THIS CAR TRAVELS 75 MILES ON A SINGLE GALLON OF GASOLINE!

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The little car will accelerate from 0 to 60 miles per hour in a very satisfying eight seconds. Furthermore, under "no wind" conditions, the automobile can cruise down the highway at a steady 70 mph ... while carrying a reserve in its accumulators that will push it on up to higher speeds for a short distance. And it does all this on a maximum fuel consumption of .9 gallons per hour ... which works out to a shade better than 75 miles per gallon. (Are you paying attention, Detroit?)

Still, Ernie's class is quick to point out that its car can be improved a great deal more. One of the most obvious refinements, the students say, will be the elimination of the vehicle's VW transaxle. "We left the transaxle in so we wouldn't have to redesign the VW chassis's suspension," they point out, "which means -since nothing is 100% efficient-that we've combined the inefficiencies of our hydraulic drive with the well-known inefficiencies of the old mechanical drive. If and when we couple our hydraulic motor directly to the car's wheels, we should realize a marked improvement in our car's efficiency."

THE SAME, YET DIFFERENT

The Hennepin Tech students' energy storage transmission is, in some ways, quite similar to Vince Carman's Inertial Storage Transmission featured in MOTHER NO. 48. Both use off-the-shelf hardware and well-proven technology. Both dramatically extend an automobile's gasoline mileage by capturing, storing in an accumulator, and later using the energy that ordinary automobiles normally waste during braking and when they are idled in city traffic with their engines running.

But the two transmissions are quite different too. Carman, for instance, uses "fixed displacement" pumps and motors in his hydraulic drive train because he feels that they're the most efficient ... while the HVTC student team chose "variable displacement" hardware because such pumps and motors are easier to control.

Another major difference: The Portland car's engine is run at a constant rpm and is turned off as soon as it has pumped a predetermined pressure into the accumulator in its hydraulic drive line. In the Minneapolis vehicle, on the other hand, the engine's rpm is allowed to vary according to the amount of pressure that is in the drive line's accumulator and how fast that pressure is being drawn off ... and the powerplant is almost never shut completely down while the car is moving.

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