Four-Stroke Engine Basics and Malfunctions
40 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 a characteristic feature of a two-stroke engine compared to a four-stroke engine?

  • It completes the power cycle in one crankshaft revolution. (correct)
  • It produces more power strokes per cycle.
  • It requires more components to operate.
  • It has a longer operational cycle.

    • During which stroke does the piston create a highly combustible environment for ignition?

  • Intake stroke
  • Power stroke
  • Exhaust stroke
  • Compression stroke (correct)

    • What occurs during the exhaust stroke of the engine cycle?

  • The piston expels burned gases from the cylinder. (correct)
  • The intake valve opens to let in new air and fuel.
  • The connecting rod connects the piston to the crankshaft.
  • The spark plug ignites the air-fuel mixture.

    • What is the primary function of the crankshaft in an engine?

    <p>To convert linear motion of the piston into rotational motion.</p> Signup and view all the answers

    What issue can arise if the step of removing burned gases from the cylinder is skipped?

    <p>Fresh air-fuel mixture may be diluted.</p> Signup and view all the answers

    In what application are two-stroke engines commonly favored over four-stroke engines?

    <p>Motorcycles and chainsaws</p> Signup and view all the answers

    What is the function of the piston during the intake stroke?

    <p>To open the intake valve and draw in the mixture.</p> Signup and view all the answers

    How many total strokes are needed in a four-stroke engine for one complete power cycle?

    <p>Four strokes</p> Signup and view all the answers

    What sequence of strokes occurs in a four-stroke engine?

    <p>Intake, compression, power, exhaust</p> Signup and view all the answers

    What happens during the exhaust stroke of a four-stroke engine?

    <p>Burned gases are expelled from the cylinder</p> Signup and view all the answers

    How does a malfunctioning intake valve affect the engine cycle?

    <p>It prevents the fuel-air mixture from entering the cylinder</p> Signup and view all the answers

    What is the role of timing in the exhaust valve operation?

    <p>To allow burnt gases to assist in expelling them</p> Signup and view all the answers

    What could result from improper execution of the exhaust stroke?

    <p>Residual exhaust gases remain in the cylinder</p> Signup and view all the answers

    Why is a four-stroke engine considered efficient?

    <p>It allows for better combustion control and cleaner emissions</p> Signup and view all the answers

    What occurs if residual exhaust gases enter a cylinder during the intake stroke?

    <p>It dilutes the incoming air-fuel mixture</p> Signup and view all the answers

    What is the function of the piston during the intake stroke?

    <p>Drawing in the fuel-air mixture</p> Signup and view all the answers

    What occurs during the Intake Stroke of the Otto Cycle?

    <p>The air and gasoline mixture is drawn into the cylinder.</p> Signup and view all the answers

    What is the function of the Exhaust Stroke?

    <p>To expel waste gases through the exhaust valve.</p> Signup and view all the answers

    How does a malfunctioning intake valve affect engine performance?

    <p>It can lead to rough idling and reduced power output.</p> Signup and view all the answers

    During the Compression Stroke, what happens to the volume and pressure in the cylinder?

    <p>Volume decreases, pressure increases.</p> Signup and view all the answers

    What distinguishes a petrol engine's ignition from a diesel engine's?

    <p>Petrol engines use a spark plug; diesel relies on high compression self-ignition.</p> Signup and view all the answers

    What is the significance of the Bottom Dead Center (BDC) in the engine cycle?

    <p>BDC is the point at which the piston is at its lowest position.</p> Signup and view all the answers

    What is the function of the spark plug in petrol engines?

    <p>To ignite the mixture at the optimal moment.</p> Signup and view all the answers

    What is meant by the compression ratio in an engine?

    <p>The ratio of minimum to maximum cylinder volume.</p> Signup and view all the answers

    What is the primary function of the spark plug in the Otto cycle?

    <p>To ignite the air and gasoline mixture</p> Signup and view all the answers

    What distinguishes diesel engines from petrol engines regarding compression ratios?

    <p>Diesel engines have higher compression ratios.</p> Signup and view all the answers

    Which of the following statements about fuel efficiency is correct?

    <p>Diesel engines are generally more fuel-efficient due to higher compression ratios.</p> Signup and view all the answers

    During which stroke does the spark plug ignite the air-fuel mixture in petrol engines?

    <p>Power stroke</p> Signup and view all the answers

    What is one advantage of diesel engines over petrol engines?

    <p>Higher energy content of the fuel</p> Signup and view all the answers

    How do diesel engines achieve self-ignition?

    <p>Through the higher compression ratios and thermal efficiency</p> Signup and view all the answers

    What happens to the pressure within the cylinder during combustion?

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

    Which of the following characteristics is more prominent in petrol engines compared to diesel engines?

    <p>Spark ignition</p> Signup and view all the answers

    What method do diesel engines use to ignite the air-fuel mixture?

    <p>Higher compression ratios</p> Signup and view all the answers

    What is the compression ratio of the 2015 VW Golf TDI?

    <p>16.2:1</p> Signup and view all the answers

    Which component primarily increases fuel supply in diesel engines?

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

    How do diesel engines compare to petrol engines in terms of fuel efficiency?

    <p>Diesel engines produce approximately 33.7 mega joules per liter.</p> Signup and view all the answers

    Which is a characteristic of the power stroke in diesel engines?

    <p>Combustion ignites and forces the piston down.</p> Signup and view all the answers

    What distinguishes the way petrol engines manage air intake compared to diesel engines?

    <p>Diesel engines lack a throttle body.</p> Signup and view all the answers

    At what RPM do diesel engines typically produce more torque?

    <p>Low RPMs</p> Signup and view all the answers

    What happens during the compression stroke of a diesel engine?

    <p>The piston moves up, compressing the air.</p> Signup and view all the answers

    Study Notes

    Four-Stroke Engine Basics

    • Four Strokes: Intake, Compression, Power, Exhaust
    • Intake Stroke: Piston moves down; intake valve opens; air-fuel mixture enters
    • Compression Stroke: Piston moves up; air-fuel mixture is compressed; creates a combustible environment
    • Power Stroke: Spark plug ignites the mixture; combustion drives the piston down; generates power
    • Exhaust Stroke: Piston moves up; opens exhaust valve; pushes burnt gases out

    Intake Valve Malfunctions

    • Malfunction Prevents Air-Fuel Mixture Entry: Disrupts suction and causes the engine to stall
    • Incomplete Combustion: Can result in engine misfiring or decreased power
    • Exhaust Valve Opens: May expel unburnt fuel, making the engine more inefficient

    Exhaust Stroke Importance

    • Residual Exhaust: Can dilute fresh air-fuel mixture reducing engine efficiency
    • Designed Valve Timing: Opens before BDC, allowing pressure to assist in expulsion

    Two-Stroke vs Four-Stroke Engines

    • Two-Stroke: Single revolution, two strokes, completes cycle quickly; lighter and more compact
    • Four-Stroke: Two revolutions, four strokes, more complex operation, efficient and low emissions
    • Four-Stroke Examples: cars, motorcycles
    • Two-Stroke Examples: motorcycles, chainsaws

    Key Components of a Four-Stroke Engine

    • Piston: Moves up and down in cylinder
    • Connecting Rod: Links piston to crankshaft
    • Crankshaft: Converts linear motion of piston to rotational motion

    Petrol vs Diesel Engines

    • Operation: Both use four-stroke cycle, but ignition methods differ
    • Spark Plug Ignition: Petrol engines ignite the air-fuel mixture with a spark plug
    • Self-Ignition: Diesel engines use high compression to ignite the air-fuel mixture
    • Compression Ratio: Diesel engines have higher compression ratios, typically 16.2:1 compared to petrol 9.6:1
    • Energy Content: Diesel has 15% more energy per volume than petrol
    • Efficiency: Diesel engines are more efficient due to high compression ratio; higher thermal efficiency due to the way combustion happens

    Diesel Engine Components

    • Throttle Mechanism: Diesel engines lack a throttle body; pressing the accelerator increases fuel supply
    • Fuel injectors: Introduce atomized diesel fuel into the high-pressure, high-temperature air

    Diesel Cycle

    • Intake Stroke: Intake valve opens; piston descends and draws in air
    • Compression Stroke: Intake valve closes; piston ascends; compresses air; temperature rises
    • Power Stroke: Fuel injected into highly compressed air; combustion forces piston down; produces power
    • Exhaust Stroke: Piston ascends; expels burnt gases through exhaust valve

    Studying That Suits You

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

    Quiz Team

    Related Documents

    Overview of Two-Stroke Engines PDF

    Description

    Explore the essential components and processes of a four-stroke engine. This quiz covers the four strokes, potential malfunctions related to the intake valve, and the significance of the exhaust stroke. Dive deep into understanding how these elements work together for optimal engine performance.

    More Like This

    Ciclo Otto o Cuatro Tiempos
    10 questions

    Ciclo Otto o Cuatro Tiempos

    BeauteousBanjo avatar
    BeauteousBanjo
    Motores de Dos Tiempos
    48 questions

    Motores de Dos Tiempos

    ExcitedCouplet avatar
    ExcitedCouplet
    Four Stroke Petrol Engine
    5 questions

    Four Stroke Petrol Engine

    FelicitousJasper5718 avatar
    FelicitousJasper5718
    Funktionsweise des 2-Taktmotors
    13 questions

    Funktionsweise des 2-Taktmotors

    CorrectOphicleide1318 avatar
    CorrectOphicleide1318
    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser