Back, (quite a few years ago), when I worked for the Ford Motor Company as their "Boost Guy" on Research Projects, I did a design project for the SVO Boss. A guy named John Coletti.

He was interested in making one of his SVO Lightning Trucks unique.
So I asked some of the Visteon Engineers if they had a really good A/C Guy who could work with me on
designing a few cooling systems for our "Mule" Truck and eventually Colletti's "one off" truck.

So we looked at several A/C cooling systems. This was years before some of the other guys went down that A/C Cooling path. The systems we looked at were:

Method # 1: Direct A/C Intercooling:
In this method the intercooler uses R-134a from the a/c system to directly cool the
incoming charge from the boosting device. This method of cooling requires few additional
parts. The pressure capability of the parts must be increased over existing air to air
and water intercooler systems. The intercooling device must meet the airflow demand.
The benefits of this system are few parts and fast response time. There are several
drawbacks with this system. When the compressor is off, there is no charge air intercooling.
There is a limited reserve capacity. There is a potential f.e. penalty in normal driving.

Method # 2: Air to Air Intercooling + Direct A/C intercooling:
In this method the incoming charge is first cooled by an Air to Air Intercooler. The air
leaves the Air to Air Intercooler and enters the Direct A/C Intercooler. The majority of
the cooling takes place in the Air to Air Intercooler and therefore the work required by
the Direct A/C Intercooler on the A/C system is much lower. A few additional parts are
required. This system has a fast response time plus it will cool the incoming charge
when the a/c system is off. The pressure requirements are the same as Method # 1.
This method does not require the a/c system to be active to provide intercooling. The a/c
system can be activated during specified calibratable modes. There is a minimal f.e. penalty.

Method # 3: Water to Air Intercooling with A/C chilled Water reservoir
In this method the incoming charge is cooled by a Water to Air Intercooler. The air
leaves the boosting device, passes through the Water to Air Intercooler, and then enters
the engine. This method has two separate cooling loops with the common point being
an A/C to Water chiller enclosed in the water reservoir. Chilled water from the Water
Reservoir is pumped to the Water to Air Intercooler and back to the Water Reservoir.
R134a is pumped from the A/C Compressor, through the condenser, to the A/C to Water
chiller and back to the A/C Compressor. The response time is good. The system will cool
the incoming charge if the a/c system is off. The system allows "Thermal Inertia" storage
which increases the reserve capacity of the system. This method allows charging the
system under low load conditions and turning the a/c compressor off under high boost
conditions for additional power to the vehicle and improved fuel economy over Method # 1 or
Method # 2. One strategy would be to activate the a/c system under decel modes.
This would make use of energy not being utilized at the present time with a potential for low
f.e. penalty.

Further investigations into chilled intercooling will determine if this technology will allow
increases in compression ratio due to variable valve timing, more aggressive spark control,
and more efficient combustion which will improve f.e. of the engine.


Tom Vaught
Boosted Engine Design Engineer

Eventually we installed a Method #3 system on Coletti's truck with the help of one of his engineers,
Jeff Feit. Coletti filed for a patent for that chilled A/C system and received it about 3 years later.
It was in his name so the "copy cats" who are using a system like that may be getting a call from his
lawyers down the road when it is $$$$$ worthwile.

Tom V.

 

A turbo conversion business I worked for built a Method 1 system for a customer in 1980. L20 Nissan engine on 25 psi (which was a lot in those days.)

I am often surprised at patents that are issued eg Alfadan has a recent patent on the Scotch Yoke as a replacement for con rods in a 4 cylinder outboard. WTF??

 

I saw a Patent and Parts/Pictures one time for a "8" shaped Dual Piston (but actually one casting) that would run in a similar "8" shaped block bore. It was a "4 Piston" engine that had the dimensions of a V-8 engine overall size.

It was apparent that they wanted to generate a great deal of force with each dual piston assembly.

Kind of like the Marine Engine you see here: Large but slow speeds. https://en.wikipedia.org/wiki/Wärtsilä-Sulzer_RTA96-C See Photo.

The Dual Piston concept was designed for marine applications with a very high torque capability but fairly low piston speeds and engine cruising rpm.

Tom V. #ad

 

. . . and the advantage of the figure-8 piston was??

For Honda the object was to keep the advantages of their V8 engine after the rules were changed to limit cylinders to four.

#ad

 

Thanks for the great newer Honda "Race Track" Piston design picture.
I never saw that picture before and my Research Pictures were dated back in the early 70s.
Tom V.

 

Must have been a nightmare manufacturing high precision oval components - pistons, bores and RINGS! Then you have another nightmare with fits and maintaining an even ring pressure all round!!!

I read an interesting article where Honda discovered the oval piston with 8 valves breathed better than 2 round pistons with 4 valves each.

 

Fairly popular with the 03/04 cobra and gen 2 lightning guys originally and now the newer mustangs is the the KILLER CHILLER setup. Which uses the AC to cool an air to water heat exchanger for the blower guys. One of my close friends has it on a 2.9 whipple cobra and it seems to be very efficient in cooling. Not sure exactly how it compares to your 3 examples tho.

 

Here is the Patent Number for O.J. Coletti's Patent he filed on the work that Jeff Feit and I did on the SVO A/C Super Cooler system. https://patents.google.com/patent/US6006540A/en
He authorized the work on the system. Not sure if He filed it under his personal name vs FMC but that really does not matter to me.

https://www.hagerty.com/media/car-profiles/the-ford-svt-lightning-that-never-was/

"The most interesting feature Ford previewed was a device called Super Cooler using the truck’s A/C system to lower the temperature in a coolant tank to 30 degrees F. On demand, the chilled fluid would be routed through the supercharger’s intercooler to remove 20-percent additional heat from the incoming air. SVT boss O.J. Coletti was granted U.S. patent 6006540A for this clever invention in 1999. Naturally, it was nicknamed ‘Cool-etti.’ "

The way it actually worked was that the A/C system had a small custom made Evaporator installed in the water tank cooling the water in that tank. A normal water to air Inter-cooler circuit took that chilled water from the tank and sent it to a water to air Intercooler after the supercharger to chill the supercharged (compressed and hot) charge air.
Coletti got the patent, I had fun designing the system with Jeff Feit, and the A/C cooling expert in Ford. It worked very well. No more bagged ice runs at the race track.

Tom Vaught

The other A/C cooling guys better watch out. Looked what happened when Holley went after Barry Grant for copying their Holley carb calibrations.

 

The biggest benefit to super-cooling is not buying out the store for ice each time you go to the drag strip.
But $$$ over time either way. Adapting a A/C system to a race car will not be cheap either.

Tom V.

 

Working with a guy on a staged inter-cooler system.
Lower boost (20 psi), air to air inter-cooler.
Higher boost, 30-40 psi, utilize a 2 stage system that drops the charge temps to 180 degree temps using a ice water tank, a high volume coolant pump system, and a very good water to air inter-cooler prior to passing thru the Throttle Body.

Just trying to keep the same max 180 degree temps even at the much higher boost pressures.
Cruising the air to air system would be on, for higher boost "testing" the additional charge cooling would come from the
Water system.

Tom V.