Hydraulics

Don Blanky built a hydraulic car back in 1955!

Mechanix Illustrated May 1955 Inventor's Miracle Car May Revolutionize Auto Industry Will this hydraulic car revolutionize motoring? by Sam Schneider Americas's future automobile may be this hydraulically- driven, 100-mile-per-gallon vehicle, says its inventor. (click image for story)

In 1997 there was a man in Kansas City who built another Electo-Hydraulic car, a "dragster-shaped vehicle", which had "incredible" acceleration. A man from The Kansas City Star newspaper wrote the article and it was picked up by the Omaha World-Herald:

Omaha World-Herald Saturday, July 5 1997; Page 15 (click here to see article) Driven Man Creates Electric-Hydraulic Car By Joe Popper The Kansas City Star

To take it to the next step - a person could take a small car or motorcycle, complete except for not having an engine and, give it an electric-hydraulic motor that would get up to highway speeds and have good acceleration doing it, maybe even good enough for most teen-agers. Perhaps a modest goal considering what Mike did in '97.
Now, Andrew and Randy have taken it up:

Shelbyville, Times Gazette Wednesday, July 18, 2007 (click image to see article) Andrew Lamb [left] and Randy Nichols with their Electric-Hydraulic truck

Most who have gotten this far know that it is torque, not horse power, that determines a motors acceleration. It is only because, on most gasoline engines, that the torque (in pound-feet) and horsepower ratings are so very nearly the same that we can fairly well know what a cars torque, will be, just from hearing the horsepower rating. Then, knowing the weight of the vehicle, we can guess the acceleration.

However, the horsepower, needed to sustain the speed once it is attained, is far less than the torque needed to get it there. Hence, we read about ideas like shutting down half the cylinders of an engine while cruising. We don't need all the excess horsepower, what we want is the torque.

There are hydraulic motors, weighing only about 50 lbs, that have from around 200 to about 320 pound-feet of torque and, that torque exists all the way down to 0 rpm. Electric motors have torque all the way to 0 rpm also. It is basicly gasoline and diesel, internal combustion engines, that are different and need gears to keep them within their narrow range of power and torque.

Valentin hydraulic car a contender for the X-Prize