ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel
  • »
  • Travel and Places»
  • Travel Transportation

Irregularities in Indicator Diagram

Updated on July 20, 2013

Irregularities in the shape of indicator diagrams are indications of faulty engine operations. If irregularity seems for all units, problem may be common like faults in fuel oil system, intake air, turbocharger, air cooler, exhaust, etc. When the irregularity is confined to a single unit, problem could be of fuel injectors, fuel pump, exhaust valve, etc.

Early Ignition

Indications and Effects

  • Abnormally high peak pressure of the unit is recorded at the top of the piston stroke.
  • Knocking sound comes out of the engine due to heavy loads passed to bearings via running gear.
  • Early ignition causes increased thermal efficiency of the engine. Also exhaust temperature reduces since combustion starts long before it is supposed to. But the shock loads and vibrations results in damage of the engine.

Causes

  • Incorrectly adjusted or accidently changed fuel pump timing
  • Damaged or incorrectly set fuel valve or fuel injector
  • Undesired fuel quality
  • Parts inside the cylinder are overheated.

Early Ignition
Early Ignition

Late Ignition

Indications and Effects

  • Low peak pressure is indicated for the unit after top dead center.
  • Combustion continue during expansion stroke, give rise to incomplete combustion of fuel, loss of energy, elevated exhaust gas temperature for the unit, and black smoke at the engine exhaust.
  • Reduced power of the engine due to incomplete combustion of the fuel and energy lost in the exhaust.

Causes

  • Faulty fuel injector or injector spring tension tighted beyond setting.
  • Poor fuel quality
  • Wrongly timed or leaking fuel pump
  • Engine parts inside cylinder are under cooled
  • Incorrect atomization
  • Compression pressure low
  • Combustion air supply is low


Late Ignition
Late Ignition

After Burning

Indication and Effects

  • A rise in expansions line is recorded in the later part of piston stroke
  • Since burning of fuel continues, exhaust gas temperature and pressure increases, causing black smoke at engine exhaust.
  • Unburnt carbon deposits fouls exhaust system, cause damage to exhaust valve and seat, turbocharger surges and there are chances of uptake fires in exhaust gas economizer.
  • Elevated temperatures inside cylinders cause breaking up of lubrication and increased wear of liners, piston rings, burning of piston crown, etc.

Causes

  • Slow fuel combustion
  • Quality of fuel is less
  • Low temperature of fuel (Means high viscosity)

After Burning
After Burning

Leaky Fuel Injector

Indications and Effects

  • Reduced power in the affected unit, high exhaust temperature and presence of black smoke in exhaust.
  • Possible knocking sounds or pressure waves in fuel injection system.
  • Sudden up and downs in indicated diagram in the fuel injection and expansion side.
  • After burning due to incomplete combustion of fuel.

Causes

  • Leaking fuel injector.
  • Chocking of fuel injector spray holes, which leads to improper atomization and dripping of fuel.

Leaky Fuel Injector
Leaky Fuel Injector

Partly Choked Fuel Valve

Indications and Effects

  • Low exhaust gas temperature of the unit
  • Power card and draw card indications
  • Loss of engine power

Causes

  • Fuel oil contamination and improper purification
  • Carbon formation at injector tip
  • Carbon deposits on fuel valve due to over heating

Partly Choked Fuel Valve
Partly Choked Fuel Valve

Low Compression

Indications and Effects

  • Low pressure in the indicator card
  • Reduced power of engine

Causes

  • Improper combustion
  • Insufficient air for combustion
  • Leakage of air in between piston rings and liner while compression stroke due to worn out liner or piston rings.

Low Compression
Low Compression

Exhaust Valve Opening

Light spring diagram gives indications on faulty exhaust valve and intake port operations.

Early Opening

  • Elevated exhaust gas temperature and fouling of exhaust system
  • Loss of engine power

Late Opening

  • Reduced blow down effect and hence reduced scavenging efficiency
  • Low quality of exhaust gas delivered to the turbocharger inversely affect its operation

Exhaust Valve Opening
Exhaust Valve Opening

Choked Exhaust

Indications and Effects

  • Power loss in the unit
  • Increased exhaust temperature
  • Turbocharger surging
  • adversely affect scavenging efficiency

Causes

  • Improper combustion
  • Increased cylinder lube oil

Choked Exhaust
Choked Exhaust

Comments

    0 of 8192 characters used
    Post Comment

    • profile image

      Tama 3 years ago

      I want to say Honda XR250, as the cam cover and rocker caps, cltcuh arm and cltcuh casing would match, but not sure about the shaped trim cover over the oil filter.

    • Haseena Firdousia profile image

      Haseena 4 years ago from India

      Greta hub. Voted up.

    • profile image

      Alex 5 years ago

      first time reading about indicator diagrams. good

    working

    This website uses cookies

    As a user in the EEA, your approval is needed on a few things. To provide a better website experience, hubpages.com uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

    For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at: "https://hubpages.com/privacy-policy#gdpr"

    Show Details
    Necessary
    HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
    LoginThis is necessary to sign in to the HubPages Service.
    Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
    AkismetThis is used to detect comment spam. (Privacy Policy)
    HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
    HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
    Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
    CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
    Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the googleapis.com or gstatic.com domains, for performance and efficiency reasons. (Privacy Policy)
    Features
    Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
    Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
    Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
    Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
    Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
    VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
    PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
    Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
    MavenThis supports the Maven widget and search functionality. (Privacy Policy)
    Marketing
    Google AdSenseThis is an ad network. (Privacy Policy)
    Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
    Index ExchangeThis is an ad network. (Privacy Policy)
    SovrnThis is an ad network. (Privacy Policy)
    Facebook AdsThis is an ad network. (Privacy Policy)
    Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
    AppNexusThis is an ad network. (Privacy Policy)
    OpenxThis is an ad network. (Privacy Policy)
    Rubicon ProjectThis is an ad network. (Privacy Policy)
    TripleLiftThis is an ad network. (Privacy Policy)
    Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
    Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
    Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
    Statistics
    Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
    ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
    Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)