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Advances in motorized vehicle vibration control have increased consumer expectations to feel minimal vibration when operating vehicles in any environment; on and off road. Small outboard marine engines have a heightened need for vibration isolation, since the user often steers using a tiller arm connected to the outboard. Traditional engine mount systems allow the mount reaction loads to create a periodic torque about the steering axis and result in significant tiller arm shaking forces. This paper presents a novel mount arrangement that minimizes the shaking couple about the steering axis and isolates the tiller from engine vibration. The concept was first modeled using rigid body dynamics software to predict vibration of the tiller arm. Testing confirmed the simulation, and demonstrated a significant reduction of vibration transmitted to the tiller arm and boat seat compared with a traditional focused mount system.

Positive displacement flowmeters can be used to simply and accurately calibrate common flow transducers such as axial turbine and target flowmeters. Two means of utilizing positive displacement devices were studied for use as a laboratory flowmeter calibration. The first method employed a fixed displacement axial piston motor. This proved unsatisfactory due to the difficulty in quantifying flow losses. The second method used a large hydraulic cylinder. An optical encoder measured the position of the cylinder rod, permitting a direct calculation of the flow through the in-line flowmeter being calibrated. Because cylinder leakage is virtually zero at low pressure, flow can be readily calculated knowing the effective cylinder diameter and piston velocity. The method described in this paper permits flow rates to be measured with an accuracy of ±0.1% of the volumetric flow rate. This paper discusses details of the design of the flowmeter and calibration method.