JPH0310359Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an idle rotation speed control device for an electronically controlled engine that controls the idle rotation speed to maintain proper idle operation.

[Problems to be solved by conventional technology and invention] In a conventional idle rotation speed control device, the target idle rotation speed is stored in a mask ROM. Therefore, it is impossible for users and dealers to change or modify the target idle rotation speed, which may increase idle vibration or cause engine overheating at the target idle rotation speed in the mask ROM. If such a situation were to arise, the entire computer would need to be replaced, making it difficult for users and sellers to deal with such situations on their own.

An object of the present invention is to provide an idle rotation speed control device for an electronically controlled internal combustion engine that allows users and sellers to easily modify or change the target idle rotation speed by themselves.

[Means for Solving the Problem] In order to achieve this object, the idle rotation speed control device for an electronically controlled internal combustion engine of the present invention sets a predetermined rotation speed stored for read-only during the idling period to a target. As the idle rotation speed,
In an idle rotation speed control device for an electronically controlled internal combustion engine that controls the engine rotation speed by controlling the intake flow rate in a bypass passage that is arranged in parallel to the intake passage section where the throttle valve is installed, an external signal is used to control the engine rotation speed. an external signal input means for inputting an external signal; a storage device that stores an engine rotation speed corresponding to the external signal when the external signal is input and retains the memory even during a period when engine operation is stopped; The gist of the invention is to include target idle rotation speed switching means for setting the stored engine rotation speed as a target idle rotation speed instead of the predetermined rotation speed.

[Operation] In the idle rotation speed control device for an electronically controlled internal combustion engine of the present invention, when the external signal input means inputs an external signal, the storage device stores the engine rotation speed according to the external signal, and the engine operation is stopped during the engine operation stop period. also retains memory. In addition, during the idling period, the engine rotation speed is controlled by controlling the intake air amount in the bypass passage using a predetermined rotation speed stored for read-only as the target idle rotation speed. If the speed is stored, the target idle rotation speed switching means sets the engine rotation speed stored in the storage device as the target idle rotation speed instead of the predetermined rotation speed. Therefore, the idle rotation speed is controlled based on the engine rotation speed stored in a storage device to which data can be written and which retains data even during periods when engine operation is stopped. If the speed is not stored, control is performed based on a predetermined rotation speed stored for read-only purposes.

[Example] Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows the entire electronically controlled engine to which the present invention is applied. Air taken in from the air cleaner 1 is sent to the combustion chamber 8 of the engine body 7 through an intake passage 12 that includes an air flow meter 2, a throttle valve 3, a surge tank 4, an intake port 5, and an intake valve 6. The throttle valve 3 is linked to an accelerator pedal 13 in the driver's cab. The combustion chamber 8 is divided by a cylinder head 9, a cylinder block 10, and a piston 11, and the exhaust gas generated by combustion of the air-fuel mixture is passed through an exhaust valve 15, an exhaust port 16, an exhaust branch pipe 17,
and is discharged to the atmosphere via the exhaust pipe 18. The bypass passage 21 connects the upstream side of the throttle valve 3 and the surge tank 4, and the bypass flow rate control valve 22 controls the flow cross-sectional area of the bypass passage 21 to maintain a constant engine rotational speed during idling. An exhaust gas recirculation (EGR) passage 23 that guides exhaust gas to the intake system in order to suppress the generation of nitrogen oxides connects the exhaust branch pipe 17 and the surge tank 4, and has an on-off valve type exhaust gas recirculation (EGR) passage. EGR) control valve 24 opens and closes EGR passage 23 in response to electric pulses.
The intake temperature sensor 28 is provided in the air flow meter 2 to detect the intake temperature, and the throttle position sensor 2
9 detects the opening degree of the throttle valve 3. Water temperature sensor 3
0 is attached to the cylinder block 10 to detect the cooling water temperature, that is, the engine temperature, and a well-known air-fuel ratio sensor 31 as an oxygen concentration sensor is attached to the collecting part of the exhaust branch pipe 17 to detect the oxygen concentration in the collecting part. The crank angle sensor 32 detects the crank angle of the crankshaft from the rotation of the shaft 34 of the power distributor 33 coupled to the crankshaft (not shown) of the engine body 7, and the vehicle speed sensor 35 detects the crank angle of the crankshaft from the rotation of the shaft 34 of the power distributor 33 coupled to the crankshaft (not shown) of the engine body 7.
Detects the rotation speed of the output shaft. The outputs of these sensors 2, 28, 29, 30, 31, 32, 35 and the voltage of the storage battery 37 are controlled by an electronic control unit 40.
sent to. A fuel injection valve 41 is provided near each intake port 5 in correspondence with each cylinder, and a pump 42 supplies fuel from a fuel tank 43 to the fuel injection valve 41 via a fuel passage 44. The electronic control unit 40 calculates the fuel injection amount using input signals from each sensor as parameters, and sends an electric pulse having a pulse width corresponding to the calculated fuel injection amount to the fuel injection valve 41.
The electronic control device 40 also controls the bypass flow control valve 2
2. Controls the EGR control valve 24, the solenoid 45 of the automatic transmission hydraulic control circuit, and the ignition device 46. The secondary side of the ignition coil of the ignition device 46 is connected to the control device 33 . The initialization set switch 48 is provided in the driver's cab or engine room, and when turned on manually, sends an initialization signal as an external signal to the electronic control device 40.

FIG. 2 is an internal block diagram of the electronic control unit. CPU (Central Processing Unit) 56, ROM (Read Only Memory) 57, RAM (Direct Access Memory) 58, Backup RAM 59, A/D (Analog/Digital) Converter with Multiplexer 6
0, and the input/output interface 61 is connected to the bus 6
They are connected to each other via 2. backup
The RAM 59 is connected to an auxiliary power source, and even when the ignition switch is opened and the engine is stopped, a predetermined amount of power is supplied to the RAM 59 so that the memory can be retained. Atrolog signals from the air flow meter 2, intake temperature sensor 28, water temperature sensor 30, storage battery 37, and air-fuel ratio sensor 31 are sent to the A/D converter 60. The outputs of the throttle position sensor 29, crank angle sensor 32, vehicle speed sensor 35, and initialization set switch 48 are sent to the input/output interface 61, and the bypass flow control valve 22,
EGR control valve 24, fuel injection valve 41, solenoid 45, and ignition device 46 receive input signals from input/output interface 61.

FIG. 3 is a flowchart of a program for changing the target idle rotational speed Nio. Step 6
In step 5, it is determined whether the initial set switch 48 is on or not, and if the determination result is positive, the process proceeds to step 66.
If not, exit this program.
In step 66, the current engine rotational speed Nn is set as the target idle rotational speed Nio and is stored in the backup RAM.
59. When changing the target idle rotation speed Nio, the adjuster increases or decreases the amount by which the accelerator pedal is depressed and adjusts the current engine rotation speed while watching the tachometer.
Adjust Nn. Instead of setting the current engine rotational speed Nn as the target idle rotational speed Nio, a knob is provided in the driver's cab or engine room to manually adjust the rotation amount, and the engine rotational speed represented by the rotation angle of the knob is set as the target idle rotational speed. May also be Nio.

The target idle rotation speed Nio is based on the engine operating condition,
For example, a plurality of target idle rotational speeds Nin can be stored in the backup RAM 59 depending on whether the air conditioner is on or not and whether the automatic transmission is in the drive range or the parking range. When the initial set switch 48 is switched from on to off, idle rotational speed control is performed based on the new Nio.

FIG. 4 is a flowchart of a program for selecting a target idle rotational speed from data in the ROM 57 or backup RAM 59. In step 70, it is determined whether the data in the backup RAM 59 is abnormal or clear.
If the determination result is positive, the process proceeds to step 71; if not, the process proceeds to step 72. Backup RAM59
It is necessary to back up whether the data is abnormal or not.
This can be detected using a parity check program built into the RAM 59 itself. Furthermore, when the storage battery 37 is removed for charging or replacement, the backup RAM 59 is in a clear state. In step 71, the data written as the target idle rotation speed in the mask ROM portion of the ROM 57 is selected as the target idle rotation speed Nio. At step 72, the data stored in the backup RAM 59 as the target rotational speed, that is, the data stored at step 66 described above, is selected as the target idle rotational speed Nio.

FIG. 5 is a flowchart of a program that adjusts the engine rotation speed during the idling period to the target idle rotation speed. In step 76, the target idle rotation speed Nio and the current engine rotation speed Nn are compared. In step 77, it is determined whether Nio≠Nn, and if the determination result is positive, the process proceeds to step 78, and if not, the process passes through (jumps) step 78.
In step 78, the bypass flow control valve 22 is operated to increase or decrease the flow cross-sectional area of the bypass passage 21.
If Nio>Nn, the flow cross-sectional area of the bypass passage 21 is increased to increase the intake air flow rate of the engine, and Nio<
If Nn, the flow cross-sectional area of the bypass passage 21 is reduced to reduce the intake air flow rate of the engine. The flow rate control valve 22 may be of a type that increases or decreases the degree of flow opening depending on the duty ratio of input pulses, or of a type that includes a step motor and changes the step position for each step by inputting pulses.

[Effects of the invention] As described above, according to the invention, the engine rotation speed set as the target idle rotation speed is stored in the storage device that can retain the memory even when the engine is stopped and the stored data can be changed, and the memory can be changed. is carried out by an external signal generated by the adjustment operator's operation. Therefore,
Appropriate idle rotational speed control can be performed by changing the predetermined rotational speed stored for read-only use or the engine rotational speed stored in the storage device.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of the entire electronic control engine to which the present invention is applied, Fig. 2 is a block diagram of the electronic control unit shown in Fig. 1, and Fig. 3 is a program for changing the target idle rotation speed of the backup RAM. FIG. 4 is a flowchart of a program for selecting a target idle rotational speed, and FIG. 5 is a flowchart of a program for adjusting the engine rotational speed to the target idle rotational speed. 3... Throttle valve, 5... Intake passage, 21... Bypass passage, 22... Flow rate control valve, 32... Crank angle sensor, 40... Electronic control device, 48... Initial set switch, 59... backup
RAM.

Claims (1)

[Claims for Utility Model Registration] 1. During the idling period, a predetermined rotational speed stored for read-only purposes is set as the target idle rotational speed and is arranged in parallel to the intake passage portion where the throttle valve is provided. An idle rotation speed control device for an electronically controlled internal combustion engine that controls an engine rotation speed by controlling an intake flow rate of a bypass passage, comprising: an external signal input means for inputting an external signal; when the external signal is input; a storage device that stores an engine rotational speed according to the external signal and retains the memory even during a period when engine operation is stopped; An idle rotation speed control device for an electronically controlled internal combustion engine, comprising: a target idle rotation speed switching means for setting the idle rotation speed as a target idle rotation speed. 2 Utility model registration claim 1, characterized in that the storage device is a backup RAM.
The idle rotation speed control device described in Section 1. 3. The idle rotation speed control device according to claim 1 or 2, wherein the engine rotation speed stored in the storage device is the engine rotation speed at the time when the external signal is generated. 4. The idle rotation speed control device according to claim 1 or 2, wherein the engine rotation speed stored in the storage device is set by a manually operated regulator. 5. characterized in that a plurality of engine rotational speeds are stored in the storage device in relation to the operating state of the engine;
An idle rotation speed control device according to any one of claims 1 to 4 of the utility model registration claims.