JP2004060547A - Vehicle power generation control device - Google Patents

Abstract

An object of the present invention is to prevent undershoot and overshoot of the engine speed after fuel cut.
A power generation by an alternator (4) is stopped or restricted prior to stopping supply of fuel to the engine or releasing the restriction. As a result, it is possible to avoid deterioration in fuel efficiency when the vehicle is decelerated.
[Selection] Fig. 2

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a power generation control device for a vehicle.
[0002]
[Prior art]
From the viewpoints of improving fuel efficiency and preventing the catalyst from being heated, so-called fuel cut, in which fuel supply to the engine is stopped or limited to a very small amount, is sometimes performed during vehicle deceleration.
[0003]
For example, Japanese Patent No. 2760037 discloses a technique in which when a signal indicating that fuel supply has been restarted after fuel cut has been detected, power generation of the charging generator is stopped or limited for a certain period of time thereafter.
[0004]
[Problems to be solved by the invention]
However, in the related art such as the above-mentioned Japanese Patent No. 27600037, even if a signal for forcibly stopping the power generation of the generator is transmitted after receiving the fuel cut recovery (fuel resumption) signal after the end of the fuel cut. Due to the signal transmission speed and the response delay of the generator, the power generation by the generator cannot be stopped or limited at the fuel cut recovery timing, and the undershoot of the engine speed cannot be effectively prevented. There is a fear.
[0005]
[Means for Solving the Problems]
Therefore, in the vehicle power generation control device of the present invention, a power generator driven by the engine to generate power, a fuel supply control means for stopping or restricting fuel supply to the engine under predetermined conditions, Generator control means for stopping or restricting the power generation by the generator prior to stopping the supply of fuel to the engine or releasing the restriction.
[0006]
【The invention's effect】
According to the present invention, the load on the generator is reliably reduced at the timing of stopping or stopping the fuel supply to the engine. Undershoot and overshoot of the engine speed can be effectively prevented.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
[0008]
FIG. 1 is an explanatory diagram schematically showing a system configuration of a power generation control device for a vehicle according to the present invention.
[0009]
The engine 1 is provided with a crank pulley 3 that rotates integrally with the crankshaft 2. A belt 6 is wound around the crank pulley 3 and an alternator pulley 5 attached to a rotating shaft of an alternator 4 as a generator. That is, the alternator 4 and the crankshaft 2 are configured to rotate synchronously.
[0010]
The alternator 4 has its power generation controlled by a command from an ECM (engine control module) 8 that monitors the voltage of a vehicle-mounted battery 7, and whether the generated power is charged in the battery 7. , And electric loads (LOAD) of the vehicle such as headlamps. When power is not generated by the alternator 4, electric power is supplied to the above-described electric load of the vehicle by discharging from the battery 7.
[0011]
Signals from a vehicle speed sensor 9 for detecting a vehicle speed and an engine speed sensor 10 for detecting the speed of the engine 1 are input to the ECM 8. Further, a lockup signal and a lockup release signal from a transmission of a vehicle having a lockup mechanism are input to the ECM 8. Here, the transmission of the vehicle equipped with the lock-up mechanism refers to any one of CVT (continuous continuously variable transmission), AT (automatic transmission), and MT (manual transmission). In addition, the ECM 8 controls the operation of the engine 1 based on a fuel injection command value determined according to the driving state of the vehicle so that optimal fuel injection is performed according to the driving state of the vehicle, When the vehicle is decelerated from a state where the engine speed is equal to or higher than a predetermined speed, so-called fuel cut control is performed in which fuel supply to the engine 1 is stopped or limited to a very small amount.
[0012]
Switching between fuel cut (stop or limit of fuel supply) and release of fuel cut in the fuel cut control is performed when the engine speed during vehicle deceleration drops to a predetermined fuel cut recovery speed.
[0013]
Further, the alternator 4 generates power during fuel cut, but the power generation is restricted before the fuel cut is released.
[0014]
More specifically, using the timing chart shown in FIG. 2, when the ECM 8 detects a lock-up release signal from the transmission of the vehicle during the fuel cut, the alternator 4 switches the alternator 4 at the timing when the lock-up release signal is detected. The ECM 8 controls the generated voltage from the normal generated voltage to a predetermined low generated voltage at once. The alternator 4 whose generated voltage is limited to a predetermined low generated voltage is controlled by the ECM 8 so that the generated voltage gradually increases from the timing when the fuel cut is released.
[0015]
Here, in the above-described first embodiment of the present invention, the flow of power generation control of the alternator 4 performed inside the ECM 8 will be described with reference to the flowchart of FIG.
[0016]
In step 11, the operation of the engine 1 is controlled based on a fuel injection command value stored in the ECM 8 in advance and determined according to the operating state of the vehicle.
[0017]
In step 12, it is determined whether or not the fuel is being cut. If the fuel is being cut, the process proceeds to step 13.
[0018]
In step 13, it is determined whether or not a lock-up release signal from a transmission having a lock-up mechanism is detected. When the lock-up release signal is detected, the process proceeds to step 14.
[0019]
In step 14, the power generation in the alternator 4 is restricted, the generated voltage of the alternator 4 is reduced to a predetermined low generated voltage at a stretch, and the process proceeds to step 15.
[0020]
Then, when it is determined in step 15 that the fuel cut has been released, the power generation restriction of the alternator 4 is released, and in step 16 the power generation voltage of the alternator 4 is gradually increased until it reaches the normal power generation voltage.
[0021]
In the power generation control device of the first embodiment, the power generation by the alternator 4 is limited based on the lock-up release signal of the transmission detected prior to the timing at which the fuel cut is released. Deterioration of fuel efficiency during deceleration can be avoided.
[0022]
Further, since the load of the alternator 4 on the engine 1 can be reduced at the timing of canceling the fuel cut, an undershoot or overshoot of the engine speed when the fuel cut is cancelled can be effectively prevented. As a result, the fuel economy can be improved by reducing the fuel cut recovery rotation speed.
[0023]
Then, by gradually increasing the generated voltage of the alternator 4 from the timing of canceling the fuel cut and returning to the normal generated voltage, it is possible to prevent a sudden change in the load fluctuation of the alternator 4 and to suppress the fluctuation in the rotation speed of the engine 1. be able to.
[0024]
Hereinafter, different embodiments of the present invention will be sequentially described. The system configuration of the power generation control device is substantially the same as that of the first embodiment described above (see FIG. 1).
[0025]
Next, a second embodiment of the present invention will be described. In the second embodiment, as shown in FIG. 4, the ECM 8 controls the alternator 4 to reduce the power generation voltage of the alternator 4 from the normal power generation voltage to a predetermined low power generation voltage at a timing when the lock-up release signal is detected. This is the same as the first embodiment described above, except that the generated voltage of the alternator 4 is thereafter limited to a predetermined low generated voltage for a predetermined fixed time, and after the predetermined fixed time has elapsed, Is controlled by the ECM 8 to return to the normal power generation voltage. It should be noted that the fuel cut is canceled during the predetermined period of time.
[0026]
Here, in the second embodiment, the flow of power generation control of the alternator 4 performed inside the ECM 8 will be described with reference to the flowchart of FIG.
[0027]
In step 21, the operation of the engine 1 is controlled based on the fuel injection command value which is stored in the ECM 8 in advance and is determined according to the driving state of the vehicle.
[0028]
In step 22, it is determined whether or not the fuel is currently being cut. If the fuel is being cut, the process proceeds to step 23.
[0029]
In step 23, it is determined whether or not a lock-up release signal from a transmission having a lock-up mechanism is detected. When the lock-up release signal is detected, the process proceeds to step 24.
[0030]
In step 24, the power generation in the alternator 4 is restricted, the generated voltage of the alternator 4 is reduced to a predetermined low generated voltage at a stretch, and the process proceeds to step 25.
[0031]
In step 25, it is determined whether or not a predetermined time has passed since the power generation in the alternator 4 was restricted in step 24. If the predetermined time has passed, the power generation of the alternator 4 is restricted. Then, in step 26, the power generation voltage of the alternator 4 is increased to a predetermined normal power generation voltage.
[0032]
Also in the second embodiment, similarly to the first embodiment, the alternator 4 generates power based on the transmission lock-up release signal detected prior to the timing at which the fuel cut is released. By restricting, it is possible to avoid deterioration in fuel efficiency when the vehicle is decelerated.
[0033]
Further, since the load of the alternator 4 on the engine 1 can be reduced at the timing of canceling the fuel cut, an undershoot or overshoot of the engine speed when the fuel cut is cancelled can be effectively prevented. As a result, the fuel economy can be improved by reducing the fuel cut recovery rotation speed.
[0034]
Next, a third embodiment of the present invention will be described. In the third embodiment, as shown in FIG. 6, when the engine speed decreases to a speed higher than the fuel-cut recovery speed by a predetermined speed (50 rpm), the power generation voltage of the alternator 4 is reduced to the normal power generation voltage. The alternator 4 is controlled by the ECM 8 so as to reduce the voltage to a predetermined low power generation voltage at once.
[0035]
The ECM 8 controls so that the generated voltage gradually increases from the timing when the fuel cut is released.
[0036]
Here, in the third embodiment, the flow of power generation control of the alternator 4 performed inside the ECM 8 will be described with reference to the flowchart of FIG.
[0037]
In step 31, the operation of the engine 1 is controlled based on a fuel injection command value stored in the ECM 8 in advance and determined according to the operating state of the vehicle.
[0038]
In step 32, it is determined whether or not the fuel is being cut. If the fuel is being cut, the process proceeds to step 33.
[0039]
At step 33, the engine speed is read, and the routine proceeds to step 34.
[0040]
In step 34, it is determined whether or not the current engine speed read in step 33 is smaller than a value obtained by adding 50 rpm to the fuel cut recovery engine speed. If it is smaller, the process proceeds to step 35, in which the alternator 4 generates power. Is performed, the generated voltage of the alternator 4 is reduced to a predetermined low generated voltage at a stretch, and the routine proceeds to step 36.
[0041]
Then, if it is determined in step 36 that the fuel cut has been released, the power generation restriction of the alternator 4 is released, and in step 37, the power generation voltage of the alternator 4 is gradually increased until it reaches the above-mentioned normal power generation voltage.
[0042]
In the third embodiment, at the timing when the engine rotation speed is reduced to a rotation speed higher than the fuel cut recovery rotation speed by a predetermined rotation speed, the power generation by the alternator 4 is limited, so that the fuel cut can be canceled. It is possible to limit the power generation of the alternator in advance, and it is possible to avoid deterioration in fuel efficiency when the vehicle is decelerated.
[0043]
Further, since the load of the alternator 4 on the engine 1 can be reduced at the timing of canceling the fuel cut, an undershoot or overshoot of the engine speed when the fuel cut is cancelled can be effectively prevented. As a result, the fuel economy can be improved by reducing the fuel cut recovery rotation speed.
[0044]
Then, by gradually increasing the generated voltage of the alternator 4 from the timing of canceling the fuel cut and returning to the normal generated voltage, it is possible to prevent a sudden change in the load fluctuation of the alternator 4 and to suppress the fluctuation in the rotation speed of the engine 1. be able to.
[0045]
Next, a fourth embodiment of the present invention will be described. In the fourth embodiment, as shown in FIG. 8, when the engine speed decreases to a speed higher by a predetermined speed than the fuel-cut recovery speed, the power generation voltage of the alternator 4 is reduced from the normal power generation voltage by a predetermined speed. The point that the alternator 4 is controlled by the ECM 8 so as to reduce the voltage to the low power generation voltage at once is the same as that of the third embodiment described above. It is controlled by the ECM 8 so that the generated voltage is returned to the above-mentioned normal generated voltage after a predetermined period of time.
[0046]
Here, in the fourth embodiment, the flow of power generation control of the alternator 4 performed inside the ECM 8 will be described with reference to the flowchart of FIG.
[0047]
In step 41, the operation of the engine 1 is controlled based on a fuel injection command value which is stored in the ECM 8 in advance and is determined according to the operation state of the vehicle.
[0048]
In step 42, it is determined whether or not the fuel is currently being cut. If the fuel is being cut, the process proceeds to step 43.
[0049]
At step 43, the engine speed is read, and the routine proceeds to step 44.
[0050]
In step 34, it is determined whether or not the current engine speed read in step 33 is smaller than a value obtained by adding 50 rpm to the fuel cut recovery engine speed. If it is smaller, the process proceeds to step 45, and the power generation by the alternator 4 is performed. Is performed, the generated voltage of the alternator 4 is reduced to a predetermined low generated voltage at a stretch, and the routine proceeds to step 46.
[0051]
In step 46, it is determined whether or not a predetermined time has passed since the power generation in the alternator 4 was restricted in step 45. If the predetermined time has passed, the power generation of the alternator 4 is restricted. Then, in step 47, the power generation voltage of the alternator 4 is increased to a predetermined normal power generation voltage.
[0052]
In the fourth embodiment, at the timing when the engine rotation speed is reduced to a rotation speed higher than the fuel cut recovery rotation speed by a predetermined rotation speed, the power generation by the alternator 4 is limited, so that the fuel cut can be canceled. It is possible to limit the power generation of the alternator in advance, and it is possible to avoid deterioration in fuel efficiency when the vehicle is decelerated.
[0053]
Further, since the load of the alternator 4 on the engine 1 can be reduced at the timing of canceling the fuel cut, an undershoot or overshoot of the engine speed when the fuel cut is cancelled can be effectively prevented. As a result, the fuel economy can be improved by reducing the fuel cut recovery rotation speed.
[0054]
In each of the above-described embodiments, the power generation voltage of the alternator 4 is reduced to a predetermined low power generation voltage before the timing of canceling the fuel cut. However, the power generation of the alternator 4 is stopped prior to the timing of canceling the fuel cut. (The generated voltage may be set to zero).
[0055]
In the first and third embodiments, the power generation voltage of the alternator 4 is gradually increased from the timing of canceling the fuel cut. However, the rate of increase of the power generation voltage at this time is reduced by the deceleration of the vehicle during the fuel cut. You may make it set according to a rate. More specifically, when the deceleration rate of the vehicle speed is large, the rate of increase of the generated voltage of the alternator 4 is small, and when the deceleration rate of the vehicle speed is small, the rate of increase of the generated voltage of the alternator 4 is set large.
[Brief description of the drawings]
FIG. 1 is an explanatory view schematically showing a system configuration of a power generation control device for a vehicle according to the present invention.
FIG. 2 is a timing chart according to the first embodiment of the present invention.
FIG. 3 is a flowchart according to the first embodiment of the present invention.
FIG. 4 is a timing chart according to a second embodiment of the present invention.
FIG. 5 is a flowchart according to a second embodiment of the present invention.
FIG. 6 is a timing chart according to a third embodiment of the present invention.
FIG. 7 is a flowchart according to a third embodiment of the present invention.
FIG. 8 is a timing chart according to a fourth embodiment of the present invention.
FIG. 9 is a flowchart relating to a fourth embodiment of the present invention.
[Explanation of symbols]
1: Engine 4: Alternator (generator)
8 ECM (fuel supply control means, alternator control means)

Claims (4)

A generator driven by an engine to generate power,
Fuel supply control means for stopping or limiting fuel supply to the engine under predetermined conditions,
A generator control unit for a vehicle, comprising: generator control means for stopping or restricting power generation by the generator before stopping or releasing the restriction of fuel supply to the engine by the fuel supply means. The fuel supply control means stops or restricts fuel supply to the engine during deceleration of the vehicle,
2. The vehicle according to claim 1, wherein the generator control means stops or restricts power generation by the generator when detecting a lockup release signal from a transmission of the vehicle equipped with a lockup mechanism. Power generation control device. The fuel supply control means stops or restricts the supply of fuel to the engine while the vehicle is decelerating, and sets a predetermined fuel cut recovery rotation when the fuel supply to the engine is stopped or restricted. When it drops to the number, the suspension or restriction of fuel supply to the engine is released,
2. The power generation control of a vehicle according to claim 1, wherein the generator control means stops or limits the power generation by the generator when the engine rotation speed becomes higher by a predetermined rotation speed than the fuel cut recovery rotation speed. apparatus. After the generator control means stops or restricts the power generation by the generator, the generator voltage of the generator is gradually reduced from the timing at which the fuel supply control means stops or restricts the fuel supply to the engine. The power generation control device for a vehicle according to claim 2 or 3, wherein:

Images