Method for controlling the power supply of a pre-heat plug in an internal combustion engine

• US 7,899,609 B2
• Filed: 12/21/2007
• Issued: 03/01/2011
• Est. Priority Date: 12/22/2006
• Status: Active Grant

• Current Assignee: Renault Sas (Renault)
• Original Assignee: Renault Sas (Renault)
• Inventors: Rodrigues, Juan Miguel, Palanque, Nicolas
• Primary Examiner(s): Huynh; Hai H
• Application Number:
  US12/520,637
• Publication Number:
  US 20100063705A1
• Time in Patent Office: 1,166 Days
• Field of Search: 123/406.55, 123/145.A, 123/145.R, 123/179.6, 701/112, 701/113
• US Class Current: 701/112
• CPC Class Codes: F02D 35/025 by determining temperatures inside the cylinder, e.g. combustion temperatures
• CPC Class Codes: F02D 41/042 for stopping the engine
• CPC Class Codes: F02P 19/022 using intermittent current supply
• CPC Class Codes: F02P 19/025 with means for determining glow plug temperature or glow plug resistance

Abstract

A method for controlling power supply of a pre-heat plug in an internal combustion engine to reach an ignition temperature for restarting the engine after the engine has stopped. The temperature of the pre-heat plug is determined using a first mathematical model and according to an elapsed engine-stop time, and additional energy to be supplied to the pre-heat plug for reaching the ignition temperature is determined using a second mathematical model and according to the temperature of the pre-heat plug.

Claims

1. A method for controlling supply of electrical power to a pre-heater plug of an internal combustion engine, to reach an ignition temperature so that the engine can be restarted after the engine has been stopped, the method comprising:

a) determining temperature of the pre-heater plug using a first mathematical model and as a function of time that has elapsed since the engine was stopped; and

b) determining additional energy to be supplied to the pre-heater plug to reach the ignition temperature using a second mathematical model, as a function of the temperature of the pre-heater plug and of the temperature of the combustion chamber surrounding the pre-heater plug.

2. The method as claimed in claim 1, wherein the first mathematical model is a characteristic law governing drop in temperature of the pre-heater plug.

3. The method as claimed in claim 1, wherein the second mathematical model is a characteristic law governing increase in temperature of the pre-heater plug.

4. The method as claimed in claim 1, wherein the additional energy is converted by an engine computer into an additional heating time.

5. The method as claimed in claim 4, wherein the computer calculates, from the additional heating time, a correction factor that needs to be applied to a reference heating time.

6. The method as claimed in claim 5, wherein the correction factor is also calculated as a function of the temperature of the combustion chamber of the engine.

7. The method as claimed in claim 4, wherein the reference heating time is the heating time that needs to be applied to a pre-heater plug, the temperature of which has, after the engine was stopped, reached its minimum value, for the pre-heater plug once again to reach the ignition temperature.

8. The method as claimed in claim 1, wherein the pre-heater plug is a low-voltage pre-heater plug.

9. The method as claimed in claim 1, wherein, after the determining b), the determined amount of additional energy is delivered to the pre-heater plug in electric voltage pulses using a pulse width modulation.