Method of monitoring engine lubricant condition

• US 6,513,368 B2
• Filed: 06/28/2002
• Issued: 02/04/2003
• Est. Priority Date: 02/22/2001
• Status: Expired due to Fees

• Current Assignee: International Truck Intellectual Property Co. LLC (Volkswagen AG)
• Original Assignee: International Truck Intellectual Property Co. LLC (Volkswagen AG)
• Inventors: Calstrom, Kevin R, Larson, Gerald L, Bondarowicz, Frank
• Primary Examiner(s): Williams, Hezron
• Assistant Examiner(s): POLITZER, JAY L
• Application Number:
  US10/184,721
• Publication Number:
  US 20020166366A1
• Time in Patent Office: 221 Days
• Field of Search: 73/530.5, 73/617.6, 73/32.R, 123/376, 123/463, 123/452, 324/672, 324/663, 508/545, 508/294, 701/30
• US Class Current: 73/53.05
• CPC Class Codes: F01M 2011/14 for indicating the necessity to change the oil
• CPC Class Codes: G01N 33/2888 Lubricating oil characteristics, e.g. deterioration lubricating properties G01N33/30

Abstract

A method for generating indicators relating to the condition of lubricating oil in an internal combustion engine. A set of variables relating to operation of the internal combustion engine serve as proxy variables for brake mean effective pressure developed by the internal combustion engine. Operation of an engine is monitored to develop values for the proxy variables. Soot being added to the lubricating oil from the developed values and accumulated to provide an estimate of total soot in the lubricating oil. Lubricating oil temperature is periodically monitored and a history of the lubricating oil temperature measurements is kept to allow generation therefrom of an estimate of shear of the lubricating oil. Accumulated estimate of soot is kept as a distance remaining until the lubricating oil becomes unsuitable for continued use in the internal combustion engine. Similarly, estimated shear is expressed as a distance until the lubricating oil is to be replaced. Additional factors may be monitored and similarly used to determine the distance until an oil change is required, including the dielectric coefficient of the lubricating oil, temperature history of the oil and total cylinder firing events.

Claims

1. An control mechanism for an internal combustion engine providing indication of a need to change lubricating oil in the internal combustion engine, the control mechanism comprising:

a plurality of sensors coupled to the internal combustion engine providing engine data relating to brake mean effective pressure, lubricating oil temperature, engine coolant temperature, dielectric coefficient of the lubricating oil, lubricating oil level, fuel flow, engine rotational speed and firing timing;

a computer connected to receive the engine data and including data storage space to retain accumulated and filtered measurements based on the engine data;

a program stored on the computer embodying a model of lubricating oil condition based on the engine data and the accumulated and filtered measurements based on the engine data; and

said program including steps for;

determining engine load from fuel flow and engine speed;

developing adjustment coefficients based on engine load, temperature and piston timing;

estimating soot being added to the lubricating oil from each cylinder event by multiplying a fuel injection quantity for the cylinder event by the adjustment coefficients;

accumulating an estimate of total soot in the lubricating oil by summing the estimated soot figures for each cylinder event; and

relating the estimate of total soot to a soot oil change interval.

2. The control mechanism of claim 1, wherein the program further comprises modules providing:

a history of the lubricating oil temperature measurements generating therefrom an estimate of oxidation of the lubricating oil obtained from temperature cycles of the lubricating oil; and

relating the history of oil temperature measurements as a proxy for oxidation of the oil to an oxidation oil change interval.

3. The control mechanism of claim 2, wherein the program further comprises modules providing:

a chart of expected lubricating oil dielectric coefficients against lubricating oil temperature.

4. The control mechanism of claim 3, wherein the program further comprises modules:

responsive to operator request to provide the current mileage until an oil change is required and what limiting factor determines the mileage estimate.