Renault have promised Fernando Alonso the most reliable engine they can come up with for the Brazilian Grand Prix.
Alonso has not seen eye-to-eye with his team in recent weeks
Alonso needs a single point to retain his title while Ferrari's Michael Schumacher must win and see his rival fail to score to take an eighth crown.
Renault F1 engine boss Denis Chevrier said: "It is obvious our technical approach will not be the same as usual.
"We are not going to be looking for that final tenth (of a second) at Interlagos on 22 October."
Chevrier added: "Fernando is not going to give up a chance to win if he sees that it is possible.
"Nevertheless, his objectives in Brazil will be different."
Alonso capitalised on a rare engine failure in Schumacher's Ferrari to win Sunday's Japanese GP.
But the Renault driver suffered a breakdown of his own at Monza in the Italian GP, and his team are anxious to avoid a repeat.
Chevrier said: "Renault will not revert to a tried and tested old-spec V8, which would compromise competitiveness.
"Instead, we will work on making our current motor fully efficient."
Renault are also nine points ahead of Ferrari in the constructors' championship.
A 10-point haul from the final race of the season will guarantee their second crown in two years.