Chapter 1: Development of Off-Road Vehicles

BAE 517 - Lecture 1

Tractor

Words origin came from England. Was used as a synonym for “traction engine.”

The word “tractor” appears in an 1890 patent for “track-laying, steamtraction engine.”

Poor traction plaqued early steamtraction engine designers. Solution: bigger wheels (36 ton traction engine with 5 m wide by 3 m dia. rear wheels).

Other solutions included the development of track-type tractors in the early 1900s.

Gasoline Engine

Need for reducing the number of workers required to operate steamtraction engines.

First comparisons of steam and gas engines occurred at the Winnipeg Tractor Trials (1908-1912).

First U.S. demonstration was held in Omaha, Nebraska in 1911 as an exhibition, not competition.

Nebraska passes tractor test law in 1919.

Nebraska Tractor Test Law

All tractor makes and models sold in Nebraska must be tested, with published results.

Manufacturers required to provide a reasonable supply of repair parts.

Tractor tests attained worldwide recognition

Tractor tests provided standards for performance.

History of Vehicle Development

1858 - Fawkes steam plowing engine. 1873 – Parvins steamer first track laying

device in U.S. 1876 – Otto received patents for IC

engine. 1889 – One company builds tractor with IC

engine. 1908 – Winnipeg Tractor Trials 1911 – First tractor demonstration in

Omaha, NE.

History of Vehicle Development Cont.

1917 – First cast iron used in tractor chassis (Fordson).

1917 – First oil cooled clutch faces (Fordson).

1919 – Nebraska Tractor Test Law passed.

1919 – First PTO introduced (International 8-16).

History of Vehicle Development Cont.

1920 – First tractor tested in Nebraska (John Deere Waterloo Boy).

1924 – First successful row-crop tractor marketed (McCormick-Deering Farmall Regular).

1927 – Mechanical rockshaft lift for mounted equipment introduced (John Deere Model GP).

1931 – Caterpillar introduces diesel engine (84 Hp).

History of Vehicle Development Cont.

1932 – Firestone Rubber introduces first rubber tires (Allis-Chalmers Model U).

1936 – Hydraulic rockshaft replaces mechanical rockshaft (John Deere Model A).

High compression engine introduced by Oliver, used fuel with octane rating of 70, improved fuel economy and more power (Oliver HC 70).

History of Vehicle Development Cont.

1938 – Machinery companies hire styling consultants (IH hire Raymond Lowery and Deere hires Henry Dreyfuss Associates).

1938 – Weight transfer hitch introduced by Ford, hydraulics lifted hitch to improve traction (Ford 9N).

1941 – LPG tractor engines introduced by Minneapolis Moline.

1940-1949 Remote hydraulic cylinders were adopted to

and standardized by SAE and ASAE. Live power take-off introduced.

History of Vehicle Development Cont.

1950-1959 Power of tractors increases rapidly. Percentage of diesel tractors increases. Large 4WD tractors developed for the

wheatlands. LPG tractors decline. Refinements include: power steering,

automatic transmissions, and more forward gear ratios.

History of Vehicle Development Cont.

1960-1969 Power of tractors continues to increase. Most large tractors are diesel. More emphasis on operator comfort

and safety. Full power-shift transmission become

available. Ergonomic seats with suspensions are

widely adopted. Radial-ply tires are introduced.

History of Vehicle Development Cont.

1970-1979 Turbochargers and intercoolers added to diesel

tractors. ROPS available, and beginning in 1976 were

required for all new tractors sold for use by employees.

Cabs common on large tractors. Sound pressure level measurements added to

Nebraska Tractor Tests (1970). Last gasoline engines tractors tested at

Nebraska (1978). Percentage of tractors over 75 kW in North

America continues to increase.

History of Vehicle Development Cont.

1980-2000 Tractors equipped with electronic controls and

sensing. Nebraska conforms to OECD internationally

accepted codes. First Nebraska 3-point hitch lift test conducted

(1984). Introduction of rubber-belted agricultural

vehicles. Tractor power appears to reach upper limit of

300 kW. Number of utility (landscape and garden

tractors) expands rapidly.

Types of Off-Road Vehicles

Crawler Standard Row-

Crop High-Clearance Utility Orchard Lawn and Garden Multipurpose

Power Tiller Tree Skidder Skid-Steer Loader Two Wheel Drive

(2WD) Front Wheel Assist

(FWA) Four Wheel Drive

(4WD)

Global Variations in Tractors

Rice tires are used in Japan. Power/weight ratios are greater for

tractors in Japan. Radial-ply tires are common in Europe. Tractors outside of North America have

up to four PTO speeds. Crawler tractors are more popular in

Europe and UK. Power tillers are common in Asia.

Implement Applications

Attachments/implements are coupled to tractors using the following methods: Towed (single hitch point) Mounted/Integral (three point hitch) Semi-Mounted/Semi-Integral (two point

hitch) Frame Mounted

Energy Conversion Devices

Human/Animal Energy Piston Engines Compression Ignition

(Diesel) Engines Spark Ignition

(Gasoline) Engines Gas Turbines Wankel Rotary

Engines Free-Piston Engines Sterling Engines

Steam Piston Engine Steam Turbine Engine Thermoelectricity Fuel Cell Solar Cell Electric Motor and

Generator Storage Battery Magnetohydrodynami

c Device

Carnot Efficiency

h

lh

T

TTe

wheree – Carnot EfficiencyTh – High TemperatureTl – Low Temperature

Future Engine Designs

Piston CI engine is well established and not likely to be replaced soon.

Ceramics will likely be incorporated into designs of the future for increased operating temperature and reduced wear.

Look for electric drives for cooling (air and water movement) and lubrication.

Trends in Tractor Design

Total weight reduction of tractor and implements.

Front and rear mounted implements. Lighter, high power tractors will transfer

power through PTO. Power transfer will be controlled

automatically. Driver comfort and safety will be

improved.