BMW 745i software error, desynchronization

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BMW 745isoftware error, desynchronization
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External view
The problem software error, a desynchronization
of the valvetronic motors

• Rough running engine, possibly stall
• Severity 6 incidents in 5,470 cars

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Players

• BMW makes BMW 745
• Bosch makes digital engine management control
  unit

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BMW Cost

• To repair Reprogram ECU
• Recalls not uncommon in industry
• BMW 5,470 cars _at_ 68,500 Rev 372 mil
• Compare Cost Recall BMW X5
• 164,000 units _at_ 66,800 Rev 10 bil.
• 5 Million
• 30 per SUV

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Bosch

• Car components supplier
• Expect to sell 1 million units
• DI-Motronic ECU

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Blame game

• Only contact, Bosch employee
• Mr. Hans BarhoStuttgart, Germany
• 6 reported incidences, 2 rear endings
• alleged injury of BMW passengers
• Fault of drunk or inattentive following drivers

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Source of bug

• Real-time performance

http//www.howstuffworks.com/diesel1.htm
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Controlling valves

• V-valve cutting edge technology
• Engine power
• Fuel Efficiency

???
-- Auto-tech Daily, Feb 5, 2003
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Development

• Why 2 ECU? Maybe, system Complexity
• 16 Sensors control piston
• Adapts to changing driving conditions
• 1k-7k rpm, 140-1000 µs cycle
• Software dev. required to meet schedule
• Matlab modeling and simulation
• ASCET-SD, control systems
• LABCAR
• INCA, calibration tool

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Test environment

• Testing in general
• Simulation vs. real world
• Wide range of parameters depending on environment
• Distributed RT synchronization (speculation)
• Synchronized clocks
• Should share state between ECU
• BMW and Bosch development coordination?

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Economically feasible

• Economical
• Rare 6 of 5470 incidents
• New product user testing
• Cost of recall vs. time to market
• Engineering
• Should have been anticipated!

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Start car

• No key, start with microchip and button

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• MSRP 68,000

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Valvetronic

• http//www.histomobile.com/histomob/tech/2/118.htm

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Complexity of problem

• Real-time _at_ 1k-7k rpm, 140-1000 µs
• 16 Sensors
• Adjusting parameters