internal-combustion engine (noun)

1. As they drove through the countryside in their vintage convertible, the sound of the internal-combustion engine added a romantic touch to their anniversary getaway.

2. In the animated series, the villain's secret weapon was an internal-combustion engine that powered his flying machine.

3. The protagonist in the novel was fascinated by the mechanics of the internal-combustion engine and often referenced it as a symbol of human innovation.

4. The religious ceremony took place in a peaceful garden, where the only sound heard was the soft hum of the internal-combustion engine of a nearby generator.