Uses Of Flow Meter In Engine Oil Flow Measurement

By Author: Rahul Sharma
Total Articles: 12
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One of the most difficult flow measurements for the automotive engineer is to measure the engine oil flow rate under operating conditions. With the engine mounted on a test bench and coupled to a dynamometer, the job is slightly easier due to the increased space availability, but none the less, careful selection and installation of the flow measurement system is required. What are the flow meter options? Well, industry standards seem to exist to some extent, but this does not mean they are correct. Let us look at some options.

(1) The positive displacement meter, this could be in the form of a gear meter, piston meter or helical screw to name a few. These meters are generally on the higher cost side and can cause issues when installed due to their relatively high pressure drop. Although quite good at operating across wide viscosities they do suffer from meter slippage at low viscosities. Meters vary in size, but can often be installed without the need for any flow conditioning. Used by some engine test houses but not an ideal solution.

(2) Turbine flow meter, generally one of the most widely used flow meters for ...
... engine oil flow measurement, mainly due to its low costs and small size. They are sensitive to oil and fluid flow profile effects, so it is extremely important to calibrate the flow meter across the varying oil viscosity range and with its installed upstream and downstream flow conditioning tubes. To ensure accurate results when in use, it is essential to match the installed conditions as close as possible.

(3) Coriolis Meters. Very good high accuracy meters, that would only be suited to fixed installations. These meters remain highly expensive and are large in size, compared to the turbine and positive displacement meters. These meters have progressed well over the last 10 years, but can still be prone to poor installation, vibration and zero drift measurement errors. Ideal for test bench use where they are permanently installed, and with straight tube models now becoming a norm, they offer low pressure drop and excellent viscosity range.

Having decided on your method of flow measurement, and undertook the required level of flow meter calibration across the range of operating temperatures, you are close to taking a fundamental step forward in acquiring good flow measurement results. Engineers relatively new to engine lubrication studies should seek advice from the Flow Calibration Laboratory.

Other Issues to bear in mind. The complex nature of engine oil flow measurement means it is very difficult to get accurate oil flow readings from a running engine, but the informed engineer can make sound engineering judgment on their measurement process. Keep in mind the influences of oil viscosity, oil temperature, meter installation effect on flow meter and oil pump performance, oil aeration, relief valve effects and hysteresis, fuel dilution effects, engine oil levels, etc.

Flow Meter as well as data logger instruments must be bought from a trusted and reputed manufacturing company to avoid being duped on the grounds of low durability.