The problem for Toyota is that the patent was filed in the US and a ruling in favor of the Paice company holding the patent can block Toyota/Lexus from having any of their hybrid cars imported to the US because it is a US Patent. This is what the new litigation filed by Paice is attempting to do. An investigation has been launched into the allegations and any ruling is said to be at least 15 months down the road so there is no threat of Toyota hybrids being halted at customs at this time.
Originally, Paice and Toyota agreed on a $4.3 million settlement in 2005 with a $25 per Toyota/Lexus hybrid vehicle produced royalty charge added to that settlement for already produced and future produced vehicles.
I believe this is the text (very lengthy) on the patent that was filed by Paice of which they claim Toyota infringed on.
United States Patent: 7392871