JP6539222B2 - Control device for internal combustion engine - Google Patents

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 number of revolutions of the internal combustion engine in an idle state.

  In an idle state of an internal combustion engine (engine), the target engine speed of the engine speed is lowered to improve fuel efficiency, and the engine speed and the target engine speed are calculated to stabilize the engine speed. Feedback control. As a method of realizing this feedback control, a method of controlling the intake air amount or the ignition timing is widely known, and it is also widely known to consider the humidity when determining the ignition timing and the intake air amount. .

  In addition, at the time of catalyst temperature rise where an early temperature rise of the catalyst installed in the exhaust passage is required to purify the exhaust gas as in the cold start of the internal combustion engine described in JP-A-6-249117, ignition takes place. It is widely known that the timing is delayed to raise the exhaust temperature.

  During the feedback control and the catalyst temperature rise, the engine speed may deviate from the target speed, and one example is an auxiliary machine driven using engine torque from a stop state to an operating state There is a case of transition to When the state of the above-mentioned accessory changes from the stopped state to the operating state, a torque for driving the accessory is required, and the torque is increased by increasing the throttle opening and increasing the amount of intake air to the engine. By retarding the ignition timing, which is the response, and reducing the torque of the engine, the engine rotational speed is prevented from deviating from the target rotational speed.

Japanese Patent Laid-Open No. 6-249117

  However, as described above, the ignition timing is greatly retarded at the time of catalyst temperature rise, and there is a possibility of misfiring if it is further retarded. The torque reduction due to the angle could not be adjusted sufficiently. Therefore, there is a problem in the rideability due to the rotational speed of the engine deviating from the target rotational speed.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an internal combustion engine (engine) in an idle state and a retarded state of ignition timing for the purpose of catalyst temperature increase. To provide a control device of an internal combustion engine capable of suppressing deviation of an engine speed from a target engine speed even if an accessory is operated in which a torque required to obtain a constant output is changed due to a change. is there.

  In order to solve the problems described above, a control device of an internal combustion engine according to the present invention is a control device of an internal combustion engine for controlling the number of revolutions of the internal combustion engine in an idle state, and the air taken into the internal combustion engine And an operating condition of an accessory which is driven using the torque of the internal combustion engine and in which the torque required to obtain a constant output according to the humidity of the air changes And a means for retarding the ignition timing for the purpose of raising the temperature of the catalyst, and the intake air of the internal combustion engine based on the humidity of the air and the operating state of the The present invention is characterized in that the ignition timing of the internal combustion engine is controlled by correcting the amount and the intake air amount after correction or the torque of the internal combustion engine.

  According to the present invention, the amount of intake air is corrected based on the humidity of the air taken into the internal combustion engine and the operating state of the accessory driven using the driving torque of the internal combustion engine, and the ignition timing is controlled. Therefore, in the idle state of the internal combustion engine and the retarded state of the ignition timing for the purpose of catalyst temperature rise, when the auxiliaries are operated in which the drive torque required to obtain a constant output changes due to the change of humidity. It is possible to suppress deviation of the rotational speed of the target from the target rotational speed.

  Problems, configurations, and effects other than those described above will be apparent from the description of the embodiments below.

FIG. 1 is a system configuration diagram schematically showing an entire configuration of an internal combustion engine including an embodiment of a control device (ECU) of an internal combustion engine according to the present invention. FIG. 2 is a block diagram showing the relationship between input and output signals of the ECU shown in FIG. 1; FIG. 2 is a block diagram showing an internal configuration of an ECU shown in FIG. 1; The engine speed, engine state, air conditioner operating state, compressor state, external load, final intake air amount, ignition timing, engine torque in the control of the prior art when the air conditioner is operated from the stopped state when the engine is idle The timing chart explaining an example of change of. Engine rotational speed, engine state, air conditioner operating state, compressor state in the prior art control when the air conditioner is operated from the stopped state when the engine is idle and when the ignition timing is retarded for the purpose of catalyst temperature increase. The timing chart explaining an example of the change of an external load, the amount of final intake air, ignition timing, and the torque of an engine. The figure which shows the relationship between humidity and intake air amount correction value. FIG. 7 is a flowchart (at the time of start of a cold machine) for explaining the calculation processing procedure of the intake air amount correction value in the control processing by the ECU shown in FIG. 1. FIG. 6 is a flowchart illustrating a calculation processing procedure of an intake air amount correction value in the control processing by the ECU shown in FIG. 1;

  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 the entire configuration of an internal combustion engine including an embodiment of an engine control unit (ECU) which is a control device of an internal combustion engine according to the present invention.

  As shown, an engine (internal combustion engine) 1 is provided with a piston 2, an intake valve 3, and an exhaust valve 4. The intake air passes through the air flow sensor (air flow meter) 12 and the humidity sensor 28 and enters the throttle valve 19, and from the collector 15 which is a branch portion to the combustion chamber 21 of the engine 1 through the intake pipe 10 and the intake valve 3. Supplied. The air flow sensor 12 outputs a signal representing an intake flow rate of intake air to the ECU 9, and the humidity sensor 28 outputs a signal representing 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 is further raised by the high pressure fuel pump 25 to the pressure required for fuel injection. 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 has received energy from the ignition coil 7. The ignition control is performed by energization control to the ignition coil 7 at a desired ignition timing by the ECU 9. Exhaust gas after combustion is discharged to the exhaust pipe 11 through the exhaust valve 4 and is purified when passing through the catalyst 30 for exhaust gas purification. Air-fuel ratio sensors 31, 32 are provided upstream and downstream of the catalyst, and output signals representing the air-fuel ratios of the exhaust gas before purification and the exhaust gas after purification to the ECU 9.

  At the start of a cold machine where an early temperature rise of the catalyst 30 is required, the ignition timing by the ignition coil 7 and the ignition coil 6 is retarded, and the exhaust temperature is raised to raise the temperature of the catalyst 30 early.

  The ECU 9 also includes a signal from an 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 ( While the signal etc. of (not shown) is also input, the electronically controlled throttle 18 provided on the throttle valve 19, the low pressure fuel pump 24, the high pressure fuel pump 25, the fuel injection valve 5, etc. are also controlled by the ECU 9 There is.

  Further, an air conditioner (air conditioner for a vehicle) (not shown) is disposed as an example of the auxiliary machine, 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 CU 27. However, the ECU 9 may directly control the air conditioner system without using the air conditioner CU 27.

  The air conditioning system (not shown) comprises a compressor, a condenser, an evaporator and the like, and 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 idle and the air conditioner is stopped, the external load of the engine increases when the air conditioner shifts to the operating state. Since the external load increases, the amount of air intake to the engine is controlled by controlling the electronically controlled throttle 18 so that the engine speed becomes the target speed, and the ignition timing is adjusted by controlling the ignition coil 7.

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

  The ECU 9 is composed of an I / O LSI 9a including an A / D converter, a CPU 9b and the like, and 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 relating to the amount of intake air, a signal relating to the humidity of the intake air of the humidity sensor 28, an on / off signal of the air conditioner switch 29 for switching the operating state of the air conditioner, etc. are input. Further, the ECU 9 controls various control signals calculated by predetermined arithmetic processing, as an actuator, the electronically controlled throttle 18, the high pressure fuel pump 25, the low pressure fuel pump 24, the ignition coil 7, the air conditioner CU27 as a control unit, etc. To control the operating state of each actuator.

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

  The engine speed calculation unit 301 of the ECU 9 shown in FIG. 3 calculates the engine rotation speed based on the signal of the crank angle sensor 16, and the calculation result is used as a basic intake air amount calculation unit 307, an idle determination unit 305 and an ignition timing calculation unit. Send to 306.

  The load calculation unit 302 calculates the load condition of the engine 1 based on the opening degree of the throttle valve 19 obtained from the throttle sensor and the intake air amount obtained from the air flow sensor 12 and calculates the basic intake air amount calculation unit 307 and the idle determination unit 305 and the ignition timing calculation unit 306.

  The humidity calculation unit 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 calculation unit 308.

  The air conditioner operating state detecting unit (auxiliary machine operating state detecting 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 sucks the determination result. It is transmitted to the air amount correction value calculation unit 308.

  In the idle determination unit 305, based on the engine rotational speed calculated by the above-described rotational speed calculation unit 301, the load of the engine 1 calculated by the above-described load calculation unit 302, and the accelerator opening obtained from the accelerator opening sensor 22, It is determined whether or not 1 is in the idle state, and the determination result is sent 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, basic ignition is performed based on information of the engine speed calculated by the above-mentioned 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. The timing is calculated, and the ignition coil 7 is controlled based on the calculation result to ignite by the ignition plug 6.

  In the basic intake air amount calculation unit 307, based on the engine rotation 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.

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

  The final intake air amount calculation unit 309 calculates the final intake air amount 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 described above. Is calculated, and the electronically controlled 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 prior art when the air conditioner shifts to the operating state when the engine is idle and the air conditioner is stopped.

  When the engine speed is equal to or lower than the upper threshold and equal to or higher than the lower threshold, it is determined that the engine is in the idle state. In T1 of FIG. 4, when the air conditioner switch is turned on, the compressor is driven by the engine 1 through the pulley and the belt at T2 after a predetermined time, so the external load on the engine increases. From T1 to T2 in FIG. 4, in order to compensate for the increase in the external load of the engine due to the compressor drive, the electronically controlled throttle 18 having a low response is controlled to increase the intake air amount to increase the torque of the engine, and The torque of the engine is reduced by controlling the engine speed 7 and retarding the ignition timing which is a high response to adjust the torque of the engine. In this manner, 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, since the external load is increased by driving the compressor, the ignition timing which is high response is advanced to increase the torque of the engine while decreasing the intake air amount. Reduces the torque of the engine and adjusts the torque of the engine. In this manner, 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 the process of the prior art when the air conditioner is switched to the operating state while the engine is idle and the air conditioner is stopped at the start of a cold state where an early temperature rise of the catalyst 30 is required. .

  As described in the description of FIG. 4, when the engine speed in FIG. 5 is equal to or lower than the upper limit threshold and equal to or higher than the lower limit threshold, it is determined to be idle. At T2 after a certain time, the compressor is driven by the engine 1 through the pulleys and the belt, so the external load on the engine increases. In order to compensate for the increase in the external load of the engine, the low response electronically controlled throttle 18 is controlled to increase the amount of intake air and torque of the engine, but the ignition timing is already too late for the early temperature rise of the catalyst. Since the engine is at a corner and the ignition timing is retarded, it becomes a misfire limit, so the engine torque can not be sufficiently adjusted due to the retardation of the ignition timing, the engine torque increases, and the engine speed increases. There is a problem that the vehicle deviates from the target engine speed and the rideability deteriorates.

  FIG. 6 is an example of a table showing the relationship between humidity and the intake air amount correction value, which is referred to when the intake air amount correction value is calculated by the intake air amount correction value calculation unit 308 shown in FIG. Since the air conditioner as an auxiliary machine has a lower humidity and a lower torque to obtain a constant output, the lower the humidity, the smaller the intake air amount correction value. By using this intake air amount correction value, the amount of intake air is corrected to decrease as the humidity decreases. When the humidity is high, the intake air amount complement is set to be close to zero so that the intake air amount correction value is increased in the negative direction. 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 small by the intake air amount correction value.

  FIG. 7 shows the processing of the present technology when the air conditioner transitions to the operating state while the engine is in an idle state and the air conditioner is stopped at a cold machine start where an early temperature rise of the catalyst 30 is required. 6 is a timing chart showing an example of control processing using the intake air amount correction value calculated by the unit 308. FIG.

  As described in the description of FIG. 5, when the engine speed of FIG. 7 is less than or equal to the upper threshold and greater than or equal to the lower threshold, it is determined that the vehicle is in the idle state. In T1 of FIG. 7, when the air conditioner switch is turned on, the compressor is driven by the engine 1 through the pulley and the belt at T2 after a predetermined time, so the external load on the engine increases. From T1 to T2 in FIG. 7, the intake air amount is increased to compensate for the increase in external load due to the compressor being driven, but as described above, the air conditioner as an auxiliary machine obtains a constant output by the decrease in humidity. The required torque is reduced. Therefore, the intake air amount correction value calculation unit 308 of the ECU 9 refers to the correction value table shown in FIG. 6, calculates the intake air amount correction value, and corrects the intake air amount. By correcting the amount of intake air, the final amount of intake air decreases from the dotted line to the solid line in FIG. By correcting the final intake air amount to an appropriate value according to the humidity, it is possible to adjust the increase of the engine torque due to the increase of the intake air amount by the retardation of the ignition timing, and the engine torque becomes Stabilize. As described above, the deviation of the engine speed from the target engine speed due to the increase of the engine torque can be suppressed, and the rideability can be maintained. Further, in FIGS. T2 to T3, since the compressor is in the drive state, the correction of the intake air amount is not performed.

  FIG. 8 is a flow chart 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 calculation process shown in FIG. 8 is repeatedly performed in a predetermined calculation cycle. That is, the processing from step S800 to step S806 is repeatedly executed by the ECU 9 shown in FIG. 1 at a predetermined calculation cycle (for example, every 1 ms which is a predetermined time or every 6 degrees which is a predetermined crank angle) . Further, calculation may be performed using an interrupt process from various devices to the ECU 9 shown in FIG. 1 as a trigger.

  First, in step S800, the idle determination unit 305 determines the accelerator opening obtained from the accelerator opening sensor 22, the engine rotational speed calculated by the above-described rotational speed calculation unit 301, and the engine load calculated by the load calculation unit 302. Based on it, it is determined whether 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 the idle state based on the determination result determined in step S800. If the engine 1 is in the idle state, the process proceeds to step S802. move on. On the other hand, when the idle state is not set, the process proceeds to step S806, and the intake air amount correction value is set to 0 to end the present arithmetic processing.

  Next, in step S802, based on the air conditioner system information obtained from the air conditioner CU 27, the air conditioner operating state detection unit 304 determines whether the air conditioner is in operation.

  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 ( Compensate the intake air amount while the accessory is stopped. On the other hand, when the air conditioner is in operation, the process proceeds to step S806, the intake air amount correction value is set to 0, and the present arithmetic processing is ended.

  Next, in step S804, the humidity detection unit 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 random 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 complement is set to be close to 0 when the humidity is low so that the intake air amount correction value is increased in the negative direction when the humidity is high. 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 small 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 ignition timing is adjusted so that the increased torque decreases as the amount of air increases.

  As a result, the torque of the engine 1 is stabilized, and fluctuations in the rotational speed of the engine 1 can be suppressed. In addition, even when auxiliary equipment such as an air conditioner is operated, in which the torque required to obtain a constant output changes due to a change in humidity when the engine 1 is in an idle state, fluctuations in the rotational speed of the engine 1 can be prevented. it can.

  The present invention is not limited to the above-described embodiment, but includes various modifications. For example, the above-described embodiment is described in detail to explain the present invention in an easy-to-understand manner, and is not necessarily limited to one having all the described configurations.

  Further, control lines and information lines indicate what is considered to be necessary for the description, and not all control lines and information lines in the product are necessarily shown. In practice, almost all configurations may be considered to be mutually connected.

1 ... Engine (internal combustion engine)
2 ... piston 3 ... intake valve 4 ... exhaust valve 5 ... fuel injection valve 6 ... ignition plug 7 ... ignition coil 9 ... ECU
DESCRIPTION OF SYMBOLS 10 ... Intake pipe 11 ... Exhaust pipe 12 Airflow sensor 15 ... Collector 16 ... Crank angle sensor 18 ... Control 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 Rotation speed calculator 302 Load calculator 303 Humidity detector 304 Air conditioner operation state detector (auxiliary machine operation state detection Department)
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)

An ignition timing control unit for controlling an ignition timing of the internal combustion engine to raise a temperature of a catalyst for purifying exhaust gas of the internal combustion engine and adjust a torque of the internal combustion engine;
An idle determination unit that determines whether the engine is in an idle state where the number of revolutions of the internal combustion engine is equal to or less than the upper limit threshold and equal to or greater than the lower limit threshold;
A humidity detection unit that detects the humidity of the air;
It is activated by an external input, wherein the torque while being driven by using the internal combustion engine, auxiliary machine the torque of the internal combustion engine required to obtain a constant output in response to the humidity of the air is changed An auxiliary machine operating state detecting unit for detecting the operating state of
An intake air amount determination unit that determines the amount of intake air to be drawn into the internal combustion engine based on the number of revolutions of the internal combustion engine, the torque of the internal combustion engine, and the output of the idle determination unit; A control device for an internal combustion engine, comprising: an intake air amount correction unit that corrects the intake air amount;
In the case where the idle determination unit determines that the vehicle is in the running state in the idle state, and the auxiliary device is activated after retarding control of the ignition timing of the internal combustion engine to raise the temperature of the catalyst,
The intake air amount correction unit corrects the intake air amount based on the output of the humidity detection unit,
By the ignition timing control unit for controlling so as to reduce the torque of the internal combustion engine is controlled based on the correction of the intake air amount by retarding the ignition timing, a predetermined target engine engine speed A control device for an internal combustion engine characterized by suppressing deviation of rotational speed. In the control device for an internal combustion engine according to claim 1,
The control apparatus for an internal combustion engine, wherein the intake air amount correction unit corrects the amount of intake air in a decreasing direction as the humidity of the air decreases. The control device for an internal combustion engine according to claim 1, wherein the accessory is an air conditioner.

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