Lesson 2/Learning Event 1
The four-stroke-cycle diesel engine is constructed about the same as the four-stroke-cycle gasoline spark-ignited
engine. The working parts of a diesel engine are made heavier than the gasoline spark-ignited engine. This is
because the diesel engine has much higher cylinder pressures. Early diesel engines were made too heavy for use
in trucks and buses. These heavy diesel engines ran at slow speeds and were used for locomotives, ships
(marine), and power-generating stations.
As time progressed, new metals were developed that were stronger for their weight, and industry soon found it
could build a lighter diesel engine. This lighter diesel engine could run at speeds high enough to work well in
the automotive field.