No / Measuring piston crown temperature and pressure during engine development cycle is paramount. This paper presents a new development in short distance telemetry system which includes an on board power generation device. A mechatronic data acquisition system is developed whereby signal conditioning is performed by a module inside the piston and the signal passed to a Bluetooth transmitter module for wireless telemetry to a Bluetooth receiver located in very close proximity, connected to an external host PC. The Data Acquisition Bluetooth module integrates a microcontroller that reads the conditioned sensor signal and performs any other required functionality. The microcontroller firmware includes a server that collates the data and transmits them via Bluetooth to the host PC to display via a client interface. An independent power supply consisting of a rotor incorporating NdFeB magnets and a wire wound stator. As the crankshaft rotates the rotor induces an AC voltage into the stator. A rectifying circuit converts the AC voltage into a regulated DC output voltage that drives the signal conditioning and embedded Bluetooth circuits.

Piston telemetry research involves monitoring the temperatures at specific internal location points within a combustion engine piston. The temperatures are detected with type K thermocouples as voltages and processed to convert them into temperatures using cold junction compensation methods. The present system uses a specific sensor designed to operate in the high temperature environment within the piston, reading multiple thermocouples. Because of the reciprocating motion of the piston, power generation is intermittent and available only when the piston reaches near bottom dead centre, using inductive coupling to power the sensors and transmit data to an evaluation unit for data processing. The planned system involves designing and building a prototype telemetry unit using ¿off the shelf¿ components that integrate the reading of thermocouple outputs, signal processing and cold junction compensation. Wireless telemetry is adopted for data transmission with an integrated Bluetooth and microcontroller module. The data acquisition module can be adapted for other sensors by adapting the firmware uploaded to the microcontroller. The hardware electronics are envisaged to be encased in thermal insulation to enable operation in high temperature environments. The considered system requires a power supply for the integrated components in the form of a power generator and that it should meet two criteria: to be located within confined spaces and to be permanently available, without having to dismantle systems to change batteries. The selected method is an induction generator constructed from a coil stator connected to the piston connection rod big end and a permanent magnet rotor connected to the crankshaft. The suggested mechatronic system is validated against the present system by comparing both systems to determine whether wireless telemetry can perform within acceptable tolerances and limits for the specified task. Then, for acceptable performances, reduce costs and include flexibility to operate in multiple environments. Bench testing shows that the power generator is capable of driving the sensors and the Bluetooth integrated DAQ system. / EPSRC and University of Bradford