JPH0415538Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Technical Field> The present invention relates to a fuel supply stop device that stops and restarts fuel supply to an internal combustion engine of a vehicle equipped with an automatic transmission, depending on the operating state of the engine.

<Background Art> The first example is an example of a combustion supply stop device and a transmission control device for an internal combustion engine of a vehicle equipped with an automatic transmission.
There is one shown in the figure.

The fuel supply stop device for this item is:
For example, there is a system disclosed in Japanese Unexamined Patent Publication No. 57-336, in which fuel is supplied to the engine when the throttle valve is fully closed (during idling), with the aim of improving the fuel efficiency and exhaust emissions of internal combustion engines installed in vehicles. The engine is stopped and restarted depending on the engine operating state detected by a group of sensors such as a rotation speed sensor and a water temperature sensor.

In other words, this fuel supply stop device is applied to internal combustion engines with cylinder-specific injection, and when the engine speed exceeds a set value determined from the water temperature in accordance with the throttle valve fully closed state, the fuel supply to the engine is stopped. stop. Then, when the engine speed drops below the set value R ₁ determined from the water temperature during this fuel supply stop, fuel supply to half of the cylinders is resumed, and when the engine speed decreases further, the same value is determined from the water temperature. The fuel supply to all cylinders is resumed when the set value _R2 becomes lower than the set value _R1 , which is smaller than the set value R1.
The fuel supply is restarted in stages to alleviate the shock given to the vehicle due to the sudden increase in torque when the fuel supply is restarted.

In addition, the engine speed during fuel supply stoppage
If the rate of decrease to R ₁ is large, the rotation speed will
Change the restart of fuel supply to half of the cylinders to restart fuel supply to all cylinders when R becomes less than ₁ to prevent the risk of engine stoppage due to engine speed undershoot caused by a sudden decrease in engine speed. It is something.

On the other hand, the transmission control device performs, for example, the following downshift control depending on the driving state of the vehicle and the operating state of the engine.

In other words, when the shift lever is in drive range 3rd gear, the vehicle speed is 30 to 50 km/hr, and the throttle valve is fully closed, when the brake is applied, it is determined that the vehicle is in deceleration mode, and the transmission is driven to shift from drive range 3rd gear. Shift down to drive range 2, then drive range 2 until re-accelerated.
maintain speed. In addition, efforts have been made to improve the effectiveness of engine braking when descending slopes, thereby reducing the burden of frequent brake and shift lever operations.

The fuel supply stop device for a vehicle equipped with such an automatic transmission control device operates as shown in FIG.

First, if the engine speed is equal to or higher than a predetermined value when the throttle valve is fully closed and the idle switch is turned on, fuel supply is stopped. When the brake is activated and all the conditions for downshift control are satisfied while the engine speed is decreasing due to the fuel supply being stopped, the downshift solenoid of the transmission is energized and the transmission is driven. automatically shifts down from drive range 3rd to drive range 2nd. Accordingly, the engine speed shifts from a decreasing process due to fuel supply stoppage to an increasing process due to an increase in the gear ratio due to downshifting. At this time, the transition to the process of increasing the engine speed is accompanied by a slight delay after the downshift solenoid is driven.

Here, when the minimum rotational speed within this delay period becomes equal to or less than the rotational speed _R1 set as a reference for restarting fuel supply, fuel supply is restarted. However, in this case, even if the fuel supply is not restarted, the engine speed will inevitably increase due to the downshift of the transmission, so restarting the fuel supply to increase the engine speed in this case is unnecessary. Become. Therefore, if a downshift is performed by the transmission control device during the fuel supply stop period, and the fuel supply is restarted immediately after that, an idle pseudo signal is output to the fuel supply stop device, and the fuel supply is forcibly stopped. The engine is stopped to improve fuel efficiency (see Japanese Unexamined Patent Publication No. 58-57048, etc.).

However, in this method, during the delay period from driving the downshift solenoid to increasing the engine speed, after the engine speed decreases to the speed R ₁ or less of the fuel supply restart condition and the fuel supply is actually restarted,
Since the idle pseudo signal is output to forcibly stop the fuel supply, unnecessary fuel is supplied during the period indicated by P in Figure 2, and fuel efficiency decreases by that amount. This was an inconvenience.

<Purpose of the invention> The present invention was made with attention to the above problem, and when downshift control is performed while fuel supply is stopped in a vehicle equipped with an automatic transmission control device, the engine rotation The present invention aims to improve fuel efficiency by providing a fuel supply stop device that does not restart fuel supply even if the number of fuels decreases temporarily.

<Summary of the invention> For this purpose, the present invention has a means for detecting the fully closed state of the throttle valve installed in the intake passage, a means for detecting the engine speed, and a means for detecting the fully closed state of the throttle valve installed in the intake passage, as shown in Fig. 3. means for stopping the fuel supply to the engine when the engine speed when the engine is closed becomes equal to or higher than a first set value, and the engine speed becomes smaller than the first set value while the fuel supply is stopped by the means; means for restarting the fuel supply when the fuel supply becomes equal to or less than a second set value; and means for detecting a predetermined deceleration driving state of the vehicle; and detecting the predetermined deceleration driving state of the vehicle by the means. A fuel supply stop device for an internal combustion engine for an automatic transmission equipped with a means for downshifting control so as to switch the gear ratio of an automatic transmission connected to the engine to a larger value when the predetermined deceleration operation is performed. Means for decreasing the second set value to a value smaller than the set value when the downshift control signal is not output for a predetermined period after the downshift control signal is output by the post-start downshift control means. A fuel supply stop device is constructed to achieve the above object.

<Example> The present invention will be described below based on an example shown in FIG.

Configuration Namely, a throttle sensor 1 detects the fully closed state of the throttle valve, a rotation speed sensor 2 detects the engine speed, an intake air sensor 3 that measures the intake air flow rate of the engine, and a temperature sensor of the engine cooling water. A water temperature sensor 4 is provided, and a vehicle speed sensor 5 that measures the speed of the vehicle as means for detecting the deceleration driving state of the vehicle, a brake switch 6 that detects the operation of the brake, and a shift switch 7 that detects the shift lever position are also provided. , these outputs are input to the microcomputer 8.

The microcomputer 8 includes a central processing unit (CPU) 8a, an input interface 8b, an output interface 8c, a ROM 8d, and a RAM 8e.
and a clock pulse oscillator 8f, which calculates the fuel injection pulse width corresponding to the operating condition based on the outputs of the sensor groups 1 to 4, and also determines whether or not to stop the fuel supply using the method described later. After the fuel supply has been completed, a determination is made as to when to restart the fuel supply, and a signal corresponding to the determination result is output to the drive circuit 9. This drive circuit 9 drives the injection valve 10 in response to a signal from the microcomputer 8, and as a result, fuel supply to the engine is stopped and restarted. That is, the microcomputer 8 and the drive circuit 9 constitute fuel supply stopping means and fuel supply restarting means.

Further, when the decelerating driving state of the vehicle is detected by the method described later from the outputs of the sensor groups 1, 5 to 7, which detect the decelerating driving state of the vehicle, the microcomputer 8 issues a downshift signal. When this signal is input to the downshift solenoid 11 for driving the transmission, the downshift solenoid 11 drives the transmission 12 so that the shift lever position is shifted down. That is, the microcomputer 8 and the downshift solenoid 11 constitute downshift control means.

Function Next, the function of this device will be explained according to the flowchart shown in FIGS. 5 and 6.

First, the subroutine for setting the timer flag shown in FIG. 5 will be explained. This subroutine is processed at regular intervals (for example, every 0.1 seconds). In S101, the outputs of throttle sensor 1, vehicle speed sensor 5, brake switch 6, and shift switch 7 are read, and in S102, the vehicle is It is determined whether or not the vehicle is in a deceleration driving state.

In other words, the throttle valve is fully closed and the vehicle speed is between 30 and 50.
Km/hr, and the brake is activated, it is determined that the vehicle is in deceleration driving mode. If the shift lever is in the third drive range at this time, the process advances to S103 and a downshift signal is sent. Next, S104
Go to and add 1 to the timer variable TC. Here, since this subroutine is processed every 0.1 seconds, an increase in the value of the timer variable TC by 1 corresponds to an increase of 0.1 seconds in the elapsed time since the start of the downshift signal. It is something.

Next, in S105, it is determined whether the value of the timer variable TC is greater than 20, and if the value of TC is less than 20, that is, 2 seconds have not elapsed since the start of the downshift signal transmission, the timer flag is set to 1 in S106. If the value of TC is 20 or more, that is, 2 seconds have elapsed since the start of the downshift signal, the timer flag is set to 0 in S107.

On the other hand, if it is determined in S102 that the vehicle is not in a decelerating driving state, the timer flag is set to 0 in S108, and the timer variable TC is cleared to zero in S109.

As is clear from the above, the fact that the timer flag set in this subroutine is 1 indicates that the elapsed time from the transmission of the downshift signal is less than 2 seconds.

The downshift signal sent in S103 is input to the downshift solenoid 11, and the transmission 12 is changed from drive range 3rd to drive range 2.
Drive downshift quickly.

Next, the main routine shown in FIG. 6 will be explained.

That is, in S1, the output signals of the sensors 1 to 4 that detect the engine operating state are read, and in S2, the fuel injection pulse width is calculated based on these signals. Then, in S3, it is determined whether or not the engine is being started, and if it is, in S4, the injection pulse width is corrected at the time of starting (fuel increase), and in S5, a time count with the contents described later is cleared. death,
In S6, a drive signal having the corrected injection pulse width is output to the injection valves of all cylinders, and fuel is supplied to all cylinders. That is, during an engine starting operation, fuel is injected into all cylinders regardless of other conditions in order to improve startability.

On the other hand, if it is determined in S3 that the engine is not being started, the process proceeds to S7, where it is determined whether or not the throttle valve is fully closed.If the throttle valve is not fully closed, the process proceeds to S6 via S5. A drive signal having the injection pulse width set in S2 is output, and fuel is supplied to all cylinders.

Further, when it is determined in S7 that the throttle valve is in the fully closed position, the process proceeds to S8, and it is determined whether the throttle valve continues to be fully closed. When the engine is fully closed for the first time in this calculation, that is, immediately after it is fully closed, the process proceeds to S9, where the engine speed N detected by the engine speed sensor 2 and the water temperature are determined as shown in the graph in Figure 7. Compare the corresponding predetermined rotation speed JC, and if N is less than JC, S5,
Proceed to S6, supply fuel to all cylinders, and if N is greater than or equal to JC, proceed to S10, clear the time count, and then S11
The drive of the injection valves of all cylinders is stopped and the fuel supply is stopped.

On the other hand, in S8, if the throttle valve was fully closed during the previous calculation, that is, if the fully closed state continues, the process advances to S12, and the engine speed N is determined in response to the water temperature as shown in the graph of Figure 7. The rotation speed BC is compared with the rotation speed BC which is larger than the JC set in advance. Then, if N is greater than or equal to BC, the process proceeds to S10 and after clearing the time count, fuel supply to all cylinders is stopped in S11, and if N is less than BC, the process proceeds to S13.

That is, in the process up to this point, if the engine speed N when the throttle valve is fully closed is greater than a set value determined by the operating state, fuel supply is stopped.

Next, in S13, it is determined whether or not the fuel supply is being stopped. If not, the process proceeds to S5 and S6 to continue supplying fuel to all cylinders, and if it is not, it is determined in S14.
Then, it is determined whether the rotational speed N is equal to JC. Then, if N and JC are equal, time counting is started in S15, and if not, the process directly proceeds to S16.

In S16, it is determined whether or not the value of the timer flag set in the subroutine is 1. If the timer flag is not 1, that is, before the downshift signal is transmitted or more than 2 seconds have elapsed after the downshift signal is transmitted. If so, proceed to S17 and compare the engine rotation speed N with the rotation speed R _{1 which} is smaller than the JC determined corresponding to the water temperature as shown in the graph of FIG. If N is greater than R1, the process proceeds to S11 to continue stopping the fuel supply, and if N is equal to _R1 , the time count that started from S15 is stopped in S18. In other words, the time T during which the engine speed N decreases from JC to _R1 is measured.

When this time T is smaller than a predetermined value _T1 , that is, when the rotational speed N suddenly decreases, the process advances from S19 to S5 and the time is counted to prevent the engine from stopping due to undershoot of the rotational speed N. After clearing, restart fuel supply at S6 and inject fuel in all cylinders. On the other hand, if the reduction time _T1 for the rotational speed N from JC to _R1 determined in S19 is greater, that is, if the reduction in the rotational speed N is slow, the process proceeds to S20 and fuel is supplied to half of the cylinders.

If N is smaller than _R1 in the determination in S17, the process proceeds to S23, where the rotational speed N is compared with a set rotational speed _R2 which is smaller than _R1 , which is set corresponding to the water temperature shown in FIG. If N is _R2 or more, the process proceeds to S20 to continue stopping fuel supply to half of the cylinders, and if N is less than _R2 , the process proceeds to S5 and S6 to supply fuel to all cylinders to prevent the engine from stopping.

On the other hand, if the timer flag is 1 in the determination in S16, that is, if it has been within 2 seconds since the downshift signal was sent, the process advances to S21, where the actual engine speed N and the set engine speed are determined in S17. R ₁
The comparison between the rotation speed N and the rotation speed R ₃ (see the graph in FIG. 7), which is set to a smaller value than the set rotation speed R ₁ , is changed. If N is greater than _R3 , the process proceeds to S11 and continues to stop fuel supply to all cylinders; if N is equal to _R3 , the time count that started from S15 is stopped in S18, and the value is set to a predetermined value in S19. Compared to _T1 , depending on the result, fuel is supplied to half of the cylinders in S20, or fuel is supplied to all cylinders in S6, which is the same as in the case of passing through S17.

When N is smaller than R ₃ in the judgment of S21,
Proceed to S24, where N is set to a value smaller than the set rotation speed R ₂ (refer to _the graph in Figure 7).
In comparison, when N is _R4 or more, the process proceeds to S20 and continues to stop fuel supply to half of the cylinders, and when N is less than _R4 , the process proceeds to S5 and S6 to supply fuel to all cylinders. .

In other words, for two seconds after it is determined that the vehicle is in the deceleration process during the fuel supply stop period and a downshift signal is issued, the set rotation speed, which is the standard for restarting fuel supply, is changed to a lower value and the fuel is The aim is to improve fuel efficiency by tightening the conditions for restarting supply. In this embodiment, the set rotation speed is changed to a low value for 2 seconds after the downshift signal is issued, but as is clear from FIG. The time is at least longer than the time required for the rotational speed to rise to a predetermined value, such as when the rotational speed reaches a maximum point.
That is, these steps S16, S21, and S24 correspond to the set value reduction correction means in FIG. Here, even if the fuel supply is not restarted, the engine speed will always increase due to the downshift, so there is no risk of the engine stopping.

The operating process at this time is shown in the time chart of FIG.

If the engine speed N when the throttle valve is fully closed is greater than the set speed JC, fuel supply is stopped from that point (indicated by A in the figure). Then, when the deceleration operation condition is satisfied and a downshift signal is issued in the process of reducing the engine speed due to this fuel supply stop, the timer flag is set to 1 for 2 seconds from this point (indicated by B in the figure). , the set rotational speed, which is a reference for resuming fuel supply, is changed from the set values R ₁ and R ₂ that would be applied when no downshift signal is issued to R ₃ and R ₄ that are set to smaller values.

For this reason, the minimum rotation speed within the delay period from when the downshift signal is issued until the transmission 12 is actually driven, the gear ratio increases, and the engine rotation speed rises becomes smaller than, for example, _R1 . However, since the reference rotational speed for restarting the fuel supply at this time is _R3 , which is smaller than _R1 , the fuel supply is not restarted. Then, the fuel supply (indicated by the dotted line in the figure) that would have been performed if the reference rotation speed for restarting fuel supply had not been changed is avoided, and fuel consumption is saved accordingly.

Further, if the minimum engine speed within the delay period becomes smaller than _R2 , if the minimum engine speed is larger than _R4 , fuel is supplied to half the cylinders,
If R is less than ₄ , fuel is supplied to all cylinders. Here, this reference value R ₄ is set smaller than the reference value R ₂ when the timer flag is not 1, so when R ₂ is used as the reference value, R ₄ is used as the reference value even if all cylinders are supplied with fuel. When this happens, there are many opportunities for fuel supply to remain in half of the cylinders, and fuel consumption is reduced accordingly. In this case as well, there is a significant increase in the rotational speed due to the downshift, so it is possible to sufficiently prevent the engine from stopping.

In this embodiment, the period for correcting the rotational speeds R ₁ and R ₂ , which serve as the reference for resuming fuel supply, was set within 2 seconds from the transmission of the downshift signal; however, this is not limited to this. The period may be set until the time when the rotational speed reaches a maximum value (the time indicated by C in FIG. 8).

Furthermore, although this embodiment is applied to a fuel supply system using a cylinder-specific injection method, if the fuel supply is not restarted in stages, the fuel injection system is equipped with one that performs fuel injection at one location on the upstream side of the manifold and a carburetor. The present invention can also be applied to objects, and the same effects can be achieved.

<Effects of the invention> As explained above, according to the invention, fuel supply is stopped in response to an increase in engine speed when the throttle valve is fully closed, and fuel supply is restarted in response to a decrease in engine speed, thereby reducing fuel consumption and improving exhaust emissions. During the fuel supply stop period by the supply stop device, if a deceleration driving state of the vehicle is detected and a downshift signal is issued to increase the gear ratio, a downshift signal is issued to change the set rotation speed that is the reference for restarting fuel supply. Since the value is corrected to a value smaller than the value when the engine is not in use, it is corrected to a value smaller than the value when the engine is not in use. Unnecessary resumption of fuel supply can be avoided, fuel consumption can be improved by extending the fuel supply stop period in a downshift state during deceleration, and the engine braking effect can also be improved.

[Brief explanation of drawings]

Figure 1 is a block diagram showing the configuration of a conventional example, Figure 2 is a block diagram showing the configuration of a conventional example.
The figure is a time chart showing the operating process of the same as above.
Figure 4 is a block diagram showing the configuration of the present invention, Figure 4 is a block diagram showing the hardware configuration of an embodiment of the invention, Figures 5 and 6 are flowcharts showing the operating process of the same, and Figure 7. 8 is a graph showing how to set the various setting values in the same as above, and FIG. 8 is a time chart showing the operation process in the same as above. DESCRIPTION OF SYMBOLS 1... Throttle sensor, 2... Rotation speed sensor, 5... Vehicle speed sensor, 6... Brake switch, 7... Shift switch, 8... Computer, 9... Drive circuit, 11... Downshift solenoid, 12...Transmission.

Claims (1)

[Scope of utility model registration request] means for detecting a fully closed state of a throttle valve disposed in an intake passage; means for detecting engine speed; means for stopping the fuel supply to the engine; and restarting the fuel supply when the engine speed becomes equal to or less than a second set value set smaller than the first set value while the fuel supply is stopped by the means. means for detecting a predetermined deceleration driving state of the vehicle; and switching the gear ratio of an automatic transmission connected to the engine to a larger value when the predetermined deceleration driving state of the vehicle is detected by the means. In the fuel supply stop device for an internal combustion engine for an automatic transmission equipped with a means for controlling a downshift, a predetermined period of time after the downshift control signal is output by the downshift control means after the start of the predetermined deceleration operation. , a fuel supply for an internal combustion engine for a vehicle with an automatic transmission, characterized in that a means is provided for decreasing the second set value to a smaller value than the set value when the downshift control signal is not output. Stop device.