JP2501912B2 - Engine speed control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine speed control device, and in particular, controls the engine speed when at least one of the detectors for detecting an idle state is abnormal. Regarding things.

[Conventional technology]

A conventional engine rotation speed control device detects an idle state by, for example, a vehicle speed sensor or an idle switch, and when an idle state is detected, a rotation speed feedback correction amount according to a deviation between an actual rotation speed and a target rotation speed and The opening degree of the air control valve provided in the bypass conduit bypassing the throttle valve is electrically controlled based on the combined amount with the basic air amount for maintaining the target rotation speed.

[Problems to be Solved by the Invention]

Since the conventional engine speed control device is as described above, the feedback control of the idle speed is executed without detecting the failure of the detector for detecting the idle state. For this reason, when decelerating the vehicle, for example, if the vehicle speed sensor is malfunctioning and it is determined that the vehicle is stopped, and in this case the idle switch is on and it is determined that the vehicle is in the idle state, feedback control indicates that the actual rotation speed is higher than the target rotation speed. The rotation speed feedback correction amount is reduced to bring the actual rotation speed closer to the target rotation speed, but the actual rotation speed does not decrease due to deceleration, so the rotation speed feedback correction amount is kept small, and as a result, the rotation speed feedback correction amount is reduced. Becomes extremely small. Immediately after shifting from the deceleration state to the idle state, there is a problem that the actual rotation speed drops significantly below the target rotation speed due to insufficient air supply to the engine, or in the worst case engine stall occurs. It was

Further, the same problem as described above occurs when the idle switch fails and remains on even during no-load racing.

The present invention has been made to solve the above problems, and detects an abnormality of a detector for detecting an idle state, and at the time of this abnormality, the lower limit of the rotation speed feedback correction amount is set to reduce the rotation speed. An object of the present invention is to obtain an engine speed control device capable of preventing an abnormal decrease and the like.

[Means for solving the problem]

The engine speed control device of the present invention comprises an abnormality detection means for detecting that at least one of the detectors for detecting an idle state in the device is abnormal, and the control means outputs the abnormality detection signal. Accordingly, when the rotation speed feedback correction amount is equal to or smaller than the predetermined correction amount, the predetermined correction amount is set.

[Work]

When at least one of the detectors is abnormal, the engine speed control device according to the present invention shifts to the idle state to determine the idle state even though the detector is not in the idle state. Therefore, the control means sets the rotation speed feedback correction amount as a lower limit to a predetermined correction amount.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram showing the configuration of an apparatus and the like according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a spark ignition type engine mounted in, for example, an automobile or the like, which sucks main air from an air cleaner 2 through an intake pipe 3 and an intake branch pipe 4. The fuel is injected and supplied into the intake pipe 3 by the electromagnetic fuel injection valve 5. This fuel amount is determined by a fuel control system (not shown), which may be an electronic control unit 20 described later, based on the output signal of the pressure sensor 6 which detects the pressure in the intake pipe 3 by absolute pressure.

Reference numeral 7 denotes a throttle valve for adjusting the main intake air amount of the engine 1 by a driver's arbitrary operation of an accelerator pedal (not shown), 8 a throttle opening sensor for detecting the opening of the throttle valve 7, and 9 a throttle valve. 7 is an idle switch that detects the fully closed state, and is turned on at the time of detection.

10 is a throttle valve 7 located downstream of the fuel injection valve 5.
By-pass conduit 11 for bypassing the bypass conduit is provided between the bypass conduits 10 and is an air control valve for controlling the flow passage cross-sectional area. For example, an electromagnetic control valve having an opening degree according to the duty ratio D of the drive signal is used. There is.

The ignition device of the engine 1 is connected to an ignition control system (which may be an electronic control unit 20 but not shown) that generates an ignition signal from an operating condition parameter of the engine, and the primary of the ignition coil 12 is responsive to the ignition signal. It is composed of an igniter 13 for controlling on / off of electric current, an ignition coil 12, a distributor (not shown), an ignition plug (not shown), and the like.

Reference numeral 14 is a cooling water temperature sensor for detecting a cooling water temperature representing the temperature of the engine 1, 15 is an electric load switch for turning on a load such as an air conditioner, 16 is a neutral switch for generating a torque converter signal of an automatic transmission, 17 Is a vehicle speed sensor that outputs a pulse signal having a frequency proportional to the rotation speed of the axle, and detects the vehicle speed.

Reference numeral 18 is an exhaust pipe, 19 is a catalyst, and 20 is an electronic control unit that operates by being supplied with power from a battery 21 via a key switch 22. The electronic control unit 20 includes a throttle opening sensor 8, an idle switch 9, an ignition coil 12,
Input signals from the cooling water temperature sensor 14, the electric load switch 15, the neutral switch 16, and the vehicle speed sensor 17, and control amount of the air control valve 11 for feedback control of rotation speed and control amount for performing open loop control. Then, the air control valve 11 is driven and controlled.

Next, the electronic control unit 20 will be described with reference to FIG. Reference numeral 100 denotes a microcomputer, which is a CPU2 that calculates the control amount of idle rotation according to a predetermined program.
00, a free-running counter 201 for measuring the rotation cycle of the engine 1, clock measurement every 100 ms, and an air control valve
A timer 202 having a plurality of configurations for measuring the duty ratio D of the drive signal applied to 11, an A / D converter 203 for converting an analog input signal into a digital signal, an input port 204 for directly inputting a digital signal, and a work memory RAM 20
5, ROM206 storing programs such as the flowchart of FIG. 3, output port 20 for outputting drive signals
It is composed of 7, common bus 208, etc. Reference numeral 101 is a first input interface circuit, which waveform-shapes the primary ignition signal of the ignition coil 12 into an interrupt signal and outputs it to the microcomputer 100. When this interrupt signal occurs, CPU200
Reads the value of the counter 201, calculates the cycle of the engine speed from the difference from the previous value, and stores it in the RAM 205. A second input interface circuit 102 removes noise components of the output signals of the throttle opening sensor 8 and the cooling water temperature sensor 14 and outputs the output signal to the A / D converter 203. Ten
Reference numeral 3 is a third input interface circuit, which sets the ON signal of the idle switch 9 and the electric load switch 15, the neutral safety signal from the neutral switch 16 when the switch is ON, and the pulse signal from the vehicle speed sensor 17 to a predetermined level to the input port 204. Output. 104 is an output interface circuit,
Air control valve 1 by amplifying drive signal from output port 207
Output to 1. A power supply circuit 105 supplies power to the microcomputer 100 by making the voltage from the battery 21 a constant voltage when the key switch 22 is turned on.

Next, the operation of this embodiment will be described mainly with reference to FIGS. 3 and 4 in FIGS. 1 to 4. First, in FIG. 3, in step S1, a process shown in FIG. 4 (a) is executed to determine whether the vehicle speed sensor 17 is normal, and a vehicle speed sensor abnormality determination process of setting or clearing a flag of the determination result is performed. .

In FIG. 4 (a), in step S100, it is determined whether or not a pulse is input from the vehicle speed sensor 17 within a predetermined time. If the pulse is input, the vehicle speed sensor 17 is normal, so in step S101. Clear the vehicle speed sensor error flag,
If no pulse is input, the process proceeds to step S102. Step
In S102, it is determined whether the idle switch 9 is off,
If it is off, the routine proceeds to step S103, where the throttle opening sensor 8 is connected to the second input interface circuit 102 and the A / D converter 20.
Whether the actual throttle opening value θ read via 3 is greater than or equal to the first predetermined opening value θ _{1, that} is, the opening of the throttle valve 7 should be surely obtained from the vehicle speed sensor 17 within a predetermined time. It is determined whether or not the opening is equal to or more than the predetermined opening. If the actual throttle opening value θ is equal to or larger than the first predetermined opening value θ _{1, the} vehicle speed sensor 17 is in an abnormal state, so the process proceeds to step S104 and the vehicle speed sensor abnormality flag is set. If it is determined in step S102 that the idle switch 9 is on, or if it is determined in step S103 that the actual throttle opening value θ is less than the predetermined value θ ₁ ,
In either of the cases of processing step S104 and processing of step S101, the processing of step S1 has been completed, and thus the processing moves to the next step S2.

In step S2 of FIG. 3, it is determined from the output from the vehicle speed sensor 17 whether the vehicle speed is, for example, 1.5 km / h or less, that is, whether the vehicle is stopped. If the vehicle is not stopped, the process proceeds to step S19 for open loop control, and if the vehicle is stopped (if the vehicle is actually stopped or the vehicle speed sensor 17 is out of order), the process proceeds to step S3, and FIG. The process shown in is executed to determine whether the idle switch 9 is normal.

In FIG. 4B, in step S200, the actual throttle opening value θ read from the throttle opening sensor 8 is the second predetermined opening value θ _{2 in} the ON region of the idle switch 9.
It is determined whether or not the following. If the second predetermined opening value θ ₂ or less, it is determined in step S201 whether or not the idle switch 9 is on. If it is on, the idle switch normal is determined, and if it is off, the idle switch abnormality is determined. Second
If it is not equal to or less than the predetermined opening degree value θ _{2 of} step S202, it is determined whether or not the idle switch 9 is off. If it is off, the idle switch normal is determined, and if it is on, the idle switch abnormality is determined. Idle switch normal /
Depending on the abnormality determination result, the process proceeds to the next step S5 / step S4.

If the idle switch abnormality determination is made in step S3, the process proceeds to step S4, and after setting the idle switch abnormality flag, the process proceeds to step S7.

If it is determined in step S3 that the idle switch is normal, the process proceeds to step S5, and it is determined whether the idle switch 9 is on. If it is not on, the process proceeds to step S19, and if it is on, the process proceeds to step S6, the idle switch abnormality flag is cleared, and then the process proceeds to step S7.

In step S7, the actual rotation speed is calculated from the rotation cycle of the engine 1.
Calculate Ne. In step S8, the target rotation speed Nt is calculated according to the operating state of the engine 1, for example, the ON / OFF signal of the electric load switch 15, the ON / OFF signal of the neutral switch 16, the water temperature signal from the cooling water temperature sensor 14, and the like. In step S9, the basic air amount Q _BASE that also corresponds to the operating condition
Is calculated. In step S10, it is determined whether or not the timing is every 100 ms. If the timing, the process proceeds to step S11, and if not, the process jumps to step S16.

In step S11, the control gain ΔKI is calculated from the deviation ΔN between the target rotation speed Nt and the actual rotation speed Ne using the ΔN map shown in FIG. In step S12, it obtains the 100ms before the rotation speed feedback correction amount Q revolution speed feedback correction amount of the temporary and adds the control gain ΔKI the _NFB Q _NFB in (previous) '. In step S13, it is determined whether or not at least one of the vehicle speed sensor abnormality flag and the idle switch abnormality flag is set. If it is set, in step S14, a temporary rotation speed feedback correction amount
The larger one of Q _NFB ′ and the predetermined correction amount Q _MIN is set as the rotation speed feedback correction amount Q _NFB , and Q _NFB is updated, and after updating, the process proceeds to step S16. Here, the predetermined correction amount Q _MIN is set to a value such that the actual rotation speed does not fall below the target rotation speed under general operating conditions. If the above-mentioned abnormality flag is not set, in step S15, the temporary rotation speed feedback correction amount Q _NFB 'is set to the rotation speed feedback correction amount Q _NFB , and then the process proceeds to step S16.

In step S16, the basic air amount Q _BASE and the rotation speed feedback Q _NFB are added to obtain the idle speed control air amount Q _ISC . In step S17, the idle speed control air amount Q
_The duty ratio D is calculated by the _ISC using the Q _ISC map shown in FIG. As shown in FIG. 7, the duty ratio D is T when the cycle is T and the ON time of one cycle is T _ON.
It is given as _ON / T x 100 [%]. In step S18, a drive signal with a duty ratio D is output to the air control valve 11 to drive and control it.

On the other hand, if it is determined in step S2 that the vehicle is not stopped, or if it is determined in step S5 that the idle switch 9 is not on, it means that the vehicle is in the non-idle state, so step S19.
Proceed to.

In step S19, the idle speed control air amount Q _ISC is set to the air amount Q _OPEN when entering the open loop control.
After setting, the process proceeds to step S17, and the same process as above is performed.

Although the process returns after the process of step S18, other well-known processes (fuel supply control, ignition timing control) of the main routine (not shown) are performed, and then the process returns to step S1 to repeat the above operation.

FIG. 8 shows (a) operation state, (b) according to the above embodiment.
FIG. 9 is a timing chart showing changes in the state of the vehicle speed sensor 17, (c) state of the idle switch 9, (d) rotation speed feedback correction amount Q _NFB , and (e) actual rotation speed Ne with respect to time t (horizontal axis). . At time t ₁ , the operating state shifts from the idle state to the running state, the idle switch 9 changes from on to off, and the closed loop control shifts to the open loop control. Period running state at time t ₁ ~t _3, open loop control is executed. During this time, the vehicle speed sensor 17 becomes abnormal at time t ₂ , but the vehicle speed sensor abnormality flag is set. In the traveling state up to time t ₃ , the rotation speed feedback correction amount Q _NFB is clipped to the value at the time of shifting to open loop control (time t ₁ ). Time t ₃ in throttle valve 7 is closed shifts from the operation state is a running state to a decelerating state, an idle switch 9 is changed from OFF to ON, the process proceeds to closed loop control. In the deceleration state of the period of time t ₃ ~t _4, the actual revolution speed Ne, but decreases with time, the target rotational speed
Since it exceeds Nt, the rotation speed feedback correction amount Q
_NFB is reduced. However, since the vehicle speed sensor abnormality flag is set, the provisional rotation speed feedback correction amount Q
_{When NFB} 'becomes equal to or smaller than the predetermined correction amount Q _MIN , the rotation speed feedback correction amount Q _NFB is clipped to Q _MIN as shown in the figure. Then, at time t ₄ , the drive range shifts to the neutral range and the deceleration state shifts to the idle state. Immediately after this time t _4, the actual rotational speed Ne is slightly higher than the target rotation speed Nt落込Muga, the sagging amount not greater the difference from the following reasons. Q _NFB is clipped to Q _MIN until time t ₄ , and then the temporary speed feedback correction amount Q _NFB ′ is changed from Q _MIN to Q _MIN.
Rotation speed feedback correction amount is larger than the Q _MIN Q _NFB
Therefore, the response of the increase in the air amount becomes very fast.

Conventionally, as indicated by the alternate long and short dash line, in the deceleration state during the period from time t _{3 to} t ₄ , the rotation speed feedback correction amount Q _NFB is 0.
To reduce. Then, the time t ₄ below the target rotation speed Nt is the actual rotation speed Ne immediately after, but thereby increasing the revolution speed feedback correction amount Q _NFB is 0, which by the poor response of increasing amount of air. Therefore, the lack of air volume caused the actual speed Ne to fall.
Is significantly lower than the target speed Nt.

In the above embodiment, Q _OPEN may be set to a predetermined amount of air, and in this case, the air control valve is set to a predetermined opening corresponding to Q _OPEN during open loop control.

〔The invention's effect〕

As described above, according to the present invention, when at least one of the detectors for detecting the idle state is abnormal, the rotation speed feedback correction amount according to the deviation between the actual rotation speed and the target rotation speed is a predetermined correction value. When the speed is less than the specified amount, the correction amount is set to the predetermined value. There is an effect that the actual rotation speed can be prevented from abnormally lowering from the target rotation speed immediately after shifting to the state.

[Brief description of drawings]

FIG. 1 is a block diagram showing an outline of an apparatus according to an embodiment of the present invention, FIG. 2 is a block diagram showing a concrete structure of an electronic control unit etc. in FIG. 1, and FIG. 3 is a block diagram showing the present invention. FIG. 4 (a) is a flow chart showing vehicle speed sensor abnormality determination processing, FIG. 4 (b) is a flow chart showing idle switch abnormality determination processing, and FIG. 5 is a rotational speed. Deviation Δ
6 is a diagram showing the relationship between N and the control gain ΔKI, FIG. 6 is a diagram showing the relationship between the idle speed control air amount Q _ISC and the duty ratio D, FIG. 7 is an explanatory diagram of the duty ratio, and FIG. FIG. 6 is a timing diagram according to an embodiment of the invention. In the figure, 3 ... intake pipe, 5 ... electromagnetic fuel injection valve, 6 ...
Pressure sensor, 7 ... Throttle valve, 8 ... Throttle opening sensor, 9 ... Idle switch, 10 ... Bypass conduit, 11 ... Air control valve, 12 ... Ignition coil, 13 ... Igniter, 17 ... Vehicle speed sensor, 20 ... electronic control unit, 21 ... battery. The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (1)

(57) [Claims] 1. An air control valve for controlling a passage sectional area of a bypass conduit for bypassing a throttle valve of an engine, and a detection means for detecting an idle state by output signals from a plurality of detectors for detecting an operating state of the engine. And, at the time of detecting the idle state, the air control valve according to a combined amount of a rotational speed feedback correction amount according to a deviation between an actual rotational speed and a target rotational speed and a basic air amount for maintaining the target rotational speed. A rotation speed control device for an engine, the control means electrically controlling the opening degree of the engine, and an abnormality detection means for detecting that at least one of the detectors for detecting the idle state is abnormal. , The control means,
When the abnormality detection signal is received from the abnormality detection means and the rotation speed feedback correction amount is less than or equal to a predetermined correction amount,
An engine rotation speed control device, wherein the predetermined correction amount is set as the rotation speed feedback correction amount.