JP2018115568A - Engine control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase an opportunity of idling stop control, in an engine control device which can perform the idling stop control of an engine.SOLUTION: An idling stop permission battery charging rate is set on the basis of a battery lowest voltage at a start of an engine, a battery temperature, and a battery charging rate correlated to a deterioration state of a battery, and when a current battery charging rate is higher than the idling stop permission battery charging rate, idling stop control is permitted. As above, an idling stop permission determination can be performed by using the further optimum idling stop permission battery charging rate which is added with a battery deterioration state by taking into consideration the battery charging rate at the start of the engine in addition to the battery lowest voltage at the start of the engine, and an opportunity of the idling stop control can be thereby increased.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an engine control device capable of executing engine idling stop control.

  In a vehicle equipped with an engine, for the purpose of reducing fuel consumption (fuel consumption rate), the engine is automatically stopped when a predetermined automatic stop condition is satisfied, and then the predetermined automatic restart condition is satisfied. A control (so-called idling stop control) is performed in which the starter is driven by power supply from the battery to automatically restart the engine.

  There exists a thing of patent document 1 as a technique regarding idling stop control. In the technique described in Patent Document 1 (hereinafter referred to as the conventional technique), the battery charge rate at the time of engine start is higher than the automatic stop permission battery charge rate threshold value set based on the lowest battery voltage at the time of engine start. When it is larger, automatic engine stop (idling stop control) is permitted.

JP 2013-024157 A

  By the way, in the above prior art, since the deterioration state of the battery is not taken into consideration, the automatic stop permission battery charge rate with a large battery charge rate with a sufficient margin for reliably starting (restarting) the engine. It is necessary to set a threshold value. For this reason, even when idling stop control can be executed, a situation in which idling stop control is prohibited occurs, and opportunities for idling stop control are reduced.

  The present invention has been made in view of such a situation, and an object of the present invention is to realize control capable of increasing the idling stop control in an engine control apparatus capable of executing idling stop control of the engine. .

  The present invention automatically stops the engine when a predetermined automatic stop condition is satisfied, and automatically restarts the engine by driving the starter with power supplied from a battery when the predetermined automatic restart condition is satisfied. An engine control device capable of executing idling stop control, wherein a battery voltage acquisition unit that acquires a battery voltage of the battery, a battery temperature acquisition unit that acquires a battery temperature of the battery, and a battery charge rate of the battery Battery charging rate acquisition means for performing, and idling stop permission battery charging rate acquisition means for acquiring an idling stop permission battery charging rate based on the minimum voltage of the battery voltage at the start of the engine, the battery temperature, and the battery charging rate. . And when the present battery charging rate acquired by the battery charging rate acquisition means is larger than the idling stop permission battery charging rate, it is configured to allow idling stop control.

  The operation of the present invention will be described below.

  First, assuming that the engine, starter, and battery temperatures are the same, the minimum battery voltage at the start of the engine is largely influenced mainly by the battery charge rate and the deterioration state of the battery. That is, when the battery charge rate is high with respect to the minimum voltage of the battery voltage at the time of starting the engine, it can be estimated that the battery deterioration state is large deterioration, and when the battery charge rate is low, the battery deterioration state is low deterioration. In the state where there is no deterioration of the battery, the influence of the battery charging rate is dominant in the minimum voltage of the battery voltage when starting the engine.

  In order to obtain the required startability of the engine from such a battery deterioration state, it is necessary to greatly recover the battery charge rate when the battery deterioration state is large. That is, it is necessary to set a large idling stop permission battery charging rate (threshold). On the other hand, when the deterioration state of the battery is small, the amount of battery charge rate recovery is relatively small. That is, it becomes possible to set the idling stop permission battery charging rate (threshold) relatively small.

  For this reason, in addition to the minimum battery voltage when starting the engine, the battery charging rate (threshold) is set in consideration of the battery charging rate when starting the engine. Thus, the idling stop permission determination can be performed using the more optimal idling stop permission battery charging rate. As a result, the opportunity for idling stop control can be increased as compared with the prior art, and fuel consumption can be improved.

  ADVANTAGE OF THE INVENTION According to this invention, the opportunity of idling stop control can be increased in the engine control apparatus which can perform idling stop control of an engine.

1 is a schematic configuration diagram of an engine, a starter, a battery, and the like to which an engine control device of the present invention is applied. It is a block diagram which shows the structure of control systems, such as ECU. It is a flowchart which shows an example of the idling stop permission control which ECU performs.

  Hereinafter, an embodiment of the present invention will be described with reference to FIG.

  The engine 1 is mounted on a vehicle such as an automobile. The engine 1 is a known power device that outputs power by burning fuel such as a gasoline engine or a diesel engine. For example, a throttle opening (intake air amount) of a throttle valve provided in an intake passage, fuel injection The operation state such as the amount and the ignition timing can be controlled. The crankshaft of the engine 1 is provided with a flywheel, and a ring gear is provided on the outer periphery of the flywheel.

  The operating state of the engine 1 is controlled by an ECU (Electronic Control Unit) 100. The ECU 100 executes various controls of the engine 1 including the above intake air amount control, fuel injection amount control, ignition timing control, and the like.

  The starter 2 is driven by power supplied from the on-vehicle battery 3 and meshes the pinion gear with the ring gear of the engine 1 to forcibly rotate (crank) the crankshaft. The drive of the starter 2 is controlled by the ECU 100. The starter 2 may be a motor or a motor generator.

  The battery 3 is charged with electric power generated by a generator such as an alternator (not shown). As a detection device related to the battery 3, a battery voltage detection device 101 that detects battery voltage, a battery current detection device 102 that detects battery current, a battery temperature detection device 103 that detects battery temperature, and a battery charge rate (remaining capacity [Ah]) / Full charge capacity [Ah]) × 100 [%]) is detected.

  Here, the battery voltage detection device 101 is an example of the “battery voltage acquisition unit” of the present invention, and the battery temperature detection device 103 is an example of the “battery temperature acquisition unit” of the present invention. The battery charge rate detection device 104 is an example of the “battery charge rate acquisition unit” in the present invention. Note that the battery charging rate may be estimated in the ECU 100 from outputs of the battery voltage detection device 101, the battery temperature detection device 103, and the like.

  The ECU 100 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a backup RAM, and the like.

  The ROM stores various control programs, maps that are referred to when the various control programs are executed, and the like. The CPU executes arithmetic processing based on various control programs and maps stored in the ROM. The RAM is a memory for temporarily storing calculation results from the CPU, data inputted from each sensor, and the backup RAM is a non-volatile memory for storing data to be saved when the engine 1 is stopped. It is.

  As shown in FIG. 2, the ECU 100 includes an engine speed sensor that detects the speed of the engine 1, a throttle opening sensor that detects the opening of the throttle valve, an accelerator opening sensor that detects the opening of the accelerator pedal, A vehicle speed sensor that outputs a signal corresponding to the vehicle speed of the vehicle and a brake pedal sensor that detects the amount of depression of the brake pedal are connected. Further, the ECU 100 is connected to various sensors such as the battery voltage detection device 101, the battery current detection device 102, the battery temperature detection device 103, and the battery charge rate detection device 104 described above. Signal is also input to the ECU 100.

  The ECU 100 is connected to a throttle motor 11 that opens and closes a throttle valve of the engine 1, an injector 12, a spark plug 13 (igniter), a starter 2, and the like.

  The ECU 100 controls the throttle valve opening of the engine 1 (intake air amount control (drive control of the throttle motor 11)) and fuel injection amount control (open / close control of the injector 12) based on the output signals of the various sensors described above. ), Various kinds of control of the engine 1 including ignition timing control (drive control of the spark plug 13) and the like are executed.

  Furthermore, the ECU 100 executes the following “idling stop control” and “idling stop permission control”.

[Idling stop control]
In the idling stop control (start and stop (S & S) control), the engine 1 is automatically stopped from the idling operation state, and the engine 1 is automatically restarted from the automatic stop state.

  Specifically, the engine 1 is automatically stopped when a predetermined automatic stop condition is satisfied during operation of the engine 1. Examples of the automatic stop condition include conditions such as the accelerator operation amount being “0”, the vehicle speed being “0”, and the brake pedal being depressed (ie, being turned on). When all of these conditions are satisfied, it is determined that the automatic stop condition is satisfied. When the automatic stop condition is satisfied, the fuel injection from the injector 12 is stopped (fuel cut). As a result, the engine 1 is no longer operated independently, and the engine 1 stops rotating after being idle to some extent due to inertia. The automatic stop condition is an example, and may be changed as appropriate.

  Further, when the automatic restart condition of the engine 1 is satisfied after the automatic stop of the engine 1, the automatic restart of the engine 1 is performed. Examples of the automatic restart condition include a condition that the accelerator operation amount is larger than “0” and that the depression of the brake pedal is released (off operation). When at least one of these conditions is satisfied, it is determined that the automatic restart condition is satisfied. When the automatic restart condition is satisfied, the engine 1 is cranked by driving the starter 2. While the fuel injection from the injector 12 is started during the cranking, the engine 1 is automatically started by igniting the spark plug 13. The automatic restart condition is an example and may be changed as appropriate.

[Idling stop permission control]
Next, the idling stop permission control executed by the ECU 100 will be described with reference to the flowchart of FIG. The control routine of FIG. 3 is repeatedly executed at predetermined intervals in the ECU 100 while the ignition of the vehicle is on.

  When the control routine of FIG. 3 is started, it is first determined in step ST101 whether or not the engine 1 has been started. Specifically, for example, based on the output of the battery current detection device 102, it is determined that the engine is started when a large current of a predetermined value or more flows through the battery 3. If the determination result of step ST101 is affirmative (YES), the process proceeds to step ST102. If the determination result in step ST101 is negative (NO), the process is temporarily terminated.

  In step ST102, based on the outputs of the battery voltage detection device 101, the battery temperature detection device 103, and the battery charge rate detection device 104, the lowest voltage of the battery 3 at the time of starting the engine (the lowest voltage at the time of cranking; (Also called voltage), battery temperature, and battery charge rate are acquired and temporarily stored in a RAM or the like.

  In step ST103, it is determined whether or not the minimum battery voltage at the time of engine start stored in step ST102 is greater than a predetermined value. About the predetermined value used for determination of this step ST103, the lower limit of the battery voltage for starting the engine 1 reliably is acquired beforehand by experiment or simulation, and is set based on the lower limit of the battery voltage.

  When the determination result of step ST103 is affirmative (YES) (when [battery minimum voltage> predetermined value]), idling stop control is permitted (step ST108).

  On the other hand, when the determination result of step ST103 is negative (NO) (when [battery minimum voltage ≦ predetermined value]), idling stop control is prohibited in step ST104. Thereafter, the process proceeds to step ST105.

  In step ST105, the idling stop permission battery charge rate (threshold) is obtained by referring to the idling stop permission map using the battery minimum voltage at the time of engine start, the battery temperature, and the battery charge rate stored in step ST102.

  Here, the idling stop permission map can reliably start the engine 1 by experiments or simulations in advance using the battery minimum voltage, the battery temperature, and the battery charging rate related to the deterioration state of the battery 3 as parameters. The battery charge rate (idling stop permission battery charge rate) is adapted to be mapped and stored in the ROM of the ECU 100.

  In this idling stop permission map, when the battery minimum voltage and the battery temperature are the same, when the battery charge rate is high (when the deterioration state of the battery 3 is large deterioration), when it is low (the deterioration state of the battery 3) Is set so that the idling stop permission battery charging rate becomes a large value compared to the case where the deterioration is small. In addition, in the idling stop permission map, when the battery charging rate is the same, the idling stop permission battery charging rate is set to a smaller value than when the battery minimum voltage and the battery temperature are high and low. ing.

  Next, in step ST106, the current battery charge rate is acquired based on the output of the battery charge rate detection device 104. Thereafter, the process proceeds to step ST107.

  In step ST107, it is determined whether or not the current battery charge rate acquired in step ST106 is greater than the idling stop permission battery charge rate obtained in step ST105. When the determination result is affirmative (YES) (when [battery charging rate> idling stop permission battery charging rate]), idling stop control is permitted (step ST108).

  On the other hand, when the determination result of step ST107 is negative (NO) (when [battery charge rate ≦ idling stop permission battery charge rate]), the process returns to step ST106, and the process of step ST106 (current battery charge rate) Acquisition process) and the process of step ST107 (determination process of [battery charge rate> idling stop permission battery charge rate]). And when the charge state of the battery 3 is improved by charging the battery 3 and the current battery charge rate becomes larger than the idling stop permission battery charge rate (the determination result of step ST107 is affirmative determination (YES)) If it is, the idling stop control is permitted (step ST108).

  In addition, the engine control apparatus of this invention is implement | achieved by performing step ST101-step ST108 of FIG. 3 by ECU100.

<Effect>
As described above, according to the present embodiment, idling stop control is permitted when the battery minimum voltage at the time of starting the engine is greater than a predetermined value. Further, when the minimum battery voltage at the time of starting the engine is equal to or lower than a predetermined value, the idling stop permission battery is determined based on the minimum battery voltage at the time of starting the engine and the battery charge rate at the time of starting the engine (the deterioration state of the battery 3). A charging rate is set, and idling stop control is permitted when the current battery charging rate is larger than the idling stop permission battery charging rate.

  Thus, in addition to the minimum battery voltage at the time of starting the engine, the battery charge rate related to the deterioration state of the battery 3 is taken into account to set the idling stop permission battery charge rate, thereby taking into account the battery deterioration state. The idling stop permission determination can be performed using a more optimal idling stop permission battery charging rate. As a result, it is possible to increase the idling stop control opportunity and improve the fuel efficiency as compared with the above-described conventional technology (a technology for setting the idling stop permission battery charging rate based only on the minimum voltage of the battery voltage at the time of starting the engine). be able to.

-Other embodiments-
In addition, embodiment disclosed this time is an illustration in all the points, Comprising: It does not become a basis of limited interpretation. Therefore, the technical scope of the present invention is not interpreted only by the above-described embodiments, but is defined based on the description of the scope of claims. Further, the technical scope of the present invention includes all modifications within the meaning and scope equivalent to the scope of the claims.

  INDUSTRIAL APPLICABILITY The present invention can be effectively used for an engine control apparatus that can execute idling stop control of an engine.

1 Engine 2 Starter 3 Battery 100 ECU
DESCRIPTION OF SYMBOLS 101 Battery voltage detection apparatus 102 Battery current detection apparatus 103 Battery temperature detection apparatus 104 Battery charge rate detection apparatus

Claims (1)

An idling stop control that automatically stops the engine when a predetermined automatic stop condition is satisfied, and automatically restarts the engine by supplying power from a battery when the predetermined automatic restart condition is satisfied. An executable engine control device,
Battery voltage acquisition means for acquiring the battery voltage of the battery;
Battery temperature acquisition means for acquiring the battery temperature of the battery;
Battery charge rate acquisition means for acquiring a battery charge rate of the battery;
An idling stop permission battery charge rate acquisition means for acquiring an idling stop permission battery charge rate based on the minimum voltage of the battery voltage at the time of engine start, the battery temperature, and the battery charge rate;
An engine control device configured to permit idling stop control when a current battery charging rate acquired by the battery charging rate acquiring unit is larger than the idling stop permission battery charging rate.

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