JP3041089B2 - Internal combustion engine deceleration control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deceleration control method for an internal combustion engine, and more particularly to a method for enhancing an engine braking effect during deceleration.

[0002]

2. Description of the Related Art In recent years, in order to improve the controllability of an internal combustion engine, a throttle valve is driven by an actuator such as a stepping motor or the like, and the throttle valve is controlled in accordance with a stepping amount or stepping speed of an accelerator pedal and engine operating parameters. A technique has been proposed in which the means controls the actuator to control the opening of the throttle valve (for example, Japanese Patent Application Laid-Open No. 02-169838).

[0003]

However, in the above-described internal combustion engine of the actuator drive type, the throttle valve driving speed of the stepping motor as the actuator is a stepping force by mechanically connecting an accelerator pedal and a throttle valve which are generally used conventionally. For example, it takes about 1 second from the fully opened valve to the fully closed valve as compared with the case of driving. Further, it has been difficult to increase the driving speed of the stepping motor due to the control accuracy of the valve opening.

As described above, if it takes time from the full opening to the full closing of the throttle valve, the rise of the negative pressure in the intake pipe is delayed, and the engine brake is not effective at the time of deceleration of the engine (hereinafter referred to as "idle running state"). ") Is longer,
It is assumed that the driving feeling is not favorable.

The present invention has been made in view of the above circumstances, and relates to a deceleration control method for an internal combustion engine that can reduce idle running during deceleration and obtain a good driving feeling.

[0006]

In order to achieve the above object, the present invention provides a method for controlling the deceleration of an internal combustion engine having an intake valve whose opening period can be changed arbitrarily and an electrically operated throttle valve. When the deceleration state of the engine is detected, the opening period of the intake valve is set to be longer than a predetermined opening period, and deceleration control is performed to make the opening of the throttle valve smaller than the predetermined opening. An internal combustion engine wherein an opening period of the intake valve is made shorter than a second predetermined opening period smaller than the predetermined opening time until the opening of the throttle valve becomes smaller than the predetermined opening. To provide a deceleration control method.

In a deceleration control method for an internal combustion engine having an intake valve whose opening period can be arbitrarily changed and an electrically operated throttle valve, a deceleration state of the engine and a stop of fuel supply to the engine are provided. When the states are simultaneously detected, deceleration control is performed so that the opening period of the intake valve is longer than a predetermined opening period and the opening degree of the throttle valve is smaller than the predetermined opening degree. A deceleration control method for an internal combustion engine, wherein an opening period of the intake valve is made shorter than a second predetermined opening period smaller than the predetermined opening time until the opening of the intake valve becomes smaller than the predetermined opening degree. I will provide a.

[0008]

In the deceleration control method for an internal combustion engine according to the present invention, when the deceleration state of the engine is detected, the opening period of the intake valve is made longer than the predetermined opening period, and the opening of the throttle valve is set to the predetermined opening degree. Make it smaller. This creates an engine braking condition due to pumping loss. At this time, the opening period of the intake valve is set shorter than the predetermined opening period until the opening of the throttle valve becomes smaller than the predetermined opening. This prevents the intake air from flowing into the combustion chamber, and reduces the idling state during deceleration. In particular, by performing the deceleration control when the fuel supply to the engine is stopped, it is not necessary to control the fuel supply during the deceleration control, and the deceleration control can be performed simply and reliably.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram showing an example of the overall configuration of an internal combustion engine to which a method for controlling deceleration of an internal combustion engine according to the present invention is applied. In FIG. 1, the collecting part 1a of the intake pipe 1
Is provided with a throttle valve 2, and an actuator 3 composed of, for example, a stepping motor is connected to the throttle valve 2. The actuator 3 is connected to an electronic control unit (hereinafter referred to as “ECU”) 4 and
The throttle valve 2 is driven according to the control signal from U4. A throttle valve opening (θTH) sensor 5 is mechanically connected to the throttle valve 2, and a detection signal thereof is supplied to the ECU 4.

An air cleaner 3 is provided at an upstream end of the collecting portion 1a of the intake pipe 1. Further, a bypass pipe 6 for bypassing the throttle valve 2 is connected between the collecting section 1a of the intake pipe 1 and the branch section 1b on the downstream side thereof, and a bypass valve 7 composed of a linear solenoid or the like is provided in the middle of the bypass pipe 6. Are arranged. The opening and closing of the bypass valve 7 is controlled by a signal from the ECU 4.

A branch portion 1b of the intake pipe 1 has an intake air temperature (T
A) A sensor 8 and an intake pipe absolute pressure (PB) sensor 9 are mounted, and these detection signals are supplied to the ECU 4. Furthermore,
A vacuum tank 10 for accumulating a negative pressure in the intake pipe is connected to a branch portion 1b of the intake pipe 1 via a check valve 11. The negative pressure sensor 12 is a vacuum tank 10
The internal negative pressure is detected and a detection signal is supplied to the ECU 4. The negative pressure accumulated in the vacuum tank 10 is applied to the pipe 10
a supplies to each device of the engine that requires a negative pressure.
A fuel injection valve 13 is attached to the branch portion 1b of the intake pipe 1, and is urged to inject fuel for a valve opening time according to a control signal from the ECU 4.

An intake valve 15 is mounted on an intake port 24 between the intake pipe 1 and each cylinder 14 of the cylinder block of the engine, and is controlled by a control signal from the ECU 4 via a hydraulically driven valve unit 30 (FIG. 2) described later. Thus, the valve opening period (valve opening timing and / or valve closing timing) is controlled. On the other hand, the exhaust pipe 16
An exhaust valve 17 is attached to an exhaust port between the cylinder and each cylinder 14, and a valve opening period is controlled by a control signal from the ECU 4 via a hydraulically driven valve unit (not shown).

A (TW) sensor 18 is inserted into the water jacket on the peripheral wall of the cylinder 14 of the engine, and the detection signal is supplied to the ECU 4. Also, the engine speed (N
E) A sensor 19 is disposed to face the crankshaft of the engine, and a pulse signal (TDC) is provided at each predetermined crank angle of each cylinder.
Signal) and supplies it to the ECU 4.

The oil pressure (Toi1) sensor 20 detects the temperature of the hydraulic oil of the hydraulic drive unit 30 and outputs the detection signal as E.
Send to CU4.

An O ₂ sensor 21 is inserted into the exhaust pipe 16 to detect the oxygen concentration in the exhaust gas, and the detection signal is sent to the ECU.
4 Further, a three-way catalyst 15 for purifying exhaust gas is disposed downstream of the O ₂ sensor 21 in the exhaust pipe 16.

The ECU 4 further includes an accelerator opening sensor 6 for detecting an accelerator pedal depression amount (θACC) as a parameter indicating a driver's request for the engine.
0, an atmospheric pressure sensor 61 for detecting an atmospheric pressure (PA), and a vehicle speed sensor 62 for detecting a traveling speed (V) of a vehicle equipped with an engine are electrically connected. It is supplied to the ECU 4. The ECU 4 includes a central processing unit, a memory, a control signal output circuit, and the like (not shown).
The operation control of the hydraulic drive valve unit 30 and the like and the ignition timing control are performed based on detection signals from various sensors, and the valve opening time of the fuel injection valve 13 is controlled.

FIG. 12 is a sectional view of the hydraulically driven valve unit 30. The unit 30 is mounted on the cylinder head 14a of each cylinder 14 of the engine. The cylinder head 14a has an intake valve port 23 which is open at the top of the combustion chamber 14b (FIG. 1) of the engine and the other of which is connected to an intake port 24.
Is provided. The intake valve 15 is arranged so as to be movably guided in the cylinder head 14a in the vertical direction in the figure to open and close the intake valve port 23. A valve spring 26 is contracted between the flange 25 of the intake valve 15 and the cylinder head 14a. The valve spring 26 biases the intake valve 15 upward (to close the valve) in the figure. You.

On the other hand, on the left side of the intake valve 15 in FIG.
7 is rotatably disposed. The camshaft 28 is connected to a crankshaft (not shown) via a timing belt (not shown). Camshaft 2
A hydraulic drive valve unit 30 is interposed between the intake valve 15 and the cam 27 that is formed integrally with the intake valve 8.

The hydraulic drive valve unit 30 includes a hydraulic drive mechanism 30A for opening and closing the intake valve 15 by pressing the intake valve 15 downward against the valve spring 26 in accordance with the profile of the cam 27, and a pressing force of the hydraulic drive mechanism 30A. During the valve opening operation,
Thus, the hydraulic pressure release mechanism 30B closes the intake valve 15 regardless of the cam profile.

The hydraulic drive mechanism 30A includes a cylinder head 2
A first cylinder body 33 fixed to a block 32 formed integrally with the first cylinder body 1, and a lower end (front end) abutting against an upper end (rear end) of the intake valve 15 and a cylinder hole 33 a of the first cylinder body 33. A valve-side piston (valve drive piston) 34 slidably fitted in the first cylinder body 33 and the valve-side piston 34;
A lifter 35 slidingly in contact with the cam 27, and a lower end contacting the lifter 35 to be slidably fitted to a lower portion of the second cylinder body 36. The main constituent elements are a cam-side piston 37, a hydraulic pressure generating chamber 39 defined by the second cylinder body 36 and the cam-side piston 37, and an oil passage 40 communicating the hydraulic pressure generating chamber 39 and the working hydraulic chamber 38. When the hydraulic pressure in the working hydraulic chamber 38 is equal to or higher than a predetermined value, the intake valve 1
5 is opened and closed.

The block 32 includes a flange 25 of the intake valve 15.
The lift sensor 62 is disposed at a position facing the.
The lift sensor 62 is electrically connected to the ECU 4, detects a lift amount of the intake valve 15, and outputs a detection signal of the lift amount to the ECU 4.
Supply to CU4.

On the other hand, the hydraulic pressure release mechanism 30B
0, a refueling gallery 42, an oil passage 41, a spill valve 45 interposed in the oil passage 41, a feed valve 43 and a check valve 44 disposed in the oil passage 41, and these valves. The accumulator 46 for holding the release hydraulic pressure in the accumulator circuit 41a defined by the spill valve 45 and the spill valve 45 is a main component. Spill valve 4
The solenoid 45a of No. 5 is connected to the ECU 4 and is excited and demagnetized by its control signal. The refueling gallery 42 is provided for supplying a hydraulic pressure to a hydraulic drive valve unit provided for each cylinder, and is connected to an oil pump 47. The oil pump 47 supplies hydraulic oil in an auxiliary oil pan 48 provided in the cylinder head 21 to the oil supply gallery 42 as oil pressure within a predetermined range. The hydraulic oil supplied to the oil supply gallery 42 may be supplied by an oil pump from an oil pan provided below the crankcase (not shown).

The accumulator 46 includes the hydraulic release mechanism 30
A cylinder hole 461 formed in the block 32 and provided in the accumulator circuit 41a to accumulate the hydraulic pressure and the drain oil released by the spill valve 45 of B, and an air hole 4
A cap 463, a piston 464 slidably fitted in the cylinder hole 461, and a cap 463.
And a spring 465 contracted between the piston and the piston 464.

The details of the configuration of the hydraulic drive mechanism 30A and the hydraulic release mechanism 30B are described in JP-A-01-91352.

The hydraulic drive mechanism 30 constructed as described above
The operation of A and the hydraulic release mechanism 30B will be described below.

When the solenoid 45a of the spill valve 45 is energized by a control signal from the ECU 4, the spill valve 45 is closed and the hydraulic pressure generating chamber 39, the oil passage 40 and the working hydraulic chamber 38 of the hydraulic drive mechanism 30A are closed. Is maintained at a high pressure equal to or higher than a predetermined value, and the opening and closing drive of the intake valve 15 is performed according to the profile of the cam 27. Therefore, the valve operating characteristics in this case (the relationship between the crank angle and the valve lift)
Is as shown by the solid line in FIG.

On the other hand, when the intake valve 15 is opened, the solenoid 45a of the spill valve 45 operates according to a control signal from the ECU 4.
Is demagnetized, the spill valve 45 is opened, the hydraulic pressure in the hydraulic pressure generating chamber 39, the oil passage 40, and the working hydraulic chamber 38 of the hydraulic drive mechanism 30A decreases, and the intake valve is regardless of the profile of the cam 27. 15 starts the valve closing operation. At this time,
The closing speed of the intake valve 15 is relaxed during the closing operation by the hydraulic oil return amount limiting mechanism provided on the valve-side piston 34, and the intake valve 15 is gently seated on the valve seat 21a. The valve operating characteristic in this case is as shown by a broken line in FIG. That is, in FIG.
When a is demagnetized, a little after θOFF (θ = θS
T) The intake valve 15 starts the valve closing operation, and the valve closing is completed at θ = θIC.

As described above, the spill valve 45 is opened and closed by the control signal from the ECU 4, and the operation of the hydraulic drive mechanism 30A is invalidated when the spill valve 45 is opened.
The valve closing start timing (valve closing timing) of the intake valve 15 and, accordingly, the valve opening period can be arbitrarily set. As a result, the intake air amount of each cylinder can be controlled by the control signal of the ECU 2.

In this embodiment, the same hydraulic drive valve unit (not shown) is provided on the exhaust valve side as on the intake valve side, but the exhaust valve side normally closes at a constant timing according to the cam profile. Or a variable valve timing mechanism capable of setting a plurality of opening / closing timings.

Next, an embodiment of a deceleration control method for an internal combustion engine according to the present invention will be described with reference to FIGS.

FIGS. 4 and 5 are flowcharts showing the embodiment. First, the engine speed NE and the accelerator opening θA
CC, throttle valve opening θTH, engine coolant temperature T
W, hydraulic oil temperature Toi1 of hydraulic drive valve unit 30, negative pressure in intake pipe (hereinafter referred to as "intake pressure") PB, and vehicle speed V
Are read from the sensors 19, 60, 18, 20, 9, and 62 of FIG. 1 respectively (step S1).

Next, it is detected whether or not the engine is in a decelerating state (step S2). The detection of the deceleration state is performed using the tables shown in FIGS. 6 to 8,
DR1, DR3, and DR5 are areas determined to be in a deceleration state,
DR2, DR4, and DR6 are areas that are not determined to be in the deceleration state. In FIG. 6, the horizontal axis represents the accelerator opening θACC,
The vertical axis indicates the engine speed NE. As shown in the figure,
Basically, if NE is high and θACC is small, it is determined that the vehicle is decelerating. If NE is lower than a predetermined value or θACC is larger than a predetermined value, it is not determined that the vehicle is decelerating. FIG.
The horizontal axis represents the accelerator opening θACC, and the vertical axis represents the vehicle speed V.
Is shown. As shown in the figure, basically, V is large and θA
If CC is smaller, it is determined that the vehicle is in a deceleration state, and if θACC is smaller than a predetermined value, it is determined that the vehicle is in a deceleration state regardless of V. Further, in FIG. 8, the horizontal axis indicates the accelerator opening speed ΔθACC, and the vertical axis indicates the engine speed NE. As shown in FIG.
Is within a predetermined range and ΔθACC is within a predetermined range of a large negative value, it is determined that the vehicle is in a deceleration state. The state in which ΔθACC is within a predetermined range of a large negative value is a case where the accelerator pedal is suddenly returned, and in such a state, the driver requests deceleration. ΔθACC is, for example, θAC for each output signal (crank angle signal) pulse of the engine speed sensor 19.
The C value may be read and determined from the difference in the θACC values between the time when the pulse was generated several times before and the time when the current pulse was generated, or may be determined from the difference in the θACC values read for each pulse of a fixed cycle. This deceleration determination is for determining that the region DR2 'in FIG. 6 is also in a deceleration state when ΔθACC is a large negative value, and in the region DR2' in FIG. 6, the accelerator opening θACC.
If does not fall below the predetermined value, the deceleration process is not performed.
By using the determination in FIG. 8, there is an effect that the deceleration state is determined early even if θACC is equal to or more than the predetermined value. As a method of determining whether or not the vehicle is in the deceleration state, each sensor value is determined in the
When either one or both of R1 and DR3 are indicated, each sensor value indicates one of the regions DR1 and DR3 or indicates DR5, or
There is a method of determining that the state where each sensor value indicates both the regions DR1 and DR3 or the region DR5 is a deceleration state.

Returning to FIGS. 4 and 5, when it is determined in step S2 that the vehicle is in a deceleration state, the engine is cut off (F / F).
C) It is determined whether or not it is in the area (step S3). This determination is made using FIG. In FIG. 9, the horizontal axis indicates the engine cooling water temperature TW or the oil temperature Toi1, the vertical axis indicates the engine speed NE, DR7 is a region that is determined as an F / C region, and DR8 is a region that is not determined as an F / C region. is there. As shown in the drawing, as the TW or Toi1 is higher, that is, as the engine temperature is higher, the lower NE is determined as the F / C region.

If it is determined in step S3 that the area is the F / C area, a fuel cut is executed (step S4). As described above, by executing the fuel cut, it is not necessary to control the fuel during the deceleration control, and the valve opening time of the intake valve 15 described later can be controlled by considering only the engine braking effect (FIG. 13). Engine deceleration control can be performed simply and reliably.

Next, the throttle valve opening command value THCMD
Is determined and output to the actuator 3 of FIG. 1 as the target throttle valve opening value THTRG during deceleration (step S
5, S6). The target value THTRG is determined according to the engine speed NE as shown in FIG. 10, but its characteristic curve differs depending on the type of the engine and the like as shown by the solid line, broken line and dashed line in FIG. The target value THTRG is θT when NE = NE1 when the throttle valve opening θTH is set to THTRG in a state where the engine speed during deceleration NE> NE1.
If H = THTRG1, the value is set to such a value that an engine brake state can be created if the closing timing of the intake valve is set to a target value OFF MAP described later.

Next, the throttle valve opening .theta.TH is equal to the target throttle valve opening value THTRG at the time of deceleration + the predetermined opening value .DELTA.THT.
It is determined whether or not it is equal to or less than RG (for example, 0.5 degrees) (step S7). If θTH> THTRG + ΔTHTRG, the current target closing timing (valve closing time) of the intake valve 15 is calculated from ΔθTH = θTH−THTRG. θOFFTMG (n)
(Steps S8, S9). This θOFFTM
The G (n) search is performed using the OFFTR vs. ΔθTH table in FIG. 11 to find the OFFTR corresponding to ΔθTH,
This OFFTR is defined as θOFFTMG (n). FIG.
As shown in the figure, if the value of ΔθTH is small, θTH is TH
Since it is close to TRG, the intake valve can be slightly opened to bring the engine into a brake state. OFFTRO in FIG. 11 is Δ
This is the opening period (predetermined valve opening period) of the intake valve 15 when θTH = 0.

Next, the flag FLG is set to "0" (step S10). The flag FLG is set in step S described later.
At 13, the closing period of the intake valve 15 is equal to the target closing timing θOFFT.
When set to MG, it is set to “1” (step S
14). Next, an output routine of the target valve closing timing θOFFTMG is executed (step S11).

On the other hand, if it is determined in steps S2 and S3 that the engine is not in the deceleration state, or if it is determined that the engine is in the deceleration state but is not in the F / C region, the flag FLG is set.
Is set to "0" (step S10), and an output routine is executed (step 11). In this case, the target valve closing timing θOFF TMG of the intake valve 15 is set to θO during normal operation (not shown).
Determined by the FFTMG determination routine. In the output routine, the θOFFTMG value is further corrected according to the engine speed NE, the oil temperature Toil, and the like, converted into a spill valve 45 control signal, and output.

In step S7, θTH ≦ THTRG
When + ΔTHTRG has been reached, the process proceeds to step S12, and it is determined whether or not the flag FLG is “0”. Initially, FLG is “0”, so the current target valve closing timing θOFFTMG (n) of the intake valve 15 is set to OFFMA.
P (Step S13), the flag FLG is set to "1" (Step S14), and the routine goes to Step S11. The value of OFFMAP is obtained from the table of FIG. As shown in the figure, the value of OFFMAP is a value corresponding to the value of the engine speed NE, and becomes a fully opened value at a predetermined speed or less. Note that the reason why the intake valve 15 is not fully opened when the NE is high is that if the engine is fully opened, the intake pressure PB becomes too large and the effect of the engine brake becomes sharp, so that the driving feeling may be reduced.

If the flag FLG is set to "1" instead of "0" in step S12, the process proceeds to step S15, where the value of the intake pressure PB (negative pressure) and the target pressure PAC during deceleration are set.
It is determined whether the absolute value of the difference from the OFF value | PB-PACOFF | is equal to or less than the dead zone α. Target pressure PACOFF
Is provided to prevent the engine oil from rising into the engine combustion chamber due to the generation of an excessive negative pressure and increasing the blow-by amount, and is provided in step S15.
Steps S21 to S21 are a processing flow for bringing the value of the intake pressure PB closer to the value of the target pressure PACOFF.

When | PB-PACOFF |> α,
Next, it is determined whether or not PB-PACOFF> 0 (step S16), and it is not PB-PACOFF> 0, that is, PB-P
If ACOFF ≦ 0, the value of the intake pressure PB is smaller than the value of the deceleration target pressure PACOFF.
G (n) is the previous intake valve target valve closing timing θOFFTMG
To make it slower than (n-1), θOFFTMG (n) =
θOFFTMG (n-1) -β (PB-PACOFF)
(Step S17). The value of the correction coefficient β is obtained from the table of FIG. As shown in the figure, the value of β is NE
The higher is the smaller. This is because the higher the NE, the greater the pumping action of the engine. Therefore, the higher the NE, the more the intake valve closing timing for controlling the value of PB should be corrected in the earlier direction, that is, the shorter the valve opening period. This is because, as NE is lower, it is necessary to correct the intake valve closing timing in a later direction, that is, in a longer opening period.

Next, it is determined whether or not the value of .theta.OFFTMG (n) is equal to or less than the limit value (step S18). If the value is less than the limit value, the process proceeds to step S14 while keeping the value of .theta.OFFTMG (n) as it is. Set FLG to “1”. If the value of θOFFTMG (n) exceeds the limit value, the process proceeds to step S14 using the value of θOFFTRMG (n) as the limit value (step S19). This prevents a sudden change in the valve opening period of the intake valve.

In step S15, | PB-PACOFF |
If ≤α, the value of the intake pressure PB is an appropriate value, and the value of the current intake valve target opening angle θOFFTMG (n) is set to be the same as the previous valve opening angle θOFFTMG (n-1) ( Step S20), the value of the intake pressure PB is maintained at the previous value.

In step S16, PB-PACOFF> 0
In this case, since the value (negative pressure) of the intake pressure PB is large, the bypass valve 7 in FIG. 1 is opened (step S21), and the intake pressure PB
Decrease the value of B. This is because the bypass valve 7 has better controllability such as response than the throttle valve 2, but, of course, the opening of the throttle valve 2 may be controlled in the opening direction by a predetermined amount instead of the bypass valve 7. Alternatively, both the bypass valve 7 and the throttle valve 2 may be controlled.

In the above embodiment, steps S8, S
9, the target opening angle of the intake valve θOFFTMG from ΔθTH
Although (n) is obtained, θOFFTMG (n) may not be obtained from ΔθTH and may be a value in the fully closed state of the intake valve. That is, as shown by, for example, the characteristic curve of the solid line in FIG. 10, the engine speed NE decreases to NE1 (for example, 2000 rpm),
Throttle valve opening θTH is THTRG1 = THTRG +
Until ΔTHTRG, the intake valve 15 may be fully closed, and when θTH ≦ THTRG1, the closing timing of the intake valve 15 may be controlled in step S12 and subsequent steps.

[0047]

As described above, the present invention relates to a deceleration control method for an internal combustion engine having an intake valve whose opening period can be arbitrarily changed and an electrically operated throttle valve. Is detected, the opening period of the intake valve is made longer than a predetermined opening period, and deceleration control is performed to make the opening of the throttle valve smaller than the predetermined opening. In the deceleration control, the opening of the throttle valve is performed. By setting the opening period of the intake valve to be smaller than the second predetermined opening period that is smaller than the predetermined opening time until the degree becomes smaller than the predetermined opening degree, the throttle valve opening degree becomes equal to or less than the predetermined opening degree. Until the intake valve can be fully closed or controlled to a predetermined valve opening time in the vicinity thereof, it is possible to eliminate the influence of the throttle valve drive delay and reduce the idling state during deceleration. It can be made a driving feeling good.

Further, in a deceleration control method for an internal combustion engine having an intake valve whose opening period can be changed arbitrarily and an electrically operated throttle valve, a deceleration state of the engine and a stop of fuel supply to the engine are provided. When the states are simultaneously detected, deceleration control is performed so that the opening period of the intake valve is longer than a predetermined opening period and the opening degree of the throttle valve is smaller than the predetermined opening degree. By setting the valve opening period of the intake valve to be smaller than the second predetermined valve opening period smaller than the predetermined valve opening time until the opening degree of the valve becomes smaller than the predetermined opening degree, the same effect as described above can be obtained. Since it is not necessary to control the fuel during the deceleration control, the deceleration control can be performed simply and reliably.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an overall configuration of an internal combustion engine to which a deceleration control method of the present invention is applied.

FIG. 2 is a sectional view of a hydraulic drive valve unit.

FIG. 3 is a characteristic diagram showing operation characteristics of an intake valve.

FIG. 4 is a flowchart showing an embodiment of the present invention.

FIG. 5 is a flowchart showing an embodiment of the present invention.

FIG. 6 is a table diagram for determining a deceleration area.

FIG. 7 is a table for determining a deceleration area.

FIG. 8 is a table for determining a deceleration area.

FIG. 9 is a table for determining a fuel cut area.

FIG. 10 is a graph showing the relationship between the target throttle valve opening THTRG during deceleration and the engine speed NE.

FIG. 11: intake valve target valve opening angle θOFF TMG = OFF
7 is a graph showing a relationship between TR and a difference ΔθTH between a throttle valve opening and a target throttle valve opening during deceleration THTRG during deceleration.

FIG. 12 shows a target opening angle of the intake valve θOFF TMG = OFF
It is a graph which shows the relationship between MAP and engine speed NE.

FIG. 13 is a graph showing a relationship between a correction coefficient β and an engine speed NE.

[Explanation of symbols]

 2 Throttle valve 4 ECU 15 Intake valve

Continuation of the front page (51) Int.Cl. ⁷ identification code FI F02D 41/12 320 F02D 41/12 320 330 330 330Z (56) References JP-A-4-191448 (JP, A) JP-A-4-191414 ( JP, A) JP-A-4-143432 (JP, A) JP-A-3-189325 (JP, A) JP-A-55-87835 (JP, A) JP-A-4-292551 (JP, A) JP Hei 4-203247 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02D 13/02 F02D 9/02 F02D 13/04 F02D 41/12

Claims (6)

(57) [Claims] 1. An intake valve whose opening period can be arbitrarily changed;
A deceleration control method for an internal combustion engine having an electrically operated throttle valve, wherein when the deceleration state of the engine is detected, the opening period of the intake valve is made longer than a predetermined valve opening period, and the opening of the throttle valve is opened. Deceleration control to make the degree smaller than the predetermined opening degree, and in the deceleration control,
An internal combustion engine according to claim 1, wherein an opening period of said intake valve is smaller than a second predetermined opening period smaller than said predetermined opening time until the opening of said throttle valve becomes smaller than said predetermined opening. Deceleration control method. 2. An intake valve whose opening period can be arbitrarily changed;
A deceleration control method for an internal combustion engine having an electrically operated throttle valve, wherein when the deceleration state of the engine and the stop state of fuel supply to the engine are detected simultaneously, the opening period of the intake valve is opened by a predetermined amount. The deceleration control is performed to make the opening of the throttle valve smaller than a predetermined opening while making the opening of the throttle valve smaller than the predetermined opening. A deceleration control method for an internal combustion engine, wherein a valve opening period is set shorter than a second predetermined valve opening period shorter than the predetermined valve opening time. 3. The valve opening period of the intake valve, wherein the pressure in the intake pipe of the engine becomes equal to or less than a predetermined pressure when the opening of the throttle valve is smaller than the predetermined opening. Item 3. The method for controlling deceleration of an internal combustion engine according to item 1 or 2. 4. An opening period of said intake valve from zero to said predetermined period according to an operation state of said engine until said opening degree of said throttle valve becomes smaller than said predetermined opening degree in said deceleration control. The deceleration control method for an internal combustion engine according to claim 1 or 2, wherein the control is performed so that the period is set to a period between the two. 5. An opening period of the intake valve and an opening degree of the throttle valve or an opening degree of the throttle valve so that an intake pressure of the engine becomes a target intake pressure when an opening degree of the throttle valve becomes smaller than the predetermined opening degree. 2. The method according to claim 1, wherein at least one of the opening degrees of the throttle bypass valve is controlled.
3. A method for controlling deceleration of an internal combustion engine according to claim 2. 6. The engine according to claim 1, wherein the detection of the deceleration state of the engine is performed based on at least one of an accelerator opening and an accelerator opening speed, and the engine operating parameter including at least the engine speed. Deceleration control method for an internal combustion engine.