JP2013087624A - Ignition control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further efficiently output power from an internal combustion engine, by restraining the ignition timing of the internal combustion engine from being delayed accidentally at a low temperature time.SOLUTION: At low temperature time when the cooling water temperature Tw of an engine is less than a predetermined temperature threshold value Twref, a low temperature time learning value Tfl2 for the low temperature time is updated based on a knock correction quantity Tfc in a range of not becoming a value on the side for delaying the ignition timing of the engine more than an ordinary time learning value Tfl1 at an ordinary time when the cooling water temperature Tw is the temperature threshold value Twref or more, and the target ignition timing Tf* is set by making a correction by the knock correction quantity Tfc and the low temperature time learning value Tfl2 to the reference ignition timing Tfb. Thus, the ignition timing of the engine is restrained from being delayed accidentally at the low temperature time, and torque can be further efficiently output from the engine.

Description

  The present invention relates to an ignition control device for an internal combustion engine. The target is obtained by performing correction using a knock correction amount that is increased or decreased according to the occurrence of occurrence, and a learning value that is updated based on the knock correction amount so that the knock correction amount is constantly reflected in the ignition timing of the internal combustion engine. The present invention relates to an ignition control device for an internal combustion engine, which sets an ignition timing and controls the internal combustion engine so that the internal combustion engine is ignited at the set target ignition timing.

  Conventionally, as an ignition control device for an internal combustion engine of this type, a retard correction amount for avoiding knocking in an internal combustion engine is learned as a learning value only when it is determined that the internal combustion engine is at a temperature higher than a first set temperature. And calculating the ignition timing based on the stored learned value and the operating state of the internal combustion engine has been proposed (for example, see Patent Document 1). In this device, the history of the past correction amount of the ignition timing when the temperature of the internal combustion engine is higher than the first set temperature is utilized in the calculation of the current ignition timing.

JP-A-62-93484

  However, in the above-described apparatus, when the temperature of the internal combustion engine is low, the retard correction amount for avoiding knocking is not learned, so the ignition timing of the internal combustion engine is set to a value on the retard side within a range where knocking is avoided. There is a case where the ignition timing of the internal combustion engine can be set to a more advanced timing within a range where knocking is avoided, that is, power can be efficiently output from the internal combustion engine within a range where knocking is avoided. There was room for it. Further, when the temperature of the internal combustion engine is low, for example, noise generated between the piston and the cylinder inner wall is erroneously detected as knocking, although knocking is less likely to occur than when the temperature of the internal combustion engine is low. For example, the amount of retardation correction for avoiding knocking may become a large value on the retard side by mistake.

  An ignition control device for an internal combustion engine according to the present invention is mainly intended to prevent the ignition timing of the internal combustion engine from being delayed accidentally at low temperatures and to output power more efficiently from the internal combustion engine.

  The internal combustion engine ignition control apparatus according to the present invention employs the following means in order to achieve the main object described above.

The internal combustion engine ignition control device of the present invention,
A knock correction amount that is increased or decreased according to the presence or absence of the knock so that the ignition timing of the internal combustion engine is advanced within a range in which the knock in the internal combustion engine is suppressed with respect to a reference ignition timing based on the operating state of the internal combustion engine And a learning value that is updated based on the knock correction amount so that the knock correction amount is constantly reflected in the ignition timing of the internal combustion engine. And an ignition control device for controlling the internal combustion engine so that the internal combustion engine is ignited at the set target ignition timing,
The target ignition timing setting means is the learning value for normal time when the temperature of the coolant is equal to or higher than the temperature threshold at a low temperature when the temperature of the coolant that cools the internal combustion engine is lower than a predetermined temperature threshold. The learning value for the low temperature is updated based on the knock correction amount within a range that does not become a value on the side of retarding the ignition timing of the internal combustion engine, and the knock correction amount and the reference value for the reference ignition timing are updated. The target ignition timing is set by performing correction with the learning value for low temperature,
This is the gist.

  In the internal combustion engine ignition control device according to the present invention, at a low temperature when the temperature of the coolant for cooling the internal combustion engine is lower than a predetermined temperature threshold, the learning value for normal time when the temperature of the coolant is equal to or higher than the temperature threshold. The learning value for the low temperature is updated based on the knock correction amount within a range that does not become the value for retarding the ignition timing of the internal combustion engine, and the knock correction amount and the learning value for the low temperature are compared with the reference ignition timing. The target ignition timing is set by performing correction according to the above. As a result, learning about the ignition timing of the internal combustion engine can be performed even at low temperatures, and the target ignition timing can be set using the learning value for low temperatures, and power can be output more efficiently from the internal combustion engine at low temperatures. . In addition, even if the knock correction amount is erroneously delayed at low temperatures, the learning value for low temperatures does not become the value for retarding the ignition timing from the learning value for normal times. Sometimes, it is possible to prevent the ignition timing of the internal combustion engine from being delayed accidentally. As a result, it is possible to prevent the ignition timing of the internal combustion engine from being delayed accidentally at low temperatures and to output power more efficiently from the internal combustion engine. In this case, the target ignition timing setting means corrects the reference ignition timing with the knock correction amount and the learning value for the normal time based on the knock correction amount with respect to the reference ignition timing. It is also possible to be a means for setting.

  Here, the reference ignition timing is the ignition timing of the internal combustion engine within a range in which knocking does not occur even under predetermined environmental conditions where knocking is likely to occur based on the rotational speed and volumetric efficiency of the internal combustion engine (for example, predetermined environmental conditions). Also, the ignition timing of the internal combustion engine that is the earliest within a range in which knocking does not occur can be set. In addition, the knock correction amount is changed by a first predetermined amount toward the side that accelerates the ignition timing of the internal combustion engine when knocking does not occur, and the first position when the ignition timing of the internal combustion engine is delayed when knocking occurs. It may be set by changing a second predetermined amount that is larger than the fixed amount and according to the size of the knock. Further, the occurrence of knocking can be determined based on whether or not the knock intensity is equal to or higher than a knock determination threshold value based on the operating state of the internal combustion engine. Further, the learning value may be updated to the value of the knock correction amount when the fluctuation amount of the knock correction amount within a predetermined time becomes less than the predetermined amount (contains). Further, the temperature threshold may be a temperature indicating a state in which the internal combustion engine is warmed up.

  In such an ignition control device for an internal combustion engine according to the present invention, when the target ignition timing setting means updates the learning value for the low temperature based on the knock correction amount at the low temperature, the learning value for the low temperature Is a means for holding the learning value for the low temperature without updating when the ignition timing of the internal combustion engine is delayed from the learning value for the normal time. it can. In this way, it is possible to ensure that the learning value for the low temperature does not become a value on the side that makes the ignition timing later than the learning value for the normal time.

  In the ignition control device for an internal combustion engine according to the present invention, the learning value may be calculated for each region obtained by dividing the operation region of the internal combustion engine (region in which the internal combustion engine can be operated) into at least a plurality of loads of the internal combustion engine. The value may be updated based on the knock correction amount. In this way, the learning value for normal time and the learning value for low temperature can be updated more appropriately, and the target ignition timing can be set more appropriately.

1 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 20 equipped with an ignition control device for an internal combustion engine as one embodiment of the present invention. 2 is a configuration diagram showing an outline of the configuration of an engine 22. FIG. 3 is a flowchart showing an example of an ignition control routine executed by an engine ECU 24. It is explanatory drawing which shows an example of a mode that the learning value for normal time Tfl1 is updated. It is explanatory drawing which shows an example of a mode that the learning value for low temperature use Tfl2 is updated.

  Next, the form for implementing this invention is demonstrated using an Example.

  FIG. 1 is a configuration diagram showing an outline of the configuration of a hybrid vehicle 20 equipped with an internal combustion engine ignition control device according to an embodiment of the present invention. As shown in the figure, the hybrid vehicle 20 of the embodiment includes an engine 22 as an internal combustion engine, an engine electronic control unit (hereinafter referred to as an engine ECU) 24 that controls the drive of the engine 22, and a crankshaft 26 of the engine 22 with a carrier. And a planetary gear 30 in which a ring gear is connected to a drive shaft 36 connected to the drive wheels 38a and 38b via a differential gear 37, and a rotor connected to the sun gear of the planetary gear 30. A motor MG1 configured as a synchronous generator motor, for example, a motor MG2 having a rotor connected to the drive shaft 36, inverters 41 and 42 for driving the motors MG1 and MG2 by switching of a plurality of switching elements (not shown), Of inverters 41 and 42 A motor electronic control unit (hereinafter referred to as a motor ECU) 40 that controls the motors MG1 and MG2 by switching control of a number of switching elements, and a lithium ion secondary battery, for example, are connected via inverters 41 and 42. A battery 50 that exchanges power with the motors MG1, MG2, a battery electronic control unit (hereinafter referred to as a battery ECU) 52 that manages the battery 50, and a hybrid electronic control unit (hereinafter referred to as an HVECU) 70 that controls the entire vehicle. And comprising. Here, the engine ECU 24 mainly corresponds to the ignition control device of the internal combustion engine of the embodiment.

  The engine 22 is configured as an internal combustion engine capable of outputting power using a hydrocarbon-based fuel such as gasoline or light oil, and the air purified by an air cleaner 122 is passed through a throttle valve 124 as shown in FIG. Inhalation and gasoline are injected from the fuel injection valve 126 to mix the sucked air and gasoline, and this mixture is sucked into the combustion chamber through the intake valve 128 and explosively burned by an electric spark from the spark plug 130. Thus, the reciprocating motion of the piston 132 pushed down by the energy is converted into the rotational motion of the crankshaft 26. Exhaust gas from the engine 22 is discharged to the outside air through a purification device (three-way catalyst) 134 that purifies harmful components such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx).

  The engine ECU 24 is configured as a microprocessor centered on the CPU 24a, and in addition to the CPU 24a, a ROM 24b that stores processing programs, a RAM 24c that temporarily stores data, and a nonvolatile flash memory that holds the stored data 24d and input / output ports and communication ports (not shown). The engine ECU 24 includes signals from various sensors that detect the state of the engine 22, a crank position θcr from the crank position sensor 140 that detects the rotational position of the crankshaft 26, and a water temperature sensor that detects the temperature of cooling water in the engine 22. The cooling water temperature Tw from 142, the in-cylinder pressure Pin from the pressure sensor 143 attached in the combustion chamber, the rotation of the intake cam shaft for opening and closing the intake valve 128 for intake and exhaust to the combustion chamber, and the rotation of the exhaust cam shaft for opening and closing the exhaust valve An air flow meter 14 for detecting a cam angle from a cam position sensor 144 for detecting a position, a throttle opening TH from a throttle valve position sensor 146 for detecting a position of a throttle valve 124, and a mass flow rate of intake air attached to an intake pipe. From the temperature sensor 149 that detects the temperature of the three-way catalyst of the purifier 134, and the exhaust air amount Qa from the temperature sensor 149 attached to the exhaust system. The air-fuel ratio AF from the air-fuel ratio sensor 135a, the oxygen signal O2 from the oxygen sensor 135b attached to the exhaust system, the intake pressure Pi from the pressure sensor 158 for detecting the pressure in the intake pipe, the knocking attached to the cylinder block A knock signal Ks or the like from a knock sensor 159 that detects a vibration caused by the generation is input via an input port. The engine ECU 24 is integrated with various control signals for driving the engine 22, such as a drive signal for the fuel injection valve 126, a drive signal for the throttle motor 136 that adjusts the position of the throttle valve 124, and an igniter. Further, a control signal to the ignition coil 138, a control signal to the variable valve timing mechanism 150 capable of changing the opening / closing timing VT of the intake valve 128, and the like are output via the output port. The engine ECU 24 is in communication with the HVECU 70, controls the operation of the engine 22 by a control signal from the HVECU 70, and outputs data related to the operation state of the engine 22 as necessary. The engine ECU 24 calculates the rotational speed of the crankshaft 26, that is, the rotational speed Ne of the engine 22 based on a signal from the crank position sensor 140 attached to the crankshaft 26, and the intake air amount from the air flow meter 148. Based on Qa and the rotational speed Ne of the engine 22, the volume efficiency as the load factor of the engine 22 (ratio of the volume of air actually sucked in one cycle to the stroke volume per cycle of the engine 22) KL is calculated. Or the open / close timing VT of the intake valve 128 is calculated based on the angle (θci−θcr) of the intake camshaft cam angle θci of the intake valve 128 from the cam position sensor 144 to the crank angle θcr from the crank position sensor 140. , From knock sensor 159 Based on the size and waveform of the click signal Ks are or calculating the knock intensity Kr indicating the occurrence level of knocking.

  Although not shown, the motor ECU 40 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. . The motor ECU 40 receives signals necessary for driving and controlling the motors MG1 and MG2, for example, rotational positions θm1 and θm2 from rotational position detection sensors 43 and 44 that detect the rotational positions of the rotors of the motors MG1 and MG2, and not shown. A phase current applied to the motors MG1 and MG2 detected by the current sensor is input via the input port, and the motor ECU 40 outputs a switching control signal to switching elements (not shown) of the inverters 41 and 42. It is output through the port. The motor ECU 40 is in communication with the HVECU 70, controls the driving of the motors MG1 and MG2 by a control signal from the HVECU 70, and outputs data related to the operating state of the motors MG1 and MG2 to the HVECU 70 as necessary. The motor ECU 40 also calculates the rotational angular velocities ωm1, ωm2 and the rotational speeds Nm1, Nm2 of the motors MG1, MG2 based on the rotational positions θm1, θm2 of the rotors of the motors MG1, MG2 from the rotational position detection sensors 43, 44. ing.

  Although not shown, the battery ECU 52 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. . The battery ECU 52 receives signals necessary for managing the battery 50, for example, an inter-terminal voltage Vb from a voltage sensor (not shown) installed between the terminals of the battery 50 and a power line connected to the output terminal of the battery 50. The charging / discharging current Ib from the attached current sensor (not shown), the battery temperature Tb from the temperature sensor (not shown) attached to the battery 50, and the like are input. Send to. Further, in order to manage the battery 50, the battery ECU 52 is a power storage that is a ratio of the capacity of the electric power that can be discharged from the battery 50 at that time based on the integrated value of the charge / discharge current Ib detected by the current sensor. The ratio SOC is calculated, and the input / output limits Win and Wout, which are the maximum allowable power that may charge / discharge the battery 50, are calculated based on the calculated storage ratio SOC and the battery temperature Tb.

  Although not shown, the HVECU 70 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. The HVECU 70 includes an ignition signal from the ignition switch 80, a shift position SP from the shift position sensor 82 that detects the operation position of the shift lever 81, and an accelerator opening degree from the accelerator pedal position sensor 84 that detects the amount of depression of the accelerator pedal 83. Acc, the brake pedal position BP from the brake pedal position sensor 86 that detects the depression amount of the brake pedal 85, the vehicle speed V from the vehicle speed sensor 88, and the like are input via the input port. Further, as described above, the HVECU 70 is connected to the engine ECU 24, the motor ECU 40, and the battery ECU 52 via the communication port, and exchanges various control signals and data with the engine ECU 24, the motor ECU 40, and the battery ECU 52.

  In the hybrid vehicle 20 of the embodiment thus configured, the required torque Tr * to be output to the drive shaft 36 is set based on the accelerator opening Acc and the vehicle speed V corresponding to the amount of depression of the accelerator pedal by the driver, An engine in which the required power Pe * to be output from the engine 22 is set based on the required torque Tr * and the charge / discharge required power of the battery 50 and the required power Pe * is greater than or equal to a threshold or the storage ratio SOC of the battery 50 is less than the threshold. When the operating condition 22 is satisfied, the engine 22 is operated at a target operating point consisting of a target rotational speed Ne * and a target torque Te * as an operating point for efficiently outputting the required power Pe * from the engine 22. The engine 22 and the motor M so that the required power corresponding to the required torque Tr * is output to the drive shaft 36. 1 and the motor MG2 are controlled to operate, and when the operating condition of the engine 22 is not satisfied, the motor MG2 outputs the power corresponding to the required power from the motor MG2 to the drive shaft 36 while the operation of the engine 22 is stopped. Operation is controlled.

  In the operation control of the engine 22, in the embodiment, the target throttle opening TH * and the target opening / closing of the intake valve 128 for efficiently operating the engine 22 at the target operation point composed of the target rotational speed Ne * and the target torque Te *. The timing VT * is set, and the target fuel injection amount Qf * for obtaining the target air-fuel ratio such as the stoichiometric air-fuel ratio based on the rotational speed Ne of the engine 22 and the volumetric efficiency KL and the occurrence of knocking in the engine 22 are suppressed. The target ignition timing Tf * for setting the ignition timing of the engine 22 within a predetermined range is set. Then, the intake air amount control is performed by controlling the throttle motor 136 so that the throttle opening TH of the throttle valve 124 becomes the target throttle opening TH *, and the opening / closing timing VT of the intake valve 128 is set to the target opening / closing timing VT *. Open / close timing control is performed by controlling the drive of the variable valve timing mechanism 150, and fuel injection control is performed by controlling the fuel injection valve 126 so that fuel is injected at the target fuel injection amount Qf *. The ignition control is performed by driving the ignition coil 138 so as to perform ignition at the target ignition timing Tf *. Hereinafter, making the ignition timing of the engine 22 earlier and later is also referred to as “advance” and “retard”, respectively.

  Next, the operation of the engine 22 in the hybrid vehicle 20 of the embodiment, particularly the operation when performing ignition control of the engine 22 will be described. FIG. 3 is a flowchart showing an example of an ignition control routine executed by the engine ECU 24. This routine is repeatedly executed every predetermined time.

  When the ignition control routine is executed, the CPU 24a of the engine ECU 24 first executes processing for inputting data necessary for control such as the rotational speed Ne of the engine 22, the cooling water temperature Tw, the volumetric efficiency KL, and the knock determination flag F ( Step S100). Here, the rotation speed Ne of the engine 22 is input as a value calculated based on a signal from the crank position sensor 140. The volume efficiency KL of the engine 22 is calculated based on the intake air amount Qa from the air flow meter 148 and the rotational speed Ne of the engine 22. The knock determination flag F is a flag indicating whether or not a knock has occurred in the engine 22. In the embodiment, the knock magnitude Kr calculated based on the knock signal Ks from the knock sensor 159 and the knock determination threshold value Kref When the knock magnitude Kr is equal to or less than the knock determination threshold value Kref, it is determined that the knock generation level is within the allowable range and no knock has occurred, and the value 0 is set. The knock intensity Kr is determined from the knock determination threshold value Kref. When the value is large, the knock generation level exceeds the allowable range and it is determined that the knock has occurred, and a value set to 1 is input. The knock determination threshold value Kref is used to determine whether or not the knock generation level is within an allowable range. In the embodiment, the relationship between the rotational speed Ne of the engine 22, the intake pressure Pi, and the knock determination threshold value Kref. Is set by applying the current rotational speed Ne and the intake pressure Pi to a map determined in advance through experiments or the like.

  When the data is input in this way, the reference ignition timing Tfb of the engine 22 is set based on the input engine speed Ne and the volumetric efficiency KL (step S110). In the embodiment, the reference ignition timing Tfb is an ignition timing within a range in which knocking does not occur in the engine 22 even under predetermined environmental conditions such as temperature, humidity, fuel type, etc. The ignition timing on the most advanced side within a range in which knock does not occur in a predetermined environmental condition in which the fuel having the lowest octane number is used, and the rotational speed Ne, the volumetric efficiency KL, and the reference ignition timing Tfb The relationship is determined in advance in an experiment or the like and stored as a map in the ROM 24b. When the rotational speed Ne and the volumetric efficiency KL are given, the corresponding reference ignition timing Tfb is derived and set from the map.

  Subsequently, the input knock determination flag F is checked (step S120). When the knock determination flag F is 0, it is determined that the ignition timing of the engine 22 may be advanced, and depending on whether knock has occurred or not. A knock correction amount Tfc for correcting the ignition timing is calculated as the sum of the knock correction amount Tfc (previous Tfc) calculated when the routine was executed last time and a predetermined advance amount ΔTfc1 (step S130). When the knock determination flag F is 1, the ignition timing of the engine 22 is determined to be greatly retarded, and the predetermined retardation amount ΔTfc2 that is greater than the predetermined advance amount ΔTfc1 from the previous Tfc and that corresponds to the knock strength Kr. Is calculated as a knock correction amount Tfc (step S140). In the embodiment, the direction in which the ignition timing of the engine 22 is advanced is a positive direction and the direction in which the ignition timing is retarded is a negative direction, and positive values are used as the predetermined advance amount ΔTfc1 and the predetermined retard amount ΔTfc2. It was supposed to be used. The predetermined retardation amount ΔTfc2 corresponding to the knock magnitude Kr is, for example, a retard quantity that increases as the knock magnitude Kr is greater than the knock judgment threshold Kref, or a knock judgment within a certain time until the knock magnitude Kr is reached. It is possible to use a retard amount that tends to increase as the number of times the threshold value Kref becomes larger. The target ignition timing Tf * as the target value of the ignition timing of the engine 22 is knocked so that the reference ignition timing Tfb, the knock correction amount Tfc, and the knock correction amount Tfc are constantly reflected in the ignition timing, as will be described later. It is calculated as the sum of the learning value updated based on the correction amount Tfc. Therefore, considering that the learning value that is not learned based on the knock correction amount Tfc is 0, the target ignition timing Tf * is gradually advanced by a predetermined advance amount ΔTf1 and knocking occurs. In some cases, after being delayed a plurality of times by a predetermined retardation amount ΔTf2, the value is converged to a more advanced value within a range where knock does not occur. Note that the learning value is updated based on the knock correction amount Tfc when the fluctuation of the knock correction amount Tfc is thus reduced.

  Next, two types of learning values corresponding to the current operating region of the engine 22 are input based on the input rotational speed Ne and volumetric efficiency KL (step S150). Here, the two learning values are updated based on the knock correction amount Tfc when the coolant temperature Tw is equal to or higher than a temperature threshold value Twref (for example, 65 ° C. or 70 ° C.) indicating a state where the engine 22 is warmed up. The normal learning value Tfl1 and the low temperature learning value Tfl2 that is updated based on the knock correction amount Tfc when the coolant temperature Tw is lower than the temperature threshold value Twref are input. In the embodiment, the normal learning value Tfl1 and the low temperature learning value Tfl2 are divided into a plurality of areas (for example, three or four rotation speeds) in which the entire operation area of the engine 22 is divided into the rotation speed Ne and the volumetric efficiency KL. 9 and 16 areas of 3 and 4 volumetric efficiency areas, etc.) are stored in the flash memory 24d, and those corresponding to the current rotational speed Ne and volumetric efficiency KL are respectively stored in the flash memory 24d. It is assumed that the data is read and input, and the value 0 is set as the initial value.

  When the normal learning value Tfl1 and the low temperature learning value Tfl2 are thus input, the cooling water temperature Tw of the engine 22 is compared with the temperature threshold value Twref (step S160). When the cooling water temperature Tw is lower than the temperature threshold value Twref, The sum of the ignition timing Tfb, knock correction amount Tfc, and normal learning value Tfl1 is calculated as the target ignition timing Tf * (step S170), and the ignition coil 138 is driven and controlled so that ignition is performed at the target ignition timing Tf *. (Step S180).

  Subsequently, it is determined whether or not the variation of the knock correction amount Tfc is settled (step S190). When the variation of the knock correction amount Tfc is not settled, the ignition control routine is ended as it is, and the variation of the knock correction amount Tfc is changed. When it is within the range, the normal learning value stored in the flash memory 24d is obtained by adding the knock correction amount Tfc to the normal learning value Tfl1 corresponding to the operation region including the current rotational speed Ne and the volumetric efficiency KL. The normal learning value Tfl1 is updated by replacing Tfl1 (step S200), the knock correction amount Tfc is reset to 0 (step S210), and the ignition control routine is terminated. Here, the determination as to whether or not the variation of the knock correction amount Tfc is within the range of the knock correction amount Tfc within a predetermined time using, for example, a predetermined time and a predetermined amount that are predetermined for an experiment or the like for determination. It can be determined by whether or not the amount (variation width) is less than a predetermined amount.

  FIG. 4 shows an example of how the normal learning value Tfl1 is updated. In the drawing, the ignition timing Tfref shown for reference is whether or not knocking occurs in the engine 22 in a predetermined environmental condition in which knocking is difficult to occur, including the use of the fuel having the highest octane number among the fuels assumed to be used. It is the ignition timing of the boundary. In the figure, as shown on the left side, the knock correction amount Tfc is on the advance side while the normal learning value Tfl1 is learned so as to obtain the target ignition timing Tf * on the advance side with respect to the basic ignition timing Tfb. When the value converges to a positive value, as shown on the right side of the figure, the learning value for normal time Tfl1 is adjusted so that the target ignition timing Tf * on the more advanced side than the basic ignition timing Tfb can be obtained. It is updated as the sum of the normal learning value Tfl1 and the knock correction amount Tfc.

  By such control, when the cooling water temperature Tw is normal or higher than the temperature threshold value Twref, the engine 22 is suppressed while the occurrence of knocking in the engine 22 is suppressed and the normal time learning value Tfl1 is updated so that the ignition timing on the more advanced side can be obtained. The target ignition timing Tf * of 22 can be set and ignition can be performed. As a result, knocking can be suppressed and torque can be output from the engine 22 efficiently.

  When the cooling water temperature Tw is lower than the temperature threshold value Twref in step S160, the sum of the basic ignition timing Tfb, the knock correction amount Tfc, and the learning value for low temperature Tfl2 is calculated as the target ignition timing Tf * (step S220). The ignition coil 138 is driven and controlled so that ignition is performed at the target ignition timing Tf * (step S230).

  Subsequently, whether or not the fluctuation of the knock correction amount Tfc is settled is determined in the same manner as in step S190 (step S240), and learning for low temperature corresponding to the operation region including the current rotational speed Ne and volumetric efficiency KL is determined. It is determined whether the sum of the value Tfl2 and the knock correction amount Tfc is equal to or greater than the normal learning value Tfl1 corresponding to the same operation region (step S250). Here, in the latter determination, when the low-temperature learning value Tfl2 is updated based on the knock correction amount Tfc when the cooling water temperature Tw is lower than the temperature threshold value Twref, the low-temperature learning value Tfl2 becomes the normal-time learning value Tfl1. This is for determining whether or not the value is on the more retarded side (value on the side that retards the ignition timing).

  When the variation in knock correction amount Tfc is within the range and the sum of low temperature learning value Tfl2 and knock correction amount Tfc is equal to or greater than normal learning value Tfl1, the current rotational speed Ne and volumetric efficiency KL are included. The low temperature learning value Tfl2 is updated by replacing the low temperature learning value Tfl2 stored in the flash memory 24d by adding the knock correction amount Tfc to the low temperature learning value Tfl2 corresponding to the operation region (step S260). ), The knock correction amount Tfc is reset to 0 (step S270), and the ignition control routine is terminated. On the other hand, the sum of the low temperature learning value Tfl2 and the knock correction amount Tfc is less than the normal learning value Tfl1 even when the variation of the knock correction amount Tfc does not fall or when the variation of the knock correction amount Tfc falls. When the value is on the retard side, the ignition control routine is terminated as it is. Even when the fluctuation of the knock correction amount Tfc is within the range, when the sum of the low temperature learning value Tfl2 and the knock correction amount Tfc is less than the normal learning value Tfl1 and becomes a retarded value, the next knocking is performed. If the sum of the low temperature learning value Tfl2 and the knock correction amount Tfc is equal to or larger than the normal learning value Tfl1 when the variation in the correction amount Tfc is reduced, the low temperature learning value Tfl2 is updated. Become.

  FIG. 5 shows an example of how the low temperature learning value Tfl2 is updated. In the figure, the ignition timing Tfref shown for reference is the same as that shown in FIG. 4, and the normal learning value Tfl1 is flashed as a learning value in the same operation region as the operation region corresponding to the low temperature learning value Tfl2. It is stored in the memory 24d. As shown on the left side in the figure, the knock correction amount Tfc is retarded while the low temperature learning value Tfl2 is learned so that the advance target ignition timing Tf * is obtained with respect to the basic ignition timing Tfb. When the sum of the low-temperature learning value Tfl2 and the knock correction amount Tfc is less than the normal-time learning value Tfl1 when the value converges to a negative value, the updated low-temperature time The low temperature learning value Tfl2 is maintained without being updated so that the learning value Tfl2 does not become a value that is retarded from the normal learning value Tfl1 (a value that retards the ignition timing). The reason why the low temperature learning value Tfl2 is not retarded from the normal learning value Tfl1 is that the engine 22 is less likely to knock at the low temperature than the normal learning value. When Tfl2 becomes a value on the retard side with respect to the normal time learning value Tfl1, it is based on the fact that the knock correction amount Tfc can be erroneously determined to be a value on the retard side.

  By such control, when the engine 22 is at a low temperature where the coolant temperature Tw is lower than the temperature threshold value Twref, the knock correction amount Tfc is within a range that does not become a value on the retard side (side that retards the ignition timing) from the normal learning value Tfl1. Since the low temperature learning value Tfl2 is updated based on the low temperature learning value Tfl2, learning about the ignition timing of the engine 22 can be performed even at low temperatures, and the target ignition timing Tf * can be set using the low temperature learning value Tfl2. Can output torque efficiently. Further, at low temperatures, for example, the so-called piston noise generated between the piston and the cylinder liner may be erroneously detected as knocking, so that the knock correction amount Tfc may erroneously become a value that delays the ignition timing. Even in this case, since the low temperature learning value Tfl2 is not retarded from the normal learning value Tfl1, it is possible to prevent the ignition timing of the engine 22 from being retarded erroneously at low temperatures. As a result, it is possible to prevent the ignition timing from being retarded erroneously when the engine 22 is at a low temperature and to efficiently output torque from the engine 22.

  According to the ignition control device for an internal combustion engine mounted on the hybrid vehicle 20 of the embodiment described above, when the cooling water temperature Tw of the engine 22 is lower than the predetermined temperature threshold value Twref, the cooling water temperature Tw is the temperature threshold value Twref. The low-temperature learning value at a low temperature based on the knock correction amount Tfc within a range that does not become a value that retards (delays) the ignition timing of the engine 22 from the normal-time normal learning value Tfl1 as described above. Since Tfl2 is updated and the target ignition timing Tf * is set by correcting the reference ignition timing Tfb with the knock correction amount Tfc and the learning value for low temperature Tfl2, the ignition timing of the engine 22 is erroneously delayed at low temperatures. Torque can be output from the engine 22 more efficiently.

  In the ignition control of the engine 22 by the engine ECU 24 of the embodiment, even when the knock correction amount Tfc converges at low temperatures, the sum of the low temperature learning value Tfl2 and the knock correction amount Tfc is less than the normal learning value Tfl1 and is delayed. In the case of the value on the corner side, the low temperature learning value Tfl2 is held without being updated, but the low temperature learning value Tfl2 may be updated with the normal time learning value Tfl1.

  In the ignition control of the engine 22 by the engine ECU 24 of the embodiment, the normal learning value Tfl1 and the low temperature learning value Tfl2 are divided into a plurality of regions in which the entire operation region of the engine 22 is divided into a plurality of numbers by the rotational speed Ne and the volumetric efficiency KL. However, it may be stored and updated for each volume efficiency region obtained by dividing the entire operation region of the engine 22 into a plurality of volumes only by the volume efficiency KL, or the entire operation of the engine 22 may be updated. The area may be stored and updated for each rotation speed area divided into a plurality of areas by only the rotation speed Ne.

  In the ignition control of the engine 22 by the engine ECU 24 according to the embodiment, the normal learning value Tfl1 and the low temperature learning value Tfl2 are replaced with the converged knock correction amount Tfc, thereby learning the normal learning value Tfl1 and the low temperature learning value Tfl2. However, the currently stored normal learning value Tfl1 and the low temperature learning value Tfl2 are weighted to some extent, and these learning values and the converged knock correction amount Tfc are annealed. The normal learning value Tfl1 and the low temperature learning value Tfl2 may be updated by processing.

  In the ignition control of the engine 22 by the engine ECU 24 of the embodiment, the normal learning value Tfl1 and the low temperature learning value Tfl2 are updated on condition that at least the fluctuation of the knock correction amount Tfc is reduced. In addition, for example, a condition in which a certain time elapses after the operation state of the engine 22 ends the transient state, a condition in which the engine 22 is not operated under a light load, or the like may be used.

  In the ignition control of the engine 22 by the engine ECU 24 of the embodiment, the reference ignition timing Tfb is assumed to be an ignition timing within a range in which the engine 22 does not knock even under predetermined environmental conditions in which knocking is likely to occur. As the ignition timing Tfb, for example, the ignition timing Tfref shown in FIGS. 4 and 5 may be used as long as it is based on the operating state of the engine 22.

  In the ignition control of the engine 22 by the engine ECU 24 of the embodiment, when the knock correction amount Tfc converges and the normal learning value Tfl1 and the low temperature learning value Tfl2 are updated, the knock correction amount Tfc is reset to a value of zero. However, in addition to this, the operation region including the current rotational speed Ne of the engine 22 and the volumetric efficiency KL classifies the normal learning value Tfl1 and the low temperature learning value Tfl2 stored in the flash memory 24d. The knock correction amount Tfc may be reset to a value of 0 when shifting from one region to another region among the plurality of operation regions.

  In the embodiment, the present invention is applied to the form of the ignition control device of the internal combustion engine mounted on the hybrid vehicle 20. However, a vehicle including only an engine as a driving power source, a vehicle other than a vehicle, a ship, An ignition control device for an internal combustion engine mounted on a moving body such as an aircraft may be used, or an ignition control device for an internal combustion engine incorporated in a non-moving facility such as a construction facility.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the engine 22 corresponds to an “internal combustion engine”, and gradually increases by a predetermined advance amount ΔTfc1 in accordance with the basic ignition timing Tfc based on the rotational speed Ne and the volumetric efficiency KL and the value of the knock determination flag F. Updated based on the knock correction amount Tfc calculated when the cooling water temperature Tw is equal to or higher than the temperature threshold Twref, and when the knock correction amount Tfc converges at normal time when the cooling water temperature Tw is equal to or higher than the temperature threshold value Twref. The normal time learning value Tfl1 or the cooling water temperature Tw is lower than the temperature threshold value Twref, so that the knock correction amount Tfc converges and does not become a value on the side of retarding the ignition timing from the normal time learning value Tfl1. The target ignition timing Tf * is set as the sum of the learning value Tfl2 for low temperature updated based on the knock correction amount Tfc. The engine ECU 24 that executes processes other than steps S180 and S230 (processes of steps S100 to S170, S190 to S220, and S240 to S270) corresponds to “target ignition timing setting means”, and at the set target ignition timing Tf *. The engine ECU 24 that executes the processing of steps S180 and S230 of the ignition control routine of FIG. 3 that controls the ignition coil 138 so that ignition is performed corresponds to “ignition control means”.

  Here, the “internal combustion engine” is not limited to the engine 22 and may be any type of internal combustion engine that outputs power by ignition of fuel. As the “target ignition timing setting means”, the basic ignition timing Tfb based on the rotational speed Ne and the volumetric efficiency KL, and a predetermined advance amount ΔTfc1 are gradually increased according to the value of the knock determination flag F, or a predetermined delay is set. Knock correction amount Tfc calculated by reducing the angular amount ΔTfc2 and normal time update based on knock correction amount Tfc when knock correction amount Tfc converges at normal time when cooling water temperature Tw is equal to or higher than temperature threshold value Twref When the learning value Tfl1 or the cooling water temperature Tw is lower than the temperature threshold value Twref, the knock correction amount Tfc converges at a low temperature and does not become a value on the side that makes the ignition timing later than the normal learning value Tfl1. It is not limited to the one that sets the target ignition timing Tf * as the sum of the learning value Tfl2 for low temperature that is updated based on the A knock correction amount that is increased or decreased according to the presence or absence of knock so that the ignition timing of the internal combustion engine is advanced within a range in which the knock in the internal combustion engine is suppressed with respect to the reference ignition timing based on the operating state of the fuel engine, and the knock The target ignition timing is set by performing correction based on the learning value updated based on the knock correction amount so that the correction amount is constantly reflected in the ignition timing of the internal combustion engine, and cooling the internal combustion engine At a low temperature where the coolant temperature is lower than a predetermined temperature threshold, the coolant temperature is within a range that does not become the value on the side that retards the ignition timing of the internal combustion engine from the learning value for normal time when the coolant temperature is equal to or higher than the temperature threshold. The learning value for low temperature is updated based on the knock correction amount, and the target ignition timing is set by correcting the reference ignition timing with the knock correction amount and the learning value for low temperature. It may be used as the. The “ignition control means” is not limited to the one that drives and controls the ignition coil 138 so that ignition is performed at the set target ignition timing Tf *, and the internal combustion engine is ignited at the set target ignition timing. As long as it controls the internal combustion engine, it does not matter.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem is the same as that of the embodiment described in the column of means for solving the problem. Therefore, the elements of the invention described in the column of means for solving the problems are not limited. That is, the interpretation of the invention described in the column of means for solving the problems should be made based on the description of the column, and the examples are those of the invention described in the column of means for solving the problems. It is only a specific example.

  As mentioned above, although the form for implementing this invention was demonstrated using the Example, this invention is not limited at all to such an Example, In the range which does not deviate from the summary of this invention, it is with various forms. Of course, it can be implemented.

  The present invention is applicable to the manufacturing industry of ignition control devices for internal combustion engines.

  20 hybrid vehicle, 22 engine, 24 engine electronic control unit (engine ECU), 24a CPU, 24b ROM, 24c RAM, 24d flash memory, 26 crankshaft, 30 planetary gear, 36 drive shaft, 37 differential gear, 38a, 38b drive Wheel, 40 motor electronic control unit (motor ECU), 41, 42 inverter, 43, 44 rotational position detection sensor, 50 battery, 52 battery electronic control unit (battery ECU), 70 hybrid electronic control unit (HV ECU), 80 ignition switch, 81 shift lever, 82 shift position sensor, 83 accelerator pedal, 84 accelerator pedal position sensor, 85 brake pedal, 86 brake pedal Position sensor, 88 vehicle speed sensor, 122 air cleaner, 124 throttle valve, 126 fuel injection valve, 128 intake valve, 130 spark plug, 132 piston, 134 purification device, 134a temperature sensor, 135a air-fuel ratio sensor, 135b oxygen sensor, 136 throttle Motor, 138 Ignition coil, 140 Crank position sensor, 142 Water temperature sensor, 143 Pressure sensor, 144 Cam position sensor, 146 Throttle valve position sensor, 148 Air flow meter, 149 Temperature sensor, 150 Variable valve timing mechanism, 158 Pressure sensor, 159 Knock Sensor, MG1, MG2 motor.

Claims (3)

A knock correction amount that is increased or decreased according to the presence or absence of the knock so that the ignition timing of the internal combustion engine is advanced within a range in which the knock in the internal combustion engine is suppressed with respect to a reference ignition timing based on the operating state of the internal combustion engine And a learning value that is updated based on the knock correction amount so that the knock correction amount is constantly reflected in the ignition timing of the internal combustion engine. And an ignition control device for controlling the internal combustion engine so that the internal combustion engine is ignited at the set target ignition timing,
The target ignition timing setting means is the learning value for normal time when the temperature of the coolant is equal to or higher than the temperature threshold at a low temperature when the temperature of the coolant that cools the internal combustion engine is lower than a predetermined temperature threshold. The learning value for the low temperature is updated based on the knock correction amount within a range that does not become a value on the side of retarding the ignition timing of the internal combustion engine, and the knock correction amount and the reference value for the reference ignition timing are updated. The target ignition timing is set by performing correction with the learning value for low temperature,
An ignition control device for an internal combustion engine. An ignition control device for an internal combustion engine according to claim 1,
When the target ignition timing setting means updates the learning value for the low temperature based on the knock correction amount at the low temperature, the learning value for the low temperature is more than the learning value for the normal time. When it becomes a value on the side of retarding the ignition timing of the engine, it is means for holding the learning value for the low temperature without updating.
An ignition control device for an internal combustion engine. An ignition control device for an internal combustion engine according to claim 1 or 2,
The learning value is a value that is updated based on the knock correction amount for each region obtained by dividing the operating region of the internal combustion engine into at least a plurality of loads by the load of the internal combustion engine.
An ignition control device for an internal combustion engine.

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