JPH10103460A - Controller for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an erroneous decision that a gear location is a neutral location when a gear shift switch becomes its opened state in a process switching a transmission. SOLUTION: Voltage between an output terminal P of a gear shift switch 1 and a movable contact M is inputted in a gear location detection voltage generation circuit 2 and gear location detection voltage Vg is obtained. Whether the movable contact M of the gear shift switch 1 is located at the location corresponding to any shift location of a transmission or the gear shift switch 1 is in its opened state is discriminated by inputting gear location detection voltage Vg in a microcomputer 4 and comparing voltage Vg with voltage for decision. When the continuous time for the opened state of the gear shift switch 1 is measured, the continuous time for the opened state is compared with a set value and the continuous time for the opened state becomes the set value or more, it is decided that the transmission is located at a neutral location.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an internal combustion engine that controls a device attached to the internal combustion engine according to a gear position of a transmission.

[0002]

2. Description of the Related Art In an internal combustion engine, when controlling an auxiliary device such as an ignition device or a fuel injection device for an internal combustion engine, a gear position of a transmission provided between the engine and a load is determined as one of control conditions. May be. For example, in an internal combustion engine for a vehicle, it is dangerous to start the engine while the gear position of the transmission is in a position other than the neutral position.Therefore, when the engine is started, ignition is performed only when the gear position is in the neutral position. In some cases, the ignition device is controlled to perform the operation, or the fuel injection device is controlled to perform the fuel injection only when the gear position is at the neutral position.

Further, when a vehicle driven by an internal combustion engine exceeds a predetermined speed limit, the ignition spark of the engine is intermittently misfired so that the engine speed is prevented from increasing beyond the speed limit. The device may be controlled. In this case, without using the vehicle speed sensor, the ignition device may be controlled by detecting the vehicle speed from the rotational speed signal of the internal combustion engine obtained from the ignition device and the gear ratio determined by the gear position of the transmission. Alternatively, the ignition device may be controlled to change the ignition timing characteristics of the internal combustion engine according to the gear position of the transmission and the throttle opening.

As described above, when various controls are performed in accordance with the gear position of the transmission, the gear position detection for detecting the gear position of the transmission having the first to n-th shift positions and the neutral position is performed. A control device for an internal combustion engine including means for controlling a device attached to the internal combustion engine using the gear position detected by the gear position detection device as one of control conditions is used.

Conventionally, as a gear position detecting means, a gear position switch including a gear shift switch linked to a transmission and a gear position determining means for determining a gear position from the state of the gear shift switch is used.

As a normal gear shift switch, first gear shift switches corresponding to first to n-th shift positions of the transmission, respectively.
One of a fixed contact for detecting an n-th shift position, a fixed contact for detecting a neutral position corresponding to a neutral position of the transmission, and a first fixed contact for detecting a shift position corresponding to a gear position of the transmission. A movable contact that contacts the fixed contact for neutral position detection, a first to n-th resistor having one end connected to each of the first to n-th fixed contact for shift position detection and having different resistance values,
The first to n-th resistors have output terminals to which the other ends are commonly connected.

The gear position determining means applies a constant DC voltage between the voltage dividing resistor having one end connected to the output terminal of the gear shift switch and the other end of the voltage dividing resistor and the movable contact of the gear shift switch. Means for determining the selected gear position based on the magnitude of the detection voltage obtained between the output terminal of the gear shift switch and the movable contact, and the movable contact detects the first to n-th shift position. The state where the gear shift switch is in an open state without contacting any of the fixed contacts for use is determined as a neutral position.

In the above gear shift switch, when the movable contact switches from a state in which it is in contact with one of the first to n-th fixed contacts for detecting a shift position to a state in which it is in contact with another fixed contact, For a moment, a state occurs in which the movable contact is not in contact with any fixed contact. When it is determined that the transmission is in the neutral position when the movable contact is not in contact with any fixed contact in the process of switching the transmission, the control unit controls the attached device of the internal combustion engine. It is not preferable because the control means performs control corresponding to the neutral position.

Therefore, in the control device for an internal combustion engine that controls the accessory device of the engine using the gear position detecting means, only when the movable contact of the gear shift switch is in contact with the fixed contact for neutral position detection. It is particularly necessary to provide a means for determining that the transmission is in the neutral position, which is troublesome.

FIG. 4 shows an example of a conventional control device for an internal combustion engine in which a state when a shift position of a gear shift switch is switched is not erroneously determined to be a neutral position. This control device includes a gear shift switch 1, a gear position detection voltage generation circuit 2, a neutral position detection voltage generation circuit 3, and a microcomputer 4, and the microcomputer 4 determines the gear shift position and the neutral position. And a control unit that controls a device attached to the internal combustion engine as a control target 9 in accordance with the determined gear position of the transmission.

In the example shown in FIG. 4, the transmission is configured such that the gear position can be switched in six stages. The gear shift switch 1 has first to sixth fixed contacts S1 to S6 for shift position detection, a fixed contact SN for neutral position detection, and a movable contact M. The gear shift switch 1 is gear-shifted with the fixed contacts S1 to S6 for shift position detection. Resistors R1 to R6 each having a different resistance value are connected between the switch and the output terminal P of the switch.

The gear position detecting voltage generating circuit 2 includes a voltage dividing resistor Ra having one end connected to the output terminal P of the gear shift switch 1 and the other end applied with a constant DC voltage Vcc, resistors R7 and R8, and a capacitor. A noise absorbing circuit comprising C1 and C2 and diodes D1 and D2,
A gear position detection voltage Vg of a different magnitude is output according to the gear position of the transmission.

The neutral position detection voltage generation circuit 3
One end is connected to the fixed contact SN for detecting the neutral position of the gear shift switch 1 and the other end is provided with a resistor Rb to which a constant DC voltage Vcc is applied, resistors R9 and R10, capacitors C3 and C4, and diodes D3 and D4. And a noise absorbing circuit. The neutral position detection voltage generating circuit 3 outputs a neutral position detection voltage VN whose magnitude is substantially Vcc when the transmission is not in the neutral position and substantially zero when the transmission is in the neutral position.

The microcomputer 4 for realizing the gear position determining means and the control means for controlling the control object 9 includes at least an analog / digital converter (A / D converter) 5
, A central processing unit (CPU) 6, a random access memory (RAM) 7, and a read-on memory (ROM)
8 and compares the gear position detection voltage Vg with the shift position determination voltage to determine which of the first to sixth gear shift positions the selected gear position is. Further, by comparing the neutral position detection voltage VN with the neutral position determination voltage, it is determined whether the transmission is at the neutral position.

In the microcomputer 4, the determination of the gear shift position and the determination of the neutral position are performed independently of each other. When the movable contact M of the gear shift switch is in contact with the fixed contact SN for neutral position detection. Is determined that the transmission is in the neutral position.

[0016]

In the conventional control device for an internal combustion engine shown in FIG. 4, in the process of switching the position of the movable contact M of the gear shift switch 1, a state in which none of the fixed contacts comes into contact occurs. In order to prevent erroneous determination that the gear position is in the neutral position when the gear shift switch is in the neutral position, a neutral position detection voltage generation circuit 3 is provided separately from the gear position detection voltage generation circuit 2 so that the movable contact Only when M is in contact with the neutral position detection fixed contact SN, it is determined that the transmission is in the neutral position. Therefore, there has been a problem that the configuration of the control device becomes complicated, the device becomes large, and the manufacturing cost increases.

An object of the present invention is to provide a neutral position detection voltage generation circuit separately from a gear position detection voltage generation circuit, and to perform an erroneous determination of a neutral position in the process of switching the position of a movable contact of a gear shift switch. It is an object of the present invention to provide a control device for an internal combustion engine, which can reduce the size of the device and reduce the manufacturing cost without any problem.

[0018]

The present invention is provided between an internal combustion engine and a load, and uses a first to n-th (n is an integer of 2 or more) shift positions and a neutral position as gear positions. Control for controlling an internal combustion engine having gear position detection means for detecting a gear position of a transmission having the same, and control means for controlling a device attached to the internal combustion engine using one of the gear positions detected by the gear position detection means as a control condition It concerns the device.

In the present invention, the gear shift switch used for the gear position detecting means includes first to n-th shift position detecting fixed contacts respectively corresponding to the first to n-th shift positions of the transmission, and a neutral for the transmission. A fixed contact for detecting a neutral position corresponding to the position;
A movable contact that contacts the first to nth fixed contact for shift position detection when each of the nth to nth shift positions is selected, and a fixed contact for neutral position detection when the transmission is in the neutral position; , The first to n-th
Has first to n-th resistors each having one end connected to the shift position detection fixed contact, and an output terminal to which the other ends of the first to n-th resistors are commonly connected. .
The resistance values of the first to n-th resistors are set to different values.

According to the present invention, when the movable contact of the gear shift switch switches from one of the first to n-th fixed contacts for detecting the shift position to another contact, the gear position of the transmission is in the neutral position. In order to prevent an erroneous determination, the neutral position is set only when the duration of the open state in which the movable contact is not in contact with any of the first to n-th fixed contacts for shift position detection is longer than a certain set value. Is determined.

Therefore, the gear position detecting means of the present invention includes a gear shift switch, a voltage dividing resistor having one end connected to an output terminal of the gear shift switch, the other end of the voltage dividing resistor and a movable contact of the gear shift switch. A DC power supply for applying a constant DC voltage during the operation, and a detection voltage obtained between an output terminal of the gear shift switch and the movable contact is compared with a determination voltage to determine a selected gear position, and the movable contact is determined. A gear position determining means for determining a state in which none of the first to n-th fixed contacts for shift position detection are in contact with an open state; an open state duration detecting means for detecting a duration of the open state; When the duration of the open state detected by the open state duration detecting means exceeds a set value, it is determined that the gear position of the transmission is a neutral position. That constitute the the neutral position determination means.

With the above arrangement, when the movable contact of the gear shift switch is in contact with any one of the first to n-th fixed contacts for detecting the shift position, the movable contact is provided between the output terminal of the gear shift switch and the movable contact. Since the obtained detection voltage is lower than a fixed DC voltage given from the DC power supply and shows different values depending on which fixed contact the movable contact is in contact with, the detected voltage is compared with the determination voltage. , The selected gear position can be determined.

When the movable contact of the gear shift switch is not in contact with any of the first to n-th fixed contacts for detecting a shift position, the detected voltage is substantially equal to a constant DC voltage supplied from a DC power supply. So,
By comparing the detected voltage with the determination voltage, it can be determined that the gear shift switch is open.

The set value of the duration of the open state is sufficiently longer than the duration of the open state that occurs when the gear shift switch is switched, and when the movable contact is in contact with the fixed contact for neutral position detection and the gear shift switch is in the open state. In this case, the value is set to a value smaller than the minimum value of the duration of the open state which normally continues when it is set. With this setting, it is possible to determine that the gear position of the transmission is in the neutral position only when the duration of the open state detected by the open state duration detecting means has exceeded a set value. .

The determination of the selected gear position of the transmission and the determination of whether or not the gear position is at the neutral position are based on one detection voltage obtained between the output terminal of the gear shift switch and the movable contact. Therefore, a circuit for generating a detection voltage for detecting the neutral position is not required.

[0026]

FIG. 1 shows an example of the configuration of a control device for an internal combustion engine according to the present invention. In the figure,
1 is a gear shift switch, 2 is a gear position detection voltage generation circuit, 4 is an analog / digital converter (A / D converter) 5, a central processing unit (CPU) 6, a random access memory (RAM) 7, and a read-on memory ( (ROM) 8. In the example shown in FIG. 1, the microcomputer 4 controls a device attached to the internal combustion engine using the gear position detection means, the neutral position determination means, and the gear position detected by the gear position detection means as one of the control conditions. Control means for controlling the object 9 is realized.

The gear shift switch 1 has first to sixth shift position detecting fixed contacts S1 to S6 respectively corresponding to the first to sixth shift positions of the transmission, and a neutral position corresponding to the neutral position of the transmission. When the fixed contact SN for detection and the first to sixth shift positions of the transmission are respectively selected, the fixed contacts S1 to S6 for shift position detection come into contact with each other, and the transmission is set to the neutral position. A movable contact M that contacts the fixed contact SN for neutral position detection at a given time;
The first to sixth resistors R1 to R1 having one ends respectively connected to the fixed contacts S1 to S6 for detecting the shift position.
6 and an output terminal P to which the other ends of the first to sixth resistors R1 to R6 are connected in common, and the movable contact M is grounded. In this gear shift switch 1, the resistance values of the first to sixth resistors R1 to R6 are set to different values, and R
The relationship of 1 <R2 <R3 <R4 <R6 is established.

The gear position detection voltage generating circuit 2 includes a voltage dividing resistor Ra having one end connected to the output terminal P of the gear shift switch 1, a resistor R7 having one end connected to one end of the voltage dividing resistor Ra, A resistor R8 having one end connected to the other end of R7, capacitors C1 and C2 connected between the other end of the resistor R7 and ground, and between the other end of the resistor R8 and ground, respectively.
And a diode D1 having an anode connected to both ends of the capacitor C1 with the anode facing the ground, and a diode D2 having an anode connected to the other end of the resistor R7. In this gear position detection voltage generating circuit 2, resistors R7 and R8, capacitors C1 and C2, diodes D1 and D
2 constitutes a noise absorbing circuit. A constant DC voltage Vcc output from a DC power supply (not shown) is applied between the other end of the voltage dividing resistor Ra and ground (the movable contact M of the gear shift switch 1) and between the cathode of the diode D2 and ground.

When the movable contact M of the gear shift switch is in contact with the fixed contacts S1 to S6 for detecting the shift position, a constant DC voltage Vcc is applied between the output terminal P of the gear shift switch and the movable contact M by a voltage dividing resistor. Vessel Ra
And resistors R1 to R6, respectively, to obtain divided voltages. From the gear shift position detection voltage generating circuit 2, the gear position detection voltages Vg = Vgi = VccRi corresponding to the first to sixth shift positions of the transmission, respectively. / (Ri + Ra)
(I = 1, 2,..., 6) are output.

When the movable contact M of the gear shift switch is not in contact with any of the first to sixth fixed contacts S1 to S6 for shift position detection (movable contact M
Is switched from a state in which it contacts one of the first to sixth fixed contacts S1 to S6 for shift position detection to a state in which it contacts another fixed contact, and the movable contact M
Is in contact with the neutral position detection fixed contact SN), the gear shift switch 1 is opened.
At this time, the gear shift position detection voltage generation circuit 2 outputs a detection voltage Vg (= Vcc) for detecting an open state.

FIG. 2 shows the case where the gear position of the transmission is in the first shift position (first speed) to the sixth shift position (sixth speed), in the neutral position, and when the gear position is switched. FIG. 5 illustrates an example of a state of a gear position detection voltage Vg.

The gear position detection voltage Vg output from the gear position detection voltage generation circuit 2 is input to the microcomputer 4. The gear position detection voltage Vg input to the microcomputer 4 is converted into a digital signal by the A / D converter 5 and input to the CPU 6. The microcomputer 4 executes the program stored in the ROM 8 to compare the detection voltage obtained between the output terminal of the gear shift switch and the movable contact with the determination voltage to determine the selected gear position, The movable contacts are first to n-th
Gear position discriminating means for discriminating a state in which none of the fixed contacts for shift position detection are in contact with the open state, open state duration detecting means for detecting the duration of the open state, and open state duration detecting means And a neutral position determining means for determining that the gear position of the transmission is a neutral position when the duration of the open state detected by the above becomes equal to or greater than a set value.

In order to determine the gear position and determine whether or not the gear shift switch is open, a determination for determining whether the gear position is in the first position to the sixth position is performed. Voltages V1 to V6, a determination voltage VN for determining whether the gear shift switch is open or not, and a gear position detection voltage Vgi (i = 1, 2, 2).
, 6) are set as shown in Table 1 below, for example.

[0034]

[Table 1] As shown in Table 1, the determination voltages V1 to V6, the determination voltage VN, and the gear position detection voltage Vgi (i = 1, 2,..., 6)
Is established, the gear position (shift position of the gear shift switch) can be determined as shown in Table 2 below by comparing the detection voltage Vg with the determination voltage. The judgment voltages V1 to V6 and VN are equal to RO
It is stored in advance in the data area of M8.

[0035]

[Table 2] Further, the gear position detection voltage Vg is compared with the determination voltage VN at regular intervals (for example, every 5 msec) to determine whether or not the gear shift switch is in an open state, and when it is determined that the gear shift switch is in an open state ( Vg ≧ VN)
If 1 is added to the counter on the AM 7, the duration of the open state can be detected from the accumulated count value of the counter. This accumulated count value is compared with a set count value T corresponding to the set value of the open state continuation time, and when it is detected that the accumulated count value has become equal to or greater than the set count value T (the open state continuation time is equal to the set value). When the above is detected), it can be determined that the gear position of the transmission is the neutral position.

The set value of the open state continuation time is sufficiently longer than the open state continuation time generated in the process of switching the gear shift switch, and is the time during which the transmission is held in the neutral position during the normal switching operation of the transmission. It is set to a value smaller than the minimum value (for example, 1 sec = 1000 msec). As described above, when the time interval for comparing the gear position detection voltage Vg and the determination voltage VN is 5 msec, and the set value of the open state continuation time is set to 1000 msec,
Set count value T corresponding to the set value of the open state continuation time
Is 200 (= 1000 msec / 5 msec). That is, in this case, when it is detected that the count value accumulated in the counter on the RAM becomes 200 or more, it can be determined that the gear position of the transmission is the neutral position. The set count value T is stored in the data area of the ROM 8 in advance.

FIG. 3 is a flow chart showing an algorithm of a program executed by the microcomputer 4 to realize the gear position determining means and the neutral position determining means. The routine of FIG. 3 is performed by interrupting the main routine every time the timer counts a predetermined time (for example, 5 msec).

When the routine shown in FIG.
Reads the gear position detection voltage Vg and compares the detection voltage Vg with the determination voltage VN read from the ROM 8. As a result, when Vg ≧ VN is not satisfied, the counter (NEUCNT) on the RAM 7 is cleared, and the detection voltage Vgi is determined by a subroutine (not shown) using the determination voltages V1 to V6 (Table 1).
(See Table 2) to determine which of the first to sixth shift positions the gear position of the transmission is in.

As a result of comparing the gear position detection voltage Vg with the determination voltage VN, if it is determined that Vg ≧ VN,
After adding (incrementing) 1 to the counter (NEUCNT) on the RAM 7, the accumulated count value of the counter is compared with the set count value T read from the ROM 8. As a result, when NEUCNT ≧ T, FIG.
Is repeated from the beginning. As a result of comparing the accumulated count value of the counter with the set count value T read from the ROM 8, when NEUCCNT ≧ T, the open state duration time is equal to or longer than the set value. At this time, the gear position of the transmission is the neutral position. Is determined.
In this case, 1 is subtracted (decremented) from the count value of the counter (NEUCNT), and the routine of FIG. 3 is repeated from the beginning.

The reason why 1 is subtracted from the count value when it is determined that NEUCCNT ≧ T is that the continuation of the state where the gear position of the transmission is in the neutral position exceeds the set value for a long time. In this case, it is to prevent the count value of the counter from continuing to increase beyond the set count value T.

In the illustrated example, the microcomputer 4 and a program executed by the microcomputer 4 determine a gear position determining means for determining the selected gear position of the transmission, and the open state continuation for detecting the duration of the open state. A time detecting means and a neutral position determining means for determining that the gear position of the transmission is a neutral position when the duration of the open state becomes equal to or greater than a set value are realized.

The result of the determination of the gear position of the transmission determined by the microcomputer 4 is based on the control of the control object 9 such as an ignition device and a fuel injection device attached to the internal combustion engine, using the gear position of the transmission as one of the control conditions. To the controlling means. In the present invention, what kind of control the control means specifically performs is arbitrary.

In the above example, the transmission has the first to sixth shift positions. However, in general, the transmission has the first to n-th (n is an integer of 2 or more) shift positions. The invention can be applied.

[0044]

As described above, according to the present invention, the selected gear position is determined by comparing the detection voltage obtained between the output terminal of the gear shift switch and the movable contact with the determination voltage. And determining that the state where the movable contact is not in contact with any of the first to n-th shift position detection fixed contacts is the open state, and the duration of the open state has exceeded the set value. Since the transmission is sometimes determined to be in the neutral position, the neutral position detection voltage generating circuit for preventing erroneous determination of the neutral position is omitted, and the configuration of the gear position detecting means is simplified. Therefore, the configuration of the control device for the internal combustion engine can be simplified.

[Brief description of the drawings]

FIG. 1 is a circuit diagram partially illustrating a configuration example of a main part of a control device according to the present invention using a block diagram.

FIG. 2 is a diagram showing a change in a gear position detection voltage when a gear shift switch is switched in the control device of FIG. 1;

FIG. 3 is a flowchart showing an example of an algorithm of a program executed by a microcomputer in order to realize a gear position determining means in the control device of FIG. 1;

FIG. 4 is a circuit diagram partially showing the configuration of a conventional control device using a block diagram.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 gear shift switch 2 gear position detection voltage generation circuit 3 neutral position detection voltage generation circuit 4 gear position determination circuit 5 analog-to-digital converter 6 CPU (central processing unit) 7 RAM 8 ROM 9 control target S1 to S6 first to sixth Fixed contact for detecting shift position of SN Fixed contact for detecting neutral position M Moving contact R1 to R6 First to sixth resistors P Output terminal Ra Resistor for voltage division

Claims (1)

[Claims] 1. A gear position of a transmission which is provided between an internal combustion engine and a load and has first to n-th (n is an integer of 2 or more) shift positions and a neutral position as gear positions. A gear position detecting means for detecting, and a gear position detected by the gear position detecting means as one of control conditions.
A control unit for controlling a device attached to the internal combustion engine, wherein the gear position detection unit includes first to n-th shift positions corresponding to the first to n-th shift positions of the transmission, respectively. An n-th fixed contact for detecting a shift position;
A fixed contact for detecting a neutral position corresponding to a neutral position of the transmission; and a fixed contact for detecting the first to n-th shift positions when the first to n-th shift positions of the transmission are respectively selected. A movable contact that comes into contact with the fixed contact for neutral position detection when the transmission is in the neutral position, and a first through n-th fixed contacts respectively connected to the first through n-th shift position detection fixed contacts. An n-th resistor, the first to n-th resistors;
A gear shift switch in which the other ends of the resistors have an output terminal connected in common, and wherein the resistance values of the first to n-th resistors are set to values different from each other; and an output terminal of the gear shift switch. A voltage dividing resistor having one end connected to a DC power supply for applying a constant DC voltage between the other end of the voltage dividing resistor and the movable contact; and an output terminal of the gear shift switch and a movable contact. A state in which the selected gear position is determined by comparing the detection voltage obtained in between with the determination voltage, and the movable contact is not in contact with any of the first to nth shift position detection fixed contacts. Gear position determining means for determining the open state, open state duration detecting means for detecting the duration of the open state, and the open state duration detected by the open state duration detecting means. The transmission for an internal combustion engine control apparatus characterized by comprising a neutral position determination means gear position is determined to be in the neutral position of when it is more than the value.