JPH0243905B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine rotation speed control device.

In general, there is a tendency to lower the idling speed of automobile engines in order to improve fuel efficiency or reduce exhaust gas. However, when considering variations in engine performance and changes over time, there is a limit to how much the idling speed can be reduced. Therefore, electronic control devices that accurately and stably control the idling speed over a long period of time have come into use.

FIG. 1 shows an example of a conventional device that uses a DC motor to control the idling speed by changing the stopper position of a throttle valve. In the figure,
1 is an ignition coil, 2 is an ignition coil control device, 3 is a period measurement circuit, 4 is a rotation speed calculation circuit, 5 is a target rotation speed calculation circuit, 6 is a deviation detection circuit, 7 is a control pulse width calculation circuit, 8 is a pulse 1 is a width counter, 9 is a control cycle counter, 10 is a control signal generation circuit, 11 is a drive circuit, 12 is a throttle valve drive device, 1
21 is a motor; 122 is a deceleration mechanism that converts the rotational motion of the DC motor 121 into linear motion; 123 is an idle switch that is turned on when the fully closed position of the accelerator pedal 14 is detected; and 124 is linearly driven by the deceleration mechanism 122. Throttle stopper, 12
5 is a cam mechanism interlocking with the throttle valve 13;
15 is a timer that operates in synchronization with the change of the idle switch 123 from OFF to ON and outputs a rotation speed control prohibition signal for a certain period of time; 16 is an idle determination unit that detects an idle state based on the output of the timer 15 and the output of the idle switch 123; Show the vessel.

Next, the operation of the above conventional device will be explained. first,
The period measuring circuit 3 is connected to the ignition coil 1 and measures the time interval between ignition signals generated by the ignition coil 1. The rotational speed calculation circuit 4 converts the time interval between the ignition signals into a rotational speed signal weighted by the rotational speed. The target rotational speed calculation circuit 5 calculates the target idling rotational speed and outputs the calculation result. The deviation detection circuit 6 compares the output signal of the rotation speed calculation circuit 4 and the output signal of the target rotation speed calculation circuit 5, and outputs the deviation as a rotation speed deviation signal to the control pulse width calculation circuit 7, and also outputs both output signals. A signal indicating the magnitude relationship between the two is output to the control pulse width calculation circuit 7 and the control signal generation circuit 10. The control pulse width calculation circuit 7 determines the optimum DC motor 12 according to the above two types of signals.
1 and outputs the calculation result to the pulse width counter 8. Here, the relationship between the rotational speed deviation signal, which is the input/output of the control pulse width calculation circuit 7, and the driving time of the DC motor 121 is shown in FIG. Second
In the figure, the horizontal axis shows the rotational speed deviation and the vertical axis shows the driving time. When the rotational speed deviation is within the dead band rotational speed region Nd, the driving time is zero and the DC motor 121 is not driven. The position does not change. Further, the area where the rotational speed deviation is to the right of zero corresponds to a region where the actual engine rotational speed is lower than the target idling rotational speed, and this region is
1 shows the relationship between rotational speed deviation and drive time when the throttle valve 13 is opened via the deceleration mechanism 122, throttle stopper 124, and cam mechanism 125 by rotating the throttle valve 1 normally. Furthermore, the area where the rotational speed deviation is to the left of zero corresponds to an area where the actual rotational speed is higher than the target idling rotational speed, and this area is where the DC motor 12
1 shows the relationship between the driving time and the rotational speed deviation when the throttle valve 13 is closed by reversing the rotation speed.

On the other hand, the control period counter 9
It is a counter that counts the period of intermittent driving of
An output signal is outputted to the pulse width counter 8 at regular intervals T shown in FIG. The pulse width counter 8 is composed of a preset counter, and at the same time as it presets the output value of the control pulse width calculation circuit 7 at the time when the control cycle counter 9 outputs the output signal, it starts subtraction at fixed time intervals, and the contents of the counter are This subtraction counting operation is continued until the count reaches zero, and the output signal is sent to the control signal generation circuit 10. The control signal generation circuit 10 determines the magnitude relationship between the target idling speed and the actual engine speed from the output signal of the deviation detection circuit 6, and when the actual engine speed is less than or equal to the target idling speed, the pulse width counter 8 Output terminal 1 with output signal as normal rotation signal
01, and if the idling speed is higher than the target idling speed, it is sent to the output terminal 102 as a reverse rotation signal. However, the control signal generation circuit 10 is connected to the idle switch 1.
23 is on, that is, the accelerator pedal 14 is fully closed, and the timer 15 does not output a rotation speed control prohibition signal, output is output to each output terminal 101, 102 according to the output of the idle discriminator 16, It is configured to perform idling rotation speed control. While the output signal is being generated at the output terminal 101, the drive circuit 11 sends a signal to cause the DC motor 121 to rotate in the normal direction, whereby the DC motor 121 rotates in the normal direction and the throttle stopper 124 is pushed out. The throttle valve 13 opens via the cam mechanism 125, and the engine rotation increases. Similarly, while the output signal is being generated at the output terminal 102, the DC motor 121 is rotated in reverse, and the throttle stopper 124 is retracted to stop the throttle valve 1.
3 moves in the closing direction and the engine rotation decreases.

Here, the operation until the engine speed becomes stable will be explained using FIG. 3. It is now assumed that the accelerator pedal 14 is in the fully closed position, the engine load increases before time _t1 , and the engine speed N is below the target idling speed _N0 . The rotational speed at time _t1 is _N1 , and the output value of the control pulse width calculation circuit 7 is _TP1 from FIG. Therefore, the pulse width counter 8 generates a signal for a time width TP ₁ from time t ₁ . Since this signal N ₀ >N ₁ , it is guided to the output terminal 101 of the control signal generating circuit 10 and output as a normal rotation signal as shown in FIG. 3a. As a result, the drive circuit 11 causes the DC motor 121 to rotate normally during the time interval _TP1 , the throttle valve 13 is opened, and the engine rotation increases. Next, the engine speed at time t ₂ after a certain period T from time t ₁ is
_N2 . At this point as well, since N ₀ >N ₂ , the DC motor 121 is rotated in the normal direction during the time interval TP ₂ in the same manner as described above, the throttle valve 13 is further opened, and the engine speed increases. As a result, the difference between the engine speed and the target idling speed _N0 falls within the dead zone Nd before reaching time _t3 , and
At _t3 , the DC motor 121 is not driven. Thereafter, the DC motor 121 will not be driven until the rotation speed deviation exceeds the dead zone Nd due to some disturbance.

Next, the operation during deceleration after racing will be explained using FIGS. 4 and 5. When the driver takes his foot off the accelerator pedal 14 at time _t10 from the acceleration state, the idle switch 123 is turned on from off, but the timer 15 outputs a rotation speed control prohibition signal for a certain period of time Td. Therefore, the idle discriminator 16 outputs a non-idle signal during the time Td even if the idle switch 123 is on, and no rotational speed control is performed. Therefore, if the time Td is longer than the completion of the deceleration state as _{shown in FIG} . Even if the rotation speed further decreases due to operation or an increase in electrical load, rotation speed control is not performed.
At time _t13 , when the timer 15 no longer outputs the rotation speed control prohibition signal, the idle discriminator 16 outputs an idle signal, and the rotation speed control is started. As a result, a raw rotation signal is output from the control signal generation circuit 10 in accordance with the difference between the target rotation speed N ₀ and the actual engine rotation speed N, and the throttle opening degree increases.
At time _t14 , the allowable rotational speed error range is reached.

Further, as shown in FIG. 5, if the engine speed before deceleration is high and the deceleration time is long, the idle switch 123 is turned from off to on for a time Td.
Even at the elapsed time _t21 , the engine rotation speed N does not decrease to near the target rotation speed _N0 . Therefore, a reversal signal is output from the control signal generation circuit 10, the throttle opening is closed from the opening corresponding to the engine load, and when the deceleration state is completed at time _t22 , the engine rotational speed N becomes even more than the target rotational speed _N0 . After that, the throttle opening is corrected by the forward rotation signal and converges to the target rotation speed N ₀ at time t ₂₃ .

As mentioned above, conventionally, rotation speed control during deceleration is prohibited for a predetermined period of time after the throttle opening reaches a predetermined value or less. There were problems such as prohibiting rotation speed control for a long time even after the deceleration state was completed, resulting in a delay in correcting load fluctuations, or conversely, starting speed control before the deceleration state was completed, resulting in a drop in engine speed. .

The present invention has been made in order to eliminate the above-mentioned conventional drawbacks, and detects the load condition of the engine and controls the prohibition time for starting rotation speed control during deceleration as a function of the load condition. It is an object of the present invention to provide an engine rotation speed control device that can start rotation speed control immediately after completion, has good responsiveness, and does not have a drop in rotation speed during deceleration.

Embodiments of the present invention will be described below with reference to the drawings.
In FIG. 6, 17 is a load detector that detects the engine load (for example, cooler on/off) during idling, and 18 is a predetermined time according to the output of the load detector 17 after the idle switch 123 changes from off to on. A timer 19 which prohibits the start of rotation speed control during Td is an idle discriminator which detects the idle state of the engine based on the output of the timer 18 and the output of the idle switch 123.

In the above device, operations other than during deceleration are the same as conventional ones, so the operation during deceleration will be explained using FIG. 7. First, it is assumed that the engine speed N is higher than the target idling speed _N0 at time _t30 . Here, the driver presses the access pedal 14.
When the driver releases his or her foot further and the accelerator pedal 14 and throttle valve 13 become idle, the idle switch 123 changes from off to on.
Also, the load detector 17 detects the engine load, and the timer 18 operates in response to the output of the idle switch 123, and when the cooler load as the engine load is on, the timer ₁₈ detects _the engine load.
Td Outputs a prohibition signal for _1- hour rotation speed control. or,
When the cooler load is off, the timer outputs a prohibition signal for controlling the rotation speed for Td ₂ hours from time _t30 to time _t32 . That is, when the engine load is heavy, the deceleration time is short, so the prohibition time for starting rotation speed control is shortened, and when the engine load is light, the deceleration time is long, so the prohibition time for starting rotation speed control is lengthened. The idle discriminator 19 receives the output of the idle switch 123 and the output of the timer 18, determines that it is in an idle state on the condition that the idle switch 123 is on and the timer 18 does not output a rotation speed control signal, and outputs an idle signal. . The control signal generating circuit 10 receives an idle signal from the idle discriminator 19, outputs a forward rotation signal or a reverse rotation signal, and starts rotation speed control. However, in the case of FIG. 7, the engine speed N has already converged near the target idling speed N0 at the time when the speed control is started, so the control signal generation circuit ₁₀ generates a forward rotation signal and a reverse rotation signal. is not output.

In the above embodiment, the timer 18 is activated when the throttle valve 13 becomes idle, but the timer 18 is used for deceleration determination to detect when the engine speed reaches a predetermined speed (greater than _N0 ). A rotation speed detector is provided separately, and the timer 18 is activated when the throttle valve 13 is in an idle state and the engine rotation speed falls below a predetermined rotation speed, thereby improving the start of rotation speed control. can be done.

Further, in the above embodiment, a throttle opening control type engine speed control device was described, but similar effects can be obtained with engine speed control devices of an air bypass control type, an ignition timing control type, an air-fuel ratio control type, etc. It will be done. Further, although the above embodiment uses a DC motor driven actuator, similar effects can be obtained by using a vacuum diaphragm type or current control type actuator.

As described above, the present invention is provided with a timer means that starts when the engine reaches an idle state and outputs a prohibition signal for controlling the rotation speed for a predetermined period of time depending on the magnitude of the engine load at that time. When the load is large and the deceleration time is short, the rotation speed control can be started earlier, and when the engine load is small and the deceleration time is long, the rotation speed control can be started later. Therefore, it is possible to obtain an engine rotation speed control device that does not start rotation speed control too early or too late, has good responsiveness, and does not have a drop in rotation speed during deceleration.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of a conventional device, Fig. 2 is an input/output characteristic diagram of control pulse width calculation circuits according to the conventional device and the present invention, Figs. 3 to 5 are timing charts showing the operation of the conventional device, and Fig. 6 is a configuration diagram of the device of the present invention,
FIG. 7 is a timing chart showing the operation of the device of the present invention. 4... Rotation speed calculation circuit, 5... Target rotation speed calculation circuit, 6... Deviation detection circuit, 7... Control pulse width calculation circuit, 8... Pulse width counter, 9... Control period counter, 10... Control signal generation circuit, 11
...Drive circuit, 12...Idle switch 123
Built-in throttle valve drive device, 13... Throttle valve, 14... Accelerator pedal, 17...
...Load detector, 18...Timer, 19...Idle discriminator. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A target engine rotation speed calculation means for calculating a target engine rotation speed, an engine rotation speed detection means for detecting the engine rotation speed, and an idle state detection means for detecting that the engine is in an idle state. , an engine rotation speed adjustment means for adjusting the engine rotation speed, an engine load detection means for detecting the engine load, and an engine load detection means that is activated when the engine reaches an idling state, and if the engine load at this point is large, the engine load is shortened and the engine load is small. timer means for outputting a prohibition signal for rotation speed control for a long predetermined time in some cases;
Control means for controlling the engine speed adjustment means in response to a difference signal between the output of the target engine speed calculation means and the output of the engine speed detection means on the condition that the timer means does not output a rotation speed control prohibition signal in an idle state. An engine speed control device comprising: 2. A rotation speed detector for determining deceleration is provided to detect when the engine rotation speed has reached a predetermined rotation speed, and the timer means detects when the throttle valve position is in an idle state and the engine rotation speed has fallen below the predetermined rotation speed. 2. The engine rotation speed control device according to claim 1, wherein the engine rotation speed control device is configured to start at a certain point in time.