William D. Perry

Development of piston temperature telemetry system

Abstract The measurement of piston temperature in a reciprocating engine has historically been a very time-consuming and expensive process. Several conditions exist in an engine against which measurement equipment must be protected. Acceleration forces near 2000 Gs occur at Top Dead Center (TDC) in automotive engines at rated speed. Operating temperatures inside the crankcase can range to near 150°C. To allow complete mapping of piston temperature, several measuring locations are required in the piston and data must be obtained under various engine operating conditions. Southwest Research Institute (SwRI) has developed a telemetry-based system that with stands the harsh environments mentioned above. The device is attached to the underside of a piston and temperature data is transmitted to a receiving antenna in the engine crankcase. The key element of this device is a tiny power generator which utilizes the reciprocating motion of the piston to generate electricity, thus allowing the transmitter to be self-powered. Thick-film hybrid circuit construction techniques have been used to keep the package size small. This paper covers the development of the power generator, multiplexer and transmitter circuits, and the receiver system. Sample data is included from two automotive engines.

An Airborne Balloon Launch System (ABLS): Heritage, Concepts and Applications

[Abstract] An air launch balloon system provides an opportunity for observations on a global basis with greatest immediacy. Operating altitudes of 60,000 – 70,000 ft allow the ALBS to take advantage of the relatively low wind speeds in this layer of the atmosphere. When prevailing winds move the asset out of the theatre of operations, a new balloon asset can be launched to maintain coverage. In order to provide complete global coverage, an ABLS can be launched from areas where a ground launch is not possible. If an urgent need for a balloon system in a certain area is identified, an ABLS can be deployed to launch in hours. The ABLS provides total flexibility in selecting the time and place where a balloon system is deployed in support of operational areas. The Offboard Balloon Jammer System (OBJS) was developed by SwRI for the Joint Electronic Warfare Center (JEWC) of Kelly Air Force Base. The requirements for the OBJS called for a 150-lb electronics payload to float at 27,000 ft. for six hours after an airborne launch. The OBJS was integrated and complete testing of the system was performed at SwRI. A very successful free-flight airborne and inflation test of the OBJS system was conducted from Holloman AFB, New Mexico in October of 1993. Since that time, additional work has been conducted in support of planetary ballooning technology development. Descriptions of prior studies, development efforts, potential applications, testing and the current state of the art will be presented.