Automotive engine oil monitoring system

• US 4,677,847 A
• Filed: 09/30/1985
• Issued: 07/07/1987
• Est. Priority Date: 09/30/1985
• Status: Expired due to Fees

• Current Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.)
• Original Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.)
• Inventors: Sugiura, Toshihiro, Nakamura, Mitsutaka, Sawatari, Takeo
• Primary Examiner(s): Tokar, Michael J.
• Assistant Examiner(s): Raevis, Robert R.
• Application Number:
  US06/781,501
• Time in Patent Office: 645 Days
• Field of Search: 73/118, 73/53, 73/64, 73/117.3, 340/59
• US Class Current: 73/53.05
• CPC Class Codes: F01M 2011/14 for indicating the necessity to change the oil
• CPC Class Codes: F01M 2011/142 by considering speed, e.g. revolutions per minute [RPM]
• CPC Class Codes: F01M 2011/1473 by considering temperature
• CPC Class Codes: G01N 33/2888 Lubricating oil characteristics, e.g. deterioration lubricating properties G01N33/30

Abstract

The present invention describes a method and apparatus for monitoring and indicating engine oil deterioration during the period of the oil'"'"'s useful life in an internal combustion engine. The system and method permits a determination of the rate of deterioration of the engine oil as a function of oil temperature or RPM of the engine and provides a continous output signal representing the remaining useful life of the oil which is provided to the driver when desired. The present invention therefore, estimates the time when the oil will reach an undesirable deterioration level during the course of operation of the engine rather than indicating, as many prior art systems, only when the oil reaches an undesirable level requiring an oil change.

Claims

1. A method for continuously monitoring and indicating engine oil deterioration during the period of the oil'"'"'s useful life in an internal combustion engine comprising the steps of:

generating a signal representative of engine oil temperature;

determining the rate of the deterioration of said oil as a function of oil temperature;

generating a signal representative of elapsed engine running time;

generating a signal representative of actual elapsed time since the oil was changed;

determining a first remaining useful life (M_R) of said oil as a function of said rate of deterioration and said elapsed engine running time from the expression;

##EQU6## where ##EQU7## t=elapsed engine running time T=oil temperature

α

=oil deterioration rate

and producing a continuous output signal representative of said first remaining useful life;

determining a second remaining useful life of said oil as a function of said rate of deterioration and said actual elapsed time and producing a continuous output signal representative of said second remaining useful life;

selecting either the continuous output signal from said elapsed engine running time and said rate of deterioration or the continuous output signal produced from said actual elapsed time and said rate of deterioration; and

indicating the remaining useful life as a function of the selected output signal.

2. The method of claim 1 wherein the second remaining useful life (M_r) is determined from the expression:

##EQU8## where;

##EQU9## where;

τ

=actual elapsed time

α

=oil deterioration rate.

3. A system for continuously monitoring and indicating engine oil deterioration during the period of the oil'"'"'s useful life in an internal combustion engine comprising:

temperature signal generating means for generating a signal representative of engine oil temperature;

deterioration rate measuring means coupled to said temperature signal generating means for determining the rate of deterioration of said oil as a function of oil temperature;

engine running time measuring means for generating a signal representative of elapsed engine running time;

time measuring means for generating a signal representative of actual elapsed time since the oil was changed;

a first remaining useful life determining means coupled to said deterioration rate determining means and said engine running time measuring means for determining the first remaining useful life (M_R) in accordance with the following expression;

##EQU10## where ##EQU11## t=elapsed engine running time T=oil temperature

α

=oil deterioration rate,

and producing a continuous output signal representative of said first remaining useful life;

a second remaining useful life determining means coupled to said deterioration rate determining means and said time measuring means for determining the second remaining useful life of said oil as a function of said deterioration rate and said actual elapsed time and producing a continuous output signal representative of said second remaining useful life;

signal selecting means for selecting either the output signal from the first remaining useful life determining means or the output signal from the second remaining useful life determining means; and

indicating means coupled to said remaining useful life determining means for indicating the remaining useful life as a function of the selected output signal.

4. The system of claim 3 wherein the second remaining useful life (M_r) is determined from the expression:

##EQU12## where;

##EQU13## where;

τ

=actual elapsed time

α

=oil deterioration rate.

5. A method for continuously monitoring and indicating engine oil deterioration during the period of the oil'"'"'s life in an internal combustion engine comprising the steps of:

generating a signal representative of engine oil temperature;

determining the rate of the deterioration of said oil as a function of oil temperature;

generating a signal representative of elapsed engine running time;

generating a signal representative of actual elapsed time since the oil was changed;

determining a first remaining useful life (M_R) of said oil as a function of said rate of deterioration and said elapsed engine running time from the expression;

##EQU14## where ##EQU15## t=elapsed engine running time T=oil temperature

α

=oil deterioration rate

M=a constant representative of average mileage of an automobile in miles/hour

and producing a continuous output signal representative of said first remaining useful life;

determining a second remaining useful life of said oil as a function of said rate of deterioration and said actual elapsed time and producing a continuous output signal representative of said second remaining useful life;

selecting either the continuous output signal from said elapsed engine running time and said rate of deterioration or the continuous output signal produced from said actual elapsed time and said rate of deterioration; and

indicating the remaining useful life as a function of the selected output signal.

6. The method of claim 5 wherein the second remaining useful life (M_r) is determined from the expression:

space="preserve" listing-type="equation">M.sub.r =(B-τ

)×

M'"'"',

where ##EQU16## c=a constant representative of the oil'"'"'s normal useful life β

=reduction rate of the useful life of the oil derived from the oil deterioration rate

t=elapsed engine running time

τ

=actual elapsed time

M'"'"'=a constant representative of average mileage of an automobile in miles/month.

7. A system for continuously monitoring and indicating engine oil deterioration during the period of the oil'"'"'s useful life in an internal combustion engine comprising:

temperature signal generating means for generating a signal representative of engine oil temperature;

deterioration rate measuring means coupled to said temperature signal generating means for determining the rate of deterioration of said oil as a function of oil temperature;

engine running time measuring means for generating a signal representative of elapsed engine running time;

time measuring means for generating a signal representative of actual elapsed time since the oil was changed;

a first remaining useful life determining means coupled to said deterioration rate determining means and said engine running time measuring means for determining the first remaining useful life (M_R) in accordance with the following expression;

##EQU17## where ##EQU18## t=elapsed engine running time T=oil temperature

α

=oil deterioration rate

M=a constant representative of average mileage of an automobile in miles/hour,

and producing a continuous output signal representative of said first remaining useful life;

a second remaining useful life determining means coupled to said deterioration rate determining means and said time measuring means for determining the second remaining useful life of said oil as a function of said deterioration rate and said actual elapsed time and producing a continuous output signal representative of said second remaining useful life;

signal selecting means for selecting either the output signal from the first remaining useful life determining means or the output signal from the second remaining useful life deterining means; and

indicating means coupled to said remaining useful life determining means for indicating the remaining useful life as a function of the selected output signal.

8. The system of claim 7 wherein the second remaining useful life (M_r) is determined from the expression:

space="preserve" listing-type="equation">M.sub.r =(B-τ

)×

M'"'"',

where ##EQU19## C=a constant representative of the oil'"'"'s normal useful life β

=reduction rate of the useful life of the oil derived from the oil deterioration rate

t=elapsed engine running time

τ

=actual elapsed time

M'"'"'=a constant representative of average mileage of an automobile in miles/month.