Agricultural/Bioengineering Tractor and Power Engineering 2 — Questions and Answers
Question 1: The function of a differential in a tractor axle is to:
- Multiply engine torque
- Allow drive wheels to rotate at different speeds when turning (Correct answer)
- Engage and disengage PTO power
- Reduce transmission gear ratio
Correct answer: Allow drive wheels to rotate at different speeds when turning
The differential allows the inside and outside drive wheels to rotate at different speeds during turns without binding.
Question 2: Turbocharging a diesel engine improves performance by:
- Cooling the exhaust gases before they leave the engine
- Forcing more air into the combustion chamber to allow more fuel combustion (Correct answer)
- Reducing compression ratio for efficiency
- Lowering idle speed to save fuel
Correct answer: Forcing more air into the combustion chamber to allow more fuel combustion
A turbocharger uses exhaust energy to compress intake air, increasing air density and allowing greater fuel injection for more power.
Question 3: MFWD (Mechanical Front-Wheel Drive) on a tractor improves field performance by:
- Steering only the rear wheels
- Adding drive torque to the front wheels to improve traction (Correct answer)
- Reducing overall tractor weight
- Eliminating the need for rear ballast
Correct answer: Adding drive torque to the front wheels to improve traction
MFWD engages the front axle to deliver power to all four wheels, significantly improving traction in soft or wet field conditions.
Question 4: The Nebraska Tractor Test is significant because it provides:
- Pesticide certification for tractor operators
- Standardized performance data (power, fuel efficiency, hydraulics) for tractors sold in the US (Correct answer)
- Safety ratings for rollover protection structures
- Emissions certification for diesel engines
Correct answer: Standardized performance data (power, fuel efficiency, hydraulics) for tractors sold in the US
The Nebraska Tractor Test Laboratory conducts standardized OECD tests and publishes official tractor performance data for US buyers.
Question 5: Hydraulic remote cylinders on a tractor allow the operator to:
- Control engine throttle from the cab
- Actuate external hydraulic cylinders on implements from the tractor seat (Correct answer)
- Engage four-wheel drive automatically
- Adjust tire pressure while moving
Correct answer: Actuate external hydraulic cylinders on implements from the tractor seat
Remote hydraulic couplers supply pressurized oil to implement cylinders, enabling in-cab control of equipment functions.
Question 6: In a tractor, brake horsepower (BHP) is measured at the:
- Drawbar
- PTO shaft
- Engine crankshaft (Correct answer)
- Front axle
Correct answer: Engine crankshaft
Brake horsepower is the power measured directly at the engine crankshaft before transmission and drivetrain losses.
Agricultural/Bioengineering Tractor and Power Engineering 2
The function of a differential in a tractor axle is to: