Modern Engineering Thermodynamics

512 CHAPTER 13: Vapor and Gas Power Cycles
EXAMPLE 13.16 (Continued )
State 3 in Figure 13.52b
p 3 = p exhaust = 101 kPa, and since the process from 2s to 3 is a constant volume process, we have T 3 = T 2s (p 3 /p 2s ) = (1760 K)
(101 kPa/901 kPa) = 196 K.
State 4 in Figure 13.52b
p 4 = p 3 = 101 kPa and T 4 = atmospheric temperature.
Exercises
47. Determine the clearance volume in Example 13.16 if the compression ratio is 9.00 to 1 and the expansion ratio is 12.0
to 1. Answer: Clearance volume = 7.96 × 10 –5 m 3 .
48. Determine the pressure and temperature at the end of the compression stroke in Example 13.16 if the supercharger
boost pressure is only 100. kPa instead of 200. kPa. Answer: p 7s =1660 kPa and T 7s = 648 K.
49. If the fuel used in Example 13.16 is changed to a hotter burning fuel with a heating value of 51,700 kJ/kg-fuel,
determine the temperature at the end of the combustion process. Answer: T 1 = 4580 K.
13.21 DIESEL CYCLE
Rudolf Christian Karl Diesel (1858–1913) was a well-educated linguist and social theorist, but most of all, he
was a remarkable engineer. He was born in Paris, but he received his technical education in Munich under Karl
von Linde (1842–1934), a renowned pioneer in mechanical refrigeration.
Though the actual thermal efficiency of Otto’s engine was many times better than that of Lenoir’s, it was still
barely competitive with the ever improving Rankine cycle steam engine. Diesel felt that he could eliminate the
electrical ignition system of the Otto cycle engine if he could compress the air to the point where its temperature
would be high enough to cause the fuel to ignite spontaneously. This would raise the maximum temperature of
the cycle and consequently improve its thermal efficiency. He also felt that a higher combustion temperature
would allow cheaper, heavier hydrocarbon fuels (such as kerosene, a common lamp oil in the late 19th century)
to be used. On August 10, 1893, Diesel’s first compression ignition engine ran under its own power for the first
time, and by 1898, Diesel had become a millionaire simply by selling franchises for the industrial use of his
engine. 11
Diesel had originally intended to create an isothermal combustion process in the cylinder, so as to eliminate the
heat transfer irreversibilities and thus approach the Carnot cycle thermal efficiency. He was not able to do this;
instead, the ASC model of his cycle consists of two isentropic processes (compression and power), one isobaric
process (combustion), and one isochoric process (exhaust), as shown in Figure 13.53.
DR. DIESEL VANISHES FROM A STEAMSHIP
Inventor of Oil Engine Missing after a Journey from Antwerp to Harwich
By Marconi Transatlantic Wireless Telegraph to The New York Times
LONDON, Sept.30.—Dr. Rudolf Diesel, the famous inventor of the Diesel oil engine, has disappeared in most mysterious
circumstances. He left Antwerp yesterday to attend in London the annual meeting of the Consolidated Diesel Engine Manufacturers.
He embarked on the steamer Dresden, accompanied by a fellow Director, George Carels, and Herr Luckmann,
Chief Engineer of the company.
Dr. Diesel had a cabin to himself. On the arrival of the vessel at Harwich at 6 o’clock this morning he was missing. His bed
had not been slept in, though his night attire was laid out on it.
It is conjectured by his friends that Dr. Diesel fell overboard. He complained to a friend some time ago that he was
occasionally troubled with insomnia, and it is possible that when his friends retired to their cabins he decided to continue
11 Diesel’s 1893 test engine compressed air to 80 atm, a pressure never before achieved by a machine. He was nearly killed when the
engine subsequently exploded.