JP2929477B2 - 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 with improved responsiveness to load fluctuations.

[Prior Art] Generally, in engine speed control during idling operation, feedback control is performed so that the engine speed becomes constant based on the deviation between the actual engine speed and the target engine speed. Actuators such as an idle speed control valve (ISCV) interposed in the bypass passage are controlled to increase or decrease the intake air amount of the engine, thereby controlling the engine speed to be constant.

In this case, for an engine, an external load such as an air conditioner or a power steering is provided with a switch for detecting the operation of these devices, and a signal from the switch is detected to perform an increase correction of the air amount. And JP 59
-65542, JP-A-60-134841, JP-A-60-3
The prior art is disclosed in, for example, Japanese Patent No. 5151.

[Problems to be Solved by the Invention] However, conventionally, in order to increase and correct the amount of air when an external load is applied to the engine, it is necessary to wait for the feedback result of the engine speed. Therefore, there is a possibility that the engine speed temporarily decreases significantly. In addition, since the correction itself is set uniformly, there is a problem that precise control cannot be expected.

[Object of the Invention] The present invention has been made in view of the above circumstances, and enables an engine that can quickly and precisely correct an intake air amount according to a load, and that can always maintain a constant engine speed. It is an object of the present invention to provide a rotation speed control device.

Means for Solving the Problems In order to achieve the above object, an engine speed control apparatus according to the present invention provides an engine speed feedback control of an engine speed to a target speed by an actuator for increasing / decreasing an intake air amount of the engine. In the numerical control device, as shown in FIG. 1, based on a function using a basic fuel injection amount representing the operating state of the engine as a parameter and a function using the engine cooling water temperature as a parameter regardless of the state of an external load on the engine. And a basic control amount setting means M1 for setting a basic control amount of the actuator for feedback control.

[Operation] In the engine speed control device having the above-described configuration, the basic control amount setting means M1 uses the basic fuel injection amount representing the operating state of the engine as a parameter and the engine cooling function regardless of the state of the external load on the engine. A basic control amount of the actuator for increasing or decreasing the intake air amount of the engine is set based on a function using the water temperature as a parameter, and the engine speed is feedback-controlled based on the basic control amount.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 2 and subsequent figures show an embodiment of the present invention, FIG. 2 is a schematic diagram of an engine control system, and FIG. 3 is a flowchart showing an idle speed control procedure.

(Configuration of Engine Control System) In FIG. 2, reference numeral 1 denotes an engine (a horizontally opposed four-cylinder engine in the figure) main body, and an intake manifold 3 and an exhaust manifold 4 are connected to a cylinder head 2 of the engine main body 1, respectively. Has been established.

A throttle chamber 6 is connected to an upstream side of the intake manifold 3 via an air chamber 5, and an upstream side of the throttle chamber 6 is connected to an air cleaner 8 via an intake pipe 7. Further, an intake air amount sensor 9 is provided immediately downstream of the air cleaner 8.

Further, a throttle valve 6a provided in the throttle chamber 6 is connected to a throttle opening sensor 10a and an idle switch 10b for detecting that the throttle valve is fully closed, and an idle switch 10b is provided in a bypass passage 11 for bypassing the throttle valve 6a. A speed control valve (ISCV) 12 is interposed.

The ISCV 12 is an actuator composed of a known linear solenoid valve or the like. The valve opening degree increases or decreases according to the duty ratio of a drive pulse signal, and the air amount in the bypass passage 11 increases or decreases.

An injector 13 is disposed immediately upstream of each intake port of each cylinder of the intake manifold 3, and a cooling water temperature sensor 14 is provided in a cooling water passage (not shown) forming a riser formed in the intake manifold 3. It is coming.

Further, an O2 sensor 16 faces an exhaust pipe 15 communicating with the exhaust manifold 4. Reference numeral 17 denotes a catalytic converter.

A crank rotor 18 is fixed to a crankshaft 1a of the engine body 1, and a crank angle sensor including an electromagnetic pickup or the like that detects a projection (or a slit) corresponding to a predetermined crank angle on the outer periphery of the crank rotor 18. 19 are opposed.

(Circuit Configuration of Control Device) On the other hand, reference numeral 20 denotes a control device (ECU) including a microcomputer, and the CPU 20, the ROM 22, the RAM 23,
The I / O interface 24 is connected to each other via a bus line 25, and a predetermined stabilized voltage is supplied from a constant voltage circuit 26.

The ECU 20 controls the actuator for feedback control based on a function using the basic fuel injection amount representing the operating state of the engine as a parameter and a function using the engine coolant temperature as a parameter, regardless of the state of the external load on the engine. The engine speed control function provided with the basic control amount setting means for setting the basic control amount is realized, and other control functions such as fuel injection control and ignition timing control are realized.

The constant voltage circuit 26 is connected to a battery 28 via a relay contact of an ECU relay 27, and a relay coil of the ECU relay 27 is connected to the battery 28 via a key switch 29.

Further, the input ports of the I / O interface 24 are connected to the sensors 9, 10a, 14, 16, and 19, respectively.
The idle switch 10b and the air conditioner switch 30 are connected, and the relay contact of the ECU relay 27 is connected to monitor the battery voltage VB. On the other hand, the output port of the I / O interface 24 is connected to the ISCV 12 and the injector 13 via a drive circuit 31.

The ROM 22 stores a control program and fixed data for various controls.The RAM 23 stores output signals of the sensors and switches after data processing and data processed by the CPU 21. Have been.

The CPU 21 calculates a fuel injection amount, an ignition timing, and the like according to a control program stored in the ROM 22, outputs a drive pulse width signal to the injector 13, an ignition signal to a not-shown ignition plug, and the like, and outputs an ISCV signal.
The duty ratio of the drive pulse signal with respect to 12 is calculated, and the amount of air in the bypass passage 11 is controlled to keep the idle speed constant.

(Operation) Next, the operation of the embodiment having the above configuration will be described with respect to idle speed control based on the flowchart of FIG.

This flowchart shows a program that is repeated every predetermined time or every predetermined period.
Reads the intake air amount Q from the intake air amount sensor 9, and reads the engine speed N based on the output signal of the crank angle sensor 19 in step S102.

Next, the process proceeds to step S103, and an engine load such as the basic fuel injection amount Tp is calculated based on the intake air amount Q read in step S101 and the engine speed N read in step S102 (Tp = K × Q / N; K is a constant).

The engine load may be the intake pipe pressure instead of the basic fuel injection amount Tp.

Next, the process proceeds to step S104, in which a load correction value F (Tp) is set by a function using the basic fuel injection amount Tp calculated in step S103 as a parameter, and the process proceeds to step S105, in which the coolant temperature TW from the coolant temperature sensor 14 is set. Is read, and step S106 is read.
, A water temperature correction value G (TW) is set by a function using the cooling water temperature TW as a parameter, and the routine proceeds to step S107.

In step S107, the engine speed N is feedback-controlled to the target speed NSET by adding the load correction value F (Tp) set in step S104 and the water temperature correction value G (TW) set in step S106. The basic duty ratio DUTY for ISCV12 for (DUTY = F (Tp) +
G (TW)), and proceeds to step S108.

That is, in response to the feedback control of the engine speed N to the target speed NSET, a load correction value F (Tp) representing the operating state of the engine is added to the basic duty ratio DUTY for the ISCV12 as a feedforward element in advance, and the control response I try to improve the nature.

Then, proceeding to step S108, the air conditioner switch 30
It is determined whether or not the air conditioner is ON based on the signal of (1). If the air conditioner is OFF, the process jumps to step S110.
In this case, the process proceeds from step S108 to step S109, where the basic duty ratio DUT set in step S107 is set.
Add air conditioner correction value DAC to Y (DUTY = DUTY + DA)
C), and proceed to step S110.

In step S110, the engine speed N and the target speed N
If N> NSET, the process jumps to step S112. If N> NSET, the feedback amount DFB is reduced in step S111 (DFB = DFB-1), and step S1 is performed.
Proceed to 12.

In step S112, the engine speed N and the target speed NSET are compared again. If N ≧ NSET, the process jumps to step S114. If N <NSET, the feedback amount DFB is increased in step S113 (DFB = DFB + 1). ), And proceed to step S114.

Then, in step S114, the feedback amount DFB is added to the basic duty ratio DUTY to obtain a control duty ratio (DUTY = DUTY + DFB). In step S115, a drive pulse signal having the control duty ratio DUTY is output to the ISCV12 and the program exits.

As described above, the control amount for the ISCV 12 is set in advance by using the basic fuel injection amount Tp or the like representing the engine operating state as a parameter regardless of the state of the external load, for example, the air conditioner operating state detected by the air conditioner switch 30. Since the correction value F (Tp) is added, even when a sudden load change due to an air conditioner operation or the like is applied, the increase correction of a new air amount can be minimized.
Quick and precise correction is possible.

[Effects of the Invention] As described above, according to the present invention, regardless of the state of the external load on the engine, the function using the basic fuel injection amount representing the operating state of the engine as a parameter and the engine coolant temperature as the parameters. A basic control amount setting means for setting a basic control amount of the actuator for increasing or decreasing the intake air amount based on the function, the operation state of the engine is always reflected in the control amount of the actuator, and a sudden decrease in the external load on the engine is provided. Even for a small fluctuation, the intake air amount can be corrected quickly and precisely, and an excellent effect such as a smooth engine rotation can be obtained by preventing a decrease in the engine speed.

[Brief description of the drawings]

FIG. 1 is a claim correspondence diagram showing a basic configuration of the present invention, and FIG.
FIG. 1 shows an embodiment of the present invention, FIG. 2 is a schematic diagram of an engine control system, and FIG. 3 is a flowchart showing an idle speed control procedure. M1 ... Basic control amount setting means

Claims (1)

(57) [Claims] 1. An engine speed control device for feedback-controlling an engine speed to a target speed by an actuator for increasing / decreasing an intake air amount of the engine, the engine speed indicating an operation state of the engine regardless of a state of an external load on the engine. An engine having basic control amount setting means for setting a basic control amount of the actuator for feedback control based on a function having a basic fuel injection amount as a parameter and a function having an engine coolant temperature as a parameter; Speed control device.