Mechanical Engineering Exam  >  Mechanical Engineering Questions  >  A vehicle powered by a spark ignition engine ... Start Learning for Free
A vehicle powered by a spark ignition engine follows air standard Otto cycle (γ = 1.4 .) The engine generates 70 kW while consuming 10.3 kg/hr of fuel. The calorific value of fuel is 44,000 kJ/kg. The compression ratio is __________ (correct to two decimal places). Answer: 7.61
    Correct answer is '7.61'. Can you explain this answer?
    Verified Answer
    A vehicle powered by a spark ignition engine follows air standard Otto...
    Amount of heat supplied per second= 10.3×44000/3600 kJ/s
    =125.88kW
    View all questions of this test
    Most Upvoted Answer
    A vehicle powered by a spark ignition engine follows air standard Otto...
    Four-stroke cycle). The compression ratio of the engine is 10:1 and the maximum temperature in the cycle is 2000°C. The specific heat ratio (γ) of the working fluid is 1.4. Determine the following:

    a) The cut-off ratio
    b) The maximum pressure in the cycle
    c) The heat rejection during the exhaust stroke
    d) The thermal efficiency of the cycle

    To solve this problem, we can use the following equations for the Otto cycle:

    1) Cut-off ratio (r_c):
    r_c = V_3 / V_2

    2) Maximum pressure (P_max):
    P_max = P_3 = P_4

    3) Heat rejection during exhaust stroke (Q_reject):
    Q_reject = C_v * (T_4 - T_1)

    4) Thermal efficiency (η):
    η = 1 - (1 / r_c^(γ-1))

    Where:
    V_1 = Volume at the beginning of the compression stroke
    V_2 = Volume at the end of the compression stroke (beginning of the power stroke)
    V_3 = Volume at the end of the power stroke (beginning of the exhaust stroke)
    V_4 = Volume at the end of the exhaust stroke (beginning of the intake stroke)
    P_1 = Pressure at the beginning of the compression stroke
    P_2 = Pressure at the end of the compression stroke (beginning of the power stroke)
    P_3 = Pressure at the end of the power stroke (beginning of the exhaust stroke)
    P_4 = Pressure at the end of the exhaust stroke (beginning of the intake stroke)
    T_1 = Temperature at the beginning of the compression stroke
    T_2 = Temperature at the end of the compression stroke (beginning of the power stroke)
    T_3 = Temperature at the end of the power stroke (beginning of the exhaust stroke)
    T_4 = Temperature at the end of the exhaust stroke (beginning of the intake stroke)
    C_v = Specific heat at constant volume

    Now let's calculate the values:

    a) The cut-off ratio:
    r_c = V_3 / V_2
    Since it is an air standard cycle, the volumes are related to the compression ratio (r) as follows:
    r = V_1 / V_2
    r_c = r^(1/γ)
    r_c = (10)^(1/1.4)
    r_c ≈ 4.6416

    b) The maximum pressure in the cycle:
    P_max = P_3 = P_4
    Since it is an air standard cycle, the pressures are related to the compression ratio (r) as follows:
    r = (V_1 / V_2) = (P_1 / P_2)^(1/γ)
    P_max = P_1 / r^(γ)
    P_max = P_1 / (10)^(1/1.4)

    c) The heat rejection during the exhaust stroke:
    Q_reject = C_v * (T_4 - T_1)
    Since it is an air standard cycle, the temperatures are related to the compression ratio (r) as follows:
    r = (V_1 / V_2) = (T_1 / T_2)^(γ-1)
    T_4 = T_1 / r^(γ-1)
    Q_reject = C_v *
    Attention Mechanical Engineering Students!
    To make sure you are not studying endlessly, EduRev has designed Mechanical Engineering study material, with Structured Courses, Videos, & Test Series. Plus get personalized analysis, doubt solving and improvement plans to achieve a great score in Mechanical Engineering.
    Explore Courses for Mechanical Engineering exam

    Top Courses for Mechanical Engineering

    A vehicle powered by a spark ignition engine follows air standard Otto cycle (γ = 1.4 .) The engine generates 70 kW while consuming 10.3 kg/hr of fuel. The calorific value of fuel is 44,000 kJ/kg. The compression ratio is __________ (correct to two decimal places). Answer: 7.61Correct answer is '7.61'. Can you explain this answer?
    Question Description
    A vehicle powered by a spark ignition engine follows air standard Otto cycle (γ = 1.4 .) The engine generates 70 kW while consuming 10.3 kg/hr of fuel. The calorific value of fuel is 44,000 kJ/kg. The compression ratio is __________ (correct to two decimal places). Answer: 7.61Correct answer is '7.61'. Can you explain this answer? for Mechanical Engineering 2024 is part of Mechanical Engineering preparation. The Question and answers have been prepared according to the Mechanical Engineering exam syllabus. Information about A vehicle powered by a spark ignition engine follows air standard Otto cycle (γ = 1.4 .) The engine generates 70 kW while consuming 10.3 kg/hr of fuel. The calorific value of fuel is 44,000 kJ/kg. The compression ratio is __________ (correct to two decimal places). Answer: 7.61Correct answer is '7.61'. Can you explain this answer? covers all topics & solutions for Mechanical Engineering 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A vehicle powered by a spark ignition engine follows air standard Otto cycle (γ = 1.4 .) The engine generates 70 kW while consuming 10.3 kg/hr of fuel. The calorific value of fuel is 44,000 kJ/kg. The compression ratio is __________ (correct to two decimal places). Answer: 7.61Correct answer is '7.61'. Can you explain this answer?.
    Solutions for A vehicle powered by a spark ignition engine follows air standard Otto cycle (γ = 1.4 .) The engine generates 70 kW while consuming 10.3 kg/hr of fuel. The calorific value of fuel is 44,000 kJ/kg. The compression ratio is __________ (correct to two decimal places). Answer: 7.61Correct answer is '7.61'. Can you explain this answer? in English & in Hindi are available as part of our courses for Mechanical Engineering. Download more important topics, notes, lectures and mock test series for Mechanical Engineering Exam by signing up for free.
    Here you can find the meaning of A vehicle powered by a spark ignition engine follows air standard Otto cycle (γ = 1.4 .) The engine generates 70 kW while consuming 10.3 kg/hr of fuel. The calorific value of fuel is 44,000 kJ/kg. The compression ratio is __________ (correct to two decimal places). Answer: 7.61Correct answer is '7.61'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of A vehicle powered by a spark ignition engine follows air standard Otto cycle (γ = 1.4 .) The engine generates 70 kW while consuming 10.3 kg/hr of fuel. The calorific value of fuel is 44,000 kJ/kg. The compression ratio is __________ (correct to two decimal places). Answer: 7.61Correct answer is '7.61'. Can you explain this answer?, a detailed solution for A vehicle powered by a spark ignition engine follows air standard Otto cycle (γ = 1.4 .) The engine generates 70 kW while consuming 10.3 kg/hr of fuel. The calorific value of fuel is 44,000 kJ/kg. The compression ratio is __________ (correct to two decimal places). Answer: 7.61Correct answer is '7.61'. Can you explain this answer? has been provided alongside types of A vehicle powered by a spark ignition engine follows air standard Otto cycle (γ = 1.4 .) The engine generates 70 kW while consuming 10.3 kg/hr of fuel. The calorific value of fuel is 44,000 kJ/kg. The compression ratio is __________ (correct to two decimal places). Answer: 7.61Correct answer is '7.61'. Can you explain this answer? theory, EduRev gives you an ample number of questions to practice A vehicle powered by a spark ignition engine follows air standard Otto cycle (γ = 1.4 .) The engine generates 70 kW while consuming 10.3 kg/hr of fuel. The calorific value of fuel is 44,000 kJ/kg. The compression ratio is __________ (correct to two decimal places). Answer: 7.61Correct answer is '7.61'. Can you explain this answer? tests, examples and also practice Mechanical Engineering tests.
    Explore Courses for Mechanical Engineering exam

    Top Courses for Mechanical Engineering

    Explore Courses
    Signup for Free!
    Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
    10M+ students study on EduRev