GLOW PLUG TIP TEMPERATURE ESTIMATING METHOD AND GLOW PLUG DRIVE CONTROL DEVICE

• US 20120175360A1
• Filed: 01/12/2012
• Published: 07/12/2012
• Est. Priority Date: 01/12/2011
• Status: Active Grant

• Current Assignee: Bosch Corporation (Robert Bosch GmbH)
• Original Assignee: Bosch Corporation (Robert Bosch GmbH)
• Inventors: Toyoshima, Yasuo, Takatsu, Katsumi
• Granted Patent: US 9,255,564 B2
• Time in Patent Office: Days
• US Class Current: 219/264
• CPC Class Codes: F02D 41/2451 characterised by what is learned or calibrated
• CPC Class Codes: F02P 19/025 with means for determining glow plug temperature or glow plug resistance

Abstract

An arithmetic and control unit is configured to calculate a resistance value of a glow plug on the basis of an energization current of the glow plug and a voltage applied to the glow plug, perform a multiplication of the resistance value and a constant that has been determined beforehand on the basis of an electrical characteristic of the glow plug, input a predetermined heater reference point temperature, calculate an offset with a predetermined offset arithmetic expression from the heater reference point temperature, correct the multiplication result with that offset, and take the correction result as an estimated temperature of a tip of the glow plug.

Claims

1. A glow plug tip temperature estimating method comprising:

correcting, with an offset that has been obtained on the basis of a predetermined heater reference point temperature, the result of multiplying a measured resistance value of a glow plug and a constant determined on the basis of an electrical characteristic of the glow plug; and

taking the result of the correction as an estimated temperature of the tip of the glow plug.

2. The glow plug tip temperature estimating method according to claim 1, wherein:

the predetermined heater reference point temperature is the temperature of an arbitrary site excluding the neighborhood of a heating element of the glow plug, and

the offset is a value that offsets a drift resulting from a change in the heater reference point temperature that arises in the result of multiplying the measured resistance value of the glow plug and the constant determined on the basis of the electrical characteristic of the glow plug, the offset obtained by an arithmetic expression that has been determined such that the offset is calculated as a function of the heater reference point temperature.

3. The glow plug tip temperature estimating method according to claim her comprising:

substituting, as the temperature of the arbitrary site excluding the neighborhood of the heating element of the glow plug, an output of a sensor installed in a vehicle; and

obtaining, based on a predetermined correlation between the sensor output and the temperature of the arbitrary site excluding the neighborhood of the heating element of the glow plug, the temperature of the arbitrary site excluding the neighborhood of the heating element of the glow plug that corresponds to the sensor output.

4. A glow plug drive control device comprising:

an arithmetic and control unit that executes a drive control of a glow plug; and

an energization drive circuit that performs energization of the glow plug in response to the drive control of the glow plug executed by the arithmetic and control unit,

wherein the arithmetic and control unit is configured to arithmetically calculate a resistance value of the glow plug based on an energization current of the glow plug and a voltage applied to the glow plug, perform a multiplication of a calculated resistance value of the glow plug and a predetermined constant based on an electrical characteristic of the glow plug, input a predetermined heater reference point temperature, calculate an offset with a predetermined offset arithmetic expression from the heater reference point temperature, correct the multiplication result with the offset, and calculate an estimated temperature of a tip of the glow plug.

5. The glow plug drive control device according to claim 4, wherein:

the predetermined heater reference point temperature is the temperature of an arbitrary site excluding the neighborhood of a heating element of the glow plug, and

the offset arithmetic expression is determined such that a value that offsets a drift resulting from a change in the heater reference point temperature that arises in the result of multiplying the resistance value of the glow plug that has been actually measured and the predetermined constant based on the electrical characteristic of the glow plug is calculated as a function of the heater reference point temperature.

6. The glow plug drive control device according to claim 5, wherein the arithmetic and control unit is further configured to be capable of:

inputting, as the temperature of the arbitrary site excluding the neighborhood of the heating element of the glow plug, an output of a sensor that is installed in a vehicle; and

calculating, on the basis of a predetermined correlation between the sensor output and the temperature of the arbitrary site excluding the neighborhood of the heating element of the glow plug, the temperature of the arbitrary site excluding the neighborhood of the heating element of the glow plug that corresponds to the sensor output.