JP2012215133A - Internal combustion engine control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine control device, capable of avoiding decrease in engine output, even when internal exhaust gas recirculation is performed, while a driver opens a throttle, and thereby capable of improving drivability.SOLUTION: This internal combustion engine control device includes: an exhaust auxiliary cam 158 temporarily opening an exhaust valve in conjunction with a crankshaft during at least a portion of a period in which an intake valve is open; an auxiliary cam control device 210 switching between an auxiliary cam actuation state in which the exhaust valve is temporarily opened and closed during the part of the period and an auxiliary cam non-actuation state in which the in the exhaust valve is not opened or closed during the part of the period, in accordance with an engine rotation speed Ne; and a throttle control device 212 driving a throttle valve 104 in accordance with an accelerator operation amount to open and close an intake passage. The throttle control device 212 increases opening of the throttle valve 104 by a predetermined opening when the throttle valve 104 is open and the auxiliary cam actuation state is established.

Description

  The present invention relates to an internal combustion engine control device, and more particularly to an internal combustion engine control device suitable for use in an internal combustion engine having an exhaust gas recirculation device (EGR valve).

  Recently, in an internal combustion engine, in the latter half of the period when the intake valve is open, the exhaust valve is opened and a part of the exhaust gas is sent into the combustion chamber, that is, the exhaust gas is recirculated (EGR). It is disclosed (see Patent Document 1).

  That is, in the technique described in Patent Document 1, first, when the intake valve is opened, combustion air flows into the combustion chamber of the cylinder via the intake passage, and when the exhaust valve is opened, the gas in the combustion chamber Is discharged to the exhaust system or the exhaust pipe via the exhaust connection pipe. Further, when the intake valve and the exhaust valve are opened, the flow is directly conveyed from the exhaust pipe to the intake pipe via the combustion chamber of the cylinder (internal exhaust gas recirculation). In particular, the above-described internal exhaust gas recirculation is performed by opening the exhaust valve in the second half of the period when the intake valve is open.

Special table 2010-500497 gazette

  However, when the internal exhaust gas is recirculated, the exhaust gas flows from the exhaust pipe into the combustion chamber, so that the combustion air from the supply pipe becomes difficult to enter the combustion chamber, and the amount of energy in the cylinder due to the combustion air decreases. Engine output decreases.

  In particular, when the driver opens the throttle and the engine output decreases, the driver feels that the vehicle has decelerated despite the desire to accelerate, for example, and the driving feeling is inconsistent with the driver's intention. This may give the driver a feeling of poor drivability.

  The present invention has been made in consideration of such a problem, and even when the internal exhaust gas recirculation is performed in a state where the driver has opened the throttle, it is possible to avoid a decrease in the output of the engine, An object of the present invention is to provide a control device for an internal combustion engine capable of improving drivability.

[1] A control device for an internal combustion engine according to claim 1 of the present invention includes a piston (80) that slides in a cylinder (74) as the crankshaft (48) rotates, and a crankshaft (48). An intake cam (128) that drives the intake valve (92) to open and close and an exhaust cam (130) that also opens and closes the exhaust valve (94) to operate the crankshaft (48). In a control device for an internal combustion engine, comprising a throttle valve (104) driven to open and close by a throttle actuator (110) so as to control an intake air amount in an intake passage (86) upstream of the valve (92), the intake valve (92) ) During at least a part of the open period, the exhaust auxiliary cam (158) that temporarily opens the exhaust valve (94) in conjunction with the crankshaft (48), and the engine speed (Ne). According And switching between an auxiliary cam operating state in which the exhaust valve (94) is temporarily opened and closed during the at least part period and an auxiliary cam non-operating state in which the exhaust valve (94) is not opened and closed during the at least part period. An auxiliary cam control device (210), and a throttle control device (212) that drives the throttle valve (104) according to the amount of operation of the accelerator and opens and closes the intake passage (86). No. 212) is characterized in that when the throttle valve (104) is in an open state and the auxiliary cam is activated, the opening degree of the throttle valve (104) is increased by a predetermined opening degree.

[2] The control apparatus for an internal combustion engine according to claim 2 of the present invention is the control apparatus for an internal combustion engine according to claim 1, wherein the throttle control device (212) The throttle valve (104) is set to an opening corresponding to the accelerator operation amount when a predetermined time has elapsed when the accelerator operation amount is constant or when the accelerator operation amount has decreased. .

[3] The control device for an internal combustion engine according to claim 3 of the present invention is the control device for an internal combustion engine according to claim 1, wherein the auxiliary cam control device (210) has a predetermined engine speed (Ne). The auxiliary cam is inactivated when the rotation speed is higher than the rotation speed.

[4] The control apparatus for an internal combustion engine according to claim 4 of the present invention is the control apparatus for an internal combustion engine according to claim 1, wherein the EGR rate to be maintained is Ea, and the opening of the throttle valve (104) is By setting the lift amount of the exhaust auxiliary cam (158) so as to satisfy 0.9Ea <Eb <1.1Ea when the EGR rate when increasing by a predetermined opening is Eb, at least the exhaust The amount of gas reflux is set.

[5] The control device for an internal combustion engine according to claim 5 of the present invention is the control device for an internal combustion engine according to claim 1, wherein the EGR rate to be maintained is Ea, and the opening of the throttle valve (104) is By setting the lift amount of the exhaust auxiliary cam (158) so as to satisfy 0.9Ea <Eb <1.1Ea when the EGR rate when increasing by a predetermined opening is Eb, the throttle The opening degree of the valve (104) and the recirculation amount of the exhaust gas are set.

[6] The control device for an internal combustion engine according to claim 6 of the present invention is the control device for an internal combustion engine according to claim 4 or 5, wherein the EGR rate is exponential with respect to an increase in the recirculation amount of the exhaust gas. Exhaust gas at the opening degree of the throttle valve (104) when the opening degree of the throttle valve (104) is not increased by a predetermined opening degree in the characteristic of the EGR rate to be maintained The slope of the tangent at the recirculation amount is 1 or more, and the characteristic of the EGR rate to be maintained is that the slope of the tangent at the set recirculation amount of the exhaust gas is 1 or more. .

[7] The control device for an internal combustion engine according to claim 7 of the present invention is the control device for an internal combustion engine according to claim 1, wherein the predetermined opening is set according to an acceleration of an operation of the accelerator. It is characterized by that.

(1) According to the first aspect of the present invention, first, the exhaust valve is opened when the intake valve is opened by the exhaust auxiliary cam, whereby a part of the exhaust gas is recirculated to the combustion chamber and the intake passage. Let Thereby, NOx of the exhaust gas is reduced, and the purification efficiency of the exhaust gas is improved. Normally, when a part of the exhaust gas is recirculated, the amount of intake air decreases, and the engine output decreases. However, the throttle valve opening is increased by a predetermined opening, that is, the opening is increased. As a result, it is possible to avoid a decrease in engine output when the intake air supply amount increases and the driver opens the throttle. This leads to improved drivability.

(2) According to the second aspect of the present invention, it is determined that the driver has no longer requested acceleration, and the throttle valve is set to an opening corresponding to the amount of operation of the accelerator (grip or pedal). The exhaust gas amount returned to the combustion chamber (exhaust gas recirculation amount) divided by the sum of the air amount flowing into the combustion chamber and the exhaust gas recirculation amount can be improved, and the exhaust gas purification rate can be increased.

(3) According to the third aspect of the present invention, priority can be given to engine output during high-speed rotation of the engine, and drivability can be improved.

(4) According to the present invention of claim 4, when the opening of the throttle valve is increased by a predetermined opening, that is, when the opening of the throttle valve is increased, the intake efficiency (ηv) of the engine increases and the EGR rate becomes Since the EGR rate Ea to be maintained in advance may be set and the exhaust gas recirculation amount is set to be larger than normal in consideration of the decrease in the EGR rate due to the increase in the throttle opening, the throttle Even if the EGR rate is reduced by increasing the opening, the above-described EGR rate Ea can be substantially maintained. This leads to maintenance of exhaust gas purification performance.

(5) According to the present invention of claim 5, when the opening of the throttle valve is increased by a predetermined opening, that is, when the opening of the throttle valve is increased, the intake efficiency (ηv) of the engine increases and the EGR rate becomes Since the EGR rate Ea to be maintained is set in advance, the recirculation amount of the exhaust gas is set larger than usual in consideration of the decrease in the EGR rate due to the increase in the throttle opening, and the throttle valve Thus, even if the EGR rate decreases due to an increase in the throttle opening, the above-described EGR rate Ea can be substantially maintained. This leads to maintenance of exhaust gas purification performance.

(6) According to the present invention according to claim 6, by using a portion having a steep tangential slope in the characteristics of the EGR rate, the set exhaust gas recirculation amount can be kept small and small. In the region, the effect of the exhaust auxiliary cam and the effect of increasing the opening of the throttle valve can be obtained.

(7) According to the present invention of claim 7, it is possible to avoid a decrease in engine output when the driver opens the throttle, and to increase the intake air supply amount according to the acceleration of the accelerator operation. Therefore, engine output following the driver's accelerator operation can be obtained, and drivability can be improved.

1 is a side view showing a motorcycle with a part of a motorcycle equipped with a control device according to the present embodiment omitted. It is a left view which abbreviate | omits some internal combustion engines and shows them partially. It is a right sectional view of a cylinder head of an internal combustion engine and its vicinity. It is a rear sectional view of the cylinder head of an internal combustion engine and its neighborhood. It is a block diagram which shows the structure of the control apparatus which concerns on this Embodiment. It is explanatory drawing which shows the timing of the auxiliary cam operation state according to an engine speed, and the auxiliary cam non-operation state. It is a flowchart which shows operation | movement of the control apparatus which concerns on this Embodiment. It is a characteristic view which shows the opening / closing timing of an intake valve and an exhaust valve. It is a characteristic view which shows the effect by the opening increase control of a throttle valve. FIG. 10A is a graph showing the difference in the intake air amount at the throttle opening (target value Op) when the exhaust gas recirculation control is performed and when it is not performed, and FIG. 10B is the case where the exhaust gas recirculation control is performed. 6 is a graph showing the difference in the intake air amount at the throttle opening (target value Op + opening increase amount da) when not performed. It is a characteristic view which shows the effect by throttle opening increase control taking the throttle opening 5% and 10% as an example. FIG. 12A is a graph showing a decrease in the EGR rate when the throttle valve opening increase control is performed, and FIG. 12B is a graph showing the EGR rate when the throttle valve opening increase control is performed by increasing the EGR valve lift amount in advance. It is a graph which shows the principle which suppresses the fall of. FIG. 13A is a characteristic diagram showing a change in the EGR rate with respect to the throttle opening, and FIG. 13B is a characteristic diagram showing a change in the EGR rate with respect to the EGR valve lift amount.

  Hereinafter, an embodiment in which a control device for an internal combustion engine according to the present invention is applied to, for example, an internal combustion engine of a motorcycle will be described with reference to FIGS.

  First, a motorcycle 12 in which a motorcycle control device 10 according to the present embodiment is installed will be described with reference to FIG.

  The motorcycle 12 includes a body frame 14, a front wheel 16, a rear wheel 18, an internal combustion engine 20, and the control device 10 according to the present embodiment.

  The body frame 14 has a single main frame 26 extending slightly downward from the head pipe 24 to the rear, and then further bent downward to form a steeply inclined portion 28 to reach the lower end. Further, the down frame 30 extends downward from the head pipe 24 at an obliquely steep angle substantially parallel to the steeply inclined portion 28 of the main frame 26 in a side view.

  A seat rail 34 extends rearward from the upper portion of the steeply inclined portion 28 of the main frame 26 via a gusset 32, and a back stay 36 connecting the center portion of the seat rail 34 and the lower portion of the steeply inclined portion 28 is a seat rail. 34 is supported.

  In the vehicle body frame 14 as described above, the front fork 38 is pivotally supported on the head pipe 24, the front wheel 16 is pivotally supported at the lower end thereof, and the rear wheel 18 is pivotally supported below the steeply inclined portion 28 of the main frame 26. The rear fork 40 extends rearward, the rear wheel 18 is pivotally supported at the rear end thereof, and a rear cushion 42 is interposed between the rear fork 40 and the gusset 32 of the vehicle body frame 14. A fuel tank 44 is installed at the front of the main frame 26 so as to straddle from above, and a seat 46 is supported by the seat rail 34 behind the fuel tank 44.

  The internal combustion engine 20 suspended from the main frame 26 and the down frame 30 is an SOHC type air-cooled single-cylinder four-cycle internal combustion engine, and a crankshaft 48 (see FIG. 2) is directed to the vehicle body in the vehicle body width direction. The cylinder block 50, the cylinder head 52, and the head cover 54 are suspended in an upright posture by tilting the cylinder slightly forward. The fuel tank 44 covers the upper portion of the head cover 54 at the upper part of the slightly tilted cylinder of the internal combustion engine 20.

  An intake pipe 56 extends rearward from the cylinder head 52 of the internal combustion engine 20 and reaches an air cleaner 58 via a throttle body, and an exhaust pipe 60 extends forward from the cylinder head 52 and bends downward to bend the internal combustion engine 20. The rear part 18 extends rearward and reaches the muffler 62 on the right side of the rear wheel 18.

  Next, the internal combustion engine 20 will be described with reference to FIGS.

  A crankcase 64 that supports the crankshaft 48 is formed with a transmission chamber 68 that houses a transmission behind a crank chamber 66 in which the crankshaft 48 is disposed. From the transmission chamber 68, an output shaft 70 of the transmission is on the left. It protrudes outward and constitutes a power unit. Below the crank chamber 66, an oil sump 72 is formed integrally with the bottom wall to bulge somewhat downward to store oil. The crankcase 66 forming the crank chamber 66, the transmission chamber 68, and the oil reservoir 72 has a left-right split structure.

  On the front crank chamber 66 of the crankcase 64, as shown in FIG. 3, a cylinder block 50 having one cylinder 74 and a cylinder head 52 are stacked on the cylinder block 50 via a gasket. The cylinder head 52 and the cylinder block 50 are integrally fastened to the crankcase 64 (see FIG. 2) together with the camshaft holder 78 by the head bolt 76, and the head cover 54 covers the cylinder head 52 via an elastic seal member 79. . The cylinder block 50, the cylinder head 52, and the head cover 54 that are overlaid on the crankcase 64 (see FIG. 2) extend upward from the crankcase 64 in a slightly tilted posture (see FIG. 2).

  A piston 80 is slidably mounted in a cylinder 74 of the cylinder block 50, and the piston 80 and the crankshaft 48 (see FIG. 2) are connected by a connecting rod 82 to constitute a crank mechanism.

  A combustion chamber 84 is formed in the cylinder head 52 so as to face the piston 80 in the cylinder axial direction corresponding to the cylinder 74, and an intake passage 86 extends rearward from the combustion chamber 84 and forwards from the combustion chamber 84. An exhaust passage 88 extends, and a spark plug 90 (see FIG. 4) is attached to the ceiling wall of the combustion chamber 84 with the tip facing the combustion chamber 84.

  As shown in FIG. 3, the intake valve 92 and the exhaust valve 94 that are slidably supported by a valve guide integrally fitted to the cylinder head 52 are driven by a valve mechanism 96 provided in the internal combustion engine 20. Thus, the intake opening of the intake passage 86 and the exhaust opening of the exhaust passage 88 are opened and closed in synchronization with the rotation of the crankshaft 48 (see FIG. 2).

  A throttle body 100 is connected to the external extension 98 of the intake passage 86. The external extension 98 and the throttle body 100 are connected to each other by a band 102. A throttle valve 104 (butterfly valve) is pivotally supported on the throttle body 100. A gear 106 is attached to a shaft 104 a that supports the throttle valve 104, and the gear 106 is connected to a pinion 114 of a throttle motor 112 as a throttle actuator 110 via an intermediate gear 108. When the throttle motor 112 is driven, the throttle valve 104 is rotated according to the rotation amount. The amount of intake air taken into the intake passage 86 is controlled by the rotation angle of the throttle valve 104, that is, the throttle opening.

  A fuel injection valve 116 for injecting fuel into the intake passage 86 is attached to the throttle body 100 on the downstream side of the throttle valve 104. The fuel injection amount by the fuel injection valve 116 is calculated by a control unit (ECU) based on various parameters such as throttle opening, engine speed, and atmospheric temperature. The fuel injection valve 116 has a solenoid valve, and supplies the amount of fuel calculated by the ECU to the intake passage 86 by controlling the energization time of the solenoid valve.

  Next, the valve mechanism 96 will be described with reference to FIGS.

  The valve operating mechanism 96 is an SOHC type valve operating mechanism in which a single valve operating cam shaft 118 is pivotally supported in a left-right direction on a camshaft holder 78 fixed on the cylinder head 52. Rocker arm shafts 120 and 122 are supported by the camshaft holder 78 on the diagonally front and rear of the camshaft 118, and an intake rocker arm 124 is pivotally supported by the rear rocker arm shaft 122 in a swingable manner. 120, an exhaust rocker arm 126 is pivotally supported at the center so as to be swingable.

  A cylindrical steady cam member 132 having an intake cam lobe 128 and an exhaust cam lobe 130 arranged side by side on the outer peripheral surface is press-fitted into the valve camshaft 118, and the steady cam member 132 is integrally removed from the valve camshaft 118. It is fitted.

  The intake rocker arm 124 has one end roller 134 in contact with the intake cam lobe 128 of the stationary cam member 132, the other end in contact with the upper end of the valve stem of the intake valve 92, and the other exhaust rocker arm 126 has one end roller 136 stationary. The cam member 132 is in contact with the exhaust cam lobe 130, and the other end is in contact with the upper end of the valve stem of the exhaust valve 94. The rocker arm 124 and the exhaust rocker arm 126 swing at a predetermined timing to open and close the intake valve 92 and the exhaust valve 94.

  The valve camshaft 118 has a driven cam chain sprocket 138 fixed to the left shaft end (see FIG. 4).

  On the other hand, as shown in FIG. 2, a drive cam chain sprocket 140 is fitted on the crankshaft 48, and a cam chain 142 is installed between the drive cam chain sprocket 140 and a driven cam chain sprocket 138 thereabove. Then, the rotational power of the crankshaft 48 is transmitted to the rotation of the valve operating camshaft 118 through the cam chain 142 at half the rotational speed of the crankshaft 48, and the intake rocker arm 124 is synchronized with the crankshaft 48. The exhaust rocker arm 126 is swung to open and close the intake valve 92 and the exhaust valve 94 at the required timing.

  As shown in FIG. 4, on the left side of the cylinder block 50, cylinder head 52, and head cover 54, in the cam chain chambers 144, 146 and 148, as shown in FIG. The front side of the cam chain 142 spanned between the driven cam chain sprocket 138 and the chain guide 150, which is slightly curved and extends up and down, guides it, while the rear rear side of the cam chain 142 has an arcuate shape. A curved tension slipper 152 is pressed against the cam chain 142 to maintain an appropriate tension. The tension slipper 152 is pressed behind by a tension lifter 154.

  The valve camshaft 118 is a cylindrical member having a central shaft hole, and has a maximum outer diameter spline forming portion at the center in the axial direction, and a cam fixing portion reduced in diameter via a stepped portion to the right of the spline forming portion. And a journal portion further reduced in diameter at the right end.

  A steady cam member 132 is press-fitted and fixed at a predetermined relative angle to the cam fixing portion of the valve cam shaft 118. The steady cam member 132 is press-fitted into the cam fixing portion of the valve camshaft 118 with the exhaust cam lobe 130 on the left side and the intake cam lobe 128 on the right side until it comes into contact with the spline forming portion from the right side. It is integrated adjacent to the forming part.

  As described above, the steady cam member 132 is integrally mounted on the valve operating cam shaft 118 on the cam fixing portion, and the variable cam member 156 is spline-fitted on the spline forming portion. The variable cam member 156 has a variable cam lobe 158 (exhaust auxiliary cam) formed on the right side on the outer peripheral surface. The variable cam lobe 158 has a base circle whose outer periphery is mostly the same diameter as or slightly smaller than the base circle of the exhaust cam lobe 130, and a cam crest with a small lift amount protrudes at a predetermined phase angle. When the lift amount of the variable cam lobe 158 is increased, the exhaust gas recirculation amount increases.

  A bearing 160 is fitted to the right journal portion protruding to the right side of the cam fixing portion into which the steady cam member 132 is press-fitted in the valve camshaft 118, and the left side of the spline forming portion in which the variable cam member 156 is spline fitted. A bearing 162 is fitted and inserted into the left cylindrical portion, and a flange portion 164 is press-fitted at a predetermined relative angle via a key to sandwich the bearing 162 with the spline forming portion.

  The driven cam chain sprocket 138 (see FIG. 2) has a central circular hole fitted to the left end exposed to the left of the flange portion 164 of the valve drive cam shaft 118, and is fixed to the flange portion 164 with a screw or the like (see FIG. 4). ).

  A slide rod 166 of a slider mechanism 165 that slides and displaces the variable cam member 156 is fitted into the central shaft hole of the valve cam shaft 118 so as to be slidable in the left-right axis direction. The slide rod 166 is inserted into the central shaft hole of the valve cam shaft 118, and one connecting pin 168 is inserted. The connecting pin 168 moves integrally with the variable cam member 156.

  Accordingly, when the slide rod 166 is slid in the left and right axial directions within the central shaft hole, the connecting pin 168 is guided and moved together by the long hole of the valve cam shaft 118, and the variable cam member 156 is integrated with the connecting pin 168. Moves in the axial direction and is displaced.

  The inner peripheral surface of the right end of the central shaft hole of the valve camshaft 118 is provided with a female screw. When the coil spring 170 is inserted into the central shaft hole from the right and the flanged bolt 172 is screwed together, the coil spring 170 becomes a slide rod. The slide rod 166 is urged to the left by being sandwiched between the bolt 172 and the flanged bolt 172, and the left end of the slide rod 166 is protruded to the left from the valve operating cam shaft 118. Thus, a slider shaft for displacing the variable cam member 156 in the axial direction is configured.

  Thus, the slider mechanism 165 is formed in the central shaft hole of the valve camshaft 118, and the stationary cam member 132, the variable cam member 156, the driven cam chain sprocket 138, and the bearings 160 and 162 are arranged on the outer periphery of the valve camshaft 118. In the assembled state, the camshaft holder 78 is inserted from the left side into the shaft holes of the left bearing wall 174 and the right bearing wall 176 that project opposite to the left and right, and the right bearing 160 is inserted into the shaft hole of the right bearing wall 176. The left bearing 162 is fitted into the shaft hole of the left bearing wall 174, and the valve camshaft 118 is rotatably supported by the camshaft holder 78 via the bearings 160 and 162. It rotates with the variable cam member 156 integrally with 132 (refer FIG. 4). The right bearing 160 is positioned in contact with the stepped portion of the right bearing wall 176, and the left bearing 162 is positioned on the left side by a stop plate 180 fixed to the left bearing wall 174 by a bolt 178 and falls off. Is prevented.

  Referring to FIG. 4, when the slide rod 166 urged leftward by the coil spring 170 is pushed rightward against the urging force of the coil spring 170, as shown by the solid line in FIG. The variable cam member 156 is slid to the right via 168 and close to the exhaust cam lobe 130 on the left side of the steady cam member 132, and the roller 136 of the exhaust rocker arm 126 straddles both the exhaust cam lobe 130 and the variable cam lobe 158. Thus, in addition to the normal opening / closing timing of the exhaust valve 94 (see FIG. 3) by the exhaust cam lobe 130, the exhaust valve 94 is opened / closed by the variable cam lobe 158. The opening and closing of the exhaust valve 94 by the variable cam lobe 158 executes EGR (exhaust gas recirculation).

  On the other hand, when the slide rod 166 is moved to the left by the coil spring 170, the variable cam member 156 is slid to the left via the connecting pin 168 as shown by a two-dot chain line in FIG. When the distance is greater than a predetermined distance, the roller 136 of the exhaust rocker arm 126 is not in contact with the variable cam lobe 158, but is in contact with only the exhaust cam lobe 130, and the exhaust valve 94 is opened and closed at the timing of the normal exhaust valve. .

  A variable valve timing drive mechanism 182 that projects to the left from the valve camshaft 118 and presses the left end of the slide rod 166 biased to the left by the coil spring 170 to the right to drive the slider mechanism 165 is a driven cam chain sprocket. It is provided on the left side of 138 (see FIG. 4).

  The variable valve timing drive mechanism 182 includes an electromagnetic solenoid 184 as an auxiliary cam actuator 183 and a swing arm 186 that transmits the drive of the electromagnetic solenoid 184 to the slider mechanism 165, and the electromagnetic solenoid 184 is located above the ceiling wall 188 of the head cover 54. The swing arm 186 is pivotally supported by the cam chain chamber 148 of the head cover 54 so as to be swingable.

  The head cover 54 has a substantially rectangular bowl shape with the ceiling wall 188 and the rectangular cylindrical peripheral wall 190. The central portion of the ceiling wall 188 that covers the cam chain chamber 148 in the front-rear direction protrudes thickly upward to form a central protrusion 192. A central gap 194 having a predetermined width is drilled from the cam chain chamber 148 side in the central portion of the central protrusion 192 in the front-rear direction, and a circular hole 196 drilled to the left from the right side surface of the central protrusion 192 is formed in the center. The gap 194 is reached.

  A plunger 200 protrudes from an attachment cylindrical portion 198 protruding from one end surface of the cylindrical main body of the electromagnetic solenoid 184 so as to advance and retract. A mounting flange 202 extends forward and backward from the main body of the electromagnetic solenoid 184. The electromagnetic solenoid 184 is attached to the central protrusion 192 from the right side with the plunger 200 on the left side.

  As shown in FIG. 5, the control device 10 according to the present embodiment includes the exhaust auxiliary cam 158 (variable cam lobe), the auxiliary cam control device 210, and the throttle control device 212 described above.

  The auxiliary cam control device 210 drives the auxiliary cam actuator 183 in accordance with the engine speed Ne from the engine speed sensor 214 to switch between the auxiliary cam operating state and the auxiliary cam non-operating state. Information about the current state is output to the throttle control device 212 as a state signal. The auxiliary cam operating state is a state in which the exhaust valve 94 is temporarily opened and closed by moving the exhaust auxiliary cam 158 in conjunction with the crankshaft 48 during a part of the period during which the intake valve 92 is open. The auxiliary cam non-operation state indicates a state in which the exhaust valve 94 is not opened / closed during the partial period described above.

  As shown in FIG. 6, the auxiliary cam control device 210 is in an auxiliary cam operating state when the engine speed is in the range of 3000 to 6000 rpm (threshold range), for example, and the engine speed is less than 3000 rpm or exceeds 6000 rpm. In such a case, the auxiliary cam is controlled so as not to operate.

  The throttle control device 212 controls the throttle actuator 110 to drive the throttle valve 104 and open / close the intake passage 86 according to the operation amount of the throttle grip. The operation amount of the throttle grip is obtained from a detection value from a throttle sensor 216 that detects a rotation angle of a throttle pipe provided on the inner peripheral side of the throttle grip.

  In particular, the throttle control device 212 is used when the detected value from the throttle sensor 216 indicates an operation of opening the throttle valve 104 and when the auxiliary cam control device 210 sets the auxiliary cam operation state. The opening of 104 is increased by a predetermined opening, that is, the opening is increased. The opening increment da is obtained from map information 218 set in advance, for example. In the map information 218, for example, information on the opening increase amount da corresponding to the acceleration of the throttle grip is arranged. The throttle control device 212 calculates the acceleration based on the change in the detection value from the throttle sensor 216, and reads the opening increase amount da corresponding to the calculated acceleration from the map information 218.

  Based on the detection value from the throttle opening sensor 220 that detects the amount of rotation of the throttle valve 104, the throttle control device 212 determines that the opening of the throttle valve 104 is an opening (target value Op) corresponding to the operation amount of the throttle grip. Alternatively, the throttle actuator 110 is feedback-controlled so that the target value Op + a predetermined opening degree (opening amount da) is obtained.

  Here, the operation of the control device 10 according to the present embodiment will be described with reference to the flowchart of FIG. 7 and the operation explanatory diagrams of FIGS. 8 to 13B.

  First, in step S1 of FIG. 7, the engine is started. At this stage, since the engine speed Ne is smaller than the lower limit of the threshold range, the auxiliary cam control device 210 sets the auxiliary cam inoperative state. As a result, as shown in FIG. 8, the exhaust valve 94 operates according to the opening / closing timing indicated by the curve L1, and the intake valve 92 operates according to the opening / closing timing indicated by the curve L2.

  In step S2 of FIG. 7, the throttle control device 212 determines whether or not the throttle grip is being opened. This determination is made based on the detection value from the throttle sensor 216.

  If the throttle grip is opened, in the next step S3, the auxiliary cam control device 210 determines whether or not the engine speed Ne is within the threshold range. This determination is made based on the detection value from the engine speed sensor 214.

  If the engine speed Ne is within the threshold range, in the next step S4, the throttle control device 212 sets the throttle valve 104 to the opening (target value Op) corresponding to the throttle grip operation amount. The throttle actuator 110 is feedback-controlled so that the opening is obtained by adding the opening increase amount da corresponding to the acceleration of the grip.

  Thereafter, in step S5, the auxiliary cam control device 210 drives the auxiliary cam actuator 183 to set the auxiliary cam operating state. As a result, as shown by a curve L3 in FIG. 8, the exhaust valve 94 opens and closes when the exhaust auxiliary cam 158 moves in conjunction with the crankshaft 48 in the latter half of the period during which the intake valve 92 is open. . That is, an exhaust gas recirculation operation is performed.

  Normally, as the throttle valve 104 is gradually opened, the engine output gradually increases according to the opening of the throttle valve 104 as shown by the solid line La in FIG. 9, but the engine speed Ne is 3000 rpm. When the exhaust gas recirculation operation is started at this stage, the output of the engine drops as shown by the solid line Lb. As shown in FIG. 10A, when the exhaust gas recirculation operation is performed (the auxiliary cam is activated), the intake air amount (see point B) when the throttle opening is the target value Op is the inflow of exhaust gas. As a result, the amount of intake air is lower than the amount of intake air when the exhaust gas recirculation operation is not performed (the auxiliary cam is not operating) (see point A), and the amount of energy in the cylinder due to the intake air is reduced.

  However, in the present embodiment, in step S4, the throttle opening is the opening obtained by adding the opening increase amount da corresponding to the acceleration of the throttle grip to the target value Op. Further, since the intake air amount in the auxiliary cam non-operating state is substantially the same as the intake air amount at the target value Op in the auxiliary cam operating state, a drop in engine output occurs as shown by the solid line Lc in FIG. Disappear.

  In step S6 of FIG. 7, the throttle control device 212 is operated so that the throttle grip is in a steady state (a constant open state over a predetermined time) or the throttle grip is in the closing direction of the throttle valve 104. Then, it is determined whether or not the operation amount of the throttle grip is reduced. This determination is made based on the detection value from the throttle sensor 216.

  If the throttle grip is operated in a direction to further open the throttle valve 104, the process returns to step S4, and the processes after step S4 are repeated.

  If it is determined in step S6 that the throttle grip is in a steady state or the throttle grip operation amount is reduced, in the next step S7, the throttle control device 212 determines that the throttle valve 104 opening degree is the throttle grip operation amount. The throttle actuator 110 is feedback-controlled so that the opening degree (target value Op) is in accordance with. That is, the opening increase of the throttle valve 104 is released.

  The processing in steps S4 to S7 described above will be described with reference to FIG. 11. For example, when attention is paid to the characteristics of the engine output with a throttle opening of 5%, normally, as indicated by the curve Ld, the engine speed Ne is indicated. When exhaust gas reaches the lower limit value (for example, 3000 rpm), the exhaust gas recirculation starts, so the engine output decreases and the engine speed Ne is the upper limit value (for example, 6000 rpm). Since the exhaust gas recirculation ends at this point, the engine output returns to the output before the start of the exhaust gas recirculation. This is the same when the throttle opening is 10%, and as shown by the curve Le, the engine output is generally higher than when the throttle opening is 5%, but the engine is increased with the start of exhaust gas recirculation. The output decreases, and the engine output is restored with the end of exhaust gas recirculation.

  However, in this embodiment, since the opening of the throttle valve 104 is increased in step S4, for example, when the target value Op is 5% of the throttle opening, the opening of the throttle is increased to 10 by increasing the opening. %, When the throttle opening is 5%, the curve shifts from the curve Lb when the throttle opening is 5% to the curve Le when the throttle opening is 10%. Increased up to the case. Thereafter, as the exhaust gas recirculation ends, as shown by a curve Lg, the curve Le returns when the throttle opening is 10% to the curve Ld when the throttle opening is 5%.

  On the other hand, if it is determined in step S3 of FIG. 7 that the engine speed Ne is outside the threshold range, in step S8, the auxiliary cam control device 210 determines that the current state is the auxiliary cam non-operating state. If there is, the auxiliary cam non-operation state is maintained as it is, and if the current state is the auxiliary cam operation state, the auxiliary cam actuator 183 is driven to shift to the auxiliary cam non-operation state.

  In step S2 described above, when it is determined that the throttle grip is an operation for closing the throttle valve 104, or when the process in step S7 is completed or the process in step S8 is completed, In step S9, it is determined whether the request is an end request (power-off, engine stop request, etc.). If it is not an end request, the process returns to step S2 to repeat the processes after step S2.

  Then, when it is determined in step S9 that the request is to be terminated, the processing operation in the control device 10 according to the present embodiment is terminated.

  Thus, in the control apparatus 10 according to the present embodiment, first, the exhaust valve 94 is opened by the exhaust auxiliary cam 158 when the intake valve 92 is open, whereby a part of the exhaust gas is combusted in the combustion chamber 84. And recirculate to the intake passage 86. Thereby, NOx of the exhaust gas is reduced, and the purification efficiency of the exhaust gas is improved. Normally, when a part of the exhaust gas is recirculated, the amount of intake air decreases, and the engine output decreases. However, the opening of the throttle valve 104 is increased by a predetermined opening, that is, the opening is increased. As a result, the intake air supply amount increases, and a decrease in engine output when the driver opens the throttle can be avoided. This leads to improved drivability.

  In particular, since the amount of opening increase is set according to the acceleration of the throttle grip operation, engine output following the driver's throttle grip operation can be obtained, and drivability is further improved. Can do.

  If it is determined in step S6 that the throttle grip is in a steady state or the amount of operation of the throttle grip is reduced, it is determined that the driver has no longer requested acceleration, and the increase in opening of the throttle valve 104 is canceled, The throttle valve 104 has an opening (target value Op) corresponding to the throttle grip operation amount. As a result, the EGR rate (the value obtained by dividing the amount of exhaust gas returned to the combustion chamber 84 (exhaust gas recirculation amount) by the sum of the amount of air flowing into the combustion chamber 84 and the exhaust gas recirculation amount) can be improved. The purification rate can be increased.

  Further, in step S3, when the engine speed Ne exceeds the upper limit of the threshold range, the auxiliary cam is inactivated, so that the engine output can be prioritized during high speed engine rotation, and drivability Can be improved.

  By the way, as shown in FIG. 12A, the exhaust gas recirculation amount (EGR valve lift amount) by the exhaust auxiliary cam 158 is constant (see point X). Thus, since the amount of intake air increases, the EGR rate decreases. That is, as shown in FIG. 13A, the EGR rate decreases as the throttle opening increases. The EGR rate is preferably maintained at a preset EGR rate from the viewpoint of exhaust gas purification and the like.

Therefore, in the present embodiment, as shown by the two-dot chain line in FIG. 3, the size of the exhaust auxiliary cam 158 (variable cam lobe) is made larger than that of the normal exhaust auxiliary cam, and the solid line L4 in FIG. As shown in FIG. 13B, the EGR valve lift amount is increased more than usual. Thereby, as shown to the point Z of FIG. 12B, the fall of an EGR rate can be suppressed and it can maintain at the EGR rate substantially the same as a normal EGR rate. In this case, when the EGR rate to be maintained (normal EGR rate) is Ea, and the EGR rate when the opening of the throttle valve 104 is increased by a predetermined opening is Eb,
0.9Ea <Eb <1.1Ea
It is preferable that at least the exhaust gas recirculation amount is set so as to satisfy the above. Particularly preferably, the opening degree of the throttle valve 104 (target value Op) and the exhaust gas recirculation amount are set so as to satisfy the above-described magnitude relationship. Thereby, maintenance of exhaust gas purification performance can be aimed at.

  The size of the exhaust auxiliary cam 158 is set based on at least the set exhaust gas recirculation amount (or the throttle valve 104 opening (target value Op) and exhaust gas recirculation amount). It is preferable to set the size so that the exhaust valve does not open. To achieve this, it is preferable to note the following.

  That is, as shown in FIG. 12B and the like, the EGR rate has a characteristic of exponentially increasing with respect to an increase in the exhaust gas recirculation amount. Accordingly, in the characteristics of the EGR rate to be maintained, the exhaust gas recirculation amount at the opening of the throttle valve 104 (target value Op) when the opening of the throttle valve 104 is not increased by a predetermined opening (see point X). In the characteristic of the EGR rate to be maintained, the slope of the tangent at the set exhaust gas recirculation amount (see point Z) is 1 or more. As a result, by using a portion with a steep tangential slope in the characteristics of the EGR rate, it is possible to suppress the set exhaust gas recirculation amount to a small value, that is, to minimize the increase in the size of the exhaust auxiliary cam. The effect of the exhaust auxiliary cam 158 and the effect of increasing the opening of the throttle valve 104 can be obtained in a small area.

  Further, in the present embodiment, exhaust gas recirculation is performed by the exhaust auxiliary cam (variable cam lobe 158), so that the air downstream of the exhaust valve 94 is directly introduced into the combustion chamber 84 from the exhaust passage 88. The gas can be introduced into the combustion chamber 84 at a desired timing without delay. Therefore, the exhaust gas purification efficiency can be improved by performing an operation such as recirculating a large amount of the exhaust gas. For example, in a four-wheeled vehicle, the exhaust gas is taken out from the exhaust pipe, and the exhaust gas is recirculated to the intake passage via the EGR valve. Therefore, the time lag is longer than the mechanism using the exhaust auxiliary cam of the present embodiment. appear. On the other hand, in the present embodiment, as described above, high-temperature exhaust gas can be introduced into the combustion chamber without delay at a desired timing, and the configuration itself is small, so that the arrangement space is limited. It is suitable for use in a vehicle such as a motorcycle 12.

  Note that the control device for an internal combustion engine according to the present invention is not limited to the above-described embodiment, and it is needless to say that various configurations can be adopted without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 ... Control apparatus 12 ... Motorcycle 20 ... Internal combustion engine 48 ... Crankshaft 74 ... Cylinder 80 ... Piston 92 ... Intake valve 94 ... Exhaust valve 104 ... Throttle valve 110 ... Throttle actuator 128 ... Intake cam lobe 130 ... Exhaust cam lobe 158 ... Exhaust assist Cam 183 ... Auxiliary cam actuator 210 ... Auxiliary cam control device 212 ... Throttle control device 214 ... Engine speed sensor 216 ... Throttle sensor 220 ... Throttle opening sensor

Claims (7)

A piston (80) that slides in the cylinder (74) as the crankshaft (48) rotates, an intake cam (128) that opens and closes the intake valve (92) in conjunction with the crankshaft (48), Similarly, the intake air amount is controlled by the exhaust cam (130) that opens and closes the exhaust valve (94) in conjunction with the crankshaft (48) and the intake passage (86) on the upstream side of the intake valve (92) in the entire operation region. An internal combustion engine control device comprising a throttle valve (104) that is driven to open and close by a throttle actuator (110).
An exhaust auxiliary cam (158) that temporarily opens the exhaust valve (94) in conjunction with the crankshaft (48) during at least a part of the period during which the intake valve (92) is open;
Depending on the engine speed (Ne), an auxiliary cam operating state for temporarily opening and closing the exhaust valve (94) in the at least part of the period, and opening and closing of the exhaust valve (94) in the at least part of the period An auxiliary cam control device (210) for switching the auxiliary cam non-operating state,
A throttle control device (212) that drives the throttle valve (104) according to the amount of operation of the accelerator and opens and closes the intake passage (86);
The throttle control device (212) increases the opening of the throttle valve (104) by a predetermined opening when the throttle valve (104) is open and the auxiliary cam is activated. A control device for an internal combustion engine. The control apparatus for an internal combustion engine according to claim 1,
In the auxiliary cam operating state, the throttle control device (212) is configured to detect the throttle valve (104) when the accelerator operation amount is constant for a predetermined time or when the accelerator operation amount is reduced. ) Is an opening corresponding to the amount of operation of the accelerator. The control apparatus for an internal combustion engine according to claim 1,
The control device for an internal combustion engine, wherein the auxiliary cam control device (210) sets the auxiliary cam inoperative when the engine speed (Ne) is equal to or higher than a predetermined speed. The control apparatus for an internal combustion engine according to claim 1,
When the EGR rate to be maintained is Ea, and the EGR rate when the opening of the throttle valve (104) is increased by a predetermined opening is Eb,
0.9Ea <Eb <1.1Ea
A control device for an internal combustion engine, wherein at least the exhaust gas recirculation amount is set by setting the lift amount of the exhaust auxiliary cam (158) so as to satisfy the above. The control apparatus for an internal combustion engine according to claim 1,
When the EGR rate to be maintained is Ea, and the EGR rate when the opening of the throttle valve (104) is increased by a predetermined opening is Eb,
0.9Ea <Eb <1.1Ea
The internal combustion engine is characterized in that the opening degree of the throttle valve (104) and the recirculation amount of the exhaust gas are set by setting the lift amount of the exhaust auxiliary cam (158) so as to satisfy Control device. The control apparatus for an internal combustion engine according to claim 4 or 5,
The EGR rate has a characteristic of increasing exponentially with an increase in the exhaust gas recirculation amount,
In the characteristic of the EGR rate to be maintained, the slope of the tangent line at the exhaust gas recirculation amount at the opening degree of the throttle valve (104) when the opening degree of the throttle valve (104) is not increased by a predetermined opening degree. Is 1 or more, and
The control apparatus for an internal combustion engine, characterized in that, in the characteristic of the EGR rate to be maintained, a slope of a tangent at a set recirculation amount of the exhaust gas is 1 or more. The control apparatus for an internal combustion engine according to claim 1,
The control apparatus for an internal combustion engine, wherein the predetermined opening is set according to an acceleration of an operation of the accelerator.

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