JP2007085199A - Idle rotation control apparatus for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an idle rotation control apparatus for an internal combustion engine, which enables the rotational stability and the reduction of the fuel consumption during the idling rotation. <P>SOLUTION: The idle rotation control apparatus is provided with an idle rotational speed setting means A1 for setting the idle rotational speed NADa of the engine 1 equipped with a supercharger 9, a vehicle velocity sensor 50 to detect a vehicle speed Vc of the vehicle mounting the engine 1, an accelerator opening sensor 31 to detect an accelerator opening θa, a vehicle stop maintenance condition detection means 41 for detecting that the vehicle is in the stop maintenance condition, and an engine control means A4 for opening a waste gate valve 29 annexed to the supercharger 9 while controlling the idle rotational speed to a low idle rotational speed NADL by the predetermined decreasing amount dN when the vehicle speed is zero, the accelerator opening is totally closed, and the rotation reducing permissible condition is satisfied that it is in the stop maintenance condition. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an idle rotation control device for an internal combustion engine that can reduce the rotation while maintaining stabilization of the idle rotation of the internal combustion engine.

  The internal combustion engine is operated while being held at an idle speed during no-load operation, and at that time, in order to maintain a reduction in fuel consumption and a reduction in noise, control is performed to reduce and stabilize the idle speed.

  By the way, an internal combustion engine is equipped with a supercharger to improve output, and in particular, exhaust energy is recovered by an exhaust turbine, and the compressor of the intake passage is driven by the rotational force to supercharge intake air. As a result, exhaust superchargers that increase volumetric efficiency in the combustion chamber and improve output are frequently used. An engine equipped with such a supercharger is usually set at a higher idle rotation speed when operated in an idle rotation range than a naturally aspirated non-turbo engine without a supercharger. This is a measure for improving the response of a vehicle equipped with an engine with a supercharger. When a start operation is performed during idling, the turbine is set to a certain rotational speed in advance. It is made based on a request to improve the supercharging response.

However, when the countermeasure for setting the idling rotational speed to a high value is taken, this causes one reason that the fuel efficiency of the supercharger-equipped vehicle is poor.
Therefore, in Patent Document 1, in a diesel engine with a turbocharger, a wastegate valve attached to the turbocharger is opened during low load operation, exhaust resistance is reduced during low load operation, and pumping loss is reduced to reduce fuel consumption. I try to improve.

JP-A-5-312049

  However, the turbocharged engine disclosed in Patent Document 1 simply opens the wastegate valve in a preset low-load operation region to reduce exhaust resistance and improve fuel efficiency. Since the wastegate valve is closed, there is a problem that the loss time until the supercharging operation becomes long and the supercharging response is inferior.

  The present invention has been made based on the above problems, and an object of the present invention is to provide an idling rotation control device for an internal combustion engine capable of stabilizing rotation and reducing fuel consumption while ensuring supercharging response. It is in.

  An ignition timing control device for an internal combustion engine according to claim 1 of the present invention includes an idle rotation speed setting means for setting an idle rotation speed of the internal combustion engine, and a supercharger that performs a supercharging operation with the exhaust energy of the exhaust passage of the internal combustion engine. A wastegate valve attached to the vehicle, a vehicle speed sensor for detecting the vehicle speed of the vehicle equipped with the internal combustion engine, an accelerator opening sensor for detecting the accelerator opening of the vehicle, and the vehicle being in a stopped state. The vehicle stop maintaining state detecting means for detecting, and when the vehicle speed is zero, the accelerator opening is fully closed, and the rotation reduction allowable condition that the vehicle stop maintaining state is satisfied, opens the waste gate valve and And a control device that controls the idle speed to a low idle speed that is lower by a predetermined reduction amount.

  An ignition timing control apparatus for an internal combustion engine according to a second aspect of the present invention is the idle rotation control apparatus for an internal combustion engine according to the first aspect, wherein the control apparatus is configured so that a predetermined waiting time elapses when the rotation reduction allowance condition is satisfied. The waste gate valve is opened and the idle speed is controlled to the low idle speed.

  An ignition timing control device for an internal combustion engine according to a third aspect of the present invention is the idle rotation control device for the internal combustion engine according to the first or second aspect, wherein the control device is configured to provide the wastegate valve when the rotation reduction allowance condition is satisfied. After the engine is opened, the idle speed is controlled to the low idle speed.

  An ignition timing control device for an internal combustion engine according to a fourth aspect of the present invention is the idle rotation control device for an internal combustion engine according to the first, second, or third aspect, wherein the control device is an operating region in which the rotation reduction allowance condition is satisfied. When the accelerator opening is released under conditions other than the fully closed condition, the low idle speed is raised to the start standby speed and the wastegate valve is closed. To do.

  An ignition timing control apparatus for an internal combustion engine according to a fifth aspect of the present invention is the idle rotation control apparatus for an internal combustion engine according to the fourth aspect, wherein the control apparatus reduces the low idle when the rotation reduction allowance condition is released. When the rotational speed is increased toward the transient rotational speed that is a predetermined amount lower than the start standby rotational speed and the ignition timing of the internal combustion engine is advanced, the idle rotational speed reaches the transient rotational speed. The ignition timing is corrected to be retarded and the intake air amount of the internal combustion engine is corrected to be increased.

  According to claim 1 of the present invention, when the rotation reduction allowance condition that the vehicle speed is zero, the accelerator opening is fully closed, and the vehicle is in a stopped state is satisfied, that is, under the situation where the vehicle does not start immediately, Since the control means opens the waste gate valve and controls the idle speed to a low idle speed that is lower by a predetermined reduction amount, the exhaust resistance can be reduced by opening the waste gate valve, and the fuel efficiency can be improved, and the internal EGR is lowered and the rotation speed is reduced. Stabilization can be achieved and fuel consumption can be reduced by low idling speed. Also, in the operating range where the conditions for lowering the rotation speed are not satisfied, i.e., in situations where there is a possibility of starting immediately, the wastegate valve is closed and the normal idling speed is maintained, thereby reducing the responsiveness when requesting acceleration. Can be suppressed.

  According to the second aspect of the present invention, the waste gate valve is opened and the engine speed is corrected to a low idle speed after a predetermined waiting time has elapsed after the rotation reduction allowance condition is satisfied. Can be suppressed, and idle rotation can be prevented from varying.

  According to the third aspect of the present invention, since the idling speed is controlled after the waste gate valve is opened, the revolution speed is lowered after the combustion is stabilized due to the decrease in internal EGR due to the waste gate valve being opened. It is possible to reliably stabilize the rotation at the idling speed.

  According to the fourth aspect of the present invention, when the rotation reduction permission condition is released, the low idle rotation speed is raised to the start standby rotation speed and the wastegate valve is closed. Can be held.

  According to the fifth aspect of the present invention, when the rotation reduction permission condition is canceled and the low idle speed is raised to the start standby speed, the ignition is performed while reaching the transition speed at a predetermined amount lower than the start standby speed. The timing is advanced to ensure responsiveness of increased rotation. Further, when the engine speed reaches a transient speed, the ignition timing is retarded and the intake air amount is corrected to increase without exhausting the engine significantly. The flow rate can be increased efficiently and the turbine speed can be secured early.

  1 and 2 show a DOHC type four-cylinder engine (hereinafter simply referred to as engine 1) as an internal combustion engine to which an idle rotation control device for an internal combustion engine as an embodiment of the present invention is applied. In this apparatus, the engine 1 has an intake passage 3 and an exhaust passage 4 that communicate with the combustion chamber 2. The intake passage 3 and the combustion chamber 2 are provided by an intake valve 5, and the exhaust passage 4 and the combustion chamber 2 are provided by an exhaust. The valves 6 are controlled to communicate with each other.

  An air cleaner 7, an air flow sensor 8, a compressor 11 of the supercharger 9, an intercooler 12, a throttle valve 13, an intake manifold 14, and an electromagnetic fuel injection valve (injector) 15 are provided in the intake passage 3 from the upstream side. The exhaust passage 4 has an exhaust manifold 16, an exhaust pipe 17, a turbine 18 of the supercharger 9, a catalytic converter (three-way catalyst) 19 for exhaust gas purification, and a muffler (silencer) (not shown) from the upstream side. Is provided.

  The engine 1 is configured as an intake pipe injection type (MPI) engine 1, and a DOHC type is adopted as a valve operating mechanism thereof. Timing pulleys 23 and 24 are attached to the front ends of the intake camshaft 21 and the exhaust camshaft 22 on the cylinder head 101, and these timing pulleys are connected to a crankshaft 26 via a timing belt 25. As the crankshaft 26 rotates, the camshafts 21 and 22 are rotationally driven together with the timing pulleys 23 and 24, and the intake valve 5 and the exhaust valve 6 are driven to open and close by these camshafts.

Further, the air-fuel mixture in the combustion chamber 2 of the engine 1 is ignited by the spark plug 35, and the exhaust gas after combustion flows down from the exhaust port 16p to the exhaust passage 4 as the piston 10 rises when the exhaust valve 6 is opened. Then, it is discharged to the outside through a catalytic converter (three-way catalyst) 19 and a silencer (not shown).
The engine 1 is an in-line four-cylinder engine, and four spark plugs 35 are provided (only one is shown here), and each spark plug 35 is connected to an ignition driver 37 via an igniter 36. As a result, an ignition secondary voltage is sequentially supplied to each spark plug 35 by the action of an igniter 36 that receives an ignition signal from the ECU 27, which will be described later, to ignite the air-fuel mixture.

  The engine 1 is provided with branched intake manifolds 14 corresponding to the number of cylinders, each of which is provided with intake ports 14p, each having an injector 15 (only one is shown here), and each injector 15 is a fuel injection driver 151. And a so-called multipoint fuel injection (MPI) type multi-cylinder engine. The throttle valve (ETV) 13 is connected to an accelerator pedal (not shown) via a wire cable, so that the opening degree changes according to the depression amount θa of the accelerator pedal. Further, the throttle valve (ETV) 13 is connected to an idle speed control motor (ISC motor) 32 and an ETV driver 321, and is also opened and closed by this. Thus, the opening degree of the throttle valve 13 can be changed without stepping on the accelerator pedal during idling.

  With such a configuration, in accordance with the opening degree of the throttle valve (ETV) 13, the sucked air is mixed with the fuel from the injector 15 in the intake manifold 14 so as to have an appropriate air-fuel ratio, and in the combustion chamber 2. The ignition plug 35 is ignited and burned at an appropriate timing to generate engine torque. Exhaust gas in the combustion chamber 2 is discharged into the exhaust passage 4, harmful components are purified by the catalytic converter 19, silenced by the muffler, and released to the atmosphere side.

  Further, on the side of the intake passage 3 of the engine 1, an air flow sensor 8 for detecting the intake air amount (volume flow rate) Qa from Karman vortex information and an intake air temperature sensor for detecting the intake air temperature Ta are disposed in the air cleaner 7. 30 is provided, and a throttle sensor 33 or the like for detecting the throttle opening degree θs is provided at a portion where the throttle valve (ETV) 13 is disposed. Further, the engine 1 is provided with a water temperature sensor 34, a crank angle sensor 38 that detects the crank angle θb (this crank angle sensor also serves as a rotation speed sensor that detects the engine rotation speed Ne), and the like. This is input to an electronic control unit (ECU) 27 described later.

  The supercharger 9 is disposed between the intake passage 3 and the exhaust passage 4, and the impellers (not shown) of the turbine 18 and the compressor 11 are integrally connected to both ends of the rotary shaft 28 pivotally supported by the casing 901. The exhaust energy is recovered by the turbine 18 and the compressor 11 in the intake passage 3 is driven by the rotational force to supercharge the intake air, thereby increasing the volumetric efficiency in the combustion chamber 2 and improving the output. . Here, a wastegate valve 29 is mounted on the outer side of the casing 901 so as to open and close a bypass passage br that causes exhaust gas upstream of the turbine 18 to flow around the turbine 18 and flow downstream. The waste gate valve 29 is opened and closed by an electronic control unit (ECU) 27 via an electromagnetic actuator (not shown).

  On the downstream side of the compressor 11 of the supercharger 9 having such a configuration, an air-cooled intercooler 12 is arranged to lower the temperature of the intake air whose temperature has increased with the increase in pressure due to supercharging by the supercharger 9. Thus, the temperature of the intake air is lowered, and the volume efficiency of the engine 1 is improved.

  The electronic control unit (ECU) 27 includes a CPU 271, a ROM 272, a RAM 273, a nonvolatile DRAM 274, input / output interfaces 275, 276, and the like. The ECU 27 receives a signal related to the engine speed Ne from the engine speed sensor, a signal θa related to the depression depth of the accelerator pedal from the accelerator opening sensor 33, a water temperature signal wt from the water temperature sensor 34, an atmospheric temperature Ta from the atmospheric temperature sensor 30, and a vehicle speed. A vehicle speed signal Vc from the sensor 50 and a brake signal Bs from the brake switch 60 are input, and other signals are input from various sensors and actuators not shown in the drawing. Based on these various input signals, the ECU 27 performs control calculations to control the operation of the injector 15 and spark plug 35 of the engine 1, the throttle motor 32 of the ETV 13, and the like. In particular, the waste gate valve 29 of the supercharger 9 is controlled. Open / close control is performed.

The ECU 27 has a control function of the engine 1, and as shown in FIG. 2, in particular, an idle speed setting means A1, an idle speed correction value setting means A2, a low idle speed range determination means A3, an engine control means A4, And a function of the supercharger control means A5.
The idle speed setting means A1 sets an idle speed NADA (one of the engine speeds Ne) corresponding to the water temperature (atmosphere temperature) wt of the engine 1.

  The idle rotation speed correction value setting means A2 sets a low idle rotation speed NADL (NADn−dN) that lowers the idle rotation speed NADA (set to a start waiting rotation speed NADn, which will be described later) by a predetermined decrease dN. Set. Note that the decrease amount dN may be a constant value, and in some cases, a correction value map may be used so as to reduce the value according to the rise in water temperature.

  The low idle rotation region determination means A3 takes in the current driving information, of which the vehicle speed Vc is zero, the accelerator opening θa is fully closed, the brake signal Bs is turned on, and the above three conditions for allowing rotation reduction are satisfied. If it is not satisfied, the idle speed NADA (here, preset as the start standby speed NADn) is selected, and if the rotation reduction allowance condition is satisfied, the low idle speed NADL is selected. To do. Here, in order to detect the vehicle stop maintaining state, it is determined that the brake signal Bs is turned on assuming a vehicle with an automatic transmission. However, in the case of a vehicle with a manual transmission, the neutral switch 41 is used instead. If the neutral signal Hs is present, the configuration may be changed so that it is determined that one of the conditions for allowing rotation reduction is satisfied. Further, as another method for detecting the stoppage maintenance state, both the brake signal on and the neutral signal are detected. It is also possible to set that the rotation reduction allowance condition is satisfied when input. In these cases, substantially the same function as when only the brake signal is turned on can be obtained.

  The engine control means A4 selectively takes in the engine operation information and the start standby rotation speed NADn or the low idle rotation speed NADL, which is the idle rotation speed NADA, and sets the engine rotation speed Ne in the normal operation range from the operation information. An ETV driver, each of which has a throttle opening θs, a fuel injection amount Tinj (see FIG. 5), and an ignition timing θp (see FIG. 5), in order to perform corresponding throttle valve control, injection amount control, and ignition timing control. 321, drive control is performed via an ignition driver 37 and a fuel injection driver 151.

  Here, the throttle valve driving unit a1 obtains the normal valve opening Pc or the idle opening Pc0 corresponding to the accelerator pedal opening θa, the vehicle speed Vc, the coolant water temperature wt, the atmospheric temperature Ta, and the like. Thus, each valve opening output corresponding to the calculated normal or idling opening Pc0 is output to the ETV driver 321 of the ETV 14 to control the intake air amount. In particular, as shown in FIG. 4, when the low idle speed NADL is achieved, the opening degree is corrected to the low idle time opening degree Pc1 after the second waiting time T2 described later, and the starting standby rotational speed NADn described later is obtained. When achieving this increase, the opening is corrected to the start standby opening Pc2. The throttle valve drive unit a1 corrects and controls the throttle valve opening based on the deviation between the actual value of the engine speed and the target speed so that the engine speed becomes the target speed. Accordingly, the throttle valve opening is corrected to increase or decrease with respect to the above-described opening Pc0, Pc1.

  The fuel amount control unit a2 obtains a basic fuel injection amount Tb corresponding to the engine speed Ne, the throttle opening θs, and the intake air amount Qa in a steady state, and a correction value TA such as the target air-fuel ratio A / F, the water temperature wt, etc. The fuel injection amount Tinj (= Tb + TA / F + Twt) is derived by adding / F and Twt. Then, an output signal D1 corresponding to the calculated fuel injection amount Tinj is output to the fuel injection driver 151, and the fuel injection valve 15 is driven to control the fuel injection amount.

  The ignition timing control unit a3 calculates the ignition timing IGT from the basic ignition timing IGTb corresponding to the throttle opening θs, the engine speed, and the like, and the retardation correction value ΔIG corresponding to the operating state in a steady state. After that, the output signal Dig calculated and corresponding to the ignition timing IGT is output to the ignition driver 37 and the igniter 36, and the ignition plug is driven to output, and ignition timing control as described later is performed particularly during idle operation. .

Here, the engine control means A4 has a low idling engine speed NADL (NADn−dN) in which the idling engine speed NADA becomes lower than the start standby engine speed NADn by a predetermined decrease amount dN when the conditions for allowing the engine speed reduction to be satisfied are satisfied in the idling region. Control to correct.
In particular, when the condition for permitting the reduction in rotation is released, the low idle speed NADL is raised toward a transition speed (NADn-dα) that is a predetermined reduction dα lower than the start standby speed NADn and the ignition timing of the engine 1 is advanced. When the angle is corrected (symbol −δa in FIG. 5) and the idling engine speed NADA reaches the engine speed during transition (NADn−dα), the ignition timing of the engine is retarded (sign + δa in FIG. 5).

  As described above, when the idling engine speed NADa is increased toward the transient engine speed (NADn−dα), the ignition timing is corrected in the advance angle region e1, thereby ensuring the response to increase in rotation. Further, when the engine speed reaches the transitional speed (NADn−dN), the process proceeds to the retarded angle region e2, and the ignition timing is retarded to compensate for the decrease in output due to the retarded compensation by increasing the intake air amount. The amount can be increased well and the turbine speed can be kept at the start standby speed at an early stage.

  Next, when a signal indicating that the rotation reduction allowable condition is satisfied is input, the supercharger control means A5 switches the wastegate valve 29 to the open position, and when the rotation reduction allowable condition is canceled, the idle rotation speed NADA is calculated. When the starting standby rotational speed NADn is raised, the waste gate valve is controlled to be fully closed to enter a starting standby state in which supercharging response can be ensured. As described above, when the rotation reduction allowance condition is satisfied, the wastegate valve is fully opened, the internal EGR is reduced along with the reduction of the exhaust resistance, and the idling rotation can be stabilized. On the other hand, the wastegate valve is closed during start waiting that is not satisfied, and the time from the start of supercharging until the superchargeable rotation range is reached is shortened to ensure supercharging response.

Next, the operation of the idle rotation control device for the internal combustion engine of FIG. 1 will be described together with the operation characteristic diagram of FIG. 3 and the control function that the ECU 27 performs according to the main routine (not shown) and the flowcharts of FIGS.
The ECU 27 is a main routine (not shown), fetches each data, performs failure check processing of various control system mechanisms, etc., performs idle rotation control and supercharger control, and particularly interrupts at a predetermined crank angle in the middle thereof. By the processing, the low idle rotation region entering and leaving routines of FIGS. 6 and 7 are sequentially executed.

  Assume that steps s1 to s3 of the low idle rotation region entering routine of FIG. 6 are reached in the middle of the main routine (not shown). Here, it is determined whether or not the vehicle is stopped with Vc = 0, and it is determined whether or not the accelerator opening is fully closed (during idling) while the vehicle is stopped. If fully closed, the brake signal Bs is determined to be on. The process proceeds to step s4 at time t1) when the vehicle speed is zero (time t2 in FIG. 3), and if any of these three rotation reduction allowance conditions is not satisfied, the process proceeds to step s5.

In steps s5 to s7, a count value of a first waiting time T1 that is a predetermined value is set (cleared) in a timer A to be described later, and a count value of a second waiting time T2 (> T1) that is a predetermined value is set in the timer B. Set (clear), turn off (clear) the idle rotation reduction flag, and return to the main routine.
Assuming that the rotation reduction allowance condition is satisfied from step s3 described above (time t2 in FIG. 3), when step s4 is reached, here the first waiting time T1 by the timer A from time t2 when the rotation decrease allowance condition is satisfied is reached. The count of 1 is disclosed, and while the timer is not 0, 1 is subtracted.

In step s8, the process proceeds to step s9 unless the timer A = 0, and the idle rotation decrease flag is turned off (cleared) during the waiting time although the rotation decrease allowable condition is satisfied, and the process returns to the main routine. In step s8, when timer A = 0 is reached (time t3 in the figure), the process proceeds to step s10, where the waste gate valve 29 is opened to stabilize idle rotation by reducing exhaust resistance and internal EGR.
In step s11, the timer B starts counting, and in step s12, the second waiting time T2 (> T1), which is a predetermined value, is counted to prevent hunting due to an operation error. After counting at time t4, the process proceeds to step s13.

  In steps s13 to s16, the engine starts to decrease in rotation from the start standby rotation speed NADn to the low idle rotation speed NADL, reads the set value in which the rotation decrease rate corresponding to the water temperature is mapped in advance with the water temperature, and decreases the engine rotation speed along the same value The idle rotation reduction flag is turned on, and the operation in the low idle rotation region (the region E1 in FIG. 3), which is the idle rotation reduction mode, is maintained.

  As described above, in the idling engine speed control device for the internal combustion engine of FIG. 1, when the allowance for reducing the rotation is satisfied, the idle engine speed NADA is controlled to the low idle engine speed NADL that is lower by the predetermined decrease amount dN, so that the fuel consumption is reduced. By maintaining the start standby rotation speed NADn, which is a steady idle rotation speed, in the operating range where the rotation reduction allowance condition is not satisfied, the responsiveness when the rotation speed increases when the start command is entered is maintained. Accordingly, it is possible to suppress a decrease in the responsiveness of the increase in the rotational speed when the start command is entered when the low low idle rotational speed NADL is maintained.

  In particular, since the idling speed is corrected toward the low idling speed NADL after the first waiting time T1 has passed and the rotation has stabilized, the rotation reduction control fluctuates due to data variations and the like, and the idling speed varies. Can be prevented. Further, since the idle gate speed 29 is opened after the first waiting time T1 has elapsed and the rotation is stabilized, unnecessary opening / closing variation of the waste gate valve 29 due to data variation can be prevented. The exhaust resistance can be reduced by opening the waste gate valve 29, and the rotation can be stabilized by reducing the internal EGR.

In particular, here, when the first waiting time T1 elapses and the waste gate valve 29 is opened, the control is performed to the low idle rotation speed NADL after the second waiting time T2 elapses, so that the rotation is stabilized at the low idle rotation speed NADL. Can be reliably achieved.
Next, it is assumed that the ECU 27 reaches the low idle rotation region departure routine of FIG. 7 by interruption processing at a predetermined crank angle in the middle of a main routine (not shown).
In step a1 of the low idle rotation region departure routine, it is determined whether or not a start standby mode flag, which will be described later, is on, the process proceeds to step a8, which will be described later. Here, it is determined whether or not there is a current operating range in the idling speed reduction mode, that is, the low idling speed range (see symbol E1 in FIG. 3) that satisfies the rotation reduction allowance condition. The control at the time of starting and running is executed, and the process returns to the main routine.

  When step a2 is reached again and the current operation range is in the low idle rotation range E1 and the idle rotation reduction mode is Yes, the process proceeds to step a3, where it is determined that the idle rotation reduction flag is off. While there is a current operating range at E1, the process proceeds to step a5 to allow the control to continue in the low idle rotation range e1 and return to the main routine.

  Step a3 is reached again. Here, if the idle rotation reduction flag is OFF, that is, the time t5 in FIG. 3 is reached and the brake switch Bs is considered to be turned off, and if the rotation reduction allowance condition is not satisfied, the vehicle starts. It is determined that the standby area E2 has been reached, and the process proceeds to step a6. Here, it is determined whether or not the accelerator opening is fully closed, that is, if there is a will to start, the process proceeds to step a4 on the No side, the normal control, starting and running control is executed, and the main routine is executed. Return.

  Again, when the accelerator opening on the Yes side in step a6 continues to be fully closed, the process proceeds to step a7, where control to the start standby mode a7 is allowed. Further, when step a8 is reached, the ETV 13 is driven to increase the low idle speed NADL toward the start standby speed NADn.

  Next, at step a9, the system waits for the idle speed NADA, which is the engine speed Ne, to reach a transient speed (NADn-dα) lower than the start standby speed NADn by a predetermined reduction dα, and during this time, the process proceeds to step a13. Here, the ignition timing is corrected to advance (signs -δa in FIGS. 4 and 5), the responsiveness to increase the idle speed NADA is ensured, and the process returns to the main routine.

  The process again proceeds to step a9, and if it is determined that the transient rotational speed (NADn−dα) has been reached, the process proceeds to steps a10, 11, and 12. Here, on the premise that the control to the start standby opening degree of the ETV 13 is continued, in particular, the ignition timing of the engine is corrected to be retarded (sign + δa in FIGS. 4 and 5) and the intake air amount is increased. Further, the waste gate valve 29 is switched from open to closed.

  When the transient rotational speed (NADn−dN) is reached by the control of steps a10, 11, and 12, the ignition timing is retarded and the output decrease due to the retard correction is compensated by the increase of the intake air amount, thereby increasing the exhaust flow rate. Further, the wastegate valve 29 is closed. By these processes, the time from the start of starting until reaching the superchargeable rotation range is shortened to achieve the supercharging standby state in which the supercharging response is ensured, and the process returns to the main routine.

In this way, in the idling engine speed control device for the internal combustion engine of FIG. 1, when the condition for allowing the rotation reduction is released, the low idling engine speed is raised to the start standby engine speed, and the wastegate valve is closed to ensure supercharging response. Can keep the waiting state.
In particular, when the idling engine speed is raised to a transient engine speed that is a predetermined decrease dα lower than the start standby engine speed NADn, the ignition timing is corrected to advance to ensure the response of the increased rotation, and the transient engine speed (NADn− When dα) is reached, the ignition timing θp is retarded and the intake air amount is increased and the exhaust flow rate can be increased efficiently, thereby increasing the turbine speed early and improving the acceleration response. .

Furthermore, in this idle rotation control device for an internal combustion engine, in the start standby operation region E2 where the rotation reduction allowance condition is not satisfied, the idle rotation speed is held at the start standby rotation speed, and a standby state in which responsiveness at the start operation can be secured. Can hold.
Note that FIG. 3 discloses an operation pattern in which the vehicle returns to the low idle rotation region E1 again at the time point t6 in the start standby operation region E2, and the same operation is performed after the time point t4. An effect is obtained.

1 is an overall configuration diagram of an engine 1 having an idle rotation control device for an internal combustion engine as an embodiment of the present invention. FIG. 2 is a block diagram of a control system of the idle rotation control device of FIG. 1. It is a timing chart diagram explaining the operating characteristic of the idle rotation control apparatus of FIG. It is characteristic explanatory drawing at the time of idle rotation raising control in the idle rotation control device of FIG. FIG. 2 is a stroke explanatory diagram of an engine equipped with the idle rotation control device of FIG. 1. It is a flowchart of the low idle rotation area approach routine used with the idle rotation control apparatus of FIG. FIG. 3 is a flowchart of a low idle rotation region leaving routine used in the idle rotation control device of FIG. 1. FIG.

Explanation of symbols

1 Engine 9 Turbocharger 13 Throttle valve (ETV)
29 Wastegate valve 31 Accelerator opening sensor 321 ETV driver 41 Shift speed sensor 50 Vehicle speed sensor 60 Brake switch dN Decrease amount θa Accelerator opening wt Ambient temperature A1 Idle rotation speed setting means A2 Idle rotation speed correction value setting means A3 Low idle rotation Zone determination means A4 Engine control means A5 Supercharger control means Bs Brake signal E1 Low idle speed range E2 Start standby area NADa Idle speed NADn Start standby speed NADL Low idle speed T1 First wait time T2 Second wait time Vc Vehicle speed signal

Claims (5)

Idle speed setting means for setting the idle speed of the internal combustion engine;
A wastegate valve attached to a supercharger that is supercharged with the exhaust energy of the exhaust path of the internal combustion engine;
A vehicle speed sensor for detecting a vehicle speed of a vehicle equipped with the internal combustion engine;
An accelerator opening sensor for detecting the accelerator opening of the vehicle;
Stoppage maintenance state detection means for detecting that the vehicle is in a stoppage maintenance state;
When the vehicle speed is zero, the accelerator opening is fully closed, and the rotation reduction allowance condition that the vehicle is in the stopped state is satisfied, the wastegate valve is opened and the idle rotation speed is reduced by a predetermined reduction amount. A control device for controlling to a low low idle speed,
An idling rotation control device for an internal combustion engine, comprising: The idle rotation control device for an internal combustion engine according to claim 1,
The control device opens the waste gate valve after a predetermined waiting time when the rotation reduction allowance condition is satisfied, and controls the idle rotation speed to the low idle rotation speed. apparatus. The idle rotation control device for an internal combustion engine according to claim 1 or 2,
The control device controls the idling engine speed to the low idling engine speed after opening the waste gate valve when the rotation reduction allowance condition is satisfied. The idle rotation control device for an internal combustion engine according to claim 1, 2, or 3,
In the operating range in which the rotation reduction allowance condition is satisfied, the control device reduces the low idle rotation speed to the start standby rotation when the rotation decrease allowance condition is canceled under a condition other than the fully closed condition of the accelerator opening. An idle rotation control device for an internal combustion engine, wherein the waste gate valve is closed while the number is increased. The idle rotation control device for an internal combustion engine according to claim 4,
When the condition for permitting the rotation reduction is released, the control device raises the low idle rotation speed toward a transient rotation speed that is a predetermined amount lower than the start standby rotation speed, and corrects the ignition timing of the internal combustion engine. An idle rotation control device for an internal combustion engine, wherein when the idle rotation speed reaches the transient rotation speed, the ignition timing of the internal combustion engine is retarded and the intake air amount of the internal combustion engine is increased and corrected. .

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