Continuous on-board diagnostic lubricant monitoring system and method

• US 6,644,095 B2
• Filed: 06/17/2002
• Issued: 11/11/2003
• Est. Priority Date: 10/12/2000
• Status: Expired due to Fees

• Current Assignee: The Lubrizol Corporation (Berkshire Hathaway Incorporated)
• Original Assignee: The Lubrizol Corporation (Berkshire Hathaway Incorporated)
• Inventors: Dayal, Bhupinder Singh, Van Mullekom, Jennifer H., Melnyk, Michael Charles
• Primary Examiner(s): Kwok, Helen
• Assistant Examiner(s): GARBER, CHARLES D
• Application Number:
  US10/173,269
• Publication Number:
  US 20020178780A1
• Time in Patent Office: 512 Days
• Field of Search: 73/530.5, 73/540.1, 73/540.2, 73/10, 73/542.8, 73/542.9, 73/543.1, 73/543.2, 73/543.3, 73/543.4, 73/543.5
• US Class Current: 73/10
• CPC Class Codes: F01M 11/04 Filling or draining lubricant of or from machines or engines
• CPC Class Codes: F01M 11/06 Means for keeping lubricant level constant or for accommodating movement or position of machines or engines
• CPC Class Codes: F01M 11/10 Indicating devices; Other safety devices
• CPC Class Codes: F01M 2011/0475 with combustion of used lubricant in the engine
• CPC Class Codes: F16N 2250/08 Temperature

Abstract

A continuous on-board diagnostic lubricant monitoring system and method evaluates lubricant quality and detects incipient lubricant failure due to contamination by measuring physical characteristics of the lubricant itself. The lubrication system (1) employs a diagnostic cell (27) which samples engine lubricant (EL) from an engine (2), and exposes the samples to sensors (28) which measure its physical characteristics. The senors (28) preferably include a permittivity sensor, a viscosity sensor, and a temperature sensor. Diagnostic testing based on the measurements can be carried out on-board via a controller (30) running selected algorithms or processes. A time to condemning limit for the lubricant, i.e., the time until the lubricant has degraded to given quality level, is calculated based on permittivity data received by the controller (30) from the sensors (28). Likewise, a time to condemning limit is calculated based on viscosity data. Based on the permittivity and temperature data, the controller (30) is able to detect incipient failure of the lubricant due to water or coolant contamination. Additionally, based on the monitored lubricant viscosity, the controller (30) is able to detect fuel contamination. In this manner, a superior lubricant monitoring system and method is achieved which is particularly applicable to railroad locomotives, mining machinery, and other off-highway vehicles.

Claims

1. A method of monitoring a lubricant, said method comprising the steps of:

(a) obtaining measurements of the lubricant'"'"'s viscosity;

(b) obtaining measurements of the lubricant'"'"'s temperature;

(c) normalizing the viscosity measurements based on the temperature measurements such that the normalized viscosity measurements all relate to a common reference temperature; and

,

(d) diagnosing a condition of fuel contamination of the lubricant based on the normalized viscosity measurements; and

(e) distinguishing between different degrees of fuel contamination based on the normalized viscosity measurements.

2. The method according to claim 1 said method further comprising:

(f) determining, based on the normalized viscosity measurements, a time to condemning limit for the lubricant due to fuel contamination.

3. The method according to claim 2 said method further comprising:

(g) determining, based on the normalized viscosity measurements, a time to condemning limit for the lubricant due to quality degradation.

4. The method according to claim 1, said method further comprising:

(e) determining, based on the normalized viscosity measurements, a time to condemning limit for the lubricant.

5. The method according to claim 4, wherein the time to condemning limit is selected from the group consisting of:

an upper viscosity limit under which it is desired that the lubricant'"'"'s viscosity remain, and a lower viscosity limit over which it is desired that the lubricant'"'"'s viscosity remain.

6. The lubrication system for an engine said lubrication system comprising:

a lubricant;

a diagnostic cell which samples the lubricant for diagnostic testing thereof, said cell including;

a viscosity sensor which monitors the lubricant'"'"'s viscosity;

a temperature sensor which monitors the lubricants temperature; and

,

a controller which interfaces with the diagnostic cell to carry out the diagnostic testing, said controller receiving viscosity data from the viscosity sensor and temperature data from the temperature sensor, wherein the viscosity and temperature data is processed to diagnose a condition of the lubricant, and wherein the viscosity data and the temperature data are processed to determine a time to condemning limit for the lubricant.