Special Characteristics of the HVU 5 Engine Test Bed

An engine test is pointless if the measured values are falsified because the engine test bed changes the properties of the engine to be tested. This is what happens when braking dynamometers of usual design are
used for measuring the specific fuel consumption und the exhaust gas composition of engines like chain saws, because these braking dynamometers have a much higher inertia than a saw chain and thus have similar effects
like an additional flywheel: Changes of speed are slowed down, and the rotation of the engine becomes less uneven. Both deviations from practical operation influence the exhaust gas composition, the last-mentioned
deviation also influences power and the fuel consumption.

The low inertia hydrostatic engine test bed HVU 5 has been developed by Weinlich especially for the simulation of the practical operation of chain saws and similar power tools with light high-speed combustion engines in
order to carry out fuel consumption and exhaust gas tests.

The holding device which supports the chain saws as in practical operation is mounted on a so-called module plate which can be fixed quickly on the table of the test bed without having to be aligned.

The engine test bed’s control unit (shown at the right back of the picture) which is based on the MP Computer proven in engine testing for many years, can be operated after only short training.

For gravimetric fuel consumption metering the balance holding the fuel tank for the engine (shown on the left) transmits its data to the MP Computer which automatically calculates and displays the specific fuel consumption.

For display, memorization, and printing of the measured values the MP Computer can be connected to the serial port of a standard PC shown in front of the MP Computer. The easy-to-handle PC programme „Diagram for Windows“ displays and prints the curves of speed, torque, decreasing weight of the fuel tank, power, counted work, and other values, if measured.

Test reports showing for example maximum power and fuel consumption at certain speeds can be printed directly by the MP Computer while the measurement is done.

Due to its high measuring sensitivity concerning torque the engine test bed HVU 5 is suitable for high-quality tests as requested for example during the development of small high-speed piston engines.
The measuring accuracy can be checked and readjusted anytime with the calibration lever supplied together with the engine test bed.