JP2012017733A - Glow plug energization control system and method of controlling the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a glow plug energization control system which controls glow plugs, provided for every cylinder, without incurring the multi-porting of an ECU or the complication of wiring, by a glow plug energization controller.SOLUTION: An ECU3 and a plurality of GCU100are coupled with each other by using a drive command signal line WIR, which transmits a drive command signal SI from the ECU3 to each GCU100, and a self diagnosis signal line WIR, which transmits a self diagnosis signal from each GCU100to ECU3, and also it includes a cylinder position determining means IDU120, which determines the position of its own cylinder by forming a resistance ladder circuit by a voltage difference detecting resistor 122 and a voltage detecting resistor 127 which are provided in each GCU100between ECU3 and each GCU100, in a cylinder position determination mode.

Description

  The present invention relates to a glow plug energization control system for controlling energization to a glow plug provided for each cylinder of a diesel combustion engine having a plurality of cylinders by an individual glow plug energization control device and a control method therefor.

  Conventionally, as a glow plug energization control device (hereinafter abbreviated as GCU) for controlling energization of a glow plug that assists ignition of a diesel combustion engine, a switching element has been provided between the glow plug and a power source, depending on the operating condition of the engine. In accordance with a drive command signal transmitted from the ECU, the one that opens and closes the switching element to control the energization to the glow plug is known (see, for example, Patent Documents 1 and 2).

In recent years, low-rated ceramic glow plugs that supply a large current and enable rapid temperature rise have been used. With this, the amount of heat generated by the switching elements that control the energization of the glow plugs has also increased. It tends to increase.
However, in the conventional GCU, a plurality of glow plugs are controlled by providing a plurality of switching elements in one GCU, and a device for improving heat dissipation and reducing the influence of heat generated from the plurality of switching elements. May increase in size.

In addition, the diesel combustion engine is provided with a battery voltage, an engine water temperature sensor, a tachometer, and the like as an operation state detection means for detecting an operation state, and according to the operation state based on information from these sensors. In order to control energization of the glow plug, a drive command signal (SI) is transmitted from the engine control unit (hereinafter abbreviated as ECU) to the GCU.
On the other hand, the GCU is provided with a failure diagnosis device that detects an abnormality of the glow plug or GCU and notifies the ECU of the abnormality, and a self-diagnosis signal (DI) is transmitted from the GCU to the ECU.
Furthermore, not only the pre-glow for improving the ignitability at start-up, but also an after-glow that energizes the glow plug during operation of the diesel combustion engine to improve exhaust purification performance. Therefore, more accurate energization control to the glow plug and long-time energization control according to the situation are desired.

For this reason, if it is attempted to detect abnormalities in a plurality of glow plugs at an early stage, the amount of data to be processed becomes enormous, and it becomes necessary to improve the performance of the microcomputer used in the GCU.
Conventionally, since communication is performed for each cylinder using a communication protocol such as KWP (Key Word Protocol) or a token method, there is a problem that a communication response takes time and a system configuration becomes complicated.

  Therefore, in response to these problems, by providing a GCU separately for each glow plug provided for each cylinder of a diesel combustion engine composed of a plurality of cylinders, downsizing of the apparatus by reducing the heat generation amount for each GCU, It is conceivable to improve the control.

However, if the configuration of the conventional GCU is provided in each glow plug as it is, it is necessary to increase the number of communication ports on the ECU side, which leads to complication of wiring and an increase in manufacturing cost.
In addition, when energization to a plurality of glow plugs is controlled by one GCU, the position of each glow plug can be recognized by the GCU, but the GCU remains in the same configuration as the conventional GCU. If it is provided on or near the glow plug and is individually controlled, it is not possible to recognize which cylinder each GCU is provided, and there is a possibility that it is not possible to perform energization control or abnormality diagnosis for each cylinder. is there.

  Therefore, in view of such a situation, the present invention controls energization to a glow plug provided for each cylinder of a diesel combustion engine having a plurality of cylinders without increasing the number of ports of an engine control device or complicating wiring. Provided with a glow plug energization control system that enables each glow plug energization control device to recognize its own cylinder position and perform energization control and self-diagnosis for each cylinder when performing with an individual glow plug energization control device The purpose is to do.

  In the first invention, switching means provided between a glow plug provided for each cylinder of a diesel combustion engine and a power source is opened and closed based on a drive command signal transmitted from an engine control device that controls the operation of the engine. A glow plug energization control system for driving and controlling energization to the glow plug, comprising a plurality of glow plug energization control devices for individually controlling energization to the glow plug, the glow plug energization control The apparatus includes at least a drive control unit that controls opening and closing of the switching unit based on the drive command signal, a cylinder position determination unit that determines its own cylinder position, and detects a malfunction of the glow plug and transmits a self-diagnosis signal. A self-diagnostic unit, and the engine control device and each glow plug energization control device as the cylinder position determination means A cylinder discriminating resistor is interposed either on the inner side of the drive control unit or on the inner side of the connector connecting the communication wiring and the drive control unit on the communication wiring path for connecting the drive command signals. (Claim 1).

  According to the first aspect of the present invention, it becomes possible to recognize the position of its own cylinder from the resistance value of the cylinder discrimination resistance that changes in accordance with the cylinder position, and the glow plug energization control device provided for each cylinder enables individual glow positions to be recognized. Individual control corresponding to the difference in individual manufacturing and deterioration of plugs is possible, and when an abnormality is detected, the cylinder position is specified and self-diagnosis is carried out. It becomes possible to specify the cylinder and use the self-diagnosis result.

  In the second invention, self-diagnosis signals transmitted from the glow plug energization control device provided for each cylinder of the engine are connected to each other by a wired OR circuit connected to a power supply voltage via a pull-up resistor. According to the self-cylinder recognized by the position determining means, the output bit of each self-diagnosis signal is changed and output, and transmitted to the engine control device as a group of data frames synthesized by the wired OR circuit. 2).

  According to the second aspect of the present invention, the self-diagnosis signal transmitted to the engine control device is a self-cylinder in which each glow plug energization control device independently diagnoses an abnormality and recognizes only the result by the cylinder position determination means. When a signal is transmitted at a timing according to the position, each self-diagnosis signal is output to the corresponding bit, and is combined into a single piece of data by the wired OR circuit and transmitted to the engine control unit. While minimizing the size of data sent from the plug energization control device to the engine control device, it is possible to reliably transmit in which cylinder an abnormality has occurred.

  More specifically, in the third invention, the cylinder position determining means includes a plurality of resistors having a predetermined resistance value, and forms a resistance ladder circuit with the engine control device. The own cylinder position is determined from the voltage at the predetermined position detected by the ladder circuit and the voltage difference.

  According to the third invention, when a resistance ladder circuit is formed by the resistor provided in the cylinder position determining means, the farther the cylinder position is away from the engine control device, the more the resistor connected to the resistance ladder circuit. As the number increases, the voltage detected at the predetermined position and the voltage difference become smaller as the cylinder position moves away from the engine control device.

  Therefore, it is possible to determine the position of the cylinder from the detected voltage and the voltage difference, and the diesel combustion engine having a plurality of cylinders can be made without increasing the number of ports of the engine control device and complicated wiring. The individual glow plug energization control device that controls the energization of the glow plugs provided for each cylinder enables the energization control and self-diagnosis for each cylinder.

  In a fourth aspect of the invention, the glow plug energization control device includes mode switching means for switching between a cylinder position determination mode for determining its own cylinder position and a drive mode for performing energization control for the glow plug. ).

  As in the fourth aspect of the present invention, the cylinder position determination mode and the drive mode can be switched by the mode switching means, so that the current cylinder position can be specified before the glow plug is energized. Can be used when the energization of the glow plug is started by switching the result to the drive mode.

  In addition, since the cylinder position determination mode and the drive mode can be switched by the switching means, it is not necessary to increase the number of ports of the engine control device in order to determine its own cylinder position.

  More specifically, as in the fifth invention, a drive command signal line for transmitting the drive command signal from the engine control device to the glow plug energization control device, and the glow plug energization control device to the engine control device. A plurality of glow plug energization control devices are connected via one input port and one output port of the engine control device using a self-diagnosis signal line for transmitting a self-diagnosis signal to the mode switching means; In the cylinder position determination mode, the resistance ladder circuit is formed via the drive command signal line and the self-diagnosis signal line.

  According to the fifth aspect of the present invention, the engine control device and the plurality of glow plug energization control devices are connected using the drive command signal line and the self-diagnosis signal line to determine the cylinder position of itself. Therefore, a resistor ladder circuit can be formed without increasing the number of ports of the engine control device, and the glow plug energization control device provided individually for each glow plug can recognize its own cylinder position.

  In the sixth invention, in the interface of the engine control device that transmits the drive command signal and receives the self-diagnosis signal, the drive command signal line is grounded on the engine control device side, and the self-diagnosis signal line Is raised to the power supply voltage on the engine control device side (claim 6).

  According to the sixth aspect of the invention, it is not necessary to provide a new port for grounding the glow plug energization control device when forming a resistance ladder circuit for determining the cylinder position. The voltage between the power supply voltage for stably receiving the self-diagnosis signal and the ground of the engine control device can be divided by the resistance ladder circuit to determine the cylinder position of each glow plug energization control device. .

  Further, on / off of the drive command signal transmitted from the engine control device can be used for switching in the detection result from the voltage detection means and switching in the detection result from the voltage difference detection means.

  More specifically, as in the seventh invention, the cylinder position determination means is disposed inside each glow plug energization control device between the engine control device and each glow plug energization control device in the cylinder position determination mode. When one of the plurality of resistors provided is connected in series and the other is connected in parallel, the voltage detected by the resistors connected in parallel and the voltage difference across the resistors connected in series The self-cylinder position is determined from the above (claim 7).

  According to the seventh aspect of the present invention, a glow plug energization control device that can determine its own cylinder position can be realized.

  In the eighth invention, the switching means provided between the glow plug provided for each cylinder of the diesel combustion engine and the power source is opened and closed based on the drive command signal transmitted from the engine control device that controls the operation of the engine. A control method of a glow plug energization control system that drives and controls energization to the glow plug, comprising a plurality of glow plug energization control devices that individually control energization to the glow plug, The plug energization control device includes at least a control unit that controls opening / closing of the switching unit based on the drive command signal, a cylinder position determination unit that determines its own cylinder position, and a self-diagnosis signal that detects abnormality of the glow plug. A self-diagnostic unit for transmitting the signal, and at least the mode switching means is determined prior to energization of the glow plug. Set mode comprises a cylinder position determination process determines the cylinder location provided with the above glow plug energization control apparatus (claim 8).

  According to the eighth aspect of the invention, since the cylinder position is confirmed before starting the energization of each glow plug, the same cylinder-by-cylinder operation as in the conventional one glow plug energization control device is performed. Energization control and failure diagnosis for each cylinder are possible.

  In a ninth aspect of the present invention, a drive mode switching step for setting the mode switching means to a drive mode is provided after the cylinder position is specified by the cylinder position determination step, and energization control for the glow plug is started. Sometimes, the drive command signal is set to a predetermined frequency in the drive mode, and when an abnormality of the glow plug and the glow plug energization control device is detected in the drive mode, the individual cylinder that sets the mode switching means to the individual cylinder failure determination mode A failure determination mode switching process is provided, the drive command signal is set to a predetermined frequency in the individual cylinder failure determination mode, and is transmitted at a duty ratio that can be received only by a glow plug energization control device in which an abnormality has been detected. 9).

  According to the ninth aspect, when an abnormality occurs in the glow plug energization control device provided for each glow plug, the failure state of the glow plug energization control device in which an abnormality has occurred can be determined in more detail. It becomes possible.

  In a tenth aspect of the invention, a self-diagnosis signal synchronization mode is provided to synchronize the output of a self-diagnosis signal output from the glow plug energization control device provided in each cylinder.

  According to the tenth aspect of the present invention, it is possible to prevent misrecognition on the side of the engine control device due to a shift in output timing of the self-diagnosis signal transmitted from the glow plug energization control device shell provided in each cylinder, and a highly reliable abnormality Detection can be performed.

The block diagram which shows the whole outline | summary of the glow plug energization control system in the 1st Embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS The outline | summary of each part which comprises the glow plug electricity supply control apparatus in the 1st Embodiment of this invention is shown, (a) is a circuit diagram which shows the outline | summary of the control part in drive mode, (b) is the cylinder determination in determination mode The circuit diagram which shows the outline | summary of a means, (c) is the circuit diagram which shows the outline | summary of the abnormality diagnosis part in drive mode The circuit diagram which shows the structure which enables the mode switching of the glow plug electricity supply control apparatus in the 1st Embodiment of this invention The flowchart which shows the cylinder determination method used for the glow plug energization control system in the 1st Embodiment of this invention. The cylinder position determination method of the glow plug energization control system in the 1st Embodiment of this invention is shown, (a) is an equivalent circuit schematic, (b) is an output waveform diagram which shows the relationship with a threshold value FIG. 5A is a characteristic diagram showing a relationship between a cylinder position and a voltage for determining a threshold value used in a determination mode of the glow plug energization control system according to the first embodiment of the present invention, and FIG. (C) is a map for specifying the total number of cylinders from the relationship between the voltage difference and the voltage. The flowchart which shows the abnormality determination method at the time of the drive used for the glow plug energization control system in the 1st Embodiment of this invention. The flowchart following FIG. The equivalent circuit diagram at the time of the drive of the glow plug electricity supply control apparatus in the 1st Embodiment of this invention. (A) is a time chart which shows the self-diagnosis signal at the time of normal in drive mode, (b) is a time chart which shows an example of the self-diagnosis signal at the time of normal in drive mode. The time chart which shows an example of the failure diagnosis result in individual failure determination mode. The block diagram which shows the whole outline | summary of the glow plug electricity supply control system in the 2nd Embodiment of this invention. The block diagram which shows the whole outline | summary of the glow plug electricity supply control system in the 3rd Embodiment of this invention. The block diagram which shows the cylinder position discrimination method in embodiment of FIG. The block diagram which shows the whole outline | summary of the glow plug energization control system in the 4th Embodiment of this invention. The block diagram which shows the cylinder position discrimination method in embodiment of FIG. (A) is a time chart which shows the self-diagnosis signal at the time of normality, (b) is a time chart which shows an example of the self-diagnosis signal at the time of abnormality occurrence. The time chart which shows the switching method between drive mode and self-diagnosis signal synchronous mode.

With reference to FIG. 1, the outline | summary of the glow plug electricity supply control system 1 in the 1st Embodiment of this invention is demonstrated.
The glow plug energization control system 1 according to the present invention energizes each glow plug energization to a glow plug 10 _{(1 to n)} provided for each cylinder of a diesel combustion engine 2 having a plurality of (n cylinders) cylinders which are not described in detail. Control is individually performed by the control unit (GCU) 100 ₍ 1 to _n) .

The engine control unit (ECU) 3 calculates a drive command signal SI corresponding to the driving situation based on information from the driving situation detection means 4 that detects the driving situation of the engine 2 and passes through the drive command signal line WIR _SI . thereby to send to each _{GCU100 (1~n),} receiving the self-diagnosis signal DI via the self-diagnosis signal line _{WIR DI} sent from the _{GCU100 (1~n).}

In the present embodiment, one output port _{P SI} and a plurality of _GCU100 provided in the interface I / F30 in ECU3 and ₍₁₎ ~100 _(n) is directly connected via a drive command signal lines _{WIR SI} One the closest GCU100 (1) and is connected to the input port _{P DI} and ECU 3, yet another _{GCU100 (2~n),} each _{GCU100 (2~n} with self-diagnosis signal line _{WIR DI} from GCU100 ₍₁₎ output port _P DI _in) are connected in a daisy chain sequentially via respective _{P DI0.}

Each GCU 100 _(1-n) includes a drive control unit (DCU) 110 _(1-n) , a cylinder position determination means (IDU) 120 _(1-n) , and a self-diagnosis unit (DIU) 130 _{(1-n), respectively.} And a control unit (PRG) 140 _{(1 to n)} that controls these logic or programs.
Based on the drive command signal SI, the DCU 110 _{(1 to n)} controls the energization of each glow plug 10 _{(1 to n)} by controlling the opening and closing of the switching means 116 by a control method described later.
The IDU 120 determines the cylinder position where each GCU 100 _{(1 to n)} is provided by a cylinder position determination method described later.
The DIU 130 detects an abnormality occurring in each of the glow plugs 10 _{(1 to n)} and the GCU 100 _{(1 to n)} by a determination method described later, and transmits a self-diagnosis signal DI.

Referring to FIG. 2, _DCU110 constituting _{GCU100 (1~n)} in this embodiment _{(1~n), IDU120 (1~n)} , will be described in more specific example configuration of _{DIU130 (1~n).}
In the present invention, the GCU 100 is switched by switching predetermined switches (112, 121, 126, 131) provided as mode switching means between the cylinder determination mode for determining the cylinder position and the drive mode for performing normal drive control. _{(1 to n)} , each unit DCU110 _{(1 to n)} , IDU 120 _{(1 to n)} , DIU 130 _{(1 to n)} is changed to change the mode and is characterized in that first, The structure of each part DCU110 _(1-n) , IDU120 _(1-n) , DIU130 _(1-n) in mode is demonstrated.

As shown in FIG. 2A, the DCUs 110 _{(1 to n)} in the drive mode include a pull-up resistor 111, a first drive mode switch 112, a comparator 113, a constant voltage power supply 115, a pulse adjustment logic 114, and a switching element 116. It is comprised by the driver containing.
The I / F 30 of the ECU 3 is provided with a transistor 301 that is grounded on the ECU 3 side. The drive command signal line WIR _SI that connects the ECU 3 and the GCU 100 _{(1 to n)} and transmits the drive command signal _SI is in the drive mode. Since the first drive mode switch 112 is closed, the GCU 100 _{(1 to n)} side is pulled up to the battery voltage + B supplied as the power supply voltage via the switch SW 112 and the pull-up resistor 111. .

Constant voltage power supply 115 is given a reference potential _{V SD} obtained by dividing the battery voltage + B min comparator 113.
The comparator 113, the battery voltage is opened and closed in response to a drive command signal SI + B and the reference potential V _SD is input by these comparisons are affected by voltage fluctuations so HI, LO is switched output voltage The drive command signal SI is reliably transmitted to the GCU 100 _(1-n) side without any problem.

The pulse adjustment logic 114 converts the output voltage of the comparator 113 into an individual drive command signal corresponding to a cylinder position specified by a cylinder determination method described later.
In response to the drive command signal transmitted from the pulse adjustment logic 114, the switching element 116 provided in the driver is opened and closed to control energization and stop of the drive voltage BATT, and power is supplied to the glow plug 10 at a predetermined duty ratio.
As the switching element 116, a semiconductor power device such as a MOSFET or an IGBT is used.

Input port of each _{DCU110 (1~n)} are respectively connected to one output port _{P SI} of ECU3 by the connected drive command signal lines _{WIR SI} to distribute to each _{DCU110 (1~n),} each is transmitted to the drive command signal SI directly to DCU _{(1 to n),} by the pulse adjustment logic 114 provided in respective _{DCU110 (1~n),} adjustment of the phase corresponding to the cylinders position is achieved.
For example, with respect to the drive command signal SI input simultaneously _to each DCU _{(1 to n)} , the pulse adjustment logic 114 delays one cycle at a time in the cylinder order according to the recognized cylinder position, or 1/4 It can be delayed by a cycle.

As shown in FIG. 2B, in the cylinder determination mode, the IDU 120 ₍ 1 to _n) includes the first determination mode switch 121, the voltage difference detection resistor 122, the second determination mode switch 126, and the voltage difference detection. The circuit includes a means 124, a voltage detection resistor 127, a voltage detection means 123, and a cylinder determination logic 125.
In the cylinder determination mode, the first determination mode switch 121 and the second determination mode switch 126 are closed, and the battery voltage + B and the ground of the ECU 3 are connected to the pull-up resistor 302, the self-diagnosis signal lines WIR _ID and IDU 120. _{(1 to n)} , the drive command signal line WI _SI , and the transistor 301 are connected.

The voltage difference detecting means 124 has, as a predetermined position, a voltage difference ΔV _{(1 to n)} between both ends of a voltage difference detecting resistor 122 (resistance value R ₁₂₂ Ω) connected between the DI terminal and the DI0 terminal of the GCU 100. The voltage detection means 123 detects the voltage difference between the battery voltage + B by the pull-up resistor 302 (resistance value R ₃₀₂ Ω) and the voltage detection resistor 127 (resistance value R ₁₂₂ Ω). The voltage V _{(1 to n)} input to the DI terminal of the GCU 100 is detected as a predetermined position upstream of the device 122 (resistance value R ₁₂₂ Ω).
The cylinder position determination means 125 determines the position of the cylinder from the detected voltage difference ΔV _{(1 to n)} and the voltage V _{(1 to n),} and outputs the result as a self-diagnosis signal DI. In the above-mentioned drive mode, it is used for transmitting individual drive command signals.

A plurality of IDUs 120 _{(1 to n)} provided in each GCU 100 _{(1 to n)} are connected _to one input port and one output port of the engine control device via the drive command signal line WIR _SI and the self-diagnosis signal line WIR _ID. Since the number of the voltage difference detection resistor 122 and the voltage detection resistor 127 to be connected differs depending on the position of the cylinder, the voltage difference detection unit 124 and the voltage detection unit 123 detect the voltage difference. The position of each cylinder can be determined from the voltage difference ΔV _{(1 to n)} and the voltage V _{(1 to n)} .
In the cylinder determination mode, the voltage detection resistor 127 is provided in parallel _to each GCU 100 _{(1 to n)} , and the voltage difference detection resistor 122 is provided to each GCU 100 (1 to n). The cylinders are provided in series in the order of cylinders.

As shown in FIG. 2C, the DIU 130 _{(1 to n)} in the drive mode includes the second drive mode switch 131, the plug current detection / plug voltage detection circuit 132, the abnormality determination means 135, and the switching means (MOSFET) 136. It is constituted by.
As the plug current detection / plug voltage detection circuit 132 of each DIU 130 _{(1 to n)} , known plug current detection and plug voltage detection circuits can be appropriately employed.
The plug current detection circuit, the plug current IGL detected by the plug voltage detection circuit, and the plug voltage VGL are used for driving assistance and abnormality diagnosis of GCU (1 to n).
Abnormality determining means 135, and a plug current _{I GL} and the plug voltage _{V GL,} breakage, degradation, to determine the presence or absence of an abnormality of the glow plugs _{(1 to n)} and _{GCU100 (1~n)} such as short circuit, as a result Is transmitted as a self-diagnosis signal ID.

The drain of the switching means 136 is pulled up to the battery voltage + B on the ECU 3 side through the self-diagnosis signal line WIR _ID and the pull-up resistor 302, and the source of the switching means 136 is grounded on the GCU100 _(1-n) side Has been.
The output of the abnormality determining means 135 is connected to the gate of the switching means 136, the switching means 136 is opened / closed according to the level of the self-diagnosis signal ID, and transmitted to the ECU 3 side through the self-diagnosis signal line WIR _DI .
In the drive mode, since the second drive mode switch 131 is closed, a plurality of IDUs 130 provided in each glow plug 10 _(1-n) are connected in parallel to the ECU 3 via the I / F 30. It becomes.

With reference to FIG. 3, a configuration example that enables switching between the determination mode and the drive mode of the glow plug energization control system 1 in the present embodiment will be described.
In the present invention, the ECU 3 and the GCU 100 _{(1 )} are switched by switching between a determination mode in which each GCU 100 _{(1 to n)} determines its position and a drive mode for controlling energization to the glow plug 1 ₍ 1 to _n) . a drive command signal lines WIR _SI and self-diagnosis signal line WIR _ID connecting the _~n), the determination mode, used to form the dividing resistor ladder circuit for identifying the cylinder position, the drive mode, the drive command signal lines The WIR _SI and the self-diagnosis signal line WIR _ID are used for transmission of the drive command signal SI and transmission of the self-diagnosis signal DI, which are their original uses.

As shown in FIG. 3, the drive command signal line WIR _SI includes a drive mode switch 112 for connecting the drive command signal line WIR _SI and the battery voltage via a pull-up pull-up resistor 111 in the drive mode, and a determination. In the mode, a first determination mode switch 126 for connecting the drive command signal line WIRSI and the self-diagnosis signal WIR _DI via the divided voltage detection resistor 127 is connected.
The first drive switch 112 and the first determination mode switch 126 operate exclusively with each other, and are configured such that when one is closed, the other is opened.

In addition, the self-diagnosis signal line _{WIR DI,} in the drive mode, the second driving mode switch 131 for short-circuiting the DI pin and DI0 terminal _{GCU100 (1~n),} the determination mode _GCU100 of _{(1 to n)} A second determination mode switch 121 for interposing a voltage difference detecting resistor 122 is connected between the DI terminal and the DI0 terminal.
The second determination mode switch 121 and the second drive mode switch 131 are configured to operate exclusively with each other, and when one is closed, the other is opened. As shown in the present embodiment, each may be configured by another switch, or may be configured to be switched alternatively by one switch.
In addition, in this embodiment, since each GCU100 _(1-n) may have the completely same structure, it has abbreviate _| omitted and described the internal structure of GCU100 _(2-n) in this figure.

In the determination mode, the first determination mode switch 126 and the second determination mode switch 121 are closed, the first drive mode switch 112 and the second drive mode switch 131 are opened, and the IDU 120 _{( 1-n)} are formed.
In the drive mode, the first determination mode switch 126 and the second determination mode switch 121 are opened, and the first drive mode switch 112 and the second drive mode switch 131 are closed. DCU 110 _(1-n) and DIU 130 _(1-n) are formed.

A cylinder position determination method used in the glow plug energization control system 1 according to the first embodiment of the present invention will be described with reference to FIG.
Note that a program or logic for carrying out this determination method is stored in each of the PRGs 140 ₍ 1 to _n) shown in FIG. 1 and executed independently in each glow plug 100 ₍ 1 to _n) .
When a key switch (not shown) is turned on to start operation of the diesel combustion engine 2, a cylinder to be controlled by each GCU 100 _{(1 to n)} according to the flowchart shown in FIG. The position determination is started.

In the determination mode setting process of step S100, the first determination mode switch 126 is set to set the GCU 100 _{(1 to n)} to the determination mode in order to determine its own cylinder position prior to the start of energization to the glow plug 10. The second determination mode switch 126 is closed, and the first drive mode switch 112 and the second drive mode switch are opened.
Next, in the voltage detection process in step S110, the voltage detection means 123 monitors the absolute value of the voltage V ₍ 1 to _{n) at} the DI terminal of each blow plug 100 ₍ 1 to _n) .

Subsequently, in the voltage difference detection process in step S120, the voltage difference detection means 124 monitors the voltage difference ΔV _{(1 to n)} across the voltage difference detection resistor 122.
Next, in the cylinder number N determination step in step S130, the detected voltage V _{(1 to n)} and the voltage difference ΔV _{(1 to n)} are compared with threshold values such as map data provided in the cylinder determination means 125, and diesel combustion is performed. The total number of cylinders N of the engine 2 is determined.

Depending on the number of cylinders n, in the determination mode, the number of voltage difference detection resistors 122 and voltage detection resistors 127 connected to the IDU 120 _{(1 to n)} increases, and each voltage difference detection resistor 122 _{(1 to n) ) And the} voltage detection resistor 127 _{(1 to n)} are reduced, and the voltage V _{(1 to n)} and the voltage difference ΔV _{(1 to n)} detected in each IDU 120 are reduced.
By comparing this with a threshold value such as map data prepared in advance, the total number of cylinders N of the combustion engine 2 can be determined.

If some abnormality occurs in the voltage difference detection in the cylinder number N determination step in step S130 and the total number of cylinders N cannot be specified, the determination is No, and the process returns to step S110 to determine the cylinder number N again.
If the identification of the total number N of cylinders is completed, the determination becomes Yes, and the process proceeds to the self-cylinder determination row in steps S140 to S170.

In the self-cylinder determination process in step S140, the detected voltage value V _(1-n) is compared with the voltage threshold value ( _{VREF (N) L-} VREF _{(N) H} ) for the Nth cylinder. judge.
For example, if the voltage value V _{(1 to n)} is larger than the voltage threshold value V _{REF (N) L and} smaller than V _{REF (N) H} in the case of the Nth cylinder, it is specified that the own cylinder is the Nth cylinder. The determination is Yes, the determination ends, the voltage value V _{(1 to n)} is equal to or lower than the voltage threshold V _{REF (N) L} , and if the position of the self-cylinder is not specified, the determination is No and Step S150 is performed. Then, the threshold value is determined by comparison with the threshold values (V _{REF (N−1) L to} V _{REF (N−1) H} ) for the _N− 1th cylinder.

If it is determined that the self-cylinder is the N-1th cylinder, the determination is Yes. If the determination is completed and the position of the self-cylinder is not specified, the determination is No, and the process proceeds to step S160. The threshold value is determined by comparison with threshold values (V _{REF (N−2) L to} V _{REF (N−2) H} ). The threshold value determination is repeated while reducing the position of the cylinder to be compared. By comparing the threshold value (V _{REF2L to} V _REF2H ) in the case of the second cylinder with the voltage value V _{(1 to n),} it is determined whether the self cylinder is the second cylinder. If the cylinder number is specified, all determinations are completed.
In addition, since the DI ₀ terminal of the Nth cylinder is OPEN, no voltage difference occurs between both ends of the voltage difference detection resistor 122, and ΔV _(n) = 0v, so that it is immediately the Nth cylinder. Can be determined.

With reference to FIG. 5, a specific cylinder determination method in the present embodiment will be described by taking the case of four cylinders as an example.
As shown in FIG. 5A, in the determination mode, the battery voltage + B connected through the pull-up resistor 302 of the I / F 30 provided on the ECU 3 side and the transistor 301 of the I / F 30 provided on the ECU 3 side are connected. The voltage difference detection resistor 122 and the voltage detection resistor 127 provided in the GCU 100 ₍₁ to ₄₎ are connected to the ground connected via the GCU 100 ₍₁ to _4), and the voltage provided to each GCU ₍₁ to _4). detecting means 123, voltage V and the voltage difference [Delta] V detected by the voltage difference detection means 124, by the respective cylinder _positions, V 1 ~V _4, changes ΔV ₁ ~ΔV _4.

When the drive command signal SI is transmitted from the ECU 3 and the transistor 301 of the ECU 3 is opened and closed, the voltages V _{(1 to n)} detected by the GCUs 100 _{(1 to n)} are changed to cylinders as shown in FIG. Varies with position.
As a specific example of the voltage threshold voltage V _{REF (1 to n)} , for example, the battery voltage + B is 12 v, the resistance value R ₃₀₂ of the pull-up resistor ₃₀₂ is 1 kΩ, and the resistance value R _{122 of the} voltage difference detection resistor _{122 is used.} Is 10 kΩ and the resistance value R _{127 of} the voltage detection resistor ₁₂₇ is 1 kΩ, and when a threshold value of ± 5% is set, V _{REF (1)} = 8.7-9. 6v is given as a threshold, V _{REF (2)} = 6.9 to 7.6v is given as a threshold for the second cylinder, and V _{REF (3)} = 5. 8 to 6.4 v is given as a threshold value, and ΔV = 0 or V _{REF (4)} = 4.8 to 6.4 v is given to the fourth cylinder.
For example, in the case of GCU100 ₍₃₎ provided in the third cylinder, if 6.11v is detected by the voltage detection means 123, since it is 6.11v> 4.7 to 5.4v in step S140, the determination No. Thus, the process proceeds to step S150. Since 5.8v <6.11v <6.4v in step S150, the determination is Yes, and the third cylinder is specified.

With reference to FIG. 6, a threshold value for determining the maximum number of cylinders N used in the cylinder position determination mode and a threshold value determination method for determining the cylinder position will be described.
As shown in FIG. 6A, the voltage V _{(1 to n) at} the DI terminal of each GCU 100 _{(1 to n)} detected by the voltage detecting means 123 is larger as the total number of cylinders N is larger, and the cylinder position And the number of voltage difference detecting resistors 122 connected in series with the number of voltage detecting resistors 127 connected in parallel between the plurality of GCUs between the battery voltage + B and the ground as the distance from the ECU 3 increases. Increases and the voltage V _{(1 to n)} decreases, and as shown in FIG. 5B, the voltage difference ΔV _{(1 to n)} between the DI terminal and the DI ₀ terminal detected by the voltage difference detecting means 124. Also goes down.
As shown in FIG. 5C, if the relationship between the voltage difference ΔV _{(1 to n)} and the voltage V _{(1 to n)} is _converted into map data in advance, the arbitrary voltage difference ΔV _(i) and the voltage V _{( The} total number of cylinders N can be determined for _i) .

With reference to FIGS. 7 and 8, switching to the drive mode used in the glow plug energization control system 1 in the first embodiment of the present invention, an abnormality detection method in the drive mode, and an individual cylinder failure at the time of abnormality detection An individual failure determination method in the determination mode will be described.
In the present embodiment, a case of four cylinders will be described as an example.

When the key switch is turned on in the starting process of step S200, a voltage is supplied to each GCU 100 _(1-n), and the cylinder position determination process of steps S110 to S170 is performed through the determination mode switching process of step S100 described above. Is started, the total number of cylinders N is determined, and the cylinder position of each GCU 100 _{(1-n) is} further determined.
When the cylinder position is determined, the first determination mode switch 122 and the second determination mode switch 126 are opened in the drive mode switching process of step S210, and the first drive mode switch 112 and the second drive mode switch are opened. 131 is closed.

Next, in the glow plug energization process in step S220, energization to the glow plug 10 is started.
At this time, the drive command signal SI calculated in the ECU 3 is transmitted as a pulse signal with a frequency of 30 Hz, and is provided in each GUC 100 _{(1 to n)} with a predetermined duty ratio calculated according to the operating state of the engine 2. Each switching element 116 is driven to open and close at the timing adjusted by the pulse adjusting means 114.

In the failure determination process during energization in step S230, each glow plug is detected by the plug current detection means 132 and the plug current detection circuit 133 provided in each GCU 100 _{(1 to n)} while the glow plug 10 _{(1 to n)} is energized. 100 plug current IGL flowing through _{(1 to n)} is detected, the plug voltage _{V GL} which is applied to the glow plug by the plug voltage detecting circuit 134 provided in each _{GCU100 (1~n)} is detected, the plug current _{I GL} And the plug voltage V _GL , the abnormality determining means 135 determines whether or not the glow plugs 10 _{(1 to n)} and the GCU 100 _{(1 to n)} always have a failure during energization.
At this time, it is determined whether every cylinder is normal or abnormal every five cycles, and the self-diagnosis signal DI is output.

If there is no failure in step S230, it is determined that there is no failure, a self-diagnosis signal DI indicating normality is transmitted, the process proceeds to the energization operation continuing step of step S240, and the normal energization operation is continued. At this time, a normal mode output is made as a diagnosis signal.
If a failure is detected in step S230, it is determined that there is a failure, and the process proceeds to a failure diagnosis signal output process in step S250. At this time, an abnormal mode output is made as a diagnosis signal.

In the failure diagnosis signal output process in step S250, a failure diagnosis signal (diag) DI is output from each GCU 110 _(1-n) and transmitted to the ECU 3.
In the ECU cylinder determination process of step S260, the ECU 3 side identifies the cylinder that has failed by reading DI output DI, and sets the failure flag. If the failure cylinder is successfully identified, the determination is Yes. It progresses to the energization operation stop process of step S270.

In the ECU cylinder determination process in step S250, if the failed cylinder cannot be identified due to a DI reading error or the like, the determination is No, the process returns to step S230, and the failure determination is repeated.
In the energization operation stop process in step S270, energization to the glow plugs determined to be internal failures of the respective glow plugs 10 _{(1 to 4)} is stopped.

Next, in the individual cylinder failure determination mode switching process in step S280, the transmission period of the drive command signal SI from the ECU 3 is changed from the drive mode period T _DRV (for example, 30 Hz) in the drive mode to the individual determination mode period T _JDG in the individual determination mode. (For example, 60 Hz).
For transmitting a drive command signal SI only occurring in the _{GCU100 (1-4)} of the failure, cylinder failure glow plug _{10 (1-4)} or _{GCU100 (1-4)} has occurred cylinder # 1 .About. # 4, in the case of the first cylinder, it is output at a 20% duty of the drive command signal SI as shown in step S290, and in the case of the second cylinder, the drive command signal SI is shown as shown in step S300. In the case of the third cylinder, it is output at the 60% duty of the drive command signal SI as shown in step S310. In the case of the fourth cylinder, the drive command is given as shown in step S320. Output with 80% duty of signal SI.

In the individual self-diagnosis signal DI output process in step S330, each GCU 100 _(1-4) receives only the drive command signal SI having a duty ratio corresponding to its own cylinder position, and diagnoses the details of the abnormality.
At this time, there is no response except for the target GCU, and the GCU 100 _{(1 to n)} that has received the drive command signal SI having a predetermined duty ratio outputs a self-diagnosis signal DI indicating an individual failure mode.

With reference to FIG. 9, the structure of GCU100 _(1-n) in the drive mode of the glow plug energization control system 1 in the first embodiment will be described.
Note that the internal configurations of the respective GCUs 100 _{(1 to n)} are all common, and therefore the internal configuration is omitted except for the GCU 100 ₍₁₎ .

As shown in FIG. 9, in the drive mode, the first drive mode switch 112 and the second drive mode switch 131 are closed.
The drive command signal line WIR _SI connected to the transistor 301 grounded on the ECU 3 side is pulled up to the battery voltage + B via the pull-up resistor 111 on each GCU 100 _{(1 to n)} side.

The input level of the comparator 113 is switched in accordance with the drive command signal SI transmitted from the ECU 3, and the influence of voltage fluctuation or the like is eliminated by comparison with the reference potential input to the comparator 113, and stable binary output of Hi and Lo. And output from the comparator 113.
The pulse adjustment logic 114 converts the output voltage of the comparator 113 into individual energization signals G _{(1 to n)} corresponding to the cylinder positions specified in the above-described cylinder determination mode, and drives the switching element 116 to open and close.

When the switching element 116 is opened and closed, the drive voltage BATT input to the switching element 116 is supplied to the glow plug 10 at a predetermined duty ratio corresponding to the drive command signal SI calculated by the ECU 3.
On the other hand, the DI terminal and DI ₀ terminal of each GUC 100 _{(1 to n)} are connected to one input port P _DI of the ECU 3 via the self-diagnosis signal line WIR _ID , and further via the pull-up resistor 302 on the ECU 3 side. The battery voltage + B is pulled up, and the DI terminal and DI ₀ terminal of each GCU100 _{(1 to n)} are connected in order.

Between the glow plug 10 and the switching element 116, current detecting unit 132 is provided, the current by the detection means 133 and the voltage detecting means 134, detecting a plug current _{I GL} and the plug voltage _{V GL} flowing through the glow plug 10 during driving and, the abnormality determining means 135, excessive temperature rise of the glow plug _{10 (1 to n)} of each _{GCU100 (1~n)} to control, deterioration, abnormality such as disconnection and, each _{GCU100 (1~n)} and glow plug Abnormalities such as overcurrent, short circuit, and disconnection that occur during the period are detected.
In the present embodiment, the self-diagnosis signal DI transmitted from each of the GCUs 100 _{(1 to n)} provided for each cylinder of the engine 2 is connected to the power supply voltage + B via the pull-up resistor 302 to form a wired OR circuit. Are connected to each other. In accordance with the cylinders recognized by the cylinder position determination means IDU120 _{(1 to n)} , the output bits of the respective self-diagnosis signals are changed and output, and the engine control device 3 is used as a group of data frames synthesized by the wired OR circuit. Call to.

When an abnormality is detected by the abnormality determination means 135, a self-diagnosis signal DI is transmitted, the MOSFET 136 is driven to open and close, and is transmitted to the ECU 3 side as binary serial data.
As described above, in the drive mode, each of the self-diagnosis signal ID is closing drive command signal SI, which is adjusted by the pulse adjustment logic 114 provided in respective _{GCU100 (1~n)} of each _{GCU100 (1~n)} It is transmitted in accordance with the timing, and it is united by one self-diagnosis signal line WIR _DI and transmitted to the ECU 3 side.

The transmission of the self-diagnosis DI from each GCU 100 _{(1 to n)} is synchronized with the drive command signal SI, and can be delayed at a predetermined reading timing with respect to the rise of the drive command signal SI.
As described above, when it is determined that there is a failure, the ECU 3 stops the energization operation and switches the transmission cycle of the drive command signal SI to the individual cylinder failure determination mode.

The ECU 3 transmits a drive command signal SI having a duty ratio that matches the position of the cylinder where the failure has occurred with an individual determination mode cycle T _JDG (for example, 60 Hz).
Each GCU 100 _{(1 to n)} receives only the drive command signal SI to be received by the difference in the duty ratio, performs a detailed failure diagnosis, and sends only the cylinder in which the failure has occurred to the self-diagnosis signal DI. To do.
The difference in duty ratio can be recognized by detecting the period and duty with the SI input circuit and can be determined with a known internal logic circuit.

A specific example of the self-diagnosis signal transmitted in the drive mode in the case of four cylinders will be described with reference to FIG.
Since the self-diagnosis signals DI transmitted from each GCU 100 _(1-4) are connected in parallel, as shown in FIG. 5 (a), it is confirmed that each GCU 100 _(1-4) is normal. The output shown rises in order, but since they are output shifted by one cycle, they cancel each other out, and in the ECU 3, all the data bits become Lo to indicate that the first to fourth cylinders are normal, In synchronization with the fall of the self-diagnosis signal DI from the GCU 100 ₍₄₎ , the self-diagnosis signal DI indicating the end of the determination and having the data bit set to Hi is transmitted.

On the other hand, for example, when there is a failure in the second cylinder, as shown in this figure (b), a self-diagnosis signal indicating that only the second cylinder of each GCU100 _(1-4) is normal does not rise. The self-diagnosis signal DI transmitted to the ECU 3 rises in synchronization with the fall of the self-diagnosis signal of the first cylinder, and the second cylinder that rises in synchronization with the rise of the self-diagnosis signal of the third cylinder is abnormal. The data bit indicating HI becomes Hi, and in synchronization with the falling of the self-diagnosis signal of the fourth cylinder, the self-diagnosis signal DI having the data bit HI indicating the end of determination is transmitted.

With reference to FIG. 11, a specific example of the determination result in the individual cylinder determination mode when any failure is detected as described above will be described.
In the individual determination mode, as shown in FIG. 5A, the drive command signal SI of the individual determination mode with the duty ratio corresponding to the GCU 100 ₍₁ to ₄₎ in which the failure is detected is the individual determination mode cycle T _JDG and the ECU 3 Called from.
In each GCU 100 _{(1 to 4)} , the duty ratio of the drive command signal SI that can be received in the individual determination mode is set based on the cylinder position determined by the cylinder position determination described above. For example, in the case of four cylinders, the first cylinder can receive a drive command signal with 20% duty, the second cylinder with 40% duty, the third cylinder with 60% duty, and the fourth cylinder with 80% duty. .
As shown in this figure (b), the GCU100 ₍₂₎ performs an abnormality diagnosis on the drive command signal transmitted at 40% duty, 60 Hz, and outputs a self-diagnosis signal DI corresponding to a predetermined failure mode. Since the normal GCU 100 _{(1, 3, 4)} does not receive the 40-duty drive command signal, the self-diagnosis signal is not output for all periods, and the GCU 100 ₍₂₎ self-diagnosis as a whole A signal obtained by inverting the signal is transmitted to the ECU 3.

A glow plug energization control system 1a according to the second embodiment of the present invention will be described with reference to FIG.
In the above embodiment, the glow plug energization control device 1 in which the glow plug 10 and the GCU 100 are integrally provided as shown in FIG. 1 has been described. However, as shown in FIG. 12, each GCU 100 _(1-n) May be separated from each glow plug 10 and placed in the vicinity thereof, and each GCU 100 _{(1 to n)} and each glow plug 10 may be connected to each other via a conduction line WIRGL. Also in this embodiment, the same effect as the above embodiment is exhibited.

A glow plug energization control system 1b according to a third embodiment of the present invention will be described with reference to FIGS.
In the above embodiment, as the cylinder one determining means 120, the voltage difference detecting resistor 122 and the voltage detecting resistor 127 are provided in the GCU 100, and a resistance ladder circuit is formed between the ECU 3 and the cylinder position. Although the configuration of recognizing its own cylinder position from the value of the combined resistance that changes in accordance with the value is shown, the cylinder position is set on the communication wiring path (harness WIR _SI ) for transmitting the drive command signal SI as in this embodiment. It is good also as a structure which provided the resistance 122b _(1-n) for cylinder discrimination | determination which has different resistance value _{R122 (1)} -R122 _{(n-1) according} to it.

According to the present embodiment, as shown in FIG. 14A, the Hi-side potential of the voltage ΔV when the drive command signal SI for the first cylinder is turned on is the pull-up resistor on the GCU 100b ₍₁₎ side. has been lifted to the supply voltage + B through a 111, the potential of the Lo side, the resistance value _{R 122 (1)} of the cylinder identification resistor 122b _(1), by the resistance _{R 111} of the pull-up resistor 111, a power supply voltage + B and a filter (capacitor) voltage V ₁ becomes the prorated voltage ΔV between 115a, as shown in the figure (b), the voltage ΔV when the second cylinder th drive command signal SI is turned on The potential on the Hi side is raised to the power supply voltage + B via the pull-up resistor 111 on the GCU 100b ₍₂₎ side, and the potential on the Lo side is the resistance value R _{122 (2 )} of the cylinder discrimination resistor 122b _{(2). a),} up By the resistance value _{R 111} of up resistor 111, the power supply voltage + B and the filter voltage potential _{V 2} becomes the prorated the between (capacitor) 115a, as shown in the figure (c), n cylinders th drive command The Hi side potential of the voltage ΔV when the signal SI is turned on is raised to the power supply voltage + B via the pull-up resistor 111 on the GCU 100b _(n) side, and the Lo side potential is the cylinder discrimination resistance. 122b _(n) and the resistance _{R 122} of the _(n), by the resistance _{R 111} of the pull-up resistor 111, a potential _{V n} of prorated voltage ΔV between the power supply voltage + B and a filter (capacitor) 115a .

At this time, in this embodiment, R _{122 (1)} <R _{122 (2)} <... <R _{122 (n)} or R _{122 (1)} > R _{122 (2)} >. Since it is set to be _{122 (n)} , when the cylinder discrimination resistance 112 _{(1 to n)} is gradually increased in order of the cylinder from the side closer to the engine control device, the drive command signal SI is turned on. In this case, the Lo-side potentials V ₁ , V ₂ ,... V _n gradually decrease, and conversely, the cylinder discrimination resistors 112 _{(1 to n)} are gradually decreased in order of cylinders from the side closer to the engine control device. In this case, the Lo-side potentials V ₁ , V ₂ ,... Vn of the drive command signal SI gradually increase.
Therefore, if the Lo-side potentials V ₁ , V ₂ ,... V _n of the drive command signal SI are determined as threshold _values , the cylinder position can be recognized.
In the present embodiment, the cylinder discrimination for the first cylinder 112 (1) may be omitted. In this case, the Lo-side potential V1 when the drive command signal SI is turned on is 0v.

A glow plug energization control system 1c according to a fourth embodiment of the present invention will be described with reference to FIGS.
In the third embodiment, the cylinder position is determined by _disposing a cylinder having the resistance value R _{122b (1 to n)} that gradually changes according to the cylinder position as the cylinder determining resistance 122b _{(1 to n).} In the present embodiment, on the drive signal harness WIR _SI provided as a communication wiring path for transmitting the drive command signal SI, and the own GCU 100c _{(1 to (n-1))} constant resistance value _{R 122c (1 to n)} for cylinder discrimination resistor ₁₂₂ having a _{c (1 to n)} is provided between the _GCU100c provided in the following cylinders _{(2- through n).}
Further, the cylinder discrimination resistor 122c _{(1 to n)} may be placed inside the connector that connects the harness WIR _SI and the GCU 100 _{c (1 to n)} .

With this configuration, as shown in FIG. 16A, the Hi side potential of the voltage ΔV when the drive command signal SI for the first cylinder is turned on is pulled on the GCU 100c ₍₁₎ side. has been lifted to the supply voltage + B through the up resistor 111, the potential V ₁ of the Lo side has a 0 v, as shown in the figure (b), 2 cylinders th drive command signal SI is turned on The potential on the Hi side of the voltage ΔV at this time is raised to the power supply voltage + B via the pull-up resistor 111 on the GCU 100c ₍₂₎ side, and the potential on the Lo side is the resistance of the cylinder discrimination resistor 122c ₍₂₎ . the value _{R 122 (1),} shown by the resistance _{R 111} of the pull-up resistor 111, the power supply voltage + B and a filter (capacitor) voltage potential _{V 2} becomes the prorated to between 115a, in the figure (c) N The Hi-side potential of the voltage ΔV when the tubular th drive command signal SI is turned on, and lifted to the supply voltage + B through a pull-up resistor 111 in GCU100cb _(n) side, the potential of the Lo side , n-1 pieces of cylinder identification resistor 122c are connected in series, and (n-1) times the resistance value of the resistance value _{R 122,} by the resistance value _{R 111} of the pull-up resistor 111, the power supply voltage + B and the filter A potential V _n is obtained by _dividing the voltage between the capacitor 115a and the capacitor 115a.

Therefore, as in the above embodiment, if the Lo-side potential is determined as a threshold when the drive command signal SI is turned on, its own cylinder position can be recognized.
In the above embodiment, as the known current detection and voltage detection circuit 132, a shunt resistor having a known resistance value is provided on the upstream side of the glow plug 10 as the current detection means, and the potentials at both ends thereof are measured. Then, the plug current I _GP is detected, the output voltage of the switching means 116 is detected as the plug voltage V _GP, and the presence or absence of abnormality such as disconnection is detected from the values of the plug current I _GP and the plug voltage V _GP. As shown in the present embodiment, a current mirror circuit may be configured by using a part of the transistor cells of the semiconductor switching element 135 as the current detection means 132 to detect the mirror current. By adopting such a configuration, it is possible to reduce the loss due to the shunt resistance.
In the present embodiment, as shown in FIG. 15, a drive power harness WIR _{+ B} for transmitting a power supply voltage + B, a drive signal harness WIR _SI, and a self-diagnosis signal harness WIR _ID are connected to a pair of connectors. In FIG. 1, the configuration in which the GCU 100 _{c (1 to n)} side is connected together is shown. The power line (drive power supply wiring WIR _{+ B} ) and the signal line (drive signal harness WIR _SI and self-diagnosis signal harness WIR _ID ) You may make it wire separately.

With reference to FIGS. 17 and 18, another embodiment of the self-diagnosis signal used in the glow plug energization control system of the present invention will be described.
FIG. 17A shows the data structure of the self-diagnosis DI which is synthesized by the DIU self-diagnosis signal DI (first cylinder to fourth cylinder) provided in each cylinder and the wired OR circuit and is input to the ECU at normal time. FIG. 17B is a time chart illustrating an example in which a disconnection abnormality occurs in the GCU 100 (2) of the second cylinder at the time of abnormality.

As shown in FIG. 17 (a), when the DIU 130 provided in each cylinder determines normal, the output of the data bit corresponding to its own cylinder position becomes Lo, and the data bit corresponding to the other cylinders. Is output Hi, and the data synthesized by the wired OR circuit is transmitted to the ECU with the data bit corresponding to the normal position being Lo.
For example, as shown in the figure, the diagnosis signal DI for the first cylinder is a bit No. as a start bit. 0 becomes Lo, and the following bit No. 1 corresponds to the determination result of the first cylinder, is Lo when normal, and all subsequent data bits are Hi. Also, bit No. 7 and 8 are assigned to error bits ER1 and ER2 indicating the presence or absence of abnormality. 9 is a stop bit.

  Similarly, for the second cylinder, bit No. 0 becomes Lo, indicating that it is a start bit. 2 corresponds to the determination result of the second cylinder, is Lo when normal, and all the preceding and subsequent data bits are Hi. Similarly to the first cylinder, the bit No. 7 and 8 are assigned error bits ER1 and ER2 indicating the presence or absence of abnormality. 9 is a stop bit.

Hereinafter, in the third and fourth cylinders, the corresponding data bits are normally Lo, and the others are Hi.
A signal obtained by combining the data from the first cylinder to the fourth cylinder by the wired OR circuit is transmitted to the ECU.

In normal operation, as shown in the figure, the bit No. All the diagnostic signals DI of 1-4 are Lo, and all the error bits ER1, ER2 are Hi.
Next, a data structure when a disconnection abnormality occurs in the second cylinder as shown in FIG.

Since there is no abnormality in the first cylinder, the third cylinder, and the fourth cylinder, the data is the same as in FIG.
When a disconnection abnormality occurs in the second cylinder and the disconnection abnormality is detected by the plug current detection / plug voltage detection circuit 132, the bit No. of the diagnosis signal DI of the second cylinder is detected. 2 becomes Hi, and the error bits ER1 and ER2 become Lo together.
Therefore, the self-diagnosis signal transmitted to the ECU 3 is a bit No. as shown in the lowermost part of FIG. 2 becomes Hi, and other data bit bits No. 1, 3, 4 are high, and error bits ER1 and ER2 are Lo.
Also, depending on the type of error, for example, ER1 is set to Lo for overvoltage and overcurrent, and ER1 is set to Lot for overcurrent or MOS short, or overvoltage and overcurrent are detected separately. If possible, the cause of the abnormality can be distinguished and transmitted by setting ER1 to Lo and ER2 to Hi.

The diagnosis synchronization mode will be described with reference to FIG.
For example, the duty ratio of the drive command signal SI is set to 60% in the heater energization mode, and the duty ratio is switched to 20% in the diagnosis signal synchronization mode, and the start bit of the diagnosis signal DI is set in synchronization with the next falling edge. And output synchronization of the diagnosis can be performed.
Accordingly, it is possible to synchronize the diagnosis signal DI with other cylinders by the GCUs 100 (1 to n) of the respective cylinders that receive the same timing of the drive command signal SI.

  Note that the diagnosis synchronization mode does not necessarily match the duty ratio of the first diagnosis signal synchronization mode, and the output timing of the diagnosis signal DI may be adjusted after a low duty output is performed a plurality of times. Information bits other than the start bit may be synchronized with the falling edge of the signal SI.

  Furthermore, in accordance with the target temperature of the glow plug 10 required for the operating state of the internal combustion engine 3, for example, as a heater energization mode, a high temperature control mode that performs PWM control with a duty ratio of 80% using 1200 ° C. as the target temperature It is possible to switch between three levels: a medium temperature control mode in which PWM control with a duty ratio of 60% is performed with a target temperature of 1100 ° C., and a low temperature control mode in which PWM control with a duty ratio of 40% is performed with a target temperature of 1000 ° C. When the ratio is 20%, the self-diagnosis signal synchronization mode may be switched.

The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit of the present invention.
For example, in the above-described embodiment, as the self-cylinder determining means, the voltage detection resistor 127 and the voltage difference detection resistor 122 provided in the GCU 100 _{(1 to n)} form a resistance ladder circuit, and the cylinder position The position of the cylinder is determined from the resistance value that varies depending on the resistance value, but a resistance ladder circuit including a capacitor may be formed, or may be determined by a memory function.
In addition, the present invention can be applied to both a glow plug using a ceramic glow plug and a metal glow plug.

_{DESCRIPTION OF SYMBOLS} 1 Glow plug energization control system 2 Diesel combustion engine 10 _(1-n) Glow plug 100 ₍ 1- _n) Glow plug energization control unit (GCU)
110 _(1-n) Drive control unit (DCU)
120 _(1-n) Cylinder position determination means (IDU)
130 _(1-n) Self-diagnosis unit (DIU)
140 _(1-n) Control unit (PRG)
3 Engine control unit (ECU)
30 ECU interface I / F
4 Driving condition detection means SI drive command signal DI self-diagnosis signal WIR _SI drive command signal line (drive command signal harness)
WIR _DI self-diagnosis signal line (self-diagnosis signal harness)

JP 2008-63967 A JP 2008-31979 A

Claims (10)

Switching means provided between a glow plug provided for each cylinder of a diesel combustion engine and a power source is opened and closed based on a drive command signal transmitted from an engine control device that controls the operation of the engine, and the glow A glow plug energization control system for controlling energization of a plug,
A plurality of glow plug energization control devices that individually control energization to the glow plugs, and the glow plug energization control device controls opening and closing of the switching means based on at least the drive command signal; And a cylinder position determination means for determining its own cylinder position, and a self-diagnosis unit for detecting abnormality of the glow plug and transmitting a self-diagnosis signal,
As the cylinder position determination means, on the communication wiring path that connects the engine control device and each glow plug energization control device and transmits the drive command signal, inside the drive control unit, or on the communication wiring and the drive control A glow plug energization control system characterized in that a cylinder discriminating resistor is interposed in any one of the insides of connectors that connect parts.   Self-diagnosis signals transmitted from the glow plug energization control device provided for each cylinder of the engine are connected to each other by a wired OR circuit connected to a power supply voltage via a pull-up resistor, and recognized by the cylinder position determination means. 2. The glow plug energization according to claim 1, wherein the output bit of each self-diagnosis signal is changed according to the cylinder of its own, and is output to the engine control device as a group of data frames synthesized by the wired OR circuit. Control system.   The cylinder position determining means includes a plurality of resistors having a predetermined resistance value, forms a resistance ladder circuit with the engine control device, and detects a voltage at a predetermined position detected by the resistance ladder circuit. The glow plug energization control system according to claim 1, wherein the cylinder position is determined from the voltage difference.   4. The glow plug energization control device comprises mode switching means for switching between a cylinder position determination mode for determining its own cylinder position and a drive mode for performing energization control for the glow plug. Glow plug energization control system.   A drive command signal line for transmitting the drive command signal from the engine control device to the glow plug energization control device and a self-diagnosis signal line for transmitting a self-diagnosis signal from the glow plug energization control device to the engine control device are used. The plurality of glow plug energization control devices are connected through one input port and one output port of the engine control device, and the mode switching means is configured to connect the drive command signal line in the cylinder position determination mode. The glow plug energization control system according to any one of claims 1 to 4, wherein the resistance ladder circuit is formed via the self-diagnosis signal line and the self-diagnosis signal line.   In the interface of the engine control device that transmits the drive command signal and receives the self-diagnosis signal, the drive command signal line is grounded on the engine control device side, and the self-diagnosis signal line is connected to the engine control device. The glow plug energization control system according to any one of claims 1 to 5, wherein the glow plug energization control system is raised to a power supply voltage on the side of the power supply.   In the cylinder position determination mode, in the cylinder position determination mode, one of a plurality of resistors provided inside each glow plug energization control device is connected in series between the engine control device and each glow plug energization control device. 7. When the other is connected in parallel, its own cylinder position is determined from a voltage detected by a resistor connected in parallel and a voltage difference between both ends of the resistor connected in series. The glow plug energization control system according to any one of the above.   Switching means provided between a glow plug provided for each cylinder of a diesel combustion engine and a power source is opened and closed based on a drive command signal transmitted from an engine control device that controls the operation of the engine, and the glow A control method of a glow plug energization control system for controlling energization to a plug, comprising a plurality of glow plug energization control devices that individually control energization to the glow plug, the glow plug energization control device, At least a control unit that controls opening and closing of the switching unit based on the drive command signal, a cylinder position determination unit that determines its own cylinder position, and a self-diagnosis unit that detects abnormality of the glow plug and transmits a self-diagnosis signal And at least prior to energizing the glow plug, the mode switching means is set to the determination mode. The method of the glow plug electrification control system characterized by comprising a cylinder position determination process determines the cylinder position provided with the glow plug electrification control apparatus. A drive mode switching step of setting the mode switching means to a drive mode after the cylinder position is identified by the cylinder position determination step;
When energization control to the glow plug is started, the drive command signal is set to a predetermined frequency in the drive mode,
When abnormality of the glow plug and the glow plug energization control device is detected in the drive mode, an individual cylinder failure determination mode switching step for setting the mode switching means to the individual cylinder failure determination mode is provided.
9. The glow plug energization control system according to claim 8, wherein the drive command signal is set to a predetermined frequency in the individual cylinder failure determination mode and is transmitted with a duty ratio that can be received only by a glow plug energization control device in which an abnormality is detected. Control method.   The control method of a glow plug energization control system according to claim 8 or 9, further comprising a self-diagnosis signal synchronization mode for synchronizing output of a self-diagnosis signal output from the glow plug energization control device provided in each cylinder.

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