JP2010168900A - Control device of engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a throttle valve from being seized at the fully closed position while the fully closed position is learned. <P>SOLUTION: When the temperature of a cooling water when an engine is stopped is lower than a preset predetermined temperature, the learning of the fully closed position of the throttle valve 6 is not performed. Though the deposit the viscosity of which is increased when the temperature is high is generated by the gas blown from the engine side (blowby gas, unburned gas, burned gas) and the particulates passing through an air cleaner 7 in the intake passage 2 of the engine 1, the learning of the fully closed position of the throttle valve 6 is prohibited when the viscosity of the deposit is high. Consequently, the seizure of the throttle valve due to the inclusion of the deposit can be suppressed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an engine control device.

  For example, Patent Document 1 states that when the engine is started, if the difference in cooling water temperature between the previous stop of the engine and the current start is equal to or less than a predetermined value, the output characteristics of the throttle opening sensor do not change. A technique that prohibits the learning of the fully closed position of the throttle valve is disclosed.

  In such a patent document 1, by reducing the number of times of learning of the reference position in the opening / closing control of the throttle valve, the durability of the mechanical system is improved while maintaining the reliability of learning, and the power consumption is suppressed. Can do.

  Further, in the intake passage, deposits are generated by blowback gas (blow-by gas, unburned gas, burned gas) from the engine side, fine particles that have passed through the air cleaner, and the like. Such deposits are known to increase in viscosity at low temperatures.

JP 2003-138971 A

  However, this Patent Document 1 does not determine whether or not the throttle valve fully closed position learning can be performed depending on the cooling water temperature, and whether or not the deposit is likely to be caught in the throttle valve during the fully closed position learning. No consideration is given. That is, in Patent Document 1, there is a possibility that learning of the fully closed position of the throttle valve is performed in a state where the viscosity of the deposit is high, and the throttle valve may be caught in the deposit and fixed in the fully closed position. is there.

  Therefore, the present invention is characterized in that the learning of the fully closed position of the throttle valve is not performed when the coolant temperature when the engine is stopped is lower than a predetermined temperature set in advance.

  In the engine intake passage, deposits that increase in viscosity at low temperatures are generated by blowback gas (blow-by gas, unburned gas, burned gas) from the engine side, and fine particles that have passed through the air cleaner. According to the present invention, when the deposit has a high viscosity, learning of the fully closed position of the throttle valve is prohibited, so that the throttle valve can be prevented from sticking due to the engagement of the deposit.

Explanatory drawing which showed typically schematic structure of the control apparatus of the engine which concerns on this invention The flowchart which shows the flow of control regarding the fully closed position learning of the throttle valve in 1st Embodiment of this invention. Explanatory drawing which showed typically the operation area | region where the flow volume of blow-by gas becomes large, and the operation area | region where the amount of EGR becomes large. The flowchart which shows the flow of control regarding the fully closed position learning of the throttle valve in 2nd Embodiment of this invention.

  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 schematic configuration of an engine control apparatus according to the present invention.

  An intake passage 2 and an exhaust passage 3 are connected to an engine 1 mounted on the vehicle as a drive source. An electronic control throttle valve (hereinafter referred to as a throttle valve) 6 whose opening degree is controlled via an actuator 5 by a control signal from an engine control unit (ECU) 4 is disposed in the intake passage 2. An air cleaner 7 is disposed on the upstream side of the throttle valve 6. A catalytic converter 8 for exhaust purification is disposed in the exhaust passage 3.

  The intake passage 2 and the exhaust passage 3 are connected to an EGR passage 10 in which an EGR valve 9 is interposed. One end of the EGR passage 10 is connected to the intake passage 2 on the downstream side of the throttle valve 6, and the other end is connected to the exhaust passage 3 on the upstream side of the catalytic converter 8. The EGR valve 9 is, for example, an electronically controlled type using a step motor, and its opening degree is controlled by a control signal from the ECU 4. That is, by controlling the opening degree of the EGR valve 9, the amount of exhaust gas recirculated to the intake side (exhaust gas recirculation amount), that is, the EGR amount sucked into the engine 1 is controlled.

  The ECU 4 includes a microcomputer that includes a CPU, a ROM, a RAM, an A / D converter, an input / output interface, and the like. The ECU 4 includes a throttle sensor 11 that detects the throttle opening of the throttle valve 6, a water temperature sensor 12 that detects the coolant temperature of the engine, a crank angle sensor 13 that detects the rotational speed of the engine, and an accelerator pedal depression amount by the driver. Signals are input from various sensors such as an accelerator opening sensor 14 for detecting the above. The ECU 4 receives a signal from a wheel rotation sensor 15 that detects the rotation of a wheel (not shown), and can accumulate and store the travel distance based on this signal. Then, the ECU 4 controls the engine 1 according to the operating conditions detected by these input signals.

  During idle operation, the ECU 4 performs idle rotation speed control that feedback-controls the intake air amount so that the engine rotation speed becomes a predetermined target idle rotation speed. During the execution of the idle rotation speed control, the control value of the intake air amount for obtaining the target idle rotation speed, that is, the control command value for the throttle valve 6 for obtaining the target idle rotation speed is learned as the idle intake air amount learning value. , Stored in the RAM in the ECU 4.

  When a predetermined condition is satisfied when the engine is stopped, the ECU 4 forcibly controls the throttle valve 6 to the fully closed position, and learns the output value of the throttle sensor 11 at this time as the fully closed position of the throttle valve 6.

  More specifically, deposits may be generated in the intake passage 2 by blowback gas (blow-by gas, unburned gas, burned gas) from the engine side, fine particles that have passed through the air cleaner 7, and the like. Since such a deposit increases in viscosity when the temperature is low, if the fully closed position learning of the throttle valve 6 is performed in a state where the viscosity of the deposit is high, the throttle valve 6 may be fixed due to the engagement of the deposit. . Further, when the cooling water temperature is low when the engine is stopped, it is considered that the vehicle has not traveled much since the previous trip, so that it is considered less necessary to learn the fully closed position of the throttle valve 6 again.

  Therefore, when the cooling water temperature is lower than a predetermined temperature (for example, 50 ° C.) set in advance when the engine is stopped, the fully closed position learning of the throttle valve 6 is not performed. In other words, when the engine temperature is stopped and the cooling water temperature is equal to or higher than a predetermined temperature (for example, 50 ° C.) set in advance, the fully closed position learning of the throttle valve 6 is performed.

  As a result, when the deposit viscosity is high, learning of the fully closed position of the throttle valve 6 is prohibited, so that the throttle valve 6 can be prevented from being stuck due to the engagement of the deposit.

  As the idle intake air amount learning value increases, the opening degree of the throttle valve 6 increases. In other words, it is considered that the larger the idle intake air amount learning value is, the larger the deposit amount is at the throttle valve position, and the smaller the idle intake air amount learning value is, the smaller the deposit amount is at the throttle valve position.

  Therefore, when the idle intake air amount learning value is smaller than a preset predetermined value when the engine is stopped, even when the cooling water temperature is lower than a preset predetermined temperature (for example, 50 ° C.), Considering that the amount of deposit deposited at the throttle valve position is small, the fully closed position learning of the throttle valve 6 is performed. Thereby, it is possible to prevent the learning frequency of the fully closed position of the throttle valve 6 from decreasing.

  In the initial state of the engine 1, deposits are not easily generated in the intake passage 2 of the engine 1, and the amount of deposits in the intake passage 2 is small. This is because deposits tend to be deposited in the intake passage 2, and the deposit deposition rate tends to increase, or the deterioration of oil (such as lubricating oil in blow-by gas) causes deposits to be deposited in the intake passage 2. This is because they tend to adhere (especially when oil contains a carbon component, it tends to adhere).

  Therefore, when the total travel distance of the vehicle using the engine 1 as a drive source is equal to or less than a predetermined distance (for example, 10,000 km) when the engine is stopped, the coolant temperature and the idle intake air amount learning value are set to the values. Regardless, the amount of deposit deposited at the throttle valve position is considered to be small, and the fully closed position learning of the throttle valve 6 is performed. Thereby, it is possible to prevent the learning frequency of the fully closed position of the throttle valve 6 from decreasing.

  Further, when the fully closed position learning of the throttle valve 6 is not continuously performed a predetermined number of times when the engine is stopped, the fully closed position learning of the throttle valve 6 is unconditionally performed at the next engine stop. Be sure to do it. Thereby, it is possible to prevent the learning frequency of the fully closed position of the throttle valve 6 from decreasing.

  FIG. 2 is a flowchart showing a flow of control related to learning of the fully closed position of the throttle valve 6 in the first embodiment described above.

  In step (hereinafter referred to as S) 11, it is determined whether or not the driver has operated the engine key to turn off the engine key. If it is determined that the engine key has been turned off and the engine has stopped, the process proceeds to S12. This routine is terminated.

  In S12, it is determined whether or not the total travel distance of the vehicle on which the engine 1 is mounted is larger than a predetermined value (for example, 10,000 km). If so, the process proceeds to S13, and if not, the process proceeds to S18. Proceed to

  In S13, it is determined whether or not the cooling water temperature is lower than a predetermined value (for example, 50 ° C.) set in advance. If it is lower, the process proceeds to S14, and if not, the process proceeds to S18.

  In S14, it is determined whether or not the idle intake air amount learning value is greater than or equal to a predetermined value. If it is greater than or equal to the predetermined value, the process proceeds to S15, and if not, the process proceeds to S18.

  In S15, it is determined whether the fully closed position learning failure counter (LNC) of the throttle valve 6 is smaller than a predetermined number of times set in advance. If it is smaller, the process proceeds to S16, and if not, the process proceeds to S18. That is, if the fully closed position learning of the throttle valve 6 has not been performed continuously for a predetermined number of preset times, the process proceeds to S18, and if not, the process proceeds to S16.

  In S16, the fully closed position learning of the throttle valve 6 is not performed, and the process proceeds to S17. In S17, a fully closed position learning failure counter (LNC) is incremented by one.

  In S18, learning of the fully closed position of the throttle valve 6 is performed, and the process proceeds to S19. In S19, the fully closed position learning failure counter (LNC) is reset.

  Hereinafter, although other embodiment of this invention is described, about the component same as 1st Embodiment mentioned above, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

  Next, a second embodiment of the present invention will be described. This second embodiment has substantially the same configuration as the first embodiment described above, but in order to ensure the learning frequency of the fully closed position of the throttle valve 6, the determination using the idle intake air amount learning value is performed. Instead, if the operating conditions are such that deposits are difficult to generate, even if the cooling water temperature is lower than a predetermined temperature (for example, 50 ° C.), the deposit amount at the throttle valve position is considered to be small. The fully closed position learning of the throttle valve 6 is performed.

  Under operating conditions where the flow rate of blow-by gas and the amount of EGR increase, deposits are likely to be generated in the intake passage 2.

  As shown in FIG. 3, when the operating condition is high torque (high load, that is, the fuel injection amount is large), the flow rate of blow-by gas becomes large, and low torque (low load, that is, the fuel injection amount is small) and low rotation. The amount of EGR becomes large under the operating conditions.

  Therefore, in the second embodiment, it is determined whether or not it is an operating condition in which it is difficult to generate a deposit by using the engine rotation speed and the fuel injection amount, and the driving immediately before the engine is stopped is in an operating condition in which it is difficult to generate a deposit. If there is, learning of the fully closed position of the throttle valve 6 is performed regardless of the coolant temperature. That is, using the engine speed and the fuel injection amount, it is determined whether the operating condition is that the EGR amount is large or the blow-by gas flow rate is large.

  More specifically, in the operation immediately before the engine is stopped, the value EGRRSTCTW obtained by multiplying the integrated value EGRRSTCT of the number of times of deceleration from the operation region where the EGR amount is large (the definition will be described later) and the blowby gas flow rate is large. When the sum of the number of times of deceleration (the definition will be described later) and the value BBYSTCTW obtained by multiplying the contribution value by the contribution value BBYSTCT is smaller than a predetermined value set in advance, the throttle valve 6 is fully closed regardless of the coolant temperature. Conduct learning.

  Here, the number of times of deceleration described above represents the number of times of deceleration when an accelerator fully closed signal is input from each operation region. This is because when the throttle valve 6 is closed by the accelerator fully closed signal, the pressure on the intake passage 2 side becomes lower than in the engine 1, and blow-by gas or EGR gas (exhaust gas) blows back toward the throttle valve 6. The number of times of deceleration is taken into consideration because it becomes particularly strong and deposits are particularly easily attached around the throttle valve 6. The contribution is set so that the contribution of the EGR amount is larger than the contribution of the blow-by gas flow rate. This is because the EGR amount contributes more to the deposit generation than the blow-by gas flow rate.

  In the second embodiment as well, as in the first embodiment described above, the throttle valve 6 is prevented from sticking due to the engagement of the deposit when learning the fully closed position of the throttle valve 6. The learning frequency of the fully closed position can be ensured.

  FIG. 4 is a flowchart showing a flow of control related to learning of the fully closed position of the throttle valve 6 in the second embodiment described above.

  In S21, it is determined whether or not the driver has operated the engine key to turn off the engine key. If it is determined that the engine key has been turned off and the engine has stopped, the process proceeds to S22. If not, the current routine is terminated.

  In S22, it is determined whether or not the total travel distance of the vehicle on which the engine 1 is mounted is larger than a predetermined value (for example, 10,000 km). If so, the process proceeds to S23, and if not, the process proceeds to S28. Proceed to

  In S23, it is determined whether or not the cooling water temperature is lower than a predetermined value (for example, 50 ° C.) set in advance. If it is lower, the process proceeds to S24, and if not, the process proceeds to S28.

  In S24, it is determined whether or not the operating condition is such that it is difficult to generate a deposit by using the engine speed and the fuel injection amount. More specifically, the value EGRSTCTW obtained by multiplying the contribution value by the integrated value EGRSTCT of the number of times of deceleration from the operation region where the EGR amount is large and the sum value BBYSTCT of the number of times of deceleration from the operation region where the blowby gas flow rate is large are multiplied by the contribution degree. It is determined whether or not the sum of the calculated value BBYSTCTW is larger than a predetermined value set in advance, the process proceeds to S25 if it is greater, otherwise proceeds to S28.

  In S25, it is determined whether the fully closed position learning failure counter (LNC) of the throttle valve 6 is smaller than a predetermined number of times set in advance. If it is smaller, the process proceeds to S26, and if not, the process proceeds to S28. That is, if the fully closed position learning of the throttle valve 6 has not been continuously performed for a predetermined number of times, the process proceeds to S28, and if not, the process proceeds to S26.

  In S26, the fully closed position learning of the throttle valve 6 is not performed, and the process proceeds to S27. At S27, the fully closed position learning failure counter (LNC) is incremented by one.

  In S28, the fully closed position learning of the throttle valve 6 is performed, and the process proceeds to S29. In S29, the fully closed position learning failure counter (LNC) is reset.

  In the second embodiment, an operating condition in which deposits are likely to be generated in the intake passage 2 using the sum of the value EGRSTCTW obtained by multiplying the integrated value EGRSTCT by the contribution and the value BBYSTCTW obtained by multiplying the accumulated value BBYSTCT by the contribution. However, it is also possible to calculate the EGR amount and the blow-by gas flow rate to determine whether the operating conditions are such that deposits are likely to be generated in the intake passage 2. The EGR amount can be calculated from, for example, the opening command value of the EGR valve 9, and the blow-by gas flow rate can be calculated from, for example, a map stored in the ECU 4 in advance using the fuel injection amount and the engine speed. It can be calculated by reading.

  Further, as an operating condition in which deposits are difficult to be generated, when the integrated value of the EGR amount up to the present is equal to or less than a predetermined value set in advance, it is determined that the operating conditions are such that deposits are not easily generated in the intake passage 2. It is also possible to make it.

  In the first and second embodiments described above, the total mileage of the vehicle is used as an index for determining the initial state of the engine 1, but the initial state of the engine 1 is replaced with the total mileage of the vehicle. You may make it use the total operation time of the engine 1 as a parameter | index to determine. That is, when the engine is stopped and the total operation time of the engine 1 is equal to or less than a predetermined time set in advance, the amount of deposit deposited at the throttle valve position is independent of the values of the coolant temperature and the idle intake air amount learning value. Even if it is considered that the number of fully closed positions of the throttle valve 6 is learned, the learning frequency of the fully closed position of the throttle valve 6 can be prevented from decreasing. Here, the total operation time of the engine 1 may be stored in the RAM of the ECU 4 by providing a timer in the ECU 4, for example.

  In addition, the present invention is not limited to the first and second embodiments described above, and permits the learning of the fully closed position of the throttle valve 6 by combining the various determination elements described above alone or appropriately. It may be.

  For example, it may be determined whether or not learning of the fully closed position of the throttle valve 6 is permitted using only the coolant temperature when the engine is stopped. Specifically, whether or not learning of the fully closed position of the throttle valve 6 can be performed may be determined based on the control flow in which S12, S14, S15, S17, and S19 are deleted in FIG.

  Further, for example, when the coolant temperature is lower than a predetermined temperature (for example, 50 ° C.) set in advance when the engine is stopped, the fully closed position learning of the throttle valve 6 is not performed, but when the engine is stopped, the throttle valve 6 When the fully closed position learning is not continuously performed for a predetermined number of times, the fully closed position learning of the throttle valve 6 may be performed unconditionally at the next engine stop. Specifically, whether or not learning of the fully closed position of the throttle valve 6 can be performed may be determined based on the control flow in which S12 and S14 are deleted in FIG.

  The present invention is also applicable to an idle stop vehicle that automatically stops the engine when the vehicle is temporarily stopped. In this case, the throttle valve fully closed position learning can be performed even when the predetermined condition as in each of the above-described embodiments is satisfied when the engine is stopped by the idle stop.

  The technical ideas of the present invention that can be grasped from the above-described embodiments will be listed together with their effects.

  (1) A throttle valve provided in an intake passage of the engine, a throttle sensor that detects an opening of the throttle valve, and a water temperature sensor that detects a cooling water temperature of the engine, and the throttle valve when the engine is stopped In the engine control apparatus that performs learning of the fully closed position, learning of the fully closed position of the throttle valve is not performed when the coolant temperature when the engine is stopped is lower than a predetermined temperature set in advance. In the intake passage of the engine, deposits are generated by blowback gas (blow-by gas, unburned gas, burned gas) from the engine side, fine particles that have passed through the air cleaner, and the like. Such deposits increase in viscosity at low temperatures. Accordingly, when the deposit viscosity is high, learning of the fully closed position of the throttle valve is prohibited, so that the throttle valve can be prevented from sticking due to the engagement of the deposit.

  (2) The engine control apparatus according to (1), further including a travel distance detection unit that detects a travel distance of a vehicle using the engine as a drive source, and the total travel distance of the vehicle is preset when the engine is stopped. If the distance is less than the predetermined distance, learning of the fully closed position of the throttle valve is performed regardless of the coolant temperature. In the initial state of the engine, deposits are not easily generated in the intake passage of the engine, and the amount of deposits is small. As a result, it is possible to prevent a decrease in the learning frequency of the fully closed position of the throttle valve.

  (3) In the engine control device according to (1) or (2), if learning of the fully closed position of the throttle valve has not been continuously performed a predetermined number of times, the next engine When stopping, learning of the fully closed position of the throttle valve is performed regardless of the coolant temperature. As a result, it is possible to prevent a decrease in the learning frequency of the fully closed position of the throttle valve.

  (4) The engine control device according to any one of (1) to (3), further including an operation time detection unit that detects a total operation time of the engine, and the engine operation time when the engine is stopped. Is less than a predetermined time set in advance, learning of the fully closed position of the throttle valve is performed regardless of the coolant temperature. In the initial state of the engine, deposits are not easily generated in the intake passage of the engine, and the amount of deposits is small. As a result, it is possible to prevent a decrease in the learning frequency of the fully closed position of the throttle valve.

  (5) In the engine control device according to any one of (1) to (4), when the engine is idling, the amount of intake air is adjusted so that the engine rotation speed becomes a predetermined target idle rotation speed. Idle rotation speed control for feedback control, comprising idle intake air amount learning means for learning a control value of the intake air amount when the target idle rotation speed is obtained as an idle intake air amount learning value, If the current idle intake air amount learning value is smaller than a predetermined value when the engine is stopped, learning of the fully closed position of the throttle valve is performed regardless of the coolant temperature. The larger the idle intake air amount learning value, the larger the opening of the throttle valve. That is, it is considered that the larger the idle intake air amount learning value is, the larger the deposit amount is at the throttle valve position. As a result, it is possible to prevent a decrease in the learning frequency of the fully closed position of the throttle valve.

  (6) In the engine control device according to any one of (1) to (5), if the operating condition is such that deposits are not easily generated in the intake passage, the engine is stopped regardless of the cooling water temperature. Learning about the fully closed position of the throttle valve. As a result, it is possible to prevent a decrease in the learning frequency of the fully closed position of the throttle valve.

  (7) Specifically, the engine control device according to (6) determines whether or not the operating condition is such that a deposit is not easily generated using the engine rotation speed and the fuel injection amount.

  (8) The engine control device according to (6), specifically, the exhaust gas recirculation means for returning a part of the exhaust gas flowing through the exhaust passage to the intake air passage, and the intake air passage via the exhaust gas recirculation means. And an exhaust gas recirculation amount detecting means for detecting the exhaust gas recirculation amount that has been recirculated to the exhaust passage, and when the integrated value of the exhaust gas recirculation amount is equal to or less than a predetermined value, the operating condition before the engine is stopped is an intake passage. It is determined that the operating conditions are difficult to generate deposits.

DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Intake passage 3 ... Exhaust passage 4 ... ECU
5 ... Actuator 6 ... Electronically controlled throttle valve 8 ... Catalytic converter 9 ... EGR valve 10 ... EGR passage

Claims (8)

A throttle valve provided in an intake passage of the engine; a throttle sensor that detects an opening of the throttle valve; and a water temperature sensor that detects a cooling water temperature of the engine, and the throttle valve is fully closed when the engine is stopped. In an engine control device that performs position learning,
An engine control device characterized by not learning the fully closed position of the throttle valve when the cooling water temperature when the engine is stopped is lower than a predetermined temperature set in advance.   The vehicle has a mileage detecting means for detecting the mileage of the vehicle using the engine as a drive source, and when the total mileage of the vehicle is equal to or less than a predetermined distance when the engine is stopped, regardless of the coolant temperature. The engine control device according to claim 1, wherein learning of a fully closed position of the throttle valve is performed.   If learning of the fully closed position of the throttle valve has not been performed continuously for a predetermined number of times, learning of the fully closed position of the throttle valve is performed at the next engine stop regardless of the coolant temperature. The engine control device according to claim 1, wherein the engine control device is an engine control device.   The throttle valve has an operation time detecting means for detecting the total operation time of the engine, and when the engine is stopped, when the total operation time of the engine is not more than a predetermined time set in advance, the throttle valve The engine control apparatus according to claim 1, wherein learning of the fully closed position is performed. During idle operation of the engine, idle rotation speed control is performed to feedback control the intake air amount so that the engine rotation speed becomes a predetermined target idle rotation speed, and the target idle rotation speed is obtained. Idle intake air amount learning means for learning the control value of the intake air amount as an idle intake air amount learning value,
When the engine is stopped and the current idle intake air amount learning value is smaller than a predetermined value set in advance, learning of the fully closed position of the throttle valve is performed regardless of the coolant temperature. The engine control device according to any one of claims 1 to 4.   6. The fully closed position of the throttle valve is learned regardless of the cooling water temperature when the engine is stopped under an operating condition in which deposits are difficult to be generated in the intake passage. Engine control device according to   7. The engine control apparatus according to claim 6, wherein it is determined whether or not the operating condition is such that a deposit is difficult to be generated using the engine speed and the fuel injection amount. Exhaust recirculation means for recirculating a part of the exhaust gas flowing through the exhaust passage to the intake passage, and exhaust recirculation amount detection means for detecting the exhaust recirculation amount recirculated to the intake passage via the exhaust recirculation means,
When the integrated value of the exhaust gas recirculation amount is equal to or less than a predetermined value set in advance, it is determined that the operating condition before the engine is stopped is an operating condition in which deposit is not easily generated in the intake passage. 6. The engine control device according to 6.

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