JP3824132B2 - Engine start control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an engine start control device that starts an engine by cranking it with a starter motor, and in particular, an engine start control device that improves startability by cranking a crankshaft in a reverse direction to a predetermined position after the engine is stopped. About.
[0002]
[Prior art]
In order to reduce the cranking torque when starting the engine and improve the startability of the engine, the crankshaft is reversely rotated back to a predetermined position before starting the engine, and the engine is started from the reverse position. A technique for improving the engine startability is disclosed in, for example, Japanese Patent Application Laid-Open No. 6-64451 or Japanese Patent Application Laid-Open No. 7-71350.
[0003]
[Problems to be solved by the invention]
In the above-described prior art, the crankshaft is reversed with a large cranking torque, so that the crankshaft is returned to just before reaching the compression top dead center that has passed during normal rotation. For this reason, when the reverse rotation energization to the drive (starter) motor is cut off, the crankshaft advances in the forward rotation direction due to the compression reaction force of the piston.
[0004]
Here, as in the above-described prior art, in the control method in which the crankshaft is reversely rotated at the time of engine start, and then forwardly rotated immediately thereafter, the compression reaction force and the forward driving force by the starter motor are simultaneously transmitted to the crankshaft. Even if the crankshaft advances in the forward rotation direction due to the compression reaction force, this does not impair the startability.
[0005]
On the other hand, in a system in which the crankshaft is reversely rotated to a predetermined position immediately after the engine is stopped rather than at the time of starting the engine to prepare for the next engine start, if the crankshaft advances in the forward rotation direction due to the compression reaction force of the piston. When the next engine is started, the running distance is shortened, so that a desired inertia force cannot be obtained, and the engine startability cannot be sufficiently improved.
[0006]
The object of the present invention is to solve the above-described problems of the prior art and to sufficiently improve the startability of the engine in reverse rotation control in preparation for the next engine start by reversing the crankshaft to a predetermined position immediately after the engine stops. Is to make it.
[0007]
[Means for Solving the Problems]
In order to achieve the above-described object, the present invention provides a starter motor that forwardly and reversely rotates a crankshaft in an engine start control device that reversely rotates the crankshaft to a predetermined position after the engine stops to prepare for the next engine start. Reverse rotation control means for starting reverse rotation energization to the starter motor after engine stop, crank angle detection means for detecting that the reverse crankshaft has reached the top dead center equivalent angle of the piston, and reverse rotation load of the crankshaft The reverse rotation control means detects that the crank angle detection means has detected that the crankshaft has reached the top dead center equivalent angle and that the reverse load detection means has detected an increase in the reverse load. The reverse rotation energization is terminated in response to whichever is earlier.
[0008]
According to the above feature, when the crankshaft reaches the top dead center equivalent angle before the reverse rotation load of the crankshaft increases, the position is predicted to be near the exhaust top dead center. Therefore, if reverse energization is stopped at this position, the crankshaft can be further reversely rotated by inertial force and returned to the position before the compression top dead center (during reverse rotation).
[0009]
On the other hand, if the reverse rotation load of the crankshaft rises before the crankshaft reaches the top dead center equivalent angle, the position is already in front of the compression top dead center (during reverse rotation). The crankshaft can be stopped before the compression top dead center (at the time of reverse rotation) at a position where the compression reaction force is small.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is an overall side view of a scooter type motorcycle to which a vehicle power generation control device of the present invention is applied.
[0011]
The front part of the vehicle body and the rear part of the vehicle body are connected via a lower floor part 4, and the vehicle body frame forming the skeleton of the vehicle body is generally composed of a down tube 6 and a main pipe 7. The fuel tank and the storage box (both not shown) are supported by the main pipe 7, and the seat 8 is disposed above the fuel tank and the storage box.
[0012]
At the front of the vehicle body, a handle 11 is provided on the upper side of the steering head 5 so as to be pivoted, a front fork 12 extends downward, and a front wheel FW is pivotally supported on the lower end thereof. The upper part of the handle 11 is covered with a handle cover 13 that also serves as an instrument panel. A bracket 15 protrudes from the lower end of the rising portion of the main pipe 7, and a hanger bracket 18 of the swing unit 2 is connected to the bracket 15 through a link member 16 so as to be swingable.
[0013]
The swing unit 2 is equipped with a single-cylinder four-cycle engine E at the front thereof. A belt type continuously variable transmission 10 is configured from the engine E to the rear, and a rear wheel RW is pivotally supported by a speed reduction mechanism 9 provided at a rear portion thereof via a centrifugal clutch. A rear cushion 3 is interposed between the upper end of the speed reduction mechanism 9 and the upper bent portion of the main pipe 7. In front of the swing unit 2, a carburetor 17 connected to an intake pipe 19 extending from the engine E and an air cleaner 14 coupled to the carburetor 17 are disposed.
[0014]
FIG. 2 is a cross-sectional view of the swing unit 2 cut along the crankshaft 201. The same reference numerals as those described above represent the same or equivalent parts.
[0015]
The swing unit 2 is covered with a crankcase 202 configured by combining left and right crankcases 202L and 202R, and the crankshaft 201 is rotatably supported by bearings 208 and 209 fixed to the crankcase 202R. . A connecting rod (not shown) is connected to the crankshaft 201 via a crankpin 213.
[0016]
The left crankcase 202L also serves as a belt type continuously variable transmission chamber case, and a belt drive pulley 210 is rotatably provided on the crankshaft 201 extending to the left crankcase 202L. The belt driving pulley 210 includes a fixed pulley half 210L and a movable pulley half 210R. The fixed pulley half 210L is fixed to the left end portion of the crankshaft 201 via a boss 211, and a movable side on the right side thereof. The pulley half body 210R is spline-fitted to the crankshaft 201 and can approach and separate from the stationary pulley half body 210L. A V-belt 212 is wound between the pulley halves 210L and 210R.
[0017]
A cam plate 215 is fixed to the crankshaft 201 on the right side of the movable pulley half 210R, and a slide plate 215a provided on the outer peripheral end of the movable pulley half 210R is formed in the axial direction at the outer peripheral end of the movable pulley half 210R. The sliding boss portion 210Ra is slidably engaged. The cam plate 215 of the movable pulley half 210R has a tapered surface whose outer periphery is inclined toward the cam plate 215, and a dry weight pole 216 is formed in a space between the tapered surface and the movable pulley half 210R. Is housed.
[0018]
When the rotational speed of the crankshaft 201 increases, the dry weight ball 216 that rotates between the movable pulley half 210R and the cam plate 215 and rotates together moves in the centrifugal direction by centrifugal force, and the movable pulley half 210R It is pressed by the dry weight ball 216 and moves to the left to approach the fixed pulley half 210L. As a result, the V-belt 212 sandwiched between the pulley halves 210L and 210R moves in the centrifugal direction, and the winding diameter increases.
[0019]
A driven pulley (not shown) corresponding to the belt driving pulley 210 is provided at the rear of the vehicle, and the V-belt 212 is wound around this driven pulley. By this belt transmission mechanism, the power of the engine E is automatically adjusted and transmitted to the centrifugal clutch, and the rear wheel RW is driven via the speed reduction mechanism 9 and the like.
[0020]
A starter / generator 1 in which a starter motor and an AC generator are combined is disposed in the right crankcase 202R. In the starter / generator 1, the outer rotor 60 is fixed to the tip tapered portion of the crankshaft 201 with screws 253. The inner stator 50 disposed inside the outer rotor 60 is supported by being screwed to the crankcase 202 with bolts 279.
[0021]
The fan 280 is fixed to the outer rotor 60 with a bolt 246 at the bottom of the central conical portion 280a. The fan 280 is covered with a fan cover 281 via a radiator 282.
[0022]
A sprocket 231 is fixed on the crankshaft 201 between the starter / generator 1 and the bearing 209, and a chain for driving a camshaft (not shown) from the crankshaft 201 is attached to the sprocket 231. It is wrapped around. The sprocket 231 is formed integrally with a gear 232 for transmitting power to a pump for circulating lubricating oil.
[0023]
FIG. 3 is a block diagram of a control system of the starter / generator 1, and the same reference numerals as those described above represent the same or equivalent parts.
[0024]
The ECU includes a three-phase full-wave rectification bridge circuit 400 for full-wave rectification of the three-phase alternating current generated by the generator function of the starter / generator 1, and an output of the full-wave rectification bridge circuit 400 with a predetermined regulated voltage (regulator operating voltage). : For example, 14.5V) and a swing back control unit 700 that reversely rotates the crankshaft 201 to a predetermined position after the engine is stopped.
[0025]
The ECU is connected to a rotor angle sensor 29, an ignition coil 21, a throttle sensor 23, a fuel sensor 24, a seat switch 25, an idle switch 26, a cooling water temperature sensor 27, and an ignition pulser 30, and detection signals are input to the ECU. The A spark plug 22 is connected to the secondary side of the ignition coil 21.
[0026]
Further, a starter relay 34, a starter switch 35, stop switches 36 and 37, a standby indicator 38, a fuel indicator 39, a speed sensor 40, a motorcycle star 41, and a headlight 42 are connected to the ECU. The headlight 42 is provided with a dimmer switch 43.
[0027]
A current is supplied from the battery 46 to each of the above parts via the main fuse 44 and the main switch 45. The battery 46 has a circuit that is directly connected to the ECU by the starter relay 34 and connected to the ECU only through the main fuse 44 without passing through the main switch 45.
[0028]
FIG. 4 is a diagram showing a configuration of a main part related to the swing back control of the ECU, and the three-phase full-wave rectification bridge circuit 400 is configured by connecting three sets of two FETs connected in series in parallel. The
[0029]
In swing back control unit 700, stage determination unit 73 divides one rotation of crankshaft 201 into 36 stages of stages # 0 to # 35 based on the output signal of rotor angle sensor 29, and a pulse generated by ignition pulser 30. The current stage is determined using the signal detection timing as the reference stage (stage # 0).
[0030]
The stage passage time detection unit 74 detects the passage time Δtn of the stage based on the time from when the stage determination unit 73 determines a new stage until the next stage is determined. The reverse rotation control unit 75 generates a reverse rotation drive command based on the determination result by the stage determination unit 73 and the passage time Δtn detected by the stage passage time detection unit 74.
[0031]
The duty ratio setting unit 72 dynamically controls the duty ratio of the gate voltage supplied to each power FET of the full-wave rectification bridge circuit 400 based on the determination result by the stage determination unit 73. The driver 71 supplies the drive pulse having the set duty ratio to each power FET of the full-wave rectification bridge circuit 400.
[0032]
Next, the operation of the swing back control unit 700 will be described with reference to the flowchart of FIG. 5 and the operation explanatory diagram of FIG. FIG. 6 (a) shows the relationship between the cranking torque (reverse rotation load) required to reverse the crankshaft 201 and the crank angle. The cranking torque is just before reaching the compression top dead center (during reverse rotation). It rises rapidly. FIG. 4B shows the relationship between the crank angle and the stage, and FIG. 4C shows the change in the angular velocity of the crankshaft during reverse rotation.
[0033]
When engine stop is detected in step S11, in steps S12 and S13, the current stage already determined by the stage determination unit 73 is referred to. Here, if the current stage is any of stages # 0 to # 11, the process proceeds to step S14. If any of the stages # 12 to # 32, the process proceeds to step S15, and otherwise (that is, stages # 33 to ##). 35), the process proceeds to step S16. In steps S14 and S16, the duty ratio setting unit 77 sets the duty ratio of the drive pulse to 70%, and in step S15, the duty ratio is set to 80%.
[0034]
Such dynamic control of the duty ratio sufficiently lowers the angular velocity of the crankshaft 201 at the time of reverse rotation just before the compression top dead center equivalent angle (at the time of reverse rotation) at which cranking torque increases, as will be described in detail later. At the same time, it is performed in order to enable quick reverse drive at other angles.
[0035]
In step S17, the driver 71 controls each power FET of the full-wave rectification bridge circuit 400 with the set duty ratio to start reverse energization. In step S18, the energization time Δtn of the stage #n that has passed is measured by the stage passage time detector 74.
[0036]
In step S19, the reverse rotation control unit 75 determines whether or not the crankshaft 201 has passed through stage # 0, that is, near the top dead center. If the stage # 0 has not been passed, in step S21, the ratio of the passing time Δtn of the stage #n that passed immediately before and the passing time Δtn-1 of the stage # (n−1) that passed before [ [Delta] tn / [Delta] tn-1] is compared with a reference value Rref (4/3 in this embodiment). If the passing time ratio [Δtn / Δtn-1] does not exceed the reference value Rref, the process returns to step S12 to engage reverse rotation, and the above-described processes are repeated in parallel with this.
[0037]
Here, as shown by the curve A in FIG. 6 (c), the engine stop position, that is, the reverse rotation start position is closer to the next compression top dead center than the intermediate position between the previous and next compression top dead centers. Thus, in the process from passing through the exhaust top dead center (during forward rotation) to compression top dead center, the crank is applied even though the starter / generator 1 is driven in reverse at a duty ratio of 70%. The shaft can pass through stage # 0 (exhaust top dead center). Therefore, this is detected in step S19, and the process proceeds to step S20 to determine whether or not the crankshaft 201 has reached stage # 32. If it is determined that the crankshaft 201 has reached stage # 32, the reverse energization is stopped in step S22, and then the crankshaft is further rotated in the reverse direction by the inertial force and then stopped.
[0038]
On the other hand, as shown by curve B in FIG. 6 (c), the reverse rotation start position is closer to the previous compression top dead center than the intermediate position between the previous and next compression top dead centers, in other words, compression up In the process from passing through the dead center (during forward rotation) to exhaust top dead center, the starter / generator 1 is driven in reverse at a duty ratio of 70%, so the reverse load is shown in FIG. As shown in FIG. 6, when the angle rises before reaching stage # 0 (at the time of reverse rotation), the angular velocity of the crankshaft 201 rapidly decreases. If it is determined in step S21 that the passing time ratio [Δtn / Δtn-1] is 4/3 or more of the reference value, the reverse energization is stopped in step S22, and the reverse rotation of the crankshaft is stopped. Stops almost simultaneously.
[0039]
As described above, in this embodiment, during reverse rotation driving after the engine is stopped, it is monitored whether the crankshaft has passed the top dead center equivalent angle and whether the crankshaft angular velocity has decreased, and the crankshaft is reversely rotated. Sometimes when the top dead center is passed, the reverse rotation energization ends immediately, and the reverse rotation energization also ends when the angular velocity of the crankshaft decreases due to the increase in reverse load. It can be returned to a position before compression top dead center (at the time of reverse rotation) and a low compression reaction force.
[0040]
Furthermore, in the present embodiment, the angular velocity of the crankshaft 201 is detected based on the output of the rotor angle sensor 29 that detects the rotor angle (that is, the stage) of the starter / generator 1. There is no need to provide a separate sensor for detection.
[0041]
【The invention's effect】
According to the present invention, the following effects are achieved.
[0042]
(1) If the arrival at the crankshaft top dead center equivalent angle is detected before the crankshaft reverse load increase is detected, the position can be predicted to be near the exhaust top dead center. By stopping the reverse energization, the crankshaft can be further returned to a desired position by inertial force.
[0043]
Further, if an increase in the reverse rotation load of the crankshaft is detected before the arrival at the top dead center equivalent angle of the crankshaft is detected, the position is in front of the compression top dead center (during reverse rotation). Since the compression reaction force is at a low position, the crankshaft can be stopped at a position where the compression reaction force is low by stopping the reverse energization here.
[0044]
(2) Since the reverse rotation driving torque of the starter motor is reduced at the top dead center and in the vicinity thereof, the angular speed of the reverse crankshaft can be reduced before the compression top dead center. Therefore, it is possible not only to prevent the crankshaft from exceeding the compression top dead center equivalent angle, but also to easily detect that the crankshaft has reached the compression top dead center.
[0045]
(3) When the crankshaft passes the top dead center during reverse rotation, the reverse rotation energization is stopped immediately thereafter, and then the crankshaft is further reversed using the inertial force, thus shortening the energization time to the starter motor. And power consumption can be reduced.
[0046]
(4) Since the angular velocity of the crankshaft is detected based on the output of the sensor that detects the rotor angle of the starter motor, it is not necessary to separately provide a sensor for detecting the angle of the crankshaft 201.
[Brief description of the drawings]
FIG. 1 is an overall side view of a scooter type motorcycle to which the present invention is applied.
FIG. 2 is a cross-sectional view taken along the crankshaft of the swing unit of FIG.
FIG. 3 is a block diagram of a control system of a starter / generator.
4 is a block diagram showing a configuration of a main part of the ECU of FIG. 3;
FIG. 5 is a flowchart of swingback control.
FIG. 6 is an operation explanatory diagram of swingback control.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Starter and generator, 2 ... Swing unit, 30 ... Ignition pulser, 100 ... Regulator, 201 ... Crankshaft, 400 ... Three-phase full-wave rectification bridge circuit, 700 ... Swingback control part

Claims (5)

In the engine start control device for preparing for the next engine start by reversing the crankshaft to a predetermined position after the engine stops,
A starter motor for forward and reverse rotation of the crankshaft;
Reverse rotation control means for starting reverse rotation energization to the starter motor after the engine is stopped;
Crank angle detection means for detecting that the reverse crankshaft has reached the top dead center equivalent angle of the piston;
A reverse load detecting means for detecting the reverse load of the crankshaft,
The reverse rotation control means includes
In response to the earlier one of the crank angle detection means detecting the arrival of the crankshaft at the top dead center equivalent angle and the reverse load detection means detecting an increase in the reverse rotation load, whichever is earlier An engine start control device characterized by terminating reverse energization. The drive torque when reversing the starter motor is reduced during the passage of the crankshaft through the top dead center equivalent angle and the vicinity thereof than during the passage of the crankshaft through other angular regions. The engine start control device according to claim 1. 2. The engine start control device according to claim 1, wherein the reverse load detecting means detects the reverse load based on a change in angular velocity of the crankshaft that rotates in reverse. The starter motor includes rotation angle detection means for detecting the rotation angle,
4. The engine start control device according to claim 3, wherein the reverse load detecting means represents a change in angular speed of the crankshaft by a change in angular speed of the starter motor detected by the rotation angle detecting means. 5. The engine start control device according to claim 1, wherein the engine is a four-cycle engine, and the crank angle detection means is an ignition pulser that detects an ignition timing.

Images