SID Report

ME 515: DESIGN PROJECT
Instructor: Dr. M.Y.
Khaled
SPRING-2015
4 CYLINDER 4 STROKE IN-LINE ENGINE
Presented by
Siddhesh Sawant

ME 515 – Siddhesh Sawant
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CONTENTS
1. INTRODUCTION…………………………………………………………………………2
2. PROBLEM STATEMENT……………………………………………………………..4
3. ENGINE SPECIFICATION…………………………………………………………….5
4. PERFORMANCE RESULT…………………………………………………………..10
5. CRANK-PHASE DIAGRAM………………………………………………………..11
6. SHAKING FORCES AND SHAKING TORQUE……………………………….15
7. GAS FORCE AND GAS TORQUE………………………………………………..19
8. EVEN FIRING…………………………………………………………………………..22
9. CONCLUSION………………………………………………………………………….23
10. REFERENCES………………………………………………………………………….24

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1.INTRODUCTION
We almost take our Internal Combustion Engines for granted don’t we? All we do is buy our
vehicles, hop in and drive around. There is, however, a history of development to know about.
The compact, well-toned, powerful and surprisingly quiet engine that seems to be purr under your
vehicle’s hood just wasn’t the tame beast it seems to be now. It was loud, it used to roar and it
used to be rather bulky. In fact, one of the very first engines that had been conceived wasn’t even
like the engine we know so well of today.
An internal combustion engine is defined as an engine in which the chemical energy of the fuel is
released inside the engine and used directly for mechanical work, as opposed to an external
combustion engine in which a separate combustor is used to burn the fuel. The internal
combustion engine was conceived and developed in the late 1800s. It has had a significant impact
on society, and is considered one of the most significant inventions of the last century.
The internal combustion engine has been the foundation for the successful development of many
commercial technologies. For example, consider how this type of engine has transformed the
transportation industry, allowing the invention and improvement of automobiles, trucks,
airplanes and trains.
Internal combustion engines can deliver power in the range from 0.01 kW to 20x103 kW,
depending on their displacement. The complete in the market place with electric motors, gas
turbines and steam engines. The major applications are in the vehicle (automobile and truck),
railroad, marine, aircraft, home use and stationary areas. The vast majority of internal combustion
engines are produced for vehicular applications, requiring a power output on the order of 102 kW.
Next to that internal combustion engines have become the dominant prime mover technology in
several areas. For example, in 1900 most automobiles were steam or electrically powered, but by
1900 most automobiles were powered by gasoline engines. As of year 2000, in the United States
alone there are about 200 million motor vehicles powered by internal combustion engines. In
1900, steam engine were used to power ships and railroad locomotives; today two- and four-stoke
diesel engine are used. Prior to 1950, aircraft relied almost exclusively on the pistons engines.
Today gas turbines are the power plant used in large planes, and piston engines continue to
dominate the market in small planes. The adoption and continued use of the internal combustion
engine in different application areas has resulted from its relatively low cost, favourable power to
weight ratio, high efficiency, and relatively simple and robust operating characteristics.

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The components of a reciprocating internal combustion engine, block, piston, valves, crankshaft
and connecting rod have remained basically unchanged since the late 1800s. The main differences
between a modern day engine and one built 100 years ago are the thermal efficiency and the
emission level. For many years, internal combustion engine research was aimed at improving
thermal efficiency and reducing noise and vibration. As a consequence, the thermal efficiency has
increased from about 10% to values as high as 50%. Since 1970, with recognition of the importance
of air quality, there has also been a great deal of work devoted to reducing emissions from
engines. Currently, emission control requirements are one of the major factors in the design and
operation of internal combustion engines.

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2.PROBLEM STATEMENT
This graduate-level Design Project, DP, is an individual effort to examine the car-engine. The one
selected is the simplest of the 3-congigurations: In-Line, Vee, and Radial. For that reason, the 4-
cylinder/4-stroke I.C.E. is one of the most widely used engines in the automobile industry.
The Design Project comprises a Slides Presentation & Technical Report. The PowerPoint
presentation is a 5-slides show of your work as Preliminary Design Review, PDR. We have to keep
it short & sweet, with the entire class is done in 2-seessions. Put your slides on flash drive & use
the instructor’s laptop to present them. The technical report is about 20-pages, due one week
before the Final Exam. The report is a formal engineering document written by WORD & contains
text, SolidWorks drawings, photos, formulas, and calculations describing your work.
There is no handwritten content (except may be equations). Students need to address the
following loosely-defined items:
 2-Liters engine displacement.
 SolidWorks CAD design configuration.
 4-stroke cycle.
 The crank-phase diagram.
 Shaking forces & moments calculations.
 Inertia forces & torques calculations.
 Construct an arrangement for even firing

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3. ENGINE SPECIFICATION
The Otto four-stroke cycle is shown in Figure. It takes four full strokes of the piston to complete
one Otto cycle. A piston stroke is defined as its travel from TDC to BDC or the reverse. Thus there
are two strokes per 3600 crank revolution and it takes 7200 of crankshaft rotation to complete
one four-stroke cycle. This engine requires at least two valves per cylinder, one for intake and one
for exhaust. For discussion, we can start the cycle at any point as it repeats every two crank
revolutions. Figure shows the intake stroke which starts with the piston at TDC. A mixture of fuel
and air is drawn into the cylinder from the induction system (the fuel injectors, or the carburetor
and intake manifold in Figure) as the piston descends to BDC, increasing the volume of the cylinder
and creating a slight negative pressure.
During the compression stroke, all valves are closed and the gas is compressed as the piston
travels from BDC to TDC. Slightly before TDC, a spark is ignited to explode the compressed gas.
The pressure from this explosion builds very quickly and pushes the piston down from TDC to BDC
during the power stroke shown in Figure. The exhaust valve is opened and the piston's exhaust
stroke from BDC to TDC pushes the spent gases out of the cylinder into the exhaust manifold and
thence to the catalytic converter for cleaning before being dumped out the tailpipe. The cycle is
then ready to repeat with another intake stroke. The valves are opened and closed at the right
times in the cycle by a camshaft which is driven in synchrony with the crankshaft by gears, chain,
or toothed belt drive.

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ENGINE DETAILS
The engine that has been chosen for this analysis is the 2003 Ford Focus engine. The following
are the data specifications for this engine.
 4 stroke 4 cylinder in-line engine
 Bore = 3.34 inches
 Stroke = 3.465 inches
 Bore/Stroke = 0.9639
 Inlet valve = 1.26 inches
 Exhaust valve = 1.14 inches
 l/r = 4
 Vd = 0.7854 * B sq. * S * N
 Vd = 1990 cc = 2 liters
 MEP = = 4 * pi * Tmax/ Vd
 MEP = 1081.09 kPa

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CAD SKETCHES
 Piston

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 Connecting rod

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 Crankshaft
 In-line/ 4 stroke/ 4 cylinder/ 0-180-180-0

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4. PERFORMANCE RESULTS
Power Calculation:
MEP = 4 * pi * Tmax/ Vd @ 5000 RPM
= 4 * 3.14 * 12 * 127.6/ 122.65
MEP = 156.80 psi @ 5000 RPM = 1081.09 kPa
Power = ω * Torque
= 2 * 3.14 * 6000/60 * torque
Power = 128.1 hP

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5.CRANK-PHASE DIAGRAM
We are using here 4cylinder in-line 4 stroke engine engine system for our study. We have four
cylinders so an arrangement of 0, 90, 180, 270 degrees seems appropriate. The delta phase angle
between them is 90 degree.
We must establish some convention for the measurement of these phase angles which will be:
1. The first (front) cylinder will be number 1 and its phase angle will always be zero. It is the
reference cylinder for all others.
2. The phase angles of all other cylinders will be measured with respect to the crank throw for
cylinder 1.
3. Phase angles are measured internal to the crankshaft that is with respect to a rotating co-
ordinate system embedded in the first crank throw.
4. Cylinders will be numbered consecutively from front to back of the engine.
The phase angles are defined in a crank phase diagram as shown in Figure for a four-cylinder, inline
engine. Figure (a) shows the crankshaft with the throws numbered clockwise around the axis. The
shaft is rotating counter clockwise. The pistons are oscillating horizontally in this diagram, along
the x axis. Cylinder 1 is shown with its piston at top dead center (TDC). Taking that position as the
starting point for the abscissas (thus time zero) in Figure (b), we plot the velocity of each piston
for two revolutions of the crank (to accommodate one complete four-stroke cycle). Piston 2
arrives at TDC 90° after piston 1 has left. Thus we say that cylinder 2 lags cylinder 1 by 90 degrees.
By convention a lagging event is defined as having a negative phase angle, shown by the clockwise
numbering of the crank throws. The velocity plots clearly show that each cylinder arrives at TDC
(zero velocity) 90° later than the one before it. Negative velocity on the plots in Figure (b) indicates
piston motion to the left (down stroke) in Figure (a); positive velocity indicates motion to the right
(up stroke).
We will assume counter clockwise rotation of all crankshafts, and all phase angles will thus be
negative. We will omit the negative signs on the listings of phase angles with the understanding
that they follow this convention.

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Figure shows the timing of events in the cycle and is a necessary and useful aid in defining our
crankshaft design. However, it is not necessary to go to the trouble of drawing the correct
sinusoidal shapes of the velocity plots to obtain the needed information.
All that is needed is a schematic indication of the relative positions within the cycle of the ups and
downs of the various cylinders. This same information is conveyed by the simplified crank phase
diagram shown in Figure. Here the piston motions are represented by rectangular blocks with a
negative block arbitrarily used to denote a piston down stroke and a positive one a piston
upstroke. It is strictly schematic. The positive and negative values of the blocks imply nothing more
than that stated. Such a schematic crank phase diagram can (and should) be drawn for any
proposed arrangement of crankshaft phase angles. To draw it, simply shift each cylinder's blocks
to the right by its phase angle with respect to the first cylinder.

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For [ 0-180-180-0 ]
We have chosen the arrangement of 0-180-180-0 for our particular engine. According to this
particular configuration the crank angle diagram that we obtain is shown in figure below.

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At 0
At -180
At -180
At 0
-2
-1
0
1
2
0 180 360 540 720
10
Exhaust
Compres
s
TDC TDC
IntakePOWER
-2
-1
0
1
2
0 180 360 540 720
2-
Exhaust Compres
s
TDC TDC
POWERIntake
-2
-1
0
1
2
0 180 360 540 720
3-
Compres Exhaust
TDC TDC
IntakePOWER
-2
-1
0
1
2
0 180 360 540 720
40
Compres Exhaust
TDC TDC
POWERIntake

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6. SHAKING FORCES AND SHAKING TORQUES IN
SINGLE CYLINDER
We want to determine the overall shaking force which results from our chosen crankshaft phase angle
arrangement. The individual cylinders will each contribute to the total shaking force. We can
superpose their effects, taking their phase shifts into account. The following equation describes this
This expression is for an unbalanced crank. In multicylinder engines each crank throw on the
crankshaft is at least counterweighted to eliminate the shaking force effects of the combined mass of
crank and conrod assumed concentrated at the crankpin. Sometimes the crank throws in a
multicylinder engine are also overbalanced, although to a lesser extent than for a one-cylinder engine.
The need for overbalancing is less if the crankshaft phase angles are arranged to cancel the effects of
the reciprocating masses at the wrist pins. This is possible except in some two-cylinder, four-stroke,
inline engines. If we provide balance masses with an mR product equal to mArA on each crank throw
as shown in Figure, the terms in equation which include mA will be eliminated, reducing it to:

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The ideal value of shaking force is zero. This expression can be zero for all values of ωt if:
Force Balance state of a four cylinder inline engine with a 0, 90, 180, 270 degrees crankshaft:
Thus, both the sine and cosine summations of any multiple of the phase angles should be zero for that
harmonic of the shaking force to be zero.
Force and moment balance state of a 4-cylinder inline engine with 0-180-180-
0 crankshaft z1 = 0, z2 = 1, z3 = 2, z4 = 3 is follows:

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We can sum moments in the plane of the cylinder about any convenient point and we can write as:
The Shaking torque is dependent on the inertia torque. This can be further understood from the below
expression.

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We see that the inertia torque has third harmonic term as well as first and second. The second
harmonic is the dominant term as it has largest coefficient because r/l is always less than 2/3.
The shaking torque is equal to inertia torque and can be represented as:
Using MATLAB software we get the following plot for the shaking forces:

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7. GAS FORCE AND GAS TORQUE
The negative sign is due to the choice of engine orientation in the coordinate system. The gas pressure
Pg in this expression is a function of crank angle rot and is defined by the thermodynamics of the
engine. A typical gas pressure curve for a four-stroke engine is shown in figure. The gas force curve
shape is identical to that of the gas pressure curve as they differ only by a constant multiplier, the
piston area Ap. Figure shows the approximation of the gas force curve used in program ENGINE for
both four- and two-stroke engines.
The approximate expression for gas torque is:
We have further calculated Gas torque using the Engine program software and plotted the graphs.

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Gas pressure graph from engine software
Gas force and Gas Torque from Engine software

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Gas Torque Plot obtained from Engine program software
Total Gas Torque obtained from Engine program software

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8. EVEN FIRING
Firing order affects the balance, noise, vibration, smoothness, and sound of the engine. Engines that
are even-firing will sound more smooth and steady, while engines that are odd, or uneven firing will
have a burble or a throaty, growling sound in the engine note, and, depending on the crankshaft
design, will often have more vibrations due to the change of power delivery.
The inertial forces, torques, and moments are only one set of criteria which need to be considered in
the design of multicylinder engines. Gas force and gas torque considerations are equally important. In
general, it is desirable to create a firing pattern among the cylinders that is evenly spaced in time. If
the cylinders fire unevenly, vibrations will be created which may be unacceptable. Smoothness of the
power pulses is desired. The power pulses depend on the stroke cycle. If the engine is a two-stroke,
there will be one power pulse per revolution in each of its n cylinders. The optimum delta phase angle
between the cylinders' crank throws for evenly spaced power pulses will then be:
For a four-stroke engine there will be one power pulse in each cylinder every two revolutions. The
optimum delta phase angle of the crank throws for evenly spaced power pulses will then be:
With help of crank phase diagram we can determine the firing order for the engine.
Some of the suggested firing orders for 4 cylinder 4 stroke inline engine are:
 1-3-4-2
Ford Taunus V4 engine
 1-2-4-3
Ford Kent engine
 1-3-2-4
Subaru 4 cylinder engine, Yamaha R1
 1-4-3-2
Volkswagen air cooled engine

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9. CONCLUSION
Thus we can come to the conclusion from this study that, for study of the engine we need to study
and verify different parameters. In this study we have studied the torque and horsepower of the
engine, crankphase angle, shaking forces and shaking torque, gas force and gas torque and suggested
different firing order.
We also understand here that with our engine configuration of 0-180-180-0 the primary shaking forces
can be eliminated but still we need to look for the secondary forces to balance the engine completely.
We have selected the 2.0 litre engine and calculated the torque and power with the help of engine
analyser software. We have then verified these results with the conventional formulas and we
conclude that they are approximately the same.
Moreover we have taken the help of theoretical formula expressions for calculating the gas force, gas
torque and we have plotted the result for the same using Engine software and we get the peak values
in permissible levels.
Similarly we used the theoretical formulas for calculating the shaking forces and shaking torque and
then we plot these with help of MATLAB program to obtain the shaking forces plot that too lies with
the permissible levels.
We finally discussed about importance of firing order and have mentioned certain firing orders that
work successfully for 4 cylinder 4 stroke inline engine and help to give maximum power and torque .
Thus we can say that all parameters are important to complete balance the engine and for the best
performance of it.

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10. REFERENCES
 http://en.wikipedia.org
 https://www.grc.nasa.gov/www/k-12/airplane/engopt.html
 https://books.google.com/books
 http://performancetrends.com/Engine-Analyzer-Pro.htm
 Dynamics of Machinery by Norton
 Engine Program Software by McGraw Hill Publication
 http://what-when-how.com/automobile/firing-order-of-cylinders-automobile/
 ASME Transactions Volume 11 by American Society of Mechanical Engineers

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