POWER TRANSMISSION IN ENGINES

by CHARLES CHINEDU ISIADINSO

  1  

Content

1. UNDERSTANDING THE ENGINE

2

1.1 Choose An Engine To Study 1.2 How Is Fuel Converted To Power

2. HOW IS POWER TRANSMITTED

7

2.1 Transmission Mechanisms (Through The Engine) 2.2 Transmission Mechanisms (Through The Automobile)

3. EFFICIENCY

13

3.1 How is Energy Lost/Wasted 3.2 Compare Performance of Petrol To Diesel Engine

4. THE FUTURE

18

4.1 Compare Performance of Petrol/Diesel To Hybrid Engines 4.2 Effects of Petrol/Diesel Engine On The Environment

5. PRACTICAL SESSION

APPENDIX B

5.1 Disassemble & Reassemble an Engine 6. SOLIDWORKS

APPENDIX C

7. REFERENCES

26

8. GLOSSARY

27

9. APPENDICES

29

  2  

1. UNDERSTANDING THE ENGINE

1.1 Choose An Engine To Study

1.2 How Is Fuel Converted The Power

  3  

1.1 Choose An Engine To Study Before I choose an engine, I would like to take some time to look at the options available. There are a number of ways to classify engines. They are by:

1. Combustion type 2. Fuel used 3. Cooling system 4. Application 5. Construction

1. COMBUSTION TYPE:

In this category there are two types, the external combustion engine (e.g. Steam engines), which, as the name suggests, the combustion process occurs on externally, and the internal combustion engine, which is the common combustion system used in modern automobile engines. We would be considering an internal combustion engine system. Internal combustion engines (IC engines) are further classified by:

2. FUEL USED: IC engines work on a number of different types of fuel (not always in liquid form). These are:

a. Petrol which use petrol or gasoline as their source of energy b. Oils such as diesel oil, mineral oils etc. c. Gaseous fuels e.g. coal gas, natural gas etc. d. Multi fuel. Engines using multi fuels use different fuels for various tasks

e.g. petrol for starting and biogas as the primary fuel

3. COOLING SYSTEM: An engine can be classified by how it is cooled. They are Water cooled and Air cooled engines.

4. APPLICATION: As one would expect, there are different types of engines for different types of machines. This classification varies from Automobile to Aircraft to Marine and home use (e.g. lawn mowers) and earthmoving (e.g. mining equipment)

5. CONSTRUCTION: This category includes Basic engine design (e.g. Rotary, V, Multi-cylinder), operating cycle (e.g. Otto, Atkinson, Dual), working cycle (e.g. two or four stroke cycle), and a lot more but this is not required in my selection process. For simplicity I will be studying a 4 stroke PETROL ENGINE.

  4  

1.2 HOW IS FUEL CONVERTED TO POWER

Work is done, in a petrol (gasoline) engine, by turning the Crankshaft (see Glossary for definitions) a distance of two revolutions (720o) from its start position. This occurs in as many stages as there are strokes. For example, in a 4 stroke engines, the crankshaft is rotated 720o, 2 revolutions, in 4 stages.

Fig 1.

STEP 1 – INTAKE An air-fuel mixture is pulled into the Piston chamber, by the piston, filling the chamber. The mixture enters through and Inlet port which is controlled by an Inlet valve. This process turns the crankshaft 180o.

  5  

Fig 2.1

STEP 2 – COMPRESSION The inlet valve closes and the piston pushes the mixture up the cylinder, compressing it with respect to a compression ratio, for Petrol engines this is usually 1:10 (i.e. the piston compresses the mixture to a tenth of its original volume). This turns the crankshaft a further 180o make a total revolution of 360o.

Fig 2.2

STEP 3 – COMBUSTION The spark plug (or injector in Fig 1) ignites the compressed mixture causing it burn (or combust). The burning gases expand quickly to fill the cylinder. This pushes the piston down to the bottom of the cylinder; this turns the crankshaft a further 180o making a total of 540o from the start position.

  6  

Fig 2.3

STEP 4 – EXHAUST After the combustion, there are some leftover gases, which need to be removed from the cylinder. To do this, the piston moves up, pushing the gases out through a now open Exhaust port. This pulls the crankshaft upwards turning it the final 180o and thus completing the cycle.

Fig 2.4

  7  

2. HOW IS POWER TRANSMITTED

2.1 Transmission Mechanisms (Through The Engine)

2.2 Transmission Mechanisms (Through The Automobile)

  8  

2.1 Transmission Mechanisms (Through The Engine)

How is the recently generated power transmitted through the engine?    Power generated in the engine is transmitted through the engine via the piston-crankshaft connection. All the power generated is immediately transferred out of the engine and as such, there is no power transmission mechanism inside the engine other than the piece of metal, the connecting rod, connecting the piston to the crankshaft.

Fig 3.  

2.2 Transmission Mechanisms (Through The Automobile)

How is the recently generated power transmitted through the automobile? Effectively transmitting power generated in the engine to the wheels in the basic task of an automobile’s (I will be considering a car) transmission system. In the simplest model, the wheels are directly connected to the crankshaft and turn as the crankshaft turns. In modern systems, in order to increase power, the crankshaft is connected to the wheels by a series of gears. The arrangement and shapes of these gears vary between transmission systems. The arrangement of the gears used affect the gear ratio, this in turn affects the power produced by the car. The transmission system connects to the drive shaft, which connects to the differential, which splits power going to the wheels.

  9  

There are two types of transmission systems, the Automatic and the Manual. Both do essentially the same thing but are significantly different. AUTOMATIC:

Fig 4.  The automatic transmission system is made up of a Flywheel, Torque Converter and the Transmission. The flywheel is directly connected to the crankshaft and thus spins with it. The torque converter is connected to the flywheel and is made up of a pump, a turbine and a stator. The torque converter is also filled with a fluid.

Fig 5. As the crankshaft spins, flywheel spins causing the pump, which is directly connected to the torque converter housing, to spin. As the pump spins, it pushes the fluid in the torque converter, the fluid in turn turns the turbine, which turns the transmission. Torque from the crankshaft is thus transferred through the flywheel to the torque converter and finally to the transmission (which goes to the system that drives the wheels).

  10  

Fig 6. An automatic transmission system uses one set of planetary gears (most modern automatic cars have two sets). There is a computer system in the car that chooses the appropriate gears based on the engine speed and the speed of the car. The planetary gear set is made up of five gears: a center (called the sun gear in Fig 6.) gear, three equally sized planet gears and a ring gear. A piece of metal called the Carrier holds the planet gears equidistance from each other. There is no set driven or driving gear(s), thus the system, through a system of clutches, chooses the driving and a driven gears and this creates a gear ratio, which affects the power output which creates the same effect as changing a gear stick in a manual transmission system. MANUAL:

Fig 7.

In the manual system we have a clutch, which is in direct contact with the engine, and a transmission system, which consists of a gear (lets call this G1) on the end of the crankshaft and another gear, G2, in direct contact with G1 (see Fig 9.1). Now there is a rod (called Layshaft) with other gears of different sizes attached to G2 and thus rotate at

  11  

the same speed. So the gears on the layshaft rotate at the speed of the crankshaft. We also have another set of gears on another rod, the output shaft, that sit on top of the gears on the layshaft. The output shaft goes to the transmission system that drives the wheels. The gears on output shaft represent the various gearshifts available to the driver (i.e 1st, 2nd gear etc). The gears on layshaft are in direct contact with the gears on output shaft thus rotate at the same speed. However, the output shaft does not rotate with the output shaft.

Fig 8. Now, in order to get power transferred from the engine to the wheels, the output shaft, which is connected to the transmission, need to rotate. To do this we use a collar called a DOG GEAR. The collar is moved in contact with the appropriate gear (see Fig 9.2) via the gear selector shaft. Once the dog gear is in contact with a gear on the layshaft, the output shaft starts rotating (see Fig 9.3) and the power from the engine is transferred through the transmission system to the wheels (more accurately, the power goes through the transmission to the drive shaft then to the differential which splits the power sent out to the rear wheels).

   

Fig 9.1

  12  

   

     

Fig 9.2        

   

Fig 9.3

  13  

3. EFFICIENCY

3.1 How is Energy Lost/Wasted

3.2 Compare Performance of Petrol To Diesel Engine      

  14  

3.1 How is Energy Lost/Wasted According to the California Energy Commission (CEC), over 60% of energy is wasted by the engine. Energy is lost due to friction, pumping air into the fuel to create the fuel-air mixture that will be burnt in the cylinder and as heat.

Fig 10.

Heat, which, accounts for a significant amount of energy loses in a petrol engine, is the by-product of the compression and expansion strokes. These losses result in a reduction in power and efficiency of about 10% of the power and efficiency of the equivalent fuel-air cycle. This heat is transferred through the engine from the piston fluid. Together with heat, friction is another main cause of energy lose. The petrol engine is made up of numerous moving parts. These parts rub against each other resulting in friction at the boundaries (e.g. between the piston and the cylinder walls). Friction is a source of heat and thus adds to the percentage of energy that is lost as a result of heat. To combat this problem, modern engines are fitted with complicated cooling systems, which, not only reduce the heat lost to the surrounding from the engine, but converts this heat to other useful forms of energy, thus increasing overall efficiency of the engine. Energy is lost in a few other forms. One of these is Idling loss, the CEC this is about 17%. Idling loss is basic energy lost when the vehicle is not moving, i.e. when the engine is producing power that is not being used to move the vehicle. When you stop at a red light, the engine keeps running, burning fuel and turning the crankshaft as usual. However, the gears do not transfer the energy generated to the wheels therefore, it wastes energy generated when the car is idle. To combat this, car manufacturers, such as Peugeot with their e-HDi engine, have created a system that stops the engine when the vehicle is idle and restarts when it needs to move. The system uses batteries to enable the vehicle to restart without lag (for more details visit www.environment.peugeot.co.uk/e-hdi-micro-hybrid-technology/).

  15  

Fig 11. Other sources of energy loss include:

Fig 12.

1. Accessories (2.2%) – Modern vehicles have accessories added to increase comfort, e.g. heating/air conditioning system. These accessories require power to run the power come for the engine making them a source of energy loss.

2. Driveline losses (5.6%) – This refers to the loss in the energy transfer system (i.e. energy lost between the engine and the wheels). There are further moving parts through out the vehicle, moving parts mean friction, friction means energy loss.

3. Aerodynamic Drag (2.6%) – A car does work moving against air. In a

system of moving fluid, the fluid in contact with the body moves at the same speed as the body. This means, a car moving a 50km/hr pulls air around it at 50km/hr. Moving away from the surface of the vehicle, the air molecule at the surface (which are moving at the speed of the vehicle), exert a force on air

  16  

molecules 1 streamline away and those exert a force on molecules a streamline away and so on. This creates a drag, as the force with which the molecules pull reduces with distance from the surface and thus the speed of the air molecules decreases with distance. This drag has a total force acting in the opposite direction to the moving vehicle thus making it a resistive force (or friction). The vehicle has to overcome this in-order to move through the air and the faster the vehicle moves, the greater the force. The more streamline the car, the lower this resistive force and thus less energy is wasted trying to overcome it.

Fig 13.

4. Rolling resistance (4.2%) – When a wheel is loaded, it deflects to form a flat section. This flat section has a resultant force that opposes the forward motion of the wheel. To rotate the tire, the rolling resistance has to be overcome. The rolling resistance is directly proportional to the total weight on the wheels (i.e. weight of the tire + weight supported by the tire), and the length o the contact patch. The greater the rolling resistance, the greater the energy required to over come it and thus the greater the energy wasted.

Fig 14.

5. Overcoming inertia, Braking losses (5.8%) – The vehicle has inertia and

to move it energy has to me lost. How much energy varies directly with the weight of the vehicle.

  17  

3.2 COMPARE PERFORMANCE OF PETROL TO DIESEL ENGINE

There are a number of differences between a gasoline (petrol) and diesel engines. The main difference is the fuel used but there are other slight differences that, along with the fuel, account for the differences in performance. There are a number is ways we could compare these two engines but we will only be looking on the basis of power produced. As mentioned in section 1.2, power in an internal combustion engine is produced in the power (or combustion) stroke. However, in the case of the diesel engine, what happens, in the strokes, is a bit different from the petrol engine.

THE DIESEL CYCLE STEP 1 – INTAKE Air is pulled into the cylinder, via the inlet valve, by the piston. Unlike in the petrol engine where a fuel air mixture is pulled in, here only air is pulled into the cylinder. STEP 2 – COMPRESSION The piston compresses the air. Air is less dense than the air-fuel mixture in the petrol engine therefore the piston is able to compress the air further than the petrol air mixture giving a higher compression ratio (around 1:15). STEP 3 – COMBUSTION The diesel engine does not have a spark plug to ignite the gas; instead the compressed air in the cylinder is at high pressure and thus is at a very high temperature. Diesel is injected into the piston. The heat of the air immediately ignites the diesel causing the combustion required to push the piston down and create the power stroke. STEP 4 – EXHAUST As in the petrol engine, the left over gases are then expelled through the exhaust. Comparing the two cycles, the main difference is the compression ratio. Compression ration is directly related to fuel economy. So diesel engines are more efficient by this standard. However the relationship is not linear so diesel engines do not produce 5 times more energy per cycle but they do produce more than the petrol engine.

   

Fig 15.

Fuel

Eco

nom

y

Compression Ratio

10 15

  18  

4. THE FUTURE

4.1 Compare Performance of Petrol/Diesel To Hybrid Engines

4.2 Effects of Petrol/Diesel Engines On The Environment      

  19  

4.1 COMPARE PERFORMANCE OF PETROL/DIESEL TO HYBRID ENGINES

Before we look into the performance we first need to ask, what is a Hybrid Engine?  Hybrid (hybrid-electric) engines combine the benefits of an internal combustion engine and an electric motor (or motors). Hybrids are an attempt to improve on the internal combustion engine. Different car companies have different takes on what needs improving and how to go about it. There are a number of ways to classify hybrid engines. The more common ones are the gasoline-electric (which uses a petrol engine as its main source of energy) and diesel-electric (which uses diesel as its main source of energy) hybrid engines. Both the gasoline-electric and diesel-electric work in similar ways. The electric motor is used to provide extra power thus reducing the total amount of power the engine itself has to produce. Most hybrids use their electric motors as source of energy in low speed situations thus preventing the burning of fuel required to run the engine. The electric motor is powered by a battery, usually stored in the boot of the car, which needs to be charged, usually by plugging to a power source (series hybrids are fitted with generators, which convert the fuel engine’s power to electricity to charge the batteries).

Fig 16.

  20  

There are two ways of combing the power from the battery and the engine, parallel or series. In a parallel system, both the engine and the electric motor are connected to the transmission system (which drives the wheels). Thus both the electric motor and the engine can provide power to move the vehicle. However, in the series system, power from the engine is converted to electricity in the generator. This is then used to charge the batteries and/or drive the electric motor (which drives the transmission and in turn, the wheels). Thus the main difference is, in the parallel system both the electric motor and the engine can drive the wheels independently but in the series system, only the electric motor can drive the wheels.

Fig 17.

COMPARING PERFORMANCE In most everyday situations, a vehicle’s engine needs no more than about 20 horsepower (HP). However, most fuel engines are capable of producing up to 10 times this amount, why? Vehicles have such high HPs because they are occasionally needed when climbing up and hill or passing another vehicle on the road or accelerating from start to stop. The greater the HP, the bigger and heavier the engine is. However, the car needs the maximum HP only about 1% of the driving time, which means 99% of the time the vehicle is wasting energy carrying an engine that’s too big for its needs. In a hybrid car, the fuel engine is significantly smaller than in a normal car. The engine produces only 10 to 20 horsepower, which is enough to move the car at cruising speed. The battery is used to provide extra energy when needed. When the car is at standstill, the engine keeps running, burning fuel and turning the crankshaft. In a normal diesel or gasoline engine, this energy is wasted as the transmission system is disconnected from the crankshaft and the crankshaft is left to turn aimlessly. In the hybrid system, however, when idle, the engine charges the battery putting otherwise wasted energy to good use. This thus makes the hybrid car much more efficient. However, the hybrid car is carrying more parts; a generator, batteries and a smaller fuel engine in comparison to the normal car, which just carries a larger fuel engine. You could argue the hybrid system is likely to be heavier than the normal system (this is

  21  

usually not the case), but its worth noting much less energy is wasted in the hybrid system and in the odd cases where this is the case, the hybrid system is still more efficient simply because in idle situations, less is wasted. It is also worth noting, that which system is better varies slightly with situation. For example, in a situation where power is of the essence (e.g. climbing steep hills or moving heavy objects), the large HPs of fuel engines is an advantage and most hybrid will not even be able to effectively produce the amount of energy required to complete the task, and thus in this case the fuel engine is the better of the two. But in most everyday situations (e.g. making the school run) the hybrid system would greatly out perform the fuel system.

Fig 18.

  22  

4.2 EFFECTS OF PETROL/DIESEL ENGINE ON THE ENVIROMENT

Petrol and diesel engines have similar but slightly different effects on the environment. We have already established, in section 3.2, that diesel is better (more effective) than petrol. The process of burning petrol and diesel leads to leftover gases being expelled into the atmosphere. These gases contain toxic air contaminants, some of which are carcinogenic to humans. Contaminants of diesel exhaust include:

1. Carbon dioxide 2. Nitrogen oxides 3. Sulfur oxides 4. Hydrocarbons 5. Water

On the other hand petrol exhaust contains:

1. Carbon dioxide 2. Water 3. Nitrogen

On equal horsepower basis, diesel exhaust is 100 times more toxic than petrol exhaust; this is also true when carbon monoxide is considered. Heavily populated places suffer the most as more pressure is put on transport to get people when they need to be quickly and effectively. Over 75% of patients found to have respiratory diseases, in Japan and Europe, where found to have lived close to busy streets and highways for a sustained period of time. CARBON MONOXIDE

Fig 19.1 Fig 19.2 The above charts compare the:

See appendix A for a more complete list of contaminants, how they are formed, their absorption and effects in lung and health effects  

  23  

1. Concentration of carbon monoxide in exhaust gas (Fig 19.1) 2. Carbon monoxide discharged to the atmosphere per hour (Fig 19.2) in gas (propane), diesel and petrol engines when idle, accelerating, cruising and decelerating. Carbon monoxide is an odorless, colorless gas, produced by incomplete burning of petrol and other carbon based fuels (diesel is not a carbon-based fuel). It is also greenhouse gas, which means it stop heat waves from the sun leaving the earth’s atmosphere thus resulting in a raise in the temperature of the planet i.e. global warming. From Fig 19.1 and 19.2, we conclude, diesel is the best of the three with regards to carbon monoxide emission, with petrol being the second best choice and gas being the worst. OXIDES OF NITROGEN

Fig 19.3 Fig 19.4

The above charts compare the: 1. Concentration of oxides of nitrogen in exhaust gas (Fig 19.3) 2. Oxides of nitrogen discharged to the atmosphere per hour (Fig 19.4) in gas, diesel and petrol engines when idle, accelerating, cruising and decelerating. Nitrogen oxide is formed as a result of the oxidation of nitrogen in air (in diesel engine) or fuel-air mixture (in petrol engine) during high temperature combustion processes in the engine. Nitrogen oxides react to form smog, which, in high volumes, causes respiratory problems. Other effects of nitrogen oxide on the environment include: 1. Forms acid rain 2. Contributes to global warming 3. Affects the growth of plants Nitrogen oxide also causes health problems for people as well. Including major respiratory problems, reduced oxygen intake, irritated eyes and/or nose etc.

  24  

When idle and decelerating, diesel, gas and petrol have very low concentration of oxides of nitrogen in the exhaust and as a result, at these times discharge into the atmosphere. This is because oxides of nitrogen form at high temperatures and at idling and deceleration, the temperature of the cylinder is significantly lower than at any other time. When accelerating, diesel has the lowest concentration of oxides of nitrogen but discharges the most to the atmosphere. However, in cruise the concentration of nitrogen oxide is significantly less than in gas and petrol. With the above information, we can conclude diesel in the worst of the three, followed by gas and petrol. FORMALDEHYDE

Fig 19.5 Fig 19.6

The above charts compare the: 1. Concentration of formaldehyde in exhaust gas (Fig 19.5) 2. Formaldehyde discharged to the atmosphere per hour (Fig 19.6)

in gas, diesel and petrol engines when idle, accelerating, cruising and decelerating. Formaldehyde is a colorless, strong-smelling gas, which, on inhalation, can cause bronchitis, coughing, nausea, skin irritation and pneumonia. Aldehydes (Formaldehyde is the simplest member of the Aldehyde group od hydrocarbons) are partially oxidized hydrocarbons in exhaust gas. Formaldehyde is most concentrated in exhaust gas during deceleration in all three engines. And is most discharged by diesel when idle, accelerating and cruising but by gas when decelerating. Petrol, in this case, is the best choice of the three because it discharges the least amount of formaldehyde into the atmosphere in three of the four driving stages. Gas is the next best option as it only discharges more formaldehyde than diesel in the deceleration stage.

  25  

HYDROCARBONS

Fig 19.7 Fig 19.8

The above charts compare the: 1. Concentration of hydrocarbons in exhaust gas (Fig 19.7) 2. Hydrocarbons discharged to the atmosphere per hour (Fig 19.8) in gas, diesel and petrol engines when idle, accelerating, cruising and decelerating. Hydrocarbons refers to a group of compound including: 1. Methane 2. Chlorofluorocarbons (CFCs) 3. Aldehydes 4. Peroxy-Alkyl-Nitrates 5. Aromatic Hydrocarbons 6. Poly-Nuclear Aromatic Compounds The harmful effects of hydrocarbons on the environment and people vary with compound. For example while methane is a greenhouse gas capable of blocking infra-red and heat waves from leaving the earth’s surface thereby causing a heating effect termed global warming, peroxy-alkyl-nitrates cause irritation in the eye. Just like formaldehyde, hydrocarbons are most concentrated in exhaust gas during deceleration. But unlike formaldehyde, hydrocarbons are most discharged by decelerating gas engines. CONCLUSION In conclusion, we can say, while diesel out performs petrol on efficiency; petrol is the safer, more environmentally friendly choice.

  26  

REFERENCES BOOKS:

1. THE INTERNAL - COMBUSTION ENGINE IN THEORY AND PRACTICE – THERMODYNAMIS, FLUID FLOW, PERFORMANCE by Charles Fayette Taylor

 2. STRATIFIED CHARGE AUTOMOTIVE ENGINES – I Mech E CONFRERENCE

PUBLICATIONS 1980-9 Conference sponsored by The Automobile Division of The Institution of Mechanical Engineers, 25-26 November 1980, Institution Headquarters 1 Birdcage Walk Westminster, London

3. 100 YEARS OF MOTORING – AN RAC SOCIAL HISTORY OF THE CAR by Raymond Flower and Michael Wynn Jones

4. BRITISH PISTON AERO-ENGINES AND THEIRF AIRCRAFT by Alec S.C. Lumsden

M.R.Ae.S.

5. AMERICAN HORSEPOWER – 100 YEARS OF GREAT CAR ENGINES by Mike Mueller  

6. THE COMPOSITION OF EXHAUST GASES FROM DIESEL, GASOLINE AND PROPANE POWERE MOTOR COACHES – JOURNAL OF THE AIR POLLUTION CONTROL

ASSOCIATION by Martin A. Elliott, Gerge J. Nebel & Fred G. Rounds (1955) WEBLINKS:

1. cecs.wright.edu/~mawasha/Chapter 1 Class Notes.pdf 2. web.iitd.ac.in/~ravimr/courses/mel345/classification.pdf 3. enginemechanics.tpub.com/14037/css/14037_96.htm 4. www.autoeducation.com/autoshop101/engine.htm 5. www.consumerenergycenter.org/transportation/consumer_tips/vehicle_energy_losses.html 6. www.tpub.com/eqopbas/3.htm 7. www.motorera.com/dictionary/ 8. www.environment.peugeot.co.uk/e-hdi-micro-hybrid-technology/ 9. web.mit.edu/sloan-auto-lab/research/beforeh2/otr2035/ 10. www.fueleconomy.gov/ 11. www.jabfm.org 12. www.theguardian.com/uk/2013/jan/27/diesel-engine-fumes-worse-petrol

IMAGES:

1. www.uefap.com/vocab/learn/meaning.htm 2. www.tpub.com/eqopbas/3.htm 3. raanz.org.nz/wiki/pmwiki.php?n=TM.Technical 4. www.bankspower.com/techarticles/show/9-Understanding-Torque-Converters 5. geekmecca.com/innovations-in-driving-the-automatic-transmission/ 6. mechanote.blogspot.co.uk/ 7. www.carbibles.com/transmission_bible.html 8. www.motorera.com/dictionary/ma.htm 9. www.mustangmonthly.com/howto/mump_0903_mustang_top_loader_transmission_rebuild/ph

oto_03.html 10. www.consumerenergycenter.org/transportation/consumer_tips/vehicle_energy_losses.html 11. www.sankey-diagrams.com/tag/energy-loss/page/2/ 12. people.oregonstate.edu/~warnersa/research_phd.html 13. flocycling.blogspot.co.uk/2011/08/flo-cycling-component-series-part-4-flo.html 14. vehicleshybrid.blogspot.co.uk 15. auto.howstuffworks.com/fuel-efficiency/vehicles/question262.htm

  27  

GLOSSARY 1. Crankshaft – a long metal rod, used to turn the wheels

2. Inlet port – the opening from which the air and fuel mixture enters the cylinder 3. Inlet valve – a plate located where the inlet port meets the cylinder. It is used to close the inlet

opening during the compression to exhaust stroke 4. Spark plug – a device in an engine that produces an electrical spark that lights the fuel

5. Exhaust valve – the opening from which leftover gases leave the cylinder 6. Piston – is a cylindrical piece of metal the move up and down inside the cylinder

7. Flywheel – A relatively large and heavy metal wheel that is attached to the back of the

crankshaft to smooth out the firing impulses. 8. Torque Converter – A unit in an automatic transmission which is quite similar to the fluid

coupling that transfers engine torque to the transmission input shaft. 9. Drive shaft - The shaft connecting the transmission Output shaft to the differential pinion

shaft. It transmits power from the transmission to the differential.

  28  

10. Pinion shaft - A short drive shaft in the rear axle connecting the prop shaft to the crown

wheel via the final drive pinion

11. Generator - An Electromagnetic device for producing Direct current electricity. 12. Horsepower - (HP) A measurement of the engine's ability to perform work. One horsepower

is defined as the ability to lift 33,000 pounds one foot in one minute. To find horsepower, the total rate of work in foot-pounds accomplished is divided by 33,000. If a machine were lifting 100 pounds 660 feet per minute, its total rate of work would be 66,000 foot pounds per minute. Divide this by 33,000 foot pounds per minute to arrive at 2 horsepower. In metric terms, it is the ability to raise 250 kilograms a distance of 30 centimeters in one second. It is also equal to 745.7 watts.

  29  

9. APPENDICES

  30  

APPENDIX A