JPH0363657B2 - - 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> An example of a fuel supply stop device and a transmission control device for an internal combustion engine of a vehicle equipped with an automatic transmission will be described with reference to FIG.

The fuel supply stop device for this item is:
For example, there is a method disclosed in Japanese Patent Application Laid-open No. 57-336, in which fuel is supplied to the engine when the throttle valve is fully closed (during idling) in order to improve the fuel efficiency and exhaust emissions of the internal combustion engine installed in a vehicle. It is stopped and restarted according to 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 stops fuel supply to the engine when the engine speed exceeds a set value determined from the water temperature depending on the throttle valve full state. Stop. During this fuel supply stop, when the engine speed drops below the set value R ₁ determined from the water temperature, fuel supply to half of the cylinders is restarted, and when the engine speed decreases further and the set value R 1 is determined from the water temperature. The fuel supply is restarted in stages by restarting fuel supply to all cylinders when the value _R2 becomes lower than the set value _R2 , which is smaller than R1. I am trying to ease the shocks given to me.

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 the following downshift control, for example, 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 hills, 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 vehicle is stopped to improve fuel efficiency.

However, in this case, during the delay period from driving the downshift solenoid to increasing the engine speed, after the engine speed decreases to the speed R ₁ which is 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 has been made with attention to the above-mentioned problems, and when a downshift is performed while the fuel supply is stopped in a vehicle equipped with an automatic transmission control device, the engine speed An object of the present invention is to provide a fuel supply stop device that does not restart fuel supply even if the fuel temperature temporarily decreases, thereby improving fuel efficiency.

<Summary of the Invention> For this purpose, the present invention includes 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, as shown in FIG. means for stopping the fuel supply to the engine when the engine speed at the time becomes equal to or higher than a first set value, and setting the engine speed to be 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; In a fuel supply stop device for an internal combustion engine for an automatic transmission equipped with a means for downshifting control so as to increase a gear ratio of an automatic transmission connected to the engine, the predetermined deceleration operation is started. means for measuring the number of times the engine speed shifts from a region larger than the second set value to a region smaller than the second set value; In order to achieve the above object, the fuel supply stop device is provided with a means for forcibly stopping the operation of the fuel supply re-means when the value shifts to the above value, and a means for starting the operation from the second time onwards.

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

The configuration includes a throttle sensor 1 that detects the fully closed state of the throttle valve, a rotation speed sensor 2 that detects the engine speed, an intake air amount sensor 3 that measures the intake air amount of the engine, and a temperature sensor that measures the temperature 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 state based on the outputs of the sensor groups 1 to 4, and determines whether or not to stop the fuel supply and restart the fuel supply using the method described later. The timing is determined and a signal corresponding to the 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, so that 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 a predetermined deceleration driving state of the vehicle is detected from the outputs of the sensor groups 1, 5 to 7 by a method described later, the microcomputer 8 issues a downshift signal. When the signal is input to the downshift solenoid 11, the downshift solenoid 11 shifts down the shift lever position of the transmission 12. That is, the microcomputer 8 and the downshift solenoid 11 constitute downshift control means.

Function Next, the function of this product will be explained according to the flowchart shown in FIG.

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 having the contents described later is cleared. , 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 the throttle valve is fully closed, and 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 fully closed state of the throttle valve is intermittent. When the engine is fully closed for the first time in this calculation, that is, immediately after it is fully closed, the process advances 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 of Figure 6. Compare the corresponding predetermined rotation speed JC, and if N is less than JC, S
5. Proceed to S6 to supply fuel to all cylinders, and if N is equal to or greater than JC, proceed to S10 and after clearing the time count, drive of the injection valves of all cylinders is stopped in S11 to stop fuel supply.

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 6. The rotation speed BC is compared with the rotation speed BC which is larger than the JC set in advance. If N is greater than or equal to BC, the process advances to S10 and after clearing the time count, fuel supply to all cylinders is stopped in S11, and if N is less than BC, S13
Proceed to.

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.

During this fuel supply stop period, sensors 1 and 5~
When a deceleration driving condition is detected by 7, that is, the throttle valve is fully closed, the vehicle speed is 30 to 50 km/hr, the brake is activated, and the shift lever position is in the 3rd drive range, a downshift signal is issued and the downshift is started. The solenoid 11 is energized, and the transmission 12 is downshifted from the third drive range to the second drive range.

Next, in S13, it is determined whether or not fuel supply is being stopped, and if not, S5 and S6
The process proceeds to S14 to continue supplying fuel to all cylinders, and if the engine is stopped, the process proceeds to S14 where it is determined whether the rotational speed N is equal to JC. Then, if N and JC are equal, S1
5 starts time counting, and if they are not equal, the process directly advances to S16.

In S16, the engine speed N is determined according to the water temperature as shown in the graph of FIG.
If N is larger than _R1 , the process proceeds to _S17 , where it is determined whether a downshift signal is being transmitted, that is, whether the vehicle is in a predetermined deceleration driving state. judge.

If the downshift signal is being transmitted, the process proceeds to S18, where the value of the flag F for transitioning from the fuel supply stop operation state to the fuel supply restart operation state during the deceleration operation period is set to zero, and S18 is set.
Proceed to step 11 to continue stopping fuel supply to all cylinders.

On the other hand, if it is determined in S17 that the downshift signal is not transmitted, S19
After resetting to 0 the counter C that measures the number of transitions from the fuel supply stop operation state to the fuel supply restart operation state during the deceleration operation period,
The process advances to S11 to continue stopping fuel supply to all cylinders.

If N is equal to _R1 in the determination in S16, the time count that started in S15 is stopped in S20, and the time required for the engine speed N to decrease from JC to _R1 is measured. Then, this time T is a predetermined value
When it is smaller than T ₁ , that is, when the rotational speed N suddenly decreases, in order to prevent the engine from stopping due to undershoot of the rotational speed N, proceed from S21 to S5, clear the time count, and then stop the fuel supply in S6. Restart and inject fuel on all cylinders. On the other hand, the time for the rotation speed N to decrease from JC to R ₁ determined in S21 is
When it is larger than T ₁ , that is, when the rotation speed N is slowly decreasing, the process advances to S22 and fuel is supplied to half of the cylinders.

If N is smaller than _R1 in the determination in S16, the process proceeds to S23, where it is determined whether or not a downshift signal has been transmitted, and if the downshift signal has not been started, the S
Proceed to step 24 and change the rotation speed N to a set rotation speed R ₂ which is smaller than R ₁ which is set corresponding to the water temperature shown in Figure 6.
In comparison, if N is R2 or _more , the process proceeds to S22 and fuel supply to half of the cylinders is restarted, 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 it is determined in S23 that a downshift signal is being issued, the process proceeds to S25 and it is determined whether the value of flag F is 0 or not. Then, if flag F is 0, that is, if entering a predetermined deceleration operating state was detected in the previous operating process of the program shown in this flowchart, the process advances to S26 and flag F is set to 1. At the same time, after adding 1 to the value of the counter C, the process advances to S27.

In other words, the fact that the flag F is reset from 0 to 1 in S25 and S26 indicates that the fuel supply stop operation state has transitioned to the fuel supply restart operation state in the predetermined deceleration operation state (while the downshift signal is being transmitted). The value of counter C indicates the number of times. The fact that the flag F is 1 also indicates that the state of N<R ₁ continues during the predetermined deceleration operation, and in this case, S
25, the process immediately advances to S27.

Step ST18, S of setting the value of this flag F
26 and the step S25 of determining the value of the flag F corresponds to the means shown in FIG. 3 for detecting the number of times the engine speed shifts to a second set value or less after the start of deceleration operation.

In S27, it is determined whether or not the value of the counter C is 1, that is, whether or not this is after the first fuel supply stop during the deceleration operation period. If the value of C is 1, the process advances to S11 and all Continue to stop fuel supply to cylinders. In other words, in this case, even if the engine speed N is smaller than R ₁ , which is the condition for restarting fuel supply to half of the cylinders, or even if N is smaller than R ₂ , which is the condition for restarting fuel supply to all cylinders. This is intended to improve fuel efficiency by forcibly stopping the resumption of fuel supply to all cylinders and avoiding fuel supply during the period indicated by P in FIG. 2, which was originally unnecessary. In other words, this step S27 corresponds to the fuel supply restart forced stop means shown in FIG. Here, even if the fuel supply is not restarted, the engine speed, which has once decreased, will increase by downshifting, so there is no risk of the engine stopping.

On the other hand, if it is determined in S27 that the value of the counter C is different from 1, the process advances to S24 and the engine speed N is
Proceeding to S22 or S5 depending on the magnitude relationship with R ₂ is the same as proceeding directly from S23 to S24.

The above operating process is shown in FIG. 7 using a time chart.

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 vehicle enters the predetermined deceleration driving state in the process of decreasing the engine speed due to the fuel supply stop, a downshift signal (indicated by B in the figure) is issued from that point onward.

The minimum rotational speed within the delay period from when this downshift signal is issued until the transmission 12 is actually driven, the gear ratio increases, and the rotational speed rises is _R1, which is the condition for resuming fuel supply to half of the cylinders. (or R ₂ which is the fuel supply restart condition for all cylinders), the counter value at this time is 1, so fuel supply is not restarted, and fuel efficiency is improved. Then, after the rotation speed increases due to the increase in the gear ratio, the rotation speed decreases again and the rotation speed increases.
When it becomes smaller than _R1 , the counter value is 2, so fuel supply is restarted and the engine is prevented from stopping.

This example is applied to a fuel supply system using a cylinder-specific injection method, but if fuel supply is not resumed in stages, it can be applied to a system in which fuel is injected at one location on the upstream side of the manifold or a system equipped with a carburetor. The present invention can also be applied to such devices, and the same effects can be achieved.

<Effects of the Invention> As explained above, the present invention provides a fuel system that reduces fuel consumption and improves exhaust emissions by stopping fuel supply in response to an increase in engine speed when the throttle valve is fully closed and restarting fuel supply in response to a decrease in engine speed. During the fuel supply stop period by the supply stop device, when the fuel supply restart condition is satisfied for the first time within the period when the deceleration driving state of the vehicle is detected and a downshift signal is issued to increase the gear ratio, By forcibly stopping the resumption of fuel supply, unnecessary resumption of fuel supply due to a temporary drop in engine speed during the period until the actual downshift is performed and the engine speed rises is avoided. This is intended to improve fuel efficiency.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a conventional example, Fig. 2 is a time chart showing the operating process of the same, Fig. 3 is a block diagram showing the configuration of the present invention, and Fig. 4 is a hardware configuration of an embodiment of the present invention. FIG. 5 is a flowchart showing the operating process of the above, FIG. 6 is a graph showing how to set various setting values in the above, and FIG. 7 is a time chart showing the operating process of the above. 1... Throttle sensor, 2... Rotation speed sensor, 5... Vehicle speed sensor, 6... Brake switch, 7... Shift switch, 8... Microcomputer, 9... Drive circuit, 11... Downshift solenoid , 12...transmission.

Claims (1)

[Claims] 1 A means for detecting the fully closed state of a throttle valve installed in an intake passage, a means for detecting the engine speed, and a means for detecting the engine speed when the engine speed is equal to or higher than a first set value when the throttle valve is fully closed. 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. and means for detecting a predetermined deceleration driving state of the vehicle, and increasing a gear ratio of an automatic transmission connected to the engine 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 a vehicle with an automatic transmission, the device includes a means for downshifting control, wherein the engine rotational speed is from a range larger than the second set value to a smaller range after starting the predetermined deceleration operation. a means for measuring the number of times the engine speed shifts to the second level based on a signal from the measuring means;
and means for forcibly stopping the operation of the fuel supply re-means when the value shifts to a value smaller than the set value, and restarting the operation from the second time onward. Supply stop device.