Engine oil indicator

• US 4,306,525 A
• Filed: 05/12/1980
• Issued: 12/22/1981
• Est. Priority Date: 05/12/1980
• Status: Expired due to Term

• Current Assignee: General Motors Corporation (General Motors Company)
• Original Assignee: General Motors Corporation (General Motors Company)
• Inventors: Faxvog, Frederick R.
• Primary Examiner(s): Cox, Ronald B.
• Application Number:
  US06/149,288
• Time in Patent Office: 589 Days
• Field of Search: 73/293, 73/DIG. 11, 123/198 D, 123/196 R, 123/196 S
• US Class Current: 123/196.00S
• CPC Class Codes: F01M 11/12 concerning lubricant level
• CPC Class Codes: F01M 2011/14 for indicating the necessity to change the oil
• CPC Class Codes: F02B 1/04 with fuel-air mixture admission into cylinder
• CPC Class Codes: F16N 2200/02 Oxidation
• CPC Class Codes: F16N 2250/08 Temperature
• CPC Class Codes: F16N 2250/34 Transparency; Light; Photo sensor
• CPC Class Codes: F16N 2260/04 Oil level
• CPC Class Codes: F16N 2260/18 necessity of changing oil
• CPC Class Codes: F16N 29/00 Special means in lubricating arrangements or systems providing for the indication or detection of undesired conditions; Use of devices responsive to conditions in lubricating arrangements or systems
• CPC Class Codes: G01F 23/2921 for discrete levels

Abstract

A single optical sensor coupled to an oil return line in an internal combustion engine is coupled to a control circuit for determining during a first time interval when the engine is started whether the crankcase oil level is sufficient and during a second time interval after the engine is running whether the oil needs to be changed.

Claims

1. An engine oil indicator in an internal combustion engine having an oil sump, an oil pump for distributing oil from the sump throughout the engine, and a return line carrying a portion of the pumped oil back to the sump comprising

an optical sensor coupled to the return line at a location below the normal oil level so that when the engine is off the sensor is immersed in oil when the oil level is normal and is above the oil when the oil level is substantially below normal,

the sensor comprising a radiation source spaced from a radiation detector and arranged to pass the radiation through a fixed thickness of oil contained in the return line, the detector having an electrical output signal level varying according to the light transmission from the source to the detector whereby the presence of oil and its opacity can be determined from the signal, and

a circuit responsive to the output signal for sampling the signal during a first time interval approximately when the engine is first started for determining whether the oil level is low and providing an indication thereof and for sampling the signal during a second time interval later than the first time interval for determining whether the oil opacity exceeds a preset limit and providing an indication thereof.

2. An engine oil indicator in an internal combustion engine having an oil sump, an oil pump for distributing oil from the sump throughout the engine, and a return line carrying a portion of the pumped oil back to the sump comprising

an optical sensor coupled to the return line at a location below the normal oil level so that when the engine is off the sensor is immersed in oil when the oil level is normal and is above the oil when the oil level is substantially below normal,

the sensor comprising a radiation source spaced from a radiation detector and arranged to pass the radiation through a fixed thickness of oil contained in the return line, the detector having an electrical output signal level varying according to the light transmission from the source to the detector whereby the presence of oil and its opacity can be determined from the signal, and

a circuit responsive to the output signal for sampling the signal during a first time interval when the engine is first started and including a first comparator for comparing the signal to a first threshold valve to verify the presence of oil for determining whether the oil level is low and providing an indication thereof and for sampling the signal during a second time interval later than the first time interval and including a second comparator for comparing the signal to a second threshold valve for determining whether the oil opacity exceeds a preset limit and providing an indication thereof.

3. An engine oil indicator in an internal combustion engine having an oil sump, an oil pump for distributing oil from the sump throughout the engine, and a return line carrying a portion of the pumped oil back to the sump comprising

an optical sensor coupled to the return line at a location below the normal oil level so that when the engine is off the sensor is immersed in oil when the oil level is normal and is above the oil when the oil level is substantially below normal,

the sensor comprising a pair of spaced windows defining a passage of fixed thickness for carrying the oil flow through the return line, a light emitting diode adjacent one window outside the passage for passing radiation through the passage, and a radiation detector adjacent the other window and exposed to radiation transmitted through the oil, the detector having an electrical output signal level varying according to the light transmission from the source to the detector whereby the presence of oil and its opacity can be determined from the signal, and

a circuit responsive to the output signal for sampling the signal during a first time interval when the engine is first started for determining whether the oil level is low and providing an indication thereof and for sampling the signal during a second time interval later than the first time interval for determining whether the oil opacity exceeds a preset limit and providing an indication thereof.