JPH03155397A - Control method for idle rotation variation - Google Patents

Abstract

PURPOSE:To limit the decreasing amount of a rotating speed by limiting the generating ratio of a generator if an electric load is abruptly increased when an engine is idling. CONSTITUTION:A regulator 10-3 alters the duty ratio of an exciting current flowing to a field coil FC in response to an electric load capacity. Thus, the current from a generator 10-1 is regulated. In other words, the duty ratio is increased for larger load current and decreased for smaller load current. The duty ratio of the exciting current is detected by an electronic controller 15. When the terminal G of the regulator 10-3 is grounded through a control unit 16 in response to a command from the controller 15, the exciting current flowing to the field coil FC becomes zero so that the generator current becomes zero, and generation is cut OFF.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is an engine that drives a generator using an internal combustion engine, and is designed to prevent unpleasant vibrations from occurring even when the electrical load suddenly increases during idling operation. The present invention relates to a rotation fluctuation control method.

The present invention is useful when applied to, for example, gasoline automobiles.

<Background Art> An automobile is equipped with an alternator that is rotated by the engine to generate electricity. While the engine is rotating, power generated by the alternator is supplied to various electrical loads, and the battery is charged with surplus power.

In an alternator, when a rotor having a field coil is rotated, three-phase alternating current is generated in a stator coil provided in a stator. The three-phase alternating current is rectified by a three-phase bridge rectifier formed of six diodes and output as direct current.

The voltage generated by the alternator is proportional to the rotational speed of the rotor and the magnitude of the excitation current flowing through the field coil. It is necessary to keep the voltage supplied to various electrical loads, such as charging the rechargeable batteries, constant, so when the rotation speed increases and the generated voltage is about to exceed the specified value, the excitation current is adjusted by the regulator to control the generated voltage. do.

The regulator adjusts the value of the excitation current flowing through the field coil of the alternator in accordance with the power supplied to various loads. In a transistor type regulator,
The amount of current is controlled by adjusting the duty ratio of the excitation current by turning on and off the power transistor.

In this way, by adjusting the excitation current value with the regulator, the voltage generated by the alternator is adjusted, thereby preventing overcharging or overdischarging of the battery.

The regulator B increases the excitation current sent to the alternator when the electrical load increases, and decreases the excitation current when the electrical load decreases. Therefore, the torque required to rotate the alternator increases when the electrical load is large, and decreases when the electrical load is small.

<Problem to be solved by the invention> By the way, when the electrical load suddenly increases while the car engine is idling, the excitation current flowing to the alternator increases, the torque that drives the alternator to rotate increases rapidly, and the rotational speed of the engine decreases. In some cases, engine rotation may become unstable and cause unpleasant vibrations to the driver.

During idling, the torque generated by the engine is small, and the above-mentioned problems are likely to occur, especially when the idling speed is set low for the purpose of reducing fuel consumption.

On the other hand, the driver does not perform any special operations while the vehicle is idling, and because the noise inside the car is low, he is more sensitive to engine noise and rotational fluctuations. In such a case, if you increase the electrical load by turning on a cooler or the like, the engine speed will drop, and this drop in engine speed will be clearly noticeable to the driver.

When the driver senses that the idle speed has decreased, he or she may feel uncomfortable and worried that the vehicle will stall. Furthermore, if engine vibration occurs, the feeling of anxiety and discomfort will increase.

In view of the above-mentioned prior art, the present invention provides an idle rotation fluctuation control method that limits the amount of drop in the rotational speed of an internal combustion engine even if the electrical load increases rapidly during idle operation.

Means for Solving the Problems〉 The method of the present invention for solving the above problems prevents the generator from rotating by limiting the power generation rate of the generator even if the electrical load suddenly increases while the engine is idling. This is to limit the torque required to cause the engine to rotate, thereby preventing the engine speed from dropping below a certain speed.

Effect: When the engine is running at idle, the power generation rate is limited even if the electrical load is large, so the engine speed will never fall below the preset allowable minimum speed. The minimum allowable engine speed is the engine speed that does not cause unpleasant vibrations felt by the driver even if the engine speed is reduced to this level.

Example of implementation Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 1 shows a drive system of a gasoline automobile to which the method of the present invention is applied. As shown in the figure, air is sent to the engine 1 via an air cleaner 2 and an air supply pipe 3. A throttle fp4 is installed in the middle of the air supply pipe 3.
The throttle valve 4 operates in conjunction with the accelerator pedal (not shown).
opens and closes. During idling, the throttle valve 4 is fully open, and the idle switch 5 detects this fully closed state (idling state). The bypass pipe 6 communicates the upstream side and the downstream side of the air supply pipe 3 so as to bypass the throttle valve 4 . A needle valve 8 biased by a compression coil spring 7 is provided in the bypass pipe 6, and the needle valve 8 opens and closes the bypass pipe 6 by driving the solenoid 9 on duty.

On the other hand, the alternator 10 is rotationally driven by the engine 1 to generate electricity, sends electricity to various electrical loads 11, and charges the battery 12 with surplus electricity. The battery 12 sends power to the electric load 11 when the power generated by the alternator is insufficient or when power is not generated.

The distributor 13 also has a crank angle sensor 14.
is provided.

The electronic control device 15 receives detection signals from various sensors such as the idle switch 5 and the crank angle sensor 14, and controls the solenoid 9 and various control devices. It also plays a central role in control when implementing the method of the present invention.

Here, the electrical system of the drive system shown in FIG. 1 will be explained with reference to FIG. 2. As shown in the figure, the alternator 10 is
A power generation section 10-1 having a stator coil SC and a field coil FC, and a rectifier 10- formed by a diode.
2 and a regulator 10-3 as the main components.

Among these, the regulator 10-3 changes the duty ratio of the excitation current flowing to the field fill FC according to the voltage of the battery 12 and the electric load capacity used, so that the current value generated by the power generation section 10-1 is changed. are being adjusted. In other words, when the battery voltage decreases or the electrical load capacity used increases, the duty ratio is increased to increase the generated current, and in the opposite situation, the duty ratio is lowered to decrease the generated current. ing. The duty ratio of the excitation current flowing through the field coil FC is detected by the electronic control unit 15 via the FR@. Further, according to a command from the electronic control device 15, the regulator 10
When the G terminal -3 is grounded through the control unit 16, the excitation current flowing through the field coil FC becomes zero, the generated current becomes zero, and power generation is cut off. Note that the regulator 10-3 adjusts the duty ratio according to the battery voltage and the electrical load capacity used.
There is also a type of regulator that adjusts the duty ratio based only on the electrical load capacity used without reference to the battery voltage.

In addition, in Fig. 2, 17 is an ignition switch,
18 is a charge lamp.

Next, the basic technology supporting the method of the present invention will be explained with reference to FIGS. 3 and 4.

FIG. 3 shows the relationship between the FR terminal duty and the G terminal grounding duty. FR terminal duty indicates the duty ratio of the excitation current detected at the FR terminal.
When the excitation current actually flowing through the field coil FC is continuous, the FR terminal duty is 100%, and when no excitation current is flowing through the field coil FC, the FR terminal duty is 0%. This FR terminal duty is proportional to the power generation rate of the alternator. The G terminal grounding duty indicates the rate at which the G terminal is grounded. If the G terminal is grounded continuously, the G terminal grounding duty will be 100%, and if the G terminal is not grounded at all, the G terminal grounding duty will be 100%. It becomes 0%.

When the G terminal is grounded as described above, the regulator 10
Regardless of the control status of -3, power generation is forcibly cut.

Figure 3 (a) shows the characteristics when the regulator 10-3 is generating 100% power, and as the G terminal grounding duty is lowered, the FR terminal duty (power generation rate) increases. I understand. Figure 3 (bl is the characteristic when the regulator 10-3 limits power generation to 50%, and even if the G terminal grounding duty is set to 50% or less, the FR
It can be seen that the terminal duty (power generation rate) does not fall below 50%. Figure 3 (cl is the characteristic when the regulator 10-3 limits power generation to 25%; even if the G terminal grounding duty is set to 75%, the FR terminal duty (power generation rate) is 75%. It turns out that it doesn't go beyond that.

From these facts, it can be concluded that the maximum value of the FR terminal duty (power generation rate) can be controlled by controlling the G terminal grounding duty.

Figure 4 shows the relationship between the FR terminal duty (power generation rate) and the drive torque required to rotate the alternator, and there is a one-to-one relationship between the rFR terminal duty (power generation rate) and the alternator drive torque. Obtain the following conclusion.

From the conclusions obtained from Figures 3 and 4, the following findings were found. In other words, when the electrical load increases, the regulator generally controls the power generation rate to increase, and as the power generation rate increases, the alternator drive torque increases (see Figure 4), which causes the engine speed to drop during idling, causing unpleasant vibrations. It causes So when idling,
If you limit the upper limit of the power generation rate using the G terminal grounding duty (see Figure 3) and limit the alternator drive torque, the engine speed will never drop below a certain speed (this way). This will prevent unpleasant vibrations from occurring.Also, by setting a strict limit value, even if the electrical load suddenly increases during idling, the driver will not notice that the engine speed has decreased. If the power generation rate is limited, there will be a shortage of electricity to meet the rapidly increasing electrical load, but this shortage will be covered by batteries.

Next, two embodiments of the idle rotation fluctuation control method of the present invention, in which the electronic control device 15 plays a central role in control, will be described.

First, a first embodiment of the present invention will be described with reference to FIG. 2 and FIG. 5, which is an operation flow diagram. A control map as shown in Table 1 below is preset in the electronic control unit 15.

Table 1 In Table 1 above, engine speeds N, ~N are engine speeds within the idle speed range, among which engine speed N is the lowest speed, N2. N.

..., the rotation speed increases, and the rotation speed N is the maximum rotation speed. The G terminal grounding duties -G, .about.G, are determined corresponding to each of the rotational speeds N, .about.N, respectively. Then, at each rotation speed N1 to N, if the G terminal grounding duty corresponding to the rotation speed is set to 〇1 to G, the FR terminal duty (power generation rate) will be adjusted according to the G terminal grounding duty. The upper limit is restricted so that the torque required to rotate the alternator will not exceed a certain value, and the control map will prevent the engine rotation speed from falling below a preset allowable minimum rotation speed. The "minimum allowable engine speed" here refers to the engine speed that does not cause vibrations that cause discomfort to the driver even if the engine speed drops to this level.
If the engine speed becomes lower than this allowable minimum speed, unpleasant vibrations will occur from the engine.

Therefore, if the electronic control device 15 controls the control unit 16 so that the G terminal grounding duty is set to G2 when the engine speed is N2, for example, the upper limit of the FR terminal duty (power generation rate) is limited. When the electrical load is small, the amount of power generation is controlled by the regulator 10-3 according to the electrical load.

However, even if the electrical load increases rapidly, the FR terminal duty
cannot exceed the upper limit defined by the G terminal grounding duty -G2. Therefore, even if the electrical load suddenly increases, the torque required to rotate the alternator will not exceed a certain value, and therefore the engine speed will not fall below the allowable minimum speed, causing unpleasant vibrations from the engine. does not occur.

Using the control map as described above, the electronic control device 1
5 performs the following control (see FIG. 5).

(1) First, the electronic control unit 15 determines whether the engine 1 is in idle operation (steps 1 and 2).

That is, when the idle switch 5 detects that the throttle valve 4 is closed and the crank angle sensor 14 detects that the crank angle is in the idling rotation range, it is determined that idling operation is being performed.

(2) When the engine is in idle operation, the electronic control unit 15 inputs the engine speed N at that time from the crank angle sensor 14 (step 3).

(3) Next, read the G terminal grounding duty -00~G, corresponding to the input engine speed N (N,~N) from the control map (step 4).

(4) The electronic control device 15 controls the control unit 16 to set the read G terminal grounding duty (one of G, to G) (Step 5). In this way, as described above, even if the electrical load suddenly increases, the engine speed will not fall below the allowable minimum speed, and unpleasant engine vibrations will not occur.

(5) After a certain timer count (step 6), the above-mentioned control is performed periodically.

(6) When the idle operation is stopped during the control, the electronic control device 15 stops the duty control of the control unit 16 and sets the G terminal ground duty to 0% (step 7).

Next, a second embodiment of the present invention will be described with reference to FIG. 2, FIG. 6 which is an operation flow diagram, and FIG. 7 which shows control characteristics. When controlling the second embodiment, the electronic control device 1
In Table 5, a control map as shown in Table 2 below is pre-prepared.
(Power generation rate) corresponding to each mode combining a to 100, G terminal grounding duty - G11. ...G... .

is set in advance. And in each mode,
If the set G terminal grounding duty is set, the engine speed will not fall below the allowable minimum speed even if the electrical load suddenly increases, and the engine speed fluctuation range will be within the preset allowable maximum speed. The control map is designed to keep the rotation within the rotational fluctuation range. The term "maximum permissible rotational speed fluctuation range" as used herein refers to a range of engine speed fluctuation within which even if the engine speed changes, the change will not be noticed by the driver.

FIG. 7 shows the relationship between two extracted parameters of the three-dimensional control map shown in Table 2. In other words,
Figure 7 (al) shows the relationship between the FRR child duty (power generation rate) and engine speed, Figure 7 (b) shows the relationship between the G terminal grounding duty and engine speed, and Figure 7 (al) shows the relationship between the G terminal grounding duty and engine speed. C) shows the relationship between the G terminal grounding duty and the FRR child grounding duty. Since the power generation capacity is small, the power generation rate is high (and as the engine speed increases, the power generation capacity increases, so the regulator automatically lowers the duty of the field current, lowering the power generation rate and keeping the power generation constant (electricity). In addition, as shown in Fig. 7(b), the FRR child duty (
Considering that the power generation rate is fixed, the G terminal grounding duty is
is the allowable rotational fluctuation range β for the current FRR child duty.
control to the value added by the amount. When converting the allowable rotational speed fluctuation width β into the G terminal grounding duty, the margin of the G terminal grounding duty is small because the engine output torque is small in the region of low engine speed, but as the engine speed increases, the engine output Since the torque also increases, the margin of the G terminal grounding duty can be increased. Further, as shown in FIG. 7 (cl), assuming that the engine speed is fixed, the G terminal grounding duty for the FRR child duty is set as a value that takes into account the allowable rotational fluctuation width β.

Therefore, for example, when the engine speed is N2 and the FR end terminal unity is al1, the G terminal grounding duty is set to G2. ,． 1, when the control unit 16 is controlled by the electronic control device 15, the upper limit of the FRR child duty (power generation rate) is limited. When the electrical load is small, the amount of power generation is controlled by the regulator 10-3 according to the electrical load. However, even if the electrical load increases rapidly,
FRR child duty is G terminal grounding duty-02”
It is not possible to exceed the upper limit defined by +1. Therefore, even if the electrical load suddenly increases, the torque required to rotate the alternator will not exceed a certain value, and therefore the engine speed will not fall below the minimum allowable speed, causing unpleasant noises from the engine. No vibration occurs.

Moreover, G terminal grounding duty - G2. Since al1 is a value that takes into account the allowable rotational speed fluctuation range, even if the electrical load increases rapidly, the engine rotational speed fluctuation range is small, and the driver will not notice this fluctuation.

Using the control map as described above, the electronic control device 1
Step 5: Perform the following control (see Figure 6).

(1) First, the electronic control unit 15 determines whether the engine 1 is in idle operation (steps 1 and 2).

That is, when the idle switch 5 detects that the throttle valve 4 is idle, and the crank angle sensor 14 detects that the crank angle is in the idle rotation range, it is determined that idle operation is being performed.

(2) When idling, the electronic I
The IJ control device 15 inputs the engine rotational speed N and FR@child duty at that time from the crank angle sensor 14 (step 3).

(3) Next, read the G terminal grounding duty corresponding to the input engine speed N and FR terminal duty mode from the control map (step 4).

(4) The electronic control device 15 controls the control unit 16 so that the read G terminal liquid ground duty is achieved (step 5). In this way, as mentioned above, even if the electrical load suddenly increases, the engine speed will not fall below the allowable minimum speed and unpleasant engine vibration will not occur, and the range of engine speed fluctuations will be the maximum allowable speed fluctuation. It settles within the range.

(5) After a certain timer count (step 6), the above-mentioned control is performed periodically.

] 6) If the idling operation stops during control, the electronic control system! ! 15 stops the density control of the control unit 16 and sets the G terminal grounding duty to 0% (step 7).

In the embodiments described above, the idle rotation fluctuation control method of the present invention was executed using the electronic control device 15, but the method of the present invention may be executed using a dedicated controller, in which case ζ is a dedicated controller. The controller may be built into the alternator. Further, the engine rotation speed may be determined by multiplying the alternator rotation speed by a required number.

<Effects of the Invention> As specifically explained above in conjunction with the embodiments, according to the present invention, even if the electrical load suddenly increases during idling operation, the upper limit of the power generation rate of the alternator is limited, so the alternator cannot be rotated. The torque required to do this will never exceed a certain value, so the engine speed will not drop much and the engine will not cause unpleasant vibrations.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram showing the gasoline automatic refresh drive system, Figure 2 is a circuit diagram showing the electrical system of a gasoline car, and Figure 3 is a FR
*Characteristic diagram showing the relationship between child duty and G terminal grounding duty, Figure 4 is a characteristic diagram showing the relationship between alternator drive torque and FR terminal duty, Figure 5 is the first embodiment of the present invention FIG. 6 is a flowchart showing the procedure of the second embodiment of the present invention, and FIG. 7 is a characteristic diagram showing the interrelationship of control parameters in the second embodiment. In the drawing, 1 is an engine, 5 is an idle switch, 10 is an alternator, 10-3 is a regulator, 11 is an electric load, 14 is a crank angle sensor, 15 is an electronic control device, and 16 is a control unit.

Claims (2)

[Claims] (1) It is rotatably driven to generate electricity, and is equipped with a power generation rate limiting means that can arbitrarily limit the upper limit of the power generation rate, which increases or decreases in response to increases and decreases in the electrical load, and the torque required for rotationally driving is adjusted to the power generation rate. A method for controlling idle rotation fluctuations of an engine of an engine having a generator having proportional characteristics and an engine that rotationally drives the generator, the method comprising reducing the engine rotation speed to a preset allowable minimum rotation speed. The power generation rate that leads to this is stored in advance in correspondence with each engine speed in the engine's idle speed range, and when the engine is running at idle, the engine speed is detected and the detected engine speed is An idle rotation fluctuation control method, characterized in that the power generation rate is limited by a power generation rate limiting means so that the power generation rate is set as an upper limit to a power generation rate stored in advance corresponding to the rotation speed. (2) It is rotatably driven to generate electricity, and is equipped with a power generation rate control means that can arbitrarily limit the upper limit of the power generation rate, which increases or decreases in response to increases and decreases in the electrical load, and the torque required for rotationally driving is adjusted to the power generation rate. A method for controlling idle rotation fluctuations of an engine of an engine having a generator having proportional characteristics and an engine that rotationally drives the generator, the method comprising reducing the engine rotation speed to a preset allowable minimum rotation speed. For each mode that combines each rotation speed and each power generation rate within the engine's idle rotation speed range, the power generation rate is determined so that the rotation speed fluctuation range is within the preset allowable maximum rotation speed fluctuation range without causing the engine speed to fall below the range. When the engine is idling, the engine speed and power generation rate are detected and the power generation rate stored in advance corresponding to the detected engine speed and power generation rate is set as the upper limit. An idle rotation fluctuation control method characterized in that the power generation rate is limited by a power generation rate limiting means.