After Diesel's death, engineers continued to refine and improve the Diesel engine. These advancements led to increased efficiency, power, and reliability, making the engine suitable for a wider range of applications. It became a staple in trucks, locomotives, and ships.

Diesel engines played a crucial role in World War II, powering tanks, submarines, and other military vehicles. Their fuel efficiency and robustness made them ideal for these demanding applications.

Diesel engines continued to be developed and refined throughout the late 20th century. However, growing concerns about air pollution and greenhouse gas emissions led to increased scrutiny of diesel technology. Efforts were made to reduce emissions through the development of cleaner diesel fuels and advanced engine technologies.

Modern diesel engines are significantly cleaner and more efficient than their predecessors. Technologies such as common rail injection, turbocharging, and particulate filters have greatly reduced emissions. Diesel-electric hybrid systems are also becoming increasingly popular, combining the benefits of diesel power with electric propulsion.