BillyShope
Automotive
- Sep 5, 2003
- 263
Was reminded, the other day, of a GM project of the early sixties. This got as far as a six cylinder Chevrolet with a small, positive displacement compressor which slowly charged a tank with high pressure air. So, what can you do with a tank of high pressure air? Well, they squirted it back into the carburetor inlet, entraining additional ambient air and thereby increasing engine performance. Yeah, it sounds like one of those small ads at the back of "Popular Mechanix," but anecdotal reports claim the car performed like an eight.
(The idea of all this, of course, was to efficiently provide short bursts of performance without seriously affecting the mileage of the car.)
So, with improved engine control electronics and fuel injection, what could be done today with this concept? My first thought was to dump the air upstream of the throttle body and downstream of a solenoid actuated valve. There would, of course, be a pressure regulating valve at the tank outlet. But, when I calculated tank size, I was surprised to find that maximum charging pressure did not have as great an effect as I had hoped. Supplying the energy for the drop across the regulator is the "killer." Minimum tank volume is achieved with infinite pressure. (In other words, there is no convenient optimum relationship between tank volume and a reasonable pressure.) I was looking at 7 psig, a 2 liter engine, and 10 seconds of usage and the tank would simply take up too much of that precious underhood space.
Which brings me back to the air entrainment concept and my question. GM, as I recall, dumped axially into a round conduit. Seems to me that you'd want to use a duct with high L/W ratio for maximum entrainment. Has anybody done any work along this line?
(The idea of all this, of course, was to efficiently provide short bursts of performance without seriously affecting the mileage of the car.)
So, with improved engine control electronics and fuel injection, what could be done today with this concept? My first thought was to dump the air upstream of the throttle body and downstream of a solenoid actuated valve. There would, of course, be a pressure regulating valve at the tank outlet. But, when I calculated tank size, I was surprised to find that maximum charging pressure did not have as great an effect as I had hoped. Supplying the energy for the drop across the regulator is the "killer." Minimum tank volume is achieved with infinite pressure. (In other words, there is no convenient optimum relationship between tank volume and a reasonable pressure.) I was looking at 7 psig, a 2 liter engine, and 10 seconds of usage and the tank would simply take up too much of that precious underhood space.
Which brings me back to the air entrainment concept and my question. GM, as I recall, dumped axially into a round conduit. Seems to me that you'd want to use a duct with high L/W ratio for maximum entrainment. Has anybody done any work along this line?
