GATE Agricultural Engineering Farm Power Syllabus

Farm Power syllabus — full chapter and topic list

Expand any chapter to see its topics and sub-topics. This is the whole examinable outline for Farm Power in GATE Agricultural Engineering, not a summary of it.

1. 1

   Sources of Power

   1 topic

   • Sources of power on the farm
     • Human
     • Animal
     • Mechanical
     • Electrical
     • Wind
     • Solar
     • Biomass
     • Bio-fuels
2. 2

   Farm Power

   11 topics

   • Thermodynamic principles of I.C. engines
   • I.C. engine cycles
   • Engine components
   • Fuels and combustion
   • Lubricants and their properties
   • I.C. engine systems
     • Fuel
     • Cooling
     • Lubrication
     • Ignition
     • Electrical
     • Intake
     • Exhaust
   • Selection, operation, maintenance, and repair of I.C. engines
   • Power efficiencies and measurement
   • Calculation of power, torque, fuel consumption, heat load, and power losses
   • Performance index
   • Cost analysis of implements and tractors
3. 3

   Tractors and Power tillers

   9 topics

   • Type, selection, maintenance, and repair of tractors and power tillers
   • Tractor clutches and brakes
   • Power transmission systems
     • Gear trains
     • Differential
     • Final drives
     • Power take-off
   • Mechanics of tractor chassis
   • Traction theory
   • Three point hitches
     • Free link operations
     • Restrained link operations
   • Steering and hydraulic control systems used in tractors
   • Tractor tests and performance
   • Human engineering and safety considerations in design of tractor and agricultural implements

Farm Power flashcards for GATE Agricultural Engineering

23 of 51 cards from the Farm Power deck — real questions with worked answers.

1. What is meant by 'farm power' in agricultural engineering?

   Farm power is the energy/prime-mover capacity used to perform agricultural operations such as tillage, sowing, harvesting, pumping and processing. The main sources are human, animal, mechanical (engines/tractors), electrical, wind, solar, and biomass/bio-fuels.

2. List the major sources of power on the farm.

   Human power, animal (draught) power, mechanical power (I.C. engines/tractors), electrical power, wind power, solar power, and biomass/bio-fuel power.

3. What is the approximate continuous power output of an average human laborer doing farm work?

   About $0.1\ \text{hp}$ (roughly $75\ \text{W}$, i.e. $0.07\text{–}0.10\ \text{kW}$) on a sustained basis.

4. What is the approximate sustained power developed by a pair of bullocks (a typical draught animal)?

   A single average bullock develops about $0.5\text{–}0.75\ \text{hp}$ ($\approx 0.37\text{–}0.55\ \text{kW}$); a good pair gives roughly $1\ \text{hp}$.

5. What fraction of body weight can a draught animal typically exert as a sustained pull (draught), and for how long can it work per day?

   An animal can exert a sustained draught of about one-tenth ($\frac{1}{10}$) of its body weight and can work effectively for about 6–8 hours per day.

6. State the formula for the power developed by a draught animal in terms of pull and speed.

   $$P = \frac{F \times v}{75}\ (\text{hp})$$ where $F$ is the draught (pull) in kgf and $v$ is speed of travel in $\text{m/s}$; in SI, $P = F \times v$ in watts (F in N, v in m/s).

7. Give two advantages of animal power over mechanical power on small farms.

   Low initial and operating cost (uses farm-grown feed), no dependence on petroleum fuel, provides manure, and is suitable for small/fragmented holdings. Disadvantages: low efficiency, slow, seasonal, and requires year-round feeding even when idle.

8. Define mechanical power as a source of farm power and give its prime movers.

   Mechanical power is power obtained from internal combustion engines (petrol/diesel) used in tractors, power tillers, engines and self-propelled machines. It is the most widely used source for modern field operations.

9. What are the main advantages of electrical power on the farm?

   High efficiency, low operating cost, no exhaust/pollution at point of use, easy to control and automate, and suitable for stationary operations (pumping, threshing, grinding, dairy). Limitation: needs grid supply and is generally used only for stationary work.

10. What energy conversion does a windmill perform and what is the theoretical maximum efficiency (Betz limit) of a wind turbine?

    A windmill converts the kinetic energy of wind into mechanical/electrical energy. The maximum theoretical fraction of wind power extractable (Betz limit) is $\frac{16}{27} \approx 0.593$ (about $59.3\%$).

11. Write the expression for the power available in wind passing through a rotor of swept area $A$.

    $$P = \frac{1}{2}\,\rho\,A\,v^{3}$$ where $\rho$ is air density, $A$ is swept area, and $v$ is wind velocity. Power varies with the cube of wind speed.

12. What is the approximate value of the solar constant?

    The solar constant is about $1.36\ \text{kW/m}^{2}$ (commonly taken as $1353\text{–}1367\ \text{W/m}^{2}$), the solar radiation received per unit area just outside Earth's atmosphere at mean Sun–Earth distance.

13. Distinguish between solar thermal and solar photovoltaic (PV) energy conversion.

    Solar thermal collects radiation as heat (e.g. solar water heaters, dryers, distillation). Solar PV converts sunlight directly into electricity using semiconductor cells via the photovoltaic effect.

14. What is biomass as an energy source, and name common forms used on farms.

    Biomass is organic matter (crop residues, wood, dung, agricultural waste) used as an energy source. Forms: direct combustion (fuelwood, crop residue), biogas, producer gas (gasification), and bio-fuels (ethanol, biodiesel).

15. What is biogas, what is its main combustible component, and roughly what percentage of it is that gas?

    Biogas is produced by anaerobic digestion of organic matter. Its main combustible component is methane ($\ce{CH4}$), which forms about $50\text{–}70\%$ of biogas; the rest is mainly $\ce{CO2}$ ($\approx 30\text{–}40\%$).

16. Define bio-fuels and name the two most common liquid bio-fuels.

    Bio-fuels are liquid/gaseous fuels derived from biomass. The two most common liquid bio-fuels are bio-ethanol (from sugar/starch fermentation, blended with petrol) and biodiesel (from vegetable oils/fats via transesterification, blended with diesel).

17. What chemical process converts vegetable oils into biodiesel?

    Transesterification: vegetable oil (triglycerides) reacts with an alcohol (usually methanol) in the presence of a catalyst (e.g. KOH/NaOH) to give fatty-acid methyl esters (biodiesel) plus glycerol as a by-product.

18. State the four strokes (in order) of a four-stroke I.C. engine cycle.

    1. Suction (intake), 2. Compression, 3. Power (expansion/working), 4. Exhaust. The cycle is completed in two crankshaft revolutions ($720^{\circ}$).

19. In a four-stroke engine, how many crankshaft revolutions and how many power strokes occur per cycle?

    Two crankshaft revolutions per cycle ($720^{\circ}$) with one power stroke per cycle (so one power stroke every two revolutions).

20. In a two-stroke engine, how many revolutions and power strokes occur per cycle?

    One crankshaft revolution ($360^{\circ}$) per cycle with one power stroke every revolution — i.e. one power stroke per revolution.

21. Which thermodynamic cycle is the air-standard cycle for a petrol (spark-ignition) engine, and what process represents its heat addition?

    The Otto cycle. Heat addition occurs at constant volume (the constant-volume combustion process).

22. Which air-standard cycle represents the ideal slow-speed diesel (compression-ignition) engine, and how is heat added?

    The Diesel cycle. Heat is added at constant pressure during combustion.

23. Name the air-standard cycle that combines constant-volume and constant-pressure heat addition, used for modern high-speed diesel engines.

    The Dual (or limited-pressure / mixed) cycle, in which part of the heat is added at constant volume and part at constant pressure.

See more Farm Power flashcards →

Planning Farm Power for GATE Agricultural Engineering

Farm Power (GATE Agricultural Engineering) FAQ