5-5 OIL SENSOR (OPTION)
-
5-5-1 DESCRIPTION
0The oil sensor mainly functions to detect position
of thesurface of engineoilinthecrankcase of engines for generaluse and tostoptheengine automatically when the oil level goes downbelow
the lower limit specified.
This prevents seizureof engine from occurring due to insufficient amount of oil in the crankcase.
0Since the sensor has been designed to consume a part of power supplied to the igniter to energize its electronic circuit, any other external power supply is not necessary so thatit can be mountedat the oil filler port.
Introduction of newly developed sensing principle featuressuperdurability and no changewiththe passage of time as itdoes not use any moving part.
I
II
!i
II
i
i
1i
\
oil sensor
Fig.
Merits due to introductionof electrical conductivity detectionare asfollows;
0It hasresistancetomechanicalshocks and property of no changewiththepassage of time as sensing element consists simplyof electrodes having no moving parts.
@At the same time, it is capable of detecting the oil level stably as it is not influenced by engine
-vibrations.
@No error occurs due tofoam and flow of the oil.
@Influence against the ignition system or the electronic units can be neglected because an electric current supplied to the sensor canbe decreased.
There is a great differencebetween electric resistanceof air and that of oil.
Since the resistance of air is far higher than that of oil, more electric current passes through the oil than through the air, although absolute valueof the current is very smalI.
The sensor detects this current differenceand make use of it.
The sensor judges the oil quantity,by comparing a current flowing across a pairof electrodes (inner and outer)withthereference, in sucha way that if a currentflowsbetweentheelectrodesmore than the reference, sufficient oil is in the crankcase, on the other hand, if a current flows less than the reference, oil is not sufficient.
Sinceanelectriccurrentisflowntodetectoilquantity,thisis calledthe“electricalconductivity detection” typeof sensor.
The oil level to be detected is determined by the length of electrodes and their mounting positions with the engine.
”[Power supply]
The sensor makes use of a part of primary power source for ignition of the engine (igniter) to drive the sensor circuit. Powerto the sensorcan usually be derived from the ”stop button”by branching wires out.
-12 -