If 24 hours of hard racing and winning endurance racing events like 24 Heures du Mans are your goal, what are some of the considerations that go into your electronics system?
While at Jota Sport during HPAs recent Goodwood trip the team gave us the chance to have a look over their 234MPH (376kmh) Oreca 07 LMP2 cars electronic package. Until 2020 LMP2 class cars must run a 600HP (approx) Gibson Motorsports naturally-aspirated 4.2 litre (260 in3) GK428 V8 petrol engine, and to fit class rules this Jota Sports Oreca is no exception.
The V8 is controlled by a Cosworth MQ12 ECU which is the same ECU you will find in other forms of professional motorsports past and present such as MotoGP, Formula Nippon (Super Formula) and Formula Two. The MQ12 can control an engine that revs out to 22,000 RPM and with twenty configurable injector/PWM drivers combined with twelve IGBT ignition outputs and sixteen logic level coil driving outputs, the ECU capable of fully sequential fuelling on normally aspirated, turbo and supercharged engines including V12 and W16s. In a nutshell for an ECU at this level, it is probably easier to list the few things it can’t do.
In the case of Jota Sports Oreca LMP2, the Cosworth MQ12 controls all of the things you would expect such as fuel and ignition through to traction control, closed-loop fuel control, performance-based knock control and of course the pit speed limiter and full course yellow limiter. Another interesting feature the MQ12 can control is variable geometry intake or exhaust systems which have been used and experimented with in F1 and MotoGP over the years.
The ECU is paired with a Cosworth IPS32 PDM and a CAN keypad which removes the need for fuses and relays adding an extra level of reliability and durability while maintaining a compact and simple loom due to the requirement of only 4 wires to operate over a CAN Bus network, which includes the requirement for a power and earth.
The pneumatically controlled Xtrac gearbox does use a separate computer to control the air compressor and Andre gives us a great rundown on how this is done. Electronic power steering control is also utilized not just for track setup but also for driver preference so that during 24-hour races it is as easy as possible for multiple drivers to share the same car but use their own individual preferences to get the most from it as fast as possible.
All of these components also have a lifespan of use at this level, and while that may seem like an unnecessary expense to some of us for such top quality units to only be deemed reliability for a certain amount of racing hours, in reality for teams at this level the cost of not finishing a race due to an avoidable electrical issue in the 23rd hour etc would be more devastating and costly in the long term than taking such precautions.
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