JP2510245Y2 - Engine combustion control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an engine combustion control device.

[Prior Art] Japanese Patent Application Laid-Open No. 61-1832 discloses a device for controlling combustion of an engine. This device includes a first control unit (first control unit) mounted inside a fuel injection pump that supplies fuel to an engine, and a second control unit (second control unit) arranged outside the fuel injection pump. And are connected to each other via a harness. The internal control unit includes a drive circuit unit for driving an electromagnetic valve (actuator) mounted on the combustion injection pump,
A first microcomputer that outputs a control signal is provided to the drive circuit unit. The second control unit includes a second microcomputer.

In the second microcomputer, basic data according to the operating state is calculated and sent to the first microcomputer. The first microcomputer stores data representing the characteristics of each fuel injection pump (including the solenoid valve), and outputs a control signal to the drive circuit unit based on the basic data and the pump characteristic data.

[Problems to be Solved by the Invention] However, the device disclosed in the above publication has a drawback in that when the first microcomputer fails, combustion control of the engine is not performed and the vehicle cannot run at all.

Regarding backup control when a microcomputer fails, Japanese Patent Laid-Open No. 63-5137, Patent Application Publication 60-
No. 502162 and JP-A-62-23550.

In the device disclosed in Japanese Patent Laid-Open No. 63-5137, when the microcomputer fails, the failure detection unit detects it and switches to control by the auxiliary control unit. However, the auxiliary control unit, which is not normally used, is newly added, and there is a drawback that the cost becomes high although the normal control is not improved.

In Japanese Patent Application Laid-Open No. 60-502162 and Japanese Patent Laid-Open No. 62-23550, backup control is performed when a microcomputer fails by using an ignition device, circuit means, etc. that are normally used for control. However, this backup control is very simple, and it has been difficult to ensure proper traveling.

[Means for Solving the Problems] The present invention has been made to overcome the above problems.
The gist is an actuator for engine combustion control,
A drive circuit unit for driving the actuator, a first control unit including a first microcomputer used to control the drive circuit unit, and a second control unit including a second microcomputer used to control the drive circuit unit. A control unit,
A first harness having a connector at its tip extends from the drive circuit section; and a second harness having a connector at the tip, respectively. The third harness extends, the second
A fourth harness having a connector at its tip extends from the control unit, and the first microcomputer has the fourth harness.
Via the harness and the third harness, operation data from a normal control mode executing means of the second microcomputer, which will be described later, is received, an operation is performed based on this operation data, and a control signal for performing optimum engine combustion control is sent. A control means for outputting to the drive circuit section via a second harness and a first harness; and the second microcomputer,
(A) failure detecting means for detecting a failure of the first control section via the third harness and the fourth harness to activate the failure display section; and (b) via the fourth harness and the third harness, Normal control mode execution means for sending arithmetic data relating to control of the drive circuit section to the first microcomputer;
(C) Emergency control mode executing means for outputting a control signal to the drive circuit section instead of the first microcomputer via the fourth harness and the first harness to perform engine combustion control, and (d) fourth harness Detects whether it is connected to the third harness or the first harness, activates the normal control mode executing means when connected to the third harness, and executes the emergency control mode when connected to the first harness. An engine combustion control device comprising: a mode determining unit that operates the unit.

The mode discriminating means may selectively operate either the normal control mode executing means or the emergency control mode executing means based on a mode signal from an operable switch.

[Operation] Normally, the first control unit is connected to the drive circuit unit via the first harness and the second harness, and is also connected to the second control unit via the third harness and the fourth harness. When the first controller is operating normally, in the second microcomputer of the second controller, the normal control mode executing means is operating, and the calculation data related to the control is the first.
Send to control unit. The first control unit performs a calculation based on this calculation data, and outputs a control signal for performing optimum engine combustion control to the drive circuit unit. In this way, during normal control, the first and second microcomputers cooperate to perform combustion control, so that extremely sophisticated control can be performed.

When the first controller fails, the failure detecting means of the second microcomputer detects this and activates the failure display. The driver can notice the failure of the first control section by operating the failure display section, and can change the connection state by the harness. That is, when a failure occurs, the first harness and the fourth harness are connected to connect the second control unit to the drive circuit unit without the intervention of the first control unit.

In the mode determining means of the second microcomputer, the emergency control mode executing means can be selectively operated based on the connection change of the harness or the mode signal from the operable switch. The emergency control mode execution means outputs a control signal to the drive circuit section instead of the first control section.

As described above, even if the first control unit fails,
By changing the connection state of the harness, the engine combustion control can be reliably performed, and for example, the vehicle can be driven to a repair place. Further, even in the case of this emergency control, by using the second microcomputer, it is possible to perform a higher degree of backup control as compared with the conventional backup control, although it is inferior to the normal control.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.
In FIG. 1, reference numeral 1 is a distributed combustion injection pump. The combustion injection pump 1 includes a pump body 1a and a drive shaft 1b protruding from the pump body 1a. The drive shaft 1b is mechanically connected to the engine 2 and transmits the rotational force of the engine 2. The fuel injection pump 1 further includes a pump unit (not shown).
The pump portion includes a plunger that rotates and reciprocates as the drive shaft 1b rotates, and the forward movement of the plunger pressurizes the fuel. The pressurized fuel is sent to each cylinder of the engine 2 through the plurality of pipes 3.

A solenoid valve 4 (shown only in FIGS. 3 and 4) as a combustion control actuator connected to the pump portion is attached to the pump body 1a of the fuel injection pump 1. The solenoid valve 4 allows the pressurized fuel to escape to the low pressure chamber of the pump body 1a in the open state, and allows the pressurized fuel to be sent to the engine 2 in the closed state. Therefore, the closing start timing of the solenoid valve 4 determines the fuel injection start timing, and the time from the closing of the solenoid valve 4 to the opening thereof determines the fuel injection amount.

The pump body 1a of the fuel injection pump 1 includes the solenoid valve 4 described above.
A drive circuit unit 5 for driving the solenoid valve 4 is mounted, and a fuel temperature sensor unit 6 and a rotation sensor unit 7 are mounted. These fuel temperature sensor unit 6 and rotation sensor unit 7 are shown only partially in FIG. The rotation sensor unit 7 is
For example, it is provided with two toothed rotors fixed to the drive shaft 1b, and two electromagnetic pickups respectively arranged around these rotors. One of the rotating bodies has one tooth, and the electromagnetic pickup facing the one tooth outputs one pulse with one rotation of the drive shaft 1b. Hereinafter, this pulse is referred to as a reference pulse. The other rotating body has a large number of teeth, for example, 36 teeth, and another electromagnetic pickup facing this rotating body outputs 36 pulses with one rotation of the drive shaft 1b. Hereinafter, this pulse is referred to as a scale pulse.

The pump body 1a further includes a first control unit 10
(First control unit) is attached. The first control unit 10 is mounted on the outer surface of the pump body 1a and covered with a cover 1c. On the other hand, the second control unit 20 (second control unit) is arranged apart from the fuel injection pump 1. As will be described later, the first control unit 10 and the second control unit 20 cooperate with each other to control the solenoid valve 4 in the normal control state.

Next, the connection means 30 for connecting the drive circuit unit 5, the fuel temperature sensor unit 6, the rotation sensor unit 7, the first control unit 10, and the second control unit 20 to each other will be described in detail. Harnesses 5a, 6a, 7a extend from the drive circuit unit 5, the fuel temperature sensor unit 6, and the rotation sensor unit 7, and these harnesses 5a, 6a, 7a
Male connectors 31, 32, and 33 are attached to the tips of the respective connectors. Male connectors 31, 32, 33 are common harness 34
Is connected to a female connector 35 attached to one end of the. A male connector 36 is attached to the other end of the common harness 34. The harnesses 5a, 5b, 5c, 34 constitute a first harness. On the other hand, two harnesses 10a, 10b are extended from the first control unit 10,
A female connector 37 is attached to the tip of one harness 10a (second harness), and the other harness 10b.
A male connector 38 is attached to the tip of the (third harness). In addition, the harness from the second control unit 20
20a (4th harness) is extended, this harness 2
A female connector 39 is attached to the tip of 0a.

The connection means 30 may be provided when the vehicle is shipped or in a normal state.
Is in the state shown in FIG. That is, the female connector 37 of the first control unit 10 is connected to the male connector 36 of the common harness 34, and the male connector 38 is the second control unit 39.
Is connected to the female connector. In this state, the first
The control unit 10 includes the drive circuit unit 5 and the fuel temperature sensor unit.
6, which is connected to the rotation sensor unit 7 and the second control unit 20, and the second control unit 20 is directly connected to the drive circuit unit 5, the fuel sensor unit 6, and the rotation sensor unit 7. There is no connection.

The connecting means 30 can be changed to the state shown in FIG. 2 in an emergency described later. That is, the male connector of the common harness 34
36 is connected to the female connector 39 of the second control unit 20. In this state, the drive circuit unit 5, the fuel temperature sensor unit 6, and the rotation sensor unit 7 are connected to the second control unit 20, and the first control unit 10 has no connection.

The second control unit 20 is connected to the power supply Vb and grounded. Further, the second control unit 20 is connected with an accelerator sensor 41, a boost pressure sensor 42, and a failure display lamp 43 (failure display section).

As shown in FIG. 3, the first control unit 10 includes a first microcomputer 100 and a constant voltage circuit 120. The second control unit 20 also includes a second microcomputer 200 and a constant voltage circuit 220.

FIG. 3 shows a state in which the connection means 30 is in a normal connection state and the microcomputers 100 and 200 cooperate to perform normal engine combustion control. The power supply voltage Vb is
It is connected to the power supply line 221 of the second control unit 20 and also connected to the power supply line 121 of the first control unit 10 via the harnesses 20a and 10b. The constant voltage circuits 120 and 220 receive the power supply voltage Vb and supply the constant voltage Vcc to the components in the microcomputers 100 and 200 and the control units 10 and 20 described later, respectively.

The ground wire GND of the first control unit 20 is grounded,
Ground wire G of the first control unit 10 via the harnesses 20a, 10b
It is connected to ND '.

First microcomputer 100 of first control unit 10
And the second microcomputer 200 of the second control unit 20
Can perform data communication via the harnesses 10b and 20a. That is, the first control unit 10 includes the transmission transistor 122 and the resistor 123, and the transistor 122 and the resistor 123 are connected to the photocoupler 224 of the second control unit 20. Then, when a high level signal is supplied from the first microcomputer 100 to the base of the transistor 122, the transistor 122 is turned on, and in response thereto, the photo coupler 224 is turned on, and the low level signal from the photo coupler 224 is turned on. The signal is input to the second microcomputer 200. In this way,
Data can be sent from the first microcomputer 100 to the second microcomputer 200.

Similarly, the second control unit 20 includes a transmission transistor 222 and a resistor 223.
2 and the resistor 223 are the photocoupler 124 of the first control unit 10.
It is connected to the. As a result, data can be sent from the second microcomputer 200 to the first microcomputer 100.

The data to be communicated by the microcomputers 100 and 200 will be described later.

Further, a modified reference pulse Rf 'and a modified scale pulse Sc', which will be described later, are sent from the first microcomputer 100 to the second microcomputer 200.

Furthermore, one of the input ports of the second microcomputer 200 (hereinafter referred to as the limp port) is connected to the ground line GND 'of the first control unit 10 so that a low level mode signal, which will be described later, becomes a first signal. 2 is input to the microcomputer 200.

The rotation sensor unit 7 has one terminal connected to the power supply line 121 of the first control unit 10 via the harnesses 7a, 34, 10a to receive the supply of the power supply voltage Vb, and the other terminal connected to the ground line GN.
It is connected to D '. The rotation sensor unit 7 sends the reference pulse Rf and the scale pulse Sc to the first microcomputer 100 as the drive shaft 1b of the fuel injection pump 1 rotates.

The fuel temperature sensor unit 6 has one end connected to the pull-up resistor 125 built in the first control unit 10 and the other end connected to the ground line GND ′ via the harnesses 6a, 34, 10a. The voltage at the connection point between the pull-up resistor 125 and the fuel temperature sensor section 6 is a signal representing the fuel temperature Tf and is not shown in A /
It is input to the first microcomputer 100 via the D converter.

The drive circuit unit 5 is connected to the first via the harnesses 5a, 34, 10a.
It is connected to the power supply line 121 of the control unit 10 and supplied with the power supply voltage Vb. The control terminal is a grounded-emitter transistor.
Connected to 126 collectors. This transistor 126
Receives a pulsed control signal from the first microcomputer 100 as a base and outputs a control signal corresponding to this control signal to the drive circuit unit 5.

The first microcomputer 100 is provided with the virtual circuit means shown in FIG. 3 by executing the program stored in the ROM. The details will be described below.

The communication control means 101 performs transmission by controlling the transistor 122, and at the same time, the phototransistor 124
Reception is performed by receiving the output from.

In the pulse signal processing means 102, the scale pulse Sc is divided into a corrected scale pulse Sc ′ which is output one by one each time each cylinder reaches a specific stroke, and the reference pulse Rf is also corrected by a predetermined process. ′
Becomes

In the rotation speed calculation means 103, the adjacent scale pulse S
The rotation speed N of the engine 2 is calculated from the time interval of c.
The data of the rotation speed N is sent to the second microcomputer 200 by the communication control means 101.

The actual angle calculation means 104 calculates a current rotation angle Θ (hereinafter referred to as a real angle) with respect to a specific rotation position of the drive shaft 1b of the fuel injection pump 1 based on the reference pulse Rf and the scale pulse Sc.

In the pulse width calculation means 105, the period for closing the solenoid valve 4 is calculated as the rotation angle range of the drive shaft 1b based on the data of the target injection amount Q described later sent from the second microcomputer 200 to the communication control means 101. Then, the rotation angle range is converted into the dimension of time based on the engine rotation speed N. Therefore, this calculation result represents the time width of the pulse as the control signal for causing the solenoid valve 4 to perform the closing operation. In the above calculation, the correction is made according to the fuel temperature Tf from the fuel temperature detecting means 106, and the correction is made according to the pump characteristic Po from the pump characteristic storing means 107 including a RAM or the like.

In the pulse timing calculation means 108, the starting point of the pulse as a control signal corresponding to the closing start timing of the solenoid valve 4 based on the later-described target injection timing T data sent from the second microcomputer 200 to the communication control means 101. Is calculated as the rotation angle of the drive shaft 1b, and this rotation angle is converted into the dimension of time based on the engine rotation speed N. In this calculation as well, correction is added according to the fuel temperature Tf and the pump characteristic Po.

In the pump characteristic storage means 107, individual pump characteristic data (including solenoid valve characteristics) obtained by performing a test for each fuel injection pump 1 before shipment is written.

The pulse output control means 109 is activated by the scale pulse Sc and outputs a pulse as a control signal based on the calculation results of the pulse width calculation means 105 and the pulse timing calculation means 108. In response to this pulse, the solenoid valve 4 performs the closing operation.

In the second microcomputer 200, by executing the program stored in the ROM, the mode discriminating means 202 and the normal control mode executing means 2 shown in FIG.
00a and the emergency control mode execution means 200b shown in FIG.

In the mode discriminating means 202, when the level of the mode signal input to the limp port is low, the normal control mode executing means 200a shown in FIG. 3 is activated, and when the signal level is high, the emergency control mode shown in FIG. The execution means 200b is activated. In the state of FIG. 3, the limp port is the ground wire GN.
Since it is connected to D ', the mode signal is at a low level, and therefore the normal control mode executing means 200a is activated.

The normal control mode execution means 200a includes means described below.

The communication control means 201 performs transmission by controlling the transistor 222, and at the same time, the phototransistor 224
Reception is performed by receiving the output from.

In the injection amount calculation means 203, the accelerator sensor 41 is basically used.
Data of accelerator operation amount Ac from the communication control means 201
The rotation speed N received from the first microcomputer 100 at
The target injection amount Q is calculated from the data of 1. In this calculation, the compensation amount according to the boost pressure from the compensation amount calculation means 204 is added.

The compensation amount calculating means 204 calculates the compensation amount based on the data of the boost pressure Bo from the boost pressure sensor 42. Since the boost pressure pulsates according to the stroke of each cylinder, the sampling timing is determined based on the modified reference pulse Rf ′ and the modified scale pulse Sc ′, and the boost pressure Bo is always sampled in the specific stroke of the specific cylinder. Is going.

The injection timing calculation means 205 calculates the target injection timing T of fuel based on the data of the accelerator operation amount Ac and the engine rotation speed N.

The data of the target injection amount Q and the target injection timing T are
It is sent to the first microcomputer 100 by the communication control means 201.

In the failure detection means 206, the first microcomputer 100
Determine the failure of. That is, both microcomputers
It is determined whether or not the data communication between the communication control means 101 and 201 of 100 and 200 is normally performed. When it is determined that normal communication is not performed, the failure detection signal Mf is output. The failure display lamp 43 lights up in response to the failure detection signal Mf.

In the above-mentioned normal control state, since the two microcomputers 100 and 200 cooperate with each other, high-speed processing of a large amount of data is possible. Therefore, a very high degree of control can be performed and the solenoid valve 4 operating at high speed can be performed. Ideal for controlling. In addition, the first microcomputer 100 stores data relating to the characteristics of the fuel injection pump 1 to be mounted and uses this as a correction factor, so that accurate fuel injection control is performed regardless of variations in the characteristics of the fuel injection pump 1. It can be performed. The second control unit 20 is independent of variations in the characteristics of the fuel injection pump 1, and can be standardized as a common unit for all fuel injection pumps 1.

In the above-mentioned normal control, when the first microcomputer 100 fails, the fuel injection control becomes impossible. At this time, as described above, since the failure display lamp 43 is turned on by the command from the second microcomputer 200, the driver can notice the failure of the first microcomputer 100. At this time, the driver changes the harness connection state from FIG. 1 to FIG. That is, the male connector 36 of the common harness 34 is removed from the female connector 37 on the first control unit 10 side and connected to the female connector 39 on the second control unit 20 side.

Due to the above connection change, the first control unit 10 becomes independent of the fuel injection control. As shown in FIG. 4, the rotation sensor unit 7 has a second end at one end via the harnesses 7a, 34, 20a.
It is connected to the power line 221 of the control unit 20 and the other end is the ground line G
Connected to ND. The reference pulse Rf and the scale pulse Sc from the rotation sensor unit 7 are sent to the second microcomputer 200.

Due to the above connection change, the drive circuit unit 5 is connected to the harness 5a, 3
The transistor 222 connected to the power supply line 221 of the second control unit 20 via 4, 20a and supplied with the power supply voltage Vb, and the control terminal of which is used for communication in normal control.
Connected to the collector.

One end of the fuel temperature sensor unit 6 has harnesses 6a, 34, 20
Via a, it is connected to the resistor 223 of the second control unit 20 used for transmission during normal control, and the other end is connected to the limp port of the second microcomputer 200. Therefore, the level of the mode signal input to the limp port becomes high, and the mode discriminating means 202 discriminates this, whereby the microcomputer 200 operates the emergency control mode executing means 200b shown in FIG. become.

Next, the emergency control mode execution means 200b will be described in detail.

In the rotation speed calculation means 210, the adjacent scale pulse S
The rotation speed N of the engine 2 is calculated from the time interval of c.

The actual angle calculating means 211 calculates the actual angle Θ of the drive shaft 1b based on the reference pulse Rf and the scale pulse Sc.
Is calculated.

The pulse width calculation means 212 calculates the pulse width from the accelerator operation amount Ac and the rotation speed N.

In the pulse timing calculation means 213, the accelerator operation amount A
The pulse timing is calculated from c, the rotation speed N, and the actual angle Θ.

The pulse output control means 214 is activated by the scale pulse Sc and outputs a pulse as a control signal to the transistor 222 based on the calculation results of the pulse width calculation means 212 and the pulse timing calculation means 213. In response to this pulse, the solenoid valve 4 performs the closing operation.

The control in the emergency control mode described above is executed based on a simplified calculation based on the accelerator operation amount Ac without performing correction by the fuel temperature, boost pressure, individual pump characteristics, etc. Although inferior in comparison, since the second microcomputer 200 is used, the backup control is advanced compared to the conventional backup control, and the vehicle can be reliably driven to a repair place or the like.

Next, the program executed by the second microcomputer 200 will be described with reference to FIG. When the power switch is turned on, the system is first initialized (step 500). Next, it is determined whether communication with the first microcomputer 100 is normally performed (step 501). When it is normally executed, the normal control mode is executed. That is, the engine speed N is set to the first
Input from the microcomputer 100 (step 502),
The accelerator operation amount Ac is input from the accelerator sensor 41 (step 503), the boost pressure Bo is input from the boost pressure sensor 42 (step 504), and the target injection amount Q is obtained from these data.
Is calculated (step 505) and the target injection timing T
Is calculated (step 506). Next, the target injection amount Q and the target injection timing T are sent to the first microcomputer 100 (step 507).

If communication is not normally performed in step 501 above, the input level of the limp port is determined (step
508). If the level is low, the failure indicator lamp 43 is turned on (step 509). First microcomputer 1
After 00 has failed, the above steps 501, 508, and 509 are repeatedly executed until the driver notices that the failure indicator lamp 43 is lit and changes the connection state of the harness as shown in FIG. 1 to FIG. 43 remains lit.

After the harness connection is changed, in step 508,
It is judged that the input level of the limp port is high, and the following emergency control mode is executed. That is, the rotation speed N is calculated based on the scale pulse Sc (step 510),
The actual angle Θ of the drive shaft 1b is calculated from the scale pulse Sc and the reference pulse Rf (step 511). Next, the accelerator operation amount Ac is input (step 512), and the pulse width is calculated based on the accelerator operation amount Ac and the rotation speed N (step 513) and the pulse timing is calculated (step 514). Next, a pulse output is instructed (step 515). As a result, the output port of the second microcomputer 200 outputs a pulse having the above-calculated timing and width with the input point of the scale pulse Sc as the reference point.

The present invention is not limited to the above embodiment, and various embodiments are possible. For example, the mode signal may be obtained from a switch operated by the driver after changing the harness connection.

Further, it goes without saying that the failure display is not limited to visual display and may be performed by voice.

In the above embodiment, the basic data calculated by the second microcomputer is the target injection amount and the target injection timing, but this basic data differs depending on the mode of the actuator to be controlled.

[Advantages of the Invention] As described above, according to the present invention, even if the first control unit fails, the engine combustion control can be performed to a relatively high degree by using the second microcomputer. Can be driven up to. The second microcomputer performs a very high degree of fuel control in cooperation with the first microcomputer during normal control and is used for both normal control and emergency control, so that it can be effectively utilized.

[Brief description of drawings]

The drawings from FIG. 1 to FIG. 5 show an embodiment of the present invention. FIG. 1 is an overall schematic view showing a connection state of a harness during normal control, and FIG. 2 is a harness during emergency control. 3 is an overall schematic view showing the connection state of the device, FIG. 3 is an avoidance block diagram during normal control, FIG. 4 is a circuit block diagram during emergency control, and FIG.
The figure is a flowchart showing an example of a program executed by the second microcomputer. 2 ... Engine, 4 ... Fuel control actuator (solenoid valve), 5 ... Drive circuit section, 10 ... First control section (first control unit), 20 ... Second control section (second control) Unit), 5a, 5b, 5c, 34 ... 1st harness, 10a ... 2nd harness, 10b ... 3rd harness, 20a ... 4th harness, 31,
35,36,37,38,39 …… Connector, 43 …… Fault display section (fault display lamp), 100 …… First microcomputer, 200
...... Second microcomputer, 200a ...... Normal control mode execution means, 200b ...... Emergency control mode execution means, 202 ...
… Mode discriminating means, 206 …… Failure detecting means.

Claims (2)

(57) [Scope of utility model registration request] 1. An actuator for controlling engine combustion,
A drive circuit unit for driving the actuator, a first control unit including a first microcomputer used to control the drive circuit unit, and a second control unit including a second microcomputer used to control the drive circuit unit. A control unit,
A first harness having a connector at the tip thereof extends from the drive circuit portion, and a second harness having a connector at the tip of the first controller, A third harness extends, a fourth harness having a connector at its tip extends from the second control unit, and the first microcomputer is configured to operate the second microcomputer via the fourth harness and the third harness. The drive circuit section receives the operation data from the normal control mode executing means, which will be described later, performs the operation based on the operation data, and outputs the control signal for performing the optimum engine combustion control through the second harness and the first harness. The second microcomputer detects a failure of the first controller via the third harness and the fourth harness. And (b) a normal control mode executing means for sending the operation data regarding the control of the drive circuit section to the first microcomputer via the fourth harness and the third harness. (C) Emergency control mode execution means for outputting a control signal to the drive circuit section instead of the first microcomputer via the fourth harness and the first harness to perform engine combustion control, and (d) fourth harness Detects whether it is connected to the third harness or the first harness, and when it is connected to the third harness, activates the normal control mode execution means,
An engine combustion control device comprising: a mode determination unit that operates an emergency control mode execution unit when connected to the first harness. 2. An actuator for controlling engine combustion,
A drive circuit unit for driving the actuator, a first control unit including a first microcomputer used to control the drive circuit unit, and a second control unit including a second microcomputer used to control the drive circuit unit. A control unit,
A first harness having a connector at the tip thereof extends from the drive circuit portion, and a second harness having a connector at the tip of the first controller, A third harness extends, a fourth harness having a connector at its tip extends from the second control unit, and the first microcomputer is configured to operate the second microcomputer via the fourth harness and the third harness. The drive circuit section receives the operation data from the normal control mode executing means, which will be described later, performs an operation based on the operation data, and outputs a control signal for performing optimum engine combustion control through the second harness and the first harness. The second microcomputer detects a failure of the first controller via the third harness and the fourth harness. And (b) a normal control mode executing means for sending arithmetic data concerning the control of the drive circuit section to the first microcomputer via the fourth harness and the third harness. (C) Emergency control mode execution means for outputting a control signal to the drive circuit section instead of the first microcomputer via the fourth harness and the first harness to perform engine combustion control, and (d) operable. An engine combustion control device comprising: a mode determination means for selectively operating either the normal control mode execution means or the emergency control mode execution means based on a mode signal from a switch.