WO2002077431A1

WO2002077431A1 - Method and apparatus for controlling idle fuel supply

Info

Publication number: WO2002077431A1
Application number: PCT/JP2001/010823
Authority: WO
Inventors: Yoshiyasu Ito; Yuji Narita
Original assignee: Toyota Jidosha Kabushiki Kaisha; Kabushiki Kaisha Toyota Jidoshokki
Priority date: 2001-03-15
Filing date: 2001-12-11
Publication date: 2002-10-03
Also published as: ES2634837T3; ES2528138T3; JP2002276438A; HUP0302250A3; HU229844B1; EP1369570A1; ES2273295T3; DE60122949D1; CZ20023720A3; DE60122949T2; PL206426B1; EP1369570B1; PL360119A1; EP1555414A1; CZ302163B6; EP1715164B1; EP1715164A1; HUP0302250A2; EP1555414B1; EP1369570A4

Abstract

Idle number of revolution of an internal combustion engine is controlled by calculating an integration correction term based on the difference of actual number of revolution of the internal combustion from a target number of revolution at the time of idling and then correcting fuel supply using that integration correction term. At the time of starting the internal combustion engine and/or immediately after starting the internal combustion engine, anticipated correction corresponding to a friction existing in the initial stage of starting the internal combustion engine is made for fuel supply.

Description

Specification

Method and device for controlling idle fuel supply

The present invention relates to an idle fuel supply control method and apparatus for controlling the idle speed of an internal combustion engine by correcting the fuel supply using an integral correction term. Background art

In a system that executes idle speed control by adjusting the amount of fuel supply, for example, in the idle speed control system of a diesel engine disclosed in Japanese Patent Application Laid-Open No. 11-9347, based on the gapana pattern The basic fuel amount is set based on the rotational speed of the internal combustion engine. Then, for this basic fuel amount, an integral correction term by the deviation of the actual rotational speed from the target rotational speed is calculated, and the integral fuel correction term is used to correct the basic fuel amount. As a result, feedback control of the idle speed is performed. And in order to cope with the external load at the time of change of friction due to the temperature change of the internal combustion engine, the degree of the coolant temperature, the kind of external load such as the air conditioner, power steering etc. and the on · off state And various expected corrections have been made. Stable idle speed control is executed by such expected capture. However, even if the above-described expected correction is performed, immediately after the start of the internal combustion engine, the initial stage of the start of the internal combustion engine can not be caught only by taking into consideration the friction corresponding to the temperature of the internal combustion engine. There is a friction that is specific to Therefore, if the basic fuel amount is corrected by simply calculating the estimated correction term based on the friction predicted according to the temperature of the internal combustion engine, the fuel supply at idle time immediately after the start of the internal combustion engine Insufficient quantity will cause a drop in the rotational speed of the internal combustion engine. Such a reduction in the rotational speed of the internal combustion engine is usually compensated by increasing the fuel supply amount in the above-mentioned integral correction term, and the rotational speed of the internal combustion engine is returned to the target rotational speed. . However, this integral correction term tends to become extremely large when the load such as the half clutch state continues at idle, for example. As described above, if the clutch is disconnected after the integral correction term becomes excessive, the expected correction term due to the clutch engagement and the excessive integration correction term may overlap, and the number of revolutions of the internal combustion engine may rapidly increase. Therefore, the calculation of the integral correction term is usually guarded to prevent the integral correction term from becoming excessive. However, if the control range of the integral correction term by the guard value is narrowed in order to prevent the rapid increase of the rotational speed as described above, the integral correction term can be compensated to compensate for the large friction at the start of the internal combustion engine start. Can not be changed, and a drop in engine speed may cause an engine stall etc., resulting in the inability to perform stable idle rotation. For this reason, the control range of the integral correction term can not be narrowed, and the above-described half clutch etc. may not sufficiently prevent the rapid increase in the number of revolutions of the internal combustion engine. The present invention compensates for friction in the initial stage of startup of the internal combustion engine to prevent a drop in the rotational speed of the internal combustion engine, and idle fuel that can prevent the rapid increase in the rotational speed due to the integral gain term in the idle speed control thereafter. The purpose is to provide a control method and device for supply amount. Disclosure of the invention

Hereinafter, means for achieving the above-mentioned purpose and its effects are described. A control method of an idle fuel supply amount in one embodiment of the present invention calculates an integral correction term based on a deviation of an actual rotational speed of the internal combustion engine from a target rotational speed at the idle time of the internal combustion engine, and the integral correction term By correcting the fuel supply amount using It controls the idle speed of the fuel engine. According to this, at one or both of the start of the internal combustion engine and immediately after the start, an expected correction corresponding to the friction existing in the initial start of the internal combustion engine is performed on the fuel supply amount. As described above, unlike the conventional method, the expected correction corresponding to the friction that is present at the initial stage of starting the internal combustion engine is performed on the fuel supply amount. Therefore, it is possible to cause the actual internal combustion engine rotational speed to converge on the target rotational speed before the value of the deviation of the actual internal combustion engine rotational speed from the target rotational speed is largely accumulated in the integral correction term. . Therefore, since the integral correction term can be suppressed from increasing, the control range of the integral correction term by the guard process can be narrowed. As a result, it is possible to compensate for friction in the initial stage of startup of the internal combustion engine to prevent a drop in the number of revolutions of the internal combustion engine, and to prevent a rapid rise in revolution due to the integral gain term in the subsequent idle revolution control.

The term “initial start” as used herein is a concept encompassing the start and immediately after start. The same is true for the initial startup phase described below. In the preferred idle fuel supply control method, the estimation correction is performed by gradually reducing the estimation correction term set at one or both of start-up and immediately after start-up of the internal combustion engine. In this possibility correction, the present correction is made after compensating for the friction in the initial stage of starting the internal combustion engine by gradually reducing the possibility correction term set at one or both of starting and after starting the internal combustion engine. Shock can be prevented when stopping the engine, and it can be smoothly taken over to the idle speed control after that. In another preferred idle fuel supply control method, a time period for holding the value of the estimated correction term is provided before gradually reducing the estimated correction term. In this way By providing a period for holding the value of the positive term, it is possible to effectively suppress an increase in the integral correction term at the start of the internal combustion engine or immediately after the start without increasing the initial expected correction term extremely. . In still another control method of the idle fuel supply amount, the estimated correction term is gradually reduced according to the elapsed time after the start of the rotation of the internal combustion engine or after the start. As a method of gradually reducing the expected correction term, it may be performed according to the elapsed time after the start of rotation of the internal combustion engine or after the start. By continuing the rotation of the internal combustion engine, the friction at the initial stage of starting the internal combustion engine gradually disappears, so it is possible to appropriately reduce the expected correction term based on the passage of time. As a result, the shock at the time of stopping the estimated correction can be prevented, and the idle speed control can be smoothly taken over. In another preferred idle fuel supply control method, the estimated correction term is gradually reduced according to the integrated rotation speed of the internal combustion engine after the start of rotation of the internal combustion engine or after the start of rotation. Since the friction at the start of the internal combustion engine gradually disappears due to the rotation of the internal combustion engine, the estimated correction term can be appropriately reduced based on the integrated rotation speed by integrating the rotation of the internal combustion engine. As a result, it is possible to prevent a shock when stopping the expected correction, and to smoothly carry over to the idle speed control thereafter. Furthermore, in another idle fuel supply control method, the estimated correction term is gradually reduced according to the temperature rise of the internal combustion engine. As the internal combustion engine continues to operate after the start, the temperature of the internal combustion engine gradually rises. Such a temperature rise pattern is similar to the friction reduction pattern at the start of the internal combustion engine start, and the temperature factor is also involved in the magnitude of the friction at the start of the internal combustion engine start. From this, it is possible to appropriately reduce the expected correction term based on the temperature rise of the internal combustion engine. This prevents a shock when stopping this prospective correction, and The idle speed control can be smoothly taken over. In addition, as the temperature of the internal combustion engine, it is preferable to use a cooling water temperature of the internal combustion engine. In this case, the expected correction term can be appropriately reduced based on the temperature rise of the coolant in the internal combustion engine. This can prevent a shock when stopping the expected correction, and can smoothly carry over to the subsequent idle speed control. As the engine temperature, an engine lubricating oil temperature closely related to the friction may be used instead of the cooling water temperature. In this case as well, the likelihood correction term can be appropriately reduced based on the increase in the lubricant temperature. In restart after engine stall, it is preferable to set the expected correction term to a value at the time of engine stall and start reduction of the expected correction term from the value. In the case of engine stall, the friction at the initial stage of starting, which has been reduced by the rotation of the internal combustion engine just before that, has hardly been recovered. Therefore, in the restart after engine stall, the value of the estimated correction term at the engine stall time is adopted, and the reduction as described above is started from this value. As a result, the expected correction term can be set appropriately, and idle speed control of the internal combustion engine can be made more stable. Preferably, the expected correction term is switched according to the shift position of the transmission. Since the magnitude of friction at the start of the internal combustion engine changes depending on the shift position of the transmission, the magnitude of the expected correction term is switched according to the shift position of the transmission. As a result, the expected correction term can be set appropriately, and idle speed control of the internal combustion engine can be made more stable. The expected correction term can also be switched according to the presence or absence of an external load. Since the size of the friction at the start of the internal combustion engine changes depending on the presence or absence of an external load such as an air conditioner or power steering, the magnitude of the estimated correction term is switched depending on the presence or absence of an external load. As a result, the expected correction term can be set appropriately, and idle speed control of the internal combustion engine can be made more stable. The expected correction term can also be switched according to the type of external load. Since the size of the initial friction of the internal combustion engine changes depending on the type of external load such as air conditioning and power steering, the size of the expected correction term is switched depending on the type of external load. As a result, the expected correction term can be set appropriately, and idle speed control of the internal combustion engine can be made more stable. In an idle fuel supply control method according to another embodiment, an integral correction term is calculated based on a deviation of an actual internal combustion engine speed from a target rotational speed when the internal combustion engine is idle, and an upper limit for the integral correction term is calculated. The guard processing is performed by the guard value and the lower limit guard value, and the idle rotation speed of the internal combustion engine is controlled by correcting the fuel supply amount using the integral correction term after the guard processing. According to this, the control range of the integral correction term between the upper limit guard value and the lower limit guard value is set wider than that in the normal operation at one or both of the start and the start of the internal combustion engine. As described above, the control range of the integral correction term in the guard process is set wider than that in the normal operation particularly at one or both of the start and the start of the internal combustion engine. For this reason, the value of deviation of the actual internal combustion engine speed from the target speed is allowed to be largely accumulated in the integral correction term only at the start of the internal combustion engine and / or immediately after the start. . Therefore, one or both of starting and immediately after starting the internal combustion engine On the other hand, the integral correction term compensates for the friction at the start of the internal combustion engine and prevents the drop in the internal combustion engine speed. Then, at the time of idle speed control thereafter, the control range of the integral correction term is returned to the size at the time of normal operation, so that the integral correction term is prevented from becoming excessive, and the rapid increase in rotation in idle speed control Is prevented. In a preferred embodiment, the guard process gradually narrows the control range of the integral correction term set at one or both after starting of the internal combustion engine to a range of normal operation. In this guard processing, the control range of the integral correction term set at the start of the internal combustion engine and / or immediately after the start is gradually narrowed. By this, after sufficiently compensating the friction in the initial stage of starting of the internal combustion engine with the integral correction term, returning to the control range of the integral correction term in the normal operation and smoothly taking over to the subsequent idle speed control. Can. In addition, before gradually narrowing the control range of the integral correction term, it is preferable to provide a period for maintaining the width of the control range of the integral correction term. Thus, by providing a period for keeping the control range of the integral correction term wide, the integral correction term is not required to be extremely wide at the time of starting the internal combustion engine or immediately after the start of the internal combustion engine. It is possible to allow time for the time to rise sufficiently. By this, it is possible to effectively compensate the friction at the start of the internal combustion engine with the integral correction term. Furthermore, the control range of the integral correction term may be gradually narrowed in accordance with the elapsed time after the start of the internal combustion engine rotation or after the start. As a method of gradually narrowing the control range of the integral correction term, it may be performed according to the elapsed time after the start of the internal combustion engine rotation or after the start. As the internal combustion engine continues to rotate, the friction at the start of the internal combustion engine gradually disappears, so the integral correction term becomes smaller gradually. Because of this time Based on the progress, the control range of the integral correction term can be narrowed appropriately. By this, it is possible to return to the control range of the integral correction term at the time of normal operation and smoothly take over to the idle speed control thereafter. Preferably, the control range of the integral correction term is gradually narrowed in accordance with the integrated engine speed after the start of the internal combustion engine rotation or after the start. As a method of gradually narrowing the control range of the integral correction term, it may be performed according to the integrated rotation speed of the internal combustion engine after the start of the rotation of the internal combustion engine or after the start. Since the rotation of the internal combustion engine gradually disappears at the start of the internal combustion engine, the integral correction term becomes smaller gradually. For this reason, the control range of the integral gain term can be appropriately narrowed by integrating the rotation of the internal combustion engine and based on the integrated rotation speed. As a result, it is possible to return to the control range of the integral correction term at the time of normal operation and smoothly take over to the idle speed control thereafter. It is preferable to gradually narrow the control range of the integral gain term according to the temperature rise of the internal combustion engine. Since the internal combustion engine continues to operate after the start, the temperature of the internal combustion engine gradually rises. Such a temperature rise pattern is similar to the friction reduction pattern at the start of the internal combustion engine start, and the temperature factor is also involved in the magnitude of the friction at the start of the internal combustion engine start. From this, it is possible to appropriately narrow the control range of the integral correction term based on the temperature rise of the internal combustion engine. As a result, it is possible to return to the control range of the integral correction term at the time of normal operation and smoothly take over to the idle speed control thereafter. It is preferable to use the coolant temperature of the internal combustion engine as the temperature of the internal combustion engine. In this case, the control range of the integral correction term can be appropriately narrowed based on the temperature rise of the coolant in the internal combustion engine. As a result, it is possible to return to the control range of the integral gain term during normal operation and smoothly take over to the idle speed control thereafter. When restarting after an engine stall, it is preferable to set the control range of the integral correction term to the range at engine stall and start processing to gradually narrow from the range. In the case of engine stall, the friction at the initial stage of starting, which has been reduced by the rotation of the internal combustion engine just before that, has hardly been recovered. Therefore, in restart after engine stall, the control range of the integral correction term at the engine stall time point is adopted, and from this value, the process of narrowing the control range of the integral correction term as described above is started. As a result, the control range of the integral correction term can be set appropriately, and idle speed control of the internal combustion engine can be made more stable. It is preferable that the control range of the integral acquisition term be switched according to the shift position of the transmission. Since the size of the friction at the start of the internal combustion engine changes according to the shift position of the transmission, the control range of the integral correction term is switched according to the shift position of the transmission. As a result, the control range of the integral correction term can be set appropriately, and idle speed control of the internal combustion engine can be made more stable. The control range of the integral acquisition term is preferably switched according to the presence or absence of an external load. Since the magnitude of friction at the start of the internal combustion engine changes with the presence or absence of an external load such as an air conditioner, the control range of the integral correction term is switched according to the presence or absence of an external load. By this, the control range of the integral positive term can be appropriately set, and idle speed control of the internal combustion engine can be made more stable. The control range of the integral acquisition term is preferably switched according to the type of external load. Since the magnitude of friction at the start of an internal combustion engine changes according to the type of external load such as air conditioner and power steering, the integral The control range of the positive term is switched according to the type of external load. As a result, the control range of the integral correction term can be appropriately set, and idle speed control of the internal combustion engine can be made more stable. It is preferable that the control range of the integral correction term is set based on the learning value of the integral correction term. In this case, it is possible to appropriately guard integral correction terms that tend to fluctuate around the learning value. As a result, the control range of the integral correction term can be appropriately set, and idle speed control of the internal combustion engine can be made more stable. The calculation of the learning value of the integral correction term may be permitted when the control range of the integral correction term returns to the range at the time of normal operation. Under conditions where the control range of the integral correction term is set wider than in normal operation, it is an error to execute the calculation of the learning value of the integral correction term because the integral correction term fluctuates significantly. And is not appropriate. For this reason, when the control range of the integral correction term returns to the normal operation range, calculation of the learning value of the integral correction term is permitted, thereby suppressing the error of the learning value, and the idle rotational speed at one layer is stabilized. Control is possible. According to the control method of the idle fuel supply amount in still another embodiment, the process of performing the expected correction corresponding to the friction existing in the initial stage of the start of the internal combustion engine, and / or at the start and / or immediately after the start of the internal combustion engine. Both the process of setting the control range of the integral correction term wider than at the time of normal operation are executed. As a result, it is possible to more effectively prevent a drop in the internal combustion engine speed by compensating the friction in the initial stage of startup of the internal combustion engine, and the rapid increase of the rotation caused by the integral correction term in the idle speed control thereafter. The effect of preventing While the expected correction term substantially exists, the upper limit guard value and the lower limit guard value It is desirable to set the control range of the integral correction term between to be wider than in normal operation. By correlating the setting of the expected correction term with the expansion of the control range of the integral correction term in this way, compensation of friction in the initial stage of starting the internal combustion engine and prevention of a rapid rise in rotation due to the integral correction term thereafter Can be made more effective. It is desirable that the control range of the integral correction term between the upper limit guard value and the lower limit guard value be gradually narrowed toward the normal operation range in conjunction with the reduction of the expected correction term. By linking the expected correction term and the control range of the integral correction term in this way, it is more effective to compensate for friction at the initial stage of starting the internal combustion engine and to prevent a rapid increase in rotation due to the integral correction term thereafter. It can be The internal combustion engine is preferably a diesel engine. In that case, in the diesel engine, it is possible to compensate for the friction in the initial stage of start-up to prevent a drop in engine speed, and to prevent a rapid rise in engine speed due to the integral correction term in idle engine speed control thereafter. According to one embodiment of the present invention, an idle fuel supply control device is provided. The apparatus comprises first calculating means (calculating means for integral correction term) for calculating an integral correction term based on a deviation of an actual internal combustion engine speed from a target speed when the internal combustion engine is idle; And setting means for setting an expected correction term corresponding to the friction existing at the initial stage of the internal combustion engine at one or both immediately after start-up, the integral correction term calculated by the integral correction term calculation means, and the setting And a second calculation means (fuel supply amount calculation means) for calculating the fuel supply amount by correcting the basic fuel amount with a correction term including the expected capture positive term set by the means. The second calculation means is configured to collect the basic fuel amount by a correction term including the integral correction term calculated by the first calculation means and the expected correction term set by the setting means. The amount of supply is calculated. Among these, the expected correction term is set by the setting means as a correction term corresponding to the friction existing at the initial stage of starting the internal combustion engine at one or both of the time of starting the internal combustion engine and immediately after the start. . For this reason, it is possible to cause the actual internal combustion engine speed to converge on the target rotational speed before the value of the deviation of the actual internal combustion engine speed from the target rotational speed is largely accumulated in the integral correction term. it can. Therefore, since the integral capture term can be suppressed from increasing, the control range of the integral correction term by the guard processing can be narrowed. As a result, it is possible to compensate for friction in the initial stage of startup of the internal combustion engine to prevent a drop in the internal combustion engine speed, and to prevent a rapid rise in rotation due to the integral correction term in the subsequent idle speed control. In a preferred idle fuel supply control system, the setting means gradually reduces the estimated correction term set at one or both of the start of the internal combustion engine and the start of the start of the internal combustion engine. In the setting means, the present correction is made after compensating for the friction in the initial stage of starting the internal combustion engine by gradually reducing the look-up correction term set in one or both of starting the internal combustion engine and immediately after starting. The shock at the time of stopping can be prevented, and it can be smoothly taken over by the idle speed control thereafter. In another suitable controller for controlling the amount of idle fuel, the setting means sets a period for holding the value of the estimated correction term before gradually reducing the estimated correction term. In this case, it is possible to effectively suppress the increase of the integral correction term at the start of the internal combustion engine or immediately after the start without increasing the initial expected correction term extremely. Furthermore, in the setting means, the process of gradually reducing the estimated correction term may be performed according to the elapsed time after the start of the rotation of the internal combustion engine or after the start. By continuing the rotation of the internal combustion engine, the friction at the start of the internal combustion engine gradually disappears- Based on the passage of time, the setting means can appropriately reduce the expected correction term. As a result, it is possible to prevent a shock when the setting means reduces the expected correction term, and to smoothly carry over to the subsequent idle speed control. The setting means may gradually reduce the expected correction term in accordance with the integrated engine rotation speed after starting or after starting the internal combustion engine. In this case, since the friction in the initial stage of starting the internal combustion engine gradually disappears due to the rotation of the internal combustion engine, the setting means appropriately reduces the expected correction term based on the integrated rotation speed after calculating the rotation of the internal combustion engine. be able to. As a result, it is possible to prevent a shock when the setting means reduces the expected correction term and to smoothly carry over to the subsequent idle speed control. In a preferred idle fuel supply control system, the setting means gradually reduces the expected correction term in response to the temperature rise of the internal combustion engine. As the internal combustion engine continues to operate after the start, the temperature of the internal combustion engine gradually rises. Such a temperature rise pattern is similar to the friction reduction pattern at the start of the internal combustion engine start, and the temperature factor is also involved in the magnitude of the friction at the start of the internal combustion engine start. From this, based on the temperature rise of the internal combustion engine, the setting means can appropriately reduce the expected correction term. As a result, the shock when the setting means reduces the expected correction term can be prevented, and the subsequent idle speed control can be smoothly taken over. The setting means may use a coolant temperature of the internal combustion engine as the temperature of the internal combustion engine. Therefore, the setting means can appropriately reduce the expected positive value based on the temperature rise of the coolant in the internal combustion engine. As a result, it is possible to prevent the shock when the setting means reduces the expected correction term, and to smoothly carry over to the subsequent idle speed control. In a preferable idle fuel supply control device, the setting means sets the estimated correction term to a value at the time of engine stall and restarts the reduction from the value at restart after engine stall. In the case of engine stall, the friction at the initial stage of starting, which has been reduced by the rotation of the internal combustion engine until just before, has hardly been recovered. For this reason, in the restart after engine stall, the setting means adopts the value of the expected correction term at the time of engine installation, and starts the above-mentioned reduction from this value. As a result, the setting means can appropriately set the expected correction term, and the idle speed control of the internal combustion engine can be made more stable. Since the magnitude of friction at the start of the internal combustion engine changes depending on the shift position of the transmission, the setting means may switch the magnitude of the expected correction term according to the shift position of the transmission. By this, the setting means can appropriately set the expected correction term, and idle speed control of the internal combustion engine can be made more stable. Since the magnitude of friction at the start of the internal combustion engine changes depending on the presence or absence of an external load such as an air conditioner or power steering, the setting means switches the magnitude of the above-mentioned expected correction term depending on the presence or absence of an external load. You may By this, the setting means can appropriately set the estimated positive term, and the idle speed control of the internal combustion engine can be made more stable. Since the size of the friction at the start of the internal combustion engine changes according to the type of external load such as air conditioner and power steering, the setting means switches the size of the expected correction term according to the type of external load. It is also good. By this, the setting means can set the expected correction term appropriately, and the idle speed control of the internal combustion engine can be made more stable. The idle fuel supply control device of the preferred embodiment calculates an integral correction term based on the deviation of the actual internal combustion engine speed from the target rotational speed at the time of an internal combustion engine idle, and the integral correction term is calculated with respect to the integral correction term. The guard processing is performed by the upper limit guard value and the lower limit guard value, and at one or both of the start of the internal combustion engine and immediately after the start, the control range of the integral correction term between the upper limit guard value and the lower limit guard value is A first calculation means which is set wider than in normal operation, and a correction term including the integral correction term calculated by the first calculation means, for calculating the fuel supply amount by correcting the basic fuel amount; And 2 calculating means. As described above, the first calculation means sets the control range of the integral correction term in the guard processing to be wider than that in the normal operation at one or both of the startup and immediately after startup of the internal combustion engine. Therefore, the value of deviation of the actual engine speed from the target engine speed may be accumulated largely in the integral correction term only at the start of the internal combustion engine and / or immediately after the start. . Therefore, for one or both of starting and immediately after starting the internal combustion engine, the integral correction term calculated from the first calculation means compensates for the friction in the initial stage of starting the internal combustion engine and prevents the drop of the internal combustion engine speed. It is done. Then, at the time of idle speed control after that, the first calculation means returns the control range of the integral correction term to the size at the time of normal operation, and therefore prevents the integral correction term from becoming excessive. It is possible to prevent a sudden rise in rotation in control. In the guard process, the first calculation means may gradually narrow the control range of the integral correction term set at one or both after start-up and immediately after start-up of the internal combustion engine to make it a range during normal operation. As a result, the first calculation means fully compensates for the friction in the initial stage of startup of the internal combustion engine with the integral correction term, and then returns to the control range of the integral correction term in normal operation to smoothly control the idle speed thereafter. Be handed over to Can. The first calculation means may provide a period for holding the width of the control range of the integral correction term before gradually narrowing the control range of the integral correction term. At the start of the internal combustion engine or immediately after the start, it is possible to provide a time margin until the integral correction term sufficiently rises without extremely widening the control range of the integral correction term. This makes it possible to effectively compensate for the friction at the initial stage of the internal combustion engine with the integral acquisition term. The first calculation means may perform the process of gradually narrowing the control range of the integral correction term according to the elapsed time after the start of rotation of the internal combustion engine or after the start. As the internal combustion engine continues to rotate, the friction at the start of the internal combustion engine gradually disappears, so the integral capture term becomes smaller gradually. Therefore, based on the passage of time, the first calculation means can appropriately narrow the control range of the integral correction term. By this, the first calculation means can return to the control range of the integral correction term at the time of normal operation, and can smoothly take over to the idle speed control thereafter. The first calculation means may perform the process of gradually narrowing the control range of the integral correction term according to the integrated engine rotational speed after starting or after starting the internal combustion engine. As the internal combustion engine's rotation causes the friction at the start of the internal combustion engine to disappear gradually, the integral correction term becomes smaller gradually. For this reason, the first calculation means can appropriately narrow the control range of the integral correction term based on the integrated number of revolutions of the internal combustion engine. As a result, the first calculation means can return to the control range of the integral correction term at the time of normal operation and smoothly take over to the idle speed control thereafter. The first calculation means may gradually narrow the control range of the integral correction term according to the temperature rise of the internal combustion engine. As the internal combustion engine continues to operate after the start, the temperature of the internal combustion engine gradually rises. Such a temperature rise pattern is Similar to the friction reduction pattern at the beginning of start-up, the temperature factor is also involved in the magnitude of the friction at the start-up of the internal combustion engine. From this, based on the temperature rise of the internal combustion engine, the first calculation means can appropriately narrow the control range of the integral correction term. As a result, the first calculation means can return to the control range of the integral correction term at the time of normal operation and smoothly take over to the idle speed control thereafter. The first calculation means can use the coolant temperature of the internal combustion engine as the temperature of the internal combustion engine. Therefore, based on the increase in the coolant temperature of the internal combustion engine, the first calculation means can appropriately narrow the control range of the integral correction term. As a result, the first calculation means can return to the control range of the integral gain term during normal operation and smoothly take over to the idle speed control thereafter. In the restart after engine stall, the first calculation means may set the control range of the integral correction term to a range at the time of engine stall and start processing to gradually narrow from the range. In the case of engine stall, the friction at the initial stage of starting, which has been reduced by the rotation of the internal combustion engine until just before, has hardly been recovered. Therefore, in the restart after engine stall, the first calculation means adopts the control range of the integral positive term at the engine stall time and narrows the control range of the integral positive term from this value as described above. Start the process. As a result, the first calculation means can appropriately set the control range of the integral correction term, and can make the idle speed control of the internal combustion engine more stable. The first calculation means may switch the control range of the integral correction term according to the shift position of the transmission. Since the size of the friction at the start of the internal combustion engine changes depending on the shift position of the transmission, the first calculation means switches the control range of the integral correction term according to the shift position of the transmission. By this, the first calculation means can appropriately set the control range of the integral correction term, Idle speed control of the internal combustion engine can be made more stable. The first calculation means may switch the control range of the integral correction term according to the presence or absence of an external load. Since the magnitude of friction at the initial stage of starting the internal combustion engine changes depending on the presence or absence of an external load such as an air conditioner or power steering, the first calculation means determines the control range of the integral correction term as the presence or absence of an external load. Switch it on later. By this, the first calculation means can appropriately set the control range of the integral correction term, and the idle speed control of the internal combustion engine can be made more stable. The first calculation means may switch the control range of the integral correction term according to the type of the external load. Since the size of the friction at the initial stage of startup of the internal combustion engine changes depending on the type of external load such as air conditioner and power steering, the first calculation means sets the control range of the integral correction term to the type of external load. Switch it on later. As a result, the first calculation means can appropriately set the control range of the integral correction term, and the idle speed control of the internal combustion engine can be made more stable. The first calculation means may set a control range of the integral correction term on the basis of a learning value of the integral correction term. In this case, it is possible to appropriately guard integral correction terms that tend to fluctuate around the learning value. By this, the first calculation means can appropriately set the control range of the integral correction term, and the idle speed control of the internal combustion engine can be made more stable. In the preferred idle fuel supply control system, the integral correction term learning for calculating the learning value of the integral correction term when the control range of the integral correction term in the first calculation means is returned to the normal operation range. Prepare the means: In a situation where the control range of the integral correction term is set wider than in normal operation, the integral correction term largely fluctuates, so the integral correction term learning means executes the calculation of the learning value of the integral correction term. Are prone to errors and not appropriate. Therefore, when the control range of the integral correction term in the first calculation means returns to the range at the time of normal operation, the integral correction term learning means performs calculation of the learning value of the integral correction term. As a result, the error in the learning value is suppressed, and more stable idle speed control is possible. In an idle fuel supply control device according to another embodiment, setting means for setting an expected correction term corresponding to the friction existing at the initial stage of starting the internal combustion engine at one or both of the start of the internal combustion engine and immediately after the start; The integral correction term is calculated based on the deviation of the actual internal combustion engine speed from the target speed during idling of the internal combustion engine, and the integral correction term is subjected to guard processing by the upper limit guard value and the lower limit guard value. At one or both of starting and immediately after starting of the internal combustion engine, the control range of the integral correction term between the upper limit guard value and the lower limit guard value is set wider than that in the normal operation. And calculating means. As a result, it is possible to compensate for friction in the initial stage of starting the internal combustion engine and to more effectively prevent a drop in the internal combustion engine speed, and a rapid increase in rotation due to the integral correction term in the subsequent idle speed control. The effect of being able to prevent The first calculation means is configured to set the control range of the integral correction term between the upper limit guard value and the lower limit guard value wider than that during normal operation while the expected correction term substantially exists. May be In this case, the first calculation means corresponds the expansion of the control range of the integral correction term to the setting state of the expected correction term. As a result, it is possible to more effectively compensate for friction in the initial stage of starting the internal combustion engine and to prevent the rapid rise in rotation due to the integral correction term thereafter. The first calculation means, in conjunction with the reduction of the expected correction term by the setting means, sets the control range of the integral correction term between the upper limit guard value and the lower limit guard value to a range during normal operation. It is preferable to make it narrower gradually. In this case, the first calculation means interlocks the expected correction term and the control range of the integral correction term. As a result, it is possible to more effectively compensate for friction in the initial stage of starting the internal combustion engine and to prevent the rapid rise of the rotation due to the integral correction term thereafter. The idle fuel supply control device is preferably applied to a diesel engine. In this case, in the diesel engine, it is possible to compensate for friction in the initial stage of start-up to prevent a drop in engine speed and to prevent a rapid rise in engine speed due to an integral correction term in idle engine speed control thereafter. Brief description of the drawings

FIG. 1 is a schematic configuration view showing a pressure accumulation type diesel engine as a first embodiment and a control system thereof.

Fig. 2 is a flow chart of the fuel injection amount control process executed by the ECU according to the first embodiment.

FIG. 3 is a map configuration diagram for calculating a governor injection amount t Q G O V 1 and t Q G O V 2 from the engine rotational speed N E and the opening degree A C C P used in the control processing of the fuel injection amount.

FIG. 4 is a flowchart of I S C control processing executed by the E C U of the first embodiment. Figure 5 is a flow chart of the calculation process of the integral integral positive term learning value Q I XM as well.

Fig. 6 is a flowchart of the guard processing of the integral correction term Q I I as well.

Fig. 7 is a flowchart of the calculation processing of the I SC expected correction term.

Fig. 8 is a map configuration diagram used in the calculation process of QIPAS and in the calculation process of ISC expected capture positive term. Fig. 9 is a map configuration diagram used in the calculation processing of the ISC expected correction term.

Figure 10 is a flow chart of the calculation process of the start-up initial estimated correction term Q I P A S performed by the ECU according to the first embodiment.

Figure 11 shows the same flow chart of the timer counter Ts counting process after startup.

FIG. 12 is a timing chart showing an example of processing in the first embodiment.

FIG. 13 is a timing chart showing an example of processing in the first embodiment.

Fig. 14 is a flowchart _c of the guard value setting process executed by the ECU according to the second embodiment. Fig. 15 is a flowchart of the process of calculation of the integral correction term learning value QI XM.

FIG. 16 is a timing chart showing an example of processing in Embodiment 2.

FIG. 17 is a timing chart showing an example of processing in Embodiment 2. BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1

FIG. 1 is a schematic configuration view showing a pressure accumulation type diesel engine (common rail type diesel engine) 1 as a first embodiment and its control system. This diesel

Reference numeral 2 denotes an internal combustion engine mounted on a vehicle for driving the vehicle. The diesel engine 1 is provided with a plurality of cylinders (in the present embodiment, four cylinders, but only one cylinder is shown), forests # 1, # 2, # 3, # 4, and each cylinder # 1 The injectors 2 are respectively disposed in the combustion chambers # 4 to # 4. The fuel injection timing and fuel injection amount from the injector 2 to the cylinders # 1 to # 4 of the diesel engine 1 are controlled by turning on and off the solenoid valve 3 for injection control. The injector 2 is connected to the common rail 4 as a common pressure accumulation pipe for each cylinder, and while the solenoid valve 3 for injection control is open, the fuel in the common rail 4 is connected to each cylinder # 1 to # 4. Is injected into the combustion chamber of the A relatively high pressure corresponding to the fuel injection pressure is accumulated in the common rail 4. In order to realize this pressure accumulation, the common rail 4 is connected to the discharge port 6 a of the supply pump 6 via the supply pipe 5. Also, a check valve 7 is provided in the middle of the supply pipe 5. The presence of the check valve 7 permits the supply of fuel from the supply pump 6 to the common rail 4, and regulates the backflow of fuel from the common rail 4 to the supply pump 6. The supply pump 6 is connected to the fuel tank 8 via the suction port 6b, and a filter 9 is provided in the middle thereof. The supply pump 6 sucks fuel from the fuel tank 8 through the filter 9. At the same time, the supply pump 6 reciprocates the plunger by a cam (not shown) synchronized with the rotation of the diesel engine 1 to raise the fuel pressure to the required pressure and supply high pressure fuel to the common rail 4. ing. Further, a pressure control valve 10 is provided near the discharge port 6 a of the supply pump 6. The pressure control valve 10 is for controlling the fuel pressure (ie, injection pressure) discharged from the discharge port 6 a toward the common rail 4. By opening the pressure control valve 10, the surplus fuel not discharged from the discharge port 6a is returned to the fuel tank 8 through the return pipe 11 from the return port 6c provided on the supply pump 6. It is supposed to be An intake passage 13 and an exhaust passage 14 are connected to the combustion chamber of the diesel engine 1 respectively. In the combustion chamber of the diesel engine 1, a glow plug 1 8 is disposed. The glow plug 18 is red-heated by applying an electric current to the glow relay 1 8 a immediately before the start of the diesel engine 1, and a part of the fuel spray is blown to this to promote ignition and combustion. Start-up assistance device. The diesel engine 1 is provided with the following various sensors and the like, which detect the operating state of the diesel engine 1 in the first embodiment. That is, an acceleration sensor 20 for detecting an accelerator opening ACCP is provided in the vicinity of the accelerator pedal 19. Further, an intake air amount sensor 22 is provided in the intake passage 13 to detect an intake air amount GN flowing through the intake passage 13. The cylinder block of the diesel engine 1 is provided with a water temperature sensor 24 for detecting the temperature (cooling water temperature T HW) of the engine cooling water. Further, a fuel temperature sensor 26 for detecting the fuel temperature is provided in the above-mentioned return pipe 11. The common rail 4 is provided with a fuel pressure sensor 27 for detecting the pressure of the fuel in the common rail 4 (injection pressure PC). In the first embodiment, an NE sensor (engine speed sensor) 28 is provided in the vicinity of a pulser (not shown) provided on a crankshaft (not shown) of the diesel engine 1. Further, the rotation of the crankshaft is transmitted to a camshaft (not shown) for opening and closing the intake valve 31 and the exhaust valve 32 via a timing belt or the like. This camshaft is set to rotate at a rotational speed of 1 Z 2 rotation of the crankshaft. A G sensor (acceleration sensor) 29 is provided in the vicinity of a pulsar (not shown) provided on the camshaft. In the first embodiment, the engine speed NE, the crank angle CA, and the top dead center (TDC) of each of the cylinders # 1 to # 4 are calculated from the pulse signals output from these two sensors 28 and 29. Ru. Further, on the output shaft of the transmission (not shown), a vehicle speed sensor 30 is provided for detecting the vehicle speed S PD from the number of revolutions of the output shaft. Furthermore, an air conditioner driven to rotate by the output of the diesel engine 1 Air conditioner for turning on / off 34 4, diesel engine 1 Power steering that indicates whether the power steering that is driven using the hydraulic pressure from the hydraulic pump rotationally driven by the output of the function is functioning. Switch 36, Alternator power generation control circuit 38 provided in the alternator to adjust the power generation of the alternator with the control duty signal 38, Neutral switch indicating that the range position of the automatic transmission provided in the diesel engine 1 is neutral 4 0, idle-up switch 42, which is turned on or off when making a manual change from normal idle state to idle-up state or a manual change from idle-up state to normal idle state. Starter to detect the operating condition of the starter Chi 4 3 and the like. In the first embodiment, an electronic control unit (ECU) 44 for controlling various controls of the diesel engine 1 is provided. The ECU 44 controls the diesel engine 1 such as fuel injection amount control. Processing is performed. The ECU 4 4 includes a central processing control unit (CPU), a read only memory (ROM) storing various programs or maps described later in advance, a random access memory (RAM) temporarily storing the calculation result of the CPU, It has a backup RAM that backs up calculation results and prestored data, and a timer counter, and also has an input interface and an output interface. These members are connected by a bus. The aforementioned accelerator sensor 20, intake air amount sensor 22, water temperature sensor 24, fuel temperature sensor 26, fuel pressure sensor 27, alternator power control circuit 38 are respectively buffer, multiplexer, A / D converter It is connected to the input interface via (not shown). The NE sensor 28, the G sensor 29, and the vehicle speed sensor 30 are connected to the input interface via a waveform shaping circuit (not shown). In addition, air conditioner switch 3 4, power steering The switch 36, the neutral switch 40, the idle switch 42 and the switch 43 are directly connected to the input interface. The CPU reads the signals of the above sensors via the input interface. The solenoid valve 3, the pressure control valve 10 and the glow relay 1 8 a are connected to the output interface via a drive circuit (not shown). The CPU performs control calculation based on the input value read through the input interface, and preferably controls the solenoid valve 3, the pressure control valve 10 and the glow relay 1 8 a through the output interface. Next, a fuel injection amount control process executed by the ECU 44 in the first embodiment will be described based on the flowchart of FIG. This process is, for each injection, here a four-cylinder diesel engine 1, so the crank angle 180. Interrupts are executed every time. The individual processing contents and the steps in the flowchart corresponding to the processing contents are indicated by "S". When control processing of the fuel injection amount is started, first, the operating condition of the diesel engine 1, that is, here, the engine speed NE obtained from the signal of the NE sensor 28, and the accelerator opening degree AC CP obtained from the signal of the accelerator sensor 20. The integral correction term QII, ISC expected load correction term QI PB, and ISC expected rotation speed correction term QI PNT calculated by ISC (idle speed control) processing described later are provided in the RAM of E CU 44. Load into the working area (S1 10). Next, the idle governor injection amount t QGOV 1 and the traveling governor injection amount t QGOV 2 are calculated from the map shown in FIG. 3 in which the relationship between the engine rotational speed NE and the accelerator opening AC CP is set (S 120) . As can be seen from FIG. 3, the idle governor injection amount t QGOV 1 is in the low speed range of the engine, that is, the car is mainly idle. This is the injection amount when it is in the state, and is shown by the broken line in FIG. Further, the traveling governor injection amount t QGOV2 is the injection amount when the engine is in a high rotation range, that is, when the vehicle is mainly in a traveling state, and is shown by a solid line in FIG. Next, the value obtained by adding the idle governor injection amount t QGOV 1 to the integral correction amount Q II, ISC expected load correction term QI PB and I SC expected rotational speed correction term QI PNT, and the traveling governor injection amount t QGOV 2 The value obtained by adding the SC expected load correction term QIPB is compared, and the larger value is calculated as the governor injection amount QGOV (S130). Therefore, as can be seen from FIG. 3, in the low speed range of the engine 1, that is, when the engine 1 is mainly in idle rotation state, the above-mentioned idle governor injection amount t QGOV 1 integrated correction amount QII, ISC expected load correction A value obtained by adding the terms QIPB and ISC expected rotational speed correction term QIP NT tends to be selected as the governor injection amount QGOV. On the other hand, when the engine 1 is in the high speed range, that is, when the vehicle is mainly traveling, a value obtained by adding the ISC expected load correction term QIPB to the traveling governor injection amount t QGOV 2 is selected as the governor injection amount QGOV. Tend to be Next, the maximum injection amount Q FULL is calculated (S 140). Here, the maximum injection amount QFU LL is the upper limit value of the amount of fuel to be supplied to the combustion chamber, and is the limit value for suppressing the rapid increase of the smoke discharged from the combustion chamber and the excessive torque. Next, the smaller of the maximum injection amount QFUL L and the governor injection amount QGOV is calculated as the final injection amount QF IN (S 150). Then, the injection amount command value (time converted value) TSP corresponding to the final injection amount QF IN is calculated (S1 60), and this injection amount command value TSP is output (S1 70). End the process. The solenoid valve 3 of the injector 2 is driven and controlled by the output of the injection amount command value TSP, and fuel injection is performed. The flowchart in Figure 4 shows ISC (idle speed control) processing. This process is interrupted at each injection when idle.

When this process is started, first, the opening degree ACCP obtained from the signal of the accelerator sensor 20, the cooling water temperature THW obtained from the signal of the water temperature sensor 24, the engine rotational speed NE obtained from the signal of the NE sensor 28, Vehicle speed SPD obtained from the signal of the vehicle speed sensor 30, on / off state obtained from the air conditioner detector 34, on / off state obtained from the power steering switch 36, and alternator power control circuit 38 units The alternator control utility DU etc. to be stored are read into the work area provided in the RAM of the ECU 44 (S 210). Then, it is judged whether or not it is currently in an idle state (S 220). For example, if all the conditions that the accelerator opening AC CP is less than the predetermined opening close to full closing and the vehicle speed S PD = 0 k x n / h are satisfied, it is determined that the vehicle is in the idle state. . If it is not in the idle state ("NO" in S220), the process is terminated as it is. If it is idle ("YES" in S 220), then the air conditioner's on / off status, power steering on / off status, electrical load appearing on the alternator control duty DU, and coolant temperature THW The appropriate idle target rotation speed NETRG is set corresponding to the degree of (S 230). This setting is made based on map data stored in the ROM of the ECU 44. Specifically, the idle target rotation speed NE TRG is set to be high at the air conditioner's ON state, power steering ON state, high electric load side, and low coolant temperature THW side. Next, deviation of the actual engine speed NE relative to the idle target speed NET RG The difference NEDL is calculated as shown in the following equation 1 (S 240).

NED L NETRG-NE ... [Equation 1] Then, in accordance with the deviation NED L calculated in this manner, the integral amount AQ I I is calculated based on the map stored in the ROM of the ECU 44 (S250). Specifically, the integral quantity AQ I I is set to a positive value when the deviation NEDL is on the positive side, and the integral quantity ΔQ I I is set to a negative value when the deviation NED L is on the negative side. Next, the integral correction AQ II calculated in step S 250 is added to the integral correction term QII (i 1 1) of the fuel injection amount calculated in the previous control cycle, and the integration correction this time Calculated as the term QII (i) (S 260). Next, the integral correction term learning value Q I XM is calculated (S 270). The calculation process of the integral correction term learning value Q I XM is as shown in the flowchart of FIG.

That is, first, it is determined whether an increase update condition of the integral correction term learning value Q I XM is satisfied (S 271). The incremental update condition is satisfied when the conditions of the following Equation 2 and Equation 3 are satisfied.

NE NET NETRG · · · [Equation 2]

Q I I (i)> Q I XM (i-1) ... [Equation 3]

Here, QI XM (i-1) is obtained at the previous control cycle for each setting such as presence or absence of external load such as an air conditioner, or idle setting such as on / off of the idle up switch 42. Integral correction term learning value QI XM. If the previous control cycle and the current control cycle are different due to switching of the external load, etc., the equation 3 does not hold. If Equation 2 and Equation 3 both hold (S271 “YES”), the integral correction term learning value QI XM (i) in this control period is calculated according to the following Equation 4 S 272) ₀

QI XM (i) <-QI XM (i-1) + IQII MD L ... [Equation 4] where the incrementally updated value IQI IMDL gradually increases the integral correction term learning value QI XM (i 1 1) of the previous control cycle. Represents a constant for If either or both of Equations 2 and 3 do not hold (“N」 ”in S 271), then it is determined whether the decrease update condition for the integral correction term learning value QI XM is satisfied. (S273). The decrease update condition is satisfied when the conditions of the following equations 5 and 6 are satisfied.

NE NET NETRG · · · [Equation 5]

Q I I (i) <Q I XM (i-1) ... [Equation 6]

Note that, in the idle state where the previous control cycle and the current control cycle are different due to switching of the external load or the like, it is assumed that the formula 6 does not hold. If Equation 5 and Equation 6 are both satisfied (“YE S” in S 273), the integral correction term learning value QI XM (i) in this control period is calculated according to the following Equation 7 S 274) ₀

QI XM (i) QI XM (i-1)-DQ I IMDL ... [Equation 7] Here, the decrease update value DQ I IMDL gradually decreases the integral correction term learning value QIXM (i-1) of the previous control cycle. Represents a constant for In the present embodiment, the decrease update value DQ I IMDL is set to a value equal to the increase update value IQII MD L, but the decrease update value DQ I IMDL may be different from the increase update value IQ II MD L . If either or both of the above equations 5 and 6 are not established (“N 0” in S 273), the integral correction term learning value QI XM (i) in this control period is the previous control period The integral captive positive term learning value QI XM (i -1) at is set as it is (S 275). Note that the previous control cycle and the current control cycle are switched by switching the external load, etc. In the case of an idle state different from this, the integral acquisition term learning value QI XM (i) in this control cycle is set to the newest integral correction term learning value QI XM in the same idle state as this time. .

When integration correction term learning value QI XM (i) in this control cycle is calculated in S 272, S 274 and S 275, calculation processing of integral correction term learning value QI XM (FIG. 5) is ended. . Then, the upper limit guard value Q I I GMX and the lower limit guard value Q I I GMN are calculated by the I SC processing (FIG. 4) (S 280). These guard values Q I GMX and Q I I GMN are provided for each air conditioner, etc., with or without external load, or for each idle setting state such as idle-up switch 42 on / off. Therefore, in step S280, an appropriate guard value Q I I GMX, Q I I GMN is set according to such an idle setting state. Note that these guard values Q I I GMX and Q I I GMN are set as the widths to the upper and lower limits with respect to the integral correction term learning value Q I XM (i). Next, guard processing is performed on these integral correction terms Q I I (i) by these guard values Q I I GMX and Q I I GMN (S 290).

The guard processing of this integral correction term QII is shown in the flowchart of FIG. First, it is judged whether or not the integration correction term Q I I (i) of this time satisfies the relation of the following expression 8 (S 291).

QII (i)> QI XM (i) + QII GMX ... [Equation 8] This equation 8 indicates that the integral correction term QII (i) calculated as described above exceeds the upper limit in the control range of the integral correction term Is shown. If the above equation 8 is satisfied

The upper limit value of the control range of the integral correction 3⁄4 is set to the integral correction term QII (i) of this time (S 292), as shown in the following equation 9 (“YES” in S 291). QII (i) QI XM (i) + QII GMX ... [Equation 9] In this way, this integral correction term QII guard processing (Fig. 6) is exited. If the equation 8 is not satisfied (“NO” in S 29 1), then it is determined whether the current integral correction term QII (i) satisfies the relationship of the following equation 10: (S 293).

QII (i) QI XM (i) 1 QII GMN ... [Equation 10] In this equation 10, the integral correction term QII (i) calculated as described above is below the lower limit of the control range of the integral correction term It is shown that. If the equation 10 is satisfied (“YES” in S 29 3), the lower limit value of the control range of the integral correction term is set to the integral correction term QII (i) as shown in the following equation 1 1 (S 294).

Q I I (i) ^ Q I X M (i) One Q I I GMN ... [Equation 1 1] Thus, this integral correction term Q I I guard processing (Fig. 6) is left. Also, when the above equation 10 is not satisfied (“NO” in S 293), the integral correction term QII (i) is maintained and the guard processing of this integral correction term QII (FIG. 6) is performed. Get out. Then, in the I SC process (FIG. 4), the calculation process of the I SC expected capture positive term is executed (S 300). Details of the calculation process of this I SC expected correction term are shown in the flowchart of FIG.

In the calculation process of the I SC expected correction term (FIG. 7), first, based on the idle target rotational speed NETRG calculated in step S 230 described above, the rotational speed correction term QI is obtained from a map obtained in advance by experiment. Calculate PNT (S410). This speed correction term QI PNT compensates for the lack of fuel or the fuel excess caused by the change of idle target speed NETRG due to the nature of the governor pattern (Figure 3) described above. It is a correction term to complete. Next, based on the cooling water temperature THW, a cold correction term QIPBCL is calculated from the map shown in FIG. 8 (B) (S 40). The cold correction term QI PB CL is a correction term for reflecting the degree of the influence on the friction caused by the low temperature of the engine 1 in the fuel injection amount. Next, from the map shown in FIG. 8C, the electric load correction term QI PBDF is calculated based on the alternator control duty DU (S 440). The electrical load correction term QI PBDF is a correction term for reflecting the amount of power consumption used in vehicles such as glow plugs 18 and head lamps in the fuel injection quantity. This utilizes the fact that the amount of electricity used is reflected in the alternator control duty DU, which regulates the output of the alternator. Next, it is determined whether the air conditioner is on (S450). If the energy conditioner is in the on state ("YES" in S450), the air conditioner correction term QI PBAC is calculated from the map shown in Fig. 9 (A) based on the actual engine speed NE. To do (S 460). The air conditioner correction term QI PBAC is a correction term for reflecting the load of the air conditioner on the fuel injection amount, and is adjusted in accordance with the rotational speed NE of the engine 1.

If the air conditioner is off ("NO" in S450), "0" is set in the air conditioner correction item QI PBAC (S470). Next, it is determined whether the power steering is on (S480). If power steering is on (“YE S_” at S 4 80), the power steering acquisition term QI PB PS is calculated from the map shown in FIG. 9 (B) based on the actual engine speed NE. Calculate (S 490) This power steering correction term QI PB PS This correction term is for reflecting the load caused by power steering in the fuel injection amount, and is adjusted according to the rotational speed NE of the engine 1.

If the power steering is off ("NO" in S480), "0" is set to the power steering correction term QIPBPS (S500). Among the correction terms calculated as described above, the cold correction term QI PBCL, the electric load correction term QIP BDF, the air conditioner correction term QIPB AC, the power steering correction term QIPBPS, and the correction of the initial start forecast described later The term QIPAS is summed to calculate the load correction term QI PB (S510). In this way, ISC estimate correction term calculation processing (Fig. 7) is exited, and ISC control processing (Fig. 4) is processed once and for all. By calculating the integral correction term QII, the rotational speed acquisition positive term QIP NT, and the load correction term QI PB in this manner, generation of load is indicated by step S 1 of the fuel injection amount control process (FIG. 2) described above. This is reflected in the calculation of governor injection amount QGOV at 30. As a result, the governor injection amount QGOV is determined such that the engine rotational speed NE becomes the idle target rotational speed NET RG according to the load. The process to calculate the QI PAS is shown in the flowchart of Fig. 10. This process is repeatedly executed by interruption every fixed short time, not limited to idle time. First, it is determined from the output of the neutral switch 40 whether the shift range of the automatic transmission is the N range or the D range. Then, a map corresponding to the determined shift range is selected from the N range map and the D range map shown in FIG. 8 (A), and detected by the water temperature sensor 24 based on the selected map. Based on the coolant temperature THW, calculate the reference value QI PAS B of the start-up expected correction term (S 610). Next, it is judged whether or not the timer counter T s exceeds the holding time CQ IP OF of the start initial expected correction term set to keep the initial correction term at the initial start constant (S 620). . The timer counter T s is a timer counter which is counted up during the independent operation of the engine 1 as described later. In addition, a value corresponding to, for example, about 1 to 10 seconds is set as the holding time CQIP F F of the startup initial expected capture positive term. The engine self-sustaining operation refers to a state in which the engine is not stalled after the engine 1 starts and the starter switch 43 is off.

If T s ≤ CQ IP OF (“NO” in S 620), the QI PAS initial correction term is the reference value QI PAS B of the initial startup correction term calculated in step S 610. It is set (S 630). Thus, the calculation process of the initial start estimated correction term Q I PAS is temporarily output. When the self-sustaining operation of engine 1 continues and T s C CQ I POF ("YES" in S 620), the initial start correction term QI PAS is calculated according to the following formula 12 (S 640).

Q I P A S

Q I PASB-(T s-CQ I POF) X Q I PASDL

... [Equation 12] Here, the decrease range QI PASDL is a value that sets the speed at which the start initial correction correction term QI PAS decreases according to the elapsed time of the self-sustaining operation. Next, it is determined whether the start-up expected correction term QI PAS is set to be negative (S 650). If QI PAS 0 0 ("NO" in S 650), the calculation process of QI PAS is started. If the QI PAS value is 0 (“YES” in S 650), set “0” to the QI PAS (S 660), and the QIP PAS QIPAS Exit the calculation process of. After that, as long as the ECU 44 is powered on, the condition that the start-up initial correction value QI PAS is zero is maintained. That is, after the engine 1 is started, the initial start correction term QI PAS is reduced by repeating the process of step S 640 after a certain fixed state for a while, and finally the initial start is started. Probability adjustment term QIP AS will substantially disappear. Next, the process of counting the timer counter T s will be described. Figure 11 shows a flowchart of the timer counter Ts counting process. The timer counter Ts counting process is a process which is repeatedly executed by an interrupt at every constant short time as well as idle time. When this process is started, first, it is determined whether or not it is the first process after the ECU 44 is powered on (S 710). If this time is the first process ("YES" in S71 0), the timer counter Ts is cleared to "0" (S720). If not the first time ("NO" in S710), the value of the timer counter Ts is maintained. After step S720, or when it is determined in step S710 that "N", it is next determined whether the engine 1 is in a self-sustaining operation (S730). If not in stand-alone operation ("NO" in S 730), that is, engine 1 is stopped, starter switch 43 is on even if engine 1 is rotating, or engine stalled. In this case, the process is temporarily ended. If the self-sustaining operation is being performed ("YES" in S730), the timer counter Ts is counted up as shown in the following equation 13 (S740).

T s — T s + 1 ··· [Equation 1 3]

Next, it is determined whether the timer counter T s has exceeded the upper limit value TMX (S 750). As the upper limit TMX, for example, a value corresponding to 10 minutes to 60 minutes is set.

If T s ≤ T M x (“NOj” at S 750), the process ends once T s TM T Mx (“YES” at S 750), the upper limit value TMX is set to the timer counter T s (S 760). Thus, the present process ends. Therefore, when the engine 1 is in a self-sustaining operation, the timer counter Ts counts up, and when it reaches the upper limit value TMX, the value of the timer counter Ts becomes constant in the state of the upper limit value TMX. Furthermore, when the engine 1 in a stand-alone operation is stopped due to an engine stall or the like (“NO” in S 730), the value of the timer counter T s maintains the value at the engine stall. Then, when the engine is started again to start the autonomous operation, the timer counter Ts starts counting up from the value maintained at the engine stall. An example of the process according to the first embodiment is shown in the timing chart of FIG. The starter operates at time t1 and the engine 1 starts to rotate. After that, the starter is turned off by starting the engine 1 (time t 2). This causes engine 1 to rotate independently (after time 2). The timer counter Ts starts counting up from this time t2. However, until the timer counter T s exceeds the holding time CQ IP OF of the start estimation correction term, the start estimation correction term QI PAS maintains the value of QI PAS B already set at startup. Then, when the timer counter T s exceeds the holding time CQ I POF of the start-up expected correction term (time t 3), the start-up expected correction term QI PAS gradually decreases and finally becomes “0”, substantially Disappear (Hiroshi l "t 4). As described above, since the load due to the large friction occurring at the initial stage of starting the engine 1 is compensated by the QI PAS, the integral correction term QII does not increase significantly as shown by the solid line. If the QI PAS is not provided, the integral correction term QII changes significantly, as indicated by the alternate long and short dash line. Therefore, it is impossible to set the upper limit guard value QII GM X low as in the present embodiment. Also, Fig. 13 shows the case where an engine stall occurs after starting. At time ij t 1 1, the starter is turned on, and at time t 1 2, the starter is switched from on to off. As a result, as described in FIG. 12, the timer counter T s starts counting up (after time t 12), and the holding time of the initial initial correction item is after CQIPOF. QI PAS starts to decrease (after time t 13). If the engine stall is caused at time t14, counting up of the timer counter Ts stops, and along with this, the decrease of the initial start correction item QI PAS also stops (after time t14). At this time, the values of the timer counter T s and the initial start correction term Q I PAS are maintained. And again, when the engine 1 starts to rotate independently by the operation from turning on the starter to turning off (Oh Ut 15 to t 16), the timer counter T s Start counting up again from the value maintained at the time of the engine start, and along with this, start decreasing again from the value maintained at the time of engine stall. t 1 6 onwards). In the above-described first embodiment, steps S 240 to S 260 in the I SC process (FIG. 4) correspond to the process as integral correction term calculation means, and the calculation process for the expected initial capture parameter QI PAS Fig. 10) and the counting process of the timer counter T s (Fig. 11) correspond to the process as the setting means of the estimation correction term at the time of start, and the steps S 120, S 1 30 corresponds to processing as fuel supply amount calculation means. According to the first embodiment described above, the following effects can be obtained.

(1) In the first embodiment, as described above, QIPAS is specifically provided for the start-up expected correction term, and the fuel injection amount is subjected to the expected correction corresponding to the friction existing at the start of engine 1 start-up. ing. For this reason, the engine speed NE can be converged to the idle target speed NETRG before the deviation of the actual engine speed NE from the idle target speed NETRG is largely accumulated in the integral correction term QII. . As described above, since it is possible to suppress the increase of the integral gain term QII, the control range of the integral correction term by the guard processing can be narrowed. In the first embodiment, the upper limit guard value QII GMX can be particularly reduced. Therefore, it is possible to compensate for the friction at the initial stage of the engine start to prevent the engine speed NE from falling and to effectively prevent the integral correction term QII from becoming excessive due to the half clutch and the like. Therefore, it is possible to prevent a sudden increase in engine speed in idle speed control. (2) Start-up initial estimate correction term QI PAS is set at start-up, and after being kept constant for a while, is gradually reduced. In the first embodiment, it decreases with the passage of time. As engine rotation continues, the friction at the initial stage of engine start disappears gradually. Therefore, by reducing the QI PAS based on the passage of time, the substantial correction by the QI PAS is stopped without causing a shock, and the idle rotation thereafter is performed. The number control can be taken over smoothly. In addition, since the value of QI PAS for the initial start correction term is not changed until the retention time CQ IP OF of the initial start expected capture term has passed, the initial value of the initial start correction term QI PAS is extremely set. Even if it is not large, it is possible to effectively suppress the increase of the integral correction term QII immediately after the start of the engine 1.

(3) In the case of engine stall, the friction at the initial stage of starting, which has been reduced by the rotation of engine 1 just before that, has hardly been recovered. For this reason, when restarting after an engine stall, the initial initial correction item for start-up, Q I PAS, is set to the value at engine stall and processing is started from this value. This makes it possible to properly set the initial start correction term Q I PAS and to make the idle speed control more stable.

(4) The size of the friction at the initial stage of engine start changes depending on the shift position of the transmission and the engine temperature. From this, the reference value QI PASB, which is the initial value of QI PAS, is switched according to the shift position of the transmission and the coolant temperature THW. As a result, the QI PAS can be properly adjusted. The idle speed control can be made more stable.

(5) Integral correction term QII guard processing (Fig. 6), the integral correction term control range is set by the upper limit guard value QII GMX and the lower limit guard value QII GMN based on the integral correction term learning value QIXM. It is done. Therefore, it is possible to appropriately guard the integral correction term Q I I which tends to fluctuate around the integral correction term learning value Q I XM. As a result, the control range of the integral correction term can be set appropriately, and idle speed control can be made more stable. Second Embodiment

In the second embodiment, unlike the first embodiment, the calculation of the initial startup correction term Q I PAS shown in FIG. 10 is not performed. Therefore, in step S 510 of the ISC estimate correction term calculation process (FIG. 7), the cold correction term QIPBCL, the electric load correction term QIP BDF, the air conditioner correction term QIPB AC, and the power steering correction term QIPBS , Load capture term QI PB is calculated. Furthermore, step S 280 of the I SC process (FIG. 4) is not performed, and instead, the guard value setting process as shown in the flowchart of FIG. 14 is performed as a separate process. Also, in place of the calculation process of the integral capture positive term learning value QI XM (FIG. 5), the calculation process of the integral correction term learning value QI XM shown in FIG. Is different. The other configuration is the same as that of the first embodiment unless otherwise described. The guard value setting process (Fig. 14) will be described. This process is a process that is repeatedly performed every fixed short time.

First, the timer counter T s exceeds the start initial guard holding time CQ I GO F It is judged whether or not it is present (S 8 1 0). Here, the start initial guard holding time CQ IG OF is set to a value corresponding to, for example, about 1 to 10 seconds.

If T s ≤CQ I GO F (“N 8” in S 8 10), then the upper limit guard value Q I I GMX is set to the upper limit guard initial value Q I I GMXS (S 820). The upper limit guard initial value Q I I GMXS is set to such a size that the integral correction term Q I I can absorb the friction component at the initial stage of engine start. Then, the lower limit guard value Q I I GMN is set to the lower limit guard value Q I I GMN (S 830). The lower limit guard initial value Q I I GMNS is set to such an extent that the integral correction term Q I I becomes too low for some reason at the initial stage of engine start and engine stall does not occur. Thus, the present process ends. Therefore, as long as T s CQ I GOF (“NO” in S 8 10), upper limit guard value QII GMX is maintained at QII GMXS (S 820) and lower limit guard value QII GMN is maintained at QII GMNS (S 8 3 0). If T s> CQ I GOF due to the timer counter T s counting up (“YE SJ” in S 8 10), the upper limit guard value Q I I GMX is calculated as in the following equation 14 (S 840).

Q I I GMX one

QII GMXS-(TS-CQ I GOF) XQ I GMXDL ... [Equation 1 4] Here, the decrease range QI GMXDL sets the speed at which the upper limit guard value QII GMX is decreased according to the freestanding operation time. The value is Next, the upper limit guard value QII GMX calculated in this way is the normal upper limit It is determined whether it is smaller than the threshold value QII GMXB (S 850). If QII GMX <QII GMXB ("YES" in S850), set the upper limit guard value QIIG MX to the normal upper limit guard value QII GMXB value (S860). If QIIG MX Q QII GMXB ("NO" in S 850), upper limit guard value QI

The value of I GMX maintains the value calculated in step S 840. After step S 860 or when it is determined in step S 850 that “N N”, the lower limit guard value Q I I GMN is calculated as in the following equation 15 (S 870).

Q I I GMN

QII GMNS-(T s-CQ I GOF) XQ I GMNDL ... [Equation 15] Here, the decrease range QI GMNDL sets the speed at which the lower limit guard value QII GMN is decreased according to the freestanding operation time. Value. Next, it is determined whether the lower limit guard value Q I I GMN thus calculated is smaller than the normal lower limit guard value Q I I GMNB (S 880). In the case of Q I I GMN or Q I I GMNB (“YES” in S 880), the lower limit guard value Q I I GM MN is set to the normal low limit guard value Q I I GMNB value (S 890). If Q I G MN QQ I I GMNB (“NOj” in S 880), the lower limit guard value Q I I GMN is maintained at the value calculated in step S 870.

After step S 890 or when “NO” is determined in step S 880, the present process ends.

Next, calculation processing of the integral correction term learning value QI XM (FIG. 15) will be described. In this process, the process of steps S 91 1 to S 91 5 is the same as the process of steps S 271 to S 275 of the integral correction term learning value QI XM calculation process (FIG. 5) in the first embodiment. . When this process is started, first, whether the upper limit guard value QII GMX has reached the normal upper limit guard value QII GMXB and the lower limit guard value QII GMN has reached the normal lower limit guard value QII GMNB or not Is determined (S 910). If either or both of QII GMX MX QII GMXB and QII GMN MN QII GMN B (“N」 ”in S 9 10), the current integral correction term learning value QI XM (i) The previous integral correction term learning By setting the value QI XM (i-1) (S915), the integral correction term learning value QI XM is maintained so as not to fluctuate. If the previous control cycle and the current control cycle are in an idle state different from each other due to external load switching, etc., the integral correction term learning value QI XM (i) in the current control cycle is The most recent integral correction term learning value QI XM in the same idle state as the time is set. On the other hand, if QII GMX = QII GMXB and QII GMN = QII GMNB ("YES" in S 910), then the process starts from step S 91 1 and thereafter, the process described in the first embodiment. As described above, the process of calculating the integral correction term learning value QI XM (S 9 11 to S 91 5) is executed, and the integral correction term learning value Q I X M will be changed to an appropriate value by learning. . An example of the process according to the second embodiment is shown in the timing chart of FIG. The starter operates at time t 21 and the engine 1 starts rotating. Thereafter, the starter is turned off by starting the engine 1 (time t22). Due to this, the engine 1 starts to rotate independently (after time t22). From time t22, the timer counter Ts starts counting up. However, until the timer counter T s exceeds the start initial guard holding time CQIG F F, the upper limit guard value QII GMX maintains the value of the upper limit guard initial value QII GMXS already set at the start, and the lower limit guard value QII The GMN maintains the value of the lower limit initial value QII GMNS already set at startup. Then, when the timer counter T s exceeds the initial initial guard holding time CQIG F F (time IJ t 2 3), the upper limit guard value QII GMX and the lower limit guard value QII GMN gradually decrease and finally the upper limit guard value The QII GMX normally becomes the upper limit guard value QII GMX B (time t 2 5), and the lower limit guard value Q I. I GMN becomes the normal lower limit guard value Q II GMN B (time t 2 4). Even if the integral correction term QII increases to compensate for the load due to the large friction that occurs at the beginning of starting the engine 1, the guard value, especially the upper limit guard value QII GMX, is temporarily set at the start and immediately after the start. Is set large. For this reason, it is possible to sufficiently execute the fuel injection amount compensation for the friction at the initial stage of the start. Thereafter, the upper limit guard value QII GMX and the lower limit guard value QII GMN are both reduced to match the decrease in friction at the initial stage of startup, and finally the normal upper limit guard value QII GMX B and the normal lower limit guard value QII It becomes GMN B. Therefore, the upper limit guard value QII GMX and the lower limit guard value QII GMN never continue to be large. Figure 17 shows the case where an engine stall occurs after start-up. By turning on the starter at time t 31 and turning off the starter at time t 32, the timer counter T s starts counting up in the same manner as described in FIG. After the initial initial guard holding time CQIGOF, decrease of upper limit guard value QII GMX and lower limit guard value QII GMN is started (after time t 33). ■ However, when an engine stall occurs at time t 34, the timer counter T s stops counting up, and along with this, the upper limit guard value QII GMX and lower Limited guard value QII GMN reduction also stops (from time i t 34 onwards). At this time, the timer 1 counter T s, the upper limit guard value QII GMX, and the lower limit guard value QII GMN are maintained at that value. Then, when the engine 1 rotates independently by the operation of turning the starter on and off again (time t 35 to t 3 6), the timer counter T s counts again from the value maintained at the time of engine stall. As a result, the upper limit guard value QII GMX and the lower limit guard value QII GMN start decreasing again from the value maintained at the time of engine stall (after time t36). Finally, the upper limit guard value QII GMX becomes the normal upper limit guard value QII GMX B (time t 3 8), and the lower limit guard value Q II GMN becomes the normal lower limit guard value Q II GMNB (time t 37). In the second embodiment described above, steps S 240 to S 270 and S 290 in the I SC process (FIG. 4), guard value setting process (FIG. 14) and timer counter T s count process (FIG. 11) The step S 120 and step S 130 of the fuel injection amount control process (FIG. 2) correspond to the process as the fuel supply amount calculation means, and the integral correction term learning value The QI XM calculation process (Fig. 15) corresponds to the process as the integral correction term learning means. According to the second embodiment described above, the following effects can be obtained.

(1) The control range of the integral correction term, that is, the interval between the upper limit guard value QII GMX and the lower limit guard value QII GMN, is set wider than in the normal operation at the start of engine 1 and immediately after the start. In particular, the upper limit guard value QII GMX is increased. Therefore, it is possible to allow the value of the deviation of the actual engine speed NE with respect to the idle target engine speed NETRG to be largely accumulated in the integral correction term QII at the start of the engine 1 or immediately after the start. Therefore, when starting and immediately after starting In the latter case, the integral correction term QII compensates for friction at the start of engine startup and prevents engine speed NE from falling. Then, at the time of idle speed control at a later time, the control range of the integral correction term is returned to the width at the time of normal operation, so that the integral correction term QII is prevented from becoming excessive. Soaring is prevented.

(2) The upper limit guard value Q I I GMX and the lower limit guard value Q I I GMN maintain the value for a while, and then gradually reduce the control range of the integral correction term by decreasing them gradually according to the elapsed time. This is because as the engine 1 continues to rotate, the friction at the initial stage of engine start gradually disappears, so the integral correction term Q I I becomes smaller gradually. Therefore, by gradually narrowing the control range of the integral correction term according to the elapsed time, it is possible to return to the control range of the integral correction term during normal operation and smoothly take over to the idle speed control thereafter. Furthermore, by providing a period for maintaining the control range of the integral correction term in the initial stage, the integral correction term QII can be obtained without extremely widening the control range of the integral correction term at engine start or immediately after start. Allow time for sufficient rise. By this, it is possible to effectively compensate for the friction in the initial stage of the engine start by the integral correction term QII.

(3) In the situation where the control range of the integral correction term is set wider than in normal operation, the integral capture term QII fluctuates significantly. From this, it is not appropriate to carry out the calculation of the integral correction term learning value QI XM because it is prone to errors. Therefore, calculation of the integral correction term learning value QI XM is prohibited before the control range of the integral correction term returns to the normal operation range, and when the control range returns to the normal operation range, the integral correction term learning value QI XM Allow calculation. This makes the error of the integral correction term learning value QI XM effective. It becomes possible to suppress the idle speed automatically, which enables more stable idle speed control.

(4) In the case of engine stall, since the friction at the initial stage of starting reduced by the previous rotation of the engine 1 is hardly recovered, the integral correction term Q I I also needs to remain large. Therefore, when restarting after an engine stall, the control range of the integral correction term is set to the width at the time of engine stall, and processing is started from this state. As a result, the control range of the integral correction term can be set appropriately, and idle speed control can be made more stable.

(5) As in the first embodiment, the control range of the integral correction term can be set appropriately, and idle speed control can be made more stable.

Other embodiments

The configurations of the first embodiment and the second embodiment may be combined. That is, the start initial expectation correction term QI PAS (FIG. 10) of the first embodiment is executed with respect to the configuration of the second embodiment to calculate the start initial expectation correction term QI PAS. And be added to the load capture term QI PB. Then, for example, the same initial value is used for the start initial guard holding time CQIGOF and the holding time CQ I POF of the start initial estimated correction term used in the guard value setting process (FIG. 14). Then, the timing at which the start initial correction item QIP AS becomes "0", the timing when the upper limit guard value QII GMX becomes the normal upper limit guard value QII GMXB, the lower limit guard value QII GMN becomes the normal lower limit guard value QII GMNB The reduction width QI PAS DL in the above equation 12, the reduction width QI GMXDL in the above equation 14, and the reduction width QI GMNDL in the above equation 15 are set so that the timing becomes substantially the same. With this configuration, both the application of QIPAS and the expansion of the control range of the integral correction term are performed at the start and immediately after the start, and then the disappearance and integration of the QIPAS and the initial correction term The reduction of the control range of the correction term is performed in conjunction with this. This makes it possible to sufficiently compensate the integral correction term QII even if the compensation for the friction in the initial stage of the start is insufficient with the value of QIPAS at the initial start estimation correction immediately after start up. Therefore, idle speed control can be made more stable. Although the start initial expected capture term QIPAS of the first embodiment and the guard values QII GMX and QII GMN of the second embodiment are set according to the value of the timer counter T s, the engine speed NE It may be set according to the integrated rotation speed. This is because the friction at the beginning of the start is attenuated as the engine is rotated at the time of start and after start. Also, according to the increase of the cooling water temperature THW, the QIPAS correction term and the guard value QII GMX, QII GMN may be set. As the engine operation continues from the start, the coolant temperature THW gradually rises. Such a temperature rise pattern is similar to the friction reduction pattern at the initial stage of engine start, and such a temperature factor is also involved in the magnitude of the friction at the initial stage of engine start. In each of the above-described embodiments, the timer counter T s has started to increase at the timing when the starter 1 switches from on to off and the engine 1 starts completely self-sustaining. The timer may be counted up at the timing when the engine 1 starts to rotate by the starter. In addition, even when the starter is in the on state, the timer counter Ts may count up when the number of revolutions rises above the reference number of revolutions. In the first embodiment, the reference value QIPASB of the initial start estimated correction term is The setting is made according to the shift of the automatic transmission and the cooling water temperature THW, but it may be set according to the type of external load such as air conditioning and power steering and the presence or absence thereof. In the second embodiment, fixed values are used for the upper limit guard initial value QII GMX S and the lower limit guard initial value QII GMN S, but may be set according to the shift of the automatic transmission and the coolant temperature T HW. It may be set according to the type of external load such as air conditioner and power steering, and the presence or absence.

Claims

The scope of the claims

1. When the internal combustion engine is idle, the integral correction term is calculated based on the deviation of the actual internal combustion engine speed from the target rotational speed, and the fuel supply amount is corrected using the integral correction term, so that the internal combustion engine idles. An idle fuel supply control method for controlling the number of revolutions

At the time of starting of the internal combustion engine and / or immediately after the start of the internal combustion engine, control of the idle fuel supply amount is performed by performing an expected correction corresponding to the friction existing in the initial stage of the internal combustion engine start. Method.

2. The idle fuel supply amount according to claim 1, characterized in that the estimated correction is performed by gradually reducing the estimated correction term set at one or both of starting and immediately after starting the internal combustion engine. Control method.

3. The idle fuel supply control method according to claim 2, wherein a period for holding the value of the estimated correction term is provided before the estimated correction term is gradually reduced.

4. The idle fuel supply amount control method according to claim 2, wherein the estimated correction term is gradually reduced according to an elapsed time after start or start of rotation of the internal combustion engine.

5. The idle fuel supply according to claim 2 or 3, wherein the estimated correction term is gradually reduced according to the integrated number of revolutions of the internal combustion engine after the start of the rotation of the internal combustion engine or after the start thereof. How to control the quantity.

6. The idle fuel supply control method according to claim 2 or 3, wherein the estimated correction term is gradually reduced according to the temperature rise of the internal combustion engine.

7. The method of controlling an idle fuel supply amount according to claim 6, wherein the temperature of the internal combustion engine is a coolant temperature of the internal combustion engine.

8. In restart after engine stall, the expected correction term is set to the value at engine stall, and the reduction is started from this value. The control method of the amount of idle fuel supplies as described in any one.

9. The idle fuel supply amount control method according to any one of claims 1 to 8, characterized in that the expected positive correction is switched according to a shift position of a transmission.

10. The idle fuel supply amount control method according to any one of claims 1 to 8, wherein the estimated correction term is switched according to the presence or absence of an external load.

The idle fuel supply amount control method according to any one of claims 1 to 8, wherein the estimated correction term is switched according to the type of external load.

1 2. Calculate the integral correction term based on the deviation of the actual number of revolutions of the internal combustion engine from the target number of revolutions when the internal combustion engine is idle, and guard against the upper limit guard value and the lower limit guard value for the integral correction term. It is a control method of idle fuel supply amount that controls the idle speed of an internal combustion engine by performing processing and correcting the fuel supply amount using the integral correction term after the guard processing.

The control range of the integral correction term between the upper limit guard value and the lower limit guard value is set wider than that in the normal operation at one or both of the start of the internal combustion engine and immediately after the start. To control the amount of idle fuel supply.

1 3. The guard process is performed at one or both of starting and immediately after starting the internal combustion engine. The method of controlling an idle fuel supply amount according to claim 12, wherein the control range of the set integral correction term is gradually narrowed to a range at the time of normal operation.

A fuel cell system according to claim 13, wherein a period for maintaining the control range of the integral correction term is provided before the control range of the integral correction term is gradually narrowed. Control method.

The idle fuel supply amount according to claim 13 or 14, characterized in that the control range of the integral correction term is gradually narrowed according to an elapsed time after start or start of rotation of the internal combustion engine. Control method.

16. The idle according to claim 13 or 14, characterized in that the control range of the integral correction term is gradually narrowed according to the integrated rotational speed of the internal combustion engine after the start of rotation or after the start of rotation of the internal combustion engine. How to control fuel supply.

The control method of the idle fuel supply amount according to claim 13 or 14, characterized in that the control range of the integral capture term is gradually narrowed according to the temperature rise of the internal combustion engine.

The method according to claim 17, wherein the temperature of the internal combustion engine is a coolant temperature of the internal combustion engine.

In restart after engine stall, the control range of the integral correction term is set to the range at engine stall, and processing for gradually narrowing the range from the range is started. The control method of the idle fuel supply according to any one of 18.

20. The control method of the idle fuel supply amount according to any one of claims 12 to 19, wherein a control range of the integral correction term is switched according to a shift position of a transmission.

21. The control method of the idle fuel supply amount according to any one of claims 12 to 19, wherein the control range of the integral correction term is switched according to the presence or absence of an external load.

The control range of the integral correction term is switched according to the type of the external load, The idle fuel supply control method according to any one of claims 12 to 19.

2 3. The control range of the integral acquisition term is set with the learning value of the integration correction term as a reference position, according to any one of claims 12 to 22. Control method of idle fuel supply amount.

The calculation of the learning value of the integral correction term is permitted when the control range of the integral correction term is returned to the range at the time of normal operation. The control method of idle fuel supply according to any one of the preceding claims.

The integral correction term is calculated based on the deviation of the actual number of revolutions of the internal combustion engine from the target number of revolutions when the internal combustion engine is idle, and the upper limit guard value and the lower limit guard value are used as a guard for the integral correction term. It is a control method of an idle fuel supply amount which controls an idle rotation speed of an internal combustion engine by performing a processing and correcting a fuel supply amount using the integral correction term after the guard processing.

At one or both of the start of the internal combustion engine and immediately after the start, an expected correction corresponding to the friction existing at the start of the start of the internal combustion engine is performed on the fuel supply amount. The idle fuel supply amount is set by performing both of the process of setting the control range of the integral correction term between the upper limit guard value and the lower limit guard value wider than in the normal operation. Control method.

6 6. While the expected correction term substantially exists, the control range of the integral correction term between the upper limit guard value and the lower limit guard value is set wider than in normal operation. The idle fuel supply control method according to claim 25.

27. The control range of the integral correction term between the upper limit guard value and the lower limit guard value is gradually narrowed toward the normal operation range in conjunction with the reduction of the estimated correction term. The idle fuel supply control method according to claim 25.

28. The method of controlling an idle fuel supply amount according to any one of claims 1 to 28, wherein the internal combustion engine is configured as a diesel engine.

First calculation means for calculating an integral correction term based on the deviation of the actual number of revolutions of the internal combustion engine from the target number of revolutions when the internal combustion engine is idle,

Setting means for setting an expected correction term corresponding to a friction existing at an initial stage of starting the internal combustion engine at one or both of the start of the internal combustion engine and immediately after the start of the internal combustion engine;

The fuel supply amount is calculated by correcting the basic fuel amount with the correction term including the integral correction term calculated by the first calculation means and the vision correction term set by the setting means. Second calculation means,

A controller for idle fuel supply amount, which controls an idle speed of an internal combustion engine by providing an internal combustion engine.

3 0. The setting means gradually reduces the estimated correction term set at one or both of the start of the internal combustion engine and the time immediately after the start of the internal combustion engine. Control of idle fuel supply.

31. The control of the idle fuel supply amount according to claim 30, wherein the setting means sets a period for holding the value of the estimated correction term before gradually reducing the estimated correction term. apparatus.

3 2. The idle fuel supply according to claim 3, wherein the setting means gradually reduces the possibility correction term according to an elapsed time after start or start of rotation of the internal combustion engine. Amount of control device.

3 3. The setting means gradually reduces the estimated correction term according to the integrated rotational speed of the internal combustion engine after the start of the rotation of the internal combustion engine or after the start thereof. Control device for the described idle fuel supply.

The idle fuel supply control device according to claim 30 or 31, wherein the setting means gradually reduces the estimated correction term according to the temperature rise of the internal combustion engine.

The control apparatus according to claim 34, wherein the setting means uses a coolant temperature of an internal combustion engine as the temperature of the internal combustion engine.

The setting means sets, in the restart after engine stall, the estimated correction term to a value at the time of engine stall, and starts the reduction from the value. The control of the idle fuel supply according to any one of

3 7. The setting means turns off the possibility correction term according to the shift position of the transmission. An idle fuel supply control device according to any one of claims 29 to 36, characterized in that it is replaced.

38. The control apparatus according to any one of claims 29 to 36, wherein the setting means switches the estimated correction term according to the presence or absence of an external load.

39. The idle fuel supply control device according to any one of claims 29 to 36, wherein the setting means switches the estimated correction term according to the type of external load.

4 0. The integral correction term is calculated based on the deviation of the actual number of revolutions of the internal combustion engine from the target number of revolutions when the internal combustion engine is idle, and the upper limit guard value and the lower limit guard value for the integral correction term are guarded While performing processing, at one or both of starting of the internal combustion engine and immediately after starting, the control range of the integral correction term between the upper limit guard value and the lower limit guard value is set wider than in normal operation. A second calculation means for calculating the fuel supply amount by correcting the basic fuel amount with a correction term including the integral correction term calculated by the first calculation means;

A controller for an idler fuel supply amount that controls an idle speed of an internal combustion engine by providing an internal combustion engine.

4 1. In the guard process, the first calculation means gradually narrows the control range of the integral correction term set at one or both of the start of the internal combustion engine and immediately after the start of the internal combustion engine, The controller for the idle fuel supply amount according to claim 40, characterized in that:

4 2. The first calculation means is configured to reduce the control range of the integral correction term gradually. A period is provided to maintain the width of the control range of the integral correction term.

The control device for the idle fuel supply amount according to 4. .

4 3. The first calculation means is characterized in that the control range of the integral correction term is gradually narrowed according to the elapsed time after the start of rotation of the internal combustion engine or after the start of the internal combustion engine. The idle fuel supply control device according to claim 1.

4. The first calculation means is characterized in that the control range of the integral correction term is gradually narrowed in accordance with the integrated rotational speed of the internal combustion engine after the start of rotation of the internal combustion engine or after the start of rotation of the internal combustion engine. The idle fuel supply control device according to 1 or 4 2.

The idle fuel supply system according to claim 41, wherein the first calculation means gradually narrows the control range of the integral correction term in accordance with the temperature rise of the internal combustion engine. Amount of control device.

The control device according to claim 45, wherein the first calculation means uses a cooling water temperature of an internal combustion engine as a temperature of the internal combustion engine.

4 7. In the restart after engine stall, the first calculation means sets the control range of the integral capture positive term to the range at the time of engine stall and starts the process of gradually narrowing from the range. The controller for the idle fuel supply amount according to any one of claims 4 to 6, wherein

The first calculation means switches the control range of the integral correction term in accordance with the shift position of the transmission, according to any one of claims 40 to 47. Control unit for idle fuel supply.

The idle fuel supply according to any one of claims 40 to 47, wherein the first calculation means switches the control range of the integral correction term according to the presence or absence of an external load. Amount of control device.

5 0. The idle fuel supply according to any one of claims 40 to 47, wherein the first calculation means switches the control range of the integral correction term according to the type of external load. Amount of control device.

51. The first calculation means sets a control range of the integral correction term on the basis of a learning value of the integral correction term, according to any one of claims 40 to 50. Control unit for idle fuel supply.

5 2. The system further comprises integral correction term learning means for executing calculation of the learning value of the integral correction term when the control range of the integral correction term in the first calculation means returns to the range of normal operation. The idler fuel supply control device according to any one of claims 40 to 51, characterized in that:

5 3. Calculate the integral positive term based on the deviation of the actual number of revolutions of the internal combustion engine from the target number of revolutions when the internal combustion engine is idle, and calculate the integral correction term using the upper limit guard value and the lower limit guard value. Guard processing is performed, and at one or both of starting of the internal combustion engine and immediately after starting, the control range of the integral correction term between the upper limit guard value and the lower limit guard value is set wider than that in normal operation. First calculating means, setting means for setting an expected correction term corresponding to a friction present at an initial stage of starting the internal combustion engine, at one or both of starting and immediately after starting the internal combustion engine;

The fuel supply amount is calculated by correcting the basic fuel amount with a correction term including the integral correction term calculated by the first calculation means and the vision correction term set by the setting means. Two calculation means, A controller for an idler fuel supply amount that controls an idle speed of an internal combustion engine by providing an internal combustion engine.

5 4. The first calculation means sets the control range of the integral correction term between the upper limit guard value and the lower limit guard value wider than that during normal operation while the expected correction term substantially exists. The control of the idle fuel supply amount according to claim 5 characterized by

The first calculation means is linked to the reduction of the expected correction term by the setting means to control the control range of the integral correction term between the upper limit guard value and the lower limit guard value during normal operation. The idle fuel supply control device according to claim 53, wherein the fuel supply amount is gradually narrowed toward the range.

The control device for the idle fuel supply amount according to any one of claims 29 to 55, wherein the internal combustion engine is configured as a diesel engine.