Answered Questions

  • Octane Number and Cetane Number

    What is the octane number of gasoline and cetane number of diesel used in India?

    pradeep

    • Sep 11th, 2011

    Cetane No. Diesel - 45 to 55

    Octane No. Petrol - 80 to 85

    bijuvh

    • Oct 25th, 2009

    The higher the octane rating, the slower the fuel burns. High-performance engines typically have higher compression ratios (and hence longer piston strokes) which requires higher octane (slow burning)...

  • Pump and Air Compressor Bearings

    Name the different types of Bearing?what type of bearing used in Pumps?What type of bearing used in Air compressor?

  • Frictional Force

    What is the difference between tractive force and frictional force? Which one drives the vehicle? What are the directions of the forces with respect to the wheel?

    NSK7777

    • Aug 25th, 2009

    Thanks for your reply, but I have a small doubt.Now consider a drive wheel rotating in a dry surface and other one on a icy surface.Slip do not occur in the first one because traction force is les...

  • Energy Required to Break a Material

    What is the energy required to break the material is called as?

    Bhargav

    • Jan 29th, 2016

    A material withstands upto its shear stress. Beyond that, impact energy breaks the material.

    S.Biswas

    • Dec 27th, 2015

    Energy required to break a material is specified as the modulus of toughness of that material.

  • Rotating Objects

    Why do objects rotating with more speed appearing to be stationary and sometimes appearing as rotating in the opposite direction?

  • Black Tyres

    Why tyres are ever made black?

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    bhargavmech  

    • Member Since Jul-2009 | Aug 6th, 2009


    When Tyres are parked for extended periods, tires dry out, discolor and eventually crack and split. The major factor degrading tires and other synthetic and rubber products is ozone, an odorless gas which is part of the air we breath. When combined with ultraviolet light (the invisible part of sunlight) a reaction occurs that attacks the tire polymer. To protect against ozone and UV damage, a stabilizer molecule called a “competitive absorber” is blended with the tire polymer. Competitive absorbers work by capturing and absorbing UV radiation and converting it to heat which is dissipated harmlessly. All tire manufacturers use the same competitive absorber, carbon black. This is why all tires are black

  • Carnot Engine Efficiency

    What is maximum efficiency of Carnot Engine?

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    bhargavmech  

    • Member Since Jul-2009 | Aug 1st, 2009


    The maximum efficiency of the carnot engine only depends on two factors:

    1 - The temperature of the hot reservoir (TH)
    2 - The temperature of the cold reservoir (TC)

    And is given by (TH - TC) / TH « or » 1 - TC / TH So by that we can see the maximum efficiency (100%) would be when the difference of temperatures between the two reservoirs is infinite.

    sagar jain

    • Apr 5th, 2016

    In carnot engine, working fluid is ideal gas. The only possiblity that the efficiency of carnot engine to be 100% is when the temperature of reservoir comes to absolute zero.

    Rakesh Sharma

    • May 24th, 2014

    There is not any even a single cycle having efficiency higher than the carnot cycle efficiency it means carnot engine having 100% efficiency.

  • Railway Engine Motor

    What motor do they use in railway engines for traction?

    hemalshah94

    • Aug 27th, 2010

    In Local memu train, series motor is used bec it  requires high torque initially e.g. Anand Memu, Vadodara memuIn Express train, I.M motor or Shunt motor is used bec. it requires high torque as well as constant speed e.g Ashram Express

  • Speed and Torque

    What is the practical difference Speed and Torque?

    shank

    • Dec 7th, 2013

    The first cyclist gives his force alone but, the second cyclist gives his force with addition to the rider behind him.so, the second cyclist have the tendency to give more torque than first cyclist.

  • Elasticity

    Which is more elastic - Steel or Rubber?

    Pankaj

    • Oct 31st, 2012

    Elasticity is the property by virtue of which body regain its original shape and size after removal of external force.

    LDK

    • Oct 29th, 2012

    Steel have a more elasticity then any other material

  • What does DTSFI mean? Which is used in automobile engine section?

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    bhargavmech  

    • Member Since Jul-2009 | Jul 31st, 2009


    DTS-Fi stands for "Digital Twin Spark Fuel Injection", a ‘Bajaj Patented Technology’. In fuel injection, the conventional carburettor has been replaced by injector which injects fuel in to the engine in a spray form based on the instructions of the Engine Control Unit (ECU) which is a part of the Engine Management System EMS. The Electronic Control Unit (ECU) is microprocessor based and is the brain of the fuel injection system. It processes information sent by various sensors and instantly determines optimum fuelling and spark timing for various engine-operating conditions. The ECU contains detailed information of the engine's characteristics from which it picks the necessary data for commanding both fuelling & spark timing.

    The main advantages of Fuel Injection are: a. Increased power output for same cc. b. Better low-end torque. c. Lower fuel delivery & optimisation of spark timing. d. Improved cold start, quick warm-up and excellent response to sudden acceleration. e. Lower emission levels. f. Self-detection and communication of fuel system malfunctioning if any.

    Gambit

    • Jul 18th, 2009

    DTSFI means Digital Twin Spark Fuel Injection. The engine using this technology will use 2 spark plugs which will ensure better combustion of fuel and hence better fuel economy and less pollution.