Why aren't diesel hybrids being used?

[OilFilters]

Originally Posted By: Cujet
Interestingly, the thermal efficiency of gasoline engines in hybrids approaches that of the diesel. Toyota's most modern engines achieve 41% thermal efficiency. This is done through a variety of "tricks" (such as the modified Atkinson cycle) that are not easily employed on non hybrids (due to lack of torque and so on) . Remember, the electric motor(s) make up for lack of torque.


I think this is probably one of the main reasons. If they put a diesel in a Prius, for example, it wouldn't really be much more efficient, but it would be a lot more expensive. Add to that the fact that diesel fuel is now often more expensive than gasoline and it's a real turn off.

The EPA, in their infinite wisdom, thinks diesel is bad. So do a lot of the tree huggers that buy hybrids. It's just an image the manufacturers don't want, especially after the whole VW mishap.

Personally, I would LOVE to have a diesel electric truck. Something with a generator mode that could be used on job sites, or for camping would be FANTASTIC! It's just too bad that modern diesels have to be so freakin' complicated, and therefore expensive and less reliable.

 

[Dyusik]

I have seen lots of diesel hybrids for sale. In Germany.

 

[Cujet]

The original VW XL-1 was a 300cc one cylinder, diesel plug in hybrid with incredible MPG. Later versions had 2 cylinders?

https://en.wikipedia.org/wiki/Volkswagen_1-litre_car

https://www.caranddriver.com/reviews/2014-volkswagen-xl1-first-drive-review

 

[spackard]

I've thought it was a good idea, something that was going to come to commercial trucks.
But, I bet the NVH is very noticeable in a passenger car when the diesel kicks on.

 

[OilFilters]

Originally Posted By: spackard
I've thought it was a good idea, something that was going to come to commercial trucks.

Probably will when the Tesla truck fails for being too expensive with too limited of a range. Batteries and electric motors are getting cheaper all the time.

The problem with trucks is when you add those extra components it takes away from the capacity to carry paying goods. Also hybrids aren't as good on the highway as they are in the city. As lithium batteries become cheaper I bet it will be more common. Some Fedex trucks are diesel hybrids, and as said above a lot of city buses are going this way.

A lot of big fleets are moving towards CNG and LNG, which can actually be cheaper than charging an electric vehicle, while still using standard spark ignition engines.

 

[Linctex]

https://www.google.com/search?q=diesel+electric+hybrid+car&oq=diesel+elcric+hybrid+car&aq


https://www.torquenews.com/1083/why-are-there-no-diesel-hybrid-cars

https://www.greencarreports.com/news/108...se-as-you-think


https://oilprice.com/Energy/Energy-General/300mpg-Diesel-Electric-Hybrid-Unveiled-by-Volkswagen.html

 

[goodtimes]

Regeneration plays a part in hybrid electrics, net efficiency is not so simple to calculate.

Allison developed a Prius style drivetrain before Prius.

http://www.allisontransmission.com/transmissions/hybrid

You aren't going to stop the tree hugging, not even Cummins is anti tree. Change the channel already.

https://www.cummins.com/electrification

Made in California, USA.

https://www.gillig.com/beze

 

[The motor guy]

A diesel hybrid would be disastrous. The way the emissions are setup on these things, they can't be shut off and restarted all the time. They need to be run long and hard to remain problem free, even then they're still a pita.

 

[The motor guy]

maintenance wise that is.

 

[Shannow]

re hard starting, NVH, whatever by people who don't have diesels...

 

[mx5miata]

Chevy volt design minus the diesel

 

[mx5miata]

I would like go see a hybrid with propane generator like the city transit bus

 

[DdDd]

Hybrids are already more expensive with double drivetrain. Add in the diesel engine and higher fuel cost and it's a wash.

Also fuel economy is a diminishing return.

In 100 miles:

From 10mpg to 20 you save five gallons. That's yuuuge.
From 20mpg to 40 you save only 2.5 gal
From 40 to 80mpg you only save 1.25 gallons.

Big mpg numbers may look impressive on marketing materials but saving an additional $150 year by adding a $3k engine option is dumb. Even in Europe where diesel is half the cost of gasoline you don't see hybrids combined with diesels. Either/or.

 

[Nitronoise]

might be a little off the track but my company uses hy bred reefer units run on 480 volts in the yard and we switch them to diesel until we get to the other plants and plug them back in again

bosses figure with a fuel spend of over 175 k shouldn't take long to recoup our cost for the technology

 

[Shannow]

Originally Posted By: DdDd
Hybrids are already more expensive with double drivetrain. Add in the diesel engine and higher fuel cost and it's a wash.


Have you looked at the complexity of a Prius drivetrain versus an engine and a six speed slushbox ?

Get more MPG on diesel, so cost per mile is often better (in most of the world)

 

[ZZman]

I wonder if the engine cost would be that bad if you only used a 2-3 cylinder motor?

 

[Shannow]

Originally Posted By: ZZman
I wonder if the engine cost would be that bad if you only used a 2-3 cylinder motor?


Given that the new generation of engines are
* direct injection
* multiple injection events per cycle
* turbocharged
* high compression

And as I've stated before run on either gasoline or diesel (modern car/truck engines are NOT the diesel engines of old)...the cost differences are SFA.

 

[lovcom]

Originally Posted By: Shannow
Originally Posted By: DdDd
Hybrids are already more expensive with double drivetrain. Add in the diesel engine and higher fuel cost and it's a wash.


Have you looked at the complexity of a Prius drivetrain versus an engine and a six speed slushbox ?

Get more MPG on diesel, so cost per mile is often better (in most of the world)


Just to be clear, the Prius is Toyota's most dependable car they make. This is remarkable because the Prius has the most complexity of any other Toyota vehicle. Toyota's are the most dependable cars in history.

Additionally, the cost of hybrids are the same as most conventional cars of same size and mission. Cost is no longer a reason to buy a conventional car.

I have a 2014 PriusC and I average 50 MPG on freeways, 60 on highways, which is much better than the advertised efficiency. We bought two brand new Prius C's and the out the door price was $18,100 each. So the Return on Investment when buying a hybrid over a conventional is pretty huge, and in most cases.

Putting a diesel in a Prius would be disastrous in my opinion for the added weight, the higher dirty emissions, more complexity, and the fact that diesels do not like being started and stopped 100 times a trip to and from work.

 

[SeaJay]

At the present time manufacturers do not perceive a strong demand for that combo. If and when they do, it will be built.

 

[supton]

I suspect it fails in power/pound, but I wonder if a NA diesel could work ok. I mean, an Atkinson cycle works ok in a hybrid, losing power/pound for the ICE because the whole package works so well. Well, could a lower output diesel work ok also? Fueling can be ramped up to limit/eliminate smoke. I suspect--pure guess on my part--that the electric motor would have to be oversized, as the ICE would be slow to ramp up power output, and to combat weight it might be (relatively) low output. Which I'm not sure gets a net gain.