Title of Invention

"A CONTROL APPARATUS FOR STARTING AN ENGINE"

Abstract

A control apparatus (80) for starting an engine (E) having an intake valve (38) mounted in a position upward of an exhaust valve (39) and including also a kick pedal and a starter motor (45), the control apparatus comprising, a decompression device opening the exhaust valve while the engine (E) remains stationary, an ignition device (87) firing the engine E at a predetermined timing characterized by a misfire device (87a) causing the engine to misfire by immobilizing the ignition device, wherein the misfire device (87a) is designed to let the engine (E) misfire only for a predetermined period of time while the engine is started using the starter motor (45).

Full Text

The present invention relates to a control apparatus for starting an engine. [Technical Field] [0001] The present invention relates generally to an engine starting control apparatus. More specifically, the present invention relates to a control, apparatus for starting an engine, in which an intake valve is disposed upward of an exhaust valve and which, is mounted with an auto decompression device for improving engine start ability during a next attempt to start the engine by opening the exhaust valve while the engine remains stationary. [Background Art] [0002] In many cases in which a crankshaft rotates by inertia immediately before the engine stops, a piston having received a compression load-charging a compression stroke is unable to overcome a top dead, center, thus causing the crankshaft to rotate slightly backward before the engine is brought to a complete stop. Patent Document 1 discloses an art relating to an auto decompression device making use of such a phenomenon, in. which the engine rotates backward immediately before stopping. The decompression device makes use of this phenomenon to slightly open an exhaust valve. The device thereby lessens a cranking load during starting of the engine next time, thus improving startability. [Patent Document 1] Japanese Patent Laid-open No. Sho 63-162911 [Disclosure of the Invention] [Problem to be Solved by the Invention] [0003] Conventionally, an engine mounted with an auto decompression device can at times stop during a valve overlap, which is a period during which both the intake valve and the exhaust valve open. There is available a type of engine called a horizontal engine, in which pistons are supported in a position permitting a horizontal movement and the intake valve is disposed upward of the exhaust valve. If an auto decompression device such as that described above is applied to this type of engine, fuel gas left in a carburetor or an intake pipe falls downward by gravity as time elapses after running, accumulating inside an exhaust pipe. If the engine is started in this condition, the residual gas left inside the exhaust pipe is drawn into a cylinder as the piston makes a downward movement after the top dead center. Afterburning could result if the residual gas is ignited by a starting fire. [0004] An object of the present invention is to solve the aforementioned problem of the related art and, in a horizontal engine mounted with an auto decompression device, to prevent afterburning from occurring during starting of the engine. [Means for Solving the Problem] [0005] To achieve the foregoing object, according to the present invention, there is provided a control apparatus for starting an engine, in which an intake valve is used in a position upward of an exhaust valve and which is provided also with a kick pedal and a starter motor. The control apparatus includes a decompression device, an ignition device, and a misfire device. The decompression device opens the exhaust valve while the engine remains stationary. The ignition device fires the engine at a predetermined timing. The misfire device causes the engine to misfire by immobilizing the ignition device. The misfire device is designed to let the engine misfire only for a predetermined period of time while the engine started during the next starting sequence. (3) Further, according to the second aspect of the present invention, the arrangement of connecting the starter motor to the engine via the reduction gearing makes it possible to build a compact starter motor. (4) According to a third aspect of the present invention, when a four-cycle engine is started, ignition by the first starting fire and a main fire following the starting fire can be prohibited regardless of a crank angle of the engine. Afterburning with auto decompression set in the active state can be positively prevented. [Best Mode for Carrying out the Invention] [0007] A preferred embodiment of the present invention will be described with reference to the accompanying [Brief Description of the Drawings] [0029] [FIG. 1] FIG. 1 is a general side elevational view showing a motorcycle, to which the engine starting control apparatus according to the present invention is applied. [FIG. 2] FIG. 2 is a cross sectional taken on surface A-A of FIG. 1. [FIG. 3] FIG. 3 is an enlarged cross sectional view taken along line B-B of FIG. 2. [FIG. 4] FIG. 4 is a cross sectional view taken along line C-C of FIG. 2. [FIG. 5] FIG. 5 is a block diagram showing configuration of a principal part of the engine starting control apparatus according to the present invention. [FIG. 6] FIG. 6 is a functional block diagram of an ignition device. [FIG. 7] FIG. 7 is a flowchart showing steps of starting misfire control. [FIG. 8] FIG. 8 is a timing chart for the starting misfire control. FIG. 1 is a general side elevational view showing a scooter type motorcycle, to which the engine starting control apparatus according to the present invention is applied. [0008] A vehicle body frame 1 constituting a vehicular framework generally includes a down tube 6 and a main pipe 7. The main pipe 7 supports a fuel tank and a storage box (both not shown). A seat 8 is disposed above the main pipe 7. [0009] There is provided at a front portion of the vehicle body a handlebar 11 journaled on, and disposed upward of, a steering head 5. A front fork 12 extends downwardly from the steering head 5. A front wheel FW is journaled on the front fork 12 at a lower end thereof. An upper portion of the handlebar 11 is covered with a handlebar cover 13 serving also as an instrument panel. A bracket 15 is provided in a protruding condition at a lower end of a riser of the main pipe 7. A hanger bracket 18 of a swing unit 2 is swingably connected to, and supported on, the bracket 15 via a link member 16. [0010] A single-cylinder four-cycle engine E is horizontally mounted at a front portion of the swing unit 2. A belt type continuously variable transmission 10 is formed rearwardly from the engine E. A rear wheel RW is journaled on reduction gearing 9 disposed via a centrifugal clutch on a rear portion of the continuously variable transmission 10. A rear suspension 3 is interposed between an upper end of the reduction gearing 9 and an upper portion bent portion of the main pipe 7. A carburetor 17 and an air cleaner 14 are disposed at a front portion of the swing unit 2. The carburetor 17 is connected to an intake pipe 19 extending from the engine E. The air cleaner 14 is connected to the carburetor 17. A kick pedal 4 is connected to a crankshaft of the engine E. [0011] FIG. 2 is a cross sectional view showing the swing unit 2, taken on surface A-A of FIG. 1. FIG. 3 is an enlarged cross sectional view taken along line B-B of FIG. 2. FIG. 4 is an enlarged cross sectional view taken along line C-C of FIG. 2. [0012] The swing unit 2 includes as its main components the engine E, a generator unit G, and an automatic transmission. The engine E is located forward in the vehicle. The generator unit G is connected to one end of a crankshaft 30. A drive unit AT1 of the automatic transmission is connected to the other end of the crankshaft 30. The automatic transmission also includes a driven unit AT2 driven by the drive unit AT1. As shown in FIG. 3, the swing unit 2 is mounted in a horizontal position to the vehicle body frame, in which an intake valve 38 is located upward of an exhaust valve 39. Though omitted in the figures, the swing unit 2 is mounted with an auto decompression device. The exhaust valve 39 is kept in a slightly opened position by making use of the phenomenon, in which the engine rotates backward immediately before stopping. [0013] The crankshaft 30 is rotatably supported by main bearings 33, 34. A connecting rod 31 is connected to the crankshaft 30 via a crankpin 35. A sprocket 59 is in a splined connection to the crankshaft 30. A chain 60 for deriving power for driving a camshaft 69 is wound around the sprocket 59. A generator 44 is disposed on one end of the crankshaft 30 jutting out from a crank chamber 36. [0014] A piston 63 disposed in a cylinder 62 is connected to a small end of the connecting rod 31. A spark plug 43 is screwed in a cylinder head 32. An electrode portion of the spark plug 43 faces a combustion chamber formed between a head of the piston 63 and the cylinder head 32. The cylinder 62 is surrounded by a heat radiating fin 71. The camshaft 69 is rotatably supported upward of the cylinder 62. A cam sprocket 72 is secured to the camshaft 69. The aforementioned chain 60 is wound around the cam sprocket 72. The chain 60 transmits rotation of the sprocket 59, i.e., rotation of the crankshaft 30. [0015] A rocker arm 73 is disposed on an upper portion of the camshaft 69. The rocker arm 73 is swung according to the shape of a cam on the camshaft 69 as the camshaft 69 rotates. The shape of the cam on the camshaft 69 is determined such that the intake valve 38 and the exhaust valve 39 open and close as required according to a predetermined stroke of the four-cycle engine. An auto decompression device not shown is provided for the camshaft 69. The auto decompression device keeps the exhaust valve 39 open for one revolution of the camshaft 69 after the exhaust valve 39 has been opened, i.e., for the period of time until the next cycle starts. [0016] A pulley 75, around which a V-belt 74 is wound, is disposed on the other end of the end, on which the generator 44 is disposed, of the crankshaft 30. The pulley 75 includes a fixed pulley piece 75a and a movable pulley piece 75b. The fixed pulley piece 75a is fixed in the rotating and axial directions relative to the crankshaft 30. The movable pulley piece 75b is supported axially slidably relative to the crankshaft 30. [0017] A holder plate 76 is attached to a back surface of the movable pulley piece 75b, i.e., the surface not in contact with the V-belt 74. The movement of the holder plate 76 is restricted both in the rotating and axial directions relative to the crankshaft 30. The holder plate 76 therefore rotates integrally with the crankshaft 30. A dead space enclosed by the holder plate 76 and the movable pulley piece 75b forms a pocket for accommodating a roller 77 serving as a governor weight. A fan 75c is integrally formed on a back surface of the fixed pulley piece 75a, i.e., the surface not in contact with the V-belt 74. When the crankshaft 30 turns in a normal direction, an outside air is drawn into an automatic transmission chamber through an intake port 70. [0018] A fixed pulley piece 52a of a pulley 52 is supported on a main shaft 51 of a clutch in the driven unit AT2 of the automatic transmission. A cup-shaped clutch plate 54 is fixed to an end portion of the main shaft 51 with a nut 53. A movable pulley piece 52b of the pulley 52 is mounted on a sleeve 55 of the fixed pulley piece 52a longitudinally slidably along the main shaft 51 The movable pulley piece 52b is engaged with a disk 56 so as to be rotated integrally about the main shaft 51. A compression coil spring 57 is disposed between the disk 56 and the movable pulley piece 52b. The compression coil spring 57 exerts a repulsion force in a direction extending a distance between the disk 56 and the movable pulley piece 52b. The main shaft 51, an idle shaft 58, and an output shaft 79 are mutually engaged with each other. The rear wheel RW is journaled on the output shaft 79. [0019] Referring to FIG. 4, an input gear 48 of a starter pinion 47 is engaged with a rotary shaft 46 of a starter motor 45. The starter pinion 47 axially elongates and contracts according to a rotating speed of the input gear 48. When the speed of the input gear 48 is equal to or greater than a predetermined level, an output gear 49 elongates axially to be engaged with the fixed pulley piece 75a. A driving force of the starter motor 45 is thereby transmitted to the crankshaft 30. When the speed of the input gear 48 becomes less than a predetermined level, the output gear 49 contracts axially to be disengaged from the fixed pulley piece 75a. As a result, the phenomenon, in which the engine rotates backward immediately before stopping, is not inhibited by the starter motor 45 and the starter pinion 47. [0020] FIG. 5 is a block diagram showing configuration of a principal part of the engine starting control apparatus according to the present invention. Like reference numerals represent like parts as those used in FIGS. 1 to 4. An exemplary case in which the present invention is applied to the engine with a carburetor has been described with reference to FIG. 3. The description that follows will be made referring to an exemplary case, in which the present invention is applied to an engine including a fuel injection valve. [0021] A battery 65 is connected via a starter relay 64 to an ECU 80. A drive current is supplied from the battery 65 to an injector 85, a fuel pump 86, and an ignition device 87 via a main fuse 66 and a main switch 67. The ignition device 87 detects an ignition timing based on a pulser signal detected by a pulser unit 42. Each time the ignition timing arrives, the ignition device 87 urges an ignition coil 41. The pulser unit 42 includes a pulser 42b and a magnetic pickup 42a. The pulser 42b is mounted on the crankshaft 30. The magnetic pickup 42a is disposed opposingly to the pulser 42b. Various sensors and switches are also connected to the ECU 80. These sensors and switches include an Ne sensor 81, a Tw sensor 82, a throttle opening sensor 83, a vehicle speed sensor 84, and a starter switch 88. The Ne sensor 81 detects an engine speed. The Tw sensor 82 detects an engine coolant temperature Tw. The throttle opening sensor 83 detects a throttle opening 9th. The vehicle speed sensor 84 detects a vehicle speed V. The starter switch 88 starts the starter motor 45. [0022] FIG. 6 is a functional block diagram of the ignition device 87. The ignition device 87 includes an ignition signal generator 87b, a misfire control unit 87a, and a logical product output unit 87c. The ignition signal generator 87b detects the ignition timing based on a pulse signal output from the magnetic pickup 42a and generates a first ignition signal P1. The misfire control unit 87a outputs an ignition prohibition signal P2 only for a predetermined period of time during engine starting. The logic product output unit 87c outputs a logical product of the aforementioned signals P1, P2 as a second ignition signal. [0023] The operation of the engine starting control apparatus according to the preferred embodiment of the present invention will be described with reference to a flowchart. FIG. 7 is a flowchart showing steps of "starting misfire control" relating to the present invention. FIG. 8 is a timing chart for the operation. [0024] In step S1, the starter relay 64 is monitored for detecting an operation to start the engine attempted by the starter motor 45. Referring to FIG. 8, the starter switch 88 is turned on at a time t1 and, in response to this event, the starter relay 64 is energized at a time t2. The energization of the starter relay 64 is detected in step S1. Then, the operation proceeds to step S2. Specifically, the "starting misfire control" is executed only when the engine is started by the starter motor. The control is not executed during kick starting. [0025] In step S2, it is determined whether or not the engine is in a state of complete explosion based on the engine speed. If it is determined that the engine is not in the state of complete explosion, the operation proceeds to step S3. Then in step S3, the initial value "2" of the misfire count is set in a misfire counter Nstop of the misfire control unit 87a. In step S4, the misfire control unit 87a outputs the ignition prohibition signal P2. In step S5, it is determined whether or not it is an ignition timing. [0026] When the first ignition timing arrives at a time t3 of FIG. 8, the ignition signal generator 87b outputs the first ignition signal P1. According to the preferred embodiment of the present invention, however, the second ignition signal P3 is not output since the ignition prohibition signal P2 is being outputted. As a result, ignition is prohibited and the engine misfires. In step S6, the operation is set into a standby state for a predetermined period of time in order to prohibit ignition immediately following a misfire. As the period of time for the standby state, 50 ms is set according to the preferred embodiment of the present invention. In step S7, the misfire counter Nstop is decremented. In step S8, it is determined whether or not the misfire counter Nstop is "0." Since the counter Nstop is "1" at first, the operation returns to step S5 and prepares for the next ignition timing. [0027] When a second ignition timing is thereafter detected at a time t4, the operation enters the standby state for the predetermined period of time in step S6 as before. The operation then proceeds to step S7, in which the misfire counter Nstop is decremented. Accordingly, the engine misfires again at the second ignition timing. [0028] In step S8, it is determined whether or not the misfire counter Nstop is "0." It is determined, herein, that the counter Nstop is "0" and the operation proceeds to step S9. In step S9, an output of the ignition prohibition signal P2 is stopped and the operation is thereafter terminated. Accordingly, if a third ignition timing is detected at a time t5, the second ignition signal P3 is outputted, thus firing the engine. [Description of the Reference Numerals] [0030] 2: Swing unit 30: Crankshaft 38: Intake valve 39: Exhaust valve 44: Generator 45: Starter motor 47: Starter pinion 69: Camshaft 73: Rocker arm 74: V-belt 75: Pulley We claim: 1. A control apparatus (80) for starting an engine (E) having an intake valve (38) mounted in a position upward of an exhaust valve (39) and including also a kick pedal and a starter motor (45), the control apparatus comprising: a decompression device opening the exhaust valve while the engine (E) remains stationary; an ignition device (87) firing the engine E at a predetermined timing; characterized by: a misfire device (87a) causing the engine to misfire by immobilizing the ignition device, wherein the misfire device (87a) is designed to let the engine (E) misfire only for a predetermined period of time while the engine is started using the starter motor (45). 2. The control apparatus as claimed in claim 1, further comprising reduction gearing (47, 48) for connecting the starter motor to the engine, wherein the reduction gearing disconnects the starter motor (45) from the engine (E) when the starter motor (45) runs at a predetermined speed range. 3. The control apparatus claimed in claim 1, wherein the misfire device (87a) causes the ignition device (87) to misfire two consecutive times while the engine E is started using the starter motor (45).

Documents:

81-del-2005-abstract.pdf

81-del-2005-claims.pdf

81-del-2005-correspondence-others.pdf

81-del-2005-correspondence-po.pdf

81-del-2005-description (complete).pdf

81-del-2005-drawings.pdf

81-del-2005-form-1.pdf

81-del-2005-form-18.pdf

81-del-2005-form-2.pdf

81-del-2005-form-3.pdf

81-del-2005-form-5.pdf

81-del-2005-gpa.pdf

81-del-2005-petition-137.pdf

81-del-2005-petition-138.pdf