BASF Octane Rating Engine


The engine is made by the BASF (Badische Anilin- und Soda Fabrik) in 1964 and on him performable to the octane number measurement of the gasolines according to a standard necessary examinations. We compare the knock intensity of the petrol to be examined at constant compression ratio with the similar value of two pieces of reference fuels, beside different air-ratios.

The equipment consists of two capital parts: the internal combustion engine and the electric unit which consist of the retarding synchronous engine and the measurement unit electronics equipments.

Single standing, single-cylinder four-stroke, water-cooled Otto Engine with 332 cm3 piston displacements is the engine. For the reproducible of the measurements the engine must be operated on a constant temperature, which is ensured by a cooling unit consist of two parts: the primer circle is filled with distilled water the medium is boiling in the course of the normal operation, the secondary side of the heat exchanger is joined onto the water system.

The electric motor is used for Otto Engine's launch, the function restrains it on his row then, keeps the rev on the rev requested by the measurement procedure. The two units are with a fan belt in a compulsion contact through the flywheel of the petrol engine.

To the transaction of the octane number measurement we have to keep certain function parameters on particular values, Otto Engine's special parts help in these.

First and most important from among these, that let us be allowed to change the compression ratio in the course of the measurement. The special forming of the unit including the cylinder and a cylinder head is necessary to this in order for us to be allowed to change the compression volume beside the constant stroke of the piston. On the exterior surface of the cylinder being mover procession is connected with a snail, in this manner we can lift or raise the cylinder moving on the forced path turning the snail by a hand twins. Through all these the compression ratio (ε) can be optionally chosen between values of 4-11 and the set value is displayed on an indicator disc found on the side of the engine.




The integral part of the engine is a special mix derivational suffix unit. This consists of three combustible containers, these contains the petrol to be measured and the reference fuels with lower and higher octane number than the petrol. The air ratio can be changed by this on a specific manner. The fuels come from the containers into a swimmer house through a bore. It is possible to set a constant liquid level because the swimmer close the bore, and the current level is traceable on a mm arrengement scale on the side of the swimmer house. The engine sucks in a constant volume of air beside all these, the mix comes into existence in a pulveriser. The fuel which the engine being operated can be changed by a three-way valve. Reasonable, that higher liquid level in the swimmer house effects a higher hydrostatics pressure awakes at the jet, and the emergent fuel-air mix will be richer. Though this true reversely, a lower liquid level yields a poorer mix.

We have to be kept on a defined value of the temperature of the intake air. Onto this aim the mix derivational suffix unit serves, where the air is heated by an electric heater switched by a thermostat to keep the required temperature on a value of 52 °C .

To the examination of the knocking  combustion an electronis knockmetring instrument is needed. The instrument consists of a magnetostrictive pick-up mounted on the head of the testing engine, the amplifier and the knockmetring unit. The magnetostrictive pick-up is actually an inductive transmitter connected to a membrane. The function of the inductive signaller is based on the the law of magnetoelasticity. A magnetized iron rod modifies his magnetic permeability due to the pressure thus  the value of the magnetic flux. In the coil around the rod a current proportional to the flux is generated. Because the fluctuation of the flux is proportional to the temporal change of the pressure reigning in the cylinder space, the signal is equal to the knock intensity.

The components originating from the normal combustion are detached from the signal by  the electronics. The typical signal of the knocking goes thru an amplifier and rectifier in the second stage and displayed on a scale without a dimension running from 0 to 100 as knock intensity.

The octane number of the examined petrol is determianted from the the received values of the references with known octane number  by lineal interpolation.




As the result of the labouratory developments in idicational system is built up on the equipment. In this manner feasible is in the course of Otto Engine's operating the uptake of the indicator diagrams, and different knocking define numbers can be determined and compared by a software.

We supplied the engine in the course of additional developments with exhaust-gas sampling holes, in this manner the NOx, CO, CO2 and THC emission depending  on the air ratio of the different fuels is easily measurable.