JPH05187335A - Intake controller for internal combustion engine - Google Patents

Abstract

PURPOSE:To provide an intake controller of internal combustion engine which can take appropriate measures when a failure occurs in an intake control valve which is set in correspondence to each cylinder. CONSTITUTION:This is an intake controller in which intake control valves 151 to 154 which are driven by actuators 191 to 194, respectively, are provided at intake ports 141 to 144 which correspond to each cylinder 121 to 124 of internal combustion engine 11. When it is judged that a failure has occurred in actuators 191 to 194 at step 501, the failed cylinder 121 to 124 is stored at step 503, and the routine against failure at step 504 is started. That is, warning display 38 is done at step 505, and cylinder in rest and cylinder in operation are determined at step 601 in correspondence to the failed actuators 191 to 194. The control valve of cylinder in rest is set to half-open condition by stopping conductivity of electricity, and the cylinder in operation is set to the reduction cylinder control mode at step 603.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine in which an intake control mechanism is provided for each intake port corresponding to each cylinder, and in particular, when a failure occurs in the intake control mechanism, a countermeasure is improved. The present invention relates to an intake control device.

[0002]

2. Description of the Related Art An intake control valve is provided for each of a plurality of intake ports corresponding to a plurality of cylinders of an internal combustion engine, and the intake timing is controlled by controlling the opening and closing of the intake control valve. Intake control devices for engines are known. The intake control valve set in each intake port for controlling the intake timing in this manner has actuators corresponding to the respective motor mechanisms, and these actuators are driven and controlled by the electronic control unit composed of a microcomputer or the like. I am trying to do it.

In the intake control device thus constructed, when a failure occurs in the actuator for driving the intake control valve set in each intake port, the intake control valve corresponding to the failed actuator becomes inoperative. In operation, it becomes impossible to control the intake of the cylinder in which this intake control valve is installed, the intake air amount is different in each of the plurality of cylinders, the torque fluctuation becomes large, and as a result, the drivability deteriorates. For example, it will be difficult to transfer this vehicle to a repair shop.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and is sufficient even when one actuator of the intake control valve set in each intake port fails. Driving control is possible,
It is an object of the present invention to provide an intake control device for an internal combustion engine, which enables operation transfer of a vehicle to a repair shop or the like based on a warning display or the like.

[0005]

An intake control device for an internal combustion engine according to the present invention has an intake control valve set for each of a plurality of intake ports set corresponding to each cylinder of the internal combustion engine. A throttle valve that is opened and closed in response to an accelerator pedal operation is provided in an intake passage that is commonly communicated with the intake port. Each of the plurality of intake control valves has a failure occurrence of these intake control valves. An intake control valve and a suction control valve for which the failure determination is performed by the failure countermeasure setting means in a state in which at least one failure in the intake control valve is determined by the failure determination means. The control is performed so that the valve state of the intake control valve corresponding to the cylinder that is symmetrical with the cylinder corresponding to is the same.

Here, in the failure countermeasure setting means, driving of the intake control valve corresponding to the defective intake control valve and the cylinder corresponding to the cylinder corresponding to the defective intake control valve is stopped,
Alternatively, control for stopping driving of all intake control valves is executed.

[0007]

In the intake control device for an internal combustion engine configured as described above, in the event that a failure occurs in one of the plurality of intake control valves set in each intake port, at least the malfunction of the intake control valve The valve state, that is, the opening degree is made equal to the valve state of the intake control valve corresponding to the cylinder that is symmetrical to the cylinder corresponding to the intake control valve. As a result, the intake amount of the cylinder corresponding to the failed intake control valve becomes equal to the intake amount of the cylinder located symmetrically to the failed cylinder. Therefore, the torque generated in the cylinders that ignite and explode at equal intervals can be made substantially the same, and the rotational fluctuation of the internal combustion engine can be suppressed. As a result, this vehicle can be transported to a repair shop or the like relatively smoothly according to an instruction such as a warning display.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of a four-cylinder engine 11. Intake air is supplied to the cylinders 121 to 124 of the engine 11 from intake ports 141 to 144 branched from the collective intake passage 13, respectively. Intake valves 151 to 154 are provided at the inlets from the intake ports 141 to 144 of the cylinders 121 to 124, respectively, and exhaust valves 161 to 154 are provided to the cylinders 121 to 124, respectively. 164 communicate with the exhaust passage 17, respectively.

The intake ports 141-144 corresponding to the cylinders 121-124 respectively have intake control valves 181-184.
Is provided. The intake control valves 181 to 184 are driven and controlled by actuators 191 to 194, respectively, and the actuators 191 to 194 are controlled by an electronic control unit 20 composed of a microcomputer. The electronic control unit 20 includes a central processing unit (C
PU) 201, ROM 202 for storing control programs,
Further, a RAM 203 for storing control data and the like is provided, and these CPU 201, ROM 202, RAM 203 and the like and a data bus
An input / output unit 205 connected by 204 is included.

For the engine 11, although not shown in detail, a crank angle sensor 2 for generating a pulse signal in a state where the pistons of the cylinders 121 to 124 are located at the top dead center (TDC).
1, a rotation speed sensor 22 that generates a pulse signal for each predetermined crank angle, a torque sensor 2 that detects the torque of each cylinder
3, an intake pipe pressure sensor 24, a throttle sensor 25, a vibration detection sensor 26 for detecting the vibration of the engine 11, an emission detection sensor 27, and the like are provided, and the detection signals from these sensors 21 to 27 are electronic control unit 20. Is input to the input / output unit 205 of the.

Further, in the engine 11, fuel injection control means 28 for controlling the fuel injection amount and fuel injection timing by the injector, and ignition timing control means 29 for setting the ignition timing.
Further, a supercharger 30 for supercharging intake air and an intake air heater 31 for heating intake air are set in the intake passage 13 and further, the input / output unit 205 performs learning control according to operating conditions. Signals from the learning control means 32 and the cooling water temperature adjusting means 33 are supplied.

The intake passage 13 is provided with a throttle 35 that is driven by an actuator 34 to which a command is given from the electronic control unit 20 in response to an operation of an accelerator pedal (not shown). Detected by the temperature sensor 36 and supplied to the control unit 20. Further, the warning lamp 38 is controlled to be turned on by the transistor 37 whose conduction is controlled by a command from the electronic control unit 20.

In the intake mechanism configured as described above, the throttle 35 has a conventional structure shown by a chain line with respect to the output from the accelerator sensor (not shown) corresponding to the depression amount of the accelerator pedal as shown in FIG. In comparison, as shown by the solid line, the opening side is set larger. As a result, the intake pressure during the intake stroke of the engine is set to approximately atmospheric pressure to reduce pump loss and improve fuel efficiency. Then, the amount of intake air to each cylinder of the engine is adjusted by the opening time and the opening of the intake control valve, and is controlled so that a desired torque according to the accelerator operation amount is generated.

Here, the throttle includes a linkless throttle and a wire type throttle that moves by a link. In the case of the linkless throttle, its operating state is stored in the map stored in the ROM 202 or the like in the electronic control unit 20 as in the closing timing of the intake control valve. In the case of a wire type throttle, a non-linear cam is set at a connecting portion between the wire and the throttle, which is not particularly shown, so that a required characteristic can be set by the cam.

The intake control valves 181 to 184 are controlled by actuators 191 to 194, respectively, and their opening degrees are set by the amount of electricity supplied to each of the actuators 191 to 194. Then, for example, with the energization of the actuators 191 (192 to 194) stopped, the intake control valves 181 (182 to 18) are
4) is set at a position of 45 ° as shown in FIG. 3, and is set and held in a half-open state.

FIG. 4 shows one intake control valve 181 in detail and shows a butterfly type circular valve body 41 in the intake port 141 set in the intake manifold 40. The valve body 41 is integrally attached to the rotary shaft 42, and the intake port 141 is rotated as the rotary shaft 42 rotates.
It comes to open and close the intake passage. The rotating shaft 42 is attached to the wall of the manifold 40 by a bearing mechanism, and its lower end is guided into the actuator 191 set below the manifold 40.

The actuator 191 is provided with a case 43, and a rotary shaft 42 is set at the central shaft portion of the case 43. A cylindrical magnet member 44 is integrally attached to the rotary shaft 42. The magnet member 44 is magnetized so that the magnetic poles are arranged along the circumferential surface.

A pair of electromagnetic coils 451 and 452 wound around magnetic bodies are provided at positions on the outer circumference of the magnet member 44 in the case 43 so as to be axially symmetric, and these electromagnetic coils 451 and 452 are provided.
Is supplied with an exciting current in response to a command from the electronic control unit 20. Further, permanent magnets 461 and 462 having opposite magnetic poles with the magnet member 44 sandwiched therebetween are set in portions where the positions are perpendicular to the electromagnetic coils 451 and 452.

In the intake control valve 181, constructed as described above, when a predetermined exciting current is applied to the electromagnetic coils 451 and 452 of the actuator 191, the magnetic poles formed by the electromagnetic coils 451 and 452 and the magnetic poles of the magnet member 44. Therefore, the rotary shaft 42 is rotated to a position where the valve body 41 is fully opened, for example. Then, by applying an exciting current in the opposite direction to the electromagnetic coils 451, 452, the valve body 41 is brought into a fully closed state in which the intake port 141 is closed. Then, when the exciting current to the electromagnetic coils 451 and 452 is cut off, the permanent magnet is applied to the magnet member 44.
Only 461 and 462 act, and the half-open state is reached as shown in FIG.

The control of the intake air amount is performed as shown in FIG. 5, and its basic valve opening timing (TO) is set as shown in Table 1 corresponding to the rotation speed of the engine 11. The load is detected based on the amount of depression of the accelerator pedal.
Further, the closing timing of the intake control valve is advanced from the bottom dead center (BDC) of the intake, and this closing timing is obtained from the calculation formula shown below.

TC = TCBSE + TTC + FTC + TR
TC + BTC + NTC + NETC + TDC However, TC valve closing timing (advance amount relative to bottom dead center) TCBSE valve closing basic advancing amount TTC shown in Table 1 A / F correction advancing amount during transition FTC Combustion temperature correcting advancing amount TRTC Corrected advance amount of traction control BTC Corrected advance amount of intake brake control during deceleration NTC Corrected advance amount of knocked NETC Corrected advance amount of air amount control TDC Actuator time-dependent corrected advance amount

[Table 1] Although the formula for calculating the valve opening timing is not shown in particular, the concept of calculating the valve closing timing can be naturally used. Table 2 shows the basic valve opening timing (T
O) is indicated by the advance amount with respect to the top dead center of the intake air.

[0022]

[Table 2] The intake control valves 181-184 are connected to the intake ports 141-14.
The expected failure pattern in the intake control system set to 4 is that not all of the actuators 191 to 194 that drive the control valves 181 to 184 fail at the same time, but one of them fails first, and then a short time later. After the passage of time, the second actuator will fail.

If the actuators 191 to 194 for driving the intake control valves 181 to 184 shown in the embodiment have a failure and the failure is detected in the electronic control unit 20, the exciting current to the failed actuator is detected. When cut off, the intake control valve corresponding to this actuator is set to the position of 45 ° as shown in FIG. 3 and is set to the half open state. As a result, when the actuator for driving the intake control valve fails, the variation in the intake air amount between the cylinders becomes as shown in FIG. 6, and the variation in the intake air amount directly leads to the torque variation between the cylinders. , The drivability may be deteriorated, and the engine may be stopped.

In this intake air control system, the intake air amount is controlled by the closing timing of the intake control valve additionally set near the upstream side of the intake valve. Then, the opening of the throttle is controlled in the opening direction as shown in FIG. Therefore, the intake air amount decreases as the closing timing of the intake control valve on the horizontal axis of FIG. 6 advances.

When the actuator fails, the intake control valve is set not to be fully closed but to be half open. When the intake control valve is closed 40 ° CA before intake BDC when the actuator is normal, the intake air amount at that time is Q1.

On the other hand, when the actuator is out of order, the opening of the control valve is halved as compared with the normal state, and the intake air amount decreases, and the intake end timing is delayed to increase the intake air amount. Changes to increase. Then, when both are set to be just about the same, the intake air amount at that time becomes the same Q1 as in the normal state.

The intake control valve when the actuator is normal is
Assuming that the intake air is closed at 20 ° CA before BDC, the intake air amount of the cylinder with the normal actuator is Q2. In this case, since the intake air amount of the cylinder in which the actuator has failed remains Q1, the intake air amount of the cylinder in which the actuator has not failed becomes larger than the intake air amount of the cylinder in which the actuator has failed.

The action to be taken in case of failure differs depending on whether the throttle is a linkless throttle or a wire type throttle. The action to take in case of failure of the actuator for driving the intake control valve will be described below by taking the linkless throttle as an example. ..

First, the failure determination of the actuator is made based on the change of the current or voltage supplied to the exciting coils 451 and 452 of the actuator, or the change of the pressure waveform between the intake valve and the control valve. The electronic control unit 20 makes the determination based on a change in the pressure waveform of the surge tank and the like.

In the process at the time of failure, when the electronic control unit 20 determines a defective actuator, the control for stopping the energization to other normal actuators is performed, and the intake air corresponding to all the cylinders 121 to 124 is respectively taken. Set all control valves 181-184 to half open. Then, the characteristic of the linkless throttle with respect to the accelerator sensor is changed to the failure map in the backup memory set in the electronic control unit 20. FIG. 7 shows an example of the changed characteristic, which is determined by the required value of the accelerator generation torque characteristic shown in FIG. 8. In this example, P,
The plan of Q and R is shown.

Here, it is understood that the generated torque and the intake air amount have substantially the same meaning, and therefore one of the actuators fails and the actuators 191 to 191 to 181 to 184 of the intake control valves 181 to 184 corresponding to all cylinders, respectively. When all the current to 194 is stopped, the intake air amount at that time becomes lower than the maximum air amount in the normal state.

As a characteristic after the change of the linkless throttle, it is important how to connect the "0" point of the intake air amount and the Q1 (or T1) point. The characteristics can be freely changed and set.
The selection of this characteristic can be freely selected based on the design concept and the like, and here, three plans of P, Q, and R are assumed.

Specifically, the plan P has a feeling that does not change from the normal state up to the accelerator depression amount AC1 in FIG. 8, and a feeling that the torque does not further increase after AC1 does not change. In plan Q, the feeling is the same as normal when the accelerator depression amount is up to AC2, but after the AC2 is exceeded, the torque rise becomes slower than normal. Furthermore, in the case of the R plan, the feeling of the torque increase amount being low from the beginning with respect to the driver's accelerator depression amount,
The feelings of P, Q, and R are changes that are hardly noticeable to an ordinary driver.

FIG. 9 shows the flow of this processing. First, in step 501, the actuator failure determination is performed. Then, if it is determined that all the actuators are normal, the routine proceeds to step 502, where the control valve opening (closing) timing for normal time is calculated. If the defective actuator is determined, the routine proceeds to step 503, where the cylinder of the defective actuator is stored. And step 50
At 4, the failure countermeasure routine starts.

In this failure countermeasure routine, a warning instruction is given in step 505, and the warning lamp 38 is turned on to notify the driver. Then, in step 506, a command to stop energizing the actuators corresponding to all the cylinders is issued, and in step 507, a command to change the linkless throttle to the map as shown in FIG. 7 is issued.

FIG. 10 shows another example of the processing, and the same processing as the processing of FIG. 9 is executed up to steps 501 to 505. Then, if the failure countermeasure routine is started in step 504 and a warning instruction is issued in step 505, in step 601, a deactivated cylinder and a working cylinder are determined. Specifically, the cylinder in which the actuator has failed and the cylinder that is set symmetrically with this cylinder are set as idle cylinders, and the remaining cylinders are set as operating cylinders.

For example, in the case of a 4-cylinder engine of # 1 to # 4, the explosions occur in the order of # 1, # 3, # 4 and # 2, and if the actuator of the cylinder of # 1 fails. For example, # 1 and # 4 are idle cylinders, and # 2 and # 3 are active cylinders.

Then, in step 602, a map change command for the linkless throttle is appropriately generated, and in step 60
Calculate the opening (closing) timing of the intake control valve for reduced cylinder control in 3 and
Further, in step 604, the ignition timing and the fuel injection amount for the cut-off cylinder control are calculated. Table 3 shows the basic valve closing timing in the cut-off cylinder control. However, when it is determined that the torque fluctuation is out of the drivability tolerance, the intake control valve is closed at a partial load even at full load.

[0039]

[Table 3] Similarly, the basic valve opening timing is set as shown in Table 4.

[Table 4] Table 5 below shows combinations of idle cylinders that stop energization and working cylinders that perform cut-off cylinder control for failed cylinders.

[0040]

[Table 5] The explanation so far has been made for the linkless throttle. However, even in the case of the wire type throttle, the control by the cut-off cylinder control is possible. That is, as shown in FIG. 10, the actuator of the failed cylinder is determined,
The energization of the actuator is stopped under the conditions shown in Table 5, and the cut-off cylinder control is executed for the remaining cylinders. In this case, in the case of the wire type throttle, the processing of step 602 in FIG. 10 cannot be performed as in the case of the linkless throttle, so that the processing of changing the map is omitted.

In the case of this wire type throttle, the processing for changing the throttle characteristic cannot be performed in the processing shown in FIG. 9. Therefore, if a measure is taken to make the intake control valves of all cylinders half-opened, almost the same as before the countermeasure. Although the relationship between the accelerator operation amount and the generated torque cannot be obtained, the following measures can be considered in anticipation of the driver's delicate accelerator operation.

That is, when it is detected that a failure has occurred in one of the actuators that drive the intake control valve,
As in the case of the process in FIG. 9, the energization of the actuators of the intake control valves of all cylinders is stopped, and all of these intake control valves are set to the half-open state. Then, the subsequent adjustment of the torque is not performed by the electronic control unit, but is performed by operating the accelerator pedal according to the driver's sensitivity.

In this case, when viewed from the driver's side, it is often felt that the generated torque becomes large for the same depression amount of the accelerator pedal, but the driver feels the generated torque sensuously and naturally accelerates. You can expect driving operation to reduce the amount of depression, and even when the throttle characteristic is steep,
The vehicle can be driven by a delicate and delicate accelerator pedal operation by the driver.

FIG. 11 shows the state of torque in each cylinder. In the normal state shown in FIG.
Torque is evenly generated in each cylinder corresponding to the explosion stroke. If the actuator that drives the intake control valve corresponding to the # 1 cylinder fails,
In the state where no action is taken, no torque is generated in the failed cylinder # 1 as shown in FIG.

When the actuator of the intake control valve corresponding to the cylinder # 1 as described above fails, the procedure shown in FIG. 9 is performed and all the intake control valves corresponding to all the cylinders are set to the half open state. By doing so, torque is evenly generated in each of the cylinders # 1 to # 4 as shown in FIG.

When the cylinder cut-off processing as shown in FIG. 10 is performed, for example, when the actuator of the cylinder # 1 fails, the actuators of the intake control valves corresponding to the cylinders # 1 and # 4 are not energized. It is stopped and the other cylinders are set to the reduced cylinder control mode. Therefore, the torque generated in each cylinder is as shown in FIG.

In the embodiment described above, the intake control valve is set to the half-open state when not energized, but it may be partially opened to 1/3 or the like. In addition to stopping the energization of the intake control valve to make the intake amount of the failed cylinder equal to that of the equally spaced cylinder, it also detects whether the intake control valve has a fully closed failure or a fully opened failure. The intake control valve may be driven to the same valve state as that of the defective intake control valve.

As described above, according to the embodiment to which the present invention is applied, when the intake control valve fails, the torques generated in the cylinders that are ignited and exploded at equal intervals are made equal, and the engine generated torque fluctuation, rotation fluctuation, and vibration are generated. Therefore, the vehicle can be driven and run relatively smoothly even after the breakdown.

Particularly, when only the intake control valves of the cylinders located at equal intervals with respect to the cylinder provided with the defective intake control valve are stopped, the decrease in the torque generated by the engine is suppressed to the minimum. It is possible to suppress fluctuations in the generated torque. In addition, when the intake control valves of all the cylinders are stopped so that the equally generated torque is generated in the cylinders at equal intervals, it is possible to easily take countermeasures after a failure.

[0050]

As described above, according to the intake control device for an internal combustion engine of the present invention, it seems that a failure occurs in the actuators that drive the intake control valves set in the intake ports corresponding to the respective cylinders. In this case, the intake control for each cylinder is performed in a state where the driver does not feel any abnormality, and the vehicle can be transferred to a repair shop according to instructions such as a warning display. Safety will be secured when a failure occurs.

[Brief description of drawings]

FIG. 1 is a configuration diagram for explaining an intake control system of an internal combustion engine according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a throttle opening characteristic in this embodiment.

FIG. 3 is a diagram illustrating a control state of an intake control valve used in this embodiment.

4A is a vertical cross-sectional configuration diagram illustrating the structure of the intake control valve, and FIG. 4B is a cross-sectional configuration diagram corresponding to line bb in FIG. 4A.

FIG. 5 is a diagram for explaining operating states of an intake valve and an intake control valve set in a cylinder.

FIG. 6 is a diagram for explaining the relationship between the opening timing of the intake control valve and the intake air amount.

FIG. 7 is a diagram for explaining an operation map of a linkless throttle and showing a relationship between an accelerator depression amount and a throttle opening.

FIG. 8 is a diagram for explaining a relationship between an accelerator depression amount and generated torque.

FIG. 9 is a flowchart illustrating a control flow of the above embodiment.

FIG. 10 is a flowchart illustrating a control flow of another embodiment.

11 (A) to (D) show a normal state, a fault state, and
The figure which shows the state of the torque produced in each cylinder when the countermeasure of the said Example is implemented.

[Explanation of symbols]

11 ... Engine, 121-124 ... Cylinder, 141-144 ... Intake port, 151-154 ... Intake valve, 161-164 ... Exhaust valve, 181
~ 184 ... Intake control valve, 191-194 ... Actuator, 20
… Electronic control unit, 38… Warning lamp.

Claims (3)

[Claims] 1. A plurality of intake control valves set in each of a plurality of intake ports set respectively corresponding to each cylinder of an internal combustion engine, and an intake passage commonly connected to the plurality of intake ports. A throttle valve that is set and is opened / closed in response to an operation of the accelerator pedal, and a failure determination unit that is set corresponding to each of the plurality of intake control valves and that detects a failure occurrence in these intake control valves; In a state where at least one failure in the intake control valve is determined by the determination means, the intake control valve for which the failure is determined and the intake control valve corresponding to the cylinder symmetrical to the cylinder corresponding to the intake control valve are determined. An intake control device for an internal combustion engine, comprising: a failure countermeasure setting means for making the valve state of the same. 2. The failure countermeasure setting means stops driving of the intake control valve corresponding to the defective intake control valve and the cylinder symmetrical to the cylinder corresponding to the defective intake control valve. An intake air control device for an internal combustion engine as described. 3. The intake control device for an internal combustion engine according to claim 1, wherein the failure countermeasure setting means stops driving of all intake control valves.