Method for the recognition of oil top-up quantities

• US 6,009,361 A
• Filed: 08/18/1997
• Issued: 12/28/1999
• Est. Priority Date: 08/17/1996
• Status: Expired due to Fees

• Current Assignee: DaimlerChrysler AG (Mercedes-Benz Group AG)
• Original Assignee: DaimlerChrysler AG (Mercedes-Benz Group AG)
• Inventors: Pilsl, Juergen, Huber, Bernd
• Primary Examiner(s): LOUIS JACQUES, JACQUES H
• Application Number:
  US08/912,619
• Time in Patent Office: 862 Days
• Field of Search: 701/29, 701/30, 701/31, 73/53.05, 73/117.3, 73/116, 73/291, 73/302, 73/293, 123/196 AB, 123/142.5 R, 123/73 AD, 123/198 D, 123/196 S, 340/457.4, 340/438, 340/439, 340/459, 340/449
• US Class Current: 701/29
• CPC Class Codes: F01M 11/061 Means for keeping lubricant level constant
• CPC Class Codes: F01M 11/12 concerning lubricant level
• CPC Class Codes: F01M 2011/14 for indicating the necessity to change the oil
• CPC Class Codes: G01F 23/802 Particular electronic circuits for digital processing equipment

Abstract

A method for recognizing oil top-up quantities is provided. The method records a multiplicity of oil levels under specific operating conditions over time; calculates an oil-mass average value X_z of the oil top-up quantity over z instantaneous measurements xmom in each case; calculates a compensating function describing the variation in an oil mass xh over time using a specific number of hourly oil masses xh; calculates a difference DFA from an end point xlang of the compensating function and from the penultimate oil-mass average value according to a function activates a discrimination function for checking whether the difference DFA is greater than a first oil-mass limit value M1; and if so, a special case is recognized and a processing function for calculating the oil top-up quantity in the special case is started; and if not, a further discrimination function is started, for checking whether the difference DFA is greater than a second oil-mass limit value M2 and there is a specific communication signal between the vehicle and driver. If the result of the check is that the difference DFA is greater than the second oil-mass limit value M2, a special case is recognized and the processing function for calculating the oil top-up quantity in the special case is started. If the interrogation result is negative, a processing function for calculating the oil top-up quantity in the normal case is activated.

Claims

1. A method for recognizing oil top-up quantities in an engine, the method comprising the steps of:

a) recording a multiplicity of oil levels under specific operating conditions over time;

b) calculating an oil-mass average value X_z of the oil top-up quantity over z instantaneous measurements xmom in each case;

c) calculating a compensating function, describing a variation in an oil mass xh over time, using a specific number of hourly oil masses xh;

d) calculating a difference value DFA from an end point xlang of said compensating function and from a penultimate oil-mass average value according to a function (DFA=xlang-X_zN-1), with X_zN-1 being an oil mass penultimately obtained by rolling averaging from z instantaneous oil masses xmom;

e) activating a discrimination function for checking whether said difference value DFA is greater than a first oil-mass limit value M1; and

if so, a first case is recognized and a processing function for calculating the oil top-up quantity in the first case is started; and

if not, a further discrimination function is activated, for checking whether the difference value DFA is greater than a second oil-mass limit value M2 and for checking if there is a specific communication signal between the vehicle and driver such that if a result of the check is that the difference value DFA is greater than the second oil-mass limit value M2 and there is a specific communication signal between the vehicle and driver, a second case is recognized and the processing function for calculating the oil top-up quantity in the second case is started, and if the result is negative, a processing function for calculating the oil top-up quantity in a normal case is activated.

2. The method according to claim 1, wherein to calculate the oil top-up quantity in the normal case, the method comprises the step of forming the difference value DNF according to the function (DNF=X_zN -xlang) from a most current oil-mass average value X_zN and an end point xlang of the compensating function describing the variation in the oil mass xh over time.

3. The method according to claim 2, wherein in a reliabilty interrogation, the method includes the step of recognizing the difference DNF as valid if it is greater than a further oil-mass limit value M5.

4. The method according to claim 1, wherein to calculate the oil top-up quantity in either the first or second case, a difference DS is formed according to the function (DS=X_zN -X_zN-1).

5. The method according to claim 4, wherein in a reliability interrogation, the method includes the step of recognizing the difference DS as valid if it is greater than a further oil-mass limit value M4 and a most current oil-mass average value X_zN fulfills a predeterminable quality as regards a distribution of fundamental individual values xmom.

6. The method according to claim 5, wherein the most current oil-mass average value X_zN has a standard deviation sX_zN lower than a predetermined oil-mass limit value M3, which represents a statistical limit value for describing the spread.

7. The method according to claim 1, wherein the compensating function represents a straight line of regression.

8. The method according to claim 1, wherein the number z of measurements for forming an average value X_z of the oil quantity is between 10 and 60 measurements.

9. The method according to claim 8, wherein the number Z of measurements is thirty.

10. The method according to claim 1, wherein the number of instantaneous measurements xmom is variable, a time interval T, in which the measurements are carried out, being predetermined.

11. The method according to claim 10, wherein the predetermined time interval T is 20 to 120 minutes.

12. The method according to claim 11, wherein the predetermined time interval is 60 minutes.

13. The method according to claim 1, wherein the oil-mass limit value M1 is higher than the oil-mass limit value M2 and the oil-mass limit value M4 is higher than the oil-mass limit value M5.

14. The method according to claim 13, wherein:

M₁ =0.4 kg and/or;

M₂ =0.2 kg and/or;

M₃ =0.18 kg and/or;

M₄ =0.55 kg and/or;

M₅ =0.44 kg.

15. A computer product, comprising:

a computer readable medium having stored thereon a program for recognizing oil top-up quantities in an engine, said program including code segments that;

a) record a multiplicity of oil levels under specific operating conditions over time;

b) calculate an oil-mass average value X_z of the oil top-up quantity over z instantaneous measurements xmom in each case;

c) calculate a compensating function, describing a variation in an oil mass xh over time, using a specific number of hourly oil masses xh;

d) calculate a difference value DFA from an end point xlang of said compensating function and from a penultimate oil-mass average value according to a function (DFA=xlang-X_zN-1), with X_zN-1 being an oil mass pen ultimately obtained by rolling averaging from z instantaneous oil masses xmom;

e) activate a discrimination function for checking whether said difference value DFA is greater than a first oil-mass limit value M1; and

if so, a first case is recognized and a processing function for calculating the oil top-up quantity in the first case is started; and

if not, a further discrimination function is activated, for checking whether the difference value DFA is greater than a second oil-mass limit value M2 and for checking if there is a specific communication signal between the vehicle and driver such that if a result of the check is that the difference value DFA is greater than the second oil-mass limit value M2 and there is a specific communication signal between the vehicle and driver, a second case is recognized and the processing function for calculating the oil top-up quantity in the second case is started, and if the result is negative, a processing function for calculating the oil top-up quantity in a normal case is activated.

16. The computer product according to claim 15, wherein the program include'"'"'s code segments to calculate the oil top-up quantity in the normal case by forming the difference value DNF according to the function (DNF=X_zN -xlang) from a most current oil-mass average value X_zN and an end point xlang of the compensating function describing the variation in the oil mass xh over time.

17. The computer product according to claim 16, wherein the program includes code segments, which, in a reliabilty interrogation, recognize the difference DNF as valid if it is greater than a further oil-mass limit value M5.