Method for determining the oil temperature in an internal combustion engine

• US 7,069,141 B2
• Filed: 04/04/2002
• Issued: 06/27/2006
• Est. Priority Date: 04/23/2001
• Status: Expired due to Fees

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Zhang, Hong, Kunz, Franz
• Primary Examiner(s): Vo, Hieu T.
• Application Number:
  US10/475,736
• Publication Number:
  US 20040128059A1
• Time in Patent Office: 1,545 Days
• Field of Search: 701/114, 701/101, 701/115, 701/102, 701/30, 701/29
• US Class Current: 701/114
• CPC Class Codes: F01M 1/18 Indicating or safety devices concerning lubricant level F01M11/06, F01M11/12
• CPC Class Codes: F01M 11/10 Indicating devices; Other safety devices
• CPC Class Codes: F01M 5/005 Controlling temperature of lubricant
• CPC Class Codes: F02D 2200/023 Temperature of lubricating oil or working fluid

Abstract

The oil temperature in the internal combustion engine is calculated using an oil temperature model, which draws upon at least one parameter that characterizes the operating point of the internal combustion engine. The differential value between the modeled temperature value of the oil temperature model and the measured temperature value of the oil, which is measured by the oil temperature sensor, is included as an input variable in the oil temperature model during an iterative calculation cycle of an oil temperature value of the oil temperature mode, said calculation cycle directly or indirectly following the method step involving the calculation of the differential value.

Claims

1. A method of determining the oil temperature in an internal combustion engine, comprising the steps of:

inputting at least one parameter characterizing the operating point of the internal combustion engine to a controller having an oil temperature model;

determining, by the oil temperature model in the controller, a modeled oil temperature sensor value based on the at least one parameter;

measuring an oil temperature value;

comparing the modeled oil temperature sensor value with the measured oil temperature value to calculate a differential value;

including the differential value as an input to the oil temperature model; and

reiteratively determining, by the oil temperature model in the controller, another modeled oil temperature sensor value in a reiterative calculation cycle based on the at least one parameter and the differential value.

2. The method of claim 1, wherein said step of measuring an oil temperature value comprises using an oil temperature sensor.

3. The method of claim 2, further comprising the step of detecting an oil temperature sensor malfunction if the differential value exceeds a first temperature threshold value or is below a second temperature threshold value.

4. The method of claim 3, further comprising the step of at least one of generating a signal and placing an entry in a fault memory of a memory unit connected to the controller when an oil temperature sensor malfunction is detected, the signal being one of a visual signal and an audio signal.

5. The method of claim 1, wherein said differential value is additively or multiplicatively included in the oil temperature model.

6. The method of claim 1, wherein the at least one parameter includes at least one of coolant temperature, air mass flow, intake pipe pressure, and excess air ratio.