Search Results

Waste heat recovery in medium-power systems below 400 kW waste heat power asks for a novel expansion engine concept for water-based Rankine steam cycles. The aim is to combine the advantages of reciprocating piston engines and of turbines at reasonable costs. The so-called rotational wing-piston expander uses two pivoting shafts, each holding two wing-like pistons within one housing, that perform a cyclic movement relative to each other. Thus, four working chambers with varying volumes are shaped, each experiencing repetitive compression and expansion. This solution offers the possibility of sealing the lubricated gearbox against the steam-flooded section containing the working chambers with rotational seals. For the development of the expansion engine, starting with an initial approach for a functional prototype, experimental investigations are carried out. Motored tests are performed in order to scrutinize kinematics and mechanics.

This paper reports on a new generation of silicon gyroscopes, which can be used as angular rate sensors for roll-over sensing or navigation control. The sensor is fabricated in standard Si-surface micromachining technology and encapsulated under vacuum conditions using an Si-micromachined cap wafer. The sensor consists of an electrostatically driven oscillating disk, which reacts with a tilt movement when an angular rate is applied due to the conservation law for angular momentums. The tilt movement is then detected capacitively by electrodes on the substrate underneath the oscillating disk. The sensor is packaged in a standard SMD housing (PLCC44).