Engine Ignition and Fuel Systems Quiz
48 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary function of the choke in an engine?

  • To cool the engine
  • To control exhaust emissions
  • To regulate the volume of air entering the venturi (correct)
  • To increase fuel pressure

    • What system does the Electronic Fuel Injection (EFI) use to deliver fuel into the engine?

  • Gravity feed
  • Venturi carburetors
  • Electromagnetic fuel injectors (correct)
  • Mechanical pumps

    • Which of the following describes the Air-Fuel Ratio (AFR) for maximum power?

  • 10 parts air to 1 part fuel
  • 12 parts air to 1 part fuel (correct)
  • 15 parts air to 1 part fuel
  • 8 parts air to 1 part fuel

    • What are the advantages of electronic fuel injection compared to carburetors?

    <p>Improved engine efficiency and lower emissions</p> Signup and view all the answers

    What happens if the air-fuel mixture is too lean?

    <p>It results in insufficient fuel combustion</p> Signup and view all the answers

    What does a proper air-fuel mixture ensure in terms of engine performance?

    <p>Optimal combustion and better performance</p> Signup and view all the answers

    What role does the Electronic Control Unit (ECU) play in an electronic fuel injection system?

    <p>Manages fuel delivery precision</p> Signup and view all the answers

    Which pollutant can increase due to a lean air-fuel mixture?

    <p>Nitrogen oxides</p> Signup and view all the answers

    What happens to the voltage generated by the magneto as the engine speed increases?

    <p>It increases.</p> Signup and view all the answers

    Which vehicle types commonly use the Magneto Ignition System?

    <p>Buses</p> Signup and view all the answers

    What is one advantage of the Magneto Ignition System over the Battery ignition system?

    <p>Requires no electricity supply</p> Signup and view all the answers

    What is a key advantage of the multipoint injection system over the single injection system?

    <p>It provides individual control over each cylinder.</p> Signup and view all the answers

    What component is NOT part of the coil ignition system?

    <p>Flywheel</p> Signup and view all the answers

    Which sensor measures the position of the crankshaft and the engine's speed in the multipoint injection system?

    <p>Inductive pickup</p> Signup and view all the answers

    What is the initial drawback of the magneto ignition system during engine starting?

    <p>Poor spark quality</p> Signup and view all the answers

    In a multipoint injection system, how does fuel typically reach individual injectors?

    <p>Through a fuel distributor with individual tubes.</p> Signup and view all the answers

    Which component acts as the energy source in the coil ignition system?

    <p>Battery</p> Signup and view all the answers

    What is the function of the cut-off fuel valve in the multipoint injection system?

    <p>To cut off the fuel supply when the engine is switched off.</p> Signup and view all the answers

    Which system improves efficiency due to a high-intensity spark?

    <p>Magneto ignition system</p> Signup and view all the answers

    What is measured by an air-flow meter in the multipoint injection system?

    <p>Speed and quantity of air flowing through a tube.</p> Signup and view all the answers

    What does the primary circuit of the coil ignition system include?

    <p>Ignition switch and contact breaker points</p> Signup and view all the answers

    Which type of fuel injector system is commonly used in a multipoint injection system?

    <p>Indirect injection.</p> Signup and view all the answers

    Which actuator is responsible for controlling the throttle in a multipoint injection system?

    <p>Idle Air Control Valve (IACV)</p> Signup and view all the answers

    What component directs high voltage current to the spark plugs in the correct firing order?

    <p>Distributor</p> Signup and view all the answers

    What is the primary purpose of exhaust gas recirculation (EGR) in multipoint injection systems?

    <p>Reduce nitrogen oxide (NOx) emissions.</p> Signup and view all the answers

    Which component replaces the contact breaker points in an electronic ignition system?

    <p>Armature</p> Signup and view all the answers

    What is a major limitation of the conventional contact breaker ignition system mentioned?

    <p>Inefficiency at low speeds</p> Signup and view all the answers

    What does the electronic control unit (ECU) do in an electronic ignition system?

    <p>Senses the signal from the pickup coil</p> Signup and view all the answers

    At what rate can a conventional contact breaker provide satisfactory performance?

    <p>400 sparks per second</p> Signup and view all the answers

    Which component in the electronic ignition system performs a similar function as the ignition coil in previous systems?

    <p>Distributor</p> Signup and view all the answers

    What is a significant improvement of the electronic ignition system over the coil ignition system?

    <p>Reduced engine speed limitations</p> Signup and view all the answers

    Which part stops the current flow from the primary circuit in an electronic ignition system?

    <p>Electronic Module</p> Signup and view all the answers

    What is the main purpose of the inductive pickup sensor in an electronic fuel injection system?

    <p>To provide the crankshaft position and engine speed</p> Signup and view all the answers

    What is the primary advantage of multipoint injection over single point injection?

    <p>Improved fuel atomization</p> Signup and view all the answers

    Which sensor indicates the throttle opening to the electronic control unit?

    <p>Throttle potentiometer</p> Signup and view all the answers

    Which component directly injects fuel into the engine's air stream?

    <p>Fuel injector</p> Signup and view all the answers

    What does the automotive oxygen sensor monitor in real time?

    <p>Air fuel ratio</p> Signup and view all the answers

    What is the role of the throttle plate control in the electronic fuel injection system?

    <p>Regulates idle airflow</p> Signup and view all the answers

    What is a characteristic feature of single point injection systems?

    <p>A single injector or pair of injectors in a central location</p> Signup and view all the answers

    Which of the following components serves as the fuel dispensing nozzle in an electronic fuel injection system?

    <p>Fuel injector</p> Signup and view all the answers

    What is the primary advantage of using a Distributorless Ignition System (DIS) over a traditional electronic ignition system?

    <p>Lower maintenance requirements</p> Signup and view all the answers

    How does a Distributorless Ignition System control the timing of the spark?

    <p>With an Ignition Control Unit and Engine Control Unit</p> Signup and view all the answers

    What component does a Distributorless Ignition System use for each spark plug?

    <p>One ignition coil per cylinder</p> Signup and view all the answers

    What does the absence of a distributor in a Distributorless Ignition System eliminate?

    <p>Mechanical and electrical wear and tear</p> Signup and view all the answers

    Which of the following systems faces more mechanical and electrical issues over time?

    <p>Electronic ignition system</p> Signup and view all the answers

    What feature makes the Distributorless Ignition System more efficient?

    <p>Direct voltage supply to spark plugs</p> Signup and view all the answers

    Which component is NOT part of the Distributorless Ignition System?

    <p>Distributor</p> Signup and view all the answers

    Why does the spark timing accuracy decrease over time in electronic ignition systems?

    <p>Wear and tear of distributor components</p> Signup and view all the answers

    Study Notes

    Petrol Engine Fuel Supply System

    • The petrol engine fuel supply system consists of components like the petrol tank, connecting pipes, fuel filter, fuel pump, air cleaner, inlet manifold, and carburetor.
    • The petrol tank acts as a fuel reservoir, usually placed at the rear of the vehicle (especially in front-engine vehicles).
    • Connecting pipes transport fuel from the tank through the filter, pump, and to the carburetor.
    • The fuel filter removes dust and dirt from fuel, preventing it from entering the carburetor.
    • In modern vehicles, a lift pump is often used to force fuel from the tank to the carburetor. Mechanically driven pumps are usually mounted on the engine, while electrically driven pumps are common as well.
    • The air cleaner filters out dust and dirt from the air mixture.

    Functions of the Carburetor

    • The carburetor meters air and fuel, thoroughly atomizing the fuel to mix correctly with the air for combustion.
    • It adjusts the air-fuel ratio based on speed and load.
    • The mixture strength (ratio of air to fuel) varies with engine conditions.
    • Common mixture strengths include 15:1 (starting), 11.5:1 & 13:1 (idling), 12:1 (maximum power) & 16:1 (economy).

    Operation of a Simple Carburetor

    • The float chamber holds fuel.
    • The float maintains fuel level by controlling the flow of fuel into the chamber.
    • The throttle valve controls the volume of air/fuel mixture entering the cylinder, based on driver input from the accelerator.
    • The venturi creates a low-pressure area over the jet, causing fuel to spray into the air stream.

    Operation of Electronic Fuel Injection System in a Spark Ignition Engine (Petrol Engine)

    • Electronic fuel injection systems provide a more even and consistent ignition.
    • Fuel is injected directly into the cylinders, with the injection timing and amount being controlled by the engine control unit (ECU).
    • This system allows for better fuel efficiency and reduced emissions, compared to carburetors.
    • The air-fuel ratio (AFR) is important for achieving optimal performance and reducing pollution.
    • An ideal AFR of 12:1 maximizes engine power but should be adjusted for different driving levels.

    Single Point Injection

    • Fuel injectors are usually mounted centrally in a throttle body.
    • Fuel is directly sprayed into the throttle bore, eliminating parts associated with fuel metering and jet control.
    • Sensors typically monitor temperature, crankshaft position, air intake, coolant temperature for optimal performance.
    • Actuators, like fuel injectors, operate automatically and are adjusted based on input data.

    Multipoint Injection

    • One injector is used per cylinder.
    • Fuel is injected directly into the combustion chamber for each cylinder to enable precise control of individual injector functions.
    • Sensors and actuators regulate fuel flow for each cylinder to achieve efficient fuel usage.

    Magneto Ignition System

    • Used in smaller petrol engines, such as motorcycles and aircraft.
    • Uses permanent magnets to generate electricity without needing an external power supply.
    • The flywheel produces an electromagnetic field that generates alternating current in the coil, which generates the spark.

    Coil Ignition System

    • Uses a coil to convert low-voltage power from a battery into high-voltage power to create a spark, which will ignite the air-fuel mixture in the engine's cylinders.
    • Components such as battery, ignition coil, contact breaker points, condenser, distributor, and spark plugs are core to the system.
    • A critical part is the contact breaker, which opens and closes regularly. In the primary circuit, the primary winding is wound around a soft iron core, with the secondary winding being wound on top of the primary in a laminated core. The condenser is important in suppressing high-voltage arcing at the breaker points.

    Electronic Ignition System

    • More precise and reliable compared to magneto and coil ignition systems.
    • The electronic control module (ECU) controls timing and quantity of the spark, offering reliable and efficient spark adjustments, based on input from various sensors.
    • Sensors monitoring variables like crankshaft speed and position are crucial in the overall process. The ECU uses these signals for adjustments based on the different driving conditions.

    Distributorless Ignition System

    • The system eliminates the distributor by using coils or coil packs for each cylinder in the engine.
    • This approach increases efficiency and reliability while reducing engine wear.
    • Sensors, like the crankshaft and camshaft position sensors, constantly assess engine speed and position, feeding this data to the ignition control module (ICM) that is responsible for calculating optimal spark timing.

    Automobile Cooling System

    • The cooling system removes excess heat from the engine to prevent overheating.
    • This is important for engine function.
    • Water cooling is common, using water pumped through jackets around the engine to carry heat away - then cooled by the radiator.
    • Thermostatic valves help regulate water flow through the engine, adjusting flow when needed.

    Air Cooling System

    • Air cooling uses air as the cooling medium, through fins or heat exchangers, providing cooling to the engine components.
    • Air cooling is simpler and less expensive than water cooling, but is less effective in some applications.

    Automobile Engine Lubrication System

    • Lubrication prevents wear and tear on engine components.
    • Viscosity is an important measure of lubrication oil.
    • Components like oil filters, pumps, and sensors contribute to the proper operation.
    • Oil is circulated through the engine, flowing from the sump through component bearings, and then returning to the sump.
    • Two types of lubrication systems are in use: partial flow and full flow.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    STT 231 Notes - PDF

    Description

    Test your knowledge of engine ignition and fuel systems with this comprehensive quiz. Explore topics such as choke functions, electronic fuel injection, air-fuel ratios, and the roles of various components like the ECU and sensors. Perfect for automotive students and enthusiasts looking to deepen their understanding of engine mechanics.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser