JP3606384B2 - Engine fuel control device - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a fuel control device for an engine, and in particular, sets a deceleration fuel return rotational speed higher when an external load is on than when it is off, and decelerates when an elapsed time after the external load is on is short. Fuel control of the engine that prevents the external load from being adversely affected by keeping the external load on even while the engine is running, as well as preventing the return speed from falling to a low speed, thereby preventing deterioration of fuel consumption It relates to the device.
[0002]
[Prior art]
Techniques have been proposed for improving fuel efficiency by cutting fuel during deceleration.
In such a deceleration fuel cut engine, in view of the fact that the engine load increases when the external load is on, the fuel return speed is set higher than when the external load is off. (For example, Japanese Patent Publication No. 55-34295). By setting the return rotational speed to a higher value, the engine can be operated smoothly even when there is an engine load.
[0003]
[Problems to be solved by the invention]
If the load is turned on while the fuel is being cut, the stabilization of combustion is naturally impaired. Therefore, the fuel supply must be restarted with a higher return speed, but the load is turned on. When the return rotational speed is set to a higher value when the vehicle is in operation, the return of fuel supply is set earlier, and as a result, there is a drawback in that fuel efficiency deteriorates during deceleration.
[0004]
[Means for Solving the Problems]
The present invention has been proposed in order to eliminate the above-mentioned drawbacks of the prior art, and its purpose is to improve the fuel efficiency by preventing the return speed from becoming high by turning off the external load in principle during deceleration. On the other hand, when the external load is going to be turned off within a short period of time after the external load is turned on, the external load is prohibited from being turned off and the return rotational speed is kept low to prevent deterioration of fuel consumption. In addition, the present invention proposes an engine fuel control device that prevents adverse effects on external loads.
[0005]
The configuration of the present invention for this purpose is a fuel control device for an engine in which fuel is cut at the time of deceleration and the subsequent fuel return rotational speed is set higher than when the air conditioner is on compared to when it is off. ,
An air conditioner switch that switches the air conditioner on and off;
A load off means for stopping the operation of the air conditioner during fuel cut during deceleration;
An operating state detecting means for detecting an operating state of the air conditioner;
First determining means for determining whether or not a first predetermined time required for the refrigerant in the air conditioner to sufficiently cool has elapsed since the air conditioner switch was turned on;
When the fuel cut is performed while the air conditioner is in operation, the load off means determines that the elapsed time from when the air conditioner switch is turned on until the fuel cut is performed does not exceed the first predetermined time. The operation of the air conditioner is prohibited by the load off means only when the first predetermined time has elapsed since the operation stop of the air conditioner is prohibited .
[0006]
By prohibiting the operation of the air conditioner from being stopped , the fuel supply return rotation speed is kept low, so that deterioration of fuel consumption is prevented.
[0007]
【Example】
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a diagram showing an overall configuration of an engine fuel control apparatus according to an embodiment of the present invention. In the figure, a piston 2 slides in a combustion chamber 3 of the engine body 1, and an intake port 4 and an exhaust port 6 are supported by the combustion dead 3. An intake valve 7 is disposed between the intake port 4 and the combustion chamber 3, and an exhaust valve 8 is disposed between the exhaust port 6 and the combustion chamber 3.
[0008]
A throttle valve 9 for controlling the amount of intake air is provided on the upstream side of the intake port 4, and a surge tank 10 as an intake expansion chamber is provided on the downstream side thereof. Further, an injector 11 for supplying fuel to the wind turbine is provided downstream thereof. The amount of intake air to the intake port 4 is detected by a sensor 20 a in the air flow meter 20, and the temperature of the intake air is detected by a sensor 21. The throttle opening sensor 23 has a built-in idle switch 22 and detects the opening of the throttle valve 9. The distributor 15 is provided with a rotational speed sensor 25 for detecting the engine rotational speed, the intake port 6 is provided with an oxygen concentration sensor 26 and a catalyst device 24 is provided downstream thereof.
[0009]
The ECU 30 is connected to an air conditioner. A signal A / C in operation indicating that the air conditioner 100 is in operation is input. The ECU 30 can monitor the operating state of the air conditioner 100 with this signal. When a switch (not shown) of the air conditioner 100 is turned on, the air conditioner 100 normally operates, but the ECU 30 can stop or restart the operation of the air conditioner independently of the switch by the signal “A / C on”. .
[0010]
In the sail embodiment, an “air conditioner” is cited as an example of an external load, but this signal “A / C ON” is set to 0 in order to prevent the fuel supply return rotation speed from increasing and fuel consumption from deteriorating. The air conditioner 100 is stopped and “A / C ON” is set to 1 to restart the air conditioner 100.
In this embodiment, if the engine speed Ne exceeds NA (fuel cut speed) when the throttle is fully closed, the fuel supply is stopped. In this embodiment, two engine speeds for resuming fuel supply are prepared. As shown in FIG. 2, when the air conditioner 100 is on, the return speed is set to NRLON (<NA). When it is off, it is set to NRLOFF (<NRLON). The reason why NRLOFF <NRLON is that when the air conditioner is on, the fuel supply is restarted more quickly and does not adversely affect the air conditioner.
[0011]
3 to 5 are timing charts showing the operation of this embodiment. The outline of the control operation of the embodiment will be described with reference to these drawings.
FIG. 3 shows an operation when a fuel cut state (Ne> NA) is detected at time T1 when a sufficient time has elapsed since the air conditioner was turned on. In such a case, the air conditioner is stopped. By stopping the air conditioner, that is, by setting the fuel return rotational speed to NRLOFF when the load is off, improvement in fuel consumption is measured. Further, if the time from when the air conditioner is turned on until the refrigerant cools is t1, in the example of FIG. 3, since the air conditioner is turned on and t1 or more passes until the fuel cut occurs, the air conditioner is turned off at time T1. However, it will not adversely affect the air conditioner. By cutting the fuel supply, the engine speed decreases, and when Ne ≦ NRLOFF, the fuel supply is resumed (in the example of FIG. 3, time T2).
[0012]
FIG. 4 is a timing chart when time t2 elapses in the state (the throttle is fully closed and the air conditioner is stopped) after the air conditioner is stopped. That is, when the fuel supply is resumed at time T2 and the engine speed increases and Ne ≦ NA (time T3), the fuel cut is resumed. In this state, if the air-conditioner is off for a time t2 or longer, the refrigerant in the air-conditioner has warmed up, and the air-conditioner needs to be operated. Therefore, first, the fuel supply is restarted at time T4, and the air conditioner is operated about 1.2 seconds later. The reason for not restarting the fuel supply and operating the air conditioner at the same time is to prevent the occurrence of torque shock.
[0013]
FIG. 5 illustrates a case where the condition for stopping the fuel supply is established at the time when the refrigerant in the air conditioner is not sufficiently cooled (within time t1 after the air conditioner is turned on). In such a case, even if the conditions for stopping the fuel supply should be met and the air conditioner should be stopped, the air conditioner is not sufficiently cooled, so it is not possible for the driver to stop the air conditioner because hot air is blown out. Gives pleasure. Therefore, in this embodiment, the fuel supply is stopped and the air conditioner is not stopped, and the fuel supply return rotational speed is set to a higher NRLON. By setting the fuel supply return rotational speed to a higher NRLON, the engine rotational speed becomes too low to prevent adverse effects on the air conditioner. In this embodiment, a flag F is provided to indicate that the place where the air conditioner should be stopped is forcibly activated in order to cool the air conditioner. If time elapses in this state and the time t1 elapses after the air conditioner is turned on, it is considered that the refrigerant is sufficiently cooled, so the air conditioner is stopped (time T8).
[0014]
6 and 7 are flowcharts showing the control procedure of the embodiment. First, in step S2, the state of the idle switch, the engine speed Ne, and the like are read. In step S4, it is checked whether or not the throttle is in a fully closed deceleration state according to the state of the idle switch. When the engine is not in the idle state, the process proceeds to step S100, and appropriate control in that state is performed.
[0015]
When the engine is in the idle state, it is checked in step S6 whether the engine speed Ne exceeds the speed NA at which fuel cut is performed. When the engine speed Ne exceeds NA with the throttle fully closed, a fuel cut (F / C) is performed in step S8 in order to save fuel consumption.
In step S10, the operating state of the air conditioner is checked based on the signal “A / C operating”. Now, a case where the air conditioner is not operating will be described. In such a case, the process proceeds to step S24 to check the value of the flag F. Here, the flag F is
F = 0: Air-conditioner forced off F = 1: Normal air-conditioner off state F = 2: Air-conditioner cooling up. Accordingly, since the flag F is 1 when the air conditioner is turned off, the process proceeds from step S24 to step S26, the flag F is set to 1, and then the fuel supply return rotation speed is set to NRLOFF (<NA) in step S22. Set to. When the fuel supply return speed is set to NRLOFF, the fuel supply is resumed when the engine speed has dropped to NRLOFF.
[0016]
Next, consider a case where the air conditioner is turned on during fuel cut. In such a case, the process proceeds from step S10 to step S12. In step S12, it is checked whether an elapsed time since the air conditioner is turned on is longer than a predetermined time width t1. That is, it is checked whether the time t1 or more has elapsed since the air conditioner was turned on. If the air conditioner is turned on immediately before, t1 has not elapsed, so the process proceeds to step S14, and the fuel supply return rotational speed is set to NRLON (> NRLOFF). That is, before the time t1 has passed, since the refrigerant of the air conditioner has not cooled, the process proceeds to step S14 and subsequent steps, and the flag F is set to 2 to memorize that the air conditioner is “warming up”. Since the load increases by the amount of operation, the engine speed is increased from NRLOFF to NRLON to ensure engine stability. See FIG.
[0017]
If the engine speed Ne exceeds NRLON (<NA) before the time t1 has elapsed, NO is determined in step S6, and the process proceeds to step S40 (FIG. 6) → step S44 → step S46. Restart supply.
Next, the case where the fuel cut is performed while the air conditioner is operating (Ne ≧ NA and IDLE = 1) will be described. In such a case, the process proceeds from step S4 to step S6 to step S8 to cut the fuel, and the elapsed time until the air conditioner is turned on is checked in step S12. If the elapsed time does not exceed t1, as described above, the process proceeds to step S14 and thereafter. On the other hand, if the air conditioner has already been turned on at the time when the fuel cut is started and t1 hours have elapsed since it was turned on (FIGS. 3 and 4), the process proceeds from step S12 to step S18, and the air conditioner is turned off. To. Then, the flag F is set to 0 (step S20), and the fuel supply return rotational speed is set to NRLOFF lower than NRON in step S22. Since the refrigerant temperature has already decreased, there is no problem even if the air conditioner is turned off, and fuel consumption is improved by setting the fuel supply return rotation speed to NRLOFF lower than NRON. That is, when the engine speed Ne becomes less than the fuel cut speed NA, the process proceeds from step S6 to step S40 to step S42. If the engine speed Ne ≦ NRLOFF, the fuel supply is resumed in step S46 (FIGS. 3 and 4). Time T2).
[0018]
When the fuel supply is resumed, the engine speed may increase. The engine speed Ne may exceed NA.
A case where the fuel cut condition (Ne ≧ NA and IDLE = 1) is satisfied after the air conditioner is forcibly turned off and the flag F is set to 0 will be described. In such a case, the process proceeds from step S6 to step S8 to step S10. Since the air conditioner is forcibly turned off, the process proceeds from step S10 to step S24 to step S28. In step S28, the time elapsed since the air conditioner was forcibly turned off (step S18) is checked. If this elapsed time is less than t2, the refrigerant of the air conditioner is still cold. Therefore, the process proceeds from step S28 to step S22, the air conditioner is turned off, and the fuel supply return rotational speed is also kept at NRLOFF.
[0019]
After the air conditioner is forcibly turned off (step S18) and the flag F is set to 0 (step S20), more time has passed with the fuel cut condition (Ne ≧ NA and IDLE = 1) being satisfied. Explain the case. In such a case, the process proceeds in the order of step S6 → step S8 → step S10 → step S24 → step S28 → step S30. In step S30, the fuel supply is resumed (time T4 in FIG. 4). After a predetermined time (about 1.2 seconds) has elapsed in step S32, the air conditioner is restarted in step S34. When the time t2 or more has elapsed, it is considered that the refrigerant has warmed up considerably, so the air conditioner is restarted in step S34. The reason why the air conditioner is turned on after the fuel supply is resumed in step S30 is that the torque fluctuation due to resumption of fuel supply and the torque fluctuation due to ISC (idle speed control) accompanying the air conditioner on do not coincide.
[0020]
As described above, according to the fuel control device of this embodiment,
(1): Stops the fuel supply when decelerating and sets the return rotation of the subsequent fuel supply to a higher value than when the external load such as an air conditioner is off when the load is on. Occasionally, the excessive burden on the engine and external load is reduced.
(2): In principle, the external load is turned off during deceleration to reduce the load on the load, but the external load is not fully functioning. In some cases, that is, when the elapsed time since the load is turned on is not long (before t1 in the above embodiment), if a condition for stopping the fuel supply occurs, turn off the external load. Without activating it, it can be operated until the function can be fully exerted. Unless the external load is turned off, there is no problem even if the return speed of the fuel supply is set to a low value, so that deterioration of fuel consumption is prevented.
{Circle over (3)} In the above embodiment, the elapsed time for restarting the load after forcibly turning off the load is t2 (step S28). That is, if the state in which the load is forcibly turned off continues for t2 or longer, the load is in a state where it cannot perform its original function, so the forced off time is limited to t2 and the load is turned on again. It is.
(4): Although it is preferable to restart the fuel supply when the load is restarted, a torque shock may occur when the restart of the fuel supply coincides with the restart of the load. I try to do it as soon as possible.
[0021]
Obviously, the present invention is not limited to the above embodiments. For example, in the above-described embodiment, an air conditioner has been described as an example of the load. However, the present invention is not limited thereto, and can be applied to, for example, a vacuum pump in order to generate a negative pressure state.
[0022]
【The invention's effect】
Therefore, according to the fuel control device for an engine of the present invention, if a deceleration state in which the fuel supply should be stopped occurs in a state where the elapsed time after the external load is turned on is short, the external load is not stopped. Since this is not done, the return rotation speed of the fuel supply is kept low. Thus, adverse effects on external loads and deterioration of fuel consumption are prevented.
[Brief description of the drawings]
FIG. 1 is a diagram of an engine system according to a preferred embodiment to which the present invention is applied.
FIG. 2 is a diagram illustrating a fuel cut / return operation of the embodiment of FIG. 1;
FIG. 3 is a timing chart illustrating an example of the operation of the embodiment.
FIG. 4 is a timing chart for explaining an example of the operation of the embodiment.
FIG. 5 is a timing chart illustrating an example of the operation of the embodiment.
FIG. 6 is a flowchart illustrating a control procedure according to the embodiment.
FIG. 7 is a flowchart illustrating a control procedure according to the embodiment.

Claims (2)

In the fuel control device for the engine, which cuts the fuel when decelerating and sets the subsequent fuel return rotational speed higher when the air conditioner is on than when it is off,
An air conditioner switch that switches the air conditioner on and off;
Load off means for stopping the operation of the air conditioner during fuel cut during deceleration;
An operating state detecting means for detecting an operating state of the air conditioner;
First determining means for determining whether or not a first predetermined time required for the refrigerant in the air conditioner to sufficiently cool has elapsed since the air conditioner switch was turned on;
When the fuel cut is performed while the air conditioner is in operation, the load off means determines that the elapsed time from when the air conditioner switch is turned on until the fuel cut is performed does not exceed the first predetermined time. An engine fuel control device that prohibits air-conditioner operation stop and stops the air-conditioner operation by the load-off means only when the first predetermined time has elapsed . A second determination means for determining whether an elapsed time since the air conditioner is turned off by the load off means has passed a second predetermined time required for the refrigerant in the air conditioner to be warmed; The air conditioner operation stop by the load off means is set within the second predetermined time, and when the second predetermined time elapses during the fuel cut at the time of deceleration, the air conditioner is operated after returning the fuel. 2. The fuel control apparatus for an engine according to claim 1, wherein
.

Images