senor honda

Connecting dots of No. 7 Toyota LM24 clutch failure

Tuesday, 20 June 2017

By Marshall Pruett / Image by Rainier Ehrhardt/LAT

A fishy set of circumstances has been blamed for the clutch failure that took the No. 7 Toyota TS050 HYBRID out of contention for the win at Le Mans last weekend.
Ten hours into the 24-hour contest, polesitter Kamui Kobayashi left the No. 7's pit box after a routine stop under Safety Car conditions. The Japanese driver waited at the end of pit lane, per procedure, and would be sent out onto the racing surface behind the safety car once it motored past the pits.
Algarve Pro Racing driver Vincent Capillaire, whose pit stall was adjacent to where Kobayashi sat in his Toyota, chose to run out and give a quick thumbs-up to the race's dominant performer. Mistaking the Frenchman's thumbs-up for approval to leave the pits, Kobayashi accelerated away under electric power before a radio transmission from the Toyota team instructed him to stop.
Once the safety car went past, Kobayashi departed for the third time and soon found his clutch was malfunctioning. The car would eventually retire after multiple restarts were made throughout the 8.5-mile circuit.
The Toyota Gazoo Racing team has apportioned the blame on Capillaire, whose firesuit bore a strong resemblance to those worn on pit lane by track marshals, for setting the chain reaction in motion.
"Saturday night, during the race ... I wanted to show my encouragement to the leader car, stopped at red light a few meters in front of my box," he said. "It was a spontaneous encouragement mark as it happens between pilots. I was fined by stewards for this gesture and I admit it was inopportune. I'm sorry."

After the race, Toyota Racing technical director Pascal Vasselon attributed the clutch failure to confusion caused by Capillaire, which led Kobayashi to leave for a second time in full-electric mode, which is normally reserved for leaving the No. 7's pit box. Kobayashi also, according to Vasselon, left the third time in full-electric mode.
In its standard pit-launch mode, the Toyotas pull away using electric power and eventually trigger the 2.4-liter twin-turbo V6 internal combustion engine to spark to life farther down pit lane; this method saves fuel.
The three harsh engine triggerings in such a short time span is what led to the clutch failure, according to Vasselon, but what hasn't been explained is why Kobayashi failed to switch from the electric-to-V6 start procedure to the full-V6 start that he was supposed to do upon receiving approval to leave the end of pit lane and fall in behind the safety car.
The No. 7 driver was shown sitting on pit lane, waiting for the safety car with nothing else to do, and had ample time to switch starting procedures. The same was true while waiting for the safety car before his third and final start-up procedure.
Capillaire was at fault for giving Kobayashi a false impression that a track marshal approved his return to the track, which led the No. 7 to start one more time than was necessary.