JPH01193052A - Idling engine speed control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To increase a generating capacity of a generator by increasing a target idling engine speed or a target opening of an intake air quantity adjusting valve during a period from lowering of voltage to rise of voltage in a battery. CONSTITUTION:A control part 9 detects a load based on respective signals from an air flow sensor 2 and an engine speed sensor 6 while, based on the load, respective openings of a target idling engine speed and an intake air quantity adjusting valve 12 are calculated. According to the calculated result, actuators 11 of a fuel injection valve 5 and the intake air quantity adjusting valve 12 are controlled, respectively. In this case, the control part 9 judges lowering of voltage and rise of voltage in a battery 10. During a period from lowering of voltage to rise of voltage in the battery 10, the target idling engine speed or the target opening of the intake air quantity are increased, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an idle speed control device for an internal combustion engine.

(Prior art) Fig. 1 shows the configuration of a conventional device, where l is an engine, 2 is an air flow sensor that detects the intake air amount of the engine 1, 3 is an intake pipe of the engine 1, and 4 is a sensor that detects the intake air amount of the intake pipe 3. a throttle valve to be adjusted; 5; a fuel injection valve for supplying fuel to the engine 1; 6;
1 is a rotation speed sensor that detects the rotation speed of the engine 1; 7 is an ignition device; 8 is a bypass passage that bypasses the throttle valve 4 and is connected to the intake pipe 3; 10 is a battery; 11 is an actuator;
Reference numeral 12 denotes an intake air amount adjusting valve that is driven by the actuator 11 and adjusts the intake air amount in the bypass passage 8 . Further, 9 is a control unit which receives the outputs of the intake air amount sensor 2, rotational speed sensor 6, and battery 10 and controls the fuel injection valve 5, ignition device 7, and actuator 11, and includes RAM 92 and ROM 93.
A microcomputer 91, an input circuit 94, and a
It consists of a /D converter 95 and an output circuit 96.

Next, a part of the operation of the above-mentioned conventional device will be explained with reference to the flowchart of FIG. In step 20, the control unit 9 detects the load from the outputs of the air flow sensor 2 and the engine rotation speed sensor 6, and calculates the target idle rotation speed T)III according to this load.

In step 21, the intake air amount adjusting valve 1 is also adjusted according to the load.
The target opening degree T of 2 is calculated. In step 22, a sensor (not shown) determines whether a closed-loop condition, that is, a condition without load fluctuation, is satisfied, for example, whether the throttle valve 4 is fully closed, etc., and if the closed-loop condition is satisfied, step In step 23, the target opening degree T3 of the intake air amount regulating valve 12 is corrected according to the deviation between the target idle rotation speed T and the actual idle rotation speed N, and in step 24, the actual opening degree is set to T. If the closed loop condition does not hold, the process directly proceeds to step 24.

[Problem to be solved by the invention]

However, in the conventional device described above, the target idle rotation speed TN is set to a low value in order to reduce fuel consumption, prevent vehicle body vibration, reduce noise, etc. As a result, the battery voltage decreases due to a decrease in the power generation capacity of the vehicle's power generator and an increase in the electrical load, and the battery voltage becomes below the minimum operating voltage of the electrical components, making it impossible to sustain no-load operation ( The engine stalled) or the starter failed to start, resulting in an inability to restart.

This invention was made in order to solve the above-mentioned problems, and it is possible to stably perform no-load operation and restart of the engine, and to minimize the adverse effects caused by the increase in rotation speed. The object of the present invention is to obtain an idle speed control device for an internal combustion engine that is capable of controlling the idle speed of an internal combustion engine.

[Means for Solving the Problems] An internal combustion engine idle speed control device according to the present invention includes:
A battery voltage determining means for determining whether the battery voltage has decreased or increased, and a means for increasing the target idle rotation speed or the target opening degree of the intake air amount regulating valve of the bypass passage from the time when the battery voltage is determined to have decreased to the time when it has been determined that the battery voltage has increased are provided. It is something that

[For production]

In this invention, the target idle rotation speed or the intake air Il of the bypass path during the period from when the battery voltage is determined to be low to when it is determined to be high. The target valve opening degree is increased, which increases the idle rotation speed, improves the power generation capacity of the generator, and increases the battery voltage.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. The configuration of the device according to this embodiment is the same as that in FIG. 1.
The operation of the apparatus will be explained with reference to flowcharts shown in FIGS. 3 to 5. In FIG. 3, in step 20, the target idle rotation speed TNe is calculated as in the conventional case. Step 2
In step 5, it is determined whether the voltage of the battery IO has decreased. This subroutine is shown in FIG.

In FIG. 4, in step 30, the battery voltage is
Since the normal output of the generator is 14v1 and the normal voltage of the battery 10 is 12V, the second predetermined voltage is set to 13.5V, for example.

If the voltage is less than the second predetermined voltage, a timer for a second predetermined time is preset in step 31, and the process proceeds to χ step 32. If the voltage is higher than the second predetermined voltage, proceed directly to step 32;
In step 32, it is determined whether or not the voltage is at least a first predetermined voltage (for example, 11■), and if it is above, a timer for a first predetermined time is preset in step 33, and the process proceeds to step 34.
If it is below the first predetermined voltage, the process directly proceeds to step 34. In step 34, it is determined whether the first predetermined time timer is O or not, and if it is 0, the state of below the first predetermined voltage is the first
This means that the battery voltage has continued for a predetermined period of time or more, and a battery voltage drop flag is set in step 35. In other cases, the process proceeds to step 36, and if the state of the second predetermined voltage or higher continues for a second predetermined time or more, the timer for the second predetermined time becomes 0, and the battery voltage drop flag is reset in step 37. . In step 3, the increase in the target idle speed by a predetermined value is reset, and in step 39, the increase in the target opening degree of the intake air amount regulating valve 12 by a predetermined value is reset.

In step 25, it is determined whether or not the battery voltage has decreased as described above, and if the battery voltage has decreased, the target idle rotation speed TN,
is increased by a predetermined value.

The subroutine shown in FIG. 5 gradually increases this predetermined value, and in step 40, if the gradual increase timer is 0, the gradual increase timer is preset in step 41, and in step 42, whether or not the opening degree is increased is less than the predetermined value. If it is below, ΔS is added in step 43. Step 44
Then, it is determined whether the increase in target rotation speed is less than or equal to a predetermined value.
If it is below, ΔN is added in step 45. In this way, the target opening degree and the target rotational speed are gradually increased by the predetermined values.

In step 21, a target opening T according to the load is calculated,
In step 27, it is determined again whether the battery voltage has decreased, and in step 28, the target opening degree Ts is increased by a predetermined value. This upload is also done gradually.

Thereafter, steps 22 to 24 are performed in the same manner as before.

In the above embodiment, the target idle rotation speed and the target opening degree of the intake air amount adjustment valve are increased from the time when the battery voltage is determined to be low to the time when it is determined to be high, so that the idle speed increases and the generator The power generation capacity of the battery improves and the battery voltage increases.

Therefore, idling operation and restartability can be improved. Further, when it is determined that the battery voltage has increased, the increase in the target value is stopped, and adverse effects such as increased fuel consumption can be suppressed. Furthermore, since the second predetermined voltage is made thicker than the first predetermined voltage, no chattering phenomenon occurs, and the increase in the target value is performed gradually.
The impact on the control system is alleviated.

In addition, in the above embodiment, both the target idle rotation speed and the target opening degree are increased when determining a decrease in battery voltage, but it is also possible to increase only one of them.

〔Effect of the invention〕

As described above, according to the present invention, the target idle rotation speed or the target opening degree of the intake air amount regulating valve in the bypass passage is increased from the time when the battery voltage is determined to be low to the time when the battery voltage is determined to be high. As the number increases, the power generation capacity of the generator increases, and the battery voltage increases. Therefore, idling operation and restartability can be improved. or,
When it is determined that the battery voltage has increased, the increase in the target value is stopped, and adverse effects such as increased fuel consumption can be suppressed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the apparatus of the present invention, FIG. 2 is a flowchart showing the operation of the conventional apparatus, and FIGS. 3 to 5 are flowcharts showing the operation of the apparatus of the invention. l...Engine, 2...Air flow sensor, 3...
・Intake pipe, 4... Throttle valve, 6... Rotation speed sensor, 8
... Bypass path, 9... Control unit, 10... Battery, 12... Intake air amount adjustment valve.

Claims (1)

[Claims] Setting the target idle speed of the engine or the target opening degree of the intake air amount regulating valve of the intake bypass passage according to the engine load,
In an internal combustion engine idle speed control device that controls the engine to achieve this set value, the battery voltage is
A decrease in the battery voltage is determined based on the fact that the battery voltage becomes equal to or less than a first predetermined voltage for more than a predetermined time, and that the battery voltage becomes equal to or greater than a second predetermined voltage that is greater than the first predetermined voltage for more than a second predetermined time. An internal combustion engine, characterized in that it is provided with a battery voltage determining means for determining whether the battery voltage has increased, and a means for increasing the target idle rotation speed or the target opening degree from the time when the battery voltage is determined to have decreased to the time when it has been determined that the battery voltage has increased. idle speed control device.