Sir Harry Ricardo 1885-1974 was knighted for his work improving engines for WWI British tanks. Specifically he reduced the amount of smoke that made them an easy target for German artillery.
The company he founded, Ricardo plc, is still in business after over 100 years. These days they do more than just engine design. They make the software described in the file which is used by engineers to simulate the performance of the engine on a computer before the first prototype is built. They design transmissions and other vehicle systems. They have a rail and a defense division. They designed the braking energy recovery system for Formula 1. They designed and build the engines for McLaren. They make the gearboxes for both the Ford GT and the Bugatti Veyron.