APPARATUS AND METHOD FOR DIAGNOSING LUBRICANT DEGRADATION IN INTERNAL COMBUSTION ENGINE

• US 20170198615A1
• Filed: 01/03/2017
• Published: 07/13/2017
• Est. Priority Date: 01/12/2016
• Status: Active Grant

• Current Assignee: Mazda Motor Corporation
• Original Assignee: Mazda Motor Corporation
• Inventors: WADA, Kuniaki, MIYAMOTO, Kouichi, ISHII, Kenya, MIZUBA, Tomonobu, HANDA, Tomohisa, FUJITA, Takayoshi
• Granted Patent: US 10,208,638 B2
• Time in Patent Office: Days
• CPC Class Codes: F01M 11/10 Indicating devices; Other safety devices
• CPC Class Codes: F01M 2011/1466 by considering quantity of soot
• CPC Class Codes: F01M 2250/60 Operating parameters
• CPC Class Codes: F01M 2250/62 Load
• CPC Class Codes: G01N 33/2835 specific substances contained in the oil or fuel
• CPC Class Codes: G01N 33/2888 Lubricating oil characteristics, e.g. deterioration lubricating properties G01N33/30

Abstract

An apparatus for diagnosing lubricant degradation includes a soot amount estimator configured to estimate an amount of soot formed in a predetermined period in a combustion chamber of an engine, and diagnoses the degradation of a lubricant based on a cumulative value of the amount of soot estimated. The soot amount estimator calculates the amount of soot based on a speed of the engine and a load parameter related to a load of the engine, and corrects, based on a temperature parameter correlated to the temperature of the combustion chamber, the amount of soot calculated into an increased value if the temperature parameter is lower than a predetermined first temperature.

Claims

1. A method for diagnosing degradation of a lubricant in an internal combustion engine, the method comprising:

estimating an amount of soot, formed in a predetermined period in a combustion chamber of the internal combustion engine, based on a speed of the internal combustion engine and a load parameter related to torque generated by the internal combustion engine;

correcting the amount of soot estimated into an increased value if a temperature parameter correlated to a temperature of the combustion chamber is lower than a predetermined first temperature;

calculating a cumulative value of the amount of soot estimated; and

determining degradation of the lubricant in the internal combustion engine based on the cumulative value of the amount of soot.

2. The method of claim 1, wherein

if the temperature parameter is equal to or lower than a second temperature that is lower than the first temperature,

estimation is made that the amount of soot decreases as the speed of the internal combustion engine increases in a low engine speed range, and

that the amount of soot increases as the speed of the internal combustion engine increases in a high engine speed range where the speed of the internal combustion engine is higher than in the low engine speed range.

3. The method of claim 2, wherein

if the temperature parameter is higher than the second temperature and lower than the first temperature, the rate of increase in the amount of soot with the increase in the speed of the internal combustion engine is allowed to decrease in the high engine speed range as the temperature parameter increases.

4. The method of claim 2, wherein

the amount of soot is estimated based on the speed of the internal combustion engine, the load parameter, and first temperature data if the temperature parameter is equal to or higher than the first temperature, and is estimated based on the speed of the internal combustion engine, the load parameter, and second temperature data if the temperature parameter is equal to or lower than the second temperature,

the first temperature data representing a relationship among the speed of the internal combustion engine, the load parameter, and the amount of soot when the temperature parameter is the first temperature, and

the second temperature data representing a relationship among the speed of the internal combustion engine, the load parameter, and the amount of soot when the temperature parameter is the second temperature, and

if the temperature parameter is higher than the second temperature and lower than the first temperature, a first temperature soot amount is calculated based on the speed of the internal combustion engine, the load parameter, and the first temperature data, a second temperature soot amount is calculated based on the speed of the internal combustion engine, the load parameter, and the second temperature data, and the amount of soot is estimated by linear interpolation between the first and second temperature soot amounts.

5. The method of claim 3, wherein

the amount of soot is estimated based on the speed of the internal combustion engine, the load parameter, and first temperature data if the temperature parameter is equal to or higher than the first temperature, and is estimated based on the speed of the internal combustion engine, the load parameter, and second temperature data if the temperature parameter is equal to or lower than the second temperature,

the first temperature data representing a relationship among the speed of the internal combustion engine, the load parameter, and the amount of soot when the temperature parameter is the first temperature, and

the second temperature data representing a relationship among the speed of the internal combustion engine, the load parameter, and the amount of soot when the temperature parameter is the second temperature, and

if the temperature parameter is higher than the second temperature and lower than the first temperature, a first temperature soot amount is calculated based on the speed of the internal combustion engine, the load parameter, and the first temperature data, a second temperature soot amount is calculated based on the speed of the internal combustion engine, the load parameter, and the second temperature data, and the amount of soot is estimated by linear interpolation between the first and second temperature soot amounts.

6. An apparatus for diagnosing degradation of a lubricant in an internal combustion engine, the apparatus comprising:

a first sensor configured to detect a speed of the internal combustion engine and output a detection signal;

a second sensor configured to detect a load parameter related to torque generated by the internal combustion engine and output a detection signal;

a third sensor configured to detect a temperature parameter correlated to a temperature of a combustion chamber and output a detection signal;

a soot amount estimator configured to receive the detection signals from the first, second, and third sensors, and calculate an amount of soot formed in a predetermined period in the combustion chamber of the internal combustion engine based on the speed of the internal combustion engine and the load parameter; and

a diagnostic unit configured to diagnose degradation of the lubricant based on a cumulative value of the amount of soot estimated by the soot amount estimator, wherein the soot amount estimator corrects, based on the temperature parameter, the amount of soot calculated into an increased value when determining the temperature parameter to be lower than a predetermined first temperature.

7. The apparatus of claim 6, wherein

when determining the temperature parameter to be equal to or lower than a second temperature that is lower than the first temperature,

the soot amount estimator estimates that the amount of soot decreases as the speed of the internal combustion engine increases in a low engine speed range, and that the amount of soot increases as the speed of the internal combustion engine increases in a high engine speed range where the speed of the internal combustion engine is higher than in the low engine speed range.

8. The apparatus of claim 7, wherein

when determining the temperature parameter to be higher than the second temperature and lower than the first temperature, the soot amount estimator allows the rate of increase in the amount of soot with the increase in the speed of the internal combustion engine to decrease in the high engine speed range as the temperature parameter increases.

9. The apparatus of claim 7, wherein

the soot amount estimator stores

first temperature data representing a relationship among the speed of the internal combustion engine, the load parameter, and the amount of soot when the temperature parameter is the first temperature, and

second temperature data representing a relationship among the speed of the internal combustion engine, the load parameter, and the amount of soot when the temperature parameter is the second temperature, and

the soot amount estimator estimates the amount of soot based on the speed of the internal combustion engine, the load parameter, and the first temperature data when determining the temperature parameter to be equal to or higher than the first temperature, and estimates the amount of soot based on the speed of the internal combustion engine, the load parameter, and the second temperature data when determining the temperature parameter to be equal to or lower than the second temperature, and

when determining the temperature parameter to be higher than the second temperature and lower than the first temperature, the soot amount estimator calculates a first temperature soot amount based on the speed of the internal combustion engine, the load parameter, and the first temperature data, calculates a second temperature soot amount based on the speed of the internal combustion engine, the load parameter, and the second temperature data, and estimates the amount of soot by linear interpolation between the first and second temperature soot amounts.

10. The apparatus of claim 8, wherein

the soot amount estimator stores

first temperature data representing a relationship among the speed of the internal combustion engine, the load parameter, and the amount of soot when the temperature parameter is the first temperature, and

second temperature data representing a relationship among the speed of the internal combustion engine, the load parameter, and the amount of soot when the temperature parameter is the second temperature, and

the soot amount estimator estimates the amount of soot based on the speed of the internal combustion engine, the load parameter, and the first temperature data when determining the temperature parameter to be equal to or higher than the first temperature, and estimates the amount of soot based on the speed of the internal combustion engine, the load parameter, and the second temperature data when determining the temperature parameter to be equal to or lower than the second temperature, and

when determining the temperature parameter to be higher than the second temperature and lower than the first temperature, the soot amount estimator calculates a first temperature soot amount based on the speed of the internal combustion engine, the load parameter, and the first temperature data, calculates a second temperature soot amount based on the speed of the internal combustion engine, the load parameter, and the second temperature data, and estimates the amount of soot by linear interpolation between the first and second temperature soot amounts.