Rion VM-230 and VM-240A Acoustical Capacity Meter

Rion VM-230 and VM-240A Acoustical Capacity Meter

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The revolutionary Rion Acoustical Capacity and Volume Meters enable the rapid and accurate measurement of irregular shapes without the use of liquids. The Rion Acoustical Capacity and Volume Meters allow accurate measurement of enclosed capacity of a chamber (to within ±0.05 cm3)*1 or the volume of an enclosed object (to within ±0.1 cm3)*2. Each measurement can be made in around 2 seconds.

Although it has many other potential uses, the Acoustical Capacity Meter was primarily developed to measure the capacity of engine combustion chambers either on the head assembly itself (using the VM-240A) or on a complete engine via the spark-plug fitting (VM-230A). These measurements allow the engineer to quickly determine that the compression ratio of each cylinder is correct in far less time than it would normally take, using the traditional oil-filling (Biuret) method.

Power and efficiency are the key reasons for closely monitoring compression ratios. If the compression ratio is too high the fuel-air mixture will self combust before the compression stroke is completed, causing inefficiency, reduced power and potential damage to the engine. Compression which is below the optimum will lead to lower energy being produced by the blast and consequently lower power and efficiency.

Because of the small margin of error between a compression ratio that is too high and one that is too low, sample production engines need to be tested during the manufacturing process. Using the traditional Biuret method only a small number of engines can be tested because testing each cylinder can take around 30 minutes and requires a high level of skill. Because the Rion VM-230A/VM-240A Acoustical Capacity Meter only takes around 2 seconds per cylinder, more measurements can be taken and production quality can be monitored more closely and effectively.

Notes:
*1 when a cylinder head with a volume of 50 cm3 is measured under standard environmental conditions (20°c, 50 %)
*2 when a volume of 100 cm3 is measured under standard environmental conditions (20°c, 50 %)