PRIN. OF INTERNAL COMBUSTION ENGINES - OD1619 LESSON 1/TASK 2
FIGURE 28. COMPARISON OF GASOLINE AND
DIESEL ENGINE REGULATION
OF POWER.
compressing the air. As the piston reaches top dead center, the compression stroke
ends.
(3) Power (figure 29, view C, on the following page). The piston begins the
power stroke at top dead center. At this time, air is compressed in the upper
cylinder to as much as 500 psi (3448kPa). The tremendous pressure in the upper
cylinder brings the temperature of the compressed air to approximately 1000 F
(538 C). The power stroke then begins with the injection of a fuel charge into
the engine. The heat of compression ignites the fuel as it is injected. The
expanding force of the burning gases pushes the piston downward, providing power to
the crankshaft. The power generated in a diesel engine is continuous throughout
the power stroke. This contrasts with a gasoline engine, which has a power stroke
with rapid combustion in the beginning and little or no combustion at the end.
(4) Exhaust (figure 29, view D). As the piston reaches bottom dead center on the
power stroke, the power stroke ends and the exhaust stroke begins. The exhaust
valve opens and the piston pushes the
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