Power and its measurements

for better understanding of internal combustion engines

1. Power and its Measurements Laboratory Exercise No.2 AENGR 411: Farm Power and Energy Resources

2. Bauzon, Reynaldo, Jr. Diaz, Loieji Echanez, Marc Ren-ren Vela, Ma. Lourdes Maureen Power and its Measurements

3. Power is the rate at which work is done, it considers the length of working hours or days. There are factors that is affecting the power such as mass , momentum , inertia , torque , work and energy . There are also ways to measure those factors. I. INTRODUCTION

4. a. To measure the power delivered by an internal combustion engine b. To understand the exact technical meaning of power as well as its measurement c. To know the different factors related to the input/output of an engine d. To know the factors affecting the operation efficiencies of an internal combustion engine II. OBJECTIVES

5. a. Discussion of the following: i. Mass ii. Inertia iii. Momentum iv. Work v. Torque vi. Energy vii. Power viii. Pferdestarke III. PROCEDURES

6. b . Discussion of the following and illustration how each are determined: i. Indicated horsepower ii. Brake horsepower iii. Friction horsepower iv. Rated horsepower v. Drawbar horsepower III. PROCEDURES

7. 1. Mass - is the measurement of how much matter there is into something - is sometimes dependent on the size of the object, but still there is exception like in the balloon, even it gets bigger and bigger its mass will stay the same. IV. RESULTS AND DISCUSSION

8. 2. Inertia - the resistance of any physical object to any change in its state of motion, it includes change in speed, direction and state of rest - the tendency of an object to keep moving on a straight line at constant velocity IV. RESULTS AND DISCUSSION

9. 3. Momentum - the product of mass and velocity - term applied to a body in motion - dimensionless IV. RESULTS AND DISCUSSION

10. 4. Work - an activity involving mental and physical effort in order to achieve a purpose or result - done if a force is applied to a body and caused it to change its state of motion or if it is in motion, its rate or direction of travel is changed IV. RESULTS AND DISCUSSION

11. 4. Work work = force x distance IV. RESULTS AND DISCUSSION

12. 5 . Torque - is a twisting force that tends to cause rotation Torque = force x distance IV. RESULTS AND DISCUSSION

13. 6. Energy - the capacity of a body of doing work - grouped into two distinct classes, potential energy and kinetic energy IV. RESULTS AND DISCUSSION

14. 7. Power - the rate at which work is done - which rate is given in seconds, then power is considered as foot-pounds per second Power = work ÷ time IV. RESULTS AND DISCUSSION

15. 8 . Pferdestarke - from German words “ Pferde ” + “ Stärke ” - calque of horsepower - approximately equal to 735.5 watts IV. RESULTS AND DISCUSSION

16. 9 . Indicated Horsepower ( Ihp ) - the power generated in the cylinder and received by the piston Ihp = PLANn /(33,000x2) for 4SCE Ihp = PLANn /33,000 for 2SCE where : P=mean effective pressure, psi L=length of piston stroke, ft A=area f cylinder, sq. in N=rpm n=number of cylinders IV. RESULTS AND DISCUSSION

17. 9 . Indicated Horsepower ( Ihp ) IV. RESULTS AND DISCUSSION - it is essentially a measure of the total potential horsepower the engine is capable of developing

18. 10. Brake Horsepower ( Bhp ) - Brake or belt horse power - indicated the actual usable horsepower delivered at the engine crankshaft - it does not remain constant with changes in engine speed IV. RESULTS AND DISCUSSION

19. 10. Brake Horsepower ( Bhp ) Bhp = 2 ∏ r (torque x rpm) / 33,000 = (R x L x W) / 5252 where : R = engine rpm or speed L = length from center of flywheel to the point where beam presses on the scale, ft. W = force on scale due to friction, lbs. 1hp = 33,000 ft-lb/min IV. RESULTS AND DISCUSSION

20. 10. Brake Horsepower ( Bhp ) IV. RESULTS AND DISCUSSION Force, lb. Distance, ft. Torch wrench Rotating crankshaft Bhp = 2 ∏ r (torque x rpm) / 33,000

21. 10. Brake Horsepower ( Bhp ) IV. RESULTS AND DISCUSSION

22. 11 . Friction Horsepower ( F hp ) - part of the indicated horsepower lost because of the drag of engine parts rubbing together - actual loss will vary with engine design and use but will generally run about 10% Fhp = Ihp - Bhp IV. RESULTS AND DISCUSSION

23. 11. Friction Horsepower ( F hp ) IV. RESULTS AND DISCUSSION - Friction horsepower is determined by subtracting crankshaft Bhp from Ihp

24. 12 . Rated Horsepower ( Rhp ) - t he amount of power that the manufacturer states an engine will create at a specified engine rpm - generally, 80 % of its maximum brake horsepower IV. RESULTS AND DISCUSSION

25. 12 . Rated Horsepower ( Rhp ) IV. RESULTS AND DISCUSSION As a general rule, never load an engine to more than 80% of it’s highest Bhp rating. For example, if a job requires a horsepower loading of 8hp, you would use an engine with at least a 10hp rating. Then, the load would be no more than 80% of the engine’s maximum hp.

26. 13 . Drawbar Horsepower ( Rhp ) IV. RESULTS AND DISCUSSION power developed at the hitch or drawbar and available for pulling or similar tractive effort Dhp = (force, lb x speed, mph) / 375

27. To better understand and appreciate an internal combustion engine, knowledge about following must be considered: - technical meaning of power as well as its measurements - different factors related to the input/output of an engine - factors affecting the operation efficiencies - measurement of the power it can deliver V. CONCLUSION

28. VI. REFERENCES Print-outs Internal Combustion Engine Fundamentals. John B. Heywood. McGraw-Hill, Inc. USA. 1988 Basic of Engine Operations. The Goodheart Willcox Co., Inc AENGR411lecture handout. Emmnuel Sicat.2016 Online http://www.slideshare.net/amanina_mal/agriculture-engineeringchptr15 http://en.wikipedia.org/wiki / Others Microsoft Student 2008 Encarta Encyclopedia

29. a. Define horsepower and explain the origin of the units’ actual value . - horsepower( hp ) is a unit measurement of power - the term horsepower was adopted by Scottish engineer James Watt to compare the output of steam engines with the power of draft horses VII. SUPPLEMENTAL QUESTIONS

30. a. Define horsepower and explain the origin of the units’ actual value . VII. SUPPLEMENTAL QUESTIONS 1hp = 550 lb-ft /s = 745.7watts

31. b . A 10-hp robin gasoline engine is to be used as a prime mover for a single spindle hand tractor. If the average load will not exceed 80% how many liters of fuel will be consumed for an average of an 8-hr day operation and how much if fuel cost ₱ 49.95/L? compare this with a diesel engine of the same hp rating with fuel costing ₱ 29.95/L. heating value of the fuel is 10,500 Kcal/kg. Specific fuel consumption of diesel and gasoline engines are 0.45 lb / hp-hr and 0.7lb/ hp-hr respectively. Specific weights are 6.2 lb /gal and 7.2lab/gal for gasoline and diesel fuel, respectively. VII. SUPPLEMENTAL QUESTIONS

32. b . VII. SUPPLEMENTAL QUESTIONS

33. c . A four cylinder, four stroke cycle engine by 3 by 4 in. cylinder, developed 19 hp at 1650rpm. Assuming a mechanical efficiency of 85%, compute the IHP and MEP. VII. SUPPLEMENTAL QUESTIONS

34. d. Compute the thermal efficiency of the engine in problem b when it consumed 47 lbs of gasoline in a 4hr test . VII. SUPPLEMENTAL QUESTIONS

35. e . A tractor with 9 in. pulley is belted to a prony brake having a 24 in. pulley. If a engines pulley speed is 950 rpm, the brake arm length is 54 m. and the load in scale is 60lbs., what is the hp developed ? VII. SUPPLEMENTAL QUESTIONS

36. f. Calculate the drawbar hp requires to pull a plow with three 14in. Bottoms a rate of 3.25mph. If the draft is 8 lbs per sq.in. Of furrow section and the depth of the cut is 7 in. VII. SUPPLEMENTAL QUESTIONS

37. g . A Kubota engine is marked 6ps at 2400 rpm. How many hp is it? What is its maximum bhp ? VII. SUPPLEMENTAL QUESTIONS

38. h. A 10 hp single cylinder four cycle engine consumes 3 L/ hp of fuel. What is its thermal efficiency? If fuel costs P40.00/L how much will it consume for an 8-hr day operation? It is diesel or gasoline engine? Why so? VII. SUPPLEMENTAL QUESTIONS 83.33hp  

39. Thank you! Power and its Measurements