Cosworth has played down rumours that Lotus is set to switch to Renault power for the 2011 season.
Recently, the British independent engine maker also played down speculation Williams could change suppliers, insisting the team last year signed a three-year contract.
But Germany’s Auto Motor und Sport reports that, like Williams, Lotus has also been disappointed with Cosworth’s 2010 engine, including driveability issues and performance degradation.
"With Lotus, as with all the new teams, we have a three-year contract," Cosworth’s business director Mark Gallagher said in Valencia.
He said he has spoken with Lotus team owner Tony Fernandes about the rumours.
"He told me that they were contacted by all three of the engine companies," said Gallagher, referring to Renault, Ferrari and Mercedes.
"That is the reward for being the best of the new teams," he added. "He (Fernandes) told us that for next season, they are planning (to be) with us."