I’ve mentioned here before some instances in which current technical problems have sometimes been amenable to old technologies, dusted off and updated a bit. For example, there is the use of the venerable AC induction motor, patented by Nikola Tesla in 1888, in new electric vehicles, as well as the renewed interest in the use of DC power distribution for data centers.
Now, according to an article at Technology Review, another old technology, for a type of Diesel engine, is getting another look. The basic design, called the Jumo engine, was originated back in the 1930s by Junkers, a German aircraft manufacturer. It was dirty, but very efficient. In contrast to a conventional Diesel engine, which uses a single piston per cylinder to compress air and fuel, the Jumo engine uses two pistons per cylinder, compressing the air-fuel mixture between them. The efficiency advantage arises from expending less energy heating up the cylinder head, leaving more to drive the pistons.
A California company called Achates Power has updated the engine design to allow it to meet current emission standards, at least in a one-cylinder prototype. The US Army has given Achates, together with a partner company, AVL Powertrain Engineering, a $4.9 million grant to develop a multi-cylinder prototype. The company believes that the engine can be made smaller and cheaper than existing Diesel engines, while boosting fuel economy by 20%. Compared to a gasoline engine, the fuel economy would of course look even better.
This is still a prototype, and the new design is not likely to make the 2014 model year for new cars. Still, it is encouraging that progress can be made without requiring a “great leap forward” in every instance.