Write short note on.testing of ic engine as per is
Answers
Answered by
0
Engine performance is an indication of the degree of success of the engine performs its
assigned task, i.e. the conversion of the chemical energy contained in the fuel into the
useful mechanical work. The performance of an engine is evaluated on the basis of the
following :
(a) Specific Fuel Consumption.
(b) Brake Mean Effective Pressure.
(c) Specific Power Output.
(d) Specific Weight.
(e) Exhaust Smoke and Other Emissions.
The particular application of the engine decides the relative importance of these
performance parameters.
For Example : For an aircraft engine specific weight is more important whereas for an
industrial engine specific fuel consumption is more important.
For the evaluation of an engine performance few more parameters are chosen and the
effect of various operating conditions, design concepts and modifications on these
parameters are studied. The basic performance parameters are the following :
(a) Power and Mechanical Efficiency.
(b) Mean Effective Pressure and Torque.
(c) Specific Output.
(d) Volumetric Efficiency.
(e) Fuel-air Ratio.
(f) Specific Fuel Consumption.
(g) Thermal Efficiency and Heat Balance.
(h) Exhaust Smoke and Other Emissions.
(i) Specific Weight.
Power and Mechanical Efficiency
The main purpose of running an engine is to obtain mechanical power.
• Power is defined as the rate of doing work and is equal to the product
of force and linear velocity or the product of torque and angular
velocity.
• Thus, the measurement of power involves the measurement of force
(or torque) as well as speed. The force or torque is measured with the
help of a dynamometer and the speed by a tachometer.
The power developed by an engine and measured at the output shaft is called the
brake power (bp) and is given by,
2
60
π
=
NT bp . . . (7.1)
where, T is torque in N-m and N is the rotational speed in revolutions per minute.
The total power developed by combustion of fuel in the combustion chamber is,
however, more than the bp and is called indicated power (ip). Of the power
developed by the engine, i.e. ip, some power is consumed in overcoming the
friction between moving parts, some in the process of inducting the air and
removing the products of combustion from the engine combustion chamber.
assigned task, i.e. the conversion of the chemical energy contained in the fuel into the
useful mechanical work. The performance of an engine is evaluated on the basis of the
following :
(a) Specific Fuel Consumption.
(b) Brake Mean Effective Pressure.
(c) Specific Power Output.
(d) Specific Weight.
(e) Exhaust Smoke and Other Emissions.
The particular application of the engine decides the relative importance of these
performance parameters.
For Example : For an aircraft engine specific weight is more important whereas for an
industrial engine specific fuel consumption is more important.
For the evaluation of an engine performance few more parameters are chosen and the
effect of various operating conditions, design concepts and modifications on these
parameters are studied. The basic performance parameters are the following :
(a) Power and Mechanical Efficiency.
(b) Mean Effective Pressure and Torque.
(c) Specific Output.
(d) Volumetric Efficiency.
(e) Fuel-air Ratio.
(f) Specific Fuel Consumption.
(g) Thermal Efficiency and Heat Balance.
(h) Exhaust Smoke and Other Emissions.
(i) Specific Weight.
Power and Mechanical Efficiency
The main purpose of running an engine is to obtain mechanical power.
• Power is defined as the rate of doing work and is equal to the product
of force and linear velocity or the product of torque and angular
velocity.
• Thus, the measurement of power involves the measurement of force
(or torque) as well as speed. The force or torque is measured with the
help of a dynamometer and the speed by a tachometer.
The power developed by an engine and measured at the output shaft is called the
brake power (bp) and is given by,
2
60
π
=
NT bp . . . (7.1)
where, T is torque in N-m and N is the rotational speed in revolutions per minute.
The total power developed by combustion of fuel in the combustion chamber is,
however, more than the bp and is called indicated power (ip). Of the power
developed by the engine, i.e. ip, some power is consumed in overcoming the
friction between moving parts, some in the process of inducting the air and
removing the products of combustion from the engine combustion chamber.
Similar questions