Spark Plug Velocimeter
What the SPV does:The Spark Plug Velocimeter (SPV) allows measurements of the movement of gas particles in the combustion room of an engine during all cycles (2, 4 strokes or rotational) and often used in the context of "particle image velocimetry (PIV)":
The collected data and the visualisation allows engine manufacturers to improve all design aspects of the engine from increasing power to reduced fuel consumption and cleaner emissions. |
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How the SPV works:The SPV is a robust unit fitting into an engines spark plug socket. It is connected via its data collection unit to a PC allowing the visualisation of the collected data in standard and customised formats. The SPV may be used in dry runs and under normal testing conditions with the engine firing all cylinders. In this case the engine head needs to provide 2 spark plug sockets on all cylinders undergoing testing. For "hot" running, the outer jacket would be (water) cooled.
The SPV can be customised for use in any similar sized sockets. |
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Details & Functions of the SPV:The SPV is a magnifying Laser Doppler Velocimeter. The focal range is adjustable to the required proportions of the combustion chamber and characteristics of the shape of the cylinder and the movement.
The velocimeter moves within the outer sleeve. The measurement point is typically variable from 50mm to 0mm from the glass window allowing the user to probe the compression volume.
The velocimeter can be rotated within the outer sleeve, allowing flow direction to be matched with the 2D X-Y measurement planes.
The silicon glass window is rated for high temperatures, and typical velocity ranges are +-150 metres/second in both axis, with directional sensing.
The typical data output shows:
An entire sequence during the engines movement can therefore be visualised in a slowed down time line showing the movement and directions of the particles from the intake, through to compression, firing and explosion and release of the gas. This may be visualised in a range of statistical and graphical representations allowing overlay of graphics and comparison of tables from different scenarios. The technology has been widely used for many years. The new laser technology introduced by Exact Group makes the application of the SPV sensor quicker and more cost effective. EGs SPV does not to be refocused for different depth and there is no need to remove the SPV from the engine to change it's depth settings. Laser and sensor are enclosed in the SPV and the measurements are directly transferred to the data collector allowing for instant visualisation of the data.
In detail: For further details contact Laser Dynamics. |
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