Capacitive oil level sensor for vehicular drive axles

A capacitive oil level and temperature sensor mounted to a drive axle housing of a motor vehicle, said drive axle housing having an oil reservoir containing a certain amount of lubricating oil, said capacitive oil level sensor provided to measure an oil level in said reservoir, said sensor comprising:

• an L-shaped housing having a first leg at least partially immersed in said oil reservoir and a second leg disposed substantially perpendicular from said first leg and extending outside said drive axle housing substantially horizontally;
• an L-shaped flat printed circuit board having a first leg disposed in said first leg of said sensor housing and a second leg disposed in said second leg of said sensor housing;
• at least one first electrode plate fixed inside said first leg of said sensor housing;
• at least one second electrode plate attached to said first leg of said printed circuit board opposite to said first electrode plate, wherein said first and second electrode plates forming a capacitor, a capacitance of said capacitor is a function of said level of said oil in which said capacitor is immersed;
• a threaded mounting surface provided at said second leg of said sensor housing and suitable for threading said sensor into a threaded fill plughole in said drive axle housing;
• a wrench engaging surface secured to said second leg of said sensor housing and adapted for mounting said sensor to said drive axle housing;
• a thermistor for measuring an oil temperature in said oil reservoir, said thermistor mounted to said printed circuit board;
• and
• an electronic sensor circuitry electrically coupled to said oil level detecting capacitor and said thermistor, and adapted to generate an electric signal proportional to said oil level in said drive axle housing and an electric signal proportional to said oil temperature in said oil reservoir, wherein said electronic sensor circuitry is supported on said second leg of said printed circuit board.

A drive axle housing of a motor vehicle, said axle housing comprising:

• an enlarged central portion housing a differential assembly, said central portion forming an oil reservoir containing a certain amount of lubricating oil;
• a pair of opposite axle tubes extending from said central portion;
• and
• a capacitive oil level sensor mounted to said central portion of said drive axle housing and provided for measuring an oil level in said oil reservoir, wherein said capacitive oil level sensor includes a housing having a first leg at least partially immersed in said oil reservoir and a second leg extending from said first leg at an angle thereto, said first leg houses an oil level detecting capacitor at least partially is immersed in said oil reservoir to detect said oil level.