JP2003083117A - Fuel injection control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid over-rich temporarily generated when switching a stopping valve from a non-operating state to an operating state. SOLUTION: A valve stopping mechanism 53 holds at least one of a plurality of intake valves provided for every cylinder in an opened state in a predetermined engine speed region. A fuel injection valve 16 is provided in a common intake passage branched into a plurality of intake ports 441 and 451 to be opened/closed by the plurality of intake valves. A fuel injection quantity calculating part 15 determines fuel required quantity based on an engine state. A leaning factor reducing part 13 reduces a leaning factor for fuel required quantity and executes leaning in an operation region where the valve stopping mechanism 53 is switched to the non-operating state by escaping from the predetermined engine speed region. Leaning is stepwise performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection control device, and more particularly to a fuel injection control device for an engine having a plurality of sets of supply / exhaust valves for each cylinder.

[0002]

2. Description of the Related Art In an engine having a plurality of sets of intake / exhaust valves for each cylinder, at least one intake valve is deactivated in a planned operation range (for example, a low engine speed range) to maintain a closed state. Engines with a pause mechanism are known. 1
By keeping the two intake valves closed, a swirl is formed in the combustion chamber to enable lean combustion and reduce fuel consumption. In an engine equipped with this valve suspension mechanism, when the intake valve is out of the planned operating range, the intake valve in the non-operating (resting) state is switched to the operating state, but at that time, the fuel supply state changes suddenly, so that the engine operation is stopped. The condition may change suddenly and the driver may feel discomfort.

Proposals have been made to solve this problem. For example, in Japanese Unexamined Patent Application Publication No. 2000-204956, in order to prevent the fuel accumulated in the inhaled intake passage from flowing into the combustion chamber at one time, the intake passages connected to a plurality of intake ports are connected by a communication passage. There is disclosed an engine in which fuel is prevented from accumulating in an intake path leading to a dormant intake valve.

In Japanese Utility Model Publication No. 63-15553, in order to prevent an overrich of the air-fuel mixture due to a delay in the timing of operating the valve during rest, a delay in the timing of opening the valve during rest is taken into consideration. An engine is disclosed in which the timing of increasing the supply fuel amount is delayed.

Further, Japanese Patent Laid-Open No. 7-293305 discloses a dedicated intake port corresponding to an intake valve with a rest state (rest intake valve) and an intake valve without a rest state (service intake valve). An engine provided with a fuel injection valve and controlling each independently is disclosed.

[0006]

The above-mentioned conventional device still has a problem to be solved. First, in an engine in which accumulated fuel is allowed to escape to the intake passage corresponding to the service valve through the communication passage, when the fuel spray of the fuel injection valve is directed to both the pause valve and the service valve, the accumulated fuel is sufficiently discharged to the service valve side. It may not be possible to escape. In addition, an engine that delays the supply fuel amount increase timing can cope with a mechanical operation delay of a valve, but the problem of preventing temporary overrich due to inflow of stagnant fuel has not been solved. Further, in an engine provided with a plurality of fuel injection valves, there are problems that the number of parts increases and the number of assembling steps increases, and the degree of freedom in the layout of the intake device also decreases.

In view of the above problems, it is an object of the present invention to provide a fuel supply control device capable of preventing a temporary overrich due to the inflow of fuel accumulated in an intake passage corresponding to a pause valve.

[0008]

To achieve the above object, the present invention maintains at least one of a plurality of intake valves provided for each cylinder in a closed state in a predetermined operating range. An engine that has a valve pausing means and a fuel injection device that is provided in a common intake passage that branches into a plurality of intake ports that are opened and closed by the plurality of intake valves, and that determines a fuel demand amount based on the engine state. In the fuel injection control device, in the operating range in which the valve deactivating means is switched to the non-operating state by leaving the planned operating range, the leaning means for performing the leaning correction for the fuel demand amount is provided. There are 1 characteristics.

Further, the present invention has a second feature in that it includes a return canceling means for canceling the lean correction stepwise in an operating range after the valve stopping means is switched to the non-operating state. .

Further, according to the present invention, the operating range is set on the basis of the engine speed, and the valve pausing means is switched to the inoperative state in a region where the engine speed exceeds a predetermined engine speed. A third feature is that the lean correction is performed stepwise from a low engine speed range lower than the predetermined engine speed.

The present invention also has a fourth point in that the leaning degree by the leaning means is determined so as to be large when the engine temperature is low and small when the engine temperature is high, according to the engine temperature. The fifth characteristic is that the lean correction is released in stages when the lean correction is continued for a predetermined time or longer.

The accumulated fuel in the intake port that was closed when the valve pausing means was in operation was temporarily flown in from the intake port that was opened when the valve pausing means was in an inactive state, and the air-fuel mixture became overrich. Cheap. According to the first feature, since the lean correction is performed in the operation range in which the valve deactivating means is switched to the inoperative state, the overrich can be avoided.

Particularly, according to the second feature, the operating range in which the valve stopping means is switched to the non-operating state (stop switching operating range)
After that, the fuel supply amount is gradually returned to the fuel demand amount. According to the third feature, the valve resting means is switched between operating and non-operating based on the engine speed. Then, the lean correction is started from the engine speed range lower than the engine speed range set for this switching.
Therefore, when the valve deactivating means is switched to the operating state, the lean correction is sufficiently performed. According to the second and third characteristics, the lean output and the return are performed in a stepwise manner, so that the output fluctuation of the engine is small.

According to the fourth feature, the amount of fuel retained in the intake port that is still closed increases as the engine temperature decreases, so the lean correction is increased when the engine temperature is low. To do. Further, according to the fifth feature, it is possible to prevent excessive leaning when the engine is continuously operated in the pause switching operation range.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a side view of the motorcycle having the fuel injection control device according to the embodiment of the present invention. The vehicle body frame 21 of the motorcycle 2 includes a head pipe 23 provided at a front portion of the vehicle body, and a main frame 22 having a front end coupled to the head pipe 23 and bifurcated to the left and right of the vehicle body and extending rearward of the vehicle body. Mainframe 2
2 has a substantially U-shape that opens upward in a side view. A seat stay 25 extending rearward and obliquely upward is coupled to a rear end of the main frame 22, and a coupling frame 24 is coupled between the rear ends.

A front fork 26 pivotally supported by the head pipe 23 is provided, a steering handle 27 is connected to an upper portion of the front fork 26, and front wheels WF are attached to a lower portion thereof. Rear fork 2 supporting the rear wheel WR
8 is supported by the rear portion of one main frame 22 so as to be vertically swingable, and a pair of left and right cushion units 29 is provided between the seat stay 25 and the rear wheel WR.

Main frame 22 and connecting frame 2
4, a fuel tank 31 is mounted above the engine E, and a tandem seat 32 is mounted on the seat stay 25.

The engine E is supported by the main frame 22 and the connecting frame 24, and the output of the engine E is transmitted to the rear wheels WR via a transmission and a chain transmission device 30 incorporated in the engine E. A radiator 33 is arranged in front of the engine E. The engine E can have a plurality of cylinders (here, four cylinders), and each cylinder is provided with a plurality of intake ports and exhaust ports.

FIG. 3 is a sectional view of the main part of the cylinder head of the engine E, and FIG. 4 is a view taken along the line AA of FIG. The parts shown in these figures are provided for the number of cylinders of the engine E. In the figure, the cylinder head 40 has a combustion chamber 43
The first intake port 44 and the second intake port 4 that open to face the
5 and the first exhaust port 4 that opens toward the combustion chamber 43
6 and the second exhaust port 47 are provided. First intake port 44
The first exhaust port 46 and the first exhaust port 46 are arranged at substantially symmetrical positions with respect to the center of the combustion chamber 43, and the second intake port 45 and the second exhaust port 47 are similarly arranged.

The first intake port 44 and the first exhaust port 46 have a paused intake valve and a paused exhaust valve which are inoperative in the low speed range. On the other hand, the second intake port 45 and the second exhaust port 47 are associated with the rotation of the engine regardless of the engine speed.
It has a regular intake valve and a regular exhaust valve that open and close at a predetermined timing.

A first intake passage 44 connected to the first intake port 44
1 and the second intake passage 451 connected to the second intake port 45 are integrally connected to the intake port 48. Intake port 4
An intake pipe is connected to 8 and a fuel injection valve is provided in the intake pipe (neither is shown). Similarly, the first exhaust path 461 connected to the first exhaust port 46 and the second exhaust path 471 connected to the second exhaust port 47 are integrally connected to the exhaust port 49. An exhaust pipe (not shown) is connected to the exhaust port 49. As shown in FIG. 4, the bifurcated first intake passage 441 and the second intake passage 451 are provided with a connecting passage 50 that connects them to each other near the combustion chamber 43. This connecting path 50
As a result, fuel staying in the first intake passage 441 is released to the second intake passage 451 side while the rest intake valve is resting, that is, while the closed intake valve is closed.

The first intake port 44 and the second intake port 4
5, and the first exhaust port 46 and the second exhaust port 47 are provided with valve mechanisms for opening and closing each. The valve mechanism of the first intake port 44 and the second exhaust port 47 will be described with reference to FIG. A valve body 51 as a resting intake valve that engages with the first intake port 44 has a stem 511 extending upward, and this stem 511 is slidably supported by a guide cylinder 52 fixed to the cylinder head 40. To be done. Stem 511
The upper end of is engaged with an intake valve cam (not shown) via a valve pausing mechanism 53.

The valve pausing mechanism 53 is the first in the planned low rotation speed range.
It is a mechanism that suspends the transmission of the driving force by the intake valve cam to the valve body 51 in order to keep the intake port 44 closed. The coil spring 54 for urging the stem 511 upward (in the valve closing direction) is provided with the stem 511 and the cylinder head 4.
0, and a coil spring (described later) is also provided between the valve pause mechanism 53 and the cylinder head 40.

The valve body 55 that engages with the second exhaust port 47 has a stem 551, and this stem 551 is the cylinder head 4.
It is slidably supported by a guide cylinder 56 fixed to zero. The upper end of the stem 551 is engaged with an exhaust valve cam (not shown). A coil spring 57 for urging the stem 551 upward (in the valve closing direction) is provided between the stem 551 and the cylinder head 40.

The valve mechanism of the second intake port 45 is constructed similarly to the valve mechanism provided in the second exhaust port 47, and does not have a valve resting mechanism. On the other hand, the first exhaust port 46, which is paired with the first intake port 44, may have a valve resting mechanism, like the first intake port 44. In this case, the second intake port 45 and the first
The cross-sectional shape including the exhaust port 46 is similar to that in FIG.

Next, the valve stop mechanism 53 will be described in detail. Figure 5
FIG. 6 is a sectional view of the valve resting mechanism 53. Cylinder head 40
A cylindrical lifter 61 having a bottom is provided slidably in a support hole 60 provided at the bottom. A pin holder 62 is fitted inside the lifter 61. Pin holder 6
2 has an annular groove 621 on the periphery thereof, and the outer peripheries of the upper and lower flanges forming the annular groove 621 are in contact with the inside of the lifter 61, and the annular groove 621 and the inner surface of the lifter 61 cooperate with each other. It defines the passage for hydraulic oil described below.

A space 622 is formed inside the pin holder 62 for slidably accommodating the pin, that is, the plunger 63. The space 622 extends in the diameter direction of the pin holder 62 through the center of the pin holder 62, and the plunger 63 is slidably accommodated therein. Plunger 6 in space 622
A coil spring 64 for urging 3 in the right direction in the drawing is housed. The deviation limit of the plunger 63 is defined by the stopper pin 65. The stopper pin 65 defines the deviation limit of the plunger 63, and also defines the position of the plunger 63 in the rotational direction with respect to the pin holder 62. The pin holder 62 and the plunger 63 have escape holes 623 and 631 which are aligned in a line on the extension of the stem 511 of the valve mechanism when the plunger 63 is biased to the right in the drawing and positioned at the bias limit.

An annular groove 401 is formed in the support hole 60 along the circumferential direction of the lifter 61. The lifter 61 has
A communication port 611 that connects the annular groove 621 formed around the pin holder 62 and the annular groove 401 is provided. The respective positions of the annular grooves 401 and 621 and the communication port 611 are set so that the lifter 61 communicates with each other regardless of the position in the support hole 60.

Hydraulic oil supply passage 65 connected to the annular groove 401
Is provided. The hydraulic oil supply passage 65 is connected to a hydraulic oil supply source (neither is shown) via a hydraulic oil control valve.
The hydraulic oil is the hydraulic oil supply passage 65, the annular groove 401, the communication port 61.
1, and is supplied to the annular passage 621, and a pressure is applied to the open end of the pin holder 62, that is, the right end of the plunger 63 in a direction of compressing the coil spring 64.

Between the lifter 61 and the cylinder head 40,
A coil spring 66 that biases the lifter 61 upward is provided. The upper end of the spring 54 that urges the valve body 51 upward contacts the stopper 512 fixed to the stem 511. On the other hand, the upper end of the lifter 61 contacts the intake valve cam 67,
When this cam 67 rotates, it responds along its outer circumference.
(Moves up and down).

According to the above construction, the first intake port 44 and the second intake port 45, the first exhaust port 46 and the first exhaust port 46 and the second intake port 45 respond to the intake valve cam and the exhaust valve cam which rotate with the rotation of the engine. The valve mechanism provided in each of the two exhaust ports 47 operates. Here, the valve mechanism provided at the second intake port 45 and the second exhaust port 47 always opens and closes the valve in response to the intake valve cam and the exhaust valve cam. On the contrary,
The valve mechanism provided at the first intake port 44 and the first exhaust port 46 has a valve resting mechanism 5 in a predetermined engine low speed range.
Due to the action of 3, it does not operate regardless of the rotation of the intake valve cam and the exhaust valve cam. As a result, the valve body 511 forming the valve mechanism is held by the coil spring 54 while being urged upward.

That is, the operation of holding the first intake port 44 in the closed state is as follows. In the operating state of the valve mechanism, the hydraulic oil is fed to the annular groove 401 via the hydraulic oil supply passage 65. Then, the hydraulic pressure acts on the end portion (the right end portion in the figure) of the plunger 63 through the communication port 611 and the annular groove 621, and the plunger 63 compresses the coil spring 64 and biases it to the left side in the figure. As a result, the escape hole 631,
623 is no longer aligned with the extension of the stem 511, and the upper end of the stem 511 faces the lower surface of the plunger 63. Therefore, when the cam 67 rotates and the lifter 61 is pushed down according to the amount of eccentricity, the stem 511 pushed by the lower surface of the plunger 63 descends,
The valve mechanism opens and the first intake port 44 opens.

When the cam 67 rotates and the power 67 comes into contact with the lifter 61 at a portion where the eccentricity is small, the lifter 61 urged by the coil spring 66 follows the cam 67, and accordingly, the coil 67 moves. Stem 54 by spring 54
1 is also pushed up and closed. In this way, the first intake port 44 responds to the cam 67 that rotates as the engine rotates.

On the other hand, when the valve mechanism is not in operation, the hydraulic oil is released through a path (not shown) to release the hydraulic pressure. Then, since the plunger 63 is biased by the coil spring 64, it is biased to the right in the figure. As a result, the escape hole 63
1, 623 are aligned on the extension line of the stem 511, and the upper end of the stem 511 can enter the escape holes 631, 623. Therefore, even if the cam 67 rotates and the lifter 61 is pushed downward in accordance with the amount of eccentricity, the stem 511 escapes into the escape holes 631 and 623.
Does not follow the movement of the lifter 61. Therefore, the valve mechanism is held in the closed state, and the first intake port 44 and the first exhaust port 46 remain closed. The first intake port 44
And the valve mechanism of the first exhaust port 46 operate in the same manner.

The details of the above-mentioned valve resting mechanism 53 are described in Japanese Patent Application Laid-Open No. 2000-2045 which is a patent application of the present applicant.
No. 6), and for further understanding of the present invention, the disclosures of the publication can be referred to by being integrated into the present specification.

Next, the fuel supply control when the valve mechanism is switched from the non-operating state to the operating state will be described. In the present embodiment, at the time of this switching, the fuel injection amount is set smaller than the engine required fuel amount, and control is performed so that the air-fuel mixture becomes lean.

FIG. 6 is a timing chart of fuel supply control. In the figure, based on the control switching speed NEVTC (for example, 6800 rpm), the engine speed NE
When is low, the solenoid that supplies the hydraulic pressure to the valve stop mechanism 53 is turned off, and the first intake port 44 and the first exhaust port 46 are kept closed. On the other hand, when the engine speed NE is equal to or higher than the control switching speed NEVTC, the solenoid that supplies the hydraulic pressure to the valve stop mechanism 53 is turned on, and the first intake port 44 and the first exhaust port 46 are opened and closed according to the engine speed. To do so.

A valve (resting side valve) provided at the first intake port 44 and the first exhaust port 46 has a scheduled time (lean recovery start timer tmKV described later) after the solenoid is turned on.
It is driven after a time corresponding to TLNH, for example, 50 msec.

The lean process, that is, the process of reducing the lean coefficient KVTLN, is carried out when the engine speed exceeds the lower limit engine speed NEVTCL (for example, 6400 rpm). Since the engine speed exceeds the lower limit engine speed NEVTCL, the lean coefficient KVTLN is reduced by one step (lean coefficient shift amount) every predetermined processing cycle to the minimum lean coefficient (for example, 0.57). It The minimum leaning coefficient is set to a smaller value as the temperature increases, depending on the temperature of the cooling water of the engine.

When the leaning coefficient KVTLN is maintained in the leaning state for the scheduled time (1.0 or less), that is, when the engine speed is stable in the planned low speed range,
It is controlled to return to 1.0. The process of returning the leaning coefficient KVTLN is performed from the time when the valve on the rest side is driven.
The process of returning the leaning coefficient KVTLN is increased by one step (leaning coefficient returning amount).

The fuel injection amount is determined by a known method using a map or the like according to the required fuel amount of the engine determined using various parameters. The fuel injection amount determined here is multiplied by the leaning coefficient KVTLN to correct the fuel injection amount. Leaning is started from the lower limit engine speed NEVTCL, and leaning is maintained until the return operation of the leaning coefficient KVTLN is completed. The fuel accumulated in the intake air passage on the rest side flows in at one time during the valve opening operation, and the air-fuel ratio A / F is temporarily increased.
May decrease from the stoichiometric air-fuel ratio. However, according to the present embodiment, since leaning is performed in advance to reduce the fuel supply amount, a sudden decrease in the air-fuel ratio A / F is suppressed.

7 and 8 are flowcharts of the fuel supply control, particularly, the flowchart of the lean coefficient calculation of the air-fuel mixture. In FIG. 7, in step S1, the leaning coefficient KVTLN that determines the leaning degree of the air-fuel mixture is 1.
It is determined whether it is less than 0. Leaning coefficient KVTLN is 1.0
If it is not less than the above, the process proceeds to step S2, and depending on whether or not the ratio NE / V between the engine speed NE and the vehicle speed V is greater than a threshold value, the transmission is switched between the high gear ratio side (low gear side) and the low gear ratio. Determine whether it is the ratio side (high gear side). This is for setting data according to the switching position of the transmission.

If it is on the low gear side, the process proceeds to step S3, and if it is on the high gear side, the process proceeds to step S4. Step S3
In step S4, data for the low gear side and data for the high gear side are set, respectively. Leaning lower limit throttle opening (hereinafter referred to as "lower limit throttle opening") THVTLN, leaning lower limit engine speed (lower limit speed) NEVTCL, 4 valves (4 valve mechanisms of each cylinder are in operable state) Data) for the return to lean timer TMKVTH,
Data for lean recovery timer with two valves (when one pair of supply / exhaust among the four valve mechanisms of each cylinder is operable) TMKVT
Each data of the leaning coefficient shift amount DKVTL for L, 2 valves, and the leaning coefficient return amount DKVTLD for 4 valves is read from the storage unit (ROM, etc.) and set respectively. The suffix "1" of the sign of the data to be set is the low gear side data,
The same "2" indicates data for the high gear side.

In steps S5 and S6, the minimum leaning coefficient TW-K corresponding to the engine water temperature is obtained.
The table in which VTLN0L and TW-KVTLN0H are set is searched and the minimum lean coefficient KVTLN0 is set.

In step S7, the flag F-VTSH indicating whether or not the solenoid for applying the hydraulic pressure of the hydraulic oil to the valve pause mechanism 53 is turned on is identified. When the solenoid is on, it is assumed that the plunger 63 of the valve stop mechanism 53 is hydraulically biased and the valve mechanism responds to the cam 67 (operable state). When the solenoid is on, the process proceeds to step S8.

In step S8, the lean return timer data TMKVTL for two valves is set in the lean return timer tmKVTL for two valves. In step S9, it is determined whether or not the lean recovery start timer tmKVTLNH for four valves has become "0" or less. The value of this timer tmKVTLNH is 1.0 for the lean coefficient KVTLN after the solenoid is energized.
Corresponds to the delay time until the operation to return to is started. If step S9 is affirmative, the process proceeds to step S10 to determine whether the lean coefficient KVTLN is less than 1.0.

If the leaning coefficient KVTLN is less than 1.0, the routine proceeds to step S11, where the leaning coefficient return amount DKVTLD.
Is added to the current leaning coefficient KVTLN to obtain the leaning coefficient K
Update VTLN. In step S12, the leaning coefficient KV
Judge whether TLN is 1.0 or more. If step S12 is affirmative, that is, if the leaning coefficient KVTLN has returned to 1.0 or more, the process proceeds to step S13 to set 1.0 as the leaning coefficient KVTLN. On the other hand, if it is determined in step S10 that the leaning coefficient KVTLN is not less than 1.0, the process proceeds to step S13 and 1.0 is set as the leaning coefficient KVTLN.

As described above, when the solenoid is on, that is, all valve mechanisms for the first and second intake ports 44, 45 and the first and second exhaust ports 46, 47 are always operable (4 When the valve is switched to), the lean coefficient KVTLN is returned to 1.0, so the fuel supply amount is controlled so that the air-fuel mixture is as required by the engine.
Leaning is released.

When it is determined in step S7 that the solenoid is off, it is determined that the valve is in the 2-valve state. Refer to FIG. 8 for the processing at the time of two valves. In FIG. 8, in step S14, the data TM for the lean return timer at the time of 4 valves is used.
Set KVTH to the lean recovery timer tmKVTH for 4 valves. In step S15, it is determined whether or not switching from the 4-valve state to the 2-valve state is permitted by flag F-.
Judge by identifying TWVTS. When the cooling water temperature of the engine E is higher than the predetermined value, it is considered that the warm-up has ended, and the switching to the 2-valve state is permitted, and the flag F-TWVTS is set (= 1). On the other hand, when the cooling water temperature of the engine E is lower than the predetermined value, it is considered that the engine E has not been warmed up, the switching to the 2-valve state is prohibited, and the flag F-TWVTS is cleared (= 0).

If the switching to the 2-valve state is permitted, the routine proceeds to step S16, where it is judged whether the engine E is in the no-load state by identifying the flag F-NOLOAD. For example, when the clutch is off or the transmission is in the neutral position, no load is considered and the flag F-NOLOAD is set. If the clutch is on or the transmission is not in the neutral position, it is considered to be under load and the flag is F-NOLOAD.
Is cleared.

If there is a load, step S17
To the lower throttle opening THVTLN
Judge whether L or more. That is, leaning is not performed below the lower limit throttle opening. Step S1
If 7 is affirmative, the routine proceeds to step S18, where the lower limit engine speed NEVT
Judge whether CL or more. That is, leaning is not performed below the lower limit rotation speed.

The engine water temperature is higher than the predetermined temperature (Yes at Step S15), the engine E is under load (No at Step S16), and the throttle opening TH and the engine speed NE both exceed the respective lower limit values. If yes (steps S17 and S18 are both positive), the process proceeds to step S19.

In step S19, it is determined whether or not the 2-valve lean recovery timer tmKVTL is "0" or less. If step S19 is negative, proceed to step S20,
It is determined whether the current lean coefficient KVTLN is less than or equal to the minimum lean coefficient KVTLN0. That is, it is determined whether or not the leaning coefficient KVTLN has been reduced to the minimum leaning coefficient KVTLN0 corresponding to the engine water temperature. If step S20 is affirmative, the process proceeds to step S21 to replace the lean coefficient KVTLN with the table value KVTLN0.

If the current leaning coefficient KVTLN is not less than or equal to the minimum leaning coefficient KVTLN0, the process proceeds to step S22, and the leaning coefficient shift amount DKVTL is set to the current leaning coefficient K.
Update leaning coefficient KVTLN by subtracting from VTLN. In step S23, similarly to step S20, it is determined whether or not the current leaning coefficient KVTLN is equal to or less than the minimum leaning coefficient KVTLN0. If this determination is affirmative, the process proceeds to step S21.

In this way, the lean coefficient KVTLN is gradually reduced by the lean coefficient shift amount DKVTL to the predetermined minimum lean coefficient KVTLN0.

If step S19 is affirmative, that is, if the two-valve lean recovery timer tmKVTL is "0" or less, it is determined that the time scheduled for maintaining the lean state has elapsed and the routine proceeds to step S24, where the lean The process of returning the conversion coefficient KVTLN is started. First, in step S24, it is determined whether the lean coefficient KVTLN is less than 1.0. If the leaning coefficient KVTLN is not less than 1.0, the process proceeds to step S25 and the leaning coefficient KVTLN is set to 1.0. If the leaning coefficient KVTLN is less than 1.0, it means that leaning is in progress, so the process proceeds from step S24 to step S26, where the leaning coefficient transition amount DKVTL is added to the current leaning coefficient KVTLN to obtain the leaning value. Update KVTLN. Step S27
Then, it is determined whether the lean coefficient KVTLN has become 1.0 or more. If step S27 is affirmative, step S2
Go to 5.

If step S15 is negative, step S16 is affirmative, step S17 is negative, or step S18 is negative, the process proceeds to step S28 and the lean recovery timer data TMKVTL for 2 valves is set to 2 valves. Set to the lean recovery timer tmKVTL. In step S29, it is determined whether the leaning coefficient KVTLN is less than 1.0. If the result in step S29 is negative, the lean value KVTLN is set to 1.0 in step S30. Leaning coefficient K
If VTLN is less than 1.0, the process proceeds from step S29 to step S31 to add the leaning coefficient shift amount DKVTL to the current leaning coefficient KVTLN to update the leaning coefficient KVTLN. In step S32, the leaning coefficient KVTLN is 1.
It is determined whether or not the value has returned to 0 or more. If this judgment is affirmative, it is considered that the recovery has ended and the routine proceeds to step S30, where the lean value KVTLN is set to 1.0.

FIG. 1 is a block diagram showing the main functions of the lean coefficient calculation. In the figure, the engine speed detector 4 detects the engine speed NE based on the output of the engine speed sensor 5. The solenoid control unit 6 outputs a command to drive the solenoid 7 that supplies hydraulic pressure to the valve pausing mechanism 53 when the engine speed is equal to or higher than the control switching speed NEVTEC. The solenoid 7 energizes the hydraulic oil supply source 8 to apply hydraulic pressure to the valve pause mechanism 53. The throttle opening detector 9 detects the rotation angle of the throttle sensor 10 to detect the throttle opening.

Based on the engine speed NE, the throttle opening TH, the drive command for the solenoid, and the lean lower limit engine speed NEVTCL, the engine speed region determination unit 11 determines whether the engine speed NE is in the scheduled region for leaning. Determine which one corresponds. When the engine speed NE is equal to or higher than the lower limit speed NEVTCL, the throttle opening is equal to or higher than the lower limit opening, and the solenoid drive command is off, the lean coefficient reduction unit 12 is activated and the lean coefficient KVTLN is Will be reduced.

When the drive command for the solenoid is turned on, the leaning coefficient restoring unit 13 is energized, and the leaning coefficient is restored.
KVTLN restoration processing (increasing processing) is performed. The recovery process ends when the lean coefficient KVTLN reaches 1.0. Also, when the leaning coefficient reducing unit 12 is energized for the scheduled time, the leaning coefficient restoring unit 13 is energized.

The lean coefficient KVTLN of the lean coefficient setting section 14 is increased / decreased by the lean coefficient reducing section 12 and the lean coefficient restoring section 13, and the lean coefficient KVTLN is supplied to the fuel injection amount calculation section 15 to be leaned. The calculation of the fuel injection amount including conversion is performed. The fuel injection valve 16 is driven according to the duty ratio of the ON time and the OFF time based on the calculated fuel injection amount.

In the above-described embodiment, a hydraulically actuated valve stopping mechanism is assumed. However, the present invention is not limited to this, and includes a mechanism for holding at least one intake port among a plurality of sets of intake ports and exhaust ports in a planned low rotation speed range regardless of the rotation of the engine. Widely applicable to running engines.

[0063]

As is apparent from the above description, according to the first to fifth aspects of the present invention, the lean correction is used to eliminate the overrich caused by the inflow of the fuel accumulated in the intake port at rest. be able to. Therefore, it is possible to suppress fluctuations in engine output and generation of unburned hydrocarbons. In particular, these effects can be achieved regardless of a complicated structure such as providing a plurality of fuel injection valves in each cylinder.

Further, according to the second and third aspects of the invention, since the lean correction and the restoration thereof are gradually performed, the output fluctuation of the engine can be further alleviated.

According to the fourth aspect of the present invention, in view of the fact that the staying fuel during rest depends on the engine temperature, the degree of leaning can be increased when the engine temperature is low. Further, according to the invention of claim 5, when the engine speed is stable in the stop switching operation range, excessive leaning is suppressed to ensure stability of the output in the stop switching operation range. can do.

[Brief description of drawings]

FIG. 1 is a block diagram showing main functions of a control device according to an embodiment of the present invention.

FIG. 2 is a side view of the motorcycle having the control device according to the embodiment of the present invention.

FIG. 3 is a cross-sectional view of a cylinder head of an engine.

FIG. 4 is a bottom view of the cylinder head of the engine.

FIG. 5 is a sectional view of a valve pausing mechanism.

FIG. 6 is a timing chart of fuel supply control.

FIG. 7 is a flowchart (part 1) of fuel supply control.

FIG. 8 is a flowchart (part 2) of fuel supply control.

[Explanation of symbols]

2 ... Motorcycle, 4 ... Engine speed detection unit, 5 ...
Rotation speed sensor, 6 ... Solenoid control unit 6, 7 ... Solenoid, 10 ... Throttle sensor, 11 ... Engine rotation speed range determination unit, 12 ... Leaning coefficient reduction unit, 13
... Leaning coefficient returning section 13, 14 ... Leaning coefficient setting section, 15 ... Fuel injection amount calculating section, 40 ... Cylinder head, 43 ... Combustion chamber, 44 ... First intake port, 45 ... Second intake port, 46 ... First exhaust port, 47 ... Second exhaust port,
50 ... Communication port, 53 ... Valve stop mechanism, 62 ... Pin holder, 63 ... Plunger

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02D 43/00 301 F02D 43/00 301H 301Z 45/00 312 45/00 312N 312Q (72) Inventor Tomoya Kono Wako, Saitama 1-4-1 Chuo City, Ltd. Honda R & D Co., Ltd. (72) Inventor Yoshiaki Shiro 1-4-1 Chuo 1-4-1, Wako City, Saitama Prefecture F-term in Honda R & D Co., Ltd. (reference) 3G084 BA09 BA13 BA23 DA12 EA11 EC01 FA10 FA20 FA33 3G092 AA05 AA11 BA04 BB01 DA01 DA03 DA11 EA07 EA08 FA05 HA06Z HE01Z 3G301 HA01 HA19 JA04 KA23 LA07 MA01 MA11 NE15 NE24 PA11Z PE01Z PE08Z

Claims (5)

[Claims] 1. A valve suspension means for holding at least one of a plurality of intake valves provided for each cylinder in a closed state in a predetermined operating range, and a plurality of a plurality of intake valves opened and closed by the plurality of intake valves. A fuel injection control device for an engine, comprising: a fuel injection device including a fuel injection valve provided in a common intake passage branched to an intake port; and determining a fuel demand amount based on an engine state, The fuel injection control device is provided with leaner means for performing leaner correction on the required fuel amount in an operating range in which the valve resting means is switched to a non-operating state by removing. 2. The fuel injection according to claim 1, further comprising return canceling means for canceling the lean correction stepwise in an operating range after the valve deactivating means is switched to a non-operating state. Control device. 3. The lean operating correction is configured such that the operating range is set based on an engine speed, and the valve deactivating means is switched to a non-operating state in a region exceeding a predetermined engine speed. 2. The fuel injection control device according to claim 1, wherein the fuel injection control is performed stepwise from a lower engine speed range than the predetermined engine speed. 4. A means for detecting an engine temperature is provided, and the leaning degree by the leaning means is determined so as to be large when the engine temperature is low and small when the engine temperature is high according to the engine temperature. The fuel injection control device according to claim 1, wherein: 5. The fuel injection control device according to claim 1, wherein, when the lean correction is continued for a predetermined time or longer, the lean correction is released stepwise.