Free Piston Tractor

| August/September 1991

  • Free Piston Tractor
    Figure 2
  • Free Piston Tractor
    Figure 1

  • Free Piston Tractor
  • Free Piston Tractor

1408 N. Van Buren, Ottumwa, IA 52501.

Reprinted with permission from the August 1957 issue of Doane's Agricultural Report, 11701 Barman Dr., St. Louis, MO 63146.

Free Piston Tractor perfected by Ford was demonstrated at the Nebraska Tractor Day. For a discussion on how this tractor works, note box.

The power stroke compresses air at b. This air bounces the pistons back for the compression stroke. During the compression stroke, air at c. is shoved through reed valves into the air 'box at a. Entrapped air in the combustion cylinder also is compressed, reaching ignition temperature at the time fuel is injected. On the power stroke (drawing 1), the pistons are forced outward by the expansion of burning gases. This movement uncovers the exhaust ports first allowing most of the heated gas to leave the cylinder through the exhaust tube. Then the intake ports are uncovered (drawing 2), and air from the air 'box' flows through the cylinder, thoroughly scavenging it and mixing with the exhaust gases. The diluted hot gases flow into a surge tank (not shown) and are released under even, steady pressure to the turbine wheel. The revolving turbine powers the tractor through reduction gears.

This tractor was developing around 50 horsepower as demonstrated. Ford engineers say it has a potential of over 100 HP without extensive changes. Noise level was not objectionable even without mufflers. It sounded similar to a 2-cylinder, 2-cycle Maytag engine.

Only a slight turbine whine was heard and this did not seem at all objectionable.