Posted by Ray O on May 4, 2006, 10:08 pm
> richard schumacher wrote:
>> No, it would be done the way the Prius does it: spin the engine up to
>> speed before applying compression (that is, hold the valves open) and
>> fuel.
> So it has valve lifters. Is the only reason this is not done on regular
> engines the extra complexity?
I recommend that you google "prius atkinson cycle" or just "atkinson cycle"
to get an idea of how the idea works. their description is much better than
what I'd come up with.
--
Ray O
(correct punctuation to reply)
Posted by OrionPax on May 23, 2006, 6:51 pm
@petezilla.co.uk:
> richard schumacher wrote:
>> No, it would be done the way the Prius does it: spin the engine up to
>> speed before applying compression (that is, hold the valves open) and
>> fuel.
>
> So it has valve lifters. Is the only reason this is not done on regular
> engines the extra complexity?
Regular engines don't have a "starter" that's strong enough to repeatedly
spin-up the engine. The MG1 in the Prius is not only a starter, but it's
also a generator, and part of the traction motors.
--
Joseph nugundam ===========/==\=IIGS=/==\=============/==\==============/==
\
# FreeBSD: The Power to Serve >> www.freebsd.org
Posted by kkerrison on May 25, 2006, 6:46 am
It turns out that GM of all people is way ahead in devloping hybrid
diesel - in buses. the following links tell the story - diesel, hybrid,
regenerative braking - the lot! 60% gain in economy.
www.shadetreemechanic.com/allison_hybrid_drive.htm
www.gm.com/company/gmability/edu_k-12/9-12/fc_energy/hybrid_allison.html
www.hybrid-vehicles.net/gm-allison-hybrid-bus.htm
I owe it to an Australian electronics magazine - Silicon Chip - which
is running an article in its June issue on this GM - Allison project
which is not pie in the sky - the vehicles are operating in various
parts of the US.
Posted by Lynn McGuire on May 4, 2006, 4:24 pm
>> 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.
> Would be harder than with a petrol - re-starting a diesel requires far more
cranking torque, so you'd need more powerful motors
> and its likely to cause a jerk, unlike a petrol car that can smoothly be
'bumped' as its low compression.
Nope. The VW diesel uses the same starter as the gasoline model,
about 3 hp. A 20 to 50 kw motor will easily spin the diesel motor.
Lynn
Posted by Bill on May 4, 2006, 12:56 am
> <snip)
>> Diesels are still cantankerous - cold starts are problematic; they still
>> clatter like something's wrong, especially when cold; the diesel guys who
>> gave me basic instruction warned me to take it easy on the engine until
>> it warmed up / quieted down.
> This was true of Turbo Diesels but I have found that the modern common
> rail diesel engine (of which I have Peugeots HDI model in the 406 that I
> had new in 1999) starts better than any petrol engine I have used and is
> far less noisy than its predecessors. Also, unlike petrol engines, there
> is no drop off in performance before the engine warms up, it starts and is
> ready to give full acceleration straight away.
> <snip>
>> Turbo diesels are plenty powerful once the turbo gets spun up, but until
>> then I wish I had four feet so I could hold the accelerator to the floor
>> with one, feather the clutch with a second, and do the Fred Flintstone
>> thing with the other two. You haven't experienced turbo lag until you've
>> waited for 20 psi boost to appear.
> Again, IME, the HDI engine seems not to suffer from any lag and is more
> akin to driving a petrol engined car when it comes to pull away and
> acceleration. And for interests sake my car averages 46mpg.
I get better mileage than that with my Prius, burn less expensive fuel, and
my exhaust emissions are cleaner. What's your point?
>> No, it would be done the way the Prius does it: spin the engine up to
>> speed before applying compression (that is, hold the valves open) and
>> fuel.
> So it has valve lifters. Is the only reason this is not done on regular
> engines the extra complexity?