Cummins diesels are among the most efficient work vehicles that you can buy in their size and weight category. That is, they haul the most weight for a given amount of diesel fuel. However, at current prices, this isn’t enough. If you look to 18-wheelers, you’ll find that their mpg numbers when moving up to 80,000 pounds are not much worse than a pickup truck hauling a fifth-wheel or gooseneck trailer with a combined weight of around 20,000 pounds.

What I’m suggesting is a sort of Manhattan Project to develop drivetrains, running gear, chassis and bodies that are lighter and more efficient, with less internal friction, less rolling resistance and better aerodynamics. Much of the technology can be transferred from heavy trucks.

Pickup-truck engines need to be smaller, lighter and more thrifty. For the Cummins, perhaps it’s time to reconfigure it to a V-6, or even a horizontally opposed flat six (these have perfect balance). This would allow the front end of the trucks be more sloping for better aerodynamics, as well as requiring less metal in the more-compact blocks. Variable valve timing could improve efficiency and mileage. Cylinder deactivation could allow the engine to run on fewer cylinders under light loads and reduce pumping losses. High-tech materials and coatings, along with innovative new designs can reduce internal friction.

Higher-pressure fuel injection, along with high-tech nozzles, could atomize the fuel better for more efficiency. Cooling fans require huge amounts of power. Waste heat from the exhaust and cooling system could also be captured and reused. More gears in the transmission are one of the secrets of how big trucks get better mileage per ton-mile, so maybe it’s time we had more too. It may also be time for a highly-efficient diesel-hybrid version, which could be an option. Regenerative braking can recoup energy instead of turning it to waste heat with our brakes.

With these changes, I think a Dodge Ram diesel could get more than 30 miles per gallon solo and probably 20 mpg towing. What do you think is needed, what would you like to see and how much are you willing to pay for it?

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Comment #1 (Posted by R. Hoesly)

the sooner the better
Comment #2 (Posted by dpuckett)

I agree with the Rams getting 30mpg on a regular basis. I think the secret is to get the EPA off our backs and allow the manufacturers to do what is needed to get the MPGs. It's no secret that anytime we take the next step in emission reduction, MPGs suffer. Add the fact government has their hands deep in our pockets for every gallon we purchase, so they have no real interest in lowering our consumption. Less consumption = less money to spend on buying votes at the next election. I also think lower revving engines- say 23-2500rpm tops- and more gears in the tranny, &/or higher diff gearing would also help. One reason semis get such great economy when comparing weight to MPG vs a pickup is a closer RPM range. Peak torque is around 12-1300rpm, and peak power is usually around 2000 +/-. This allows the cam, turbo, injection system, etc, to be designed to offer peak efficiency under most conditions. You dont sacrifice bottom end spoolup for higher end flow, or give up top end for a good bottom end, because the power band is closer together. This results in more shifting, and possibly slower acceleration overall, but hey, to cut my fuel consumption in half, I'll give up some pep off the line.
Comment #3 (Posted by DodgeWarlock)

I think it says a lot that out of the box my 90 W250 CTD got 22mpg, our 01 2500 CTD 4x4 gets 18mpg and a new one is lucky to get that. No one argues that they need to run cleaner, but what good is that if efficiency drops and they waste more fuel. The more efficient engine is inherently cleaner. The less fuel it burns the less emissions it can produce.
Comment #4 (Posted by Harry)

Good idea; now to get Chrysler into the frame of mind to help test and make the changes.
Comment #5 (Posted by Jack Rathert)

I am patiently waiting for Chrysler to put the new Cummins in a 300C. Then I can trade in my gas hog HEMI 300C in on one. A great car but not too practical in these days of $4 / gal. plus fuel.
Comment #6 (Posted by Will)

$5.00 + per gallon, over $10.00 in other parts of the world says the end of the internal combustion engine is near, time to start designing turbo chips for electric engines, look to the future, don't dwell on the past
Comment #7 (Posted by Bill K)

Ken, agree with new design issues you discuss.
On a more immediate time line those of us current RAM diesel truck owners can do more "small aerodynamic improvements". For example if we assume for every 0.01 improvement of Cd equals 0.1 mpg improvement in fuel economy. Improvements we make to our trucks assuming 15 mpg average at $4.00 per gallon equals for every 100,000 miles a saving of $176.60. Granted small improvements of 0.1 mpg such as removing bug shields, removing mud flaps, removing side step rails, increasing tire diameter and type of tread, adding a tail gate spoiler, running synthetics in engines, transmissions/axles/transfer cases, etc, etc.
We can also do some more expensive aerodynamic improvements to improve on the Cd-drag coefficient. Add a bed cover (hard tonneau cover), install belly pans, install air spoilers "spats", hood replacement, etc. ,etc.
The perplexing problem is it is almost impossible to obtain accurate aerodynamic data from Dodge or other sources in order to determine which areas impact on improving the Cd and the direct impact it has on fuel efficiency.
Can you comment on this?
TDR needs to spend much more effort to bring us members more in depth information on ways we owners can make noticeable improvements to our trucks.
THANKS
Comment #8 (Posted by Road Dog)

Most people don't understand the underlying physics of a piston engine. You're converting pressure to mechanical energy and the maximum theoretical efficiency is around 35%. Guess what -- we're there. The only way to improve the fuel economy is to stop pushing 8,000 pounds of steel down the road. Lighter is better. I really wish there was a little Diesel pickup in NA but the EPA and CARB will never let that happen (it's an emissions thing that bigger trucks didn't have to worry about).
Comment #9 (Posted by Mike)

It's funny how times change. Just a few years ago everyone was hopping on the HP/TQ bandwagon and demanding the High Output trucks. My 2003 Standard Output output truck was poo-pooed by others for only having 250HP/460TQ which would "hurt resale value", but it routinely gets me 22-23mpg highway. Now how is my resale value doing compared to the HO trucks? Not that I'd ever sell it, but it goes to show how things have flipped in just a few years.
Comment #10 (Posted by PAUL)

i believe your correct. Unfortuantly no body is listening at Cummins, they are trying new things but NOTHING is a large enough step to make a differance. They sell a ton of motors, dodge sells a ton of truck no matter what gas/diesel prices are so why take away profit for research. I agree 30mpg is not a very far stretch for any diesel not just cummins BUT again someone would have to care at the MFG plant.

two things i see anyone who can make a 3/4 ton truck get 30 MPG and a mini van dip into the 30's easily and be the first to do so will be the richest manufacturer on the market. What do people need most, trucks and mini vans, what do they want cheaper ways to run both....just my 2 cents
Comment #11 (Posted by Keith)

If my 5 International 9100 series trucks have 9 speed tansmissions in them, then why can we not have a 7-8 speed transmission in these trucks? Is it possible? Or will the added weight be too much to offset the savings? Hey it will be an extra $2000.00 to get it but if the tranny lasts 300,000 miles...money well spent.

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