The rub is that they aren't CI after the retrofit but still diesel engines. Go figure... And naturally fumigation like you mentioned, although depending on the app the amount of diesel needed can relatively small since there's only a small amount injected to kick off combustion.

How in the world can you call something a diesel if it doesn't use CI? I assume from that, these conversions you refer to use SI like any standard Propane converted gasoline engine? If they still have a diesel level of compression the Propane being high octane will give them better milage than a low octane gasoline engine would.

Any links?, this offshoot is new territory for me.

It's one of the regulatory/semantic deals based on what I've read. Something that's still technically a diesel engine, even though it's been converted to natural gas. I dunno why offhand but maybe it's the same reason why drivers in CA or other states w/ smog would drop a gasoline engine in a vehicle registered as a diesel.

I imagine that a lower compression diesel could have to glow plugs removed/spark plugs installed, a mesh/block heater installed for startup, and a TBI installed w/ a second tank for something high octane (E100/etc), and be a SI/CI engine since the owner can switch over on demand.

Edit- nvm about the otto cycle part.

Westport Technologies partners with Cummins and some other diesel engines to use compressed natural gas. This explains the application for heavy duty diesel applications. See Westport- Direct Injection

Technology Description
High Pressure Direct Injection relies on late-cycle high-pressure injection of a gaseous fuel, such as natural gas, into a combustion chamber of an internal combustion engine. The natural gas is injected at the end of the compression stroke, just like the diesel fuel is injected at the end of the compression stroke in a diesel engine. Under the pressures found in the combustion chamber of a normal diesel engine, natural gas requires higher ignition temperature than diesel (circa 800° C vs. 500° C) to maintain acceptable ignition delay period of less than 1 millisecond. To assist with the ignition of natural gas, a small amount of diesel fuel is injected into the engine cylinder using the same injector followed by the main natural gas fuel injection. This diesel fuel acts as a pilot or “liquid spark plug” which ignites rapidly the hot combustion products then igniting the natural gas.

HPDI allows diesel-cycle operation with over 90% replacement of diesel fuel. Compared to other natural gas engines, because of Westport's direct injection approach, HPDI also eliminates both part-load throttling and limits on torque due to the onset of knock. Diesel pilot-ignition has two distinct advantages: durability and ignition quality. Diesel injection systems are inherently durable as demonstrated by conventional experience. In addition, multiple ignition sites can be easily arranged (close to one per gas jet).

Sorry, but 40-45 MPG on the highway is still far more impressive than 30. None of that matters, though. What's yer city mileage?

Anyways, is your car still worth 80% of sticker, even at 2.5 years old and with 50,000 miles on the odo? (anecdotal evidence suggests dealer offers near 90-100% of new MSRP value)

THAT, my friend, is the value of a 40+ MPG German sedan.

kbb

Sorry, I was rather abrupt if not outright rude. Where did the extra cost come from? Did they do work without asking? Did they lie about the cost? Seems like you should have some recourse.

I'm sure T. Boone Pickens appreciates these guys.

Yes, I've driven modern diesel passenger cars as well.



All of our propane delivery trucks including our tank/service body trucks are diesels.