Turbo Diesel instant boost
Turbo Diesel instant boost
(OP)
Just an idea I conjured up recently. Naturally aspirated Diesels draw basically the same amount of air at idle as they do at full revs, They only vary the amount of fuel injected into the cylinder to vary their output, add more air (i.e turbo) and you're able to burn more fuel - more power...But with turbo lag still posing an engineer's nightmare. Variable vane turbo's, while better, still aren't perfect. What aboutfitting an injector situated between the exhaust manifold and the turbocharger. This would allow full boost to be achieved from idle - actuated with application of full throttle. NO turbo lag, Super charger style boost without the parasitic drag... Just a thought?





RE: Turbo Diesel instant boost
Dumping xtra fuel at the turbo wont make it spin faster, more than likely it will start a fire....
To get the effect you are after, a well set up NOS system that actuates at part trottle and low boost would do the job -not pointed at the exhaust-, till the bottle ran out...
RE: Turbo Diesel instant boost
The train of thought was to optimise thermal efficiency and drivablity of Diesel.
Possible to substitute fuel for steam injection at nozzle and utilise huge expansion rate of water to afford similar results??? Just thinking outside the square... More of a why not than a why.
RE: Turbo Diesel instant boost
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: Turbo Diesel instant boost
RE: Turbo Diesel instant boost
A compound turbo/Roots blower type system will solve both problems if set up properly.
Regards
eng-tips, by professional engineers for professional engineers
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RE: Turbo Diesel instant boost
Sorry, but could you explain that one?
Bill
RE: Turbo Diesel instant boost
RE: Turbo Diesel instant boost
RE: Turbo Diesel instant boost
Yes, I can see no difference in air flow between full-speed/full load and full-speed/no load, I just thought I'd ask gizmag1 the question.
I suppose it's me being thick.
Bill
RE: Turbo Diesel instant boost
There are also a few electrically enhanced turbos and air pumps for that very purpose.
RE: Turbo Diesel instant boost
Electric supercharging
http:
Bill
RE: Turbo Diesel instant boost
The turbine extracts thermal and kinetic energy from the exhaust gases. If you add water, then energy is required to evaporate the water, and this comes from reducing the energy in the gases before the turbine. If steam is added then you partly have a steam turbine. So while using enough steam should provide power to the turbine, it begs the question what is the power source for this partly steam turbine?
RE: Turbo Diesel instant boost
RE: Turbo Diesel instant boost
RE: Turbo Diesel instant boost
I think everyone who actually belongs here understands constant a:f ratio and air throttle of SI engines vs fuel metered WOT of CI engine, in fact many actually design engines for a living.
You still overlook your mistake in your original post even though several have pointed it out.
A diesel does not ingest the same amount of air at idle as at full speed. It only ingests the same amount of air at constant rpm. If idle is 500 rpm and full speed is 2500 rpm, at full speed it ingests about 5 times as much air. A diesel does ingest about the same amount of air per turn of the engine whether at full load or light load.
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Turbo Diesel instant boost
RE: Turbo Diesel instant boost
Bill
RE: Turbo Diesel instant boost
As previously mentioned a diesel runs without air throttling as in the case of SI engines and hence runs at full compression. I would hasten to add there are some systems that do use a throttle butterfly to control fueling.
RE: Turbo Diesel instant boost
Hello r2800. I thought that any air throttling on a diesel for fueling control was now quite archaic. I remember seeing something like this in my first college thermodynamics book in the 60s and it was old even then.
Any experience I've had with throttle plates in diesels has been as part of an emissions control (EGR/crankcase gas) and/or 'shut off shake' control system.
gizmag1 - although r2800 says that volumetric efficiency tends to be (broadly) constant over a range of engine speeds, speed is obviously the ultimate control on air consumption, as you have acknowledged in your last post.
Bill
RE: Turbo Diesel instant boost
RE: Turbo Diesel instant boost
RE: Turbo Diesel instant boost
A 'Dual-Turbo' (sequential-turbo):
http://www
(The porsche 959 originally introduced this concept).
Or a mechanical supercharger that is engaged at low rpms:
http://www
Or a pressure wave supercharger:
htt
http://www.wenko.ch/e/news.e/techinfocontent.e.jsp
Mazda 626 was running it.
RE: Turbo Diesel instant boost
r2800 - Like SomptingGuy, I'd be very interested to have any links you may have for the Toyota application.
Bill
RE: Turbo Diesel instant boost
See my post of a few days ago.
gizmag1
There is an extensive previous thread on compound supercharging or twin-charging. The on site google feature works best.
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Turbo Diesel instant boost
Relative to your original post (this thread has really meandered), and to GregLocock's answer, please do a search for the French built SACM Hyperbar diesel engine that is used in the Leclerc main battle tank.
Dick Vincent
RE: Turbo Diesel instant boost
RE: Turbo Diesel instant boost
In my earlier life I worked extensively on trucks & coaches and pnuematic governors were common as indeed was a throttle set up to allow manifold vacuum to be built up for servo brake operation, I'm thinking of old landrover diesels here.
RE: Turbo Diesel instant boost
Exactly what has been said. The 'throttle' is used so that, under certain speed/load conditions, EGR and crank case gas is consumed in preference to clean air to help control emissions. The valve is often shut at key-off to help reduce engine shake as it stops.
Well, I suppose the adoption of vacuum pumps to power the brakes and the efficiency loss due to throttled operation killed off the old pneumatic type governeors. I certainly never saw one on the 30 years I've been associated with truck and car diesels.
Bill
RE: Turbo Diesel instant boost
Ford Trader 4 & 6 cyl models, Some Perkins models too.
Admittedly these are late 50's early 60s.
RE: Turbo Diesel instant boost
I've seen throttle bodies on the old British diesels as others have mentioned,and diaphram govenors.The last vacuum govenors I worked on were in the Nissan 220D,a common vehicle for taxi's.
RE: Turbo Diesel instant boost
http://www.rallycars.com/Cars/bangbang.html
It's incredibly loud and will never make it to production vehicles in that form.
RE: Turbo Diesel instant boost
(TSD Rally driver, RA Worker, Service crew chief #734, KD8EUT)
RE: Turbo Diesel instant boost
RE: Turbo Diesel instant boost
Of course we have our share of disagreements here, though they usually can be solved with a small application of math and science, something that normally doesnt help at NABISCO.
RE: Turbo Diesel instant boost