Electric Vehicles (EVs) mECHANICAL ENGINEERING

A Cleaner Future on Wheels, Powered by electric motors using battery
energy

• No internal combustion engine (or a hybrid)

• Types: BEV, PHEV, HEV

Battery Electric Vehicles (BEVs):
These are fully electric vehicles powered by rechargeable batteries and no gasoline engine, 

Plug-in Hybrid Electric Vehicles (PHEVs):
These vehicles can be powered by both an electric motor and an internal combustion engine, states the Department of Energy. 

Fuel Cell Electric Vehicles (FCEVs):
These vehicles use fuel cells to convert chemical energy from fuel (like hydrogen) into electricity to power the electric motor. 

1. Seminar Presentation Topic: Comparison of 4 - Stroke Petrol & Diesel Engine Sub: ELEMENTS OF MECHANICAL ENGINEERING [BEMEM203] Presented By: Name: Anshuman K Murthy USN: 1MV24ME002 Semester & Branch: 2 nd Sem , Mechanical Engineering Reviewer: Name: Prof. Chandrasekhar B Assistant Professor Department of Mechanical Engineering

2. Introduction 4-stroke petrol engine: Suction Stroke Compression Stroke Power Stroke Exhaust Stroke Comparison with a 4-stroke diesel engine Advantages, disadvantages & applications 2 INDEX

3. Engaging the audience What is a 4-stroke engine? A 4-stroke engine is a type of internal combustion engine that converts the chemical energy stored in fuel into mechanical energy. It does this by completing a cycle of four distinct piston movements, or “strokes,” for every power-producing event. This entire cycle requires two full revolutions of the crankshaft. 3 INTRODUCTION

4. Suction Stroke The piston moves downwards from the Top Dead Centre (TDC) to the Bottom Dead Centre (BDC). During this movement, the intake valve opens, and a mixture of air and atomized petrol (fuel) is drawn into the cylinder due to the vacuum created by the descending piston. The exhaust valve remains closed. 4

5. Compression Stroke With both intake and exhaust valves closed, the piston moves upwards from BDC to TDC. This action compresses the air-fuel mixture into a smaller volume, significantly increasing its pressure and temperature. This compression is crucial for a powerful combustion later on. 5

6. Power Stroke Just before the piston reaches TDC on the compression stroke, the spark plug ignites the highly compressed air-fuel mixture with an electric spark. The rapid combustion causes a sudden and powerful expansion of gases, forcing the piston forcefully downwards from TDC to BDC. This downward movement is where the actual mechanical power is generated, which then turns the crankshaft and ultimately drives the vehicle. Both valves remain closed during this stroke. 6

7. Exhaust Stroke As the piston reaches BDC after the power stroke, the exhaust valve opens, and the piston moves upwards from BDC to TDC. This upward movement pushes the burnt exhaust gases out of the cylinder through the open exhaust valve and into the exhaust system. The intake valve remains closed. Once the piston reaches TDC, the exhaust valve closes, and the cycle is ready to begin again with the intake stroke. 7

8. Differences between a 4-stroke petrol engine and a 4-stroke diesel engine 8 Feature 4-Stroke Petrol Engine 4-Stroke Diesel Engine Ignition Method Spark ignition (uses a spark plug) Compression ignition (no spark plug) Fuel-Air Mixture Pre-mixed before entering cylinder Air compressed first, then fuel injected Compression Ratio Lower (approx. 8:1 to 12:1) Higher (approx. 14:1 to 22:1) Fuel Used Petrol (gasoline) Diesel Thermal Efficiency Lower Higher (due to higher compression ratio) Engine Noise Quieter and smoother Noisier and more vibration Maintenance Generally simpler and cheaper Requires more robust components, higher cost Power Output Higher RPM, better acceleration Higher torque at lower RPM Cost Less expensive to manufacture and maintain More expensive due to stronger parts Application Cars, bikes, light vehicles Trucks, buses, heavy-duty vehicles

9. Advantages & Disadvantages 9 Aspect Advantages Disadvantages Fuel Efficiency More fuel-efficient due to one power stroke every four strokes Less power output per cycle compared to 2-stroke engines Emissions Produces fewer emissions (more environmentally friendly) More complex design increases initial cost Durability Longer lifespan due to lower wear and tear Heavier and larger in size Lubrication Oil is separate from fuel, so less oil consumption Requires a proper lubrication system, increasing maintenance complexity Cooling Runs cooler than 2-stroke engines More components mean more potential for mechanical failure Noise & Vibration Quieter and smoother operation More moving parts = more maintenance and repairs Torque Provides better torque at lower RPM Not as suitable for high-speed applications as 2-stroke engines

10. 10 THIS IS A SINGLE CYLINDER, 4 – STROKE, 659cc, DUCATI SUPERQUADRO MONO ENGINE

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