Question

Let’s begin with an efficiency analysis of a gasoline engine. The engine in a large truck takes in 2500 J of heat and delivers 500 J of mechanical work per cycle. The heat is obtained by burning gasoline with heat of combustion Lc=5.0×104J/g. (a) What is the thermal efficiency of this engine? (b) How much heat is discarded in each cycle? (c) How much gasoline is burned during each cycle? (d) If the engine goes through 100 cycles per second, what is its power output in watts? In horsepower? (e) How much gasoline is burned per second? Per hour?

A gasoline engine with a thermal efficiency of 33 % has a power output of 50 hp. How much heat must be supplied per second to the engine? Express your answer in kilojoules.

Answer #1

A four-cylinder gasoline engine has an efficiency of 0.22 and
delivers 200 J of work per cycle per cylinder. The engine fires at
27 cycles per second.
A) Determine the work done per second.
B) What is the total heat input per second from the
gasoline?
C) If the energy content of gasoline is 150 MJ per gallon, how
long does one gallon last?

A four cylinder gasoline engine has an efficiency of 0.28 and
delivers 200 J of work per cycle per cylinder. The engine fires at
25 cycles per second.
(a) Determine the work done per second.
_____J/s (answer here is not 5000, i've tried it)
(b) What is the total heat input per second from the
gasoline?
_____J/s
(c) If the energy content of gasoline is 130 MJ per gallon, how
long does one gallon last?
_____min

In a certain automobile engine with an efficiency of 21.6%,
combustion of gasoline in one cylinder releases 510 J of heat.
(a) Find the work done by the system of gasoline vapor and air
on the surroundings during one cycle.
(b) Find the total mechanical power produced by all four cylinders,
operating at 48 cycles/s, or 2880 rpm.

35. A heat engine receives heat in the amount of Qh= 775 kJ from
a high thermal reservoir and delivers Wnet= 210 kJ of work per
cycle.
Write an expression for the efficiency of the engine.
What is the efficiency?
Write an expression for the amount of energy required to be
rejected into the low temperature reservoir.
How much energy, in kilojoules, is rejected into the low
temperature reservoir?

A multicylinder gasoline engine in an airplane operates at 2500
revolutions per minute. Each revolution it takes in 7.89 x
103 J and exhausts 4.58 x 103 J.
(a) How many liters of fuel does it consume in 1.0 hour of
operation if the heat of combustion of the fuel is 4.03 x
107 J/L?
(b) What is the mechanical power output of the engine?
(c) What power does the exhaust system transfer out of the
engine?

A particular heat engine has a mechanical power output
of 4.60 kW and an efficiency of 24.0%. The engine expels
6.20 103 J of exhaust energy in each
cycle.
(a) Find the energy taken in during each cycle.
kJ
(b) Find the time interval for each cycle.
s

It is desired to an alyze the performacne of a gas turbine
engine operating on a Bratyon cycle with a free power turbine. The
engine is under test at static conditions with an ambient
temperature of 20'C and pressure of 1atm. The pressure ratio of the
compressor is 5. The engine burnsmethane fuel with a heat of
combustion of 50MJ/kg. The air to fuel ratio (AF) is 45. Assume the
pressure at the inlet to the compressor is equal to...

A local coal fired 200 megawatt electrical generating plant has
a thermal efficiency of 30% and a nuclear 150 megawatt electrical
generating plant has a thermal efficiency of 25%.
a. Calculate the waste heat emitted by each (in megawatts)
b. If the cooling water used for the nuclear plant were required
to only rise in temperature by 2o C after it absorbs the waste
heat, how much water per hour would be required to cool the nuclear
plant (in cubic...

An ideal Otto engine has a compression ratio of 10 and uses air
as the working fluid. The state of air at the beginning of the
compression process is 100 kPa and 27 0C. The maximum
temperature in the cycle is 2100K. (R=0.287 for air) (using
variable specific heat)
Draw the P-v diagram of the Otto cycle
Determine the specific internal energies at the beginning and
the end of the compression,
Determine the specific internal energies before and after the...

1.
You will learn much about heat engine cycles in thermo
II (if you take it), but you already have the basic skills
needed to perform a rst law analysis of a simple vapor
power cycle. This cycle has four basic components: steam
turbine, condenser, liquid pump, and boiler, and four as-
sociated processes. A speci c case of this cycle has water,
in the form of a saturated vapor at 40 kPa, exiting from
the turbine and entering the...

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 38 minutes ago

asked 42 minutes ago

asked 47 minutes ago

asked 56 minutes ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 2 hours ago

asked 2 hours ago

asked 2 hours ago