JP5010545B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine, and more particularly to a fuel cut that stops fuel supply when the engine is decelerated.

  Patent Document 1 sets a fuel cut delay time according to the engine speed and the intake pressure when a condition for executing a fuel cut at the time of engine deceleration is satisfied, and the fuel cut delay time elapses from the time when the fuel cut execution condition is satisfied. A fuel injection control device that starts fuel cut later is disclosed. By delaying the start of fuel cut, fluctuations in engine output torque at the start of fuel cut are prevented.

  Patent Document 2 discloses a control device that performs ignition timing retardation correction during a period from when a fuel cut execution condition is satisfied to when fuel cut starts. By correcting the retard of the ignition timing in addition to the delay at the start of fuel cut, fluctuations in engine output torque at the start of fuel cut can be prevented more reliably.

JP 2002-322931 A Japanese Patent No. 3747521

  In the apparatus disclosed in Patent Document 1, since the fuel cut delay time is set when the fuel cut execution condition is satisfied, there is a possibility that the fuel cut delay time is set in a state where the engine load is not stabilized. . In such a case, the fuel cut delay time becomes inappropriate, and torque fluctuation may occur at the start of fuel cut.

  In the apparatus disclosed in Patent Document 2, the timing for starting the ignition timing retardation correction is changed according to the engine speed, but the retardation correction amount is set to increase by a predetermined amount per unit time. Settings are not made according to the operating conditions. Therefore, there is room for improvement in appropriately performing the ignition timing retardation correction.

  The present invention has been made in consideration of the above-described points, and more appropriately controls the start timing of the fuel cut, and fluctuations in the engine output torque at the start of the fuel cut without excessively delaying the start of the fuel cut. The first object of the present invention is to provide a control device for an internal combustion engine that can suppress the ignition, and furthermore, the ignition timing delay correction immediately before the start of the fuel cut is appropriately executed to advance the start timing of the fuel cut and the fuel cut It is a second object to provide a control device for an internal combustion engine that can reliably prevent fluctuations in engine output torque at the start.

In order to achieve the above object, an invention according to claim 1 is directed to a control device for an internal combustion engine comprising fuel cut means for executing fuel cut for stopping fuel supply to the engine when the internal combustion engine is decelerated. Load detecting means for detecting (PBA), load change calculating means for calculating the detected engine load change (DPB), and the load change from the time point (t1) when the predetermined deceleration state of the engine is detected. Time measuring means for measuring a convergence time (CFCDLY) until a convergence time point (t2) when (DPB) is equal to or less than a predetermined value (DPBTH), and until fuel cut is started from the convergence time point (t2) The fuel cut delay time (TFCDLY) of the engine load (PBAFC) at the convergence time (t2) and the convergence time (CFC) timed by the time measuring means And a fuel cut delay time setting means for setting, based on LY), fuel cut delay time setting unit sets the higher the convergence time (CFCDLY) increases the fuel cut delay time (TFCDLY) long, the The fuel cut means starts the fuel cut after the fuel cut delay time (TFCDLY) has elapsed from the convergence time (t2).

  According to a second aspect of the present invention, in the control device for an internal combustion engine according to the first aspect, the engine load (PBAFC) at the convergence time point (t2) and the convergence time (CFCDLY) timed by the time measuring means. The ignition timing correction amount setting means for setting the ignition timing retardation correction amount (IGFCDLR) of the engine, and the retardation correction amount (in the period from the convergence time (t2) to the start of the fuel cut). Ignition timing correction means for correcting the ignition timing by IGFCDLR).

According to a third aspect of the present invention, in the control device for an internal combustion engine according to the first aspect, a shift position parameter detection for detecting a shift position parameter (NGR) indicating a shift stage of a transmission of a vehicle driven by the engine. And the fuel cut delay time setting means sets the fuel cut delay time (TFCDLY) to be longer as the shift speed is lower in accordance with the shift position parameter (NGR).
According to a fourth aspect of the present invention, in the control device for an internal combustion engine according to the first aspect, the fuel cut delay time setting means increases the fuel load as the engine load (PBAFC) increases at the convergence time (t2). A long cut delay time (TFCDLY) is set.
According to a fifth aspect of the present invention, in the control device for an internal combustion engine according to the second aspect, the ignition timing correction amount setting means increases the retardation correction amount (IGFCDLR) as the convergence time (CFCDLY) increases. It is set to increase.
According to a sixth aspect of the present invention, in the control apparatus for an internal combustion engine according to the second or fifth aspect, the engine speed detecting means for detecting the engine speed (NE) and the retard correction amount (IGFCDLR). Limiting means to limit the retard amount to an amount equal to or less than the retard amount upper limit value (IGFCDLMT), and the restricting means decreases the retard amount upper limit value (IGFCDLMT) as the engine speed (NE) increases. Features.
A seventh aspect of the present invention is the internal combustion engine control apparatus according to the second or fifth aspect, further comprising a limiting unit that limits the retardation correction amount (IGFCDLR) to a retardation amount upper limit (IGFCDLMT) or less. The limiting means increases the retardation amount upper limit (IGFCDLMT) as the engine load (PBAFC) at the convergence time (t2) increases.
It said ignition timing correction amount setting means comprises a boost value calculating means to calculate in accordance with the increase value per predetermined time (DIGFCDLR) the convergence time (CFCDLY), time using the increase value (DIGFCDLR) and Turkey said gradually increasing the retard correction amount (IGFCDLR) with the desirable.

According to the first aspect of the present invention, the convergence time is measured from the time when the predetermined deceleration state of the engine is detected until the convergence time when the load change amount converges to a predetermined stable state having a predetermined value or less, and the load change amount is measured. fuel cut delay time from the convergence point to the start of fuel cut, Ru is set based on the engine load and timed convergence time in the convergence time of the load change amount. Specifically, the fuel cut delay time is set longer as the convergence time increases, and the fuel cut is started after the fuel cut delay time has elapsed from the convergence time. The convergence time until the load change amount reaches the predetermined stable state reflects the influence of the engine operating state immediately before the transition to the predetermined deceleration state, so the fuel cut delay time is set according to the convergence time and the engine load at the time of convergence. By setting and setting the fuel cut delay time longer as the convergence time increases , fluctuations in engine output torque at the start of fuel cut can be suppressed without excessively delaying the start of fuel cut.

According to the second aspect of the present invention, the retard correction amount of the ignition timing is set based on the engine load at the convergence point of the load change amount and the measured convergence time, and using this retard correction amount, In the period from when the load change amount converges to when the fuel cut is started, the ignition timing is retarded. As a result, it is possible to set the fuel cut delay time on the assumption that the ignition timing is retarded, so the fuel cut start time is shortened while shortening the fuel cut delay time compared to when the retard angle is not compensated. It is possible to reliably prevent fluctuations in the engine output torque at the time.
According to the third aspect of the present invention, the shift position parameter indicating the shift stage of the transmission is detected, and the fuel cut delay time is set longer as the shift stage becomes lower in accordance with the shift position parameter. According to this invention, the fuel cut delay time is set longer as the engine load at the time of convergence increases.
According to the fifth aspect of the invention, the retardation correction amount is set to increase as the convergence time increases.
According to the sixth aspect of the present invention, the retard correction amount is limited to be equal to or less than the retard amount upper limit value, and the retard amount upper limit value is controlled to decrease as the engine speed increases. According to the described invention, the retardation correction amount is limited to the retardation amount upper limit value or less, and the retardation amount upper limit value is controlled to increase as the engine load at the time of convergence increases.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing a configuration of an internal combustion engine and a control device thereof according to an embodiment of the present invention. An internal combustion engine (hereinafter simply referred to as “engine”) 1 has an intake pipe 2, and a throttle valve 3 is disposed in the middle of the intake pipe 2. The throttle valve 3 is provided with a throttle valve opening sensor 4 for detecting the opening TH of the throttle valve 3, and a detection signal thereof is supplied to an electronic control unit (hereinafter referred to as “ECU”) 5.

  A fuel injection valve 6 is provided for each cylinder slightly upstream of an intake valve (not shown). Each injection valve is connected to a fuel pump (not shown) and is electrically connected to the ECU 5 to receive a signal from the ECU 5. Thus, the valve opening time of the fuel injection valve 6 is controlled. Each cylinder of the engine 1 is provided with a spark plug 12, and an ignition signal is supplied to the spark plug 12 from the ECU 5.

  An intake pressure sensor 7 for detecting the intake pressure PBA is provided immediately downstream of the throttle valve 3, and an intake air temperature (TA) sensor 8 is attached downstream of the intake pressure sensor 7. A cooling water temperature sensor 9 that detects the cooling water temperature TW of the engine 1 is attached to the main body of the engine 1. Detection signals from these sensors 7 to 9 are supplied to the ECU 5.

  A crank angle position sensor 10 that detects a rotation angle of a crankshaft (not shown) of the engine 1 is connected to the ECU 5, and a signal corresponding to the rotation angle of the crankshaft is supplied to the ECU 5. The crank angle position sensor 10 is a cylinder discrimination sensor that outputs a pulse (hereinafter referred to as “CYL pulse”) at a predetermined crank angle position of a specific cylinder of the engine 1, and relates to a top dead center (TDC) at the start of the intake stroke of each cylinder. A TDC sensor that outputs a TDC pulse at a crank angle position before a predetermined crank angle (every crank angle of 180 degrees in a four-cylinder engine), and a CRK that generates a CRK pulse at a constant crank angle period shorter than the TDC pulse (for example, a period of 30 degrees). It consists of sensors, and a CYL pulse, a TDC pulse and a CRK pulse are supplied to the ECU 5. These signal pulses are used for various timing controls such as fuel injection timing and ignition timing, and detection of engine speed (engine speed) NE.

  The ECU 5 is connected to a shift position sensor 13 for detecting the shift position of the transmission of the vehicle driven by the engine 1, and a shift position parameter NGR indicating the shift position (for example, “1st to 5th speeds” Is set to an integer value between “1” and “5”).

  The ECU 5 shapes input signal waveforms from various sensors, corrects the voltage level to a predetermined level, converts an analog signal value into a digital signal value, etc., and a central processing circuit (hereinafter referred to as “CPU”). A storage circuit that stores various calculation programs executed by the CPU, calculation results, and the like, an output circuit that supplies a drive signal to the fuel injection valve 6, and the like. The ECU 5 controls the valve opening time of the fuel injection valve 6 and the ignition timing of the spark plug 12 based on the detection signal of the sensor described above.

  FIG. 2 is a flowchart of a process for controlling the fuel cut start timing when performing a fuel cut to cut off the fuel supply during operation of the engine 1. This process is executed every predetermined time by the CPU of the ECU 5.

  In step S11, the CFCDLY calculation process shown in FIG. 3 is executed to calculate the convergence time parameter CFCDLY. The convergence time parameter CFCDLY is from the time when the throttle valve 3 is fully closed to the time of convergence when the intake pressure PBA change amount DPB converges to a predetermined stable state where the threshold value PBTH (for example, 5.3 kPa (40 mmHg) or less). It is a parameter proportional to the elapsed time.

  In step S31 of FIG. 3, it is determined whether or not the deceleration flag FTHDEC is “1”. The deceleration flag FTHDEC is set to “1” when the throttle valve 3 is fully closed. If the answer to step S31 is negative (NO), the convergence time parameter CFCDLY is set to “0”, and the stabilization flag FFCREADY is set to “0” (step S32).

If FTHDEC = 1 in step S31 and the throttle valve 3 is fully closed, the intake pressure change amount DPB is calculated by the following equation (1). “K” in the expression is a discretization time discretized in the execution cycle of this process. That is, the intake pressure change amount DPB is calculated as the absolute value of the difference between the current value PBA (k) and the previous value PBA (k-1) of the intake pressure PBA.
DPB = | PBA (k) −PBA (k−1) | (1)

  In step S34, it is determined whether or not the intake pressure change amount DPB is less than or equal to a predetermined threshold value DPBTH (is in a predetermined stable state). Initially, the answer to step S36 is negative (NO), and the process immediately proceeds to step S36 to determine whether or not the stabilization flag FFCREADY is “1”. Initially, this answer is negative (NO), so the convergence time parameter CFCDLY is incremented by “1” (step S37), and this process is terminated.

  When the intake pressure change amount DPB converges to a predetermined stable state that is equal to or less than the predetermined threshold value DPBTH, the stabilization flag FFCREADY is set to “1” (step S35). As a result, the answer to step S36 becomes affirmative (YES), and the increment of the convergence time parameter CFCDLY is terminated. Therefore, the convergence time parameter CFCDLY indicates the elapsed time from the time when the throttle valve 3 is fully closed to the convergence time when the intake pressure change amount DPB converges below the predetermined threshold value PBTH.

  Returning to FIG. 2, in step S12, it is determined whether or not the stabilization flag FFCREADY is “1”. While this answer is negative (NO), this processing is immediately terminated. When the stabilization flag FFCREADY is set to “1”, the process proceeds to step S13, and whether or not the timer set flag FTMSET is “1”. Is determined. Initially, this answer is negative (NO), the process proceeds to step S14, and the intake pressure PBA at that time is stored as the stabilized intake pressure PBAFC.

  In step S15, the TMPBFCDLY map shown in FIG. 4A is searched according to the convergence time parameter CFCDLY and the shift position parameter NGR, and the delay time basic value TMPBFCDLY is calculated. The TMPBFCDLY map is set so that the basic delay time value TMPBFCDLY increases as the convergence time parameter CFCDLY increases and as the shift position parameter NGR decreases. However, when the shift position parameter NGR is 3 to 5 (when the third speed to the fifth speed are selected), the delay time basic value TMPBFFDLY is set to substantially the same value. The predetermined value CFD1 in FIG. 4A is set to a value corresponding to 0.5 seconds, for example, and the predetermined delay time TMPFD1 is set to 0.5 seconds, for example.

  The setting of the TMPBFCDLY map shown in FIG. 4A is based on the following reason. The lower the gear position (the smaller the gear position parameter NGR), the greater the torque change at the start of fuel cut. In order to suppress the torque change, the smaller the gear position parameter NGR, the longer the delay time basic. The value TMPBFCDLY is set to increase. Further, the longer the time required for the stabilization of the intake pressure PBA, the longer the time required for the engine output torque to stabilize. Therefore, as the convergence time parameter CFCDLY increases, the delay time basic value TMPBFCDLY becomes larger. It is set to increase.

  In step S16, a KPBFCDLY table shown in FIG. 4B is retrieved according to the stabilized intake pressure PBAFC, and a delay time correction coefficient KPBFCDLY is calculated. The KPBFCDLY table is set so that the delay time correction coefficient KPBFCDLY increases as the stabilized intake pressure PBAFC increases. The predetermined intake pressures PB1 and PB2 in FIG. 4B are set to, for example, 26.7 kPa (200 mmHg) and 60 kPa (450 mmHg), respectively.

  As the intake pressure PBA when the engine shifts to a stable state, that is, the stabilized intake pressure PBAFC increases, the time required to reduce the engine output torque becomes longer. Therefore, KPBFFDLY shown in FIG. The table is set so that the delay time correction coefficient KPBFCDLY increases as the stabilized intake pressure PBAFC increases.

In step S17, the fuel cut delay time TFCDLY is calculated by applying the delay time basic value TMPBFCDLY and the delay time correction coefficient KPBFCDLY calculated in steps S15 and S16 to the following equation (2).
TFCDLY = TMPBFCDLY × KPBFCDLY (2)

  In step S18, the downcount timer TMFCDLY is set to the fuel cut delay time TFCDLY and started. In step S19, the timer set flag FTMSET is set to “1”. Since the answer to step S13 is affirmative (YES) after executing step S19, the process immediately proceeds from step S13 to step S20.

  In step S20, it is determined whether or not the value of the timer TMFCDLY is “0”. Initially, this answer is negative (NO), so the fuel cut flag FDECFC is set to “0” (step S22). When the fuel cut delay time TFCDLY elapses and the value of the timer TMFCDLY becomes “0”, the fuel cut flag FDECFC is set to “1”. Thereby, fuel cut is started.

Next, the ignition timing control will be described. In the present embodiment, the ignition timing IGLOG indicated by the advance amount from the compression top dead center is calculated by the following equation (3). In equation (3), IGMAP is a basic ignition timing calculated according to the engine speed NE and the intake pressure PBA, and IGFDLLR is a fuel for correcting the ignition timing retard immediately before the start of fuel cut, which will be described in detail below. It is a cut retard correction term, and IGCR is a correction term other than the fuel cut retard correction term IGFDCLR.
IGLOG = IGMAP-IGFCDLR + IGCR (3)

  FIG. 5 is a flowchart of a process for calculating the fuel cut retardation correction term IGFDLLR. This process is executed every predetermined time by the CPU of the ECU 5.

In step S41, it is determined whether or not the stabilization flag FFCREADY is “1”. If the answer to step S41 is negative (NO), the process proceeds to step S43, and the subtraction term DIGFCDA is calculated according to the engine speed NE. To do. In step S44, the fuel cut retardation correction term IGFCDLR and the subtraction term DIGFCDA are applied to the following equation (4) to gradually decrease the fuel cut retardation correction term IGFCDLR.
IGFCDLR = IGFCDLR-DIGFCDA (4)

  In step S45, it is determined whether or not the fuel cut retardation correction term IGFDCLR has a negative value. If the answer is affirmative (YES), the fuel cut retardation correction term IGFDCLR is set to “0” ( Step S46).

  In steps S43 to S46, when the throttle valve 3 is opened without performing fuel cut after the stabilization flag FFCREADY becomes “1”, the fuel cut retard correction term IGFDCLR is gradually set to “0”. It is provided to perform the return control. Normally, the fuel cut retardation correction term IGFCDLR is “0”, so the fuel cut retardation correction term IGFCDLR is maintained at “0” until the stabilization flag FFCREADY becomes “1”.

  When the stabilization flag FFCREADY is set to “1”, the process proceeds from step S41 to step S51, and it is determined whether or not the fuel cut flag FDECFC is “1”. Since this answer is negative (NO) at first, the process proceeds to step S55, and the DIGFCDLR table shown in FIG. 6A is searched according to the convergence time parameter CFCDLY to calculate the addition term DIGFCDLR. The DIGFCDLR table is set so that the addition term DIGFCDLR increases as the convergence time parameter CFCDLY increases. The predetermined values DIFD1 and DIFD0 shown in FIG. 6A are set to, for example, “1.3 deg” and “0.8 deg”, respectively.

  The longer the time required for the intake pressure PBA to stabilize, the faster the engine output torque needs to be reduced. Therefore, the DIGFCDLR table is set so that the addition term DIGFCDLR increases as the convergence time parameter CFCDLY increases. Has been.

  In step S56, the IGFCDLMT map shown in FIG. 6B is retrieved according to the stabilized intake pressure PBAFC and the engine speed NE, and the retard amount upper limit value IGFCDLMT is calculated. NE1, NE, NE3, NE4, and NE5 in FIG. 6B correspond to 1000 rpm, 2000 rpm, 3000 rpm, 4000 rpm, and 5000 rpm, and the predetermined values IGFDL1 and IGFDL2 are set to, for example, “10 deg” and “20 deg”, respectively. The That is, the IGFCDLRL map is set so that the retard amount upper limit value IGFCDLMT increases as the stabilized intake pressure PBAFC increases, and the retard amount upper limit value IGFCDLMT decreases as the engine speed NE increases. Since the higher the stabilized intake pressure PBAFC, the higher the combustion stability, the IGFCDLMT map is set so that the retard amount upper limit value IGFCDLMT increases as the stabilized intake pressure PBAFC increases.

In step S57, the addition term DIGFCDLR is applied to the following equation (5) to increase the fuel cut retardation correction term IGFCDLR.
IGFCDLR = IGFCDLR + DIGFCDLR (5)

  In step S58, it is determined whether or not the fuel cut retardation correction term IGFCDLR is larger than the retardation amount upper limit value IGFCDLMT. If the answer is affirmative (YES), the fuel cut retardation correction term IGFCDLR is retarded. The amount upper limit value IGFCDLMT is set (step S59). If IGFCDLR ≦ IGFCDLMT in step S58, the process is immediately terminated.

  Thereafter, when the fuel cut flag FDECFC is set to “1”, the process proceeds from step S51 to step S60, the fuel cut retardation correction term IGFDCLR is set to “0”, and this process is terminated.

  FIG. 7 is a time chart for explaining the processing of FIGS. 2 and 3, and shows an example in which the throttle valve is fully closed at time t1. A solid line L1 and a thick broken line L2 shown in FIG. 7B correspond to an example in which a relatively high load operation was performed before time t1, and the solid line L1 is an auxiliary machine (for example, an air conditioner) for the engine 1. The broken line L2 corresponds to the case where the auxiliary machine load is applied. A thin broken line L3 corresponds to an example in which a relatively low load operation was performed before time t1. As shown in FIG. 7, the convergence time until the intake pressure PBA is stabilized varies depending on the engine operating state immediately before the throttle valve is closed (solid line L1: TSFC, broken line L2: TSFCa, broken line L3: TSFCb). .

  Therefore, by setting the fuel cut delay time TFCDLY according to the convergence time parameter CFCDLY, an appropriate setting according to the engine operating state (engine load) immediately before the throttle valve is closed and the application state of the auxiliary load is set. It can be carried out. As a result, the fuel cut delay time TFCDLY is not set unnecessarily long, torque fluctuation at the start of fuel cut can be prevented, and fuel consumption can be improved. Also, assuming that the ignition timing IGLOG is corrected by the fuel cut retardation correction term IGFDCLR, a TMPBFCDLY map (FIG. 4 (a)) is set, so that torque fluctuation does not occur at the start of fuel cut. Further, the fuel cut delay time TFCDLY can be further shortened.

  The stabilized intake pressure PBAFC reflects the application state of the auxiliary load as indicated by the solid line L1 and the broken line L2 in FIG. Therefore, the fuel cut delay time TFCDLY suitable for the application state of the auxiliary machine load is set by correcting the delay time basic value TMPBFCDLY using the delay time correction coefficient KPFCFDLY set according to the stabilized intake pressure PBAFC. It can be carried out.

  Note that the convergence time parameter CFCDLY shown in FIG. 7C shows a change corresponding to the solid line L1, and the same applies to FIGS. 7D and 7E. That is, the stabilization flag FFCREADY is set to “1” at time t2, and the fuel cut flag FDECFC is set to “1” at time t3.

  FIG. 8 is a time chart for explaining the processing of FIG. 5. As in FIG. 7, the throttle valve is fully closed at time t1, and the stabilization flag FFCREADY is set to “1” at time t2. At t3, the fuel cut flag FDECFC is set to “1”. At time t2, an addition term DIGFCDLR corresponding to the increasing speed of the fuel cut retardation correction term IGFCDLR is set according to the convergence time parameter CFCDLY (convergence time TSFC), and the stabilized intake pressure PBAFC, which is the intake pressure at time t2, and A retard correction amount upper limit value IGFCDLMT is set in accordance with the engine speed NE.

  Since the addition term DIGFCDLR is set to a larger value as the convergence time parameter CFCDLY becomes larger, the increase rate of the fuel cut retardation correction term IGFCDLR is increased (the broken line L12 has a larger value for the addition term DIGFCDLR than the example of the solid line L11). An example is shown in which the retardation correction amount upper limit value IGFCDLMT is set to a larger value). As a result, the fuel cut retardation correction term IGFCDLR is set to a value suitable for the engine operating state (engine load) and the application state of the auxiliary load immediately before the throttle valve is closed. Further, since the retard correction amount upper limit value IGFCDLMT is set in accordance with the stabilized intake pressure PBAFC and the engine speed NE, it is set to a value suitable for the application state of the auxiliary load and the engine speed NE. As a result, the engine output torque is appropriately reduced immediately before the start of the fuel cut operation, and the torque fluctuation at the start of the fuel cut operation can be reliably prevented.

In the present embodiment, the intake pressure sensor 7 corresponds to load detection means, the crank angle position sensor 10 corresponds to engine speed detection means, the shift position sensor 13 corresponds to shift position parameter detection means, and the ECU 5 performs fuel cut. means, load change amount calculating means, time counting means, the fuel cut delay time setting means, the ignition timing correction amount setting means, ignition timing correction means, the limiting means, and boost value calculating hand stage. Specifically, step S21 in FIG. 2 corresponds to the fuel cut means, step S33 in FIG. 3 corresponds to the load change amount calculating means, steps S31 and S34 to 37 correspond to the time measuring means, and the steps in FIG. Steps S14 to S18 correspond to fuel cut delay time setting means, steps S55 to S59 in FIG. 5 correspond to ignition timing correction amount setting means, step S55 corresponds to increase value calculation means, and steps S56 , S58, and S59. Corresponds to the limiting means, and the calculation of the ignition timing IGLOG according to the equation (3) corresponds to the ignition timing correcting means.

  The present invention is not limited to the embodiment described above, and various modifications can be made. For example, in the above-described embodiment, in the period from the time when the throttle valve is fully closed and the intake pressure PBA is stabilized (the time when the stabilization flag FFCREADY is set to “1”) to the time when the fuel cut operation starts. Although the ignition timing retardation correction is performed, the ignition timing retardation correction need not be performed. In that case, a TMPBFCDLY map (FIG. 4A) is set on the assumption that the ignition timing retardation correction is not performed.

  The present invention can also be applied to control of a marine vessel propulsion engine such as an outboard motor having a crankshaft as a vertical direction.

It is a figure which shows the structure of the internal combustion engine and its control apparatus concerning one Embodiment of this invention. It is a flowchart of the process which controls the start time of a fuel cut. It is a flowchart of the subroutine performed by the process of FIG. It is a figure which shows the map and table referred by the process of FIG. 5 is a flowchart of processing for calculating an ignition timing retardation correction amount (IGFCDLR). It is a figure which shows the table and map referred by the process of FIG. It is a time chart for demonstrating the process of FIG.2 and FIG.3. It is a time chart for demonstrating the process of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Intake pipe 3 Throttle valve 5 Electronic control unit (fuel cut means, load change amount calculation means, timing means, fuel cut delay time setting means, ignition timing correction amount setting means, ignition timing correction means, increase value calculation means , Limiting means)
6 Fuel injection valve 7 Intake pressure sensor (load detection means)
10 Crank angle position sensor (engine speed detection means)
12 spark plug 13 shift position sensor (shift position detecting means)

Claims (7)

In a control device for an internal combustion engine comprising fuel cut means for executing fuel cut for stopping fuel supply to the engine during deceleration of the internal combustion engine,
Load detecting means for detecting the load of the engine;
Load change amount calculating means for calculating the detected engine load change amount;
Clocking means for timing a convergence time from a point in time when the predetermined deceleration state of the engine is detected to a convergence point when the load change amount converges to a predetermined stable state that is less than or equal to a predetermined value;
A fuel cut delay time setting means for setting a fuel cut delay time from the convergence time until the start of fuel cut based on the engine load at the convergence time and the convergence time measured by the time measuring means,
The fuel cut delay time setting means sets the fuel cut delay time longer as the convergence time increases,
The control apparatus for an internal combustion engine, wherein the fuel cut means starts the fuel cut after the fuel cut delay time has elapsed from the convergence time. Ignition timing correction amount setting means for setting a retard correction amount of the ignition timing of the engine based on the engine load at the convergence time and the convergence time measured by the time measuring means;
2. The control of the internal combustion engine according to claim 1, further comprising an ignition timing correction unit that corrects the ignition timing with the retardation correction amount during a period from the convergence time to the start of the fuel cut. apparatus.   Shift position parameter detecting means for detecting a shift position parameter indicating a shift stage of a transmission of a vehicle driven by the engine;
  2. The control device for an internal combustion engine according to claim 1, wherein the fuel cut delay time setting unit sets the fuel cut delay time to be longer as the gear position becomes lower in accordance with the shift position parameter.   2. The control apparatus for an internal combustion engine according to claim 1, wherein the fuel cut delay time setting means sets the fuel cut delay time longer as the engine load at the convergence time increases.   3. The control apparatus for an internal combustion engine according to claim 2, wherein the ignition timing correction amount setting means sets the retardation correction amount to increase as the convergence time increases.   Engine speed detecting means for detecting the engine speed;
  Limiting means for limiting the retardation correction amount to a retardation amount upper limit value or less,
  6. The control device for an internal combustion engine according to claim 2, wherein the limiting means decreases the retardation amount upper limit value as the engine speed increases.   Limiting means for limiting the retardation correction amount to a retardation amount upper limit value or less;
  6. The control apparatus for an internal combustion engine according to claim 2, wherein the limiting means increases the retardation amount upper limit value as the engine load at the convergence time increases.

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