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I’ve been working on a project for an engine manufacturer that involves propane injection. Basically, it’s just a matter of pre-heating the propane in order to make it more efficient.

I know propane injection has been around for years. I can’t say I’ve ever heard of it being pre-heated.

All the LP gas systems I used to maintain for a concrete trucking company used heat exchangers so enough of the gas could be vaporized to run full-sized engines. The only ones that would run directly off vapor from a Propane tank were very small 4 cylinders used for pumps, welders, etc. The liquid was run through a heater to vaporize it before going to the throttle body. The cars and pickups the company owned had to be fully warmed up before we hit the road so they would run somewhere near right. Of course, engines running on LP gas had only about 85% of the horsepower they did on gasoline due to some of the air through the carburetor being displaced by the fuel. Injecting liquid Propane into the manifold ports near the cylinder head is supposed to correct some of that problem.
Jerry

I don’t the specifics of what we’re doing. I’m not the engineer, I’m just the install guy.
It makes perfect sense to put some heat to LP. If you’ve ever tried to start a fork truck when it’s 0 degrees out, you’ll know why.

We’re actually heating it on the supply line side before it gets to the motor.

They’re blending LP with Natural gas too. Not for sure if it’s for emmissions, power, alternative fuel or what.

It’s quite interesting though.

"LP" is actually a mixture of Propane and Butane. Butane has more BTU's than the Propane, but it also "freezes" (stays liquid) at 32 degrees F. The Propane vaporizes at something like -70 degrees F. so more of it is mixed into the gas blend in the winter when it's needed for getting the vaporization process started. Once the engine begins to run and the coolant warms up, the heat exchanger can start vaporizing the Butane to take advantage of the extra power available by turning it into a gas that can be mixed with air for the right power output.
Jerry

Propane can be carried in a bucket at about -40F. Above that temperature, it starts to boil (vaporize) at atmospheric pressure, but on engine applications, a vaporizer, sometimes heated by the coolant system is typically used to get enough vapor to run the engine. Liquified fuel is usually delivered to the vaporizer on the engine. We've worked with LP fueled generators for remote communications sites and in order to get enough LP from the tanks to the engines, had to go with liquid draw from the tanks and vaporizers on the engines. Temperature dictated that approach even to get enough fuel thru the pipeline Even making the pipe 6 inches diameter wouldn't have delivered enough gas, because there wasn't enough heat available to vaporize it at the tanks. These were only 12kw gensets also.
Natural gas (mostly methane) has slightly more energy density (power) than gasoline and propane has just a touch more, but the problem is getting that energy to the engine. Gas (vapor) weighs a lot less than liquid fuel.