Gas-diesel RE Buickanddeere and Sprint 6

On the subject of the various comments about "diesels" running on gasoline. If I have this correct, Mr. Buickanddeere say they exist and Mr. Sprint 6 says they do not.

General Motors was working on such a thing until they went bankrupt.

Mazda says their new compression-ignition powered car that runs on gasoline is coming out this September.
Kind of interested to read about it. Not that I want one. That said, it certainly DOES exist.

I have no idea what became of the one GM was working on. I think GM is too busy making stupid commercials trashing Ford.

Mazda has opened orders in Europe for its new-generation Mazda3 compact car equipped with its fuel-saving Skyactiv-X powertrain.

The Mazda Skyactiv-X has a gasoline engine with spark plug controlled compression Ignition (SPCCI) technology. Mazda says this is the first commercial gasoline unit to combine the spark ignition of a gasoline engine with the compression ignition of a diesel.

According to Mazda, the Skyactiv-X engine provides drivers with the free-revving performance of a gasoline engine and the superior response of a diesel, plus a reduction in fuel consumption and CO2 emissions.

The first deliveries in Europe for Mazda3 cars with Skyactiv-X are scheduled for September.

International and others had engines that started on gas then ran on diesel .

I didn't say compression ignition gas engines don't exist, just that current production GDI engines are not compression ignited. I should have been clearer. The discussion was about commercially available engines. Theoretical and developmental things are always out there, but may never see the light of day. There was at least one 454 built that used direct injection gasoline and had an open intake, the intake valve lift was varied, and fuel amount metered to control engine speed. It supposedly got 4.3 V6 fuel economy.

Allis Chalmers had a diesel that used spark plugs

The AC so-called "oil engines" were not true diesels but they did have spark ignition and did not burn gasoline.

Dean

Anyone remember the Waukesha-Hesselman diesel? It had an inline pump, injectors and spark plugs. Far as pickups go if you really need the power and torque diesel will do the job easier than gas will. All depends on what is really needed. Lots of guys with diesel could do fine with gas too IF they are honest with themselves..

A lot of things have to be overcome to make a truck engine compression ignition. Right now, GM can't keep pistons together in the 1.4 Turbo engines due to pre-ignition. Compression ignition, while feasible, will require quality parts that manufacturers don't want to spend money on.

I said it runs in diesel mode most of the time. At startup and idle the fuel is injected and the spark plug ignites the mixture
. At higher rpms and under load when the combustion chamber pressure is higher due to the higher mechanical compression ratio , increased combustion chamber fill and combustion chamber temps are hotter . The gasoline burns as soon as it atomizes and mixes with air in the combustion chamber due to heat from compression.

Even if such an engine exists (diesel/gasoline, yep I know that's a different vehicle and different use) having been in the trucking business and gaining experience, if I were to purchase a diesel pickup you can bet for sure it would have an inline 6 cylinder Cummins engine...???..NOT any V8. Still each are entitled to their own preferences and opinions and have had different experiences I'm sure, so to each their own, its their money and their choice...??..

John T

No it doesn't, that would be pre-ignition.
The improved atomization allows for
increased detonation resistance before the
spark plug sets it off. No current US
commercially available GDI engine is
compression ignited. I have been around
GDI engines since my first GM training on
the subject in 2007, proir to the 3600
going direct inject in the Acadia and
Enclave for the '09 model year.

(quoted from post at 12:39:54 06/14/19) No it doesn't, that would be pre-ignition.
The improved atomization allows for
increased detonation resistance before the
spark plug sets it off. No current US
commercially available GDI engine is
compression ignited. I have been around
GDI engines since my first GM training on
the subject in 2007, proir to the 3600
going direct inject in the Acadia and
Enclave for the '09 model year.

Click to expand...

Alright then, I was mistaken .

Hey Glen, I bet that's the first time for today right lol. Yours truly and allllllllllllllll others here have done the same I'm sure...??...There's NO infallibity on this site I've seen in around 28 years and opinions flow freely. What's great now is many questions asked can be researched on Google !!!!!!!!!!!!!

Take care now

John T

After reading some of the responses, it seems a few people confuse an engine that can run on diesel fuel, versus an engine that uses the so-called "diesel" compression-ignition system. Not sure why Rudolph Diesel gets the credit, but it is what it is.

Plenty of old cars, tractors and even a few chainsaws that run on diesel fuel but are either hot-bulb or spark ignition. I have a "diesel" chainsaw in my collection. Kind of a useless boat-anchor but kind of interesting.

Had a G JD we pushed the envelope on compression one time. Ran like a 720 diesel and when we tried to shut it off it wouldn't quit, just kept on dieseling. Had to block the air intake to shut it down.

I believe Mazda took the Wankel rotary engine a lot further than GM did. I had friends that had one in a Station Wagon.

A compression ignition engine (aka Diesel cycle) can run on any liquid fuel. The limitation is the injection equipment needs to be able to handle the fuel being used. If you want to be able to run gas in a compression ignition engine, the injection pump needs to be able to handle the dryness of the fuel. And yes the timing will need to be retarded some. Pre ignition is only an issue if the fuel is injected too far in advance of TDC. Modern Diesel engines actually do this on purpose, pilot injection serves to increase the heat in the cylinder with a small shot of fuel way ahead of TDC. The main dose of fuel still comes just before TDC to give the fuel a chance to light and start burning just as the piston heads back down.

(quoted from post at 06:17:25 06/15/19) A compression ignition engine (aka Diesel cycle) can run on any liquid fuel. The limitation is the injection equipment needs to be able to handle the fuel being used. If you want to be able to run gas in a compression ignition engine, the injection pump needs to be able to handle the dryness of the fuel. And yes the timing will need to be retarded some. Pre ignition is only an issue if the fuel is injected too far in advance of TDC. Modern Diesel engines actually do this on purpose, pilot injection serves to increase the heat in the cylinder with a small shot of fuel way ahead of TDC. The main dose of fuel still comes just before TDC to give the fuel a chance to light and start burning just as the piston heads back down.

Click to expand...

Pilot injection for idle and puttering around . At full power engineers use intercooling, EGR and retarded injection timing to limit max combustion chamber temperature . In order to reduce the amount of NOX formed .

By injecting the gasoline late in the compression stroke. This by default reduces the duration of time that the fuel will have an opportunity to auto ignite.
The very high turbulence does breakup flame fronts and pressure waves if they occur prior to ignition spark .
I would still wager at full rpm and full power that GDI engines are not totally dependent on the spark plug for ignition .