How did Rudolf Diesel’s 1897 engine demonstration contribute to the engine’s commercial success?

Rudolf Diesel’s 1897 demonstration of a 25-horsepower, four-stroke, single vertical cylinder compression engine was a pivotal moment that secured the diesel engine’s commercial success.1

The demonstration proved the engine's high efficiency and comparative simplicity of design, which immediately attracted industrial interest. By successfully showcasing a functional model, Diesel validated the theoretical work he had published in 1893, leading to widespread recognition and significant wealth through royalty fees.1

This success allowed for the rapid adoption of the technology, as evidenced by figures like Adolphus Busch, who purchased manufacturing licenses after seeing the engines on display. The engine's ability to operate reliably and economically—utilizing fuel that was safer to store and handle than gasoline—further cemented its role as a primary power plant for critical applications, such as submarines during World War I.2