This invention relates to a device for sensing the engine oil level in a motor vehicle, more particularly, though not exclusively, a motor vehicle, such as, a motorcycle or motorcycle type motor vehicle, when such oil reaches a predetermined level.
Engine oil is required for lubrication of the moving parts inside an internal combustion engine. Insufficient engine oil will increase friction between the moving parts of the engine leading to increased losses and thus low efficiency. Insufficient engine oil can also lead to engine seizure which is dangerous for the rider. A low cost device for checking if the engine oil level has decreased below a predetermined low level will be useful to warn the rider about the state of the engine oil level and take remedial measures. The object of this invention is to propose such device.
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This invention will now be described with reference to
the accompanying drawings which illustrate, by way of
example, and not by way of limitation, one of possible
embodiments of the device proposed herein.
Fig. 1 illustrating the embodiment with the reed switch
open
Fig.2 illustrating the embodiment with the reed switch
closed.
And Fig. 3 illustrating the general assembly of the
embodiment.
The embodiment consists of a permanent magnet M housed within a hollow cylindrical float F. A cylindrical stem S is located at the centre of the float, the said stem
having a reed switch R within it. The stem and the float are housed within a protective housing H such that the float can move along the stem without making contact with the walls of the housing. The float is spaced from the stem which prevents the float from making contact with the stem.. The movement of the float is limited by

the ends of the housing Tl and T2 (top end and bottom end). The housing has slots to allow the engine oil to flow into it when the device is mounted on the crankcase of the vehicle. Electric wiring W passing through the stem is connected to a sensor (such as a lamp L) and battery B to.sense the state of the reed switch R . An 0-Ring is provided at the mounting surface of the device to prevent the engine oil from leaking outside the crankcase.
The device is mounted on the crankcase of the vehicle such that the stem S is perpendicular to the bottom of the crankcase. When oil is filled into the crankcase, the float moves up along with the oil. The upward movement of the float is limited by the top end of the stem. The engine oil level decreases due to continuous operation of the engine.
As long as the float is above the reed switch, that is, the oil level is above the reed switch, the said switch will be

in one state, that is, either in the closed state or in the open state depending on the reed switch construction. When the oil level decreases below the top end of the stem, the float moves downward along with the oil level and when the float reaches the reed switch height, due to the permanent magnet-inside the float, the reed switch is activated to change its state This change in the state of the switch will indicate and warn the user about the oil level, by a sensor, say, by the lamp L going ON or OFF depending upon the state of the switch. The lamp is connected to the switch through wiring W and a battery B. The downward movement of the float is limited by the bottom end of the stem.
The components of the device which are exposed to considerable heat and cold will, preferably, be made of a material, such as, plastic, that can withstand high temperatures up to 180 degree centigrade and low temperatures up to minus 10 degree centigrade.

Where the motor vehicle happens to be a motorcycle, the device is mounted in the crankcase between the gear shaft mounting hole and the kicker shaft mounting hole below the clutch shaft mounting hole. This is to ensure that the magneto cover need not be removed to replace the device. It is only the engine sprocket cover that has to be removed to result in easier servicing of the said device.
The components of the device proposed herein can have a shape and configuration not restricted to those described herein. The housing is provided to reduce the effect of vibrations on the float and reed switch. In the absence of the housing, due to engine vibrations, the engine oil might splash against the float and reed switch thereby leading to erratic oil level indication. With the housing, the engine oil can only enter through the slots at the top and bottom ends thus preventing sudden change in float height. The location of the device is chosen such that it does not foul with other engine

We Claim:
1. A device for sensing the engine oil level in a motor vehicle comprising a permanent magnet housed within a float; a stem encircled by the float, said stem having a reed switch within it; a protective housing for the stem and float such that the float can move along the stem without making contact with the walls of the housing, the stem being spaced from the float for preventing the float from making contact with the stem, the movement of the float being limited by the top and bottom ends of the housing; slots provided for the housing to allow the engine oil to flow into it when the said device is mounted on the crankcase of the vehicle; a sensor electrically connected to the reed switch and to a battery to sense the state of the said switch,

2. A device as claimed in Claim 1 wherein an 0-Ring
is provided to prevent the engine oil from leaking
out of the crankcase.
3. A device for sensing the engine oil level of a motor
vehicle substantially as herein described with
reference to, and as illustrated in, the
accompanying drawings.

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