Prototype: Vincent Carman's Inertial Storage Transmission


Believe it or not, both these old beat up cars have something amazing in common: They get double the gas mileage of standard models, because of an ingenious new transmission system developed by inventor Vincent Carman (seriously, could your name be any more perfect for making cars?). Not only that, but he did it in the 1970's! Even more unbelievable (or maybe not, considering) is that the government was sandbagging the implementation of his innovation for 2 years...Carman's transmission relies on hydraulic fluid under pressure to transfer energy from the engine to the wheels. A major downside of piston engines is that they are most efficient at a very high RPM -- much higher than would be effective for starting. So, in current cars, manual, or automatic mechanical transmissions try to use gearing to keep the engine running at its optimum RPM. But these systems inevitably run the engine too slow or too fast, because there are just not enough gears to cover everything. Some recent cars (like the Honda Insight and Toyota Prius) have used continuously variable transmissions which theoretically have infinitely many gears, to make an even more efficient motor running profile. But problems still happen when the car is starting (since the engine starts from rest, and is therefore inefficient), and when it accelerates quickly from a stop.

The Inertial Storage Transmission (IST) that Carman developed bypasses all these problems by storing the engine's energy in high-pressure fluid. The fluid is pumped out of a reservoir by a small gas engine, into an accumulator at high pressure, which holds the fluid like a super-soaker holds water. Then, based on acceleration, more or less high pressure fluid is fed out of the reservoir through a hydraulic motor (like a turbine) to drive the wheels.

The system works almost identically to current hybrid electric systems, with some major advantages. First, it's cheap; hydraulics are a common technology with low service costs and cheap materials. Second, there are no expensive batteries or electronic systems to damage. And third, energy loss in pressurizing the accumulator tank is much less than for charging batteries.

So what held up this wonder? It looks like the usual bureaucratic nonsense. Some people loved it. Some people hated it. Some think it just wouldn't work. And yet Vincent has been drove a version of this car for two years with no trouble. Did we mention that this was in 1977! Surely we've worked out the kinks since then. He was getting 40 miles per gallon in a real junker of a car. If you're a handyman, this might be a project worth resurrecting. And, if you know anyone in the automotive lobby, I'm sure that Vincent would be much obliged for any mention.
:: IST at Mother Earth News [by DM]