Project Report (2)

1

“Performance Improvement of (1625) Old Tender AC Buses”

Prepared by:-KUMAR UJJAWAL Mentor:- Neeraj K. Sharma

2

SCOPE

Increase the availability of old AC buses.

Reduce the breakdown of old AC buses.

Reduce the V-belt premature failure of old AC buses.

Reduce the bolt broken cases of flywheel housing and chassis crack in old AC buses.

Reduce coil ignition failure in old AC buses.

Reduce the Engine failure by identifying the root cause.

Reduce the part consumption of old AC buses.

3

Issues in (1625) old Tender AC Buses

Non Availability of Critical Parts for Old 25 AC Buses.

In Absence of Child parts cost of whole units are very High..

Frequent Chassis Crack.

Frequent failure of Coil Ignition Failure resulting Load not Pulling.

Low Life of Recon Engine.

Frequent failure of flywheel housing mounting failure.

Frequent failure of old AC gas mass due to recurrent problem of positive supply pin broken.

4

PROJECT APPROACH

To reduce engine V–belt failure in old ac 1625 buses by using a special alignment tool for ensuring proper alignment between engine alternator pulley and fan support pulley.

To make efficient cooling system by utilizing waste AC water to reduce Engine overheat and Load not pulling cases.

To reduce the bolt broken of flywheel housing and chassis crack by ensuring proper monitoring and fitment of engine mounting pads along with re-bound rings.

5

PROJECT APPROACH

To minimize part failure of coil ignition by modifying the Ignition system which ultimately reduces the breakdown of Load not pulling in old ac buses.

To reduce the Frequent failure of old AC gas mass by understanding the root cause of failure and take preventive and corrective actions. Focus area is to reduce the positive supply pin broken.

To reduce the Engine Failure by identifying the root cause and steps to

be taken to eradicate the problem. Focus area is to prevent the dust entry into engine and study the manufacturing Defects.

6

“Alignment Tool”

7

Alignment Tool

Alignment Tool for fan support and Alternator pulley.

Location - Engine alternator & Fan support pulley.

Purpose : To adjust alignment between alternator and fan support pulley for avoiding v-belt broken cases

Complaint: V-belt broken due to misalignment of engine alternator pulley in 1625 buses as retro of engine alternator done in these buses from 70amp to 90amp.

8

Alignment Tool

9

Alignment Tool

10

Alignment Tool

Advantage Easy checking and time saving tool.

Avoid error as gives idea about misalignment easily and adjustment can be done.

Easy to handle.

Low tooling cost.

Cost Saving tool by reducing the possibilities of coolant throw and engine overheat due to v-belt broken.

11

“Efficient Cooling System”

12

Efficient Cooling System

Efficient cooling system by utilizing waste AC water.

As the condensed water from AC system get wasted through four water channels located at corners of bus. We collect that AC water into a reservoir tank for special designed setup which acts as a Intercooler to provide the additional cooling. This special designed setup is mounted on Intercooler itself for providing additional cooling .

13

Design Consideration

Good conductive material. Corrosion resistant. Economical. Volume of water to be circulated . Temperature of AC water. Temperature near Intercooler area. Recirculation of water. Clearance in Design for force convection. Dimensions of Cooling channels . Proper routing of coolant pipes. Leak proof.

ALUMINIUM

14

Part Designing

Upper TankDimensions (39mm diameter, length 750mm &

thickness 1.5 mm)

Lower TankDimensions (39mm diameter, length 750mm &

thickness 1.5 mm)

15

Part Designing

Middle TankDimensions (39mm diameter, length 750mm &

thickness 1.5 mm)

Discharging NozzleDimensions (19mm diameter, length 38 mm &

thickness 1.5 mm)

16

Part Designing

Cooling TubeDimensions (19mm diameter, length

430 mm & thickness 1.5 mm)

Reservoir TankDimensions (length 300mm breadth 80mm &

height 60mm)

17

Complete Design

Front view Side view

18

Isometric View of Complete Design

19

Modifications

Modification on Left side of the bus.

20

Modifications

Modification on Right side of the bus.

21

Modifications

Modification behind the bus.

22

Modelling & Fitment of Reservoir Tank

Fitment of Reservoir tank Reservoir Tank .

23

Complete Modelling

24

Fitment with the Intercooler

25

Fitment of Complete Assembly in bus

26

Calculations & Results Total volume of complete assembly is 5.60ltr. Surface area of upper tank and lower tank is 93100mm2. Surface area of two Middle tank is 172354mm2. Surface area of cooling channel is 410460mm2. Surface are of Discharging nozzle 18136mm2. Total surface area of complete assembly 787152mm2. Assuming outside temperature 35 degree Celsius. Ac water temperature is around 18 degree Celsius. Intake manifold temperature is 3-4 degree Celsius cooler than normal

one. (Assuming natural convection, atmospheric temperature 35degree Celsius and heat transfer coefficient of air @35degree Celsius is 20W/m2-k) Heat dissipated by entire setup = h*A*(Tsurrounding-Tsurface) =20*787151*10^(-6)*(35-18) =267joule

27

Results

Heat dissipation will be around 267 joule.

Intake manifold temperature is 3-4 degree Celsius cooler than normal one.

28

“Modified Ignition System”

29

Modification of Ignition system in old AC buses

ISSUES IN CURRENT SYSTEM “Load not Pulling” breakdowns were constantly reported because of

frequent failure of coil ignition.

Parts availability is also an issue.

Parts Cost is very high.

No proper toolkit or procedure available for testing coil ignition.

PARAMETER 2014-2015

2015-2016

2016-2017

LNP Breakdowns 175 155 42 till dateNumber of Coil ignition

Consumed 147 217 4 till date

Coil ignition Value (in Rs) 6774280 10181640

184334 till date

30

Current v/s Modified ignition system

Current Ignition system Modified Ignition system

31

Modification of HT lead

Original HT lead(Circular part of HT lead was hindering

connection with spark plugs in 1625 Engine.)

Modified HT lead(Circular part was removed with the help of

grinder for proper connection with spark plugs)

32

Modification of Coil Ignition Mounting

Coil Ignition mounting with four grooves

.

Two grooves removed .Grooves are removed such that it can be welded

again to retrieve old system

33

Plates fitment on Mounting frame.

Plates made for mounting of Coil packs

Plates fitted on modified coil ignition mounting

34

Fitment Of Coil Packs On Modified Mounting

Outer Coil Pack fixed on mounting Inner Coil Pack fixed on mounting

35

Modified Orientation of ICM

ECM coupler connection is on left side and coil pack coupler connection on right side.

After reversing the orientation, sufficient increase in length for coil

pack harness

36

Results

Temporary trial of system was fitted in Bus no 911 on 7th April 2016 and without any complaints bus have covered 13610 km successfully. We have done this modification in 15 buses in which 6 of the modifications are with permanent fixtures and rest conversions with permanent fixture are in pipeline .

Another trial with permanent fixture of coil packs on modified mounting is done in Bus no 945 on 10th April and successfully running on route and covered 13930 km successfully.

KMKG of these modified buses is improved.

Modified bus monitored for knocking, engine hunting, overheating and found ok in all respect. Bus passed for PUC, CNG leak inspection after modification.

37

Results

As we have done modifications in 15 buses, so total expected number of coil ignition required is 15*6= 90

Total expected cost of coil ignition = 46083(Unit cost)*90= Rs.4147470Modification costTotal number of coil pack needed for modification 15*2=30Total cost of coil pack =15375(unit cost)*30= Rs.461250

Total number of Coil pack harness needed = 15Total cost of coil pack harness = Rs.10820(unit cost)*15=Rs.162300Total saving = Rs.4147470-(Rs.461250+Rs.162300) = Rs.3523920

If modification is done in all 25 Buses then

Total saving around 35 Lakhs till now

Total expected future saving around 59 Lakhs

38

“Frequent Bolt broken of Flywheel Housing”

39

Issues Related To Flywheel Housing

Housing Bolt getting broken and hole size gets oblong due to that housing getting damage results in huge manpower & shift loss as complete

transmission need to be put down and housing need to be repair and fitted again..

40

Action Taken

Due to unavailability of above rubber mounting and spacer buses were running with the old and damaged mounting results increase in vibrations after chasing

with parts and changing this failure is now stopped.

41

Result

First Mounting was fitted in Bus No. 0945 on 19.12.15 tillnow Bus is running fine without any bolt/ Housing broken.

Buses where we have changed this mounting with Spacers are running fine and are under observation.

Till Now we have changed these mounting in 17 Buses.

Also suspecting that this may be one of the main reason for the Chassis crack as due to the uneven vibration.

42

“Repairing of Gas Mass of Old Tender (1625) AC Buses.”

43

Issues related to old AC Gas Mass.

Frequent failure of positive supply Pin of old AC.

Due to fragility of Hot wire, it frequently gets broken.

Cost of old AC gas mass is very high.

44

Consumption of old AC Gas Mass

PARAMETER 2013-2014

2014-2015

2015-2016

2016-2017

Quantity consumed

4 0 15 0

Total cost(in Rs.) 543060 0 2036475 0

Failure only due to Hot wire and it is

retrieve by soldering the hot wire.

Failure only due to Positive supply pin

broken.

Unit cost is Rs 135765

45

Condition of Old AC Gas Mass

Condition of positive supply pin when corrosion initiated.

Condition of positive supply pin after corrosion

.

46

Sectional and Exploded view of Gas Mass

For studying the Gas Mass, We have taken the sectional view after dismantling the Gas Mass, We found that four pin that we see from outside is actually three pin and broken pin

part can be soldered the inner part of the pin.

47

For retrieving the Gas mass

Slot of housing part is cut to make sufficient clearance for soldering . Gas Mass after it gets soldered.

48

Complete Repaired Gas mass

Repaired gas mass to retrieve the OE shape.

49

Results.

After the soldering of positive supply pin, the Gas mass is working fine and it is fitted in three old AC buses for trial in the month of April and successfully covered approximately 7500km.

We have not order any Old AC gas mass in this financial year.

We reduces the part consumption old AC pertaining to Gas mass.Total cost saving = Rs 135765 (unit cost)*7= Rs 950355

Total saving till date = Rs.9.5 Lakhs

Total number of Gas Mass repaired = 7

50

“Fouling of Air Intake S pipe with the Intercooler Hose”

51

Turbo Fouling with Air Intake “S” Pipe

Due to Turbo Fouling with Air Intake “S” pipe dust enters inside the turbo and results in failure of Turbo and Engine.

52

Simple Tool that can be used to maintain the sufficient clearance between Intercooler hose and Air intake “S” pipe by ensuring the required direction of

compressor outlet

Turbo Fouling with Air Intake “S” Pipe

53

“Engine Failure of Old Tender (1625) AC Buses.”

54

Main Bearing Bolt Broken.

Case-1 (Bus no 943)

55

Seizure of Gudgeon pin Bearing.

Case-1 (Bus no 943)Details are:-Complaint :- Uneven sound was noticed from 1st Piston. Observation :-After dismantling found particles in Sump and Main Bearing Bolt, Caps found broken. Also 1st Piston Gudgeon Pin Bush found completely damaged. Air compressor, Oil level was found OK. Conclusion:- Manufacturing defect, No Maintenance lapses.Engine Life:- 5 Months(Fail KM: 35198)Engine Cost: 4,59,000.Result :- Recon convinced with investigation report and cover this engine under warranty.

56

Heavy Mixing of coolant in Engine oil.

Case-2 (Bus no 686)Details are:-Observation :-Defect: Coolant mixing in Engine oil was first observed and reported to Prolife team on 6th Feb2016 and under joint investigation all maintenance points were found ok i.e. Head gasket ,Oil Cooler, Air compressor. Only probability of internal block crack was left, hence decided to again check after refitting engine. Again heavy mixing is found on 12.03.2016 proving that it is manufacturing defect of engine. Conclusion:- Manufacturing defect, No Maintenance lapses.Engine Life:- 8 Months(Fail KM:39622)Engine Cost: 4,59,000.Result :- Recon convinced with investigation report and cover this engine under warranty.

57

During Docking while draining engine oil some metal part was observed inside

Sump.

Case-3 (Bus no 512)

After dismantling the sump, found that particles in Sump is 1st Main Bearing

Bolt.

58

Main Journal bolt broken.

Case-3 (Bus no 512)

Details are:-Complaint :- Abnormal sound was noticed from 1st Piston. Observation :-After dismantling found particles in Sump and Main Bearing Bolt, Caps found broken. Also 1st Piston Air compressor, Oil level was found OK. Conclusion:- Manufacturing defect, No Maintenance lapses.Engine Cost: 87260.

59

Main Bearing Bolt Broken.

Case-4 (Bus no 929)

60

Main Bearing Bolt broken.

Case-4 (Bus no 929)

Details are:-Complaint :- Abnormal sound was noticed from 1st Piston. Observation :-During Docking while draining engine oil some metal part was observed in Sump. After dismantling found particles in Sump and 2nd,5th and 7th Same side Main Bearing Bolt, Caps found broken. Hence it proves that this is manufacturing defect due to uneven torque at main bearings.Conclusion:- Manufacturing defect, No Maintenance lapses.Engine Cost: 4,59,000.Result :- Recon convinced with investigation report and cover this engine under warranty.

61

Milestone Achieved

Parameters Dec 2014 to

June’ 2015

Dec’2015 to June

2016

Trend

Availability of whole fleet 94.00% 95.42% 1.5%Run Km 583525 707475

21.24%Total breakdown (old AC / Total

fleet)552 / 1737

490 / 1155

11.20%

Breakdown/10k (old AC) 9.45 6.92 26.67%

Engine Overheat 28 8 71.42%

V-belt Broken 31 18 41.93%

Note:- Data is compared from December to June ( During my stay in the depot )

62

Milestone Achieved

Received Best Innovation award from Tata Motors Ltd. for reducing complain and breakdown of V-Belt broken by developing an alignment tool in the depot and only by ensuring the proper alignment of the pulley, failure is reduced up to 41.90%.

Modified ignition system of C-Gas engine bus, saving parts costing around 35 lakhs by reducing the cases of Load not pulling due to failure of coil ignition.

Design and modelling of efficient cooling system by utilizing waste AC water which acts as intercooler for reducing the cases of engine overheat and load not pulling.

63

Milestone Achieved

Cases of flywheel Housing bolt broken and chassis crack reduces significantly in old AC buses.

Reduce the failure of engine by developing the tool which ensures the compressor housing of turbocharger in such a direction so that its Intercooler hose will not get foul with air intake “s” pipe which eventually reduces the dust entry and hence engine failure

Claimed three engines under warranty by investigating root cause of engine failure and presenting the detail report before supplier.

Reduce the part consumption od old AC pertaining to Gas Mass around Rs.9.5 lakhs by only soldering the positive supply pin.

64

Recommendations & Way forward

The alignment of pulley is checked and monitored at every 15 days .

In efficient coolant system, the biggest challenge in hand is to make leak proof system. We are looking forward to make the system more spacy and leak proof by choosing Brass over Aluminum.

Modification of ignition system is under observation and we are hoping that cases of Load not Pulling get reduce in old AC buses.

We have change the 17 mounting pads of old AC buses which we found faulty at the time of Docking and ten-days and need to be replaced. We are looking forward to monitored these buses accordingly to avoid any shift loss.

Looking forward to study more cases of Engine failure.

65

Conclusion Proper alignment of belt can reduce the premature failure of V-belt.

By utilizing the AC water we can provide the additional cooling.

Modification of Ignition system in old AC buses can immensely reduce the parts consumption in old AC buses.

Cases of flywheel Housing bolt broken and chassis crack reduces significantly by only monitoring the health of mounting pads in old AC buses.

By restricting the fouling of Air intake S pipe and Intercooler hose we can reduce the engine failure.

By soldering the positive supply pin of gas mass we can retrieve the Gas mass.

66