Final answer:
To allow higher gas temperatures in the turbine section of some engines and increase efficiency, improved engineering and superior materials can be used.
Step-by-step explanation:
The efficiency of a heat engine can be increased by allowing higher gas temperatures in the turbine section. This can be achieved through improved engineering and the use of superior materials. By increasing the temperature of the hot reservoir in a heat engine, the temperature difference between the hot and cold reservoirs becomes greater, resulting in a higher efficiency.