Diesel Hybrids - why not?
Discussion
Seems to me that the true best of both worlds would be a hybrid diesel so why isn't there any? (or many, if there is the odd one)
Hybrids are their most efficient around town where you are constantly braking and regenerating
Hybrids are their least efficient on the motorway where they don't get a chance to regenerate
Diesels are their most efficient on a motorway
Diesels are their least efficient around town.
Diesel is more efficient than petrol.
WTF ?!
Hybrids are their most efficient around town where you are constantly braking and regenerating
Hybrids are their least efficient on the motorway where they don't get a chance to regenerate
Diesels are their most efficient on a motorway
Diesels are their least efficient around town.
Diesel is more efficient than petrol.
WTF ?!
There are some on the market but my thoughts on why there are not more are:
Diesel engines are heavier than petrol engines and weight is an issue with batteries etc.
Diesel engines really need turbos to be useful but most petrol hybrids manage with na petrols, so cost may be an issue.
Diesel is popular in Europe but other continents prefer petrol so a petrol hybrid is easier to sell worldwide.
Diesel engines are heavier than petrol engines and weight is an issue with batteries etc.
Diesel engines really need turbos to be useful but most petrol hybrids manage with na petrols, so cost may be an issue.
Diesel is popular in Europe but other continents prefer petrol so a petrol hybrid is easier to sell worldwide.
kambites said:
And Mercedes.
I think until recently diesels haven't really been refined for it to work. Plus, as said above, markets tend to go for either diesels or hybrids but rarely both.
Back in the day people had phones & laptops they didn't need a device that sat in the middle.I think until recently diesels haven't really been refined for it to work. Plus, as said above, markets tend to go for either diesels or hybrids but rarely both.
Crazy apple then came along and turned home computing on its head with the iPad.
Sometimes it takes a bold risk to change the way people think. (strapline anyone?)
Pixelpeep said:
kambites said:
It's funny, but I still don't see the point in tablet PCs either. 
Apple sold 26 million iPads in Q1 of 2014 alone. There are a few people that see the point 
Material cost.
Alot of money to build a diesel hybrid so you wont see it in smaller non premium stuff where the volumes are, would require a big jump in retail price hence tend to be the premium or at a puch high spec cars. Not great for engine start stop as the transition can be difficult to mask.
Small cars are moving away from diesels as it is.
Alot of money to build a diesel hybrid so you wont see it in smaller non premium stuff where the volumes are, would require a big jump in retail price hence tend to be the premium or at a puch high spec cars. Not great for engine start stop as the transition can be difficult to mask.
Small cars are moving away from diesels as it is.
HTP99 said:
Diesels take a lot longer to get up to optimum temperature than petrols, so therefore if they are on/off all the time I guess you aren't going to get the optimum fuel economy out of them?
and they pump out a lot more nasty stuff, expect to see them banned in the next 20 years, at least in none commercial vehicles doogz said:
I have no real idea.
I'm sure someone that does will be along soon.
You called? ;-)I'm sure someone that does will be along soon.
The fundamental reason is simply cost. A modern diesel engine is expensive to the OEMs (significantly more than even a DI gasoline). This is because it needs things like DPFs and ultra high pressure fuel pump and injectors etc. The extra cost of a hybrid system and a diesel engine simply make that combination untenable. Unfortunately however, modern gasoline engines are becoming more expensive, as the aftertreatment and emissions requirements are getting ever tighter.
The second important reason is that any hybrid system is expensive (batteries, inverters, motors, chargers etc etc) so if you are going to fit one, fitting a big, powerful one is a good idea (ie one that returns the biggest reduction in emissions and fuel consumption). But, once you have a powerful hybrid system, then the ICEs operating range is much reduced, so when you optimise that, you end up with a petrol engine as a good "fit" (because you only need it to run under certain situations and not across all vehicle speed / load ranges, where the unthrottled / lean running DERV is so good.
Mercedes just showcased theirs - "1,200 miles from Africa to Goodwood. On 1 tank of fuel. The E 300 BlueTEC Hybrid completed the incredible journey with around 100 miles left in the tank!" I believe it's an 80 litre tank:
https://www.youtube.com/watch?v=trag3EWVXR8&li...
https://www.youtube.com/watch?v=trag3EWVXR8&li...
It's market driven to some extent.
For instance, in places like China there is relatively low diesel take-up. Hybrid petrols make a lot of sense over there - sub 3.0l engines that go like V8s meaning cheap to buy and cheaper to run.
Petrols from an emissions perspective lend themselves better to the task as well. A catalytic converter is pretty much it at the moment whereas even a hybridised diesel would still need a DPF and a cat and probably some kind of NOx trap.
Diesel exhaust after-treatment is expensive.
For instance, in places like China there is relatively low diesel take-up. Hybrid petrols make a lot of sense over there - sub 3.0l engines that go like V8s meaning cheap to buy and cheaper to run.
Petrols from an emissions perspective lend themselves better to the task as well. A catalytic converter is pretty much it at the moment whereas even a hybridised diesel would still need a DPF and a cat and probably some kind of NOx trap.
Diesel exhaust after-treatment is expensive.
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