JP2010077836A - Idling speed determination device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an idle speed determination device changing the appropriate idle speed of an internal combustion engine based on the electric load of a vehicle including an auxiliary machine mounted to the vehicle and the state of an in-vehicle battery. <P>SOLUTION: The idle speed determination device 10 provided in an electrical system 100 of the vehicle includes an engine speed detection means 11 detecting the engine speed of the internal combustion engine, a power generation amount detection means 12 detecting the power generation amount of a generator, and a battery state detection means 13 detecting a differential voltage DVB between a voltage of the battery and a voltage of the generator. During the idle rotation of the internal combustion engine, if the maximum power generation amount in the idle speed is detected and a discharge volume Ah exceeding a predetermined volume is detected in the battery, the idle speed is increased to predetermined rotational speed so that the voltage of the generator conforms to the voltage of the battery based on the detected differential voltage DVB. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to control of a generator mounted on a vehicle that generates electric power by rotational driving of an internal combustion engine, and more specifically, based on the electric load of the vehicle including an auxiliary device mounted on the vehicle and the state of the on-vehicle battery. The present invention relates to a device for changing the idle speed of an internal combustion engine.

  A vehicle electrical system includes many electrical components such as an injector and crank sensor for engine system operation, lighting related to travel, switches, modulators, sensors, and other interior equipment. Many of these so-called auxiliary machines are electrically operated, and are electrically connected to a control device (hereinafter referred to as “ECU”) that controls an electric system of the vehicle. And the electric power for operating an auxiliary machine is supplied from the generator which generate | occur | produces by the rotation drive of an internal combustion engine, or the battery which is charging the generated electricity.

  The battery has a fixed charge capacity, and even if electricity flows in, the battery cannot be charged beyond this charge capacity. On the other hand, when the battery voltage is insufficient with respect to the charge capacity, it is necessary to supply electricity from the generator to the battery and charge it because there is a possibility that the electric power for operating the auxiliary machine may be insufficient. .

  The internal combustion engine during idling operation (in a state where the accelerator pedal is released during engine system operation) is operating at idle rotation at a low rotation speed. Since the idling speed has a low number of revolutions, the voltage generated by the generator during idling operation is low. If the battery voltage is insufficient at this time, there is a fear that the power for operating the auxiliary equipment is insufficient. For this reason, in such a case, measures such as setting the rotational speed of the internal combustion engine high have been taken.

  On the other hand, even if power is generated at a high idle rotation when the battery is sufficiently charged, the generated electricity cannot be charged and the fuel consumption of the internal combustion engine may be reduced.

Therefore, when the discharge current of the battery reaches a predetermined value during idling of the internal combustion engine, the idling speed is increased to increase the output voltage of the generator. On the other hand, when the discharge current does not reach the predetermined value There has been disclosed a technique for improving fuel efficiency without disturbing driving by maintaining a low idle speed (see, for example, Patent Document 1).
Japanese Utility Model Publication No. 61-10454

  Since the electrical load of the electrical system varies greatly depending on the operation status of the auxiliary machine, idle rotation corresponding to the load state is required. Also, from the start of the engine system until each part of the internal combustion engine reaches an appropriate temperature, the movement of each part of the internal combustion engine is not smooth, and idle rotation corresponding to this mechanical load state is also required. .

  However, since the above-described technique (Patent Document 1) determines the idle speed by comparing the discharge current of the battery with a predetermined value, it reflects the operating status of the auxiliary machine and the status of each part of the internal combustion engine. It is not a thing. Therefore, there is a possibility that the switched idling engine speed is not suitable for the temperature, season, etc. where the vehicle is placed.

  In such a situation, repeated charging / discharging of the battery deteriorates the battery and may not contribute to an improvement in fuel consumption of the engine system.

  In view of the above problems, the present invention provides an idle rotation speed determination device that changes a suitable idle rotation speed of an internal combustion engine based on an electric load of a vehicle including an auxiliary machine mounted on the vehicle and a state of an in-vehicle battery. The purpose is to do.

  In order to solve the above problems, an embodiment of the present invention includes a generator that generates electric power by rotational driving of an internal combustion engine, a battery that is arranged in parallel with the generator and charges the generated electricity, and the electric generator. An idle rotation speed determining device is provided in an electrical system of a vehicle including an auxiliary machine operated by electricity supplied from one or both of the machine and the battery.

  The idling engine speed determining device includes engine speed detecting means for detecting the engine speed of the internal combustion engine, power generation amount detecting means for detecting the power generation amount of the generator, voltage of the battery, voltage of the battery, and power generation. Battery state detection means for detecting a voltage difference from the machine voltage.

  Detected when the maximum power generation amount at the idling speed is detected at the idling speed of the internal combustion engine, and when the discharging amount exceeding the predetermined amount (the discharging state exceeding the predetermined time) is detected in the battery. Based on the difference voltage, the idling speed is increased to a predetermined speed so that the voltage of the generator matches the voltage of the battery.

  According to the above configuration, the difference voltage between the generator voltage and the battery voltage is used as an observation amount, and the electrical load as an electrical system of the entire vehicle including auxiliary equipment other than the engine system is used as the observation amount. Can do.

  That is, a change in the power consumed by the load of the auxiliary device mounted on the vehicle is detected by the difference between the voltage of the battery and the generated voltage of the generator. With this configuration, the power generation voltage of the generator and the voltage of the battery can be obtained as values including changes in characteristics due to the temperature of each engine.

  The control of the rotational speed of the internal combustion engine is often performed by the amount of intake air to the internal combustion engine. Compared to the conventional technology that controls the control amount of the intake air amount based on the control duty of the generator that is easily affected by the temperature of the engine, the correction term due to the effect of the engine temperature is eliminated. Even so, it is possible to perform control according to the situation. Further, by detecting the state of the battery, a sensor for detecting the current consumption of the vehicle that has been conventionally provided is not required, and thus the number of parts is not increased.

  The above-described embodiment may be configured as follows. That is, the generator is an AC generator having an excitation winding, and the power generation amount detecting means detects an excitation current flowing through the excitation winding and generates the power for a predetermined number of revolutions during idle rotation of the internal combustion engine. When the power generation amount of the machine does not exceed the maximum, or when the discharge amount of the battery is within a predetermined amount and the excitation current is higher than the predetermined value, the idle rotation speed may be increased to the predetermined rotation speed. Good.

  When the excitation current is determined to be high by the above-described configuration, the idle target rotational speed is increased, so that the influence of the generator torque can be reduced, so that a stable idle state can be maintained and the power generation efficiency is increased. be able to.

  The present invention can provide an idle rotational speed determination device that changes the rotational speed of a suitable internal combustion engine based on the electrical load of a vehicle including an auxiliary device mounted on the vehicle and the state of the on-vehicle battery.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration of an electrical system including an idle speed determination device according to the present embodiment, and FIG. 2 is a block diagram illustrating differences between a conventional electrical system and the electrical system according to the present embodiment. It is.

  The vehicle is equipped with a generator 30 called an alternator that generates electric power by the rotation of the internal combustion engine 20 of the engine system. While the internal combustion engine 20 is rotating, the electric power generated by the generator 30 is supplied to the electric load of the vehicle, and surplus electricity is charged in the battery 40.

  A vehicle's electrical load is a vehicle's electrical system. Many electrical components such as injectors, crank sensors, etc. related to engine system operation, lighting related to driving, switches, modulators, sensors, etc. Is applicable. These so-called auxiliary machines 50 are electrically connected to a control device (not shown; hereinafter referred to as “ECU”) that controls the vehicle electrical system.

  This embodiment is also the same, and as shown in FIG. 1, a generator 30 that generates electric power by rotating the internal combustion engine 20, and a battery 40 that is arranged in parallel with the generator 30 and charges the generated electricity. And an auxiliary machine 50 that is operated by electricity supplied from one or both of generated electricity and a battery.

  The electrical system 100 is provided with an idle speed determination device 10. The idle rotation speed determination device 10 includes a rotation speed detection unit 11 that detects the rotation speed of the internal combustion engine 20, a generator state detection unit 12 that detects the state of the generator 30, and a battery state detection that detects the state of the battery 40. Part 13.

  Here, the generator state detection unit 12 detects the amount of power generation, and the battery state detection unit 13 detects a difference voltage (DVB) between the voltage of the battery 40 and the voltage of the generator. In FIG. 2B, the battery state detection unit 13 is disposed on the minus terminal side of the battery 40, but may be disposed on the plus terminal side. The timer 14 will be described later.

  In the conventional electrical system 500 shown in FIG. 2A, the injector, the crank sensor, and the like, which are auxiliary machines 51 related to the engine system, are used as the “vehicle body electrical load” for detecting the power environment of the vehicle. And the electric current value sent to these auxiliary machines 51 was measured with the ammeter 15 as an observation amount. Therefore, there is a possibility that the electrical load of the entire vehicle cannot be grasped.

  Therefore, in the electrical system 100 of the present embodiment shown in FIG. 2B, the battery state detection unit 13 measures the difference voltage between the voltage of the generator 30 and the voltage of the battery 40 as an observation amount, and the engine system The electrical load (auxiliary machine 50) as the electrical system 100 of the entire vehicle including the auxiliary machine 52 other than the auxiliary machine 51 can be used as the observation amount.

  As described above, with this configuration, a change in electric power consumed by the load of the auxiliary device 50 mounted on the vehicle is detected by the difference between the voltage of the battery 40 and the generated voltage of the generator 30. Then, the power generation voltage of the generator 30 and the voltage of the battery 40 can be obtained as values including changes in characteristics due to the temperature of each engine.

  Next, a flow for changing the idle speed will be described with reference to the drawings. FIG. 3 is a flowchart of “target idle speed increase determination”, FIG. 4 is a flow chart of “target idle speed decrease determination”, and FIG. 5 is an idle state that combines determination of target idle speed increase and decrease. It is a flowchart for changing a rotation speed. Note that, in the reference numerals of the steps in the flowchart of FIG. 5, the same reference numerals are given to the steps common to FIG. 3 or FIG.

  First, with reference to FIG. 3, the determination of the target idle speed increase will be described. The idle rotation speed determination device 10 first acquires the power generation amount of the generator 30 from the detection result of the generator state detection unit 12. Then, it is determined whether or not the power generation amount is the maximum with respect to the current idling speed of the internal combustion engine 20 (step R01). The amount of power generation is determined by comparing the detected voltage with a preset maximum voltage during idling.

  When the maximum power generation amount, that is, when the detected voltage becomes the maximum voltage (step R01: YES), the generator voltage can only be changed downward, and no further power generation is possible. Therefore, the determination of the increase in the idle speed is continued, and the process proceeds to Step R02.

  Next, the idle speed determination device 10 determines from the detection result of the battery state detection unit 13 whether or not the battery 40 is discharged over a predetermined value in a predetermined time (step R02). Here, the predetermined value or more can be, for example, a discharge amount of −2 Ah or more. The discharge amount Ah is a product of the discharge current A and the discharge duration h until the discharge end voltage. This is because if the amount of discharge is large, the amount of charge of the battery 40 will be insufficient, and charging will be required.

  When the battery 40 is discharging more than a predetermined value in a predetermined time (step R02: YES), the idle speed determination device 10 determines the power generation voltage of the generator 30 detected from the battery state detection unit 13 and the battery 40. Based on the voltage difference (DVB) from the voltage, the target idle speed is increased so that the voltage of the generator 30 matches the voltage of the battery 40, and is changed to a predetermined speed (step R04).

  Here, the predetermined rotational speed differs depending on the vehicle, the engine mounted, and the environment. For example, the ascending side is set to about 700 rpm and the descending side is set to 600 to 650 rpm in advance. Not.

  The changed target idle speed is a predetermined speed that is increased from the current idle speed in order to charge the battery 40.

  When the amount of power generation is not the maximum, that is, when the detected voltage does not reach the maximum voltage (step R01: NO), and when the battery 40 has not discharged more than a predetermined value for a predetermined time (step R02: NO) The idle speed determination device 10 compares the excitation current with a predetermined value (step R03). Here, the predetermined value is a value at which the duty (power generation work amount) is 70 to 80%.

  If the excitation current is higher than the predetermined value (step R03: YES), the idle speed determination device 10 increases the target idle speed and changes it to a predetermined speed (step R04).

  In such a situation, it is assumed that the torque of the generator 30 is large, and the efficiency of power generation becomes low. In view of the influence of torque, the target idle speed is increased and changed to a predetermined speed.

  Note that when the exciting current is lower than the predetermined value (step R03: NO), the target idle speed is not changed.

  In such a configuration, when the power generation voltage of the generator 30 is lower than the voltage of the battery 40 and the discharge by the battery 40 alone continues, control is performed to increase the power generation capacity of the power generator 30 by increasing the idle target rotation speed. Therefore, excessive discharge of the battery 40 can be prevented, and consumption of the battery 40 can be reliably prevented.

  Furthermore, since the target idle speed is increased when the battery 40 is continuously discharged for a predetermined time, frequent switching of the target idle speed to the rising side can be prevented.

  When the exciting current is lower than the predetermined value, the target idle speed in the upward direction is changed, so that the influence of the torque of the generator 30 can be reduced. From this, it is possible to obtain an idling speed that maintains a stable idling state and increases power generation efficiency.

  Subsequently, with reference to FIG. 4, the target idle speed reduction determination will be described. The idle rotation speed determination device 10 first acquires the current flowing into the battery 40 from the detection result of the battery state detection unit 12. And it is judged whether this inflow current is rising rapidly (step D01). The sudden increase in inflow current is caused by a sudden decrease in the electrical load of the vehicle due to the operation of the auxiliary machine 50 being stopped.

  When it is determined that the inflow current has risen rapidly (step D01: YES), it is determined whether or not the difference voltage between the voltage of the battery 40 and the voltage of the generator 30 is small (step D02). When the differential voltage is small (step D02: YES), it is confirmed that the voltage has dropped and the electric load on the vehicle body is small. Then, the idle speed determination device 10 compares the excitation current with a predetermined value (step D03).

  If the excitation current is lower than the predetermined value (step D03: YES), the idle speed determination device 10 decreases the target idle speed and changes it to the predetermined speed (step D04). This is because it can be determined that the generator 30 is not working in such a situation.

  When there is no sudden increase in inflow current (step D01: NO), when the differential voltage is large (step D02: NO), or when the excitation current is higher than a predetermined value (step D03: NO) The target idle speed is not changed (step D05).

  With this configuration, it can be estimated that the load on the vehicle side is reduced. Then, it can be determined whether the internal combustion engine 20 is in an idling rotation state in which the power generation voltage of the generator 30 matches the voltage of the battery 40. In the present embodiment, the target idle speed in the downward direction is changed according to the situation, so that it is possible to provide information that contributes to improving fuel efficiency while maintaining a stable idle speed state.

  Next, with reference to FIG. 5, a flow for changing the idle speed that combines the determination of increase and decrease of the target idle speed will be described. In the reference numerals of the steps in the flowchart of FIG. 5, steps that are the same as those in FIG. 3 or FIG.

  As described above, the idle speed determination device 10 determines whether or not the power generation amount of the generator 30 is the maximum with respect to the current idle speed of the internal combustion engine 20 (step R01), and then the battery 40 Is discharged over a predetermined value for a predetermined time (step R02), and if both determinations are YES, the target idle speed in the upward direction is changed. However, if any determination is NO, the idle speed determination device 10 compares the excitation current with a predetermined value (step R03).

  In the determination of the target idle speed increase in FIG. 3, when step R03 is NO, the idle speed is maintained, but it is also expected that the electrical load of the vehicle is rapidly decreasing in such a situation. In addition, when the electrical load is suddenly reduced, the current flowing into the battery 40 rapidly increases, but the voltage of the battery 40 does not follow the increase in current and may cause a slight delay. In such a case, if the idling speed is maintained, the fuel consumption is deteriorated. Therefore, the flow is described later.

  When the excitation current is lower than the predetermined value (step R03: NO), the idle speed determination device 10 determines whether or not the current flowing into the battery 40 is rapidly increasing (step D01).

  When a sudden increase in current is first observed, there is a sufficient differential voltage (step D02: NO), or when it is determined that the excitation current is higher than a predetermined value (step D03: NO), the target idle rotation The number is not changed.

  However, the sudden increase in current is a result of a sudden decrease in electrical load, and it is expected that the electrical load of the entire vehicle thereafter will change. Therefore, a timer is set when the sudden increase in current is first observed (step T01), and then the target idle speed is determined again, and it is determined that the current flowing into the battery 40 does not increase rapidly. Even in the case (step D01: NO), it is determined whether the timer is operating.

  If the timer is operating (step T02: YES), the idle speed determination device 10 determines whether or not the difference voltage between the voltage of the battery 40 and the voltage of the generator 30 is small (step D02). The excitation current is compared with a predetermined value (step D03).

  When the differential voltage is small (step D02: YES), and when the excitation current is lower than a predetermined value (step D03: YES), the idle rotation speed determination device 10 decreases the target idle rotation speed and changes it to a predetermined rotation speed ( Step D04).

  As shown in FIG. 1, the timer 14 is one of the configurations of the idle speed determination device 10.

  With such a configuration, the current flowing into the battery 40 increases rapidly, but even when the voltage does not follow the increase in current, the timer 14 determines the differential voltage again, so that an appropriate idle speed is determined. be able to. Further, since the generated voltage is always fed back to the battery voltage, it is possible to prevent the battery from being repeatedly charged and discharged. And since the discharge current of a battery becomes small, the depth of charging / discharging becomes shallow and the deterioration of a battery can also be prevented.

  The preferred embodiments of the present invention have been described above. The present invention is not limited to the one described in the drawings, and design changes can be made without departing from the spirit of the present invention.

It is a block diagram which shows the structure of the electrical equipment system provided with the idle speed determination apparatus concerning one Embodiment of this invention. It is a block diagram which shows the difference between the conventional electrical equipment system and the electrical equipment system concerning this embodiment. FIG. 6 is a flowchart of “target idle speed increase determination”. It is a flowchart of "target idle speed fall determination". FIG. 5 is a flowchart for changing an idle speed that is determined by raising and lowering a target idle speed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Idle rotation speed determination apparatus 11 Rotation speed detection part 12 Generator state detection part 13 Battery state detection part 14 Timer 20 Internal combustion engine 30 Generator 40 Battery 50 Auxiliary machine 51 Engine system auxiliary machine 52 Other auxiliary machine

Claims (4)

A generator that generates electric power by rotational driving of an internal combustion engine, a battery that is arranged in parallel with the generator and that charges the generated electricity, and that is operated by electricity supplied from one or both of the generator and the battery An idle speed determination device provided in an electrical system of a vehicle equipped with an auxiliary machine,
A rotational speed detection means for detecting the rotational speed of the internal combustion engine;
A power generation amount detecting means for detecting a power generation amount of the generator;
Battery state detecting means for detecting a differential voltage between the voltage of the battery and the voltage of the generator,
When the internal combustion engine is idling, the maximum power generation amount at the idling speed is detected, and when a discharge amount exceeding a predetermined amount is detected in the battery, based on the detected differential voltage, An idle rotation speed determination device configured to increase an idle rotation speed to a predetermined rotation speed so that a voltage of a generator matches a voltage of the battery. The generator is an AC generator having an excitation winding,
The power generation amount detecting means detects an excitation current flowing through the excitation winding,
When the internal combustion engine is idling, the power generation amount of the generator with respect to a predetermined number of revolutions does not exceed the maximum, or when the discharge amount of the battery is within a predetermined amount and the excitation current is higher than a predetermined value, The idle rotation speed determination device according to claim 1, wherein the idle rotation speed determination device is configured to increase the idle rotation speed to a predetermined rotation speed. The battery state detection means detects an inflow current to the battery,
When the increase of the inflow current is greater than or equal to a predetermined value, the difference voltage is less than or equal to a predetermined value, and the excitation current is lower than the predetermined value, the idle rotation speed is decreased to a predetermined rotation speed, and the inflow current The idle speed determination device according to claim 2, wherein the idle speed determination device is configured to maintain the idle speed when the increase in the engine speed is equal to or less than a predetermined value. When the internal combustion engine is idling, the power generation amount of the generator with respect to a predetermined rotational speed does not exceed the maximum, or the discharge amount of the battery is within a predetermined amount, and the excitation current is lower than a predetermined value, And when it is determined that the increase of the inflow current is equal to or greater than a predetermined value, time measurement is started from the time when the determination is made and the idle rotation speed is maintained.
Thereafter, when the power generation amount of the generator does not exceed the maximum with respect to a predetermined rotation speed, or the discharge amount of the battery is within a predetermined amount, the excitation current is lower than a predetermined value, and the increase of the inflow current is When it is determined that the time is less than or equal to the predetermined time,
4. The idle rotation according to claim 3, wherein when the difference voltage is equal to or less than a predetermined value and the excitation current is determined to be lower than the predetermined value, the idle rotation speed is decreased to a predetermined rotation speed. Number determination device.

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