Compression Ignition Gasoline Direct Injection

[Shannow]

Spark and Diesel engines are getting closer and closer with new designs...

Was messing around looking at the piston land cracking issues that some small high boost direct injection engines have, potentially related to oil chemistry/leakage...Low Speed Pre-Ignition in direct injection engines, and came across a couple of papers/precis on gasoline compression ignition engines.

http://delphi.com/pdf/techpapers/2013-01-0272.pdf

Quote:
Part-Load Operation of Gasoline Direct-Injection
Compression Ignition (GDCI) Engine


and precis

http://papers.sae.org/2013-01-2699/
Quote:
Investigation of Lubrication Oil as an Ignition Source in Dual Fuel Combustion Engin


Discussed a little back in 2007
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=972867

 

[SteveSRT8]

with many new ideas popping up it is an exciting time, engines may make a huge leap forward in power and economy if this is perfected for a production vehicle...

 

[cchase]

Wonder what the advantage of a compression ignition gasoline engine would be? Lower BTU's than diesel anyway.

 

[skyactiv]

Originally Posted By: cchase
Wonder what the advantage of a compression ignition gasoline engine would be? Lower BTU's than diesel anyway.


The manufacturing cost of a gasoline compression engine vs a diesel could be lower in the long run.

It would take an act of G-- to get the majority of Americans to accept diesel.

Diesel vehicles are a niche market and the manufactures charge a fortune for the option. $8315 for an F250, the Cruze and VW's are costly, too.

 

[cchase]

I doubt manufacturing costs would be lower for a compression ignition gas engine compared to a diesel since most of the additional cost in a diesel engine is not for running diesel but handling compression ignition. But I admit, it's all speculation.

 

[OneEyeJack]

If you park your diesel powered car in the garage with your clothes hamper, washer and dryer soon people you meet socially will guess that you drive a diesel.

 

[JHZR2]

Originally Posted By: cchase
Wonder what the advantage of a compression ignition gasoline engine would be? Lower BTU's than diesel anyway.


That was always the argument for diesel, but in reality its what? 2%?

 

[Shannow]

Originally Posted By: cchase
Wonder what the advantage of a compression ignition gasoline engine would be? Lower BTU's than diesel anyway.


Figure 6...7-8% better BSFC (in terms of fuel mass) than diesel, which has 13% more mass per gallon.

So it splits the gap, between spark ignition and diesel, at lower pressure operation which can utilise more SI oriented architecture.

Low NOx, no diesel clatter.

 

[cchase]

Why wouldn't it have diesel clatter?

 

[Shannow]

They give a hint in the paper...

the clatter in diesels is due to the fact that the fuel has to evaporate and mix to the point that there's enough around stoichiometric for combustion to start...and when it does, it geos off with a bang...Peugeot have up to 7 individual injections in a single firing stroke to try control it.

 

[camelCase]

Originally Posted By: Shannow
They give a hint in the paper...

the clatter in diesels is due to the fact that the fuel has to evaporate and mix to the point that there's enough around stoichiometric for combustion to start...and when it does, it geos off with a bang...Peugeot have up to 7 individual injections in a single firing stroke to try control it.




The HCCI diesels are trying to get rid of that. Ford is doing a lot of development with them. Essentially, they inject a small "starter" amount of fuel, then inject the fuel charge after it starts to combust.


We will see diesels lower compression ratios, while gasoline engines continue to raise them. The designs of diesels have a lot of "baked in" goodies that improve fuel economy - like not needing a throttle. Compression ignited gasoline engines will give us a lot of benefits in both power and economy (think about the torque that diesels make).

I wish I had my ICE engineering design book on hand so I could screen shot some pages.

 

[Claud]

Originally Posted By: skyactiv

Wonder what the advantage of a compression ignition gasoline engine would be? Lower BTU's than diesel anyway.


The manufacturing cost of a gasoline compression engine vs a diesel could be lower in the long run.

It would take an act of G-- to get the majority of Americans to accept diesel.

Diesel vehicles are a niche market and the manufactures charge a fortune for the option. $8315 for an F250, the Cruze and VW's are costly, too.

North America and Europe are almost on different planets regarding diesel engines.
In most of western Europe (I don't know about former Warsaw pact nations) diesel engine cars outsell gasoline models by vehicle volume.
A consequence of this is the premium for diesel power has almost disappeared, indeed in some cases diesel versions are cheaper than gasoline ones. Also diesel fuel is significantly cheaper than gas in France, Germany and the low countries. In the UK diesel is slightly more expensive than gas.

And modern diesel engines have advanced light years from the smokey, lethargic, smelly taxi pack specials current when Oldsmobile launched its ill fated diesel 350.
My wifes Peugeot 307 taxi cab is a fine example, cold starting is almost instantaneous, noise levels are not much greater than equivalent gasoline cars, performance is brisk, and cruising at 70+ mph with a full load effortless, and it returns 42 mpg (imperial).
It's fair to say it's noisier than gas models, but not by much, and the fumes are a bit smelly, but you would have to stand by the exhaust tailpipe for a while to get smelly clothes.

I think some of the reasons diesel hasn't found favour in North America are;
Gas is still cheap. Ok I know it has increased in price hugely over the last 10 years or so, but it is still 30-40% of the price in Europe.
People still have memories of the terrible Oldsmobile diesel of the late '70s-early '80s.
Diesels don't go well with automatic transmissions, although lately this has improved greatly.
Particulate emissions have been a problem too, again big advances have been made in recent years.
Diesels are less tolerant of neglected lubrication maintenance than gas vehicles.
There isn't an infrastructure of shops with trained technicians to look after mainstream cars. A classic catch-22 situation, no cars sold because there is nowhere to take them for service, no point in setting up a diesel repair shop if there are no cars to service and repair.


Claud.

 

[Hyde244]

Mazda appears to be moving into this technology as the next step of their Skyactiv engines.

http://oppositelock.jalopnik.com/mazdas-saving-dino-juice-engines-by-going-beyond-petro-1549648428/@ballaban?utm_campaign=socialflow_jalopnik_facebook&utm_source=jalopnik_facebook&utm_medium=socialflow

 

[Wilhelm_D]

Originally Posted By: cchase
Wonder what the advantage of a compression ignition gasoline engine would be?

Increased efficiency due to a higher compression ratio and reduction of pumping losses, the elimination of costly components such as high-pressure fuel pumps, particulate filters, and urea-injection systems are all goals.

The Delphi-Hyundai CD gasoline engine uses conventional solenoid injectors instead of piezo units, and Hyundai says it is running fuel pressures of less than 500 bar compared to a diesel unit’s 1800–2000-bar.

 

[Wilhelm_D]

Originally Posted By: Claud
I think some of the reasons diesel hasn't found favour in North America are;
Gas is still cheap. Ok I know it has increased in price hugely over the last 10 years or so, but it is still 30-40% of the price in Europe.

It might be more accurate to say that motor fuels are cheap in North America, but gasoline is even cheaper than diesel.

That really has to do with the fact that our refineries are aimed at gasoline production and that since most diesels are commercial trucks rather than passenger cars the tax structures reflect it.

 

[ironman_gq]

Originally Posted By: camelCase
Originally Posted By: Shannow
They give a hint in the paper...

the clatter in diesels is due to the fact that the fuel has to evaporate and mix to the point that there's enough around stoichiometric for combustion to start...and when it does, it geos off with a bang...Peugeot have up to 7 individual injections in a single firing stroke to try control it.




The HCCI diesels are trying to get rid of that. Ford is doing a lot of development with them. Essentially, they inject a small "starter" amount of fuel, then inject the fuel charge after it starts to combust.


We will see diesels lower compression ratios, while gasoline engines continue to raise them. The designs of diesels have a lot of "baked in" goodies that improve fuel economy - like not needing a throttle. Compression ignited gasoline engines will give us a lot of benefits in both power and economy (think about the torque that diesels make).

I wish I had my ICE engineering design book on hand so I could screen shot some pages.


They've been using pilot injection for over a decade on diesels in pickups to make them quieter. I've seen guys tuning duramax trucks turn off the pilot injection and there is a large difference in the amount of sound they make, with it off they go right back to the typical clatter box that diesels are known for, turn the pilot injection back on and they quiet right down.