Method and apparatus for measuring the liquid level in tanks subjected to varying accelerations

• US 4,768,377 A
• Filed: 11/13/1986
• Issued: 09/06/1988
• Est. Priority Date: 11/16/1985
• Status: Expired due to Term

• Current Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Original Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Zabel, Wolfgang, Gebhardt, Knut, Habelmann, Erich, Beisenkotter, Horst
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Scanlon, Patrick R.
• Application Number:
  US06/930,442
• Time in Patent Office: 663 Days
• Field of Search: 73/290 R, 73/290 V, 73/304 R, 73/304 C, 73/308, 73/313, 73/317, 364/509, 364/571, 340/618, 340/625, 340/59, 340/526, 340/529, 340/530, 340/442, 340/573, 123/196 S, 123/198 D, 184/6.4, 184/108
• US Class Current: 73/313
• CPC Class Codes: F01M 11/12 concerning lubricant level
• CPC Class Codes: G01F 23/80 Arrangements for signal processing

Abstract

It will thus be seen that the method for measuring the level of a liquid contained in a reservoir which is subjected to varying accelerations is carried out by means of a level sensor which signals when the level of the liquid drops below a predetermined level, and a warning device which is activated if the sensor signal is applied thereto uninterruptedly for a predetermined minimum period of time and results in maximizing functional reliability of the warning signal issuing means during all types of movement situations of the reservoir, while false alarms are virtually eliminated. This is accomlished in that each occurrence involving the uninterrupted application of a sensor signal for a period which is longer than the predetermined time period (t₁) is registered as an event, and in that the warning device is activated after a predetermined number (n) of events have been registered within a predetermined period of time (m). The apparatus used to implement this method is comprised of a reservoir, a level sensor fixedly mounted therein for signaling when the liquid drops below a predetermined minimum level, a warning device which is activated by the level sensor after a sensor signal has been applied thereto uninterruptedly for a predetermined minimum period of time, and a warning signal indicating device as well as an event storage device for storing each activating event and for actuating the warning signal issuing device at the end of a preset event storage phase.

Claims

1. The method of measuring the level of liquid in tanks subject to varying acceleration, comprising the steps of:

generating a sensor signal when the liquid has dropped below a preset minimum level,

detecting each event of a sensor signal being on continuously for a longer time than a first preset minimum period (t₁) in the range of 3 to 16 seconds,

generating a warning signal whenever a preset number (n) of events are detected during another period (m) in the range of 10 to 20 minutes, and

generating the warning signal when the sensor signal is continuously on for a second preset minimum time period (t₂) in the range of 31 to 127 seconds.

2. The method of measuring the level of liquid in tanks subject to varying acceleration, comprising the steps of:

generating a sensor signal when the liquid has dropped below a preset minimum level,

detecting each event of a sensor signal being on continuously for a longer time than a first preset minimum period (t₁),

generating a warning signal whenever a preset number (n) of events are detected during another period (m) which is long in comparison to the first minimum period, and

generating the warning signal when the sensor signal is continuously on for a second preset minimum time period (t₂) which is greater than the first minimum time period (t₁).

3. The method of measuring the level of engine oil in an oil reservoir of a vehicle engine subject to varying acceleration, comprising the steps of:

generating a sensor signal when the oil has dropped below a preset minimum level,

detecting each event of a sensor signal being on continuously for a longer time than a first preset minimum period (t₁),

generating a warning signal whenever a preset number (n) of events are detected during another period (m) which is long in comparison to the first minimum period, and

generating the warning signal when the sensor signal is continuously on for a second preset minimum time period (t₂) which is greater than the first minimum time period (t₁).

4. The method of measuring the level of engine oil in an oil reservoir of a vehicle engine subject to varying acceleration, comprising the steps of:

generating a sensor signal when the oil has dropped below a preset minimum level,

detecting each event of a sensor signal being on continuously for a longer time than a first preset minimum period (t₁),

generating a warning signal whenever a preset number (n) of events are detected during another period (m) which is long in comparison to the first minimum period,

generating the warning signal when the sensor signal is continuously on for a second preset minimum time period (t₂) which is greater than the first minimum time period (t₁), and

repeating the warning signal after the engine is stopped.