JP2006002603A - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize just enough torque correction of an internal combustion engine by grasping alternator load torque without directly detecting power generation current of an alternator. <P>SOLUTION: This control device for the internal combustion engine has the alternator 2 driven by the internal combustion engine, a battery 6 capable of charging electric power generated by the alternator 2, and a battery voltage sensor 7 (battery electric current sensor 8) for detecting whether or not the battery 6 is discharging. When the battery 6 is discharging, the alternator load torque generated in the alternator 2 serves as torque at the time of maximum power generation by the alternator 2, and torque correction of the internal combustion engine is performed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a control device for an internal combustion engine.

In Patent Document 1, the generated current of the alternator is detected by a current sensor, the alternator load torque generated in the alternator is calculated from the alternator generated current and the engine speed, and the opening of the auxiliary air control valve is determined according to the alternator load torque. What controlled this is disclosed. In Patent Document 1, since the alternator load torque is calculated using the alternator power generation current, the alternator load torque can be measured as the actual magnitude of the electric load. Therefore, by controlling the opening degree of the auxiliary air control valve according to the alternator load torque, the intake air amount can be controlled without excess or deficiency.
JP 2003-336532 A

  However, in Patent Document 1, a current sensor for directly detecting the generated current of the alternator is required, and there is a problem that the number of parts increases and the cost increases.

  An object of the present invention is to provide a control device for an internal combustion engine that realizes torque correction of the internal combustion engine without excess or deficiency by grasping the alternator load torque without directly detecting the generated current of the alternator.

  Therefore, the control device for an internal combustion engine of the present invention is characterized in that when the battery is discharged, the alternator load torque generated in the alternator is set as the torque at the time of maximum power generation of the alternator, and torque correction of the internal combustion engine is performed. .

  According to the present invention, when the battery is discharged, the electric load acting on the alternator is excessive, and the alternator is already generating power at its maximum capacity. The alternator load torque can be accurately estimated.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory view schematically showing a control device of an internal combustion engine (hereinafter referred to as an engine) 1 for an automobile.

  The alternator 2 is driven by the engine 1 by transmitting the rotation of a crank pulley 3 provided on a crankshaft (not shown) via an alternator drive belt 4 and an alternator pulley 5.

  The electric power generated by the alternator 2 can be charged to the battery 6 and can be directly supplied to a plurality of electric load configurations of the vehicle such as a headlight. Note that the power generation amount of the alternator 2 is controlled by an engine control unit 10 (described later) in accordance with the vehicle operating state. More specifically, for example, when the alternator 2 generates power during vehicle acceleration, the alternator load torque generated in the alternator 2 acts on the engine 1, so that power generation in the alternator 2 is prohibited and the alternator load torque is prohibited. Is cut.

  A battery 6 whose negative electrode (−electrode) is electrically connected to a large-capacity conductor such as a chassis of a vehicle includes a battery voltage sensor 7 capable of detecting a battery voltage (battery electromotive force), and a charge / discharge current of the battery 6. A battery current sensor 8 capable of detecting On the electric circuit, the battery current sensor 8 is disposed between the negative electrode of the battery 6 and a conductor having a large capacity. Further, the battery 6 can supply power to the electric load configuration by discharging.

  The plurality of electric load configurations are connected to the anode (+ electrode) of the battery 6. The plurality of electric load configurations generate an electric load by operating with electric power supplied from the alternator 2 and the battery 6.

  Among these electric load configurations, for a plurality of recognizable electric load configurations A, B, C,... That can recognize whether or not an electric load is generated, the operation signal is sent to the vehicle control unit 9. Have been entered. The vehicle control unit 9 indicates the operating status (whether it is operating or not operating) of the recognizable electric load configuration as vehicle load operating signal information via a so-called CAN (controller area network). (Hereinafter referred to as ECU) 10. Each electric load generated when these recognizable electric load configurations are operating is stored in advance in the ECU 10 as a predetermined current value, that is, a constant, and can be quantitatively grasped.

  The electrical load configuration includes a recognizable electrical load configuration capable of recognizing whether or not an electrical load is occurring, a non-recognizable electrical load configuration that does not recognize whether or not an electrical load is being generated, and In FIG. 1, only a recognizable electrical load configuration is shown for convenience. The non-recognizable electric load configuration is connected to the battery 6 and the alternator 2 in parallel with the recognizable electric load configuration on the electric circuit. In FIG. 1, three recognizable electrical load configurations A to C are described, but the number of recognizable electrical load configurations is not limited to three.

  As described above, the vehicle load operation signal information from the vehicle control unit 9 is input to the ECU 10, while the battery voltage sensor 7, the battery current sensor 8, the crank angle sensor 11 capable of measuring the engine speed, and the engine cooling A signal from a water temperature sensor 12 or the like that detects the water temperature is input. The opening degree of the electronically controlled throttle valve 13 disposed in the intake passage is controlled by a control signal from the ECU 10.

  When an electric load is generated in the electric load configuration and the alternator load torque is increased while the engine 1 is being driven, it is desirable to correct the engine torque according to the increase of the alternator load torque and generate an engine torque that is not excessive or insufficient. . The alternator load torque can be detected directly by installing an ammeter between the alternator 2 and the electric load configuration, but if the ammeter is installed between the alternator 2 and the electric load configuration, the parts The score will increase.

  Therefore, in the present embodiment, the alternator load torque is accurately estimated without directly detecting the alternator load torque, and the valve opening of the throttle valve is controlled so that the engine torque without excess or deficiency can be obtained, and the intake air amount The engine torque is corrected by changing. Specifically, when the alternator load torque increases, the intake air amount is relatively increased.

  The alternator load torque is a sum of current values during operation of the recognizable electrical load configuration (where an electrical load is generated) Is (hereinafter referred to as a recognizable electrical load configuration current total value) Is, The calculation can be performed based on the alternator power generation equivalent current S obtained by adding the base current Ib necessary for driving the engine and the charging current Ic to the battery 6. If the engine torque is corrected according to the alternator load torque, an engine torque with no excess or deficiency can be obtained.

  However, since there is a limit to the electrical load configuration that can recognize the operating status, it becomes overloaded when many non-cognitive electrical load configurations are operating, and this impedes drivability, such as rotation loss during idling. There is a possibility of causing.

  Therefore, in the present embodiment, in the state where power is being taken out from the battery 6 (battery is discharged), the electric load acting on the alternator 2 is excessive, and the alternator 2 has already generated power at its maximum capacity. Therefore, the engine torque is corrected with the alternator load torque as the torque at the time of maximum power generation of the alternator 2, that is, the alternator max torque.

  In a state where no power is taken out from the battery 6 (a state where the battery is not discharged), the alternator load torque is basically calculated based on the alternator power generation equivalent current S described above.

More specifically with reference to FIG. 2, for example, at the engine speed R0, the alternator power generation equivalent current S _R0 at this time is the recognizable electric load constituting current sum value Is _R0 , the base current Ib _R0, and the charging current Ic. _{Although it} can be grasped as the sum of _R0 , it does not necessarily match the actual generated current of the alternator 2 because it does not grasp the operating state of the non-cognitive electric load configuration.

Therefore, when the battery 6 is discharged even though the generator 2 is generating power, the alternator load torque at the engine speed _R0 is calculated using the alternator power generation equivalent current _SR0 . Instead, the alternator max torque at the engine speed R0 is used as the alternator load torque.

  The alternator max torque is determined by the alternator speed, the generated voltage of the alternator, and the temperature state of the alternator 2, but in this embodiment, as an alternative to these parameters, an alternator is used by using the engine speed, battery voltage, and engine water temperature. The maximum torque is calculated. The alternator speed is obtained by multiplying the engine speed by the pulley ratio between the crank pulley 3 and the alternator pulley 5.

  The alternator max torque is basically calculated by referring to the map shown in FIG. 3, but the alternator max torque also changes depending on the temperature state (operating state) of the alternator 2 itself, as shown in FIG. Furthermore, there is a characteristic that the temperature in the cold state becomes larger than that in the warm state.

  Therefore, in this embodiment, the battery voltage and the alternator rotational speed are used, the map reference value obtained by referring to the map of FIG. 3 is multiplied by the temperature correction coefficient corresponding to the temperature state of the alternator 2, and the alternator max. Torque is calculated. In this embodiment, if the engine water temperature is equal to or higher than a predetermined temperature set in advance, the alternator 2 is determined to be warmed up, and the value of the temperature correction coefficient is uniformly set to the predetermined value M. If the engine water temperature is lower than a preset predetermined temperature, the alternator 2 determines that the engine is cold, and the value of the temperature correction coefficient is uniformly set to the predetermined value N. The predetermined value M and the predetermined value N satisfy the predetermined value M <predetermined value N, and are determined for each alternator 2 model by experimental adaptation or the like and stored in the ECU 10 in advance.

  FIG. 5 is a flowchart showing the flow of control when calculating the alternator load torque.

  In S (hereinafter referred to as “step”) 1, it is determined whether or not the battery 6 is being discharged. If it is determined that the battery 6 is not discharged, the process proceeds to S 2, and if the battery 6 is being discharged, Proceed to S4. In the present embodiment, since both the battery voltage sensor 7 and the battery current sensor 8 are provided, the battery 6 is being discharged using the detected value of either the battery voltage sensor 7 or the battery current sensor 8. Determine if it is charging or not.

  In S2, the alternator power generation equivalent current S is calculated by adding the base current Ib and the charging current Ic to the recognizable electric load constituting current sum Is, and the process proceeds to S3.

  In S3, the alternator load torque is calculated from the alternator power generation equivalent current S. Specifically, the alternator power generation equivalent current S is converted into a torque reference map reference value using the map shown in FIG. 6, and the voltage correction coefficient is calculated using the battery voltage and the map shown in FIG. The alternator load torque is calculated by multiplying the corresponding map reference value and the voltage correction coefficient.

  In S4, it is determined whether or not the target power generation voltage of the alternator 2 is greater than or equal to a predetermined value T set in advance. If the target power generation voltage of the alternator 2 is greater than or equal to the predetermined value T, the process proceeds to S5. To S6. In other words, the target power generation voltage of the alternator 2 is compared by comparing the target power generation voltage of the alternator 2 controlled by the ECU 10 with the predetermined value T, which is the battery voltage when the battery 6 is sufficiently charged. If it is less than the predetermined value T, the process proceeds to S6, and if so, the process proceeds to S5.

  The amount of power generated by the alternator 2 is controlled by the ECU 10 in accordance with the operating state. For example, if the alternator 2 is generating power during vehicle acceleration, the alternator load torque generated in the alternator 2 acts on the engine 1 and accelerates. Feeling may get worse. On the other hand, the charge amount of the battery 6 can be estimated from the battery voltage, and if the power generation voltage of the alternator 2 is small with respect to the battery voltage, the battery 6 is discharged and power is supplied from the battery 6 to the electric load configuration. Therefore, the alternator load torque can be reduced.

  That is, this S4 is for determining whether or not the amount of charge of the battery 6 is sufficient at the time of transition in which an increase in engine torque is required. More specifically, for example, it is determined whether or not the charge amount of the battery 6 is sufficient during vehicle acceleration.

  In S5, the alternator load torque is set to the alternator max torque, the battery voltage and the alternator rotational speed are used, and the map reference value obtained by referring to the map of FIG. 3 described above corresponds to the temperature state of the alternator 2. The alternator max torque is calculated by multiplying by the temperature correction coefficient.

  In S6, the value obtained by subtracting a predetermined value set in advance from the previous value of the alternator load torque is compared with the magnitude relationship between 0 and the larger value is used as the current alternator load torque, and the battery 6 is being discharged. However, the alternator load torque is not set to the torque at the time of maximum power generation of the alternator.

  When the process proceeds from S4 to S6, the alternator load torque is set to 0 immediately, but even if the control of the alternator 2 is changed so that the alternator load torque becomes zero, the actual alternator load torque gradually becomes 0. Behaves like Therefore, in S6, the process of convergence toward 0 of the alternator load torque is regarded as max {(previous value of the alternator load torque−predetermined value), 0}, so that the alternator load torque is zero. In this way, the accuracy of the alternator load torque is improved.

  Therefore, this S6 substantially reduces the torque at the time of maximum power generation of the alternator 2 when the power generation voltage of the alternator 2 is made lower than the battery voltage by the ECU 10 and the battery 6 is in a discharged state. is there.

  As described above, in the present embodiment, when the battery 6 is discharged, the electric load acting on the alternator 2 is excessive, and the alternator 2 is already generating power at its maximum capacity. As a result, the alternator load torque for correcting the engine torque can be accurately estimated.

  Further, when the battery 6 is not discharged, the alternator load torque is calculated from the alternator power generation equivalent current S obtained by adding the base current Ib and the charging current Ic to the recognizable electric load constituting current sum value Is. The alternator load torque can be calculated with relatively high accuracy without directly detecting the alternator load torque.

  Then, by calculating the alternator max torque depending on whether the alternator 2 is in a warm-up state or a cold-down state, the engine torque can be corrected with higher accuracy.

  Further, when the power generation voltage of the alternator 2 is set lower than the battery voltage and the battery 6 is in a discharged state, the alternator load torque is controlled to be zero, so that the engine torque can be increased at a transient time. Good driving performance (for example, good acceleration performance) can be obtained.

  In the embodiment described above, both the battery voltage sensor 7 and the battery current sensor 8 are provided. However, in the case of a configuration having only the battery voltage sensor 7, the recognizable electric load configuration current sum Is is set to the engine. An alternator load torque may be calculated by adding the base current Ib necessary for driving as the alternator power generation equivalent current S.

  In this embodiment, the engine torque is corrected by changing the intake air amount according to the alternator load torque. However, the present invention changes only the intake air amount of the engine 1 according to the alternator load torque. For example, the ignition timing of the engine 1 is changed according to the alternator load torque, or the intake air amount of the engine 1 and the engine according to the alternator load torque are not limited thereto. Both of the ignition timing of 1 may be changed.

  The technical idea of the present invention that can be grasped from the above embodiment will be listed together with the effects thereof.

  (1) An alternator driven by an internal combustion engine, a battery capable of charging power generated by the alternator, and battery state detection means for detecting whether or not the battery is being discharged. If this is the case, the alternator load torque generated in the alternator is used as the torque during the maximum power generation of the alternator, and torque correction of the internal combustion engine is performed. As a result, when the battery is discharged, the electric load acting on the alternator is excessive, and the alternator is already generating power at its maximum capacity, so that the alternator load for correcting the engine torque Torque can be estimated accurately.

  (2) The control apparatus for an internal combustion engine according to (1) is specifically a current sensor in which the battery state detection means detects the charge / discharge current of the battery.

  (3) The control device for an internal combustion engine according to (1) is specifically a voltage sensor in which the battery state detection means detects the battery voltage.

  (4) The control device for an internal combustion engine according to the above (3) has power generation amount control means for controlling the power generation amount of the alternator according to the vehicle operating state, and the power generation amount control means controls the generated voltage of the alternator to the battery. In the case where the battery is in a discharged state by lowering the electromotive force, the torque generated in the alternator is not the torque at the time of maximum power generation of the alternator. As a result, it is possible to obtain good driving performance during a transient time when an increase in engine torque is required.

  (5) In the internal combustion engine control device according to (4), specifically, when the power generation voltage of the alternator is made lower than the electromotive force of the battery by the power generation amount control means, the battery is in a discharged state. The torque at the maximum power generation of the alternator is made zero.

  (6) In the control apparatus for an internal combustion engine according to any one of (3) to (5) above, among a plurality of electric load configurations of a vehicle that generates an electric load by operating with electric power supplied from an alternator and a battery When it is possible to recognize the electric load of a plurality of recognizable electric load configurations capable of recognizing whether or not the electric load is generated as a predetermined current value, and the recognizable electric load configuration is operating Has a current sensor that calculates the sum of the electric loads of the recognizable electric load configuration in operation as the total electric load configuration current value and detects the charge / discharge current of the battery. If not, an alternator obtained by adding the base current required for driving the engine, the recognizable electric load component current total value, and the charging current to the battery It calculates the alternator load torque based on the electrostatic equivalent current. Accordingly, the alternator load torque can be calculated with relatively high accuracy without directly detecting the alternator load torque.

  (7) In the control device for an internal combustion engine according to any one of (3) to (5) above, among a plurality of electric load configurations of a vehicle that generates an electric load by operating with electric power supplied from an alternator and a battery When it is possible to recognize the electric load of a plurality of recognizable electric load configurations capable of recognizing whether or not the electric load is generated as a predetermined current value, and the recognizable electric load configuration is operating Calculates the sum of the electrical loads of the perceivable electrical load configuration in operation as the perceivable electrical load current sum, and if the battery is not discharged, recognizes the base current required to drive the engine The alternator load torque is calculated based on the alternator power generation equivalent current obtained by adding the electric load constituent current sum value. Accordingly, the alternator load torque can be calculated with relatively high accuracy without directly detecting the alternator load torque.

  (8) The control device for an internal combustion engine according to any one of (1) and (3) to (7), further including an alternator rotation speed detection unit that detects the rotation speed of the alternator, and at the time of maximum power generation of the alternator. The torque is calculated from the battery voltage and the alternator speed.

  (9) The control device for an internal combustion engine according to (6) or (7), further including an alternator rotational speed detection means for detecting the rotational speed of the alternator, wherein the alternator power generation equivalent current is obtained by determining the battery voltage and the alternator rotational speed. Used to convert to alternator load torque.

  (10) The control device for an internal combustion engine according to any one of (1) to (9), further including an alternator operation state determination unit that determines whether the operation state of the alternator is a warm-up state or a cold-down state. Then, the torque at the time of maximum power generation of the alternator is calculated in consideration of the operation state of the alternator. The torque at the maximum power generation of the alternator is sensitive to the temperature of the alternator itself. As a result, the calculation accuracy of the torque at the time of maximum power generation of the alternator is improved, and the engine torque can be corrected more accurately.

  (11) Specifically, the control device for an internal combustion engine according to any one of (1) to (10) described above corrects the intake air amount of the internal combustion engine in accordance with the alternator load torque. Perform torque correction.

  (12) More specifically, the control device for an internal combustion engine described in (11) is corrected so that the intake air amount of the internal combustion engine is proportional to the alternator load torque.

BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which showed typically the control apparatus of the internal combustion engine which concerns on this invention. Explanatory drawing which showed typically the control content of the control apparatus of the internal combustion engine which concerns on this invention. The map figure used for calculating the alternator max torque. Explanatory drawing which shows the difference of the alternator max torque in a warm-up state and a cool-down state. The flowchart which shows the flow of the concrete control of the control apparatus of the internal combustion engine which concerns on this invention. The map figure used for converting the alternator power generation equivalent current S into a torque equivalent value. The map figure used for calculating a voltage correction coefficient using a battery voltage.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Alternator 6 ... Battery 7 ... Battery current sensor 8 ... Battery voltage sensor 10 ... Engine control unit (ECU)
13 ... Throttle valve

Claims (12)

An alternator driven by an internal combustion engine;
A battery capable of charging the power generated by the alternator;
Battery state detection means for detecting whether or not the battery is discharging,
A control apparatus for an internal combustion engine, wherein when the battery is discharged, an alternator load torque generated in the alternator is used as a torque at the time of maximum power generation of the alternator, and torque correction of the internal combustion engine is performed.   2. The control apparatus for an internal combustion engine according to claim 1, wherein the battery state detection means is a current sensor that detects a charge / discharge current of the battery.   2. The control apparatus for an internal combustion engine according to claim 1, wherein the battery state detection means is a voltage sensor that detects a battery voltage.   In the case where the power generation amount control means for controlling the power generation amount of the alternator according to the vehicle operating state is provided, and the power generation amount control means makes the power generation voltage of the alternator lower than the electromotive force of the battery so that the battery is discharged. 4. The control apparatus for an internal combustion engine according to claim 3, wherein the torque generated in the alternator is not the torque at the time of maximum power generation of the alternator.   5. The torque at the time of maximum power generation of the alternator is set to zero when the power generation amount control means makes the power generation voltage of the alternator lower than the electromotive force of the battery to discharge the battery. Control device for internal combustion engine. A plurality of recognizable electric load configurations capable of recognizing whether or not an electric load is generated among a plurality of electric load configurations of a vehicle that generates an electric load by being operated by electric power supplied from an alternator and a battery. Each electric load can be grasped as a predetermined current value, and when the recognizable electric load configuration is operating, the total of the electric loads of the operating recognizable electric load configuration can be recognized. It has a current sensor that calculates as a value and detects the charge / discharge current of the battery,
If the battery is not discharged, the alternator is based on the alternator power generation equivalent current obtained by adding the base current required for engine driving, the total value of the recognizable electrical load component current, and the charging current to the battery. 6. The control apparatus for an internal combustion engine according to claim 1, wherein load torque is calculated. A plurality of recognizable electric load configurations capable of recognizing whether or not an electric load is generated among a plurality of electric load configurations of a vehicle that generates an electric load by being operated by electric power supplied from an alternator and a battery. Each electric load can be grasped as a predetermined current value, and when the recognizable electric load configuration is operating, the total of the electric loads of the operating recognizable electric load configuration can be recognized. As a value,
When the battery is not discharged, the alternator load torque is calculated on the basis of the alternator power generation equivalent current obtained by adding the base current necessary for engine driving and the recognizable electric load constituent current sum value. The control device for an internal combustion engine according to any one of claims 1 and 3 to 5. An alternator rotation speed detection means for detecting the rotation speed of the alternator;
8. The control device for an internal combustion engine according to claim 1, wherein the torque at the time of maximum power generation of the alternator is calculated by a battery voltage and an alternator rotational speed. An alternator rotation speed detection means for detecting the rotation speed of the alternator;
The control device for an internal combustion engine according to claim 6 or 7, wherein the alternator power generation equivalent current is converted into an alternator load torque using a battery voltage and an alternator rotational speed.   It has an alternator operation state determination means for determining whether the operation state of the alternator is a warm-up state or a cold state, and the torque at the time of maximum power generation of the alternator is calculated taking into account the operation state of the alternator. The control device for an internal combustion engine according to any one of claims 1 to 9.   The control device for an internal combustion engine according to any one of claims 1 to 10, wherein torque correction of the internal combustion engine is performed by correcting an intake air amount of the internal combustion engine in accordance with an alternator load torque.   The control apparatus for an internal combustion engine according to claim 11, wherein the intake air amount of the internal combustion engine is corrected so as to be proportional to the alternator load torque.

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