Automotive engine oil monitoring system

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.sub.R) in accordance with the following expression:
• ##EQU10## where ##EQU11## t=elapsed engine running time T=oil temperature
• .alpha.=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.

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.sub.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
• .alpha.=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.

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.sub.R) in accordance with the following expression:
• ##EQU17## where ##EQU18## t=elapsed engine running time T=oil temperature
• .alpha.=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.