BLUETOOTH DEVICE SAVES THE DAY
Wireless onboard monitoring provides valuable data that prevents failures saves time saves money saves lives
INTRODUCING THE DAS WITH BLUETOOTH
Simulation device saves engines from catastrophic failure and expensive recalls
Catastrophic engine failure can lead to very expensive recalls. So when a major car manufacturer had a serious problem of connecting rod bolt loosening in one of his top models. Con rod bolt self loosening when undetected, would lead to the serious damage of the con rod (fig) and eventually to the catastrophic damage of the whole engine.
The manufacturer came to MAHLE International GMBH for help.
Preliminary analysis showed that joint failures may be intrinsic to a fastener condition, such as pre-load, thread geometry and/or coating. Or engine parameters such as revolutions per minute (RPM), resonance frequency, and transverse loads exerted on the connecting rod caused by crankpin and/or crank throw bending and crankpin due to cylinder misalignment.
MAHLE initiated a collaborating effort with SensorData Tech of Shelby Twp.
In order to zero-in on the cause of bolt self-loosening in this case, a Data Acquisition System (DAS) manufactured by SensorData, was modified to fit the piston of the case study engine.
The DAS used a Bluetooth transmitter and was used inside the crankcase. The purpose of the test was to measure the magnitude of the bending force acting on the bolt in a typically running engine at peak cylinder pressure.
Test results showed that when engine loading was maintained at 10% (throttle percent opening) while increasing engine speed, bolt bending increased proportionally and was always positive. When engine full load was applied, the bending became reversed and of much greater magnitude.
With probable cause of bolt self-loosening established and possible solutions proposed, therefore, there existed a need to provide a device that simulates the loading conditions that may occur at the crankshaft end of a connecting rod during operation of a reciprocating engine.
This device was a fixture developed by SensorData and tested by MAHLE using force values obtained from the DAS above. The fixture was designed to fit any hydraulic or electro-mechanical load frame.
This mutual effort between MAHLE and SensorData not only solved the problem of a flagship car model, saving a costly recall, but also answerd the need for a device that simulates the loading conditions that may occur at the crankshaft end of a connecting rod during operation of a reciprocating engine.
The device was granted a US 8,276, 464 B2 Patent by the patent office of the US.
This collaborative effort between SensorData and MAHLE was detailed in a SAE paper titled “Dynamic Connecting Rod Bolt Self-Loosening in Internal Combustion Engines” 2010-01
BENEFITS:
• Simulates loading conditions at crankshaft
• Prevents catastrophic engine failure
• Uniique Bluetooth data acquisition system
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