JP5995894B2 - Ignition control device for vehicle engine - Google Patents

Description

  The present invention relates to an ignition control device for a vehicle engine, and more particularly to an ignition control device for a vehicle engine that determines an ignition timing by switching two ignition timing maps with each other.

  Conventionally, an ignition control device for a vehicle engine that has two ignition timing tables of an advance angle (advance angle side) and a delay angle side (retard angle side) and switches the ignition timing table according to the engine load. It has been known.

  In Patent Document 1, a scooter type motorcycle having a V-belt type power transmission device (continuously variable transmission) and a centrifugal clutch in a drive system has two ignition timing tables on the advance side and the retard side. During normal operation, the ignition timing table is switched according to the engine load. On the other hand, until the vehicle speed reaches a predetermined value after the centrifugal clutch is connected, the advance side table is used regardless of the engine load. A control technique for improving the above is disclosed.

JP 2002-285944 A

  However, in the technique described in Patent Document 1, since the advance side table is used up to a predetermined vehicle speed after the centrifugal clutch is connected, knocking is not performed when the centrifugal clutch is connected and the driving state is low and high. Could occur. Further, in the configuration in which the engine load is estimated and detected based on the fluctuation amount Δω of the rotational speed (angular speed ω) in one cycle of the crankshaft, the angular speed ω is changed by the shifting operation of the continuously variable transmission and the connecting / disconnecting operation of the centrifugal clutch. When the fluctuation amount Δω changes and the detection accuracy of the engine load decreases, there is a problem that it is difficult to appropriately switch the ignition timing table.

  An object of the present invention is to solve the above-described problems of the prior art and provide an ignition control device for a vehicle engine that can appropriately switch an ignition timing control table while preventing occurrence of knocking.

  In order to achieve the above object, the present invention provides an ignition control device for a vehicle engine having a belt-type transmission (TM) and a centrifugal clutch (CL) in a drive system. Engine load factor estimating means (30) for estimating the load factor (LR) of the engine (E) based on the fluctuation amount (Δω) of the crank angular velocity (ω1, ω2) of the engine, and according to the load factor (LR) Ignition timing calculation means (60) for calculating the ignition timing of the engine (E), centrifugal clutch connection state determination means (40) for determining the connection state of the centrifugal clutch (CL), and the centrifugal clutch (CL) Is determined to be in an unconnected state, and includes ignition timing correction means (52) for correcting the ignition timing to the advance side regardless of the ignition timing according to the load factor (LR). Feature 1 A.

  The ignition timing calculating means (60) calculates an ignition timing based on the advance side table (61) or the retard side table (62) selected according to the load factor (LR), and the ignition timing is calculated. When the centrifugal clutch (CL) is determined to be in an unconnected state, the timing correction means (52) is a case where the retard side table (62) is selected according to the load factor (LR). The second feature is that the ignition timing is corrected to the advance side by applying the advance side table (61).

  The centrifugal clutch connection state determining means (40) has a third feature in that the connection state of the centrifugal clutch (CL) is determined based on the load factor (LR) and the engine speed (Ne). .

  The ignition timing calculation means (60) is based on a Ne-LR map (51) preliminarily defining a relationship among the load factor (LR), the engine speed (Ne), and the application range of the ignition timing table. The ignition timing is calculated by applying either the advance side table (61) or the retard side table (62). The Ne-LR map (51) includes the advance side table (61). ) And an application range of the retard side table (62) have a fourth feature in that a hysteresis region (H) is set.

Further, the hysteresis region (H) indicates a high-side threshold value (LR_Hi) indicating a boundary on the application range side of the advance angle side table (61) and a boundary on the application range side of the retard angle side table (62). It is set as an area surrounded by the low threshold (LR_Low)
The ignition timing calculation means (60) indicates that the operating state of the engine (E) represented by the engine speed (Ne) and the load factor (LR) on the Ne-LR map (51) The transition condition from the application range of the retard angle side table (62) to the low threshold value when transitioning from the application range of the table (61) to the retard angle side table (61) when crossing the boundary line by the high threshold value (LR_Hi) There is a fifth feature in that it is configured so as to be more relaxed than the transition condition to the advance side table (61) when crossing the boundary line by (LR_Low).

  According to the first feature, the engine load factor estimating means for estimating the load factor of the engine based on the fluctuation amount of the crank angular speed of the crankshaft of the engine, and the ignition timing calculation for calculating the ignition timing of the engine according to the load factor Means, a centrifugal clutch engagement state determination means for determining the connection state of the centrifugal clutch, and if it is determined that the centrifugal clutch is in an unconnected state, the ignition timing is set to the advance side regardless of the ignition timing according to the load factor. The ignition timing correction means for correcting the engine timing is high, so that the engine load factor is high, and even if the retarded side is selected in the normal ignition timing determination, until the centrifugal clutch is connected, The ignition timing on the advance side can be applied. This improves fuel efficiency while avoiding knocking in the low rotation and low load range corresponding to low-speed cruise driving, and avoids knocking by applying the ignition timing according to the engine load immediately after the centrifugal clutch is connected. It becomes possible to do.

  In addition, when detecting the fluctuation amount of the crank angular velocity based on the time measured by the crank pulse and the timer, it is not necessary to use a special sensor in addition to the crank pulse generator and the timer, and the V belt type continuously variable A scooter-type vehicle equipped with a transmission and a centrifugal clutch is suitable for a simple configuration without adding an intake negative pressure sensor, knock sensor, etc. It is possible to obtain the ignition timing.

  According to the second feature, the ignition timing calculation means calculates the ignition timing based on the advance side table or the retard side table selected according to the load factor, and the ignition timing correction means has the centrifugal clutch not yet installed. When the connection state is determined, the ignition timing is corrected to the advance side by applying the advance side table even when the retard side table is selected according to the load factor. By simply correcting the selection of the two ignition timing tables according to the connection state, it is possible to obtain an appropriate ignition timing without increasing the calculation load.

  According to the third feature, since the centrifugal clutch engagement state determination means determines the connection state of the centrifugal clutch based on the load factor and the engine speed, a sensor that detects the rotational speeds of the input side and the output side of the centrifugal clutch. It is possible to determine the connection state of the centrifugal clutch with a simple configuration without using the above.

  According to the fourth feature, the ignition timing calculating means is based on the advance side table or the retard side based on the Ne-LR map that predefines the relationship among the load factor, the engine speed, and the application range of the ignition timing table. The ignition timing is calculated by applying one of the tables, and in the Ne-LR map, a hysteresis region is set between the application range of the advance side table and the application range of the retard side table. Therefore, it is possible to prevent the ignition timing table from being frequently switched according to a change in the engine load factor due to the road surface state represented by the wavy road. As a result, unnecessary torque fluctuation due to switching of the ignition timing table can be suppressed and high-quality driving feeling can be maintained.

  According to the fifth feature, the hysteresis region is surrounded by a high-side threshold value indicating a boundary on the application range side of the advance angle side table and a low-side threshold value indicating a boundary on the application range side of the retard angle side table. In the Ne-LR map, the ignition timing calculation means indicates that the engine operating state represented by the engine speed and the load factor shows a boundary line based on the high side threshold from the application range of the advance side table. Since the transition condition to the retard side table when straddling is configured to be more relaxed than the transition condition to the advance side table when straddling the boundary line by the low threshold from the applicable range of the retard side table. On the road surface represented by the wavy road, which greatly affects the fluctuation amount of the crank angular speed, it is difficult to switch the ignition timing table even if a hysteresis region is provided in the Ne-LR map. In such a case, the switching from the advance side to the retard side is performed early (a short predetermined time) to execute the control with the highest priority on preventing knocking, while the control from the retard side to the advance side is performed. Strict switching conditions can prevent hunting.

It is sectional drawing of the power unit in which the ignition timing control apparatus of the vehicle engine which concerns on one Embodiment of this invention is used. It is a front view of a generator. It is explanatory drawing which shows the calculation method of fluctuation amount (DELTA) omega of crank angular velocity. It is a block diagram which shows the structure of a control part. It is a flowchart which shows the procedure of ignition timing determination control. It is a Ne-LR map contained in an ignition timing table determination means. It is a subflow which shows the procedure of a centrifugal clutch connection state determination process. It is a flowchart which shows the procedure of the control which transfers an ignition timing table. It is a time chart which shows the flow of control which transfers an ignition timing table.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view of a transmission-integrated power unit P in which an ignition timing control device for a vehicle engine according to an embodiment of the present invention is used. The power unit P is a swing arm unit mainly used in a scooter type motorcycle, and is formed by integrally forming a four-cycle single-cylinder engine E and a V-belt type continuously variable transmission TM. The continuously variable transmission TM is housed inside a cantilever arm portion 43 that supports drive wheels (not shown).

  In the cylinder 32 of the engine E, the piston 24 connected to the connecting rod 33 is slidably accommodated. The other end of the connecting rod 33 is pivotally supported with respect to the crankshaft 1. A cylinder head 25 is fixed to the upper part of the cylinder 32, and a combustion chamber 23 is formed between the cylinder head 25 and the piston 24. An electrode portion of a spark plug 16 as an ignition device protrudes from the ceiling surface of the combustion chamber 23.

  A camshaft 18 that drives an intake / exhaust valve is housed in the internal space of the cylinder head 25 covered with the cylinder head cover 17. The camshaft 18 is driven to rotate by a driving force transmitted from the sprocket portion 45 provided on the crankshaft 1 via the endless cam chain 22 and the cam sprocket 19.

  An outer rotor type AC generator (generator) G is provided at the right end of the crankshaft 1 that is rotatably supported by the crankcase 42. The generator G includes a bottomed cylindrical rotor 3 that rotates synchronously with a crankshaft, and a stator 2 that is fixed to a crankcase cover 42a of the crankcase 42. The outer peripheral surface of the rotor 3 is provided with a reluctator 4 having a predetermined length in the circumferential direction, and a crank pulse is generated by detecting the passing state of the reluctator 4 with the pickup coil 5.

  A driving pulley 36 of the continuously variable transmission TM is attached to the left end of the crankshaft 1 in the figure. The driving pulley 36 includes a fixed half body 38 fixed to the crankshaft 1 and a movable half body 37 slidable in the axial direction in order to change the winding diameter of the belt V. In the present embodiment, the movable half body 37 is configured to be driven by a transmission motor 28 as an actuator, and the positions near the high speed and the low speed are indicated by (H) and (L), respectively. The rotational power of the transmission motor 28 is transmitted from the pinion gear 27 fixed to the rotating shaft to the screw mechanism that slides the movable half body 37 via the intermediate gears 26 and 34. The sliding amount of the movable half body 37 is detected by the transmission ratio sensor 35.

  The driving force transmitted to the belt V is transmitted to a driven pulley 55 composed of a fixed half 47 and a movable half 54. The movable half 54 constituting the driven pulley 55 is constantly urged toward the fixed half 47 by the coil spring 48. When the winding diameter of the driving pulley 36 is increased, the driving pulley 36 slides away from the fixed half 47 against the biasing force of the coil spring 48, and the winding diameter of the driven pulley 55 is relatively decreased. . This figure shows a state (H) in which the movable half 54 is in a gear ratio close to a high speed and a state (L) in a gear ratio close to a low speed.

  As described above, the driving force is transmitted by the friction force between the driving pulley 36 and the driven pulley 55 and the V belt, and the transmission ratio is changed by changing the winding diameter of each pulley. In the continuously variable transmission, a slight slip occurs between the pulley and the belt at the time of shifting. And the fluctuation | variation of the driving force by this slip will be transmitted to a driving wheel side, and will also affect the rotation state of the crankshaft 1 by the reaction from a road surface.

  The driving force transmitted to the driven pulley 55 is transmitted to the output shaft 44 via the centrifugal clutch CL. The movable half 54 is attached to the cylindrical shaft 49 so as to be slidable in the axial direction and not rotatable in the circumferential direction. The left end of the cylindrical shaft 49 is fixed to a disc-shaped clutch plate that supports the clutch shoe 53. In the centrifugal clutch CL, when the rotational speed of the driven pulley 55 increases, the centrifugal weight pushes the clutch shoe 53 radially outward, and a frictional force is generated between the clutch shoe 53 and the inner peripheral wall of the clutch outer 52. Switch to connected state with. When the centrifugal clutch CL is in the connected state, the driving force transmitted to the clutch outer 52 is output from the output shaft 44 to the axle 46 of the driving wheel via the speed reduction mechanism.

  In the present embodiment, the winding diameter of the driving pulley 36 is automatically changed by the speed change motor 28 in accordance with a speed change map determined by experiments or the like in relation to the engine speed Ne, the vehicle speed, and the speed change ratio. The structure may be such that the speed change motor 28 is not provided, and the speed change ratio is automatically changed according to the engine speed Ne.

  FIG. 2 is a front view of the generator G. FIG. As described above, on the outer peripheral portion of the outer rotor 3, the single reluctator 4 is disposed in the range of the angle θ in the circumferential direction. The pickup coil 5 detects the start of passage of the reluctator 4 at the rising edge of the pulse signal and detects the end of passage of the reluctor 4 at the falling edge of the pulse signal. The pulse signal generated in this way is output as a crank pulse to the control unit 10 (see FIG. 4).

  FIG. 3 is an explanatory diagram showing a method of calculating the variation amount Δω of the crank angular speed based on the crank pulse signal. The ignition control device for a vehicle engine according to the present embodiment calculates a load factor LR (see FIG. 4) as an engine load based on the crank angular velocity fluctuation amount Δω, and two types of ignition are performed according to the load factor LR. The ignition timing is calculated using the selected ignition timing table by switching the timing table, that is, the ignition timing table closer to the advance or retard.

  Here, the crank angular speed ω of the crankshaft 1 varies periodically in accordance with one cycle of the engine, that is, four strokes of compression, expansion, exhaust, and intake, even when the average value of the engine rotational speed Ne is constant. Is repeated. Specifically, in the compression stroke, the crank angular speed ω is reduced due to the compression resistance due to the increase in the cylinder internal pressure. Further, in the section of the expansion stroke, crank rotational energy is generated by an increase in the cylinder internal pressure due to combustion, and an increase resulting from this is generated. The crank angular speed ω reaches a peak just before the end of the expansion stroke, and then decreases due to pump work such as mechanical friction resistance in the engine, discharge resistance of burned gas in the exhaust stroke, and suction resistance in the intake stroke. Subsequently, the fluctuation of reaching the intake / compression stroke again is repeated.

  The fluctuation peak of the crank angular speed ω increases in accordance with the generated torque of the engine, and the subsequent decrease amount increases as the intake air amount increases. Therefore, the variation in the crank angular speed ω increases as the engine has a larger generated torque and a larger intake air amount. Furthermore, this variation becomes larger as the inertial force of the crankshaft is smaller in the low rotation range, and becomes larger as the number of cylinders is smaller and the explosion interval is larger. Therefore, in an engine having a relatively small crankshaft moment of inertia, such as a single-cylinder engine of a motorcycle, variation in the crank angular speed ω tends to be large.

  FIG. 3 shows a correspondence relationship between the crank angular speed waveform when the engine rotational speed Ne is about 3000 rpm, the reluctator position and the reluctator pulse. The relaxer 4 is located near the end of the compression stroke near the top dead center, and generates two pulses, a rising pulse P1 and a falling pulse P2. Here, if the phase angle of the reluctator 4 is θ and the time for which the reluctator 4 moves during engine rotation is τ, the angular velocities ω1 and ω2 of the reluctator 4 can be calculated by the equation θ ÷ τ. In this embodiment, the difference (ω2−ω1) between the angular velocities ω2 and ω1 is used as the variation amount Δω of the crank angular velocity.

  In general, engine knocking countermeasures are implemented by applying a retarded ignition timing in a low rotation range where knocking is likely to occur. On the other hand, fuel consumption is reduced at low rotation and low load in the low speed cruise region. In order to improve, there is also a demand to apply an ignition timing close to the advance angle in the low rotation range. Furthermore, when accelerating by gradually opening the throttle from a low vehicle speed, it is preferable to apply an ignition timing table closer to the advance angle even after the centrifugal clutch is connected. For this reason, it is necessary to select the ignition timing more precisely in the lower rotation range. That is, when the ignition timing is determined based on the engine load, it can be said that the engine load is required to be detected with high accuracy in the low rotation and low vehicle speed range.

  However, a scooter vehicle using a V-belt type continuously variable transmission and a centrifugal clutch has a problem in that a reduction in detection accuracy of the engine load factor is unavoidable in a low rotation and low vehicle speed range due to its structure.

  This is because, as described above, the crank fluctuation torque attenuated at the friction transmission portion between the belt and pulley of the continuously variable transmission changes according to the reduction ratio fluctuation of the transmission. If there is such a change, the change of the fluctuation amount Δω becomes large even if the engine speed and the output torque are the same. Furthermore, the change in the amount of fluctuation Δω is also increased when the torque transmission state changes due to the connected state of the centrifugal clutch. The present invention is intended to optimize the selection of the ignition timing table without introducing a special sensor or the like in consideration of such a change in the fluctuation amount Δω that is unavoidable due to the structure of the scooter type vehicle.

  FIG. 4 is a block diagram showing the configuration of the control unit 10 that constitutes the ignition timing control device for a vehicle engine according to the present embodiment. FIG. 5 is a flowchart showing the procedure of ignition timing determination control. The control unit 10 only inputs a crank pulse signal from the outside, and the other is based on a plurality of data maps / data tables predetermined by experiments or the like. ) Or retarded side (table 2), and the optimum ignition timing is determined from the selected ignition timing table. The present embodiment is characterized in that it has means for correcting the selection of the ignition timing table, paying attention to the fact that it is preferable to use the advance side table 1 in a state before the centrifugal clutch CL is connected.

  Hereinafter, the configuration of the block diagram of FIG. 4 will be described with reference to the procedure shown in the flowchart of FIG. The crank pulse output from the pickup coil 5 is input to the crank pulse input unit 11 of the control unit 10. The engine speed calculation means 13 calculates the engine speed Ne based on the crank pulse information and the predetermined time measured by the timer 12 (corresponding to step S1 in FIG. 5).

The Δω calculating means 14 calculates the crank angular speed variation Δω by the calculation method described with reference to FIG. 2 (corresponding to step S2 in FIG. 5). Further, the Δω _WOT calculating means 20 is based on a Ne-Δω _WOT map 21 determined in advance by experiments or the like, so that the throttle opening is fully opened (WOT: wide open throttle) with respect to the current engine speed Ne. If so, the fluctuation amount Δω _WOT of the angular velocity is derived (corresponding to step S3 in FIG. 5). The fluctuation amount Δω _WOT is a value that gradually decreases as the engine speed Ne increases.

The engine load factor estimator 30 calculates the engine load factor LR (%) by the calculation formula 31 of “LR (%) = Δω ÷ Δω _WOT × 100” (corresponding to step S4 in FIG. 5).

  Centrifugal clutch engagement state determination means 40 estimates whether or not centrifugal clutch CL is in an engagement state based on engine speed Ne and load factor LR (corresponding to step S5 in FIG. 5). The centrifugal clutch engagement state determining means 40 determines that the centrifugal clutch CL is not engaged when the engine speed Ne and the engine load factor LR are within a predetermined range (condition 41), that is, in the region C of FIG. The connection state (CL = 1) is determined. On the other hand, when the condition 41 is not satisfied, it is determined that the centrifugal clutch CL is in the connected state (CL = 0).

  Then, the ignition timing table determination means 50 determines which one of the ignition timing table on the advance side or the retard side is to be used based on the Ne-LR map 51 determined in advance by experiments or the like (step of FIG. 5). Corresponding to S6). At this time, if it is determined that the centrifugal clutch CL is in the disconnected state (CL = 1), the Ne-LR map 51 is used by the ignition timing table correction means 52 included in the ignition timing table determination means 50. Regardless of the determination result, correction for selecting the ignition timing table on the advance side is performed (corresponding to step S7 in FIG. 5).

  The ignition timing calculation means 60 stores an advance side ignition timing table 61 (table 1) and a retard side ignition timing table 62 (table 2) determined in advance by experiments or the like. The ignition timing calculation means 60 derives the ignition timing by applying the current engine speed Ne to any one of the ignition timing tables selected by the ignition timing table determination means 50 (corresponding to step S8 in FIG. 5). . Then, the ignition device driving means 15 drives and controls the ignition device 16 using the ignition timing (θig) calculated by the ignition timing calculation means 60.

  FIG. 6 is a Ne-LR map 51 included in the ignition timing table determination unit 50 shown in FIG. In the Ne-LR map 51, the relationship between the engine speed Ne and the engine load factor LR basically applies the retard side table 2 in the high Ne high LR operation region, and the operation of the low Ne constant LR. In the area, it is defined that the advance side table 1 is applied. Note that a fixed value set separately from the ignition timing tables 1 and 2 can be applied to the ignition timing when starting from the engine stop state.

  In order to provide a hysteresis region H between the two operation regions on the advance side and the retard side, the operation region is partitioned by two boundary lines with a high side threshold value LR_Hi and a low side threshold value LR_Lo. That is, in order to switch from the advanced angle side to the retarded angle side, it is necessary to cross the high threshold value LR_Hi, and in order to switch from the retarded angle side to the advanced angle side, it is necessary to cross the low threshold value LR_Lo.

  Even if an unstable state such as an amplitude of the engine load factor LR is created due to the drive of the V-belt type continuously variable transmission TM or the connection of the centrifugal clutch CL, the hysteresis region H is set. This makes it possible to prevent the ignition timing table from being frequently switched.

  Then, in the Ne-LR map 51 according to the present embodiment, when the unconnected state of the centrifugal clutch CL is detected, the advance side table 1 is applied regardless of the determination by the Ne-LR map 51. Therefore, a “centrifugal clutch non-connection region C” in which it is determined that the centrifugal clutch CL is not connected is set.

  In general, the centrifugal clutch CL has a characteristic that the connection rotational speed changes depending on the load factor LR. In the example of this figure, when the throttle is slightly opened from the idle operation indicated by point A and Ne is raised, the centrifugal clutch CL is connected at Ne1, whereas the throttle is suddenly opened from point A. In this case, an operation delay occurs in the clutch shoe interlocked with the centrifugal weight, and the connection rotational speed of the centrifugal clutch CL increases up to Ne2.

  The inventor of the present application states that in such a sudden throttle opening state, even if the detected load factor LR is high, the engine speed Ne suddenly increases because the centrifugal clutch CL is not connected, and knocking is actually performed. Experiments have shown that there is a low possibility of occurrence. Therefore, in this embodiment, when the centrifugal clutch CL is not connected, the advance side table 1 is applied regardless of the determination by the Ne-LR map 51.

  For example, when an operation is performed in which the throttle is suddenly opened from the point A, the point B is passed, and the centrifugal clutch CL is connected, the ignition on the retard side is determined at the point B according to the determination of the Ne-LR map 51. Where the timing table 2 is applied, it is possible to maintain the application of the ignition timing table 1 on the advance side. As a result, even in a low rotation and high load state, it is possible to improve fuel efficiency by using the ignition timing table as the advance side without causing knocking.

  FIG. 7 is a sub-flow showing the procedure of the centrifugal clutch engagement state determination process. This flowchart corresponds to the operation of the centrifugal clutch engagement state determination means 40 shown in FIG. In step S10, it is determined whether or not the engine speed Ne and the engine load factor LR are in the region C.

  This is to detect that the load factor LR is high even though the engine speed is low, and an affirmative determination is made in step S10, that is, it is determined that the centrifugal clutch CL is in an unconnected state. Then, in step S11, the determination parameter CL is set to 1, and a series of control is finished. On the other hand, if it is determined that the centrifugal clutch CL is in the engaged state, the determination parameter CL is set to zero in step S12, and the series of controls is terminated.

  FIG. 8 is a flowchart showing a control procedure for shifting the ignition timing table in accordance with fluctuations in the load factor LR and the engine speed Ne after the application of the ignition timing table on the advance side or the retard side is started. . FIG. 9 is a time chart showing a specific example corresponding to this procedure. The line indicating the transition of the load factor LR has a stepped shape corresponding to the calculation / update of the load factor LR in the same cycle according to the calculation speed of the CPU.

  In step S30, it is determined whether or not the centrifugal clutch CL is in a connected state. If an affirmative determination is made, the process proceeds to step S31, and the ignition timing table (1 or 2) currently in use is determined. If it is determined in step S31 that the angle is on the advance side table 1, it is determined in step S32 whether or not the load factor is equal to or higher than the high side threshold value LR_Hi.

  If an affirmative determination is made in step S32, the process proceeds to step S35 to shift to the ignition timing table 2. This corresponds to the processing D (transition establishment) for switching the ignition timing table to the retard side in response to the load factor LR reaching the threshold value LR_Hi at time t1 in FIG.

  Returning to the determination in step S31, if it is determined that the ignition timing table currently in use is the retard side table 2, the process proceeds to step S36. In step S36, it is determined whether or not the load factor LR is equal to or lower than the low threshold value LR_Low. If a positive determination is made in step S36, the process proceeds to step S37, and the counter CNT is incremented. This corresponds to process E (transition failure) at time t2 in the time chart of FIG. At this time t2, the ignition timing table is not shifted even though the load factor LR becomes equal to or lower than the low threshold value LR_Low. This is because the transition conditions of the ignition timing table are set differently for the advance side and the retard side.

  In step S38 of FIG. 8, it is determined whether or not the counter CNT is equal to or greater than a predetermined value CNT_Low. In the present embodiment, since the predetermined value CNT_Low is set to “2”, a negative determination is made and the process returns to the determination in step S36.

  Note that the flow of affirmative determination in step S32 and proceeding to step S35 is substantially the same as that in which the counter CNT (CNT_Hi) is provided and the predetermined value is set to “1” at the time of transition from the advance side to the retard side. Is synonymous with When the predetermined value CNT_Hi is provided, for example, by setting the predetermined value CNT_Low to “4”, the predetermined value CNT_Hi to “2”, etc., a difference may be provided in the transition conditions of the ignition timing table.

  Returning to the flowchart, if a negative determination is made in step S36, the counter CNT is reset, and the process proceeds to step S35 to shift to the ignition timing table 2. This is because, in order to shift from the retarded angle side to the advanced angle side, the load factor LR needs to be equal to or lower than the low threshold value LR_Low in two consecutive operations. In other words, the engine state is low. This means that the state across the boundary line composed of the threshold value LR_Low needs to be continued for a predetermined time.

  As described above, in order to make a positive determination in step S38 and shift to the ignition timing table 1 on the advance side in step S39, the determination in step S36 needs to be positively determined twice in succession. In FIG. 9, the load factor LR becomes equal to or lower than the low threshold value LR_Low at time t4 following the transition failure at time t3 during the process F, and accordingly, the shift to the ignition timing table 1 on the advance side is made. Corresponds to the established flow.

  In such a setting, in order to improve the fuel efficiency, the advance side table is applied in the widest possible range, and the advance side table is continuously applied even if the retard side table is desired to be applied. Knocking may occur, but there is no risk of knocking even if the retarding side table is applied in a traveling state where the advance side table is desired to be applied, and when traveling on a wavy road, the hysteresis region H It is assumed that hunting is likely to occur in the selection control of the ignition timing table even if is set. That is, the transition condition to the retard angle side table when straddling the boundary line due to the high threshold value LR_Hi from the application range of the advance angle side table, By mitigating the conditions for shifting to the advance side table, the switch from the advance side to the retard side is performed early (short predetermined time), and control with the highest priority on knocking prevention is executed. By making the switching condition from the side to the advance side strict, the occurrence of hunting is prevented.

  As described above, according to the ignition control apparatus for a vehicle engine according to the present invention, the ignition timing is determined based on the engine load factor LR estimated based on the crank angular speed variation Δω and the engine speed Ne. Therefore, it is possible to obtain an appropriate ignition timing with a simple configuration without adding a special device such as an intake negative pressure sensor or a knock sensor for controlling the ignition timing. In particular, a scooter type vehicle using a V-belt type continuously variable transmission and a centrifugal clutch has a characteristic that the detection accuracy of the engine load factor LR is lowered in a low rotation range, so that the low rotation before the centrifugal clutch CL is connected. In the region, it is found that the advance side table is suitable, and a means for determining the connection state of the centrifugal clutch CL based on the engine load factor LR and the engine speed Ne is provided, and forcibly when the centrifugal clutch CL is not connected. In addition, by using the method of applying the advance side table, it is possible to obtain an appropriate ignition timing with a simple configuration even in a scooter type vehicle using a V-belt type continuously variable transmission and a centrifugal clutch.

  In addition, the structure of the power unit, the shape and structure of the engine and continuously variable transmission, the shape and structure of the centrifugal clutch, the shape and structure of the retractor and pickup for detecting the crank pulse, the calculation method of the variation Δω, the Ne-LR map The setting of the advance side table and the retard side table is not limited to the above embodiment, and various changes can be made. For example, the centrifugal clutch connection state determination means may be configured to determine the connection state of the centrifugal clutch based on the difference in rotational speed between the input shaft and the output shaft of the centrifugal clutch. The ignition control device for a vehicle engine according to the present invention can be applied to various vehicles using a centrifugal clutch and a continuously variable transmission, such as a three-wheel ATV vehicle, in addition to a scooter type motorcycle.

DESCRIPTION OF SYMBOLS 1 ... Crankshaft, 10 ... Control part, 11 ... Crank pulse input part, 12 ... Timer, 13 ... Engine speed calculation means, 14 ... Δ (omega) calculation means, 15 ... Ignition device drive means, 16 ... Ignition plug (ignition device) , 20 ... Δω _WOT calculation means, 30 ... engine load factor estimation means, 40 ... centrifugal clutch engagement state determination means, 50 ... ignition timing table determination means, 51 ... Ne-LR map, 52 ... ignition timing table correction means, 60 ... Ignition timing calculation means 61 ... Advance angle side table, 62 ... Delay angle side table, C ... Centrifugal clutch unconnected region, E ... Engine, CL ... Centrifugal clutch, TM ... Continuously variable transmission, V ... V belt, Ne ... Engine speed, LR: Engine load factor, H: Hysteresis region, LR_Hi: High side threshold, LR_Low: Low side threshold, ω1, ω2: Crank angular velocity, Δω ... The amount of variation of the rank angular velocity

Claims (3)

In an ignition control device for a vehicle engine having a belt-type transmission (TM) and a centrifugal clutch (CL) in a drive system,
Engine load factor estimating means (30) for estimating the load factor (LR) of the engine (E) based on the variation (Δω) of the crank angular velocity (ω1, ω2) of the crankshaft (1) of the engine (E). When,
Ignition timing calculating means (60) for calculating the ignition timing of the engine (E) according to the load factor (LR);
A centrifugal clutch connection state determination means (40) for determining a connection state of the centrifugal clutch (CL);
An ignition timing correction means (52) for correcting the ignition timing to the advance side regardless of the ignition timing according to the load factor (LR) when it is determined that the centrifugal clutch (CL) is in an unconnected state; equipped with,
The ignition timing calculation means (60) calculates the ignition timing based on the advance side table (61) or the retard side table (62) selected according to the load factor (LR),
The ignition timing correction means (52) is a case where the retard side table (62) is selected according to the load factor (LR) when it is determined that the centrifugal clutch (CL) is not connected. However, by applying the advance side table (61), the ignition timing is corrected to the advance side,
The ignition timing calculating means (60) is based on the Ne-LR map (51) preliminarily defining the relationship among the load factor (LR), the engine speed (Ne), and the application range of the ignition timing table. The ignition timing is calculated by applying either the angle side table (61) or the retard angle side table (62),
In the Ne-LR map (51), a hysteresis region (H) is set between the application range of the advance side table (61) and the application range of the retard side table (62). An ignition control device for a vehicle engine. The centrifugal clutch connected state determination means (40), according to claim 1, characterized in that to determine the connection state of the centrifugal clutch (CL) on the basis of the load factor (LR) and the engine speed (Ne) Ignition control device for vehicle engine. The hysteresis region (H) is a high side threshold value (LR_Hi) indicating a boundary on the application range side of the advance angle side table (61) and a low side indicating a boundary on the application range side of the retard angle side table (62). It is set as an area surrounded by the threshold (LR_Low),
The ignition timing calculation means (60) indicates that the operating state of the engine (E) represented by the engine speed (Ne) and the load factor (LR) on the Ne-LR map (51) The transition condition from the application range of the retard angle side table (62) to the low threshold value when transitioning from the application range of the table (61) to the retard angle side table (61) when crossing the boundary line by the high threshold value (LR_Hi) The ignition control device for a vehicle engine according to claim 1 or 2 , wherein the ignition control device is configured so as to be more relaxed than a condition for shifting to the advance side table (61) when crossing a boundary line by (LR_Low). .