JP2017150421A - Control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for an internal combustion engine capable of preventing fluctuation of engine speed even when auxiliary machinery of which torque required to obtain constant output is changed due to a change of humidity is actuated in an idling state of the internal combustion engine (engine) and in a delay state of ignition timing aiming at an early temperature rise of a catalyst.SOLUTION: A control device for an internal combustion engine includes: a humidity detection section for detecting humidity of air; an auxiliary machinery operation state detection section for detecting an operation state of auxiliary machinery that is driven by using torque of the internal combustion engine and of which load torque required to obtain constant output is changed in accordance with the humidity of the air; and means for raising a temperature of a catalyst installed in an exhaust passage by delaying ignition timing of the internal combustion engine. In the catalyst temperature rise state, suction air amount of the internal combustion engine is corrected based on the humidity of the air and the operation state of the auxiliary machinery, and ignition timing of the internal combustion engine is controlled in accordance with the corrected suction air amount or the torque of the internal combustion engine.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a control device for an internal combustion engine, and more particularly to a control device for an internal combustion engine that controls the rotational speed of the internal combustion engine in an idle state.

  In the idling state of the internal combustion engine (engine), the target engine speed is lowered to improve fuel efficiency and the engine speed is stabilized in order to stabilize the engine speed based on the actual engine speed and the target engine speed. Feedback control is performed. As a method for realizing this feedback control, a method for controlling the intake air amount or the ignition timing is widely known, and it is also widely known that humidity is taken into account when determining the ignition timing and the intake air amount. .

  Further, as in the cold start of the internal combustion engine described in Japanese Patent Application Laid-Open No. 6-249117, ignition is performed at the time of catalyst temperature rise in which early temperature rise of the catalyst installed in the exhaust passage is required to purify the exhaust gas. A method of increasing the exhaust temperature by retarding the timing is widely known.

  When the feedback control is performed and the catalyst temperature is raised, the engine speed may deviate from the target speed. For example, an auxiliary machine driven using engine torque is in an operating state from a stopped state. The case where it changes to is mentioned. When the state of the auxiliary machine changes from the stopped state to the activated state, torque for driving the auxiliary machine is required, and the torque is increased by increasing the throttle opening and increasing the intake air amount to the engine. The engine speed is prevented from deviating from the target speed by retarding the response ignition timing and reducing the engine torque.

JP-A-6-249117

  However, as described above, the ignition timing is greatly retarded when the catalyst temperature rises, and if it is further retarded, misfire may occur. The decrease in torque due to corners could not be adjusted sufficiently. For this reason, there is a problem in the riding performance due to the engine speed deviating from the target speed.

  The present invention has been made in view of the above problems, and the object of the present invention is to control the humidity when the internal combustion engine (engine) is in an idle state and a retarded ignition timing for the purpose of raising the catalyst temperature. To provide a control device for an internal combustion engine that can suppress the deviation of the engine speed from the target engine speed even when auxiliary machinery whose torque required to obtain a constant output due to the change operates. is there.

  In order to solve the above-described problem, an internal combustion engine control apparatus according to the present invention is an internal combustion engine control apparatus for controlling the number of revolutions of an internal combustion engine in an idle state, the air being sucked into the internal combustion engine A humidity detector that detects the humidity of the engine and an operating state of an auxiliary machine that is driven using the torque of the internal combustion engine and that changes in torque required to obtain a constant output according to the humidity of the air An auxiliary machine operating state detecting unit and a means for retarding the ignition timing for the purpose of raising the catalyst temperature, and the intake air of the internal combustion engine based on the humidity of the air and the operating state of the auxiliary machine The quantity is corrected, and the ignition timing of the internal combustion engine is controlled by the corrected intake air quantity or the torque of the internal combustion engine.

  According to the present invention, the intake air amount is corrected based on the humidity of the air sucked into the internal combustion engine and the operating state of the auxiliary machine driven using the drive torque of the internal combustion engine, and the ignition timing is controlled. By this, when the auxiliary machine in which the driving torque necessary to obtain a constant output is changed by the change of humidity is operated in the idle state of the internal combustion engine and the retarded state of the ignition timing for the purpose of raising the catalyst temperature, Can be prevented from deviating from the target rotational speed.

  Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

1 is a system configuration diagram schematically showing an overall configuration of an internal combustion engine including an embodiment of a control device (ECU) for an internal combustion engine according to the present invention. The block diagram which shows the relationship of the input / output signal of ECU shown in FIG. The block diagram which shows the internal structure of ECU shown in FIG. The engine speed, engine state, air conditioner operating state, compressor state, external load, final intake air amount, ignition timing, engine torque in the conventional control when the air conditioner is operated from the stopped state when the engine is in the idle state The timing chart explaining an example of the change of. The engine speed, engine state, air conditioner operating state, compressor state in the conventional control when the air conditioner is operated from the stopped state when the engine is idling and the ignition timing is retarded for the purpose of raising the catalyst temperature. FIG. 6 is a timing chart illustrating an example of changes in external load, final intake air amount, ignition timing, and engine torque. The figure which shows the relationship between humidity and an intake air amount correction value. The flowchart explaining the calculation processing procedure of the intake air amount correction value in the control processing by the ECU shown in FIG. The flowchart explaining the calculation process sequence of the intake air amount correction value in the control process by ECU shown in FIG.

  Hereinafter, an embodiment of a control device for an internal combustion engine according to the present invention will be described with reference to the drawings.

  FIG. 1 schematically shows an overall configuration of an internal combustion engine including an embodiment of an engine control unit (ECU) which is a control device for an internal combustion engine according to the present invention.

  As shown in the figure, an engine (internal combustion engine) 1 includes a piston 2, an intake valve 3, and an exhaust valve 4. The intake air passes through the airflow sensor (air flow meter) 12 and the humidity sensor 28 and enters the throttle valve 19, and enters the combustion chamber 21 of the engine 1 through the intake pipe 10 and the intake valve 3 from the collector 15, which is a branch portion. Supplied. The airflow sensor 12 outputs a signal indicating the intake air flow rate of the intake air to the ECU 9, and the humidity sensor 28 outputs a signal indicating the humidity of the intake air to the ECU 9. Fuel is supplied from the fuel tank 23 to the engine 1 by the low-pressure fuel pump 24, and further increased to a pressure required for fuel injection by the high-pressure fuel pump 25. The high pressure fuel is injected and supplied from the fuel injection valve 5 to the combustion chamber 21 of the engine 1, and is ignited by the spark plug 6 that receives energy from the ignition coil 7. The ignition control is performed by the energization control to the ignition coil 7 at a desired ignition timing by the ECU 9. The exhaust gas after combustion is discharged to the exhaust pipe 11 through the exhaust valve 4 and is purified when passing through the exhaust purification catalyst 30. Air-fuel ratio sensors 31 and 32 are provided upstream and downstream of the catalyst, and output signals indicating the air-fuel ratio of the exhaust gas before purification and the exhaust gas after purification to the ECU 9.

  At the time of cold start that requires the catalyst 30 to be quickly heated, the ignition timing by the ignition coil 7 and the ignition coil 6 is retarded, and the temperature of the catalyst 30 is raised quickly by increasing the exhaust temperature.

  The ECU 9 includes a signal from the accelerator opening sensor 22 that measures the accelerator opening, a signal from the crank angle sensor 16 that measures the rotation angle of the crankshaft of the engine 1, and a throttle sensor that measures the opening of the throttle valve 19 ( The ECU 9 controls the electric throttle 18, the low pressure fuel pump 24, the high pressure fuel pump 25, the fuel injection valve 5 and the like provided in the throttle valve 19 as well. Yes.

  Further, as an example of an auxiliary machine, an air conditioner (vehicle air conditioner) (not shown) is provided, and the air conditioner switch 29 is turned on and off so that the ECU 9 operates the air conditioner via the air conditioner CU (air conditioner control unit) 27. Control the state. In the present embodiment, the ECU 9 controls the air conditioner system via the air conditioner CU27. However, the ECU 9 may directly control the air conditioner system without using the air conditioner CU27.

  An air conditioner system (not shown) includes a compressor, a condenser, an evaporator, and the like. The compressor is connected to the engine 1 via a pulley and a belt, and is driven by the engine 1. Therefore, when the engine is in an idle state and the air conditioner is stopped, the external load of the engine increases when the air conditioner transitions to the operating state. Since the external load increases, the electric throttle 18 is controlled by controlling the electric throttle 18 so that the engine rotational speed becomes the target rotational speed, and the ignition timing is adjusted by controlling the ignition coil 7.

  FIG. 2 schematically shows an example of the internal configuration of ECU 9 shown in FIG. 1, and is a block diagram showing the relationship between input and output signals of ECU 9 shown in FIG.

  The ECU 9 includes an I / O LSI 9a including an A / D converter, a CPU 9b, and the like. As described above, the signal of the accelerator opening sensor 22, the signal of the crank angle sensor 16, the signal of the throttle sensor, the airflow sensor 12 A signal related to the intake air amount, a signal related to the humidity of the intake air from the humidity sensor 28, an on / off signal of the air conditioner switch 29 for switching the operation state of the air conditioner, and the like. Further, the ECU 9 converts various control signals calculated by a predetermined calculation process into an actuator, such as an electric throttle 18, a high pressure fuel pump 25, a low pressure fuel pump 24, an ignition coil 7, an air conditioner CU 27 as a control unit, and the like. To control the operating state of each actuator.

  FIG. 3 shows an internal configuration of the ECU shown in FIG. Such a control block is realized by hardware, software, or a combination thereof.

  3 calculates the engine speed based on the signal from the crank angle sensor 16, and the calculation results are used as a basic intake air amount calculation unit 307, an idle determination unit 305, and an ignition timing calculation unit. To 306.

  The load calculation unit 302 calculates the load state of the engine 1 based on the opening of the throttle valve 19 obtained from the throttle sensor and the intake air amount obtained from the airflow sensor 12, and the calculation result is used as a basic intake air amount calculation unit. 307, the idle determination unit 305, and the ignition timing calculation unit 306.

  The humidity calculator 303 detects the humidity of the intake air based on the humidity information of the intake air obtained from the humidity sensor 28, and transmits the detection result to the intake air amount correction value calculator 308.

  The air conditioner operation state detection unit (auxiliary device operation state detection unit) 304 determines (detects) whether the air conditioner is operating or stopped based on the air conditioner system information obtained via the air conditioner CU 27, and inhales the determination result. It transmits to the air amount correction value calculation unit 308.

  In the idle determination unit 305, the engine speed is calculated based on the engine speed calculated by the above-described rotation speed calculation unit 301, the load of the engine 1 calculated by the load calculation unit 302, and the accelerator opening obtained from the accelerator opening sensor 22. 1 is determined to be in an idle state, and the determination result is transmitted to the basic intake air amount calculation unit 307, the intake air amount correction value calculation unit 308, and the ignition timing calculation unit 306.

  In the ignition timing calculation unit 306, based on the information on the engine rotation speed calculated by the rotation speed calculation unit 301, the load of the engine 1 calculated by the load calculation unit 302, and the idle state determined by the idle determination unit 305, basic ignition is performed. The timing is calculated, the ignition coil 7 is controlled based on the calculation result, and the ignition plug 6 ignites.

  In the basic intake air amount calculation unit 307, based on the information on the engine speed calculated by the above-described rotation speed calculation unit 301, the load of the engine 1 calculated by the load calculation unit 302, and the idle state information determined by the idle determination unit 305, The basic intake air amount is calculated, and the calculation result is transmitted to the final intake air amount calculation unit 309.

  The intake air amount correction value calculation unit 308 displays the idle state information determined by the idle determination unit 305, the intake air humidity calculated by the humidity detection unit 303, and the air conditioner operation state determined by the air conditioner operation state detection unit 304. Based on this, the intake air amount correction value is calculated, and the calculation result is transmitted to the final intake air amount calculation unit 309. The calculation process of the intake air amount correction value in the intake air amount correction value calculation unit 308 will be described in detail later.

  In the final intake air amount calculation unit 309, the final intake air amount is calculated based on the basic intake air amount calculated by the basic intake air amount calculation unit 307 and the intake air amount correction value calculated by the intake air amount correction value calculation unit 308. And the electric throttle 18 is controlled based on the calculation result to adjust the intake air amount of the engine 1.

  FIG. 4 is a timing chart showing an example of processing of the related art when the air conditioner transitions to the operating state when the engine is in an idle state and the air conditioner is stopped.

  When the engine speed is equal to or lower than the upper limit threshold and equal to or higher than the lower limit threshold, it is determined that the engine is in the idle state. When the air conditioner switch is turned on at T1 in FIG. 4, the compressor is driven by the engine 1 via a pulley and a belt at T2 after a certain time, so the external load of the engine increases. In T1 to T2 in FIG. 4, in order to compensate for an increase in the external load of the engine due to the compressor driving, the low-response electric throttle 18 is controlled to increase the intake air amount and increase the engine torque, and the ignition coil 7 is controlled to retard the ignition timing, which is a high response, thereby reducing the engine torque and adjusting the engine torque. In this way, a deviation of the engine speed from the target engine speed due to a change in engine torque is prevented.

  Next, from T2 to T3 in FIG. 4, the external load increases when the compressor is driven. Therefore, the ignition timing, which is a high response, is advanced to increase the engine torque and the intake air amount is decreased. To reduce the engine torque and adjust the engine torque. In this way, a deviation of the engine speed from the target engine speed due to a change in engine torque is prevented.

  FIG. 5 is a timing chart showing an example of processing of the prior art when the air conditioner transitions to the operating state while the engine is in an idle state and the air conditioner is stopped at the time of cold start that requires an early temperature increase of the catalyst 30. .

  As described in the explanation of FIG. 4, when the engine speed of FIG. 5 is equal to or lower than the upper threshold and the lower threshold, it is determined that the engine is in an idle state, and when the air conditioner switch is turned on in T1 of FIG. At T2 after a certain time, the compressor is driven by the engine 1 via a pulley and a belt, so that the external load of the engine increases. In order to compensate for the increase in the external load of the engine, the low-response electric throttle 18 is controlled to increase the intake air amount and increase the engine torque. However, the ignition timing is already greatly delayed due to the early temperature rise of the catalyst. If the ignition timing is retarded, the misfire limit will be reached.Therefore, the engine torque cannot be adjusted sufficiently due to the retarded ignition timing, the engine torque increases, and the engine speed increases. There has been a problem that the ride performance becomes worse due to deviation from the target engine speed.

  FIG. 6 is an example of a table showing the relationship between the humidity and the intake air amount correction value that is referred to when the intake air amount correction value calculation unit 308 shown in FIG. 3 calculates the intake air amount correction value. In the air conditioner as an auxiliary machine, the torque required to obtain a certain output decreases as the humidity decreases. Therefore, the lower the humidity, the smaller the intake air amount correction value. By using this intake air amount correction value, the intake air amount is corrected so as to decrease as the humidity decreases. When the humidity is high, the intake air amount correction value is increased in the negative direction, and when the humidity is low, the intake air amount compensation value is set to be close to zero. In other words, when the humidity is high, the final intake air amount is greatly reduced by the intake air amount correction value, and when the humidity is low, the final intake air amount is decreased by the intake air amount correction value.

  FIG. 7 shows the processing of the present technology (calculation of the intake air amount correction value of the ECU 9) when the air conditioner transitions to the operating state while the engine is idling and the air conditioner is stopped at the time of cold start where the catalyst 30 is required to be quickly heated. 6 is a timing chart illustrating an example of control processing using an intake air amount correction value calculated by a unit 308.

  As described in the explanation of FIG. 5, when the engine speed in FIG. When the air conditioner switch is turned on at T1 in FIG. 7, the compressor is driven by the engine 1 via a pulley and a belt at T2 after a certain time, so that the external load of the engine increases. From T1 to T2 in FIG. 7, the intake air amount that compensates for the increase in the external load due to the driving of the compressor is increased. As described above, the air conditioner as an auxiliary device obtains a constant output as the humidity decreases. Therefore, the torque required for this is reduced. Therefore, the intake air amount correction value calculation unit 308 of the ECU 9 calculates the intake air amount correction value with reference to the correction value table shown in FIG. 6, and corrects the intake air amount. By correcting the intake air amount, the final intake air amount is reduced from the dotted line portion of FIG. 7 to the value of the solid line portion. By correcting the final intake air amount to an appropriate value according to the humidity, the increase in engine torque due to the increase in intake air amount can be adjusted by retarding the ignition timing. Stabilize. Thus, the deviation of the engine speed from the target engine speed due to the increase in the engine torque can be suppressed, and the riding performance can be maintained. Further, in FIGS. T2 to T3, since the compressor is already driven, the intake air amount is not corrected.

  FIG. 8 is a flowchart for explaining the calculation processing procedure of the intake air amount correction value in the control processing by the ECU 9 shown in FIG. The arithmetic processing shown in FIG. 8 is repeatedly executed at a predetermined arithmetic cycle. That is, the processing from step S800 to step S806 is repeatedly executed at a predetermined calculation cycle by the ECU 9 shown in FIG. 1 (for example, every 1 ms that is a predetermined time or every 6 deg that is a predetermined crank angle). . Moreover, it is good also as what calculates by the interruption process from the various apparatuses to ECU9 shown in FIG.

  First, in step S800, the idle determination unit 305 determines the accelerator opening obtained from the accelerator opening sensor 22, the engine speed calculated by the above-described rotation speed calculation unit 301, and the engine load calculated by the load calculation unit 302. Based on this, it is determined whether or not the engine 1 is in an idle state.

  Next, in step S801, the intake air amount correction value calculation unit 308 determines whether the engine 1 is in an idle state from the determination result determined in step S800. If the engine 1 is in an idle state, the process proceeds to step S802. move on. On the other hand, if the engine is not in the idle state, the process proceeds to step S806, the intake air amount correction value is set to 0, and the present calculation process is terminated.

  In step S802, the air conditioner operation state detection unit 304 determines whether the air conditioner is operating based on the air conditioner system information obtained from the air conditioner CU27.

  Next, in step S803, the intake air amount correction amount calculation unit 308 determines whether the air conditioner is stopped from the determination result determined in step S802. If the air conditioner is stopped, the process proceeds to step S804, and the air conditioner ( Auxiliary machine) corrects intake air amount while stopped. On the other hand, if the air conditioner is operating, the process proceeds to step S806, the intake air amount correction value is set to 0, and the present calculation process is terminated.

  In step S804, the humidity detector 303 detects the humidity of the intake air based on the humidity information of the intake air obtained from the humidity sensor 28.

  Note that steps S800 and S801, steps S802 and S803, and step S804 described above are in no particular order.

  Next, in step S805, the intake air amount correction value calculation unit 308 calculates an intake air amount correction value based on the humidity detected in step S804. As described above, the intake air amount correction value is set to be larger in the negative direction when the humidity is high, and the intake air amount compensation is set to be close to 0 when the humidity is low. In other words, when the humidity is high, the final intake air amount is greatly reduced by the intake air amount correction value, and when the humidity is low, the final intake air amount is decreased by the intake air amount correction value.

  Then, based on the intake air amount correction value calculated by the arithmetic processing shown in FIG. 8, the final intake air amount calculation unit 308 corrects the basic intake air amount to calculate the final intake air amount and the final intake air amount. The ignition timing is adjusted so that the torque increased by the increase in the air amount is reduced.

  Thereby, the torque of the engine 1 is stabilized, and fluctuations in the rotational speed of the engine 1 can be suppressed. Further, when the engine 1 is in an idling state, even if an auxiliary device such as an air conditioner in which a torque necessary for obtaining a constant output is changed due to a change in humidity operates, fluctuations in the rotation speed of the engine 1 can be prevented. it can.

  In addition, this invention is not limited to above-described embodiment, Various deformation | transformation forms are included. For example, the above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to one having all the configurations described.

  Further, the control lines and information lines are those that are considered necessary for the explanation, and not all the control lines and information lines on the product are necessarily shown. Actually, it may be considered that almost all the components are connected to each other.

1. Engine (internal combustion engine)
2 ... Piston 3 ... Intake valve 4 ... Exhaust valve 5 ... Fuel injection valve 6 ... Spark plug 7 ... Ignition coil 9 ... ECU
DESCRIPTION OF SYMBOLS 10 ... Intake pipe 11 ... Exhaust pipe 12 ... Air flow sensor 15 ... Collector 16 ... Crank angle sensor 18 ... Electric throttle 19 ... Throttle valve 21 ... Combustion chamber 22 ... Accelerator opening sensor 23 ... Fuel tank 25 ... High pressure fuel pump 27 ... Air conditioner CU
28 ... Humidity sensor 29 ... Air conditioner switch 30 ... Catalyst 31 ... Air-fuel ratio sensor 32 ... Air-fuel ratio sensor 301 ... Rotational speed calculation unit 302 ... Load calculation unit 303 ... Humidity detection unit 304 ... Air conditioner operation state detection unit (auxiliary device operation state detection) Part)
305 ... Idle determination unit 306 ... Ignition timing calculation unit 307 ... Basic intake air amount calculation unit 308 ... Intake air amount correction value calculation unit 309 ... Final intake air amount calculation unit

Claims (3)

A control device for an internal combustion engine for controlling the rotational speed of the internal combustion engine,
A humidity detector that detects the humidity of the air;
An auxiliary machine operating state detector that detects the operating state of the auxiliary machine that is driven using the torque of the internal combustion engine and that changes the load torque required to obtain a constant output according to the humidity of the air; ,
Means for raising the temperature of the catalyst installed in the exhaust passage by retarding the ignition timing of the internal combustion engine,
In the temperature rising state of the catalyst, the intake air amount of the internal combustion engine is corrected based on the humidity of the air and the operating state of the auxiliary machine, and the internal combustion engine is adjusted according to the corrected intake air amount or the torque of the internal combustion engine. A control apparatus for an internal combustion engine, characterized by controlling ignition timing. The control apparatus for an internal combustion engine according to claim 1,
The control apparatus for an internal combustion engine, wherein the control apparatus corrects the intake air amount in a decreasing direction as the humidity of the air decreases. The control apparatus for an internal combustion engine according to claim 1,
The control device of the internal combustion engine, wherein the control device corrects the intake air amount while the auxiliary machine is stopped.

Images