JP2763808B2 - Fuel injection control device for engine with continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a fuel for an engine with a continuously variable transmission in which a basic fuel injection pulse width in which a correction value for acceleration increase at start is added is stored in a basic fuel injection map. The present invention relates to an injection control device.

[Problems to be Solved by the Related Art and the Invention] Generally, when setting the fuel injection amount of the injector,
For example, as disclosed in Japanese Utility Model Application Laid-Open No. 58-169117, the intake air amount detected by the intake air amount sensor and the engine speed are set as parameters, or
For example, as disclosed in Japanese Patent Application Laid-Open No. 63-255543, there is a method in which a pressure on the downstream side of a throttle valve detected by a pressure sensor and an engine speed are set as parameters.

Further, for example, JP-A-63-29039, JP-A-63-1
As disclosed in Japanese Patent No. 83247, a so-called α-N control method in which an intake air amount is estimated from a throttle valve opening α detected by a throttle opening sensor and an engine speed N without using a sensor. Some adopt.

This α-N control method is relatively frequently used in a two-stroke engine or the like because the structure can be simplified and the cost is excellent because an intake air amount sensor or a pressure sensor is not required. .

Incidentally, also in the α-N control, when the throttle valve is suddenly opened such as when the vehicle starts, it is necessary to perform an acceleration increase correction.

For example, Japanese Patent Application Laid-Open No. 57-116138 discloses a map in which normal operation is determined to be in a transient state based on the opening speed of a throttle valve, and during normal operation, a suction pipe negative pressure and an engine speed are used as parameters. A technique is disclosed in which a basic fuel injection pulse width is set from the following equation, and when a transient state is determined, the basic fuel injection pulse width is set from another map using the throttle opening and the engine speed as parameters.

In this prior art, two types of maps are selectively used according to driving conditions, so that a large storage capacity is required, and a calculation function for distinguishing between a normal operation and a transition is complicated, and the capacity of the microcomputer is increased. However, there is a problem that the size becomes large.

In the case of an engine with a continuously variable transmission, the gear ratio is variably set according to the engine speed and the engine load. The number range is almost constant. Therefore, when the basic fuel injection pulse width is set from a map in which the basic fuel injection pulse width during transition is set to a load region except for the idle region as in the above prior art, the engine load suddenly increases on the clutch meet line. In such a case, the output becomes insufficient and sufficient acceleration performance cannot be obtained.

[Object of the Invention] The present invention has been made in view of the above-mentioned conventional problems. Therefore, the present invention provides a continuously variable operation that simplifies arithmetic processing, reduces the load on a microcomputer, and obtains sufficient acceleration performance when starting. It is an object of the present invention to provide a fuel injection control device for an engine with a transmission.

Means and Action for Solving the Problems In order to solve the above-mentioned conventional problems, the present invention provides a basic fuel injection pulse width based on a basic fuel injection pulse width map using an engine speed and a throttle opening as parameters. In the fuel injection control device for an engine with a continuously variable transmission having a basic fuel injection pulse width setting means for setting, the basic fuel injection pulse width stored in the vicinity of the no-load region of the clutch meet line in the basic fuel injection pulse width map is set. , Which is set to a value that takes into account the acceleration increase correction value.
The basic fuel injection pulse width in consideration of the acceleration increase correction value is set so as to increase stepwise as the throttle opening and the engine speed increase.

According to such a configuration, the acceleration increase correction at the time of starting is not required, the calculation process is simplified, and the load on the microcomputer is correspondingly reduced, and in the vicinity of the clutch meet line where the load is suddenly increased. Sufficient output can be obtained.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 is a functional block diagram of a fuel injection control device, FIG. 2 is an overall schematic diagram of an engine control system, FIG. 3 is a cross-sectional view of a continuously variable transmission, FIG. FIG. 5 is a conceptual diagram of a basic fuel injection pulse width map, and FIG. 5 is a flowchart showing a fuel injection control procedure.

(Configuration of Engine Control System) Reference numeral 1 in FIG.
In the engine body of the cycle engine, a crankcase 2 and a cylinder block 3 of the engine body 1 are integrally formed. Further, a crankshaft 4a is provided in a crankcase 2a which also serves as a preload chamber provided in the crankcase 2.
Is installed horizontally. A piston 5 is connected to the crankshaft 4 via a connecting rod 6,
Further, a combustion chamber 7 is formed above the piston 5 of the engine body 1, and the combustion chamber 7 and the crank chamber 2a are formed.
Are communicated via a scavenging passage (not shown).

In addition, the exhaust port 8 provided in the cylinder block 3 and the scavenging passage (not shown) can be freely opened to the combustion chamber 7 and the crank chamber 2a when the piston 5 is used as a valve during reciprocating motion. You.

Further, the cylinder block 3 is provided with an intake port 9 that can freely communicate with the crank chamber 2a at a predetermined timing via a reed valve (not shown) or a rotary valve that rotates synchronously with the crankshaft 4. A throttle body 11 is fixed to the opening end of the intake port 9 via an insulator 10, and an air box 12 for storing an air cleaner (not shown) is fixed to an air horn 11a of the throttle body 11. . Reference numeral 13 denotes an ignition plug, which is connected to the secondary side of the ignition coil 13a.

Also, the throttle valve 11 of the throttle body 11
An injector 14 faces the downstream side of b. A fuel tank 17 is connected to the injector 14 via a fuel passage 15 and a fuel return passage 16. Further, the fuel passage
15, a fuel filter 18 and a fuel pump 19 are interposed from the fuel tank 17 side, and the fuel return passage 16 is provided with a pressure downstream of the throttle valve 11 b and a fuel pressure in the fuel passage 15. A pressure regulator 19 for maintaining a constant differential pressure is provided.

Further, a crankcase temperature sensor 20 is fixed to the crankcase 2,
A throttle opening sensor 21 is connected to b, and an intake air temperature sensor 22 faces the air box 12.

(Structure of the continuously variable transmission) Reference numeral 23 in FIG. 3 denotes a well-known continuously variable transmission, and the continuously variable transmission 23 includes an input pulley 24, an output pulley 25, and both pulleys 2.
It is composed of a V-belt 23a continuously extending between 4, 25.

The input shaft 24a of the input pulley 24 is connected to the engine body 1
Are connected to the crankshaft 4. A fixed pulley 24b is fixed to the input shaft 24a.
A movable pulley 24c facing b is spline-engaged with the input shaft 24a so as to be movable in the axial direction.

Further, a weight retainer 24d is spline-engaged with the input shaft 24a on the rear side of the movable pulley 24c, and further,
Rotary shaft 24e supported by this weight retainer 24d
An end face of a fly weight 24f whose one end is pivotally supported by the movable pulley 24c is opposed to be able to press and contact. Further, a return sling 24h for pressing the weight retainer 24d toward the movable pulley 24c is interposed between the weight retainer 24d and a spring retainer 24g fixed to the shaft end of the input shaft 24a.

On the other hand, the output shaft 25a of the output pulley 25 is connected to an input shaft 25b connected to a crawler (not shown) provided at the rear of the snowmobile via a one-way clutch (not shown) for preventing reverse rotation. . A movable pulley 25d opposed to a fixed pulley 25c fixed to the output shaft 25a is spline-engaged with the output shaft 25a, and the movable pulley 25d is connected to the fixed pulley 25 via a return spring 25e.
It is constantly biased in the direction of 25c.

When the engine speed is equal to or lower than the set speed (for example, the clutch meet line is 3000 rpm to 4000 rpm), the centrifugal force acting on the flyweight 24f is weak, and as shown in FIG. The V-belt 23a interposed between the pulley 24b and the movable pulley 24c
The power transmission to the output pulley 25 side is interrupted by relatively sliding between b and 24c.

(Circuit Configuration of Control Unit) On the other hand, reference numeral 26 denotes a control unit (ECU) including a microcomputer, and the CPU (Central Processing Unit) 27,
The ROM 28, the RAM 29, the backup RAM 30, and the I / O interface 31 are connected to each other via a bus line 32, and a constant voltage circuit 33 is connected to them.

The constant voltage circuit 33 is connected in parallel with each other.
Relay contact of ECU relay 34 and self-shut relay 35
The battery 36 is connected via the relay contact of
The battery 36 supplies control power to each unit of the ECU 26 and also supplies backup power to the backup RAM 30.

Further, the ECU relay 34 has a pair of relay contacts,
Further, the electromagnetic coil 34a of the ECU relay 34 is connected to the battery via a kill switch 37 and an ignition switch 38.
Connected to 36. The ON terminals of the kill switch 37 and the ignition switch 38 are connected in series, and the OFF terminals are connected in parallel. As shown in the figure, when both switches 37 and 38 are in the ON position, the ECU relay 34 is turned on, and the control power is supplied to the constant voltage circuit 33 via one of the relay contacts.

When one of the kill switch 37 and the ignition switch 38 is OFF, the line from the CDI unit 39 serving as an ignition device is short-circuited, the ignition plug 13 is misfired, and the engine stops.

The kill switch 37 is an emergency stop switch provided on a grip of a snowmobile (not shown).

Also, the battery 36 has the self-shut relay
One end of the electromagnetic coil 35a, the injector 14, the one end of the electromagnetic coil 40a of the fuel pump relay 40, and the relay contact of the fuel pump relay 40 are connected to each other. The pump 19 is connected.

The self-shut relay 35 supplies power to the ECU 26 for a preset time (for example, 10 minutes) even after one of the kill switch 37 and the ignition switch 38 is turned off and the engine is stopped. Thus, after the engine is stopped, the start-time increase correction is not performed while the self-shut relay 35 is ON, thereby preventing the air-fuel ratio from becoming too rich at the time of hot restart.

The sensors 20, 21, 22 and the atmospheric pressure sensor 41 built in the ECU 26 are connected to input ports of the I / O interface 31 of the ECU 26.
Signal line for inputting CDI pulse from 9 and above
The other relay contact of the ECU relay 34 is connected.

Further, the input port of the I / O interface 31 has an idle adjusting resistor 42a provided in the idle adjusting means 42.
Are connected at one end. This idle adjusting means 42
For example, with a potentiometer, the idle adjustment means 42
By rotating the movable contact of the
The output voltage VMR of 42 is variably set, and the idle fuel injection pulse width is adjusted to take this output voltage VMR as a correction term.

Also, the input port of the I / O interface 31
A failure diagnostic mode switching connector 43 for switching the self-diagnostic function of the ECU 26 between a U-check mode (user use mode) and a D-check mode (Dura check mode).
And a failure diagnosis connector 44 are connected. When a failure occurs, a failure diagnosis is performed by connecting a vehicle diagnosis serial monitor 45 indicated by a two-dot chain line to the failure diagnosis connector 44. Do.

The failure diagnostic mode switching connector 43 is normally set in the U check mode, and when an abnormality occurs in the system, the trouble data is stored in the backup RA.
Stored and retained in M30.

At a dealer service station or the like, the serial monitor 45 is connected to the failure diagnosis connector 44, and the failure data is read to perform failure diagnosis. At this time, if the failure diagnostic mode switching connector 43 is switched to the D check mode, more detailed failure diagnosis can be performed.

The output ports of the I / O interface 31 have the other ends of the injector 14, the electromagnetic coil 40a of the fuel pump relay 40, and the electromagnetic coil 35a of the self-shut relay 35 via a drive circuit 46. It is connected.

In accordance with the control program stored in the ROM 28, the CPU 27 determines the engine speed N based on the CDI pulse interval.
The basic fuel injection pulse width Tp for the injector 14 is set based on the engine speed N and the throttle opening α detected by the throttle opening sensor 21, and further stored in the RAM 29. Based on various data, various corrections are applied to the basic fuel injection amount Tp to calculate a fuel injection pulse width Ti.

The CDI unit 39 is connected to the exciter coil 47a and the pulsar coil 47b of the magnet 47 driven by the crankshaft 4 of the engine body 1, and the primary side of the ignition coil 13a.
Thus, the spark plug 13 connected to the secondary side of the ignition coil 13a is sparked at predetermined timing.

Further, the magneto 47 includes a lamp coil 47c and a charge coil 47d.
7c is connected to an AC regulator 48, the AC output of which is controlled to a constant voltage, and supplied to an electric load 49 such as a lamp and a heater (not shown).
After the 47d AC output is full-wave rectified by the rectifier 50,
The battery 36 is charged.

(Functional Configuration of Control Device) As shown in FIG. 1, the function of calculating the fuel injection pulse width in the ECU 26 includes an engine speed calculating means 51, a basic fuel injection pulse width setting means 52, and various corrections for increasing the amount. It comprises coefficient setting means 53, injector voltage correction pulse width setting means 54, fuel injection pulse width setting means 55, and injector driving means 56.

The engine speed calculating means 51 calculates the engine speed N based on the CDI pulse output from the CDI unit 39.

That is, for example, in the case of a three-cylinder engine, the CD
Since the I pulse is output at every 120 ° C, from the elapsed time t120 ゜ between this CDI pulse Is calculated, and the engine speed N is calculated based on the cycle f (N = 60 / (2π · f)).

The basic fuel injection pulse width setting means 52 uses the engine speed N calculated by the engine speed calculating means 51 and the throttle opening (α) signal of the throttle opening sensor 21 as parameters to set the basic fuel injection pulse width map MP. The basic fuel injection pulse width TP is obtained directly from TP or by interpolation calculation.

Intake air amount Q passing through throttle valve 11b, engine speed N at that time, and throttle opening α
Have a certain functional relationship. The basic fuel injection pulse width TP is TP = K · Q / N when the air-fuel ratio is constant.
Can be obtained by Therefore, the basic fuel injection pulse width TP is determined by the engine speed N and the throttle opening α.
Can be obtained in advance from an experiment or the like as a parameter.

As shown in FIG. 4, the basic fuel injection pulse width map MP TP is a three-dimensional map using the throttle opening α and the engine speed N as parameters. The basic fuel injection pulse width Tp is stored.

By the way, the clutch meet line CL (for example, 3000 rpm to 4000 rpm) of the above-described continuously variable transmission 23 is substantially constant, and from the clutch meet line CL, the low engine speed side, that is, the no-load range A The basic fuel injection pulse width Tp in consideration of the acceleration increase correction value is stored in the increase area (for example, the area indicated by hatching) B in FIG. Further, the basic fuel injection pulse width Tp stored in the increase area B is set so as to increase stepwise as the throttle opening α and the engine speed N shift to a larger direction.

Further, the basic fuel injection pulse width Tp in the rapid deceleration region C on the engine speed N side higher than the clutch meet line CL.
Is set to “0”.

The various increase amount correction coefficient setting means 53 includes an atmospheric pressure sensor 41
Atmospheric pressure Po detected at, crankcase temperature TmC detected at crankcase temperature sensor 20, air-fuel ratio correction of air density required when setting air-fuel ratio based on intake temperature TmA detected at intake temperature sensor 22, That is, the correction coefficient COEF for various increments is set.

By the way, in the case of a two-cycle engine, the intake air is temporarily retained in the crank chamber 2a also serving as the preload chamber, so that it is easily affected by the warming and cooling of the crankcase 2. Therefore,
When setting a correction coefficient according to the density of the actual intake air supplied to the combustion chamber 7, the crankcase temperature TmC is required as a parameter in addition to the atmospheric pressure Po (altitude correction) and the intake temperature TmA.

The injector voltage correction pulse width setting means 54 reads the invalid injection pulse width of the injector 14 from a table (not shown) according to the terminal voltage VB of the battery 36, and sets the injector voltage correction pulse width TS for interpolating the invalid injection pulse width. I do.

In the fuel injection pulse width setting means 55, the basic fuel injection pulse width T set by the basic fuel injection pulse width setting means 52 is used.
P is multiplied by the various increase correction coefficients COEF set by the above various increase correction coefficient setting means 53, and this value (TP
× COEF) to add the injector voltage correction pulse width Ts set by the injector voltage correction pulse width setting means 54 to set the fuel injection pulse width Ti (Ti = TP × COEF + T
s).

Then, a drive pulse corresponding to the fuel injection pulse width Ti set by the fuel injection pulse width setting means 55 is output from the injector driving means 56 to the injector 14 at a predetermined timing.

By the way, even if the throttle valve 11b is suddenly opened from the fully closed state, the engine speed N does not change with the V belt 23 of the continuously variable transmission 23.
The throttle opening does not rise sharply due to the friction of a and the load applied to the output pulley 25, but first, the throttle opening greatly rises, as shown by a rapid acceleration line LACC shown by a dashed line in FIG. Then, the fuel injection pulse width Tp is increased when passing through each increasing area B of the no-load area A, and a sufficient driving force is output when the driving force is transmitted near the clutch meet line CL.

In addition, the rapid deceleration line LDEC when the throttle valve 11b is rapidly closed from the high-speed high-load operation (high engine speed state when the throttle valve is fully opened) is high for a while as shown by the two-dot chain line in FIG. After maintaining the rotation state, the engine speed N sharply decreases.

In the case of sudden acceleration at the start, clutch meat line C.
Thereafter, as the engine speed N increases, the continuously variable transmission 23
The running speed increases due to the change in the speed ratio of the vehicle. In rapid deceleration, the engine speed N decreases due to the change in the gear ratio caused by the decrease in output from the engine. Therefore, the fuel always passes through the rapid deceleration region C, and since the basic fuel injection pulse width Tp at this time is “0”, the fuel injected from the injector 14 is cut, and the effect of cleaning the inside of the crank chamber 2a is obtained.

During normal operation, the basic fuel injection pulse width TP stored in one of the areas surrounded by the rapid acceleration line LACC and the rapid deceleration line LDEC in the basic fuel injection pulse width map MPTP is set.

(Operation) Next, a fuel injection control procedure in the control device 26 having the above configuration will be described with reference to the flowchart of FIG. This fuel injection control is executed at every predetermined crank timing.

First, in step S101, the cycle f is obtained from the CDI pulse input interval (f = dt120 ゜ / dθ120 ゜), and the engine speed N is calculated based on this cycle f (N = 60 / 2π ・ f). Next, in step S102, the throttle opening α is read.

Then, in step S103, the basic fuel injection pulse width TP is obtained from the basic fuel injection pulse width map MP TP using the engine speed N calculated in step S101 and the throttle opening α read in step S102 as parameters. Is set directly or by interpolation calculation.

Then, in step S104, the crankcase temperature TmC,
The intake air temperature TmA and the atmospheric pressure Po are read, and step S10 is performed.
In step 5, various increment correction coefficients COEF are set based on each parameter.

At this time, the start acceleration increase and the fuel cut at the time of sudden deceleration are incorporated in the basic fuel injection pulse width Tp of the basic fuel injection pulse width map MPTP, and therefore, there is no need for calculation.

In step S106, the battery terminal voltage VB is read, and in step S107, the injector voltage correction pulse width Ts is set using the battery terminal voltage VB as a parameter.

Then, in step S108, the basic fuel injection pulse width TP set in step S103 and the
Various increase correction coefficients COE set respectively in 105 and S107
F, the fuel injection pulse width Ti is set based on the injector voltage correction pulse width Ts (Ti = TP × COEF + Ts).

Next, in step S109, a drive pulse corresponding to the fuel injection pulse width Ti set in step S108 is output to the injector 14 at a predetermined timing, and the routine is exited.

It should be noted that the present invention is not limited to the above-described embodiment. For example, the engine is not limited to a two-cycle engine, and can be applied to a four-cycle engine.

[Effects of the Invention] As described above, according to the present invention, the following effects can be obtained.

(1) Since the basic fuel injection pulse width stored in the vicinity of the no-load area of the clutch meet line in the basic fuel injection pulse width map is set to a value that takes into account the acceleration increase correction value, the acceleration increase correction at the start is performed. Sufficient acceleration performance can be obtained without any problem, and accordingly, arithmetic processing can be simplified and the load on the microcomputer can be reduced.

(2) Further, as set forth in claim 2, the basic fuel injection pulse width in consideration of the acceleration increase correction value is set so as to increase stepwise as the throttle opening and the engine speed shift to a larger direction. By doing so, the acceleration performance at the time of sudden start can be further improved.

[Brief description of the drawings]

1 is a functional block diagram of a fuel injection control device, FIG. 2 is an overall schematic diagram of an engine control system, FIG. 3 is a cross-sectional view of a continuously variable transmission, FIG. FIG. 5 is a conceptual diagram of a basic fuel injection pulse width map, and FIG. 5 is a flowchart showing a fuel injection control procedure. 23: continuously variable transmission, 52: basic fuel injection pulse width setting means, A: no load region, B: increasing amount region, CL: clutch meat line, MP TP: basic fuel injection pulse width map, N: engine speed, TP: basic fuel injection pulse width, α: throttle opening.

Continuation of the front page (72) Inventor Mitsugu Chonan 1-7-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Inside Fujishi Heavy Industries, Ltd. (56) References JP-A-63-29039 (JP, A) JP-A-1- 126438 (JP, A) JP-A-62-199934 (JP, A) JP-A-3-202653 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F02D 29/00-29 / 06 F02D 41/00-41/40 F02D 45/00 B60K 41/00-41/28

Claims (2)

(57) [Claims] 1. A fuel for an engine with a continuously variable transmission having basic fuel injection pulse width setting means for setting a basic fuel injection pulse width based on a basic fuel injection pulse width map using an engine speed and a throttle opening as parameters. In the injection control device, the basic fuel injection pulse width stored in the vicinity of the no-load region of the clutch meet line in the basic fuel injection pulse width map is set to a value that takes into account an acceleration increase correction value. A fuel injection control device for an engine with a transmission. 2. The apparatus according to claim 1, wherein the basic fuel injection pulse width in consideration of the acceleration increase correction value is set so as to increase stepwise as the throttle opening and the engine speed increase. 2. The fuel injection control device for an engine with a continuously variable transmission according to claim 1.