Unit 1 INTRODUCTION TO AUTOMOTIVE ENGINEERING AND MECHANICS.pptx

INTRODUCTION TO AUTOMOTIVE ENGINEERING AND MECHANICS

1. Unit-1: INTRODUCTION TO AUTOMOTIVE ENGINEERING AND MECHANICS History - Development of vehicles and drive units - Stages in the development of automotive transmissions, Development of gear-tooth systems and other - Transmission components- Basic elements of vehicle and transmission engineering, Need of gearboxes, Functions of vehicle transmissions, Fundamental performance features of vehicle transmissions, Trends in transmission design, Transmission losses and efficiency.

2. Year Inventor Features 1881 Trouve (France) EV tricycle 1885 Carl Benz (England) IC engine based tricycle 1886 Gustave Phillipart (Belgium) Electric bus 1888 Phillip.W.Kart (USA) Four wheeler EV 1889 Andrew L Ricker ( Newyork ) Tricycle – 1/6HP, 100lbs battery, Range upto 48km at 13km/h Four wheeled EV – 140kg, 0.5HP, 6kg battery. Vehicle can carry only one person at 19km/h for 4hrs 1895 Morris and Salom (Pennsylvania) Two seated electric boat-Methodology was used to build taxis. 1899 Camille Jenatz (Belgium) IC Engine race car 1906 Ford (USA) Model K 1909 Ford (USA) Model T 1912 Ferdinand Porsche Porsche No.1 – Lohner Wagen Race cars – Lohner Porsche Rennwagen (180kg) History of Vehicles 2

3. Year Happening 1960 Interest in EV (air pollution by gasoline vehicles), Eureka williams corporation converted gasoline vehicles (Renault Dauphine) to EV Mid 1960s Scottish aviation Ltd built scamp EV, GM and Ford experimented with the transition to EV 1966 Enfield 8000 car was designed as an EV, Car Chasis –steel and holds 8 lead acid batteries. It had 6kw DC motor; 975 kg weight and max speed is 64km/h 1966 Ford designed Commuta car. Uses two DC motor each weighing 18kg. Late 1960s GM produced Electrovair and Electrivan 1972 Sebring vangaurd (Florida) produced low cost two seater , citicar . Mid 1970s Jet industries, Mc Kee Engg , Electric Vehicle Associates 185 cars sold in short time 1.Fiat – X1/23B (1975) 2.Globe union Endura (1977) 3.GE continental (1978) 4.GE Chrysler (1979) 1980’s Ford/GE sponsored by US Government to develop vehicles with AC drives. Peugeot 205, Citreon C15 – Electric Vans 3

4. Functions of Gear Box To provide variation in speed and torque. To provide reverse movement of vehicle without changing the direction of rotation of crankshaft. Stages in the development of automotive transmissions

5. Advantages Since only one gear is in mess in the sliding mesh gearbox so less fluctuating loads on shafts causing less vibration and noise. Its manufacturing and mechanism are easy. Disadvantages Only spur gears can be used as gears not helical gears More effort is required to engage the gear as the gear has to be slided in sliding mesh gearbox. Less life of gear as more wear and tear of gear is caused in sliding mesh gearbox due to friction. It takes more time and money to replace the gears if the gearbox fails.

6. Advantages Uses helical gears. Less damage since all harm is for dog clutch, teeth belonging to the gear wheels remain intact. Disadvantages •It is less efficient. •More vibration and complex mechanism

7. Salient features :- The clutch shaft and main shaft are in-line while the lay shaft is parallel to them. The main shaft gears are free to rotate , while lay shaft gears are fixed to it. The system incorporates a synchronizing mechanism which allows the member first brought into friction contact Synchronizers In automobiles, a synchronizer is part of a synchromesh manual transmission that allows the smooth engagement of gears. Advantages : Smooth and Noise free shifting of gears which is most suitable for vehicles. No loss of torque transmission from the engine to the driving wheels during gear shifts. Less vibration. Quick shifting of gears without the risk of damaging the gears. Disadvantages : High manufacturing cost and the number of moving parts. Noisy Improper handling of gear may easily be prone to damage.

8. Development of gear-tooth systems Spur Gear In spur gear the teeth cut is parallel to the axis of shaft Easy construction Transmit large amount of power Produce noise during engagement and disengagement Not used for high speed Applicable for few watt to 500kW Presence of more noise and vibration due to sudden contact between mating teeth

9. Helical Gear In helical gear teeth cut at an angle of face of gear which is not parallel to axis of shaft. Used for high load applications. Less noise due to curve profile teeth Needs good quality of lubrication Costly Applicable for high power upto 1 MW Less noise and vibration since teeth of two mating gears gradually come into contact

10. Bevel Gear This is the type of gear in which the axis of shaft intersect the line of teeth cut on the face of gear. Not desirable for high speed reduction. Speed reduction upto 5:1. Applicable for power upto 300 kW Straigh teeth bevel gears – more vibration and noise Spiral teeth bevel gears – reduced vibration and noise

11. Worm and Worm Gear There are two elements – Driving element(Screw) and Driven element (Gear). Used for high velocity ratio (upto 300:1) Supports self-locking It produces a lot of heat. Applicable for the limited power upto 100 kW Smooth and silent

12. Components of Transmission System in Automobiles 1. Clutch (Manual Transmission) Flywheel : Connects to the engine and rotates to transfer power. Clutch Disc : Friction disc that engages and disengages from the flywheel to transmit power. Clutch Pedal : Allows the driver to engage or disengage the clutch. 2. Gearbox (Transmission) Gears : Different-sized gears that alter the torque and speed of the vehicle. Input Shaft : Connects to the clutch and transfers engine power to the gearbox. Output Shaft : Transfers power from the gearbox to the drive shaft. Synchronizers : Help the gears mesh smoothly during shifts, preventing grinding. 3. Propeller Shaft Connects the transmission to the wheels of the vehicles through differential and axle. 4. Differential One of the key functions of the transmission system is to redirect motion by 90 degrees, aligning the axis of the propeller shaft with that of the live axle. The differential achieves this through a wheel and pinion arrangement. 5. Axle An axle is a rod or shaft that rotates the wheels and supports the weight of your vehicle. 6. Torque Converter (Automatic Transmission) Transmits that torque from the engine to a rotating driven load.

13. Basic elements of the vehicle

14. Types of Transmission Systems Automobiles employ two primary types of transmission systems: manual and automatic. Manual transmissions require driver input to shift gears, while automatic transmissions shift gears automatically, offering convenience and ease of use. The various types of Automobile Transmission Systems are: 1. Manual Transmission 2. Automatic Transmission 3. Semi-automatic Transmission:- a) Dual-clutch Transmission (DCT) b) Sequential Transmission 4. Continuously Variable Transmission (CVT)

15. Manual Transmission System in Automobile Manual transmission, also known as a stick shift or standard transmission , is one of the oldest and simplest transmission systems in automobiles. In this system, the driver manually selects and engages gears using a gear shifter and clutch pedal . By disengaging the clutch, the driver can smoothly change gears to control the power sent from the engine to the wheels. Manual transmissions give drivers a high degree of control over their vehicles but require more skill and effort to operate effectively.

16. Automatic Transmission System in Automobile Automatic transmission is a user-friendly alternative to manual transmission. It eliminates the need for manually shifting gears, making driving more convenient , especially in heavy traffic. An automatic transmission system uses a torque converter to regulate the power flow between the engine and the wheels. The transmission's hydraulic system automatically selects and engages the appropriate gear based on driving conditions, engine speed, and vehicle load , allowing for smooth and effortless gear changes.

17. Semi-Automatic Transmission System in Automobile Semi-automatic transmission systems offer a blend of manual and automatic control. They provide the option for the driver to shift gears without the need for a clutch pedal manually. Two common types of semi-automatic transmissions are: a) Dual-Clutch Transmission (DCT) A dual-clutch transmission uses two separate clutches for odd and even-numbered gears, allowing for rapid and seamless gear changes. Drivers can choose between manual gear selection or automatic mode, making DCTs popular for sports cars and high-performance vehicles. b) Sequential Transmission Sequential transmissions are often found in racing cars and motorcycles. They require the driver to shift gears sequentially, usually through a lever or paddle shifter. Unlike manual transmissions, there's no H-pattern shifter, and gear changes occur one at a time in a forward or backward sequence.

18. Continuously Variable Transmission (CVT) System in Automobile Continuously Variable Transmission, or CVT, is a modern and innovative transmission system that doesn't use traditional gears. Instead, it relies on a belt and pulley system to provide a seamless range of gear ratios. CVTs are known for their fuel efficiency and smooth acceleration, making them popular in many compact and hybrid vehicles. However, some drivers may find their operation different from traditional transmissions due to the absence of distinct gear changes.

19. Functions of Transmission System Transmit engine power to the wheels. Control the speed and direction of the vehicle. Provide variable gear ratios for different driving conditions. Enable smooth acceleration and deceleration. Allow the vehicle to come to a complete stop without stalling the engine. Facilitate efficient power delivery and fuel economy. Adapt to changes in terrain and road conditions. Enhance driving comfort and convenience. Enable reverse gear.

20. Advantages and Disadvantages of Transmission System Advantages of Transmission System in Automobile Gear Ratio Flexibility: Allows adapting to different driving conditions for optimal performance and fuel efficiency. Power Distribution: Transmits engine power to the wheels, enabling the vehicle to move. Smooth Acceleration: Facilitates seamless speed changes for a comfortable driving experience. Fuel Efficiency: Optimizes engine performance and conserves fuel by adjusting gear ratios. Control: Provides the driver with control over the vehicle's speed and power output. Towing Capacity: Enhances the ability to tow heavy loads with appropriate gear selection. Disadvantages of Transmission System in Automobile Complexity: Manual transmissions require driver skill, while automatics have intricate components, making repairs costly. Learning Curve: Manual transmissions necessitate practice and may be less accessible to some drivers. Maintenance: Transmissions may require periodic servicing and fluid changes. Wear and Tear: Over time, transmission components can wear out, leading to potential failures. Cost: Transmission repairs or replacements can be expensive.

21. Trends in transmission design Growing popularity of advanced automatic transmissions, such as Continuously Variable Transmissions (CVTs) and Dual-Clutch Transmissions (DCTs), for smoother and more efficient driving experiences. Development of 8-speed, 9-speed, and even 10-speed automatic transmissions to optimize power delivery and fuel economy. Implementation of intelligent transmission control units (TCUs) that adapt to driving conditions and driver behavior for optimal performance. Use of machine learning and artificial intelligence to predict and adjust transmission settings in real-time. Coordination between transmission systems and advanced driver assistance system (ADAS) for features like adaptive cruise control, automated parking, and collision avoidance. Use of lightweight materials such as aluminum and advanced composites in transmission components to reduce weight and improve fuel efficiency. Development of technologies to enhance shift quality, reducing noise, vibration, and harshness (NVH) during gear changes.

22. Transmission Losses and Efficiency