LONDON, July 10 (Reuters) - Some of the world's biggest carmakers on Friday largely won the first stage of a major legal battle over claims that their diesel vehicles were fitted with unlawful "defeat devices" to curtail emissions controls.
In a summary of her judgment, Judge Sara Cockerill said she had "rejected most of the principal allegations advanced against the manufacturers whose vehicles were examined at trial".
She said that a defeat device under emissions regulation only covered "devices
which operate with the intentional and/or impermissible purpose of causing the (emissions control system) to operate differently when it senses the test cycle".
The case centred on 20 sample vehicles made by Mercedes-Benz, Ford, Nissan, Renault and the Stellantis-owned brands Peugeot and Citroen.
Cockerill did make some adverse findings, including over a coolant temperature device used in some Mercedes cars that was removed in a December 2015 update.
However, she said the device did not reduce the effectiveness of the emissions control system.
A Mercedes-Benz spokesperson welcomed the ruling, saying the court had found "very largely in favour" of the company. The automaker said it disagreed with the adverse finding and was considering its options, including a possible appeal.
Lawyers representing the claimants said they were considering a possible appeal against Friday's ruling, which they said "adopted a significantly narrower interpretation of the law than that applied elsewhere in Europe".
The trial, which began in October, was the most significant hearing to date in 13 groups of lawsuits brought by around 1.6 million claimants.
Friday's ruling concerned test cases against five manufacturers but will also apply to roughly 800,000 similar claims involving other carmakers.
A further trial is due to begin in October to determine the consequences of any breaches of emissions rules and whether any claimants are entitled to damages.
The litigation comes more than a decade after Volkswagen's "Dieselgate" scandal, which cost the German automaker billions of euros.
Rival manufacturers have argued that the case is fundamentally different from Volkswagen's emissions-cheating scandal and that emissions control systems may legitimately operate differently under certain conditions.
(Reporting by Sam Tobin. Editing by William James and Mark Potter)
