Report Sytech Copy

SEMINAR 2011 SYTECH ENGINE

SCMS SCHOOL OF ENGINEERING AND

TECHNOLOGY

DEPARTMENT OF AUTOMOBILE ENGINEERING

SEMINAR REPORT 2011-2012

SCOTCH YOKE TECHNOLOGY ENGINE

SUBMITTED BY

SOBIN JOSEPH

Register no :SAU-2884

In partial fulfilment of the requirements for the award of the degree of Bachelor of

Technology in AUTOMOBILE ENGINEERING of Mahatma Gandhi University during the

academic year 2011-2012.

DEPT OF AUTOMOBILE-SSET 1


DEPARTMENT OF AUTOMOBILE ENGINEERING

SCMS SCHOOL OF ENGINEERING AND

TECHNOLOGY

CERTIFICATE

This is to certify that this seminar titled “SCOTCH YOKE

TECHNOLOGY ENGINE” is submitted by Sobin Joseph register no: SAU-

2884 in partial fulfilment of the requirements for the award of the degree of

Bachelor of Technology in AUTOMOBILE ENGINEERING of Mahatma

Gandhi University during the academic year 2011-2012.

Staff in charge Head of Department

ACKNOWLEDGEMENT



ACKNOWLEDGMENT

I express my deep gratitude to almighty, the supreme guide, for bestowing his

blessings up on me in my entire endeavour.

I would to like to express my sincere thanks to Prof. E D MUKUNDHAN,

Head of Department of Automobile engineering for all his assistance.

I wish to express my deep sense of gratitude to Lecturer Mr. FRANCIS

THOMAS, Mr.MANOJ KUMAR B, Mr.VIPIN RAJ and Mr.ARAVIND P V,

Department of Automobile Engineering who guided me throughout the

seminar. Their overall direction and guidance have been responsible for the

successful completion of the seminar.

Finally, I would like to thank all the faculty members of the department of

Automobile Engineering and my friends for their constant support and

encouragement.



ABSTRACT

Scotch yoke is an inversion of double slider crank chain. The scotch yoke

mechanism can be used in an engine to convert the reciprocating motion of piston into the

rotary motion of the crankshaft. The engine thus build is called as a Scotch Yoke

Technology Engine or simply a “SYTech Engine”.

Added to their cost effectiveness and simplicity, the SYTech engines have many

advantages. Their width can be kept small. The short engine block and low engine height

provide the greatest freedom for the design of drag efficient bonnet styling and effective

crust zones, even in small vehicles. The absence of unbalanced inertia forces and moments

with SYTech engines reduces the need for expensive measures to reduce cabin noise and

vibrations.

SYTech engines run more quietly and smoothly for mainly three reasons: firstly, the

engines are perfectly balanced with no free inertia forces or moments, secondly, the

mechanical piston noise is very low and finally, the peak to peak variation of the output

torque are much lower under all important operating conditions.

NOx is the exhaust gas component, which is most difficult to reduce. The sinusoidal

motion of SYTech engine piston can provide up to 30% NOx reduction with no increase in

specific fuel consumption.

SYTech crank mechanism can be applied to diesel and S.I., two stroke and four

stroke engines.

The SYTech engine is tested in “dynamometer durability test” by Collins Motor

Corporation (CMC), Melbourne, Australia. The engine is also tested in the Australian

concept family car “aXcessaustralia II” during many kilometres of road running under day-

to-day traffic conditions.

Submitted by

Sobin joseph Faculty in charge



SAU-2884

CONTENTS

INTRODUCTION 5

SCOTCH YOKE MECHANISM 7

CONSTRUCTION 8

SCOTCH YOKE MECHANISM 14

WORKING 18

BALANCING OF SYTECH ENGINE 19

CONFIGURATION OF SYTECH ENGINE 20

DIFFERENCE BETWEEN SYTECH ENGINE AND CONVENTIONAL ENGINE 21

ADVANTAGES OF SYTECH ENGINE 23

THE SYTECH ENGINE IN THE NEW AXCESSAUSTRALIA HYBRID CAR

32

APPLICATIONS OF SYTECH ENGINE

33

CONCLUSION

34

REFERENCE

35



INTRODUCTION

Collins Motor Corporation(CMC) in Melbourne, Austraila had spent over about 35 million

US Dollar for research in developing a scotch yoke engine. The design represents a major

change in the way in which the internals of a piston engine are organised. For a start, the

pistons are connected solidly to the connecting rods (ie no gudgeon pins are used) and the

piston/con-rod assemblies move directly up and down the cylinder bores, with effectively

not any sideways movement at all. Furthermore, the 'big-end' of the con-rod comprises a

rectangular opening, surrounding a square bearing-block that rides on the crankshaft.

The claimed advantages of the approach include smaller engine dimensions, lower Noise,

Vibration and Harshness (NVH) levels and with the inclusion of a balance shaft almost

perfect balance. More subtle potential benefits include the fact that the piston stays at Top

Dead Centre (TDC) longer, lower emissions, and the possibility of better fuel economy

through decreased internal friction and altered valve timing.

CMC has developed a Scotch-Yoke engine technology for very compact combustion

engines with 2 to 12 cylinders. The SYTech engine can be applied to all normal types of

combustion engines with reciprocating piston motion. Prototype engines have been built in

two and four stroke version, also in spark ignition as well as compression ignition (Diesel).

In two stroke engines the firing interval of 180 degrees between the combustion strokes of

opposing pistons simplifies the crank arrangement, but increases the engine width, if the

bottom side of the pistons is to be used for the gas exchange.

The SYTech engine has shown its applications in the combustion engines(road, water, air)

and mobile power units (electric power unit, compressors).



SCOTCH YOKE MECHANISM

The Scotch Yoke mechanism is an inversion of the Double slider crank chain. It can be

used for converting rotary motion to reciprocating motion. Figure 1 shows the schematic

arrangement of the mechanism.

Figure1 Scotch Yoke

In the figure 1 is fixed. In this mechanism, when the link 2 (which corresponds to crank) rotates about B as center, the link4 (which corresponds to a frame) reciprocates. The fixed link 1 guides the frame.

This principle is used in an I.C. engine to convert reciprocating motion of the piston into rotary motion of the crank. The engine is called as a scotch Yoke Technology engine or a ‘SYTech engine.’



CONSTRUCTION

A SYtech crank mechanism replaces the arrangement of connecting rods, gudgeon pins and pistons in conventional engines with a rigid assembly of two pistons and two connecting rods and a bearing block

Figure2 Fundamental components of SYTech engine mechanism

The combustion process, fuel system, valve train, induction and ignition system are basically identical.

Crankcase and Cylinder block:

The Scotch-Yoke engine configuration is of horizontal opposed cylinder arrangement. The

engine external pumps are positioned at the middle of the engine’s cylinder arrangement.

The firing order that suits the Scotch-Yoke engine is (1, 4) - (2, 3), where there will be

double combustion processes occurring at every 180°CAdegree interval. Figure3 illustrates

this cylinders arrangement.



Figure3 cylinders arrangement.

For high-power-to-weight feature the cylinder block is usually made of cast iron or

Aluminium Alloy. The same case is applied to this engine future development work, but the

unfired test rig in this research project is only applied with Perspective material. The liners

are force-pressed into the chamber slot. There are also passages, incorporated into the

engine for the pumping and water coolant passages. Reed valve seats are located at the

middle of the block for the induction and pumping process of the piston pump. The overall

design of the cylinder block is shown in Figure4

Figure4 The main cylinder block design.

Cylinder Liners:

Most of the gasoline engines will use grey cast iron for liners. This material has the desired

casting and machining qualities, and possesses adequate mechanical feature plus attractive

mechanical properties such as strength, toughness and wear resistance. For this work, the

liner chosen is of wet-type, which is forced fitted into the cylinder chamber slot. The liner

design is shown in Figure5



Figure5 Cylinder Liner

Cylinder Head:

The cylinder head is assembled on top of the cylinder block. For this type of engine there is

no provision for poppet valve. However it provides the housing for fuel injectors (direct fuel

injection system) for future expansion. A gasket is sandwiched between the block and head

to provide for tight sealing between these engine parts. There are provisions for reed valve

mountings for the regulation of the air intake and pumping process. Also provided are the

slots for water passages specifically for the cooling of the cylinder head.shown by figure6

Figure6 The cylinder head design

Chamber:

The chamber is of symmetrical design. It is also an open chamber due to the concavity of

the cylinder head. The hemi (abridgement of hemispherical) chamber is very popular in high

performance automobiles. This chamber geometry is applied for the reference engine.

When the piston approaches TDC (at the end of the compression stroke), the

volume around the outer edges of the combustion chamber will be reduced to a small value.



The gas mixture occupies the volume at the outer volume radius of the cylinder is forced

radial inward as this outer volume is reduced to zero. This radial inward motion of the gas

mixture is called squish. During combustion, the expansion stroke begins and the volume of

the combustion chamber increases. This reverse squish helps to spread the flame front

during the latter part of combustion. Shown by figure 7

Figure7 The detail of the hemi-spherical chamber design

Intake and Exhaust Manifold:

The engine’s intake manifold consists of a pair of intake duct and a pair of pumping ducts.

The intake ducts are for the fresh charge induction purpose, while the pumping ducts are to

pump in the fresh charge into the cylinder chamber. Figure8 shows the intake manifold

design for the double action pumping.

Figure8 Intake manifold design

Exhaust manifold consists of a pair of steel exhaust ducts. The exhaust manifold is mounted to the exhaust opening of the cylinder block for the scavenging process.



Figure9 The exhaust manifold

Reed Valves:

Four pairs of reed valves are incorporated specifically to control the mixture intake. Each

pair has two-way controls of the air intake and outlet. It is designed specifically for the

double pumping of the engine’s piston pump. During induction process, one side of the reed

valve petal will lift to permit fresh charge to flow into the pumping chamber. Consequently,

during the pumping process, another reed valve will lift to allow the fresh charge to flow

into the engine cylinder. The reed petal thickness is set at 0.2-0.4 mm, where the material

could be steel, or carbon fiber. In test rig development, the carbon fiber is applied for reed

valve petals. The reed valve assembly, which consists of i.) Main body, ii.) limiter and

iii.)petal design.

Figure10 Reed valve



Figure11 The two ways control by the reed valve design.

External pump:

The two-stroke Scotch-Yoke multi-cylinder engine is to be equipped with an external air

boost pump. The pump is to be driven by the engine’s pistons linkages. It comprises of the

compression piston and cylinder that would integrate with the Scotch-Yoke crank

mechanism. The advantages of system are due its lighter material and of small size. The

piston pump is directly connected to the crank, therefore able to produce boost pressure at a

very low rpm. The C-plate type piston linkage is able to produce double action pumping in

each cylinder block at every 180° interval.



Scotch-Yoke Mechanism

The Scotch-Yoke mechanism consists of i.) Slider, ii.) C-plates, iii.) Piston heads and iv.)

Crankshaft. The Scotch-Yoke mechanism converts the reciprocating motion of the piston to

rotational sinusoidal motion, which allows the piston to repeat its movement in horizontal

plane. The crank mechanism directly influences the size of the crankcase and cylinder

block. The consideration of the clearance design for the component assemblies is important

to allow the free motion of the slider and piston. The inner body of the crankshaft, slider and

C-plate is drilled with a lubrication oil passage for reduction of wear friction.

When the piston moves from TDC to BDC, fresh charge will be induced into the

chamber. Subsequently, when the piston moves from BDC toward TDC, the fresh charge is

forced into the combustion chamber.

Sliders:

The slider moves along the locus of the rotational that would convert the sinusoidal motion

to the linear piston movement. The suitable material for slider is high carbon steel. Figure

12 shows the locus of the rotational of the slider. Figure13 on the other hand shows a pair of

journal bearings which is mounted inside the slider.



Figure12 Rotational motion of slider

Figure13 The assembly of a pair of the sliders and bearings.

C-plates:

A pair of C-plate provides the sliding plane for the slider. It is also used to thread joint with

the piston head. The suitable material for the C-plate is Alloy Steel (Cr 0.5-1.1wt %). In test

rig development, only Aluminium material is applied for C-plates assembly. Figure14

shows assembly of slider bearing with C-plate



Figure14 The assembly of slider bearing with C-plates

Piston Heads:

There are two types of piston heads design, i.e. i.) Piston head for combustion chamber and

ii.) Piston head for piston pump. The piston material should meet certain requirements such

as high hot strength, good thermal expansion and good resistance to surface abrasion to

reduce the skirt and ring groove wear. The material for the actual piston fabrication could be

either Aluminium alloy or cast Iron. In unfired test rig, only Aluminium material is applied

for piston fabrication.

Figure15 Piston head for combustion chamber

Crankshaft:

There are three crank journals on the crankshaft for the housing of the sliders. The journals

are suited to 180º of rotation to adapt the horizontal opposed cylinder design. The journal

radius distance from the origin of the crankshaft is equal to half of the stroke engine design.



The primary and secondary unbalanced inertial forces are balanced by adding

counter weights on the crankshaft.

Figure16 Crankshaft



2-stroke horizontal opposed Scotch yoke engine

WORKING

The crankpin rotates within the bearing block, which slides up and down between the

parallel surfaces formed by the bases of the two connecting rods. The crankshaft is

conventional. The piston and connecting rod assembly oscillates along the cylinder axis in a

simple harmonic or sinusoidal motion. Hence, the bearing block mounted on the crankpin

traverses a circular path around the crankshaft axis causing rotation of the crankshaft.

The bearing surfaces between the bearing block and the base of the connecting rod

are called as ‘linear slider bearings’. They operate like a combination of a hydrodynamic

and a hydrostatic bearing. The bearings are highly loaded only at times of high relative

bearing speeds (0,180, 360, 5400 crank angle). The load equals zero or is very low during

the times, when the relative motion slows down and changes direction (90, 270, 450, 6300).

Under the low speed condition, the bearing act like hydrostatic bearings with decreasing

bearing clearance, but increasing load carrying capability. At high sliding speed, an oil



wedge builds up causing the hydrodynamic action of the bearing. As figure 17 shows, the

horizontally opposed cylinder layout ensures that the load on each linear bearing is negative

for 50% of the engines operating cycle. Negative forces open up the bearing clearance,

supporting the supply of new oil into the gap between bearing plates.

Figure17 The linear bearing load and relative sliding speed at 5000 rpm

BALANCING OF SYTECH ENGINE

All moving components in the SYTech crank arrangement conduct either a rotational or a

perfectly sinusoidal linear motion. Hence, inertia forces of a higher order do not exist for a

symmetrical crank layout, the first order, inertia forces balance each other. For engines with

four and more cylinders, the horizontal distance between the cranks causes an inertial

moment around the vertical axis of the engine. Because this moment is of first order, it can

be perfectly balanced by balance weights, which rotate only with engine speed. Only the

balance shaft, which turns in the direction opposite to the engine revolution, has to exist

physically as a separate shaft. The balance weights rotating with the crankshaft can be

directly attached to it. In the case of sytech engine only one balancing shaft is needed

instead of two in conventional engines.



Figure18 Balancing of 4- cylinder SYTech Engine

CONFIGURATION OF A SYTECH ENGINE

The general description and performance of a two stroke SYTech engine is given below:

No.

Descriptions Detail

1 Engine type Type Two-stroke gasoline engine

2 Cylinder Arrangement Horizontal Opposed

3 Number of cylinders 4

4 Total Displacement, cc 500

5 Bore x Stroke, mm 57.5 x 48.0

6 Dimension, Lx Hx W mm 540.60 x 444.50 x 435.00

7 Weight, kg 43.8



No Specification Detail

1 Maximum Brake Power(kW) 37.8(8000rpm)

2 Maximum Brake Torque(Nm) 51.6(8000rpm)

3 Best Specific Fuel Consumption,BSFC, (g/kWh)

445(8000rpm)

4 Brake Mean Effective Pressure,

bar

6.49

5 Power to Weight ratio, (kg/kW) 1.16

THE DIFFERENCES BETWEEN SYTECH ENGINE AND

CONVENTIONAL ENGINE

Difference in piston motion of conventional (Conv) and of Scotch-Yoke (sy) engines can be

described by the following equations for piston position, speed and acceleration. The

dynamic mechanism differences between the conventional engine and Scotch-Yoke engine

are shown in Table. The Scotch-Yoke mechanism is simply defined in simple harmonically

sinusoidal motion. The difference between conventional engine and scotch yoke engine are

given in the table



Piston position, speed and acceleration for the conventional and the SYTech engines

are identical in their first order term, which is the only term for sinusoidal piston motion.

The higher order parts of the equations describe the more complicated motion in

conventional engines.

Figure 19 shows the different piston positions for the point of time when the

combustion has been completed. At this time, when most of the chemical energy contained

in the fuel mixture has been converted into gas pressure and temperature, the piston of the

engine with sinusoidal piston motion is, at 6000 rpm, still located 1.5 mm closer to TDC

than the piston with a conventional crank mechanism. At 1000 rpm, the difference is nearly

1mm. this means that the conventional piston has already done more than 20% of it’s travel

with less than the theoretically available gas pressure action upon it.



Figure 19 Piston position as a function of time after TDC at 1000 and 6000 rpm

With the exception of TDC and BDC, the combustion chamber volume with sinusoidal

piston motion is smaller than the volume with a normal crankshaft and connecting rod for

any given crank angle during the whole expansion stroke.

Assuming identical cylinder pressure at each piston position, which means identical

IMEP(Indicated mean effective pressure), for both engine types, the pressure curves as a

function of crank position are shown in figure 20.

Figure20 Cylinder pressure for identical IMEP



From the figure it is clear that the peak pressure is lower in SYTech engines, but the

pressure during most of the expansion strake is higher, resulting in a higher torques output

and less peak stresses in the pistons, usually, for the same torque output, the SYTech engine

needs less fuel.

Valve Timing:

The piston of an engine with sinusoidal piston motion is at every crank angle located

closer to the TDC position than the piston of a conventional engine. Only exactly at TDC

and BDC is this difference zero. The acceleration shows the biggest differences at the

extreme positions, while the differences in piston position and speed between sinusoidal and

normal piston motion are largest at around 900 crank angle. Therefore, valve events close to

the extreme positions are not significantly influenced by the type of crank mechanism. The

differences are, however, relatively large for the events of inlet valve closure and exhaust

valve opening, which take place further away from the extreme positions. Table1 shows

these differences for the examples of a SYTech engine and an equivalent conventional

engine. The ratio of connecting rod length to crank radius for the conventional comparison

engine is 3.49

IVC:600 ABCD IVO:20 BTDC

EVO:500 BBDC EVC:160 ATDC

Piston position(below TDC)

(both engine types)

Valve timing

(conventional engine)

Valve timing

(SYTech

engine)

IVO 0.03 mm 20 before TDC 20 before TDC

IVC 60.34 mm 600 after BDC 520 after BDC

EVO 64.80 mm 500 before BDC 430 before BDC

EVC 1.86 mm 160 after TDC 180 after TDC



A significant change is only required for the closing angle of the inlet valve and the

opening angle of the exhaust valve. The inlet valve of a SYTech engine has to close earlier, the

exhaust valve to open later

Ignition / Injection Timing:

The ignition angle or, in the case of Diesel engines, the injection timing needs

adjustment too. This is especially important at high engine speeds, when the ignition delay

requires an earlier angle for the best efficiency. If the start of the combustion is not retarded

for the sinusoidal piston motion, a higher cylinder pressure peak would occur than in a

conventional engine, because more chemical energy is converted close to the top position of

the piston.



Advantages of SYTECH Engine

There are several areas, where SYTech engines are superior to engines with

conventional crank mechanisms –

1. Inertia forces and moments:

Sinusoidal piston motion means sinusoidal piston speed and acceleration. As

shown in figure 21, the maximum deceleration at TDC, in the 2.2-liter SYTech

engine is around 20% lower than that in the equivalent displacement conventional

engine.

Figure21 Piston acceleration VS crank angle at 6000 rpm

From figure it is clear that conventional engines are designed to withstand

very high inertia forces around TDC with the inertia forces at BDC being much lower. In

SYTech engines, the peaks are equal at TDC and BDC.

In SYTech engines, a single balance shaft, running only at engine speed, can

be used to eliminate all free inertia forces and moments, 50% of the inertia force created

by the piston and connecting rod oscillation is balanced by counter weights on the

crankshaft, arranged opposite to crankpin. The other 50% is balanced by weights on the

balance shaft. Thus, the use of single balance shaft instead of two as in conventional

engines, reduce mechanical losses and noise in SYTech engines.



2. Improved Engine Torque Uniformity:

Even in perfectly balanced engines, inertia influences and the intermittent

combusting cycles cause the engine torque to be delivered with a high degree of non-

unifomity. Torque peaks occur with the firing stroke, negative peaks with the

compression stroke of each cylinder. But the arrangement in SYTech engines with

two opposing pistons being rigidly connected to each other causes the output torque

to be more uniform under all important operating conditions.

Figure22 Variations in torque at part load and full load

At part load, the example in figure 22 shows that the peak to peak variations

of the engine torque are reduced by 170 Nm or 44% in the SYTech engine, while at

the same speed of 3000rpm under full load conditions, the reduction is 228 Nm at

37%. The more uniform development of the produced torques puts less stress onto

all components of the drive train and can reduce gear rattle in the transmission.

Also, it leads to a more uniform engine speed, which has the positive side effect, that

all auxiliaries are exposed to less engine speed variations during each revolution and

a harmonic balancer in the crankshaft pulley might not be necessary to protect the

belts and auxiliary components from torsional vibrations of the crankshaft.



3. Noise and vibration:

The engine is one of the main sources of noise and vibration both within and

outside the cabin of a motor vehicle. Engine noise originates mainly from free

inertia forces and moments and their harmonics and from higher frequency

combustion and mechanical impact noise. It is transmitted into the cabin of the

vehicle by air, the vehicle structure and other components. Resonances and

interferences then determine the general noise level at low frequencies. The second

order cabin noise level is often used as a measure for the acoustical quality of a

vehicle, because it is especially in 4-cylinder cars, predominant and representative

for the overall noise impression. Figure 23 shows this noise level during ‘wide open

throttle’ accelerations for cars with conventional engines and for a car with a

SYTech engine.

Figure23 cabin noise during WOT accelerations in second gear

The SYTech engine showed the lowest noise level over the whole engine

speed range.

Vibration test results measured on an engine dynamometer with acceleration

sensors mounted on the generator bracket of the conventional and the SYTech

engine demonstrate the smooth operation of the SYTech engine. The reduction in

vibration amplitudes is significant at all speeds and over the whole load range.



SYTech engines run more quietly and smoothly for mainly three reasons:

firstly, the engines are perfectly balanced with no free inertia forces or moments,

secondly, the mechanical piston noise is very low and finally, the peak to peak

variations of the output torque are much lower under all important operating

conditions.

4. Fuel Consumption and Emissions:

Combustion simulations for Diesel as well as S.I. engines indicated that the

sinusoidal piston motion of SYTech engines has a positive influence on the level of

NOx emissions. For the comparison of the SYTech and the conventional engine, the

ignition timing was adjusted in two different ways as shown in figure 24.

Figure24 Test results for CMC422 SYTech engine and equivalent conventional engine

For the ‘low bsfc’ condition, a reduction in specific fuel consumption occurs

over the whole range with about the same NOx emissions under low loads and a

considerable NOx reduction at higher part load. An average of 30% reduction of

NOx emissions could be achieved. This reduction is due to a longer well time

around TDC of the pistons of SYTech engine resulting in more time being available

for the combustion.



For HC and Co, the direct influence of the type of piston motion on the

emission levels has not yet been clearly established. If a difference exists the longer

dwell time should lead to a more complete combustion, thus HC as well as co levels

will show small reductions.

5. Mechanical efficiency

SYTech engines require fewer bearings than conventional engines. The

additional linear bearings are compensated by the reduced number of main and big

end bearings and by the elimination of gudgeon pins. This leads to lower overall

frictional losses. The lower piston side forces cause less friction between pistons

and cylinders, which further reduces mechanical losses of the engine. Thus, the

mechanical losses of SYTech engine is greater than that of a conventional engine as

shown in figure 25.

Fig.25 Mechanical engine efficiency

6. Engine Size:

With their horizontally opposed cylinder layout, SYTech engines have the

low height of conventional engines. More than 150 mm height difference can be

achieved for a 2 litre engine. Also, the connecting rods of SYTech engines are

rigidly connected to the pistons and do not move vertical to the piston motion. They

can therefore be designed very short without any increase in piston side force, which



occurs with shorter connecting rods in conventional engines. With shorter

connecting rods, the engine width is reduced approximately by 62 mm. The savings

in engine heights and width allow a much lower hood line with potential advantages

on the drag coefficient. Figure 26 represents the difference in engine size of sytech

and conventional engines.

Figure26 The comparison of the Scotch-Yoke engine with the conventionalhorizontal opposed cylinder engine

7. Manufacturing costs:

Figure 15 shows the percentage of total manufacturing costs of different

engine components for a conventional and a SYTech engine. From the figure, it is

clear that the manufacturing cost of a SYTech engine is less than that of a

conventional engine. This is because the higher production cost of the SYTech

connecting rods is offset by savings from a reduced number of main and big end

bearings, the elimination of gudgeon pins and simplest crankcase and crankshaft

designs.



Figure27 Manufacturing cost difference between a conventional and SYTech engine

8. Safety:

With the application of SYTech engines, a variety of safety advantages are

achieved in ranged to ‘active’ safety, which helps to prevent accidents to happen,

and in regard to ‘passive’ safety, which helps to protect the passengers of motor

vehicles in case an accident does happen.

Active safety:

The low centre of gravity of SYTech engines, which is situated close to the

level of the crankshaft above the road, reduces the roll moment during cornering and

makes driving through sharp bends safer.

Passive safety:

The short and flat engine allows the design of larger crush zones even in very

small vehicles. Because the engine is so flat, it can slide under the passenger cabin

in case of a frontal impact.



THE SYTECH ENGINE IN THE NEW AXCESSAUSTRALIA HYBRID CAR

The Australian concept car 'aXcessaustralia II' is a serial hybrid car of the so-called

'New Generation Hybrids'. Its internal combustion engine drives an electrical power

generator. The wheels are driven by the electrical traction motor only, which receives its

energy from a combination of batteries, capacitors and the electrical power generator. In a

drive train, which consists of a combustion engine, a generator, a traction motor, two

different systems for electrical energy storage and the necessary electronics to apply the

most fuel efficient power strategy, all components require an extremely high degree of

weight optimization to avoid offsetting the fuel savings achieved with the system by an

increased overall vehicle weight. They also need to be extremely efficient in themselves.

SYTech engine contributes its share of weight savings by being lighter than

comparable conventional combustion engines and by allowing further secondary weight

savings in other vehicle components. All SYTech engines are perfectly balanced and

therefore require much less effort to isolate the vehicle cabin from engine originated noise

and vibrations. The output torque is more uniform under all important operating conditions

allowing a lighter drive train than required for conventional piston engines. The small size

of SYTech engines makes them especially suitable for the more complex packaging

requirements in a hybrid car. The low weight of the engine itself and the lower mass of

components and material required to meet the NVH requirements help to overcome the

inherent weight disadvantage of a complex hybrid system.



APPLICATIONS OF SYTECH ENGINE



CONCLUSION

SYTech engines are smaller, lighter and less noisy. They do not require as much

effort and expense for vibration and noise control and emit less NOx than conventional

engines. Their mechanical efficiency is better, especially at high engine speeds, and they

enable a reduction in vehicle manufacturing costs.



REFERENCES

Theory of machines- R.S. KHURMI

Autospeed.com

Scrbid.com

Dr.Hans. G. Rosenkranz, “ Simple harmonic piston motion of CMCR’s SYTech engines,

influence on design operation”, 10th International Pacific Conference on Automotive

Technology, Melbourne, May 1999.

Dr.Hans. G. Rosenkranz, “What’s different in SYTech engines?”, CMC Research house,

Melbourne, April 2000.

Dr.Hans. G. Rosenkranz, “Why change to CMC Scotch Yoke engine

technology?”,Melbourne, September 1998

Richard P. Gabler, Harry C. Watson, “Experimental investigation of the CMC Scotch Yoke engine linear bearing lubrication system”, SAE Paper 971393, November 1999


Report Sytech Copy

Documents

mahatma gandhi

sobin joseph

unfired test

test rig development

important

free inertia

specific fuel

electrical