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A telemetry linkage system has been developed for piston temperature measurements in a direct-injection diesel engine. In parallel with the development of the telemetry linkage system, fast response thermocouples were installed at three piston locations - two on the bowl surface and one on the crown surface. A novel design was used to achieve electrical continuity between the piston and the connecting rod by means of a flexible steel strap pivoted on the piston skirt. The telemetry linkage system was then used to transport the electrical wires from the thermocouples to the external data acquisition system. A series of tests was run to determine the effects of location and load on piston surface temperatures. Surface temperature profiles varied substantially among the three locations, reflecting the differences in the combustion and heat flow characteristics of their surrounding regions.

Historically, driveshaft torque data has been obtained using slip rings. Slip rings, however, are expensive, and require time-intensive driveshaft modifications for proper installation. In addition, the time and expense involved in field servicing units is prohibitive. For these reasons, AISIN Technical Center of America (ATCA) investigated a viable telemetry solution. At the onset of this development activity, existing torque telemetry solutions had their own issues. In particular, they did not offer the same data resolution as slip rings, they lacked sufficient battery life for long-term, real-world testing applications, and they suffered from data drop-outs. ATCA worked with TECAT Performance Systems to develop a torque telemetry solution that addressed all of these issues. This paper presents the development activity involved, alongside real-world measurement data showing the results of both the slip ring and telemetry solutions.