Automobile Engineering ral ‘Technical Series 2022 AUTOMOBILE ENGINEERING Q.1 Choose the correct answer of the following: (Answer any seven) (a) The power to weight ratio of diesel engine compared to petrol engine: (i) High 1- (i) Low Gii) Same (iv) Not comparable Ans. (ii) (b) A universal joint allows the ‘propellor shaft to (i) Change inclination. (ii). Change length Gii) Bend side ways (iv)Transfer torque at an angle Ans.(iv) (c) Camber should generally lie in the range (1) Less than 1 degree (ii) Between land 2 degree (iii)Between 2 and 4 degree (iv)Around 7 to 8 degree. Ans.(ii) g ; (d) The torque converter uses to transfer torque. (@) Air ‘ (ii)Automatic transmission fluid (ATF) (ii) Gears 3 (iv) Steel belt Ans. (ii) (c) The function of anti-lock brake system (ABS) is that is (i), Reduce the stopping distance : (ji) Minimise the brake fade ii) Maintains directional control during braking t the wheels from locking é (iv) Prevents nose dive during braking and there tpones locking of the wheels : Ans. (iii) © scanned with OKEN ScannerAutomobile Engines ne 7 ‘Technical Series (8 The component hat connects the steering rack to the knuckles is @) Tierod ) Sector gear Gi) Pivot Gv) Spline Ans.() (@ The process of supplying the intake air to the engine cylinder at a density greater than the density ofthe surrounding atmosphere is known as @) Supercharging (iii) Polymerization Ans.) “th) Ina single dry plate clutch, torsional vibrations are absorbed by {i Coil springs known as torsional springs (ii) Cushion springs. (ii) Central hub (v) Clutch pedal Ans.(ii) u) The chassis in which engine is mounted completely inside the driver's cabin is called G) Conventional control chassis (ii) Semi-forward control chassis (i) Fullforward control chassis (iv) None of the above Ans. (iii) G) The aspect ratio (expressed in percentage) of the tyre is defined as the ratio of (i) Section height to section width Gi) Wheel diameter to section height (ii) Wheel diameter to section width (iv) Section width to section height Ans.(i) re Q.2.(a) What is common rail direct injection-(CRDI) system? How is it different from conventional injection syste™? ‘Ans Common Rail Direct Injection (CRDI) is a modera fuel injection system used in diesel engines. It offers several advantages Ve? conventional injection systems, including improved fue! i) Scavenging Gv) Detonation LK. CULTS Automobile Engineering (31 ‘Technical Series cllicieney, lower emissions, and better performance. « Here's how it works: 1. High-pressure fuel pump: The CRDI system uses a high- 1 very high levels, typically pressure pump to pressurize the fuel t around 2,000 bar (29,000 psi). 2, Common rail: The pressurized fuel is then stored in a common rail, which is a high-pressure pipe that runs along the engine. 3. Injectors: Each cylinder in the engine has its own injector, which i electronically controlled. The injectors receive fuel from the common rail and spray it directly into the combustion chamber at the precise timing and quantity needed. Advantages of CRDI over conventional injection systems: + Precise control: The electronic control of the injectors allows fow much more precise control of the fuel injection timing and quantity. This leads to better combustion, which in turnimproves fuel efficiency and reduces emissions. + Multiple injections: Unlike conventional systems, CRDI systems can perform multipie injections per eyele. This can further improve combustion and reduce emissions, igher pressure: The high pressure of the fuel in the common i allows for better atomization of the fuel. which means it burns more efficiently + Quietet operation: CRDI engines are generally quieter than conventional diesel engines. Conventional injection systems: In contrast to CRDI systems, conventional diesel injection systems use a separate pump and injector for each cylinder. ‘The pump pressurizes the fuel for each injection event, and the injector sprays the fuel ditectly into the combustion chamber. Disadvantages of conventional injection systems: + Less precise control of injection timing and quantity + Nomultiple injections + Lower fuel presstire, leading to less efficient combustion + Noisier operation Overall, CRDI is a more advanced and efficient fuel injection ayatem than conventional systems. Itoffers a number of benefits, @ scanned with OKEN ScannerBoth transistor-based coil (TCI) and enpacitive discharge (ODI) ignition systems are electronic alternatives to the older breaker. point systems in spark-ignition engines, However, they operate in fundamentally different way i Transistor-based Coil Ignition System (TCI): Operation: Uses a transistor as a switch to control the eurrent flow to the ignition coil ~ When the trigger signal arrives (from crankshaft sensor), the transistor switches "on," allowing battery current to flow through the primary winding of the coil. + This builds up-a magnetic field in the coil. + When the transistor switches "off" abruptly. the collapsing magnetic field induces a high voltage in the secondary winding of the coil! ‘This high voltage creates the spark at the spark plug. Energy source: Uses directly from tho battery. p Coil type: Uses a conventional ignition coil with high inductance for building up a strong magnetic field: Spark characteristics: Delivers a relatively long-duration spark. Advantages: Simple, reliable, cost-effective, works well at low engine speeds. 3 Disadvantages: Can suffer from voltage drop at high engine speeds, leading to weaker apark. Not as powerful as CDI for high-performance applications. Capacitive Discharge Ignition System (CDI): Operation: + — Stores electrical energy in a capacitor. + Acharging circuit builds up the voltage in the cai acitor. | = the discharge circuit allows “through the ignition coil vo igh + ‘Thiw rapid discharge creates a very bi the accondary winding of the coil, generating a powerful spark + Eneray source: Initially depends on battery for charging, but the capacitor itself provides the spark energy. + Coil type: Uses a low-inductance ignition coil for fast energy voltage spike in transfer from the capacitor. + Spark characteristics: Delivers a very short, hot, and intense spark, + Advantages: Powerful spark at all engine speeds, improves combustion efficiency, reduces emissions, better suited for high- performance applications, + Disadvantages: More complex and expensive than TCI, can be sensitive to electrical system problems. Q.3.(a) Sketch and explain the working of an electromagnetic clutch in an automobile. { Ans. Plectromagnetic Clutch: A Magnetic Matchmaker in Your Car A peek into the world of electromagnetic clutches, the silent and smooth operators behind seamless gear changes in modern Sketching the Scene: Imagine a two-piece stage: + Rotor: A metal disc attached to the engine flywheel, constantly spinning with the engine. Armature: Another metal disc, connected to the gearbox input shaft, waiting patiently for its cue. Between them lies a narrow air gap, filled with the invisible ‘magic of electromagnetism. > The Grand Act: 1, Step on the Gas: When you press the clutch pedal, an electric Current surges through a coil wrapped-around the rotor. . Magnetic Mojo: The coil transforms generating a powerful magnetic field. into an electromagnet, @ scanned with OKEN ScannerAutomobile 161 inecring “Technienl Sorien | Automobile Engineering (7) ‘Technical Series 8. Attraction Tales Hola: The magnetic fatapullsdvenmHatire | ay wards the war, bridging the nit Bap. 1, Friction TAR Ose ae bee faless Goubie ficiee bath + Paster Response: Quicker engagement means less lag between like ¢wo hands firmly elaeped. ee Ge 1 pressing the pedal and power reaching the wheels. 5, Power Play: The engine's rotational force i now tranafereg}_ ” Redeed Wear and Tear: laws frition means less wear on : snow transferre iced V ined eceariey from the rotor tothe irmature, spinning the gearbox inp the clutch components, leading to lenge eee ee ee wthe gearbox input shaft], Peegise Control: Electronic control ofthe clutch coil allows for Release the Stage: fne-tning of engnsement and diengarement ideal for he Pedal: When you lift your foot, the curren automated gearboxes. * ead ee Pedal: When you lift your foot, the current tothe} 6, the next time you effortlessly shift gears in your car, cases remember the quiet work of the,clectromagnetic clutch, the 2, Magnetic Fade: The electromagnet loses its grip, themasnet| visible conductor orchestrating the smooth flow of power. fiold weakens : (b) Sketch and explain the working of synchromesh gearbox.. 8, Spring Back: Powerful springs behind the armature push if Ans Synchromesh Gearbox: Smooth Shifts, away from the rotor, widening the air gap. ‘The rumble and grind of clunky gear changes are a thing of the 4 Friction Fides: With the dises apart, friction disappears, and <= - to Engine Serew nut Pa ‘ = Flywheel . i ‘ Benefits of the Magnetic NE es Goa tningtl Smoother Gear Changes: No eamant the power cumnection between engine and gearbox breaks, Cluteh \ ¥ Serew shaft thanks to the gradual engagement and disenga past thanks to thé ingenious invention of the synchromesh gearbox. But how does this magic box behind the scenes ‘transform gear shifts intoan effortless ballet of power? The world of gears and friction with sketch and explanation: ) ‘The Stage: Imagine a three-tiered platform where the'gears play the @ scanned with OKEN ScannerUe so} oatns exouste9q "YBN. ey ATGoANp pure AmquTOX On THU weyshs oxp Jo 2900 at SuTDUETEG :ArNHIGUITOY PUY 3809 * “suoqvo0xp q poumaun Surztunune pus uonsnaian duran do 4q Simp 02 omqtUoD or spaou waysKs uoRNAsr oUy, “sUOJesTWHO Suronpax ezytiotd sourua usopoyy :Joryuog suojssyury “suonpitea Toyuotauostats asa%p 20j ozvetiodoo on poUdisap 04 PINOYS wiarsAe ayy, “asuEITAOpI0d BjINds ay ioaye ULD apne pu ‘eyypramy ‘amerederay,:exo.9v PoUOMUOLAWY * -uonssnquro 3wo!gF9 £05 s10198) aso4p Aapisti9 or spaou usisep ati, uoneSedozd pure sunt y.0ds yp ouaNg JO opow o4,S0up jeLIOIwM a pire soponoa[o nyd y20ds aya ‘uoona0g do ayy, spuHT03U]y opor}oaig pv dep Smjg yrvdg + -suontpuoo je xepan sBrous pur Sun yzeds aswoard Suyoatyap sq sasuey> osayp 03 adupe ysnun way9%s uomudt ou, “speo] pur spaods jo aBuer v ssoise ayviedo soutiug :suonypuog Sunwiedg ousug « any was0yo 247 10) SBa9ua yreds syeridosdde aya exaarjap wrays4s ay) aunsuo yentu s0uSts9p aug, Josep oy paredwio loys ysnory toaod SunymsuE ‘urAeAtIp amp oF auLAUD ax, | yoauuooas ypanyo ayy ‘pasesiuo sxead ays YEN -AOysUUIY, 19MOg -soxpiodiog wou} Bu/90] “43903 008 ay XoA0 aprTS Stkpooms AS ay puR ‘sosva LOIN, aty ‘azuOLyaUAS sqnog Suryoreyy ‘spoads Suryouey Sunoopes anos avah yeys lumi oy) Jo paads aya yoreut oy xe98 ayeyscey Surunds oxy uMOP ends sugy,‘sonaey SuReAN ‘reo8 ypeyso] ow Yat eIG0D Ore atuoo sButt Joztuompuds ayy, oBUg 103N9D SoxY], WOOT “youscoy ay Uo wok Suspuodsaxtos ay spre0r sSurz rezmonpuss oy Surysnd ‘xeT]oo ayy saBeBua stu, 1902] av08 oy Sutadiu N2+2C02 ‘This reaction removes harmful NOX, a major contributor to nei rain and smog. 4. Oxidation Reactions: Inthe second stage, CO and HC are oxidized to harmless carbo dioxide (CO2) and water vapor (20) by platinum and palladiy catalysts: 2C0 +0, > 2C0, CsHy + («+ y/2)0, —> xCO, + y/2H,0 ‘Thece reactions eliminate toxic CO sind unburned hydrocarbo reducing air pollution and improving air quality, 5. Clean Exhaust: ‘The cleaned exhaust gases, consisting mainly of CO2, H20, a N._ exit the converter through the outlet pipe and are relen into the atmosphere. Diagram: a = th shite ate Lakin eaneater cou wna eaten Factors Affecting Performance: + Temperature: The converter needs to reach a certain oper™ temperature (around 250°C) for optimal performance. Cold and short trips can hinder its effectiveness. ‘Technical Serica| ‘Technical Series Fuel Quality: Using low-quality fucl or fuel additives can contaminate the catalyst and reduce its efficiency: |. Sensor and Control Systems: Modern vebiclrs use sensors ae rontrol eyateme to monitor the exhaust temperature and adjust fuel delivery to optimize converter performance. Benefits of 3-Way ¢ atulytic Converters: |. Reduced Emissions: Significantly reduces harmful pollutants like NOx, CO, and HC, contributing to cleaner air and improved public health, Z +. Environmental Protection: Helps mitigate the effects of acid rain, smog formation, and climate change. + Improved Engine Efficiency: Can optimize fuel combustion and engine performance in some cases. Overall, 3-way catalytic converters are essential components of modern vehicles, playing a crucial role in reducing harmful emissions and protecting the environment. Understanding their working principle and the factors affecting their performance is essential for maintaining optimal air quality and promoting sustainable transportation. : 7 (a) Explain the use of lubricating system and its part in automobile engine. .s. The lubricating system in an automobile engine is a critical component responsible for minimizing friction and wear between ‘moving parts, ensuring smooth operation and extending engine life. Here's an explanation of its role and main parts: Importance of Lubrication: Engines consist of numerous moving parts like pistons, connecting rods, crankshaft, and bearings. These parts constantly rub against each other, generating friction and heat, Friction can lead to: Increased wear and tear on engine components, leading to premature failure, Decreased engine efficiency due to energy lost overcoming friction. Overheating and potential engine damage, @ scanned with OKEN ScannerAutomol ngineering [18] Tole of the Lubricating Syst jeating system addresses thes f ppery’ ana wear, Removes heat: Hot engine cil, carrying it away to the oil cooler for dissipation. Cleans and protects: Oil trapssiall debris and contaming generated during engine operation, preventing them f causing damage. Additionally, it coats metal surfaces, protectins, them from corrosion. ‘Main Parts of the Lubricating System: Oil sump: Reservoir for storing the entire engine cil: «Oil pump: Picks up oil from the. sump and circulates it un pressure throughout the engine. 3 Oil filter: Removes dirt, metal particles, and other contami from the circulating oil. + Oil pressure gauge: Monitors oil pressure, alerting the to potential system failures. + Oilchannels and passages: Network of smalll passages the engine block and components to direct oil flow to et areas. : ‘Types of Lubricating Svsteins: a + Splash lubrication: Older and simpler engines re eplashing oil thrown by the crankshaft to lubricate parts + Pressure lubrication: Most modern engines use a pus directly deliver oil under pressure to all essential comp Maintaini: icatins a + Regular oil changes are crucial for maintaining °P! lubrication performance, Dirty or old oil loses its viseo#! effectiveness, increasing friction and wea, Using the correct oil type recommended by the may" | ¢nsures proper lubrication for specific engine require Monitoring oil level and pressure through gause® #8 | detecting potengial leaks or system imalfunctions. pin: b) A 4-stroki 6 jsplacement 5200 cc develops 1 mes 33 ke of petrohr of the calorific v (kg at 3000 r.p.m., find- Compression ra ‘Totat piston dis Brake horsepo » (CR) = 65:1 nt (Ve) (BHP) = 135 BHP Fuel consumption (FC) = 33 ke/hr Caloritic value of fuel (CV) = 10,560 kealikg * Speed (N} = 3000 rpm Volumetric efficiency (nv) = 8 Speci Press volume of petrol vapor (v) = re (P) = 1.08822 kgfiem? Temperature (T) = 15°C. Gas constant (R) = 29.27 kgtlkg-K. Specific heat ratio of air (7) =A To find: (i) Braké mean effective pressure (BMEP) (ii) Brake thermal efficiency (1th) (ii) Air standard efficieney (as) iv) Air-to-fuel ratio (A/F ratio) by weight lution: 7 Brake Mean Effective Pressure (BMEP): , Conyert BHP to kW: BHP x 0.746 kW/BHP = 135 BHP x 0.746 kW/BHP = 100.71 kW. Calculate stroke volume (Vs): Vd'/ number of cylinders = 5200ee/4= 1900 cq: Convert Vs tam*; 1300 ce x (1. m°/1000 ee) = 1.3. m* © scanned with OKEN Scannershi Baines * calculate fuel flow rate mf: FC x (1 W360 9) Eee 3 keflr x (1 1/9600 #) = 0.0092 kis: rae oma ma ATE 7 srk per eyele (We): Automobile Engineering (24) Technical Series 118.1 kPa Caleulate Naw: = (LCR y 1-0/6.5""") = 61.9% 4. Air-to-Fuel Ratio (A/F ratio): Rearrange ma = mf/ AF: AF = mf/ ma Substitute ma and solve for A/F: A/F = 0.0092 kg/s / Calculate ait Convert brake power to wot BHP x 20N/60 = 100.71 RW x 270 * 3000 rpm / 60 = anit Nmifeyele (ewe): Ve x NY Define swept volume mx 08 “ot m? {.8 (a) Discuss the necessity of using a thermostat valve in Wer Vaweep the engine cooling system. Explain the construction and Calculate BMEP: We working of any type of thermostat valve. 141.4 Nmley = 020 kPa ermal Efficiency (11th): 2 ae ee soi wae CX CV x 1000 kd /keal = 10.560 kcal/kg * 1000 kcal 10.560 kJ/kg Calculate lower calorific value (LCV): GCV » (1 ~ humidity ratio) = GCV (assuming negligible humidity) <= 10,560 kk, Calculate brake power in kis BHP x 0.746 kW/BHP 1 kdfs/kW = 75.01 kus 7 Calculate nth: brake power / (mfx LCV) . « ; = 75.01 kills ( (0.0092 kg/s * 10,560 kis)» = 78.1% 3, Air Standard Efficiency (")as): g Caleulatgaverage pressure during expansion stroke Pa ns. Necessity of Thermostat Valve in Engine Cooling System: A thermostat valve is a crucial component in a vehicle's engine cooling system due to its role in: Maintaining Optimal Engine Temperature: + Engines operate efficiently within a specific temperature range ‘Too cold, and fuel burns inefficiently, increasing emissionsand wear. Too hot, and engine damage can occur [The thermostat regulates coolant flow, allowing the engine to Quickly reach its ideal operating temperature nd maintain it _] by Preventing excessive cooling at higher loads, } Redoced Era ions and Fuel Consumption: See ae Pollutants due to incomplete ly warming up the engine, helps reduce harmful emissions. Efficient engine operation al better fuel economy, _}- Engine Protection Caleulate gro: the thermostat * t consistent temperatures leads to , Pix (cry? avoidiy eating by controlling coolai woiding extreme engine int flow and ~ 1.08322 kegflem* * 6.5)" Improved Cabin Heating ae = 4.09 kelem’ © + | Incold weather, the thermostat restticta coolest Convert Paverage to Pa: engine is warm, directing additional Rego et UO Until the utional heat to | Providing faster and more efficient eabic warminy Providing faster it E. Construction and Work: ng of a Wax-Pellet Thermostat. ras 0 4.09 kgflem? x (101.325 kPa/kgflem) @ scanned with OKEN ScannerAutomobile Engineering vais a common type of thermostat, utilizing a temperatuy (23) hia -aching the engine components. This | circulating oils filtered, removing contaminant the oil filter first before 1 sensitive wax pellet: ensures that Constructio! omy ember contains a wx pellet and a spring-ondl_ Pefore they eon cnute damage ee Merits: High filtration efficiency: Excellent at removing even fine particles due to «il oil passing through the filter. Reduced wear and tear: Provides maxintum protection for engine components. «The wax pellet expands significantly with inereag contracts when cold, temperature and c the flow of coolant between the engine + The valve controls the radiator. ‘Sim i oF pple design: Easier to maintain and diagnose issu Working: Diagram paar «+ Doving a cold start, the wax pellet is contracted, and the pr keeps the valve closed. Coolant circulates only within thee allowing it to warm up quickly. «.Asthe engine heats up, the wax pellet expands, pushing agai the spring and gradually opening the valve, 1 + More coolant flows to the radiator, wheret is cooled by. airflow. : «When the engine reaches its optimal temperature, the ‘opens fully, allowing all eoolant to flow through the radial tiaintaining a stable temperature. «Ifthe engine temperature starts to rise again due to in Joad, the wax pellet expands further, opening | ‘the valve wit increase coolant flow and cool the engine Benefits of Wax-Pellet Thermostats: + Reliable and cost-effective is + Relatively simple construction and operation + Quick response to temperature changes ‘ (b) Explain briefly full flow and partial flow Iubric system with diagram Indicate their merits. ‘Ans. Full Fiow and Partial Flow Lubricating Systems: Lubricating systems play a crucial role in reducing friction Demerits: wear in engine components, They achieve this by circulalit Higher oil pressure requirements: Requit (sca arene creatingn thn botween moving Pa MPUPP Lo orercome the pronte dap em toe ee are two main types of lubricating systems: *tentially slower engine warmuy vara, by the filter. the iter, delaying eartae ms sk oil flow cari be restricted nereated itor clogging: Filters can clog fate due to hanaling @ scanned with OKEN ScannerAutomobile Engineering all the oil Partial Flow Lubricating System: Function: Only a portion of the oil pumped by the oil pui goes through the oil filter. The remaining oil bypasses the fil sand directly lubricates the engine components through a byp, valve. Merits: Faster engine warmup: Less oil flow restriction allows for fas engine warmup. Reduced oil pump pressure requirements: Requires a | powerful oil pump compared to a full-flow system. Extended filter life: Filters clog less frequently as they han less oil Demerits: Lower filtration efficiency: Only a portion of the oil is filte potentially allowing some contaminants to circulate, Increased wear and tear: Engine components may be exp to unfiltered oil, leading to potential wear. More complex design: Requires a bypass valve and additiot oil passages, making it slightly more complex. 9 (a) What is biodiesel? Explain various processes invoi in transesterification process to convert vegetable oil i biodiesel. Ans. Biodiesel: A Sustainable Fuel Alternative Biodiesel is a renewable and environmentally friendly derived from vegetable oils or animal fats. It can be use unmodified diesel engines, offering a cleaner and lower-emi alternative to traditional petroleum-based diesel. ‘The Transesterification Process: Converting vegetable oil to biodiesel involves a chemical rea called transesterification. This process separates the fatty chains from the glycerol backbone of the triglyceride mol in the oil, converting them into fatty acid methyl esters (F also known as biodiesel. Here are the main steps involved: 1. Pre-treatment: ‘ + ‘The vegetable oil is filtered and dried to remove impurities! and suspended solids that can interfere with the reaction. Depending on the oil type, additicnal steps like degumming and acid neuts tion may be required. 2. Reaction: 3 + The oil is mixed with an alcohol (typically methanol or ethanol) and a catalyst (usually sodium hydroxide or potassium hydroxide). + The catalyst triggers the transesterification reaction, breaking the triglyceride molecules and forming FAME and glycerol. + ‘The reaction temperature and duration depend on the specific oil and catalyst used. 3. Separation: + The reaction mixture forms two distinct layers: FAME on top and glycerol at the bottom due to their different densities. + Centrifugation or gravity separation techniques are used to separate the layers. 4. Washing and Neutralization: * The FAME is washed with water to remove traces of catalyst, soap, and other impurities. ay * The pH of the washed FAME is adjusted to neutral using an acid, like citric acid, to prevent corrosion and ensure fuel stability. * 5. Drying and Filtration: ° + The FAME is dried to remove.any remaining water, which can affect its combustion properties. + Finally, the FAME is filtered to remove any final impurities before storage or use. Advantages of Biodiesel: + Renewable resource: Derived from phint-based oils, a readily available and renewable resource. ics + Reduced emissions: Emits significantly less greenhouse gases and pollutants compared to petroleum diesel. + Improved air quality: Hel : : ps ‘reduce smog and improve ai quality, especially in urban areas, aes + Biodegradable and non-toxic: Less harmful to the environment if spilled compared to petroleum diesel. © scanned with OKEN ScannerAutomobile Engineering 26) + Supports energy independence: Reduc and promotes domestic fuel production. Challenges of Biodiesel: + Higher production cost: Currently, biodiesel production costs are often higher than petroleum diese! + Land use concerns: Large-scale production can compete with! food crops for land use. + Cold weather performance: Some biodiesel blends may have poorer cold flow properties than straight diesel ‘(b) What are hybrid vehicles? With the help of a schematic} diagram, explain the working of any hybrid electric auto vehicle. . 4 Ans. Hybrid Vehicles: Blending Power for Efficiency Hybrid vehicles are a type of electric vehicle that combines an internal combustion engine (ICE) with an electric motot an battery, offering improved fuel efficiency and emissions reductol compared to traditional gasoline-powered cars. Here's breakdown of their workings, along with a schematic disgran for better understanding: ‘Schematic Diagram of a Full Hybrid Electric Vehicle (HEV): ams ¢ Technical Series assists the ICE provides limited electric driving Full Hybrid (HEV): The electric motor can power the vehicle for short distances without the ICE running. offering significant fuel savings. Plug-in Hybrid Electric Vehicle (PHEV): Can be charged from an external eource. offering extended electric driving range and lower overall emissions. Working Principle: . Starting and Low-Speed Driving: The electric motor draws power from the battery to propel the vehicle for short distances reducing reliance on the ICE and emissions. . Acceleration and Highway Cruising: The ICE takes over for higher speeds and highway driving, with the electric motor assisting during acceleration for imptoved @fficiency. + . Regenerative Braking: When braking, the electric motor acts as a generator, converting kinetic energy into electricity to recharge the battery. . Idle Stop-Start: The [CE automatically shits off when the vehicle stopsat a traffic light orn heavy traffic, further reducing fuel consumption and emissions, i Benefits of Hybrid Vehicles: _ Improved Fuel Economy: Hybrids offer significantly better fuel economy compared to traditional gasoline-powered cars, reducing fuel costs and environmental impact. , Reduced Emissions: Hybrids emit less greenhouse gases and pollutants, contributing to cleaner air and mitigating climate change. ‘ Smoother and Quieter Operation: The electric motor provides a smoother and quieter driving experience, especially © scanned with OKEN ScannerOperation Resoarcl 2 214) ‘Technical nical Series Now, 1 Average waiting time in syste “yk lable. In good weather go-35 = 60-20 = 40 S- aff Challenge: jd Vehicles: “4 vehicles generally have a hig cars due to the ad .s of Hybri itial Cost: Hybri an gasoline-powered =1.5 min. Ans. (ii) Avg. Service time =|*x— B*p-3 a ® = & _ Full bybsids have Limited ce the ICE. t (@ Avg. waiting tinie in __ = 18 min (God weather) ie Gi) Average waiting time a fo min (Bad weather) OA minutes (geod Seber) = 4 min (in Bad weather) Ans. + Limited Elect driving range, Te Battery Degradatio affecting its capacity and gene EEE performance. a If You Have any Idea or any New concept Kindly concerened with publication © scanned with OKEN Scanner——$—$—$ ing (215) ering (216) ‘Technical Series away from the vertical, when viewed from the front of car is called (i toe in 2021 (i) caster Gi) camber (iv) toe out Answers : (iii) (The torque converter uses to transfer torque. air Gi) automatic transmission fluid (ATF) seven} : Gi) gears (@) Ford EcoSport 2021 model has Sng Gs) steel belt @ manual transmission Sn Anéwers Gi) semi-automatic transmission (ii) fully-automatic transmission Gy) Both () and Gil) Answers : (i) . (&) Ina square type engine Le @ geometrical shape is square” Gi) diameter and length of piston are same (®) The starter motor is driven by -@ chain drive Gi) Nat belt drive Answers (ii) gear drive Gy) Vebel€ drive (b) The aspect ratio (expressed ‘it-percentage) of the tyre is defined as the ratio of @) section height to section width (i) wheel diameter to section’height (ii) wheel diameter to see (Gi) two cylinders are placéa horizontal and two vertical (iv) stroke length and cylinder bore are same Answers : (iv) me (©) The connecting rods) cross-section,» ion width Ge) section width to section height 2 Answers : (j) ‘Ceca @) In radial tyres ‘ @ one-play layer’ runs dia, | Or - layer run GL pi, Gi) all plies rai Answers : (i), Bn : i ead | (@) The vehicle ride will be comfortable if Gii) inner tubes are always used : | @ widprimg waseiadiage feline G) None ofthe above Gi) sprung mass is kept minimum mail a (iii) vehicle mass is kept minimum (iv) All of the above Answers* (i) 3 WHO The: caster is cal Ned positive whe in i inden ae ren the top of the pin is @ scanned with OKEN Scannernical Serie) Automobile Engineéring [218] ‘Technical Series Automobile Engineering [217] left of the vehicle (iv) right of the vehicle Answers : (i) rk differe 2. (a) With the help of neat sketch, mai iss 8 components of a 4-wheeler, 2 rear wheel-driven ct Ans. Gearbox , Longitudinal engine“ 3. 8 Dire 3| bool : é sar of the vehicle shaft front engine rear wheel drive layout diagram In this layout, front mounted engine-clutch-gear box u drives a beam typé'of rear axle suspended on leaf 5 through a propeller shaft with two universal joints. Wi help of coil springs, tho, front wheels are independent sprung. 3 The rear-wheel “dtive vehicle layout is a configurat which the engineidrives the rear wheels of the vel transferring the power generated to rear whee vehicles use éeyeral components such asa drive shaft. and differential. The drive shaft is also known as a propel differential and rear wheels. In comparison with the icle drives such as the front-wheel and four-wheel imple from a design and packat In addition, many engineers believe that rear-wheel drive (RWD) arrangement is more suitable for performance vehicles that employ engines of high power output. Possible configurations in rear-wheel drive layout: ‘According tothe postion of engine and gearbox, RWD layout can have the following arrangements: Front mounted engine with rear-wheel drive ‘Mid-mounted engine with rear wheel drive Rear-mounted engine with rear wheel drive ‘Among the above-mentioned arrangements, ‘front-mounted engine with rear-wheel drive’ is the most popular in the automotive industry. There are two.main reasons for this. Firstly, mounting the engine in front of the vehicle simplifies’ the layout by leaving ample.space’ for other systems. Secondly, it helps to achieve better weight distribution (heavy engine at one end while other heavy components at another end) of the vehicle. Q 2. (b) Distinguish between an articulated vehicle and a rigid vehicle. How do'their construction and design differ from each other? ‘The primary difference between an articulated dump truck and a rigid dump truck has to do with the frame. In a rigid dump truck, the cab/and dump body both sit on the same fixed chassis. In an articulated dump truck, on the other hhand, the cab attaches to the tipping body at a point of directly behind the cab. This design gives articulated dump trucks greater flexibility, allowing them to pivot at the articulation point. Articulated dump trucks also provide increased traction and better performance on steep grades compared to rigid models, Rigid dump trucks, also known as rigid haulers or tipper trucks, allow you to transport large quantities of abrasive © scanned with OKEN ScannerAutomobile Engineering [219] Technical Ser materials and rocks. This high capacity is ideal for jg hauls across flat ten‘fin, particularly quarries and mined They have a fixed chassis that the cab and dump body sig As a result, the stecring is based on a traditional systeq called rack-and-pinion steering, meaning they are reas! wheel-drive. A rigid hauler is best suited to inclines of 154 or less but have a job life of a minimum of five years due tg their ability to hold such a high capacity of materials. Compared to the rigid dump truck, the articulated dump/tipper truck can handle rough and unruly terrain and weather, along with lower ceiling heights, restricted turning radiuses and narrow roads. This dump truck's cab and reas dump meet at an articulation point that is situated directly} behind the cab. This articulation point controls the ability of the truck to pivot and is also known a8 articulated steering allowing the truck to be easily maneuvered. It also is eapable of keeping all six wheels on the ground through it oscillating and articulated hitch, capable of working on 35% incline due to the haulers adaptive suspension. The articulated dump truck is lighter compared to a rigid dum truck, with wider tires helping épread the load being carried, This hauler also has a sorter job life compared to a rigi dump truck, averaging between a few days to a few years as size limite what the truck is capable of offering over ai extended period: @ 3. (@) What is common rail direct injection (CRD!) system? “How is it different from conventional injection system? Ans.There are two different types of injection systems in the diesel engines or compression ignition (C I Engines). One is the Air Injection System and another one is Airless or Solid Injection System. In this post, we are going to learn about the Common Rail Direct Injection System CRDI System which comes under a solid injection system, ‘Automobile Engineering (220) ‘Technical Series ‘Common-Rail Direct Injection (CRDI) System : uatton nk] tn ress pore * Fig. : Common rail System High pressure relief Valve ‘Most. modern engine fuel’ systems use an advanced technology known as CRDi or Common Rail Direct Injection. Besides, both petrol and diesel engines use a common ‘fuel rail,’ which supplies the fuel to injectors. A.common rail is one of the most important components in a diesel “and gasoline direct. injection system. The main difference between a'direct and a standard injection is the delivery of fuel and the way how this one mixes with incoming am With conventional diesel injection systems, the fuel pressure has to be generated individually for each injection. With the common ‘rail system, however, pressure generation and injection. are separate, meaning that the fuel is constantly available at the required pressure for injection. ‘The primary difference between the two systems is how they are controlled. Conventional fuel injection systems are controlled mechanically while a common rail injection system is controlled using an electronic control unit. The electronic control unit regulates how much fuel is injected and the amount of pressure used. @ scanned with OKEN ScannerAutomobile Engineering (221) ‘Technical Series ‘Technical Seri (e22) Q 3 i Differentiate between transistor-based ignition st and capaciti tia eS system id capacitive discharge igniti, TCI and CDI both are improved technology of ignitic system used by a different automobile company. First ot you should know the full form of these two terms, Pull form of TCI - Transistorised Coil Ignition ~ Full form of CDI - Capacitor Discharge Ignition mobile Engineering Centrifugal clutch 5. Hydraulic clutch - Bloctromagnetic clutch Working of multiplate friction clutch - ulti plate clutch consists of more than dhe clutch plates eoary to Single plate eluteh which cotaista of only one plate. Friction surfaces are made in case of multi-plate Enutch. Due to increased number of friction surfaces, a multi- plate clutch can gransmit large torque. ° 4 One plate slides in, the, grooves on the flywheel and the next plate slides on spines provided on pressure plate. Thus, each alternate plate slides-in grooves on the flywheel,and the other on splines of pressure plate. If we take two consecutive plates, then one has inner and other has outer splines. Auto The main difference between them is capacitor dischary ignition is when a capacitor stored energy is used for ignitio while transistor-controlled ignition is when the ignition current is driven by a transistor. Let us have a deep insight into the comparison betw: transistorised coil and capacitor discharge ignition. Difference between TCI and CDI: ¢ CDI ignition system is independent on time while in Ti ignition system is dependent on time. + CDI Ignition makes the spark by discharging a capaci Joaded with high voltage about 200 to 450 volt from ignition coil by using an SCR known Thyristor while Ignition charges the coil with the current before the spark is done. Spark is done when the current is cut suddenly. ¢ CDI coils have low impedance and inductance is about XL< ohm and can reach high RPM makes high power and 61 sparks while TCI coils have high impedance is about XL >I ohm and can reach lower RPM thus spark duration may longer. x Q 4. (a) Classify different types of clutches. Describe ¢ working of multiplate friction clutch. WORKING OF MULTI PLATE CLUTCH + During elutch engagement, spring pressure forces the pressure plate towards engine flywheel. This causes the friction plates and the steel driven plates to be held together. ¢ Friction locks them together tightly. Then the clutch basket, drive plates, driven plates, clutch hub and the gearbox input shaft all spin together as one unit, * Now power flows from the clutch basket through the plates to the inner clutch hub and into the mai te the fans '0 the main shaft of the Ans.Different types of clutches 1. Single plate clutch 2. Multiplate clutch 3. Cone clutch @ scanned with OKEN Scanner(223) ‘Technical Serie ‘Automobile Engineering ee Ce rea aaal ox daengged when th dich oag| 2S Sal pais is pressed. This causes the clutch pressure plate to be moved T= 142475.5 N-mm = ‘away from the drive and driven plates, overcoming the] and T= hk WORX Rib P) R =HQnxRx bxP)R = 02 (2xmxn 400867) z 142475.5 = (0.2) (nx 0.0657) R3 R= 2451997.99 clutch spring force. ‘This movement of the pressure plate, relieves the spring pressure holding the drive and driven plates together. Then} the plates float away from each other and slip axially. ‘Thus, the clutch shaft speed reduces slowly. Finally, the clutch shaft stops rotating. Power is no longer transferred into the transmission gearbox. : 4(@) A cone clutch with a cone semi angle of 12° is transmit 11.19 kW at 750 r.p.m. The width of the face iy With of the mean diameter and the normal pressurg hetween the contact faces is not to exceed 0, Latlem®, Allowing the coefficient of friction of 0. determine the main dimensions'of the clutch and thd axial force required. (R= 151.12] b n=R+3sinz ‘Ans.Given, (One angle (semi angle) = 12°= 0 #161 + 22:58 sin 12° ein scl “2 sin 12? =e, . Normal force CHRO = 2n(0.0657) (151) (75.76) 0.67 Kgficm? = 4709.92 N = 0.0657 Nim? axial force required, Fa = Fy sin a . w=02 = 4709.92 x sin 12 ‘Torque is given as 978.24 rabeatexen : R= 979 NAns. (a) What is nie is gearbox? Why do we 106 sive ices Automobile State various functions ofa gearbox. 2xRX *. A gearbox ji a aT ut 8 mechanical component used to change the and increase the motor's torque in layman's @ scanned with OKEN ScannerAutomobile Engineering terms, Now regarding the location of the gearbox in the it is connected to the motor from one end. The shaft of 1 motor is associated with the gearbox via gears. ‘The purpose of a gearbox is to increase or reduce speed. Ag result, torque output will be the inverse of tho ap. function. If the enclosed drive is a speed reducer (ep, is less than speed input), the torque output the drive increases speed, the torque output wi decrease. ‘The Functions of Gears Gears have various functions as precision component p: ona machine, such as: Gears for Setting the Rotate Speed : The gears adjust the rotating speed of power, The example is gears motor engine. The gears regulate the power by giving ce gear ratios. We can increase’ or decrease the motor rpm installing a gear with a ratio of 1: 2 for an electric motor th has 1400 rpm. 2, Gears for Transmitting Power the gears can transmit. power wit without causing slippage. You can find this fun Jathe machine. The motor contained in a lathe machine not be the main shaft’ tovmove the chuck directly. That ‘why gear is needed to transmit from the motor to the shat ‘The second function. interconnected moving the chuck. 3. Gears for Changing Torq : Torque is a rotating fo torque can be done by providing a gear. As long as diameter of the gear is lurge, the torque greater (this also applied vice versa). 4. Gears for Changing the Power Direction : Besides g can adjust the speed to cl direction of power. It can be found on dam gates reservoirs, We can turn the door turn up and down when turn the door handle using gears. —— Thi ito Bogincering (226) Technical Series gretch the layout of a synchromesh gearbox used any Indian automobile. 1g type of gearbox is similar to the constant mesh type in ‘mt all the gears on the main shaft are in constant mesh Uhh the corresponding gears on the layshaft. The gears on win ayshaft are fixed to it while those onthe main shaft are neta rotate on the same. Its working is also similar tothe Fretatant mesh type, but in the former, there is one definite comrovement over tho latter, This is the provision of Wfachromesh deviee which avoids the necessity of double. smirutching. The parts which ultimately are to be engaged itt first brought into frictional contact which equalizes their Speed, after which these may be engaged smbothy. Construction Of Synchromesh Gearbox: a Tt consists of Clutch shaft, Layshaft, main shat Synchromesh device. The gears on layshaft are rigidly xed while gears on the main shaft are fre to rotate on the ait shaft with respect to the speed of layshaft. oe aynchromesh device is used *> between two main shaft Bea engaged smoothly. and Serer © scanned with OKEN Scannerobile Engineering (226) a asionobileBnsineering (228) techie Seres qts main functions are: ‘Technical Sex haft having cl 1 B rotate at engi speed, gear B, C, D, Eare on the main shaft and gear U3, and Ud are the gear on the Inyshaft. US is q intermediate gear. Fl and F2 are the synchromesh mombeq} free to slide on the main shaft which is spline internally, G1 and G2 are the ring shape members having internal tee which fit onto external teeth of member Fl and F2, K1 an K2, Li and L2 are dog teeth on gear B, C, D, E, TI, and 1y| are the ball supported by spring. Si and S2 are the forks. Working of Synchromesh Gearbox: To obtain low gear, member F2 moves towards the left which causes the friction contact between the cone-shaped surface of gear D and member F2. The friction or rubbing makes the speed equal then member G2 override to the left to engage with teeth K2 and low gear is obtained. Si member F2 slides toward the right, mesh with gear E, reverse gear is obtained. Similarly for second gear the member F1 and G1 are slides to the right so that finally the internal teeth on G1 have engaged with LI then the drive to the main shaft from gear B - U1 - U2~ gear C - Gi- Fito spline. A direct gear is obtained by sliding member Fi toward left. (a) What is a torque converter? Sketch and explain the construction and working of a torque converter. In what respect is it different from a fluid flywheel? -A torque converter is a type of fluid coupling which is used to transfer rotating power from the engine of a vehicle to the transmission, It takes place of mechanical clutch in an automatic transmission. The main function of it is to allow the load to be isolated from the main power source. It sits in Joad when it stops, in the fe engine from load and keep. engine running when vehicle stops, It transfers the power from engine to the transmission input shaft. It drives the front pump of the transmission. I It multiplies the torque of the engine and frahsmits it to the ion. It almost doubles the output torque. Working Principle For understanding:the working principle of torque converter, let's take.two fans. One fan is connected to the power source and other is not connécted with power source. When first fan ‘connected tothe power source starts moving, the air from it flows to the second fan which is stationary. The air from the first fan strikes on the blades of the second fan and it also starts rotating almost at the same speed to the first one. When the second fan is stopped, it dves not stop the first one, ‘The first fan keeps rotating. On the same principle the torque converter works. In that the impeller or pump acts a0 frst fan whieh is connected to © scanned with OKEN Scanner