JP2741646B2 - Engine electronic control unit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic control unit which is connected to a mechanism for controlling an intake air amount and a fuel supply amount of an engine, and outputs a drive signal to a step motor for driving the mechanism.

[0002]

2. Description of the Related Art A step motor is attached to a mechanism for controlling an intake air amount and a fuel supply amount of an engine, and calculates an intake air amount and a fuel supply amount based on an engine state and a running state. It is configured to output a drive signal to the step motor so that the intake air amount and the fuel supply amount are obtained.

[0003]

With the above configuration, when an abnormality occurs in a part of a plurality of excitation windings provided in the step motor, the step motor cannot be driven to rotate and the intake air amount cannot be increased. And the amount of fuel supply cannot be controlled, which may cause engine stall.

In this case, a bypass passage is provided in an increase / decrease control mechanism controlled by a step motor, and even when the step motor becomes uncontrollable, a minimum intake air amount and fuel supply amount are secured through the bypass passage. Although it is conceivable to prevent the engine from stalling, there arises a problem that the structure becomes complicated and the cost increases.

In view of the above problems, an object of the present invention is to provide a throttle valve control device capable of securing a minimum intake air amount and a minimum fuel supply amount without providing a bypass passage or the like.

[0006]

In order to achieve the above object, a first aspect of the present invention is a plurality of excitation windings provided in a step motor for driving a control mechanism for increasing or decreasing the intake amount or fuel supply amount of an engine. An electronic control unit that outputs a drive signal to the plurality of excitation windings, wherein abnormality detection means for detecting abnormality occurring in at least one excitation winding based on a current value flowing through each of the plurality of excitation windings, and the abnormality is detected. In this case, there is provided a holding means for energizing another normal excitation winding and holding the rotation position of the step motor at a predetermined position.

According to a second aspect of the present invention, in the first aspect of the present invention, the holding means includes an amount of current supplied to each of the normal excitation coils before the abnormality is detected. The present invention is characterized by comprising a current supply amount increasing means for further increasing.

Further, the invention according to a third aspect of the present invention is directed to an electronic control device for outputting a drive signal to a plurality of excitation windings of a step motor for driving a mechanism for increasing / decreasing an intake air amount of an engine and controlling an ignition timing. Abnormality detecting means for detecting an abnormality occurring in at least one excitation winding based on a current value flowing through each of the excitation windings, and an ignition timing advance for advancing the ignition timing by a predetermined angle when the abnormality is detected. And a corner means.

[0009]

A plurality of exciting windings are attached to the stepping motor. If an abnormality such as a disconnection occurs in a part of the exciting windings, the stepping motor cannot be driven to rotate, but the remaining windings cannot be rotated. By energizing a normal excitation winding, the rotation position of the motor is held at a predetermined position, and a minimum intake air amount and a fuel supply amount are secured so as not to stall.

Incidentally, the amount of the drive signal supplied to the remaining normal excitation windings output at the time of this abnormality is larger than the amount of current supplied to the respective excitation windings at the time of normality, so that the holding force at the predetermined position is increased. The rotation position of the step motor is increased to be surely held at a predetermined position.

In addition to the above, when an abnormality occurs in a part of the exciting winding, the ignition timing is advanced to increase the engine output so as not to stall.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, reference numeral 1 denotes an engine, and the engine 1 is provided with an intake passage 2 having an air filter 21 at a tip thereof.
An injector 22 for injecting fuel pumped from the fuel tank is mounted. Further, a throttle valve 31 connected to the step motor 3 and controlling to increase or decrease the passage area of the intake passage 2 is provided between the air filter 21 and the injector 22. The throttle valve 31 is provided with an opening sensor 32 for detecting the actual opening of the throttle valve 31 and a spring 33 for constantly biasing the throttle valve 31 in the closing direction.
The engine 1 includes a spark plug 11 and the engine 1
A detection signal output from the phase sensor 42 and the opening degree sensor 32 is input to the controller 4, and the driver 4 turns on the ignition switch 41 by the driver D. Then, the opening degree, ignition timing, fuel injection amount, and fuel injection timing of the throttle valve 31 are calculated, and a control signal based on the calculation result is output to the ignition plug 11, the injector 22, and the step motor 3.

Incidentally, the stepping motor 3 has a rotor 50 made of a cylindrical permanent magnet whose north and south poles face each other along the longitudinal direction of the rotating shaft. As shown in FIG. And a so-called hybrid permanent magnet type step motor in which eight fixed magnetic poles 58 to 58 are provided.
An excitation coil is wound around each of .about.58. Among these exciting coils, the first magnetic pole 51, the third magnetic pole 53, the fifth magnetic pole 55, and the seventh magnetic pole 57 are alternately arranged along the circumferential direction with the N pole and the S pole.
The first and second magnetic poles 52, 54, 54, and 56 are connected to each other in the direction in which the magnetic poles are excited.
The eighth magnetic pole 58 is connected alternately along the circumferential direction in the direction in which the N pole and the S pole are excited to form the second excitation winding 62. Then, the first magnetic pole 51 and the fifth
The magnetic pole 55 and the N pole are excited, and the third magnetic pole 53 and the seventh
The energized state of exciting the magnetic pole 57 to the S pole is a first phase, and the second exciting winding 62 is excited to the second magnetic pole 52 and the sixth magnetic pole 56 to the N pole, and the fourth magnetic pole 54 and the eighth The energized state of exciting the magnetic pole 58 to the S pole is a second phase, and the state of energizing the first exciting winding 61 in a direction opposite to the first phase is a third phase. The state in which the electric current was applied in the direction opposite to the second phase was referred to as a fourth phase.

Therefore, the rotor 50 is at the rotation position shown in FIG. 2 when the energized state is the first phase, and when the second phase energized is added to this state, the rotor 50 moves clockwise in FIG. When the first-phase power supply is stopped and only the second-phase power supply is performed, the power supply rotates further 0.9 degrees. In this way, by sequentially energizing two adjacent phases from the first phase to the fourth phase while simultaneously energizing the two phases, the rotor 50
Can be rotated in steps of 0.9 degrees.

In the case of the present embodiment, when the throttle valve 31 is fully closed, the rotor 50 is moved to the position shown in FIG.
When the rotor 50 is turned 0.9 degrees clockwise from the state shown in FIG.
Is set to be a rotational position where is held.

When the ignition switch 41 is turned on as described above, the controller 4 applies a small current to the first excitation winding 61 and the second excitation winding 62 before performing drive control on the step motor 3. Energize and check for abnormalities such as disconnection in each excitation winding. The contents of this check are as shown in FIG.
1 to check whether an abnormality has occurred in the first excitation winding 61 (S1). If an abnormality has occurred in the first excitation winding 61, the process proceeds to S2, in which a similar abnormality check is performed on the second excitation winding 62, and an abnormality has also occurred in the second excitation winding 62. , The energization command in any of the first to fourth phases cannot be performed, so that no energization command is issued to both excitation windings, and the subsequent control of the step motor 3 is stopped.

If the first excitation winding 61 has an abnormality and the second excitation winding 62 is normal, S2 to S2
Then, the process proceeds to step S4, and the second excitation winding 62 is energized in the second phase. Before the step motor 3 is energized, the throttle valve 31 is fully closed. In this case, as described above, the step motor 3 is held when both the first phase and the second phase are energized. It is in. Therefore, when only the energization in the second phase state is performed in S4, the rotor 50 rotates clockwise by one step, that is, 0.9 degrees, and the throttle valve 31 is opened by an opening corresponding to this.

On the other hand, when the first excitation winding 61 is normal and the second excitation winding 62 is abnormal, the process proceeds from S1 to S6 via S5, and the process proceeds to S6. The energization in the state of the third phase is performed. The energization to the third phase state can be seen from the energized state of the first and second phase states corresponding to the fully closed state of the throttle valve 31, the second phase state alone and the second and third phase states. , The rotor 50 rotates 2.7 degrees from the fully closed state. It should be noted that both the energization in the third phase state in S6 and the energization in the second phase state in S4 increase the energization amount from the time of normal control to surely rotate the rotor 51, and to ensure the rotation at the rotated rotational position. , And this state is maintained without performing subsequent drive control on the step motor 3. By the way, when both the first excitation winding 61 and the second excitation winding 62 are normal, the normal control for the step motor 3 is performed after the check flow shown in the drawing is completed.

The first exciting winding 61 and the second exciting winding 6
If an abnormality occurs in at least one of the two,
The engine stall prevention effect is improved by increasing the output of the engine 1 by increasing the fuel injection amount while increasing the ignition timing (S7).

The above embodiment is for a gasoline engine, and the step motor 3 for opening and closing the throttle valve 31 was checked. However, a step motor is attached to the fuel pump of the diesel engine, and the fuel is supplied by the step motor. The above-described check flow according to the present invention is also applied to a case where the ejection amount is variably controlled. In this case, the fuel injection timing may be advanced instead of the ignition timing.

[0021]

As is apparent from the above description, according to the present invention, even if an abnormality occurs in the step motor, the control mechanism for increasing / decreasing the intake air amount or the fuel supply amount can be driven slightly to the open side. Engine stall can be prevented without providing a bypass passage or the like in these increase / decrease control mechanisms.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration to which a control device according to the present invention is applied;

FIG. 2 is a sectional view showing the structure of a step motor.

FIG. 3 is a flowchart showing control contents of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Engine 2 Intake passage 3 Step motor 4 Controller 11 Spark plug 22 Injector 31 Throttle valve 32 Opening sensor 41 Ignition switch 42 Phase sensor

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02D 43/00 301 F02D 43/00 301K 45/00 345 45/00 345Z F02P 5/15 F02P 5/15 L H02P 8/30 H02P 8/00 302A

Claims (3)

(57) [Claims] An electronic control device for outputting a drive signal to a plurality of excitation windings provided in a step motor for driving an increase / decrease control mechanism of an intake air amount or a fuel supply amount of an engine, wherein each of the plurality of excitation windings Abnormality detecting means for detecting an abnormality that has occurred in at least one excitation winding based on a current value flowing through the motor, and when the abnormality is detected, energizes another normal excitation winding to determine the rotational position of the step motor. An electronic control unit for an engine, comprising: holding means for holding at a predetermined position. 2. The power supply system according to claim 1, wherein said holding means includes a power supply amount increasing means for increasing a power supply amount to said normal other excitation windings than a power supply amount supplied to each excitation winding before said abnormality detection. The electronic control device for an engine according to claim 1, wherein 3. An electronic control unit for outputting a drive signal to a plurality of excitation windings of a step motor for driving a control mechanism for increasing / decreasing an intake air amount of an engine and controlling an ignition timing.
Abnormality detecting means for detecting an abnormality occurring in at least one excitation winding based on a current value flowing through each of the plurality of excitation windings, and ignition for advancing an ignition timing by a predetermined angle when the abnormality is detected An electronic control unit for an engine, comprising: timing advance means.