APPARATUS FOR CONTROLLING THE ENERGIZING OF A HEATER

• US 20100161150A1
• Filed: 11/23/2009
• Published: 06/24/2010
• Est. Priority Date: 11/25/2008
• Status: Active Grant

• Current Assignee: NGK Spark PLUG Company Limited
• Original Assignee: NGK Spark PLUG Company Limited
• Inventors: SAKURAI, Takayuki, Ohtani, Takayuki, Tsuchiya, Hiroki
• Granted Patent: US 8,423,197 B2
• Time in Patent Office: Days
• US Class Current: 700/296
• CPC Class Codes: F02D 41/042 for stopping the engine
• CPC Class Codes: F02D 41/2464 Characteristics of actuators
• CPC Class Codes: F02P 19/025 with means for determining glow plug temperature or glow plug resistance
• CPC Class Codes: F02P 19/027 Safety devices, e.g. for diagnosing the glow plugs or the related circuits

Abstract

[Object] To provide a heater energization control apparatus which can detect that a heater has been exchanged.

[Means for Solution] When an engine is stopped, a microcomputer of a GCU enters a power save mode. When the microcomputer returns to a normal mode in response to an interruption signal periodically generated from an interruption timer, the microcomputer supplies electricity to a heating resistor for a short time and obtains its resistance (S19). When the resistance is greater than a first reference value, the microcomputer determines that a glow plug is removed from the engine; that is, the glow plug is being exchanged (S29). The microcomputer sets an exchange flag to “1” (S30), and performs calibration for the heating resistor of a new glow plug after the engine is operated next time (S35). Further, since the resistance of the heating resistor changes (increases) with deterioration of the heating resistor with time, the acquired resistance may be stored. When the current resistance becomes smaller than the past resistance, the microcomputer determines that the glow plug has been exchanged.

Claims

1. A heater energization control apparatus for controlling energization of a heater having a heating resistor which generates heat upon supply of electricity thereto, the apparatus comprising:

first resistance acquisition means, operable when an internal combustion engine to which the heater is mounted remains stopped, for supplying electricity to the heating resistor every time a predetermined wait time elapses and for acquiring, as a first resistance, an electricity supply resistance at that time; and

determination means for determining that the heater has been exchanged, when the first resistance is greater than a predetermined first reference value.

2. A heater energization control apparatus according to claim 1, wherein the wait time is shorter than a predetermined time required to exchange the heater mounted to the internal combustion engine.

5. A heater energization control apparatus according to any one of claims 1 to 4, wherein a cumulative amount of electric power which is supplied to the heating resistor when the first resistance acquisition means acquires the first resistance is determined such that a temperature of the heating resistor elevated through the supply of electric power drops to a temperature of the heating resistor before being supplied with the electric power due to natural heat radiation until the first resistance is acquired next time.

6. A heater energization control apparatus according to any one of claims 1 to 5, further comprising first setting means for setting an operation clock of the heater energization control apparatus to generate clock pulses at a first frequency when the internal combustion engine remains stopped, and setting the operation clock to generate clock pulses at a second frequency higher than the first frequency when the first resistance acquisition means acquires the first resistance.

7. A heater energization control apparatus according to any one of claims 1 to 6, wherein

the heating resistor is a heating resistor whose resistance changes with a temperature change thereof in accordance with a positive correlation between the temperature and the resistance;

the heater energization control apparatus is configured to control the supply of electricity to the heating resistor in accordance with a resistance control scheme in which the supply of electricity to the heating resistor is controlled such that the resistance of the heating resistor coincides with a target resistance; and

the heater energization control apparatus comprises;

second resistance acquisition means for supplying electricity to the heating resistor when the internal combustion engine is first operated after the heater is determined by the determination means to have been exchanged and then stopped, and for acquiring, as a second resistance, the electricity supply resistance at that time;

second information acquisition means, operable when the second resistance is acquired, for acquiring information regarding the temperature of the environment in which the heater is used;

second computation means for computing the target resistance on the basis of the second resistance and the information regarding the environmental temperature; and

energization control means, operable when the internal combustion engine is operated, for controlling the supply of electricity to the heating resistor such that the electricity supply resistance at the time when electricity is supplied to the heating resistor coincides with the target resistance.

8. A heater energization control apparatus according to claim 7, further comprising second setting means, operable after the determination means determines that the heater has been exchanged, for setting the second resistance to its initial value before the energization control means starts the control of the first supply of electricity to the heating resistor.

9. A heater energization control apparatus according to claim 7, further comprising deterioration detection means for detecting deterioration of the heating resistor on the basis of the first resistance, wherein

when deterioration of the heating resistor is detected by the deterioration detection means, every time the internal combustion engine is stopped, the second resistance acquisition means acquires the second resistance and the second computation means calculates the target resistance.

10. A heater energization control apparatus according to any one of claims 7 to 9, wherein the supply of electricity to the heating resistor by the second resistance acquisition means is performed in accordance with a constant power control scheme such that the cumulative electric energy supplied to the heating resistor becomes equal to a predetermined electric energy.

11. A heater energization control apparatus according to any one of claims 1 to 10, wherein the heater constitutes a heat generation section of a glow plug mounted to the internal combustion engine for use.

3. A heater energization control apparatus for controlling energization of a heater having a heating resistor which generates heat upon supply of electricity thereto, the apparatus comprising:

first resistance acquisition means, operable when an internal combustion engine to which the heater is mounted remains stopped, for supplying electricity to the heating resistor and for acquiring, as a first resistance, an electricity supply resistance at that time;

first information acquisition means, operable when the first resistance is acquired, for acquiring information regarding a temperature of an environment in which the heater is used;

correction means for correcting the first resistance on the basis of the information regarding the environmental temperature to thereby obtain a corrected value;

first computation means for computing a difference between a current corrected value obtained by the correction means and a past corrected value previously obtained by the correction means;

determination means for determining that the heater has been exchanged, when the difference is greater than a predetermined second reference value; and

storage means for storing, as the past corrected value, the current corrected value obtained by the correction means.

4. A heater energization control apparatus according to claim 3, wherein, when the past corrected value stored in the storage means is an initial value or zero, the determination means determines that the heater has been exchanged.