Modern Engineering Thermodynamics

516 CHAPTER 13: Vapor and Gas Power Cycles
NO LIGHT ON DIESEL’S FATE
Special Cable to The New York Times
LONDON, Oct.2.—The mystery of the disappearance on Monday night of Dr. Rudolf Diesel on the cross-channel steamer
Dresden is still unexplained. A report that Dr. Diesel did not sail on the Dresden receives no confirmation. The inventor was
seen on deck after the vessel left Flushing.
The British Board of Trade inquiry has elicited nothing, and an examination of Dr. Diesel’s private papers at Munich has
been equally without result.
Baron Schmidt, Dr. Diesel’s son-in-law, declares that the theory of suicide in a sudden fit of aberration is entirely
unsupported.
When the inventor went to see his daughter at Frankfurt after several days’ shooting in the Bavarian highlands he
complained that he had overstrained himself and that this had accentuated the weakness of the heart from which he had
suffered in recent years. Nevertheless, he was in the best possible spirits.
DIESEL WAS BANKRUPT
He Owed $375,000—Tangible Assets Only about $10,000
By Marconi Transatlantic Wireless Telegraph to The New York Times
MUNICH, Oct.14.—The deplorable state of the late Dr. Rudolf Diesel’s finances was revealed at today’s meeting of his
creditors here.
The meeting found itself unable to take definite action regarding the administration of Dr. Diesel’s wrecked fortune, as the
exact state of affairs remains to be cleared up. It is declared that the inventor’s liabilities are approximately $375,000,
against which the tangible assets are only $10,000.
Figures laid before the meeting showed a state of confusion in the tabulation of Dr. Diesel’s supposed assets. In the case of
some houses at Hamburg and Munich it was found that there was an overvaluation of $125,000.
Diesel cycle engines operate with a much higher compression ratio than Otto cycle engines (12 to 24 vs. 8 to 11)
and therefore are more efficient than Otto cycle engines. Typical Otto cycle engine actual thermal efficiencies are
in the range from 15 to 25%, whereas for Diesel cycle engines, they normally fall in the range from 30 to 45%. As
the previous example illustrates, very large Diesel engines can have efficiencies greater than 50%.
Because combustion takes place intermittently in internal combustion engines and therefore the cylinder is
alternately heated by combustion and cooled by the intake stroke (plus the fact that most of these engines have
water jacket cooling), they have the same heat transfer irreversibilities as the early 18th century Newcomen
steam engines. A similar cyclic cylinder heating and cooling process in the Newcomen steam engine led James
Watt to develop the external steam condenser that improved the engine’s thermal efficiency fourfold.
13.22 MODERN PRIME MOVER DEVELOPMENTS
Solving for the power from an energy rate balance (ERB) on a steady state, steady flow, single-inlet, single-outlet
prime mover (neglecting any changes in kinetic or potential energy) yields
_W out = _mðh in − h out Þ − j _Qj loss
Since the primary objective of any prime mover is to produce power ð _W out > 0Þ, anyheatlossðj_Qj loss > 0Þ
clearly reduces both the power output and the thermal efficiency of the prime mover. Consequently, most
external combustion prime movers are heavily insulated to minimize their heat loss and maximize their thermal
efficiency. When there is no heat loss or gain by a prime mover, it can properly be called an adiabatic
prime mover.