Automotive Electrical & Electronics Level I PDF

Automotive Electrical & Electronics Level – I Apply automotive mechanical system fundamentals.  This module covers the units:  Basic operation, functions and principle engine Mechanical system fundamentals  Identify and locate engine mechanical system fundamentals  Basic...

Automotive Electrical & Electronics Level – I Apply automotive mechanical system fundamentals.  This module covers the units:  Basic operation, functions and principle engine Mechanical system fundamentals  Identify and locate engine mechanical system fundamentals  Basic operation, functions and principle of gasoline and diesel fuel systems  Unit one: Basic operation, functions and principle engine mechanical system fundamentals   Basic principle of engine operation A Heat Engine (HE) is a work developing machine which converts Thermal (Heat) Energy into Mechanical Energy (Work or Power). Heat Engine (HE) External Combustion (EC) Internal Combustion (IC) Reciprocating Rotary Reciprocating Rotary Steam Engine Steam Turbine Spark Ignition (SI) Compression Ignition (CI) (Otto Cycle) (Diesel Cycle) Two-Stroke Four-Stroke Two-Stroke Four-Stroke  Con…. Main Parts of a Motor Vehicle (Automobile) Chassis Body IC Engine Power Train Ride Control Electrical Frame, Systems Systems Suspension, Wheel and Tyre Body Chassis  Con…. Main Components of IC Engines IC Engines Mechanisms Systems Crank Gear Starting Valve Gear Intake Fuel Ignition Exhaust Charging Lubrication Cooling  Con…. Main component parts (elements) of the Crank Gear Mechanism (CGM) 2 1. Cylinder 2. Cylinder Head 1 4 3. Piston 5 3 4. Piston Rings 6 5. Piston Pin 6. Connecting Rod 7 7. Crankshaft  Con…. Main components parts (elements) of the Valve Gear Mechanism (VGM) 5 1. Camshaft (Cam) 2. Follower 3 3. Push Rod 4. Rocker Arm 2 1 5. Valve Spring 6. Valve  Con…. Valve Timing Diagram TDC VGM 80 100 IVO Ignition CGM EVC Compression Chain EVO Drive IVC 350 300 BDC Crankshaft Exhaust Power Camshaft Engine Mechanisms Valve Timing Diagram  Con…. Cylinder Numbering and Direction of Crankshaft Rotation Rear (Flywheel Side) Left Bank Right Bank Front In-Line Engine V- Engine Front Direction of Crankshaft Rotation CW Rear (Flywheel Side)  Con…. IC Engine Terminologies Engine Terminologies Clearance TDC Volume (Vc) TDC = Top Dead Center Swept d BDC = Bottom Dead Center Volume (Vs) s Stroke (s) l Bore (d) BDC Clearance Volume (Vc) or Combustion Chamber  d2 Swept Volume (Vs)  s 4  Cylinder Volume (V)  Vc  V s V s V Compression ratio (r)  V  1  V c c rcr Con-Rod length (l) s Crank radius (rcr)  2 Crank angle ( ) A ‘Full-Sectioned’ Engine ‘Front View’ (both ‘Valves’ are being rotated by 900)  Con…. Firing Order (FO) and Firing Interval (FI) Front Firing Order (FO) 1 – 3 – 4 – 2 (Crankshaft) 720 0 2 3 2,3 Firing Interval (FI)   180 0 4 Firing Order Strokes 1 P E I C 3 C P E I 4 I C P E 2 E I C P 00 1800 3600 5400 7200 Firing Order (FO) and Firing Interval (FI) of a Four-Stroke, Four-Cylinder, In-Line Engine.  Con…. Operation of IC Engines Spark Plug TDC Air + Fuel BDC p (bar) pmax Combustion (Qin) Power Expansion Ignition EVO Compression Exhaust IVO Intake Compression Power Exhaust Stroke Stroke Stroke Stroke TDC BDC V (m3) EVC Intake IVC Operation and Cycle Processes of a Four-Stroke, SI Engine.  Con…. Naturally Aspirated (NA) Operation of a Four-Stroke, SI Engine. Video  Con…. Operation of a Four-Stroke, Four-Cylinder, SI Engine.  Con…. Crankcase Compressed (CC) Operation of a Two-Stroke, SI Engine. Video  Con…. Stroke Movement of Position of the Valve Purpose the Piston Intake Valve Exhaust Valve Intake Going Down Open Close  Sucked air/fuel mixture into the cylinder Compression Going Up Close Close  Compressed the air/fuel mixture to increase its temperature Power Going Down Close Close  Combustion takes place Exhaust Going Up Close Open  Burned gases pushed out from the engine cylinder Engine component parts 1 - Distributor 2 - Valve cover 3 - High tension cables 4 - Tappet 5 - Air cleaner 6 - Timing pulley 7 - Camshaft 8 - Water pump 9 - Timing belt 10 - Connecting rod 11 - Crankshaft pulley 12 - Oil sump 13 - Strainer 14 - Crankshaft 15 - Engine block 16 – piston Excessive exhaust smoke or noise from a car can be a sign of a mechanical problem that needs to be addressed by a professional: Smoke The color of the smoke can indicate the problem: White smoke: This could be a sign of a blown head gasket, which allows coolant to leak into the combustion chamber. However, if the smoke is thin and goes away after the engine warms up, it's likely just condensation from the tailpipe. Blue smoke: This could be a sign that oil is burning, which could be caused by worn valve seals, piston rings, or turbochargers. Black smoke: This could be a sign that too much fuel is being burned, which could be caused by a malfunctioning fuel injector, carburetor, or oxygen sensor. Grey smoke: This could be a sign of excess oil, a PCV valve failure, or a transmission fluid leak Unusual engine noises or vibrations can indicate a number of issues, including: Clicking, ticking, or tapping This could indicate a problem with the valves or pistons, or that the engine oil is low. Squealing A squealing noise could mean that one of the engine belts is loose or worn out. Knocking This can sound like a "rattle ", "cancan ", or "kinkin ". It could be caused by a problem with the engine bearings. Grinding This could be a symptom of low transmission fluid. Hissing This usually means that one of the rubber hoses has a crack, hole, or other failure.  Con…. Loud noises This could be a problem with the exhaust system. Other signs include reduced mileage, odd vibrations of the steering wheel or gas pedal, and increased noise of the engine. Clicking while turning This could be a problem with the CV (constant velocity) joint, which lubricates the front axles. Other causes of engine vibration include faulty spark plugs, wires, or coils, dirty or clogged fuel injectors, filters, or air intake, and worn or damaged belts, pulleys, or tensioners. You should not ignore strange noises coming from your vehicle, as it's a sign your car needs help. You should act fast and get a professional mechanic to diagnose the problem.  Unit Two: Identify and locate engine mechanical system fundamentals  Identify and locate engine mechanical system fundamentals Automotive Engine System Fuel system( diesel and Gasoline) The fuel system consists of the fuel tank, pump, filter, and injection nozzles or carburetor and is responsible for supplying fuel to the engine as needed. Every component must function properly in order to achieve the expected vehicle performance and reliability. Gasoline Fuel system  Con…. The purpose of the fuel supply system for a petrol engine is to store, transfer and filter the petrol required by the float chamber of a carburetor. The most important components of this system are:  Air cleaner  Carburetor  Fuel tank  Fuel line  Charcoal canister (some models only)  Fuel filter  Fuel pump  Con…. In fuel supply system, air cleaners or air filters remove dust, dirt and other foreign particles present in the air and send clean air into engine cylinder. Fuel filters filter foreign particles that may be present in the fuel. A fuel pump lifts fuel from the fuel tank and supplies the same to the carburetor through tubes and hoses (fuel lines). Correct quantity of air fuel mixture is supplied to the cylinder by carburetor. On some models, the HC (Hydrocarbon) gas generated in the fuel tank is temporarily absorbed in the charcoal canister and is burned in the engine. As a result, the amount of HC gas which leaks out of the fuel tank is reduced.  Diesel-Engine Fuel Systems In a diesel engine, air is compressed within the cylinder, which raises its temperature significantly. The fuel is then injected directly into this highly pressurized and hot air. The heat of compression causes the fuel to ignite spontaneously, driving the piston down the cylinder and generating power. Con…. Con…. Con….  Exhaust system An exhaust system is a set of components that removes waste gases from an engine or stove and releases them into the atmosphere. It also reduces the noise made by the engine when expelling gases. Here are some components of a vehicle's exhaust system: Exhaust manifold: Connects to the engine's cylinder heads and sends toxic gases to the catalytic converter Catalytic converter: Changes toxic gases into less harmful ones Muffler: Reduces engine noise through reflection, absorption, and destructive interference of sound waves Tailpipe: Releases the final gases into the atmosphere Exhaust header: An alternative to the exhaust manifold that improves engine performance by eliminating backpressure Oxygen sensors: Measure the amount of oxygen in the exhaust system and waste gases Con…. Con…. Cooling system Which include the radiator, lower house; water pump, water jacket, thermostat, upper hose and radiator also fan. Water Pump: -Is a centrifugal type pump, it increases the flow rate of the water Fan It draws fresh air through the radiator and thus increases the efficiency of the radiator in cooling hot water Radiator: -The purpose of the radiator is to cool down the water received from the engine, it has three main parts: - upper tank, Lower tank and Tubes Thermostat:-It is a kind of check valve which opens & closes with the effect of temperature The normal operating temperature of an engine is 80-900c. Water Jacket: -It provided a way for the coolant to circulate & take off the heat from the engine component. Lubrication System The engine uses a combination pressure/splash lubrication system, delivering oil under pressure to crankshaft, connecting rod and main bearing surfaces. Other component areas are splash lubricated. A high-efficiency greater oil pump maintains high oil flow and oil pressure, even at low speeds and high operating temperatures. A pressure relief valve limits maximum pressure of system. Oil pan must be removed to service oil\ pickup and oil pump.  Identifying Vehicle mechanical system A vehicle's mechanical system is made up of many parts and devices that work together to perform specific functions. Some of the main mechanical systems in a vehicle include: Engine: Powers the vehicle Transmission: Transfers the engine's power to the wheels Brakes: Slows down and stops the vehicle Steering: Controls the car's motion Suspension: Stabilizes the car while driving Cooling system: Manages the engine's temperature Electrical system: Includes a battery and other components Exhaust system: Regulates emissions  Main Engine Systems 2 3 1. Starting System VGM 2. Intake System 5 3. Fuel System 4 4. Ignition System 8 6 5. Exhaust System 1 6. Charging System CGM 7. Lubrication System 8. Cooling System 7 Starting system This includes the battery, ignition switch, starting motor and ring gear of flywheel. Battery: -provide electrical power to the starter motor Switch: -it controls the starter circuit Starter Motor: -It converts the electrical energy to mechanical energy & rotates the crank shaft with a minimum cranking speed Ring gear at fly wheel: -it takes the starter motor torque to the engine crank shaft Charging system This includes the battery, ignition switch and alternator (generator) regulator. It is the system which supply electricity to the electrical load & charge the battery after the engine is started Battery: -It is the primary sources of electricity to the vehicle Switch: -Which operate the circuit of the charging system Alternator: -Which convert the mechanical energy of the engine to electrical energy Regulator: -It makes the output of the alternator not mover than 12v.  Transmissions and Drive Trains Systems Definition Of Transmission System :- The Mechanism that transmits the power developed by the engine of automobile to the engine to the driving wheels is called the Transmission system (or power train).It is composed of Clutch , The gear box, Propeller shaft, Universal joints ,Rear axle Wheel Tires Requirements Of Transmission System Provide means of connection and disconnection of engine with rest of Wheel ,Tires. Clutch, The gear box ,Propeller shaft, Universal joints , Rear axle  There are two types of transmissions in use— Con….  Manual transmission  Automatic transmission Manual transmission, the driver selects all gears manually using both a movable gear selector and a driver-operated clutch. This type of transmission is also known as a "stick shift" or a "standard" transmission. Automatic transmission That uses a torque converter, planetary gear set and clutches or bands to shift through a vehicle's forward gears automatically. Some automatics allow the driver a limited amount of manual control over the vehicle (aside from choosing a forward, reverse or neutral mode) -- for example allowing the driver to control up shifts and downshifts by utilizing buttons or paddles on the steering wheel or the gear selector. Common names for such transmissions are "shift able automatic," "Tiptronic" and "auto stick." Con…. Steering System In front wheels can be turned to left and right by steering system so that the vehicle can be steered. The steering wheel is placed in front of driver. It is mechanically linked to the wheels to provide the steering control. The primary function of the steering system is to provide angular motion to front wheels so that vehicle can negotiate a turn. It also provides directional stability to vehicle when the vehicle moves ahead in straight line. Now-a-days, many vehicles are equipped with power steering which uses pressure of a fluid to reduce steering effort. When driver turns the steering wheel, a hydraulic mechanism comes into play to provide most of the effort needed to turn the wheel.  Con…. Basic Steering Systems Two basic kinds of steering systems are in use today:  Linkage (worm gear) steering systems  Rack-and-pinion steering systems Each may be operated manually or with power assist  Suspension system The primary functions of the suspension system include maximizing the contact between the tires and the road surface, providing steering stability and good handling, evenly supporting the weight of the vehicle (including the frame, engine, and body), and ensuring the comfort of passengers by absorbing and dampening. Components of Suspension System Knuckle or Upright. Linkages. Wheels/tires. Dampers/Shock Absorbers. Springs. Struts. Anti Sway Bars. Ball Joint Con….  Brake System Brake system enables the vehicle to stop and slowdown. Braking force takes place when the driver applies pressure and continuous application to the brakes will enable the vehicle to stop. The following are the methods of stopping the rotational movement of the tires:  Con…. Brake Pedal:-When the brake pedal is depressed, force is applied to the master cylinder. The force that the pushrod applies to the master cylinder piston is, therefore, much greater than the force applied to the brake pedal.  Con…. Parking brakes Parking brakes or handbrakes are mainly used when the car is parked. The mechanical brake system locks the rear wheels. Engine brake Engine brake used the retarding effect of engine when the vehicle is in gear and throttle valve is closed.  Unit Three: Basic operation, functions and principle of gasoline and diesel fuel systems  gasoline and diesel fuel system The basic operation of a gasoline or diesel fuel system is to store and supply fuel to the engine, where it is mixed with air and burned to produce energy: Fuel storage: The fuel tank stores the fuel until the engine needs it. Fuel delivery: The fuel pump draws fuel from the tank and delivers it through fuel lines to a filter. The filter removes impurities from the fuel. Fuel injection: The fuel injectors push the fuel into the combustion chamber, where it mixes with air. Ignition: The spark plug ignites the fuel-air mixture in a gasoline engine, while the heat of the compressed air ignites the fuel in a diesel engine. Power: The combustion of the fuel powers the engine.  Con…. Here are some other components of a fuel system: Fuel pressure regulator: Maintains consistent fuel pressure throughout the process. Governor: Regulates the fuel supply to the engine based on the engine's load. Diesel engines are known as compression-ignition engines, while gasoline engines are spark-ignition engines. AIR CLEANERS The operating efficiency, good performance and durability of an engine depend mainly upon its cleaner. It is a device, which cleans and filters the air before entering the combustion chamber of an engine.  Air Cleaner and its types Con…. Dry (Paper) type Air Cleaner dry-type air cleaner is a type of air filter that uses a paper element to strain dust and other particles from the air: Characteristics Simple in design Axial-Flow Paper type Highly efficient Easily maintained Mounted in any position to suit available under bonnet space.  Con…. Oil-Bath Air Cleaner The wire mesh filter should be cleaned by washing in a suitable cleaning fluid. The bath should also be cleaned and refilled with the recommended grade of oil to the correct level. Under normal operating conditions servicing intervals should be between 5000 km and 8000 km. However, under extremely bad atmospheric conditions of dirt and dust, more frequent servicing may be required.  Servicing of Air Cleaners Necessity for Maintenance The air taken in by the engine contains dust and other particles which clog the carburetor passage, cause rapid engine cylinder wear and oil deterioration. The air cleaner traps the dust and dirt particles in the air with its filter, preventing them from entering the carburetor and engine cylinders. Inspection of Paper type Air Cleaner  Con…. Remove Air Cleaner Element  Unscrew the wing nut and release the clips.  Remove the air cleaner cover and take out the element. Inspect Air Cleaner Element  If the element is full of dirt and dust, replace it.  The effectiveness of a filter element that is nearly ready for regular periodic replacement will not be recovered by cleaning, so it should be replaced.  A filter element impregnated with water or oil should be replaced, as trapped dust and sand cannot be removed with compressed air.  Con…. Clean Air Cleaner Element Using an air gun, blow the dust and sand particles out from the lower surface. Next, clean the upper surface and once again blow evenly from the lower surface. Clean Air Cleaner Case Con…. First use a rag to wipe out the dust from inside the case, then blow with compressed air. Be careful to prevent even the smallest particles from entering the carburetor. Check that the sealing on the case or cover is not peeling. If it is, repair it. Improper sealing will cause unfiltered air to enter the engine.  Con…. Assemble Air Cleaner Install the element correctly in the air cleaner case and assemble the case cover. To install the element, align the tabs on the case, element and cover. Fasten the clamps and tighten the wing nut by hand.