5-5 OIL SENSOR
5-5-1 DESCRIPTION
0 The oil sensormainlyfunctions to detect
position of thesurface of engine oil in the crankcase of engines for general use and to stop the engine automatically when the oil level goes down below the lower limit specified.
Thispreventsseizure of enginefromoccurring
duetoinsufficientamountof oil in the crankcase.
0Since the sensor has been designed to consume
part of power supp1ie.d to theigniter to energizeitselectronicscircuit,anyother
external power supply is not necessary so that it
can be mounted at the oil filler port. | I | OIL SENSOR | |
Introduction of newlydevelopedsensing | no | Fig. | |
principlefeaturessuperdurabilityand | |||
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change with the passageof time as it does not use any moving part.
:zMerits due to introduction of electrical conductivity detection are as follows;
It hasresistancetomechanicalshocksandproperty of nochangewiththepassage of timeas sensing element consists simplyof electrodes having no moving parts.
&A Atthesametime,itiscapable of detectingthe oillevelstablyasitisnotinfluenced by engine vibrations.
:zNo error occurs due to foam and flow of the oil.
&n Influence against the ignition system or the electronics units can be neglected because an electric current supplied to the sensor can be decreased.
5-5-2 PRINCIPLE OF SENSINGOILLEVEL
There is a great difference between electric resistanceof air and that of oil.
Since the re.sistance of air is far higher than that of oil, more electric current passes through the oil than through the air, although absolute value of the current is very small.
The sensor detects this current difference and makeuse of it.
The sensor judges the oil quantity, by comparing a current flowing across a pair of electrodes (inner and outer)withthereference, in suchawaythat if acurrent flows betweentheelectrodesmorethanthe reference, sufficient oil is in the crankcase, on the other hand, if a current flows less than the reference, oil is not sufficient.
Sinceanelectriccurrent isflown to detectoilquantity,thisiscalledthe"electricalconductivity detection" type of sensor.
The oil level to be detected is determined by the length of electrodes and their mounting positions with the engine.
5-5-3 HOW ITOPERATES
[Power supply]
The sensor makes use of a part of primary power source for ignition of the engine (igniter) to drive the sensor circuit. Power to the sensor can usually be derived from the "stop button"by branching wires out.
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