small heated amonia cooling

[wtarasen]

I am looking to help a friend who is a Corvette collector, mid 50's to mid 60's. He is having a problem with vapor lock in the fuel injection system due to the lower vaporization point of the unleaded fuels used today. We have installed an air blower which blows on the spider and an insulation barrier (some had this item stock) underneath to limit heat flow from the intake engine cover. However this is not sufficient.

In reviewing the layout of the car, on the right side of the right frame member the gas line is attached, and there is a c.a. 4" high space, 8" wide, and at least 18 inches long.

I was thinking of using the exhaust pipe as a heat source which is right on the other side of the frame member, bringing the gas accross the expanding it in a container to cool the fuel as it passes through.

Any experiences or comments would be greatly appreciated.

Regards

Bill

[monkey spanners]

I have heard that increasing the fuel pressure is effective in combating vapourisation, you raise the fuel line above the boiling point of the fuel.

A small ammonia refrigeration system would be very complicated to set up in an engine bay.

[wtarasen]

Please understand we are talking about an area underneath the passenger seating area, where the frame extends from the rear.

An additional requirement not previously noted, as these are collectables, there is to be no drilling or defamation of any of the original shape, form, material in anyway, form or fashion.

Further, these are mechanical injection units which are controled by the pressure of the secondary fuel pump. Any alteration thereof would impact the fuel spray amount and certainly the fuel economy.

Understand we are talking about 50's technology. My first thought was to do the reverse, i.e. put a small drain on the spider to flow fuel through the system. Unfortuneately, other than a full redesign of the system by having a bleed to flow fuel through and compensating by having a higher pressure pump, and then by have a sensor to moderate the pressure, well, the originality is gone, something not allowable for a spec original car. That's why if you watch Mecam car auctions on TV, cars which appear similar will sell for HUGELY different prices. No one wants a make over.

As an aside, his most valuable car is one which is in fairly terrible condition. But it is totally documented to be 100% original, paint and all. Try and purchase one of those. They simply don't exist in any numbers more than your fingers.

So what we are trying to do is install simple fixes, so the car is drivable in So Cal summer heat so he can enjoy the convertable without making any defects to the car. So all additions are made using existing mounting bolts, holes, etc. or straps.

My previously referenced indulstion is made by attaching it to the gaskets from the manifold to the head. The air blower used existing holes to mount, and did not in any way conflict with any existing hardware, distort anything. etc. Drilling something might subtract $100K from the value of the car. Who knows?

Certainly a challenging situation.

Thanks for the reply, hope you can think of something more applicable to the situation.

Regards

Bill

[Brian_UK]

If allowed in the car regs, can you accommodate a small 12v compressor (refrigerator size), a condenser coil under the car?

Evaporator could be copper tube surrounding the fuel lines.

http://www.rparts.com/Catalog/Major_...ss/danfoss.asp

[lowtempman]

Seems like ANYTHING you do will negate the originality of the car. Why not search for low octane gas, the kind sold when the car was new??? [ Expansion of exhaust gas will not cool down enough to help you anyway.]

Comment #2. Before operating the car, wrap ice around the gas tank.

Comment #3. Move to Alaska and only run the car in winter.

[wtarasen]

You got it lowtempman. NO alterations are allowed. That is largely what makes it a challenge. On the other hand, they are willing to pay dearly for a solution. And there are a few thousands of these out there with the same problem. And these guys all know each other as they trade expertise, parts, etc.

While I was there on last Sat AM, three other guys came over, all FI Vette owners, all having the same problem, all very original and collectable cars.

And to Brian-UK, thanks for the link. If we decide to go with a compressor unit and can find an alternative location for one, these appear to be right sized. However, the radiator is very flimsy and could not be undercar mounted, at least it would work until the first pebble came along. I am not too concerned about water/corrosion as these cars aren't driven in the rain in any event.

Regards

Bill

[lowtempman]

A more serious reply this time.. Check into thermoelectric refrigeration. I don't know much about it but do know that an electric current applied to a certain type of engineered material can be made to generate a cold surface that could potentially be used to cool the fuel line. York Refrigeration developed this long ago but could never establish a commercially viable product. I think specialty houses may still offer this device.

[Brian_UK]

^^Fair idea LTM, Peltier cooling could work.

[Magoo]

Here you can additives to put in fuel tank for older period cars.

[wtarasen]

Hey all, just to keep you informed. I did find a solution to the issue. I used thermoelectric plates, with a heat exchanger on the cold side to run the fuel through, and a finned heat sink on the other to dissipate the heat. The heat exchanger was somewhat smaller than the thermoelectric device so we could radiator hose clamp the whole device to the frame.

The heat exchanger came with 1/4 npt connections so we were able to connect it right into the fuel line (sorry, we did remove the original fuel line and install one we cut.).

The heat sink was screwed into the sides of the heat exchanger providing adequate pressure to insure heat transfer.

SO!!, no car alterations. No visibal things in the engine compartment. Two wires running behind the firewall, drawing 9 amps.

Regards

Bill

[lowtempman]

Hey all, just to keep you informed. I did find a solution to the issue. I used thermoelectric plates, with a heat exchanger on the cold side to run the fuel through, and a finned heat sink on the other to dissipate the heat. The heat exchanger was somewhat smaller than the thermoelectric device so we could radiator hose clamp the whole device to the frame.

The heat exchanger came with 1/4 npt connections so we were able to connect it right into the fuel line (sorry, we did remove the original fuel line and install one we cut.).

The heat sink was screwed into the sides of the heat exchanger providing adequate pressure to insure heat transfer.

SO!!, no car alterations. No visibal things in the engine compartment. Two wires running behind the firewall, drawing 9 amps.

Regards

Bill

Hello, Bill,
Glad to hear your Thermoelectric solution worked OK. Have you found that it works OK even at high car speeds? [ Higher fuel flow, higher pressure drop, less cooling rate, more apt to flash] Just curious.

[nerissa22]

heated amonia cooling has good content in post...

[wtarasen]

I want to thank you for your advice. I looked into thermoelectrics and designed a small package that could be radiator clamped to the right frame under the car, with fittings that would couple the fuel line into the heat exchanger. We measured 10 C cooling at a flow of 4 gal per hour. Of course where the flow is lower and the problem mainly occurs, in city traffic, the cooling will be increased.

We will await the final test next summer.

Thanks again.

Regards

Bill