Glow plug control drive method and glow plug drive control system

• US 9,322,384 B2
• Filed: 12/06/2011
• Issued: 04/26/2016
• Est. Priority Date: 12/16/2010
• Status: Active Grant

• Current Assignee: Bosch Corporation (Robert Bosch GmbH)
• Original Assignee: Bosch Corporation (Robert Bosch GmbH)
• Inventors: Hujishiro, Yoshito, Tanaka, Yutaka, Nakamura, Tomohiro
• Primary Examiner(s): Cronin, Stephen K
• Assistant Examiner(s): Steckbauer, Kevin R
• Application Number:
  US13/993,165
• Publication Number:
  US 20130255615A1
• Time in Patent Office: 1,603 Days
• Field of Search: 123/145.A, 123/179.6
• US Class Current: 1/1
• CPC Class Codes: F02D 2041/2027 Control of the current by pulse width modulation or duty cycle control
• CPC Class Codes: F02P 19/02 electric, e.g. layout of circuits of apparatus having glowing plugs
• CPC Class Codes: F02P 19/022 using intermittent current supply
• CPC Class Codes: F02P 19/023 Individual control of the glow plugs
• CPC Class Codes: F02P 19/026 Glow plug actuation during engine operation
• CPC Class Codes: F02P 23/00 Other ignition
• CPC Class Codes: F23Q 7/001 Glowing plugs for internal-combustion engines

Abstract

To suppress current fluctuations upon commencement of driving and prolong lifespan by reducing electric stress caused by current fluctuations.

A glow plug 1, a glow switch 2, and a stabilizing coil 3 are series-connected, and upon commencement of the driving of the glow plug 1, a repetition frequency of PWM signals that control the opening and closing of the glow switch 2 is made into a higher frequency than a repetition frequency in a normal drive state and the opening and closing of the glow switch 2 is controlled (S104), and when a predetermined drive shift condition has been met (S106), the repetition frequency of the PWM signals is returned to the frequency during normal driving and the opening and closing of the glow switch 2 is controlled (S108), whereby the current upon commencement of driving is smoothed and the occurrence of an instantaneous large current is suppressed.

Claims

1. A method of controlling the driving of a glow plug in a glow plug drive control system which enables driving to energize the glow plug, the system comprising:

a glow switch, a stabilizing coil, and a glow plug that are series-connected, a battery voltage being applied to one end of the glow switch, another end of the glow plug connected to a ground; and

an electronic control unit that controls the opening and closing of the glow switch, the method comprising;

in an initial drive state, performing opening and closing of the glow switch, with a first frequency of PWM signals, the initial drive state occurring on commencement of driving the glow plug; and

in a normal drive state, performing opening and closing of the glow switch with a second frequency of PWM signals, the normal drive state occurring when a predetermined drive shift condition has been met;

wherein the first frequency is higher than the second frequency; and

wherein the predetermined drive shift condition is the cumulative energy that has been expended for driving the glow plug since the commencement of the driving of the glow plug, and it is determined that the predetermined drive shift condition has been met when it has been determined that the cumulative energy has reached a predetermined value.

2. The glow plug drive control method according to claim 1, wherein

the predetermined drive shift condition is the amount of elapsed time since the commencement of driving, and

it is determined that the predetermined drive shift condition has been met when the amount of elapsed time has reached a predetermined amount of elapsed time.

3. The glow plug drive control method according to claim 1, wherein when Vg represents the voltage applied to the glow plug and t represents the amount of elapsed time since the commencement of driving, the cumulative energy is expressed as Vg²×

t.

4. The glow plug drive control method according to claim 1, wherein when Vg represents the voltage applied to the glow plug and Ig represents the energizing current of the glow plug, the cumulative energy is expressed as ∫

Vg(t)×

Ig(t)dt.

5. A glow plug drive control system which enables driving to energize a glow plug, the system comprising:

a glow switch, a stabilizing coil, and a glow plug that are series-connected, a battery voltage being applied to one end of the glow switch, another end of the glow plug being connected to a ground; and

an electronic control unit that controls the opening and closing of the glow switch,

wherein the electronic control unit is configured to perform opening and closing of the glow switch in an initial drive state with a first frequency of PWM signals, the initial drive state occurring on commencement of driving the glow plug; and

perform opening and closing of the glow switch in a normal drive state with a second frequency of PWM signals, the normal drive state occurring when a predetermined drive shift condition has been met;

wherein the first frequency is higher than the second frequency; and

wherein the predetermined drive shift condition is the cumulative energy that has been expended for driving the glow plug since the commencement of the driving of the glow plug, and it is determined that the predetermined drive shift condition has been met when it has been determined that the cumulative energy has reached a predetermined value.

6. The glow plug drive control system according to claim 5, wherein the predetermined drive shift condition is the amount of elapsed time since the commencement of driving, and the electronic control unit is configured to judge that the predetermined drive shift condition has been met when it has been determined that the amount of elapsed time has reached a predetermined amount of elapsed time.

7. The glow plug drive control system according to claim 5, wherein when Vg represents the voltage applied to the glow plug and t represents the amount of elapsed time since the commencement of driving, the cumulative energy is expressed as Vg²×

t.

8. The glow plug drive control system according to claim 5, wherein when Vg represents the voltage applied to the glow plug and Ig represents the energizing current of the glow plug, the cumulative energy is expressed as ∫

Vg(t)×

Ig(t)dt.