Would this gasoline engine to diesel conversion work?

Question

Fuel injected gasoline engines cannot burn diesel fuel because of several reasons.

GASOLINE ENGINE
Computer injected, spark ignited, Low torque: total ignition at or before TDC

DIESEL ENGINE
Mechanical direct injection, Compression ignition, High torque: Prolonged diesel ignition during stroke

Solution to conversion

1)Injection system: Diesel injection pump, 2)Ignition system: Injection line heating to above autoignition, 3)High Torque: Modify injection pump to reduce injection duration at all speeds

Ok, so how can we do this?

Replace spark plugs with diesel injectors, and remove gasoline fuel injectors. Install pulley driven diesel fuel injection pump on the engine and connect fuel lines to the injectors.

So, the fuel will be delivered to each cylinder at TDC as the pump rotates.

How to ignite it?

Heat each injector line to above autoignition temperature with an electric cable heater wrapped around it. This allows cold, low compression air to ignite with fuel already at autoignition temperature. High compression air is not needed.

Now that you are setup how can you make the system create less torque so you don't destroy that gasoline engine block?

Gasoline engines cannot handle the torque levels of a diesel, they wear out very quickly. The source of diesel torque is not the fuel, but the prolonged injection of diesel throughout the power stroke.

Modify a diesel injection pump to a short injection pulse while at slow speed. This normally only happens when the pump is at high speed. If the fuel is injected very quickly rather than in an extended injection down the power stroke, torque will drop. All the while maintaining precise timing of injection and power of the engine.

You could just use a bigger injection pump pulley, but timing of injection will be off.



Now some possible feasibility conditions:

1) heated fuel results in coked(clogged) injector 2) Injector loses lubricity and wears out due to loss of viscosity due to fuel heating 3) Fuel line connection failure due to heat 4) Injection duration is not short enough at low throttle on injection pump which results in engine damaging torque

I'm not looking for same efficiency. I'd convert to run on biodiesel, svo, wvo. Cost of diesel engine is high. Plus labor.

Problem: Fuel air swirl and mix in ignition delay before TDC would be the problem. Fuel vaporization time would decrease as fuel is heated way above flash and autoignition temp could help with fuel air mixing.

Answer 1

General motors converted some 350 V-8's to run on diesel back in the late 1970's-1980's. I had a friend who had a Buick or Olds station wagon that was so equipped. You might try some research into that. As I remember, the engine was very problematic.

But at least I can vouch for the fact that it can and has been done. If you can find out what GM did it may be of some help to you. You may find some old shop manuals.

.

Answer 2

Heating the fuel will not get the ignition you are looking for. Modern diesel engines run a compressions ratio of around 20:1 versus a gasoline engine of around 9:1. That is nearly double the pressure. A modern gasoline engine with an aluminum head could not handle these pressures.

Adapting an injection pump to belt driven would be troublesome, as the belt stretches, you would lose timing. A majority of injection pumps are gear or shaft driven directly off the cam gear.

To install injectors in a gasoline head would require very customized parts.

The internals of the gasoline engine would not withstand the direct injection, and combustion of the diesel fuel. You would most likely melt the piston, or bend/break connecting rods under the extreme pressures.

What you propose is possible but would cost tens of thousands of dollars in parts and labor, when you could have spent $5000 and bought a brand new diesel motor.

Save yourself the trouble, sell the gasser, and just buy a diesel out-right.

Answer 3

You are trying to reinvent the wheel. Consider the power required to heat the fuel to Autoignition now what happens when fluids under pressure are released, a shop air supply...a blow gun on a 90 degree plus day point the nozzle away from you and squeeze the trigger the temp of the air comming out of the nozzle is as much as thirty degrees cooler. you cannot gaurantee ignition of a fuel in a spark ignited engine, hence O2 sensors and constant adjustment of the fuel air mix via clossed loop feer back... your barking at the wrong angle

Answer 4

i don't know why you would really want to do this, but if you did here is what else you got to do.

it would be much more like a diesel if you just get some custom pistons made with very high compression. this way you wouldn't have to preheat the fuel like your talking about.

i don't know how well the engine would take that much compression.

you would have to cut o ring groves in the block and heads and get o ringed head gaskets to handle that much compression.

you would also have to get some high strength connecting rods.

also it would be a good idea to strengthen the block with block filler. if you were really wanting to do this i would suggest researching ways that people strengthen blocks for racing.

i encourage you to try it and i would love to see how well it works. although it would probably be more cost effective to find a diesel and figure out a way to make it fit in your car. because to do this right it would probably cost a couple thousand dollars. my guess would be about $300-$500 for pistons, probably about $200 for rods, machining and block strengthening would probably be about $300.

Answer 5

This can not be accomplished with a gasoline engine because of the enormous difference in compression ratio.

A diesel engine requires upwards of 25 to 1 and more compression which the gasoline engine doesn't have.

Answer 6

Why would anyone want to go to the trouble and expense of converting a gas engine to diesel??
That's retarded...Nothing that is converted from one use to another is as efficient as one that is designed for such use. Take the a/c conversions on cars with an r12 system to r134a. It works, but not nearly as good as the systems designed for r134a. It doesn't make sense to convert gas to diesel because when the petroleum is gone there will be no more gas or diesel fuel.

Answer 7

First off . Why would you want to? How would you control your fuel timing on a belt driven system? What about the fact that most modern motors have aluminium heads and some have blocks made of aluminium as well. How would you handle that? why don`t you do it with a lawnmower motor and come back and see us

Answer 8

this is not possible as gas engines have other parts not used on diesels. one would be spark plugs. on a second note... with diesel being the most expensive fuel why even bother.

Answer 9

I think you would need to be concerned about the extra compression that would probably destroy an engine designed to run gasoline.

Answer 10

Omigod,did you post this for grins?.Go read a book on engine design. If you have some spare time could you find a cure for the common cold?