Engine Testing Shop 2e4p46

ENGINE TESTING SHOP INTRODUCTION: In this shop, testing of various parameters of engine is done after their dispatch from engine assembly shop. It deals with testing of specific fuel consumption, torque obtained, working temperature and tapping clearance between inlet and exhaust valve and rocker arms.

This process is done on a machine known as ‘engine testing bed’, having three gauges, one of which shows specific fuel consumption i.e. Time in which 100 c.c. of fuel is consumed. Second gauge shows torque obtained at specific r.p.m. and third gauge shows temperature of engine at that time. The required temperature for testing engine is 75 C, which is known as ‘Working temperature’.

The testing of engine is done at three r.p.m.’s of engine i.e. Idle r.p.m., Flyup r.p.m. and Rated r.p.m.

IDLE r.p.m: The normal r.p.m. with which engine works without application of accelerator is known as idle r.p.m. It is about 500-600.

FLY-UP r.p.m: The maximum r.p.m. of engine on pressing full accelerator is known as Fly-up r.p.m. Its value is about 2200-2300.

RATED r.p.m: The maximum r.p.m’s attained by engine at maximum torque is known as rated r.p.m. Its value is about 2100.

The engine is mounted on engine testing bed and exhaust pipe is connected to another pipe, which causes exhaust gases to flow into atmosphere. The engine is started by means of electric stator and allowed to run for about 1 hour and 50 minutes so that its temperature becomes equal to working temperature (75 C). The engine is then tested at various conditions and at various r.p.m’s as mentioned above.

ENGINE TESTING PROCEDURE: ACTIVITY SCHEDULE: 1. While running engine, at idle r.p.m check: : - Lubrication of piston rods. : - Leakage of oil, fuel and water. : - Lubrication of rocker arms.

2. Loading of engine: -

: - Check and record water temperature and oil pressure after completion of every sequence. : - Tighten cylinder head balls. : - Re-adjust value clearances and lock adjusting nuts. The tapping clearance between inlet valve and rocker arm should be 0.3 mm and between exhaust valve and rocker arm should be 0.4 mm. : - Check and record fuel time for 100 c at rated r.p.m and at full load. : - Check and record idle and fly-up r.p.m. : - Total cycle time of engine testing is 1 hour and 50 minutes.

MODEL OIL IN ENGINE OIL IDLING FLY-UP RATED CYL.HEAD TAPPET LOAD(NM) F.I.P. IN SUMP+ RPM RPM RPM NUT/BOLT CLEAR- CORR. (LTRS.) FILTERS TORQUE ANCE POWER (LTRS.) (m-kg) (mm) (PS) INLET EXIT 2522 0.2 6.0 500-600 2245-2330 2100 21-22 0.3 0.4 75-81/ 2522OS 24+1 3522 0.3 9.2 500-600 2245-2330 2100 21-22 0.3 0.4 106-115/ 34,+1.4 4022 0.3 9.2 500-600 2245-2330 2100 21-22 0.3 0.4 123-133/ 39.5+1.6 4922 0.3 9.2 500-600 2245-2330 2100 21-22 0.3 0.4 141-153/ 42.5,+2 6522 0.3 9.2 500-600 2245-2330 2100 21-22 0.3 0.4 178-194/ 42.5.+2.4 7511 0.3 9.2 500-600 2245-2330 2100 21-22 0.3 0.4 223-242/ 75,+3

Fuel time For 100 C (Sec)

Corrected SFC (g/PS.h) max.

Oil pressure (kg/cm2) Injection oct.2005 At idle At rated Timing onward r.p.m. r.p.m. (Stage-2) (Stage-3)

Model

64 min.

185

1.0 min.

3.5, +1.5

16, +1

14, +1

46 min.

185

1.0 min.

3.5, +1.5

16, +1

14, +1

2522/ 2522OS 3522

41-43 min.

185

1.0 min.

3.5, +1.5

18, +1

14, +1

4022

35-36 min.

185

1.0 min.

3.5, +1.5

18, +1

14, +1

4922

26-28.5min.

185

1.0 min.

3.5, +1.5

21, +1

14, +1

6522

22-23.5 min.

172, +5

1.0 min.

3.5, +1.5

21, +1

14, +1

7511

Sr. no. 1.

Running time (In minutes) 10

RPM

LOAD

700

NIL

2.

20

1000

20

3.

30

1400

50

4.

30

1700

75

5.

10

1600

75

6.

5

1800

100

7.

5

2100 (RATED)

100

Corrected power = Load (Nm)*RPM 7023.746*C.F. Where, C.F. = [P/750]0.65 * [273+27/273+T]0.5 P is atmospheric pressure (mm of hg) T is ambient temperature (C) Corrected S.F.C.= VOLUME OF FUEL*3600*0.825 FUEL TIME*CORRECTED POWER Where, volume of fuel is 100 c.c. and fuel time is in seconds. The load values (Nm) are based upon correction factor of 0.97. In extreme winter, 2% extra load should be added to maximum load and during extreme summer, 2% load should be subtracted from minimum load.