International Conference on Global Trends in Engineering, Technology and Management (ICGTETM-2016)
A Review on Cam Roller of Spark Ignition Petrol Engine
for Valve Mechanism Performance Enhancement
Chetana S. Chopade1,
Navneet K. Patil2
2
Student, ME Mechanical Engineering
Associate Professor
Department of Mechanical Engineering, SSBT College OF Engineering and Technology, Bambhori, Jalgaon
1
Abstract: Most of the Internal Combustion
engines have roller cam and follower mechanisms,
having a line contact between the cam and the roller
follower. In effort to improve the mechanical
efficiency of the mechanism the company requires us
to change the line contact to a point contact. Hence it
is required to change the flat roller follower to a
curved profile. The existing cam & follower
mechanisms used in Internal Combustion engines
have a line contact between them causing frictional
losses. These frictional losses in present line contact
are being considered on the higher side. These
frictional losses affect the total efficiency of an
Internal Combustion engine. The mechanical
efficiency of cam & follower mechanism is to be
increase by minimizing the frictional losses. The
roller of rocker arm of a Hero Honda passion bike is
replaced by new one to check performance
experimentally.
Keywords: Cam; Follower; Line contact; Point
Contact; Vibration Analysis;
I. INTRODUCTION
In the 21th century, with the advance
technologies the various vehicles have been modified
as per the requirement of a consumer. Sometimes
there is modified ignition system, modified shape,
different cylinder arrangements etc. Thus we have
decided to change the shape of a roller. The roller of
the cam follower mechanism is of flat type; which
makes line contact with cam. This line contact of
roller with cam will be changed to point contact by
doing modification in the geometry of a roller. The
modified geometry of a roller should satisfy
conditions:
1.
2.
3.
company.
Fig: 1. Details of Rocker Arm, cam roller
Table. 1
1
2
3
4
5
Material
Young's modulus
Poisson Ratio
Density
Yield Strength
100cr6
2.1e5MPas
0.3
7.850×10-6 Kg/mm3
410MPa
The existing cam & follower mechanisms used in
Internal Combustion engines have a line contact
between them causing frictional losses. These
frictional losses in present line contact are being
considered on the higher side. These frictional losses
affect the total efficiency of an Internal Combustion
engine.
It should make point contact with cam of
cam-follower mechanism.
The values of stresses of an original geometry
and modified geometry should be within
limit.
The value of frequencies of an original
geometry and modified geometry should be
within range.
Fig. 2. Existing Cam-Follower
The dimensions required for roller is measured
manually by using vernier caliper are the workshop of
a college as shown in figure 1 below. Another data
required for analysis of a roller is given by a
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International Conference on Global Trends in Engineering, Technology and Management (ICGTETM-2016)
II. TEST CRITERIA
1. Roller dimensions of Old Line & New Point
contact roller
Total 4 tests are conducted on motorcycle engine
(Hero Honda passion) with replaced Stainless
tungsten chrome steel roller –(N8) which is case
hardened & with old roller also.
Measurement of vibration parameters with
engine of hero Honda passion motorcycle to get a
average reading. These tests are taken for old and
new roller that is line and point contact type. These
readings are stored in FFT analyser and later on
analysed in mat lab to produce graphs.
III. RESULT AND DISCUSSION
1. TIME DOMAIN ANALYSIS OF VIBRATION
SIGNAL (with old line contact roller)
old line contact roller.
Measurement of Noise with old line contact
roller.
Measurement of vibration parameters with
new modified point contact roller.
Measurement of noise with new modified
point contact roller.
2. Experimental set up of vibration parameters with
old line contact and new modified contact roller
Graph 1: Time domain Analysis of vibration signal
Above Graph shows Maximum amplitude is 11mm
shown in graph which is very high need to be
reduced. Time span is taken 15 seconds for every
reading.
2. TIME DOMAIN ANALYSI S OF VIBRATION
SIGNAL (with new modified point contact roller)
Fig 3: Measurement of vibration parameters with old line
and new modified contact roller
3. Experimental set up of noise with old line
and new modified point contact roller
Graph 2: Time domain Analysis of vibration signal
Above Graph shows maximum amplitude is
3mm shown in graph which is very low i.e. reduced.
Time span is taken 15 seconds for every reading. In
old roller it was 11 mm so high. Hence our
optimization is successful. The amplitude level
decreases considerably by new roller.
Fig 4: Measurement of noise with old line and new modified point
contact roller
Above (Photo) shows that noise test is going
on with the noise sensor probe held in hand at the
approximately same distance for all four sides of I C
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International Conference on Global Trends in Engineering, Technology and Management (ICGTETM-2016)
IV. TIME DOMAIN ANALYSIS OF ACOUSTIC
(NOISE) signal old roller
VI. RMS VALUE
VIBRATION
ACOUSTIC
Graph 3: Ti me domain Analysis of acoustic (noise) signal
Above Graph shows Maximum amplitude is 50000
DB shown in graph which is very high need to be
reduced. Time span is taken 15 seconds for every
reading.
V TIME DOMAIN ANALYSIS OF ACOUSTIC
(NOISE) signal New roller
Graph 4: Time domain Analysis of acoustic (noise) signal Above
Graph shows Maximum amplitude is 45000
New roller
0.9331
13404.7
Old roller
1.0233
14624.2
Modal & stress analysis of existing and
modified follower is carried out. As per the
conditions initially frequency range was fixed and
then the Modal analysis is performed. Frequency
range of modified roller follower shows a very good
match with the frequency range of existing roller
follower. The obtained frequency range of existing
roller follower is 828.32 HZ to 3272.8 HZ and for
modified roller is 953.60 HZ to 3162.7 Hz .As
frequency range of modified roller follower is within
the frequency range of existing roller follower. Thus,
the modified design proves to be safe. From modal
analysis it is observed that the maximum values of
deformation for modified roller follower is 21.675
mm, while for existing roller follower is 23.41 mm
for the obtained frequency& in case of static stress
analysis value of deformation in both cases is very
small or it negligible. This shows modified roller
follower deforms comparatively less as compared
existing roller follower in case model analysis. This
indicates change of the flat face of roller follower to a
curved face roller follower mechanism results in low
frictional losses due to point contact which results in
improved in mechanical efficiency of internal
combustion engine.
DB shown in graph which is reduced. Time
span is taken 15 seconds for every reading. The
amplitude level decrease s considerably by new
optimized roller. Hence our optimization is
successful. The amplitude level decreases
considerably by new roller.
Vibration spectral analysis
Comparison of effect on amplitude & frequency by
both rollers with old line contact roller. Shows the
vibration spectrum of old roller at idling speed of
motorcycle (pink line) and with new modified point
contact roller (black line)
Graph 5: Comparison of effect on amplitude & frequency by both
rollers
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Chart 1. Result Analysis
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International Conference on Global Trends in Engineering, Technology and Management (ICGTETM-2016)
VII. CONCLUSION
The change of roller can significantly reduce
the costs of maintenance. In this research, vibration
and acoustic signals were used in an engine of
motorcycle. It was shown that various types of
signals can be detected successfully by both types of
rollers by acoustic and vibration signals analysis. The
acoustic analysis method has gained wide industrial
acceptance for engine condition monitoring. In this
dissertation work, experimentation is carried out to
vibration & noise level difference through acoustic
and vibration analysis and feasibility of practical
application of new modified roller in engine of
motorcycle is investigated. The acoustic and
vibration spectrums obtained for different rollers are
presented on which following conclusions can be
drawn.
1. Using Frequency Domain Spectrums
With new point contact roller & old line contact
roller a comparison shown that it reflects the change
in spectrum. It is observed from the amplitude of
frequency has decreased considerably.
2. Using Time Domain Spectrums
With comparison of time domain spectrum, it is
observed that an RMS value was decreased by the
use of new point contact roller in engine of
motorcycle.
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ISSN: 2231-5381
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