Posted by Ray O on May 3, 2006, 6:19 pm
>>
>> Michael Pardee wrote:
>> <snip>
>>
>> Commonrail diesels are VERY good. Comparable power and better torque
>> than all but the top end petrol model-mates. They drive less like a
>> diesel than old TDs and get HUGE economy. Theyre quiet, not quite as
>> quiet as a petrol I admit, but certainly quieter than an older petrol
>> engine. This is why ive never seen the point of hybrid as a current
>> choice of car, maybe in 10 years when theyve matured.
>>
>> J
>>
> Hybrids work at the other end of the driving spectrum. The only advantage
> they offer on the open road (where diesels shine) is the ability to reduce
> engine size while maintaining passing performance, but in town they reduce
> the amount of time a gas or diesel engine is run in the lowest efficiency
> ranges. Hybridizing with a turbo diesel power plant is a very attractive
> idea - each covering the weaknesses of the other. There is no reason a TD
> hybrid 5 passenger sedan couldn't offer more than 100 mpg in town and 80
> mpg on the freeway, at least at 65 mph. Mainly it takes advances in the
> power electronics.
> Mike
I think the biggest drawback to a hybrid diesel is cost. Both the diesel
powerplant and hybrid power plant cost more than a conventional gasoline
(etrol) engine so a diesel hybrid would have a double cost disadvantage to
overcome.
--
Ray O
(correct punctuation to reply)
Posted by Martin Dixon on May 4, 2006, 4:23 pm
>
> I think the biggest drawback to a hybrid diesel is cost. Both the diesel
> powerplant and hybrid power plant cost more than a conventional gasoline
> (etrol) engine so a diesel hybrid would have a double cost disadvantage to
> overcome.
I would speculate that one problem with a diesel hybrid would be the
extra power needed to crank the engine, remembering that this will
happen quite frequently in a hybrid. This may mean more batteries
(and hence weight) and a heavier engine anyway, meaning that the
engine will need to run more frequently than it would in a petrol
powered hybrid.
The hybrids that I have seen have clearly been designed to minimise
weight, even perhaps compromising braking and cornering performance by
fitting narrower tyres. With present technology, it is even possible
that the extra weight required by a diesel engine would cancel out the
gain in fuel economy compared to a petrol engine.
The one thing that would really make hybrids irresistable would be a
means of charging the batteries from the mains. That way, even less
fuel would be burned (at least by the car). But I doubt the oil
companies would allow that to happen.
--
Created on the Iyonix PC - the world's fastest RISC OS computer.
http://homepage.ntlworld.com/m.dixon4/
Posted by Keith Willcocks on May 4, 2006, 4:30 pm
>>
>> I think the biggest drawback to a hybrid diesel is cost. Both the diesel
>> powerplant and hybrid power plant cost more than a conventional gasoline
>> (etrol) engine so a diesel hybrid would have a double cost disadvantage
>> to
>> overcome.
> I would speculate that one problem with a diesel hybrid would be the
> extra power needed to crank the engine, remembering that this will
> happen quite frequently in a hybrid. This may mean more batteries
> (and hence weight) and a heavier engine anyway, meaning that the
> engine will need to run more frequently than it would in a petrol
> powered hybrid.
Does the hybrid engine actually stop and restart then? I had always
assumed that it simply dropped to a tick over when not required. Having to
restart each time must be horrendous.
--
Keith Willcocks
(If you can't laugh at life, it ain't worth living!)
Posted by Bill on May 4, 2006, 4:40 pm
> Does the hybrid engine actually stop and restart then? I had always
> assumed that it simply dropped to a tick over when not required. Having
> to restart each time must be horrendous.
> --
Yep. On rare occasions mine shudders slightly when shutting down but
otherwise it's not noticeable. A common hybrid experience is sitting at a
light listening to the folks around you wasting fuel for no good reason. I
corrected the subject line.
Posted by Keith Willcocks on May 4, 2006, 5:24 pm
>> Does the hybrid engine actually stop and restart then? I had always
>> assumed that it simply dropped to a tick over when not required. Having
>> to restart each time must be horrendous.
>> --
> Yep. On rare occasions mine shudders slightly when shutting down but
> otherwise it's not noticeable. A common hybrid experience is sitting at a
> light listening to the folks around you wasting fuel for no good reason.
> I corrected the subject line.
Actually, my Peugeot 406 HDI diesel (the common rail engine) averages 46mpg
. This means that, to average 46, it must at times exceed 50 to counteract
higher consumption in traffic. Bear in mind though that these averages are
using the Imperial gallon, not the smaller US one. Factoring the US
gallon into my spreadsheet shows an average of 35mpg(US). I assume that
the figures quoted for the hybrid are US, not Imperial?
--
Keith Willcocks
(If you can't laugh at life, it ain't worth living!)
>> Michael Pardee wrote:
>> <snip>
>>
>> Commonrail diesels are VERY good. Comparable power and better torque
>> than all but the top end petrol model-mates. They drive less like a
>> diesel than old TDs and get HUGE economy. Theyre quiet, not quite as
>> quiet as a petrol I admit, but certainly quieter than an older petrol
>> engine. This is why ive never seen the point of hybrid as a current
>> choice of car, maybe in 10 years when theyve matured.
>>
>> J
>>
> Hybrids work at the other end of the driving spectrum. The only advantage
> they offer on the open road (where diesels shine) is the ability to reduce
> engine size while maintaining passing performance, but in town they reduce
> the amount of time a gas or diesel engine is run in the lowest efficiency
> ranges. Hybridizing with a turbo diesel power plant is a very attractive
> idea - each covering the weaknesses of the other. There is no reason a TD
> hybrid 5 passenger sedan couldn't offer more than 100 mpg in town and 80
> mpg on the freeway, at least at 65 mph. Mainly it takes advances in the
> power electronics.
> Mike