A new version of the Piper Archer TX is being introduced to the trainer market that has a new Continental branded IO-370 in it. It's a Lycoming engine. How is Continental able to compete against Lycoming with Lycoming's own engine design and Lycoming is silent on the matter. The aviation press has not revealed any legal matters ongoing between them that I am aware of.

I'm aware that Continental acquired ECI/Titan engines who were making aftermarket components that fit Lycoming engines but how could that allow them to build and sell Lycoming "clones" without a fight?

I'm not a lawyer, but a few years ago a Chinese company announced that they were going to build 1956 Ford Thunderbirds and 1965 Mustangs for sale in the US. Ford could not stop them because the copyrights were expired, but the program fell apart because the cars would not pass current safety standards. This may be a similar case, copyright has expired, anyone can make them now.