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Diesel Hybrids in our future?

I am wondering if anyone has heard why there is no diesel hybrid? It seems a natural to me (now that diesels have been cleaned up).

They get better mileage and now start quickly, etc. A diesel seems an ideal solution for the Volt, where the engine’s purpose is to charge the electric batteries.

Also, home-brew diesel is easier and safer than home-brew gas.

Love the show…


One would certainly think.

corperate logic = oxymoron

Any small engine to turn the generator that recharges the drive battery would do, theoretically. Why don’t they ? Will they ? Diesel, biodiesel, alcohol, Mr.Fusion.

When I bought my Escape hybrid I was aghast and confounded that it is not even offered in Ford’s own flex-fuel configuration.

Simple - cost. If a hybrid costs about $3,000 extra, and a diesel costs about $1,500 extra, then a diesel hybrid could cost $4,500 extra. Say you take a Prius at 50 mpg and add diesel to get 75 mpg. Over 100,000 miles you use 2000 gallons with the gasser, 1333 gallons with a turbo diesel, a savings of 667 gallons, $1,333 dollars at $2/gallon. No payback after 100k miles.

I have heard of a few planed, but I don’t know if they will reach North America.

I want a high mileage car that follows KISS. Is this too much to ask for? When only 1 man in 10 at the Dealership can use a multimeter (OK maybe I am exagerating but take a look at where American students place in math and science) aren’t we on the verge of overloading these people?

Think about the amount of computers and turbos and injectors and batteries and motors and…

I don’t think that hybrid technology will help a diesel as much as it does a gasoline engine.
Gasoline engines have a very high idle fuel consumption compared to a comparable diesel, as much as 3 or 4 times as much so shutting off a diesel doesn’t save near as much as shutting of a gas engine does.
There’s still the advantage of energy recovering braking but that can be rendered moot if you get out of the habit of accelerating towards each and every red light.

I don’t think that hybrid technology will help a diesel as much as it does a gasoline engine.

That’s a very good argument. I read an article a couple months ago about the Hybrid pickups and how many people didn’t think they made much sense because they are only increasing gas mileage by 2-3mpg…However when you look at the % increase in these hybrids…it’s MUCH higher then the increase in say the Civic hybrid. A 3mpg increase on a pickup that only gets 15mpg is a 20% increase in gas mileage…THAT’S HUGE.

A motor in a hybrid currently available assists in moving the car and charging the battery pack. Next generation cars like the Volt use the gas/diesel motor only to charge the batteries, the electric motor(s) move the car. In this case the gas or diesel motor runs at a set speed, and it is either on or off. Idling is not an issue, speed and smoothness of restarting and stopping the motor become important factors. People in the car don’t want to hear, feel, or notice when the gas/diesel motor starts and stops. This should be possible in either gas or diesel, but if a gas engine is stopped at just the right point it fires up again very quickly. At this point advantage gas.

Perhaps we may see the wankel type rotary engine again someday. They are very smooth, low weight, and great power to weight ratio. There are technical issues to perfect with them but they could be worked out. A smaller gas engine allows more room in the engine bay for electric motors and battery packs so the passenger and trunk space can be maximized.

Agree; these very high mileage vehicles only make sense at very high gas prices and for high mileage drivers. Where I live the cab drivers are now switching wholesale to Prius vehicles. They put on 100,000 miles a year or so, with a lot of stop and go city driving. A diesel hybrid option would pay for itself after a little over a year for them. The current taxis are mostly Crown Victorias, getting an average of 20 mpg on regular gas. Using 5000 gallons per year @ $2= $10,000 in fuel compared to $4000 for a Prius is a complete no-brainer of course.

Personally, my driving (in my own vehicle ) is down to 7000 miles per year. Last year I spent $859 on gas, so a gas Prius will save me about 60-70 gallons per year or $120-$140 over my 4 cylinder Toyota. The payback for me for a Prius ($9000 premium) is 64 years at $2/gallon and only 32 years at $4/gallon.

Diesel hybrids are being developed by all European car makers, since diesel is priced much lower and gas prices were $8/gallon last year. We need to go back to $4 gas in North Amercia for diesel hybrids to make any sense.

Developing a diesel hybrid would be an inefficient use of resources.

In terms of fuel savings, let’s say making the Prius into a diesel hybrid lets you increase from 45 MPG to 70 MPG. That will save you roughly 79 gallons per 10,000 miles. However, increasing fuel economy from 12 MPG to 15 MPG in a larger vehicle will save you about 167 gallons per 10,000 miles. So the focus should not be on increasing fuel economy in vehicles that are already relatively efficient. Much more fuel will be saved by making large vehicles run more efficiently.

“So the focus should not be on increasing fuel economy in vehicles that are already relatively efficient. Much more fuel will be saved by making large vehicles run more efficiently.”

Exactly - people get mpgs wrong, a 20% boost in mpgs have much greater impact at 12 mpg than it does at 50 mpg, in terms of gallons per 10,000 miles. Europe gets this right by using consumption figures instead.

but will KISS tow it behind their tour bus, or will they drive it to their concerts?


Kinetic energy recovering braking (KERV) is something that would really help heavy vehicles that constantly start and stop. KERV does not nessesarily have to be electric, I believe Ford was working on a compressed air/hydraulic system for use on mail trucks, garbage trucks, city busses, and other heavy vehicles that have to stop and reaccelerate every 100 ft or so.

Rotary engines are fuel hogs, though.

Yes, but in this application you only need a small motor and it runs at a constant speed. Part of the Wankels problems were sealing up larger cylinders, and now the motor can be smaller and the rotory piston has reduced mass. The fuel efficiency can be addressed with application of computer technology and advanced FI systems that were primative in the days of the early wankel motors. Not sure it would work, but worth some research effort.

Actually, I think VW showed one at the recent NY Auto Show.

In Montgomery county, MD (just outside of DC) we have hybrid Diesel-electric metrobuses. The county made a big deal about how much they paid for them 3 years ago. But looking at them now, they are part of the GM hybrid line - so does that mean they fall into the category of the “misguided hybrids”?

Can you provided any info. on how the buses have been working out? Have they been breaking down a lot or are they experiencing problems strictly related to the fact they are diesel-hybrids? Did someone grossly over pay for the buses? How much did they cost and can you describe the buses? I think we can analyze the data and conclude ourselves if they fall into the catagory of “misguided hybrids”.

What is the minimum cost for a one way bus trip in your area? Here in Tucson it is $1.00. Can your public transportation pay for itself from fares?

Diesels have bad image in US.