Intake amount control apparatus of engine

Abstract: Problem To achieve a reduction in intake resistance in an intake amount control apparatus having a throttle body such that in a fully open state of the throttle valve, the valve is not present in an intake path of the throttle body. Solution A throttle body 11 is provided with a fitting hole 18 having a diameter larger than a diameter of an intake path 12 and orthogonal to an axial line X of the intake path 12, the fitting hole 18 is fitted with a rotary type throttle valve 20 for rotationally moving between a fully closed position and a fully open position and the throttle valve 20 is provided with a valve hole 27 coinciding with the intake path 12 at the fully open position.

Description: Field of the Invention The present invention relates to an improvement of an intake amount control apparatus of an engine comprising a throttle body having an intake path communicating with an intake port of an engine and a throttle valve provided at the intake path for adjusting an intake amount of the engine. Prior Art Such an intake amount control apparatus of an engine has already been known as disclosed in, for example, Japanese Patent Laid-open No.47520/1998. Problems to Be Solved by the Invention Conventionally, according to such an intake amount control apparatus of an engine, there is used a throttle valve of a butterfly type constituted by fixedly attaching a thin plate of a valve plate arranged in an intake path to a valve shaft penetrating the intake path in a throttle body in a transverse direction. In the case of such a constitution, a valve shaft having a diameter larger than a plate thickness of the valve plate is present in the intake path even in a fully opened state of the throttle valve in which the valve plate is in parallel with an axial line of the intake path. An increase in intake resistance thereby is unavoidable and an output property of the engine is affected more or less. Further, it is extremely difficult in view of fabrication accuracy to bring about the fully closed state in which the valve plate is completely brought into close contact with an inner peripheral face of the intake path over a total periphery thereof, further, when such a state is brought about, there is a concern in which the valve plate bites an inner face of the intake path and fixed attachment is caused. As a result, there is brought about a state in which the valve plate is slightly opened at a position of closing the throttle valve. However, there is a dispersion in view of the fabrication accuracy in such a very small opening degree of the valve plate and therefore, when there is provided idling adjusting means to a bypass connected to the intake path by detouring the throttle valve for controlling to open and close the bypass to thereby adjust an intake amount for idling, there is produced a considerable dispersion in an amount of adjusting thereof. In view of such a situation document JP-A-11141402 provides an intake amount control apparatus of an engine in which in an fully open state of a throttle valve, the valve is not present in an intake path of a throttle body to thereby enable to contribute to a reduction in intake resistance. Accordingly, an output property of the engine is improved to thereby enable to fully close the throttle valve without causing fixed attachment of the throttle valve. In order to achieve the above-described object, document JP-A-11141402 provides an intake amount control apparatus of an engine comprising a throttle body having an intake path communicating with an intake port of an engine and a throttle valve provided at the intake path for adjusting an intake amount of the engine, wherein the throttle body is provided with a fitting hole having a diameter larger than a diameter of the intake path and orthogonal to an axial line of the intake path, the fitting hole is fitted with the throttle valve of a rotary type rotationally moving between a fully closed position and a fully open position and the throttle valve is provided with a valve hole coinciding with the intake path at the fully open position. According to there characteristics, a state in which the rotary type throttle valve is fitted to the fitting hole of the throttle body remains unchanged from the fully closed state to the fully open state. Even at the fully closed position, there is no concern of fixed attachment as in the conventional butterfly type throttle valve. Further, when operating the engine, by an operation of intake negative pressure thereof, the throttle valve is drawn to the downstream side of the intake path and is brought into close contact with one side of the fitting hole. Therefore, leakage of air from the fitting hole is hampered and an excellent fully closed state of the throttle valve can be provided. Further, when the throttle valve is brought into the fully open state, the valve hole coincides with the intake path, a continuous intake path is formed such that nothing is present in the intake path and therefore, the intake resistance of the intake path is considerably reduced, resulting in the high output property of the engine. Further, since the throttle valve is of the rotary type, a mutual contact area of the valve and the throttle body is wide and accordingly, heat radiating and heat receiving property thereof is excellent. Furthermore, in addition to these characteristics, and according to the present invention there is provided an auxiliary intake path opened to the valve hole over the throttle body and the throttle valve. According to this additional characteristic, a portion of the auxiliary intake path is formed at the throttle valve and accordingly, formation of the auxiliary intake path to the throttle body is reduced and molding of the throttle body with the auxiliary intake path can be carried out easily. Further, a first optional feature of the present invention resides in that the throttle body is made of a synthetic resin. According to the first optional feature, friction coefficient of an inner face of the fitting hole of the throttle body is lowered and rotation, that is, opening and closing of the throttle valve fitted to the fitting hole can be carried out lightly. Further, a second optional feature of the present invention resides in that the rotary type throttle valve is made of a synthetic resin. According to the second optional feature, friction coefficient of a rotational face of the throttle valve is lowered and rotation, that is, opening and closing of the throttle valve relative to the throttle body can be carried out lightly. Further, a third optional feature of the present invention resides in that the throttle valve is directly connected with a rotor of a throttle sensor for detecting an opening degree thereof. According to the third optional feature, the opening degree of the throttle valve can be detected accurately by the throttle sensor. Furthermore, a fourth optional feature of the present invention resides in that a direction of opening the throttle valve is constituted so that a lower portion thereof is directed to a downstream side of the intake path. According to the fourth optional feature, when the throttle valve is at an intermediate opening degree, a lower portion of the fitting hole of the throttle body is exposed to the intake path and even when fuel is going to store at the lower portion of the fitting hole by blow back of intake gas, air which has flowed in from an inlet of the intake path is obliquely lowered in a valve hole and flows along with the fuel to the downstream side of the intake path along a bottom face of the fitting hole. Accordingly, the fuel can be prevented beforehand from being stored at the lower portion of the fitting hole, an influence of the mixture gas on a variation in an air-fuel ratio can be avoided. Brief Description of the Drawings An explanation will be given of a mode for carrying out the invention based on an embodiment of the present invention shown in attached drawing in which : Fig.1 is a vertically sectional side view of an engine having an intake amount control apparatus according to a first embodiment of the present invention. Fig.2 is a side view of the intake amount control apparatus according to the present invention. Fig.3 is a sectional view taken along a line 3-3 of Fig.2. Fig.4 is a disassembled view in correspondence with Fig.3. Fig.5 is a sectional view taken along a line 5-5 of Fig.3. Fig.6 is a sectional view taken along a line 6-6 of Fig.3. Fig.7 is a sectional view taken along a line 7-7 of Fig.3. Fig.8 illustrates explanatory views for explaining operation of a throttle valve. Fig.9 is characteristic line diagram of the intake amount control apparatus according to the present invention. Fig.10 illustrates sectional views in correspondence with Fig.8 showing a second embodiment of the present invention. Fig.11 illustrates sectional views in correspondence with Fig.8 showing a third embodiment of the present invention. Mode for Carrying Out the Invention Fig.1 through Fig.9 show a first embodiment of the present invention, Fig.1 is a vertically sectional side view of an engine having an intake amount control apparatus according to the present invention, Fig.2 is a side view of the intake amount control apparatus according to the present invention, Fig.3 is a sectional view taken along a line 3-3 of Fig.2, Fig.4 is a disassembled view in correspondence with Fig.3, Fig. 5 is a sectional view taken along a line 5-5 of Fig.3, Fig. 6 is a sectional view taken along a line 6-6 of Fig.3, Fig.7 is a sectional view taken along a line 7-7 of Fig.3, Fig.8 illustrates explanatory views for explaining operation of a throttle valve and Fig.9 is a characteristic line diagram of the intake amount control apparatus according to the present invention. Further, Fig.10 illustrates sectional views in correspondence with Fig.8 showing a second embodiment of the present invention and Fig.11 illustrates sectional views in correspondence with Fig.8 showing a third embodiment of the present invention. Firstly, the explanation will be started by explaining the first embodiment of the present invention. In reference to Fig.1, an engine E is a 4 cycle engine for a motorcycle and is provided with a cylinder block 1 and a cylinder head 2 taking substantially a horizontal attitude directing the head portion to a front direction of the vehicle and the cylinder head 2 is provided with an intake port 3, an exhaust port 4, an intake valve 5, an exhaust valve 6 and a vale moving mechanism 7 for driving to open and close these valves. An intake pipe 8 communicating with the intake port 3 is coupled to an upper face of the cylinder head 2. The intake pipe 8 is made of synthetic resin and an electromagnetic type injection valve 9 is attached to a supporting boss 8c formed at a side thereof by a valve holder 91. Injected fuel from the fuel injection valve 9 is directed to the intake port 3 of the cylinder head 2 by a fuel delivery hole 86 formed at the intake pipe 8. The valve holder 91 is constituted by molding a first holding cylinder portion 91a fitted to a base portion of the fuel injection valve 9, a second holding cylinder portion 91b fitted to a front end portion of the valve 9 having a fuel inlet, a connecting portion 91c for integrally coupling the two holding cylinder portions 91a and 91b and a hose joint 92 projected from one side of the second holding cylinder portion 91b integrally by synthetic resin and the first holding cylinder portion 91a is embedded with a metallic ring 93 coupled to the supporting boss 8c. The hose joint 92 is connected with a fuel hose 94 communicating with a fuel injection pump, not illustrated. An intake amount control apparatus 10 is connected to an upstream end of the intake pipe 8 mounted with the fuel injection valve 9. That is, the intake amount control apparatus 10 is arranged upstream from the fuel delivery hole 96 in an intake system of the engine E. An explanation will be given of the intake amount control apparatus 10 in reference to Fig.1 through Fig.3. The intake amount control apparatus 10 is provided with a throttle body 11 made of synthetic resin, (for example, made of PPS). The throttle body 11 is provided with an intake path 12 of which downstream side is inclined slightly downwardly, a diameter of an upstream end portion thereof is enlarged in a funnel-like shape and an inner peripheral face of a downstream end portion thereof is formed with a ring-like recess portion 13a. The upstream end portion of the intake path 12 in the funnel-like shape is connected with an air cleaner (not illustrated) via an intake duct 95 made of rubber. In this case, when the intake duct 95 and a case main body of the air cleaner are also made of synthetic resin and these are integrally molded along with the throttle body 11, simplification of the constitution can be achieved. In this case, compact formation of the constitution can also be achieved by arranging the throttle body 11 in the air cleaner. Further, the throttle body 11 is provided with a straight path 33 of an auxiliary intake path 12, mentioned later, opened to a downstream side end face thereof in parallel with the intake path 12 and a ring-like recess portion 13b is formed also at an inner peripheral face of a downstream end portion of the straight path 33. In the meantime, the intake pipe 8 is provided with an intake path 8a for communicating the intake path 12 with the intake port 3 of the engine E and an auxiliary intake path 8b for communicating with a supercharging pump 36 driven by the engine E, a pair of fitting cylindrical portions 26a and 26b are formed at an upstream end portion of the intake pipe 8 in correspondence with the intake path 8a and the auxiliary intake path 8b and these are fitted to the ring-like recess portions 13a and 13b respectively via seal members 14a and 14b. The throttle body 11 and the intake pipe 8 are formed with connecting flanges 15 and 16 which are brought into contact with each other and these are coupled with each other by a connecting ring 17 having a section in a U shape. In this way, the throttle body 11 is connected to the intake pipe 8. At this occasion, the seal members 14a and 14b mounted to respective outer peripheries of the fitting cylindrical portions 26a and 26b of the intake pipe 8 are brought into close contact with inner peripheral faces of the ring-like recess portions 13a and 13b of the throttle body 11 to thereby maintain airtightness between inner portions of the throttle body 11 and the intake pipe 8. While eliminating finish machining of respective end faces of the two connecting flanges 15 and 16, not only the airtightness between the throttle body 11 and the intake pipe 8 can be ensured, but also thin wall formation of the two flanges 15 and 16 is made feasible and compact formation of these connecting portions can be achieved. As shown in Fig.2 through Fig.4, the throttle body 11 is provided with a fitting hole 18 having a diameter larger than the diameter of the intake path 12 orthogonally to an axial line X of the intake path 12 and a throttle valve 20 of a rotary type is rotatably fitted to the fitting hole 18. The throttle valve 20 is also made of a synthetic resin (for example, made of 6/6 nylon) . A flange 21 is formed at one end of the throttle valve 20 and the flange 21 is sandwiched by a stepped portion 22 of the throttle body 11 and a stopper ring 23 locked to the throttle body 11, thereby, a position of the throttle valve 20 in an axial direction is specified. The throttle body 11 is formed with a ring-like groove 24 contiguous to the flange 21 and the ring-like groove 24 is mounted with a seal member 25 in close contact with an outer peripheral face of the throttle valve 20. Further, the throttle valve 20 is formed with a valve hole 27 having a section which is the same as a section of the intake path 12, at the fully closed position of the throttle valve 20 (refer to Fig.7(A)), the valve hole 27 completely crosses the intake path 12 to thereby produce an unflowable state and at the fully open position (refer to Fig.7 (C)), the valve hole 27 coincides with the intake path 12 to thereby form the continuous intake path 12. One end of the throttle valve 20 is integrally molded with a drive drum 39 having a wire groove 38 at an outer periphery thereof, one end of an operating wire 30 engaged with the wire groove 38 is connected to the drive drum 39 and other end thereof is connected to a throttle grip of a steering handle, not illustrated. When the operating wire 30 is pulled by rotating the throttle grip, the throttle valve 20 can be rotated from the fully closed position to the fully open position. The throttle valve 20 is formed with a vertical hole 31 reaching the valve hole 27 from other end face thereof and a horizontal hole 32 penetrating a side wall of the vertical hole 31 and the throttle body 11 is formed with the straight path 33 communicating with the vertical hole 32 and opened to the upstream side end face of the throttle body 11. An auxiliary intake path 34 is constituted of the vertical hole 31, the horizontal hole 32 and the straight path 33. As described above, the auxiliary intake path 34 is connected to the supercharging pump 36 via the auxiliary intake path 8b of the intake pipe 8. The other end face of the throttle valve 20 is welded with a cap 38 made of a synthetic resin for closing an opening portion of the vertical hole 31 and the cap 38 is integrally molded with a connecting shaft 39 having a section of a chipped circle and extended coaxially with the throttle valve 20. The connecting shaft 39 is fitted with a connecting cylinder 41 of a rotor 40r of a throttle sensor Sth for detecting the opening degree of the throttle valve 20. Further, when the throttle body 11 is not provided with the auxiliary intake path 8b, the connecting shaft 39 can be molded integrally with the throttle valve 20. As shown in Fig.3 and Fig.6, a front end of the connecting cylinder 41 is formed with slits 42 for providing diameter contracting elasticity to thereby enable to fit to the outer peripheral face of the connecting shaft 39 without play. An intermediary between the rotor 40r and throttle body 11 is connected with a return spring 37 comprising a torsional coil spring for urging the throttle valve 20 in a direction of closing thereof via the rotor 40r. Therefore, the return spring 37 constitutes a return spring common to the throttle valve 20 and the rotor 40r. The throttle body 11 is integrally molded with a control unit attaching portion 43 in a tray-like shape and an electronic control unit U is attached thereto. The electronic control unit U is constituted of a sensor board 44 which is opposed to a bottom face of the control unit attaching portion 43, an element board 45 arranged to overlap a rear face of the sensor board 44 and a unit housing 46 for containing these boards 44 and 45. The sensor board 44 is provided with a supporting hole 49 rotatably fitted with a central shaft 48 of the rotor 40r of the throttle sensor Sth and is formed with a stator 40s for converting a rotational angle of the rotor 40r, that is, the opening degree of the throttle valve 20 into an electric signal via brushes 50. Further, the sensor board 44 is attached with a boost negative pressure sensor Spb. The boost negative pressure sensor Spb detects boost negative pressure of the engine E, in other words, engine load via a detecting hole 47 opened to the intake path 12 downstream the throttle valve 20 and converts the detected boost negative pressure to an electric signal. Further, according to the throttle sensor Sth, the brushes 50 can also be provided to the side of the stator 40s by switching opposed faces of the rotor 40r and the stator 40s. Further, the throttle sensor Sth can also be constituted in a noncontact type by using a Hall element and a magnet. Further, a male connection terminal 51a is projected at a lower face of the sensor board 44 and a female connection terminal 51b connected thereto is provided at the bottom face of the control unit attaching portion 43. The female connection terminal 51b is connected with a lead wire 52 communicating with an intake temperature sensor St facing an inlet of the intake path 12 of the throttle body 11. In molding the throttle body 11, the intake temperature sensor St, the lead wire 52 and the female connection terminal 51b are embedded therein. Thereby, wiring operation between the intake temperature sensor St and the electric control unit U can be eliminated. A female connection terminal 80b communicating with the stator 40s of the throttle sensor Sth, the boost negative pressure sensor Spb, the male connection terminal 51a and the like, is embedded at an upper face of the sensor board 44. The element board 45 is added with an LED indicator 84 used for a test of the electronic control unit U and failure alarm other than a male connection terminal 80a connected to the female connection terminal 80b, an element 81 for fuel injection amount control, an element 82 for fuel injection timing control, an element 83 for ignition timing control and other various control elements which communicate with the male connection terminal 80a, and is molded to couple to the unit housing 46 along with these. In this way, there is no need of providing the indicator 84 at a special instrument panel or the like and the wiring therefor is not needed. A coupler housing 85 is integrally formed with one side of the unit housing 46, at inside thereof, a plurality of coupler terminals 86 communicating with these respective elements (only one of them is shown in the drawings) to thereby constitute a coupler half 87a. Thereby, when the electronic control unit U is integrally provided with the coupler half 87a, wiring operation therebetween is eliminated and a reduction in a number of parts can be achieved. The coupler half 87a is connected with other coupler half 87b having connection terminals communicating with the outside power supply, various sensors of an engine rotational number sensor Sne, a crank position sensor Sc and the like as well as various control apparatus of an ignition timing control device Ig and the like. Although the fuel injection amount control element 81 and the fuel injection timing control element 82 may be connected to a solenoid of the electromagnetic fuel injection valve 9 via the coupler halves 87a and 87b to thereby operate the solenoid, in the case of the illustrated example, lead wires 88 and 89 for connecting output portions of the fuel injection amount control element 81 and the fuel injection timing control element 82 to the solenoid of the fuel injection valve 9, are embedded in the throttle body 11 and the intake pipe 8. In that case, coupling faces of the throttle body 11 and the intake pipe 8 are respectively provided with a female connection terminal 90b and a male connection terminal 90a for connecting the two lead wires 88 and 89 and a pair of connection terminals similar thereto are also provided at coupling faces of the intake pipe 8 and the fuel injection valve 9. Thereby, electric connection can be carried out simultaneous with assembling parts, which can contribute to promotion of assembling property and reduction of a number of parts. Further, when the throttle body 11 and the intake path pipe 8 are integrally molded by synthetic resin, the connection terminals are also eliminated and a further reduction in the number of parts can be achieved. Further, in attaching the electronic control unit U to the throttle body 11, the sensor board 44 is previously made to overlap the lower face of the element board 45 and the connection terminals 80a and 80b are connected to each other. Further, when the unit housing 46 is fitted to the control unit attaching portion 43 of the throttle body 11 in socket and spigot joint, the connection terminals 51a and 51b of the sensor board 44 and the throttle body 11 are connected to each other and under the state, faces of the unit housing 46 and the control unit attaching portion 43 in contact with each other are welded. Further, the unit housing 46 and the control unit attaching portion 43 can also be coupled separably from each other by clips, screws-or the like. Thereby, maintenance and check of inside of the electronic control unit U is made possible. In reference to Fig.3 and Fig.7, the throttle body 11 is provided with a bypass 53 for connecting both ends thereof to the intake path 12 by detouring the throttle valve 20 and the throttle body 11 is attached with a fast idling device 55 for making a piston type valve member 54 face the bypass 53. The throttle body 11 is provided with a valve guide hole 56 to which the valve member 54 is slidably fitted, an inlet chamber 57 opened to an end face of the valve guide hole 56 and an outlet chamber 58 communicating with a side face of the valve guide hole 56 via a plurality of small holes 59 extended in a sliding direction of the valve member 54. The bypass 53 is constituted of a bypass upstream portion 53a connected to the upstream side of the intake path 12 and a bypass downstream portion 53b connected to the downstream side of the intake path 12, a downstream end of the bypass upstream portion 53a is connected to the inlet chamber 57 and an upstream end of the bypass downstream portion 53b is connected to the outlet chamber 58. Further, when the valve member 54 is moved in the valve guide hole 56, an opening degree of a group of the small holes 59 is adjusted by a side face of the valve member 54 and by the opening degree of the group of small holes 59, an amount of intake flowing in the bypass 53 is determined. The fast idling device 55 is constituted of the valve member 54 and temperature sensitive operating means 60 for operating the valve member 54 in accordance with temperature change of the engine E. The temperature sensitive operating means 60 is constituted of a housing 62 fitted and fixed to an attaching hole 61 of the throttle body 11, a wax holder 63 having a shape of a bottomed cylinder fittedly mounted to inside of the housing 62, a wax case 65 fitted to and held by the wax holder 63 and filled with wax 64 at inside thereof, an output rod 68 which is slidably fitted to a bearing 66 at one end portion of the wax case 65, an end of which is opposed to the wax 64 via a seal piston 67 and other end of which is projected outside of the wax case 65, an operating member 69 having a shape of a bottomed cylinder slidably fitted to the outer periphery of the wax case 65 while an inner end face thereof being brought into contact with a front end of the output rod 68, a return spring 70 for urging the operating member 69 to the side of the output rod 68 and an electric heater 71 attached to the wax holder 63. The electricity is conducted to the electric heater 71 after starting the engine E and the wax 64 is heated in correspondence with elevation of engine temperature. The operating member 69 is integrally provided with a connecting shaft 74 coaxially aligned with the output rod 68 at an outer end face thereof and the connecting shaft 74 is slidably fitted to a bottomed connecting hole 75 formed at an end face of the valve member 54 on a side opposed to the inlet chamber 57. A front end of the connecting shaft 74 is formed with an outwardly directed flange 74a and an opening end of the connecting hole 75 is formed with an inwardly directed flange 75a, respectively. By bringing the two flanges 74a and 75a in contact with each other, a slidable movement limit of the connecting shaft 74 and the valve member 54 in an elongating direction is specified. Between the connecting shaft 74 and the valve member 54, there is contractedly provided a lost motion spring 76 for urging these in the elongating direction, or in the closing direction with regard to the valve member 54. Further, in cold time, when the wax 64 in the wax case 65 is brought into a shrunken state, by load of the return spring 70, the operating member 69 is retracted such that the operating member 69 pushes the output rod 68 into the wax case 65 and when the wax 64 is expanded by heating by the heater 71, the output rod 68 is operated to move forward the operating member 69 to the side of the valve member 54 against the load of the return spring 70. Therefore, the valve member 54 increases the opening degree of the group of small holes 59 in shrinking the wax 64 and reduces the group of small holes 59 in accordance with expansion of the wax 64. Further, the throttle body 11 is provided with movable stopper means 77 capable of adjusting a position of closing and stopping the valve member 54. The movable stopper means 77 is constituted of a stopper bolt 78 screwed to the throttle body 11 to be opposed to the end face of the valve member 54 by penetrating the inlet chamber 57 and a helical spring 79 sandwiched between the head portion of the stopper bolt 78 and the throttle body 11 for preventing blind movement of the stopper bolt 78. Next, an explanation will be given of operation of the embodiment. In starting and idling the engine E, as shown in Fig.8 (A), the throttle valve 20 is set to the fully closed position at which the valve hole 27 and the intake path 12 completely cross to each other. The throttle valve 20 is of the rotary type, a state of fitting the throttle valve 20 to the fitting hole 18 of the throttle body 11 is always constant. Even at the fully closed position, there is no concern of fixed attachment as in the conventional butterfly type throttle valve. Further, in operating the engine E, by operation of the intake negative pressure, the throttle valve 20 is drawn to the downstream side of the intake path 12 and is brought into close contact with one side of the fitting hole 18. Accordingly, leakage of air from the fitting hole 18 is prevented and the fully closed state of the throttle valve 20 is provided. In the meantime, at cold time, in the fast idling adjusting device 55, the wax 64 is contracted and therefore, the operating member 69 is disposed at the retracted position by load of the return spring 70. Under the state, the connecting shaft 74 of the operating member 69 and the valve member 54 are brought into a connecting state in which the outwardly directed flange 74a and the inwardly directed flange 75a are brought into contact with each other by load of the lost motion spring 76. Accordingly, the valve member 54 is maintained at a high opening degree position at which the group of small holes 59 is widely opened by the operating member 69. Hence, when the engine E is started in the fully closed state of the throttle valve 8, air is sucked into the engine E by passing through the bypass 53, the intake amount is controlled to a comparatively large amount by the group of small holes 59. The air and fuel injected from the fuel injection valve 9 are mixed, a comparatively large amount of rich mixture gas suitable for starting can be produced and starting of the engine E can be carried out with certainty. Further, even in a warming up state of the engine, as described above, the comparatively large amount of mixture gas is supplied to the engine E and accordingly, the engine E is provided with a fast idling rotational number and warming up thereof can be accelerated. As the warming up operation is progressed, the engine temperature is elevated, the heater 71 heats the wax 64 and therefore, the wax 64 is expanded and the operating member 69 is moved forward against the load of the return spring 70. In accordance therewith, the valve member 54 is pushed in the closing direction, the opening degree of the group of the small holes 59 is reduced, and the intake amount passing through the bypass 53 is reduced. As a result, the fuel injection amount is reduced in accordance therewith and the number of the fast idling rotation is lowered. Further, when the valve member 54 reaches a position in contact with the stopper bolt 78, that is, the close position, the opening degree of the group of small holes 59 is minimized and the intake amount is also minimized. By the minimum intake amount, the number of the normal idling rotation of the engine E is ensured. Therefore, when the stopper bolt 78 is adjusted to progress or regress to/from the valve member 54, the minimum intake amount can be adjusted by changing the close position of the valve member 54 to thereby enable to adjust the idling rotational number to a desired value. Further, since the adjustment of the minimum intake amount is carried out by adjusting the opening degree of the group of small holes 59 provided at the bypass 53 having a diameter far smaller than the diameter of the intake path 12, fine adjustment of the minimum intake amount can easily be carried out without the special skill. As described above, when the rotary type throttle valve 20 is maintained in the fully closed state, there is no dispersion of the adjustment amount of the fast idling device 55 and the stopper bolt 78 or the dispersion is significantly reduced and the stable fast idling state and a normal idling state of the engine E can be provided. Afterward, when the wax 64 is further expanded and the operation member 69 is further progressed, the connecting shaft 74 is deeply progressed into the connecting hole 75 of the valve member 54 while compressing the lost motion spring 76 and accordingly, while maintaining the valve member 54 at the predetermined close position, excessive expansion of the wax 64 is absorbed by the lost motion spring 76 and occurrence of excessive stress can be avoided. Further, when the valve member 54 is operated by a linear solenoid in place of the wax 64, the idling control can be carried out further finely. When the operating wire 30 is pulled and the throttle valve 20 is rotated in the valve opening direction in order to increase output of the engine E, the valve hole 27 of the throttle valve 20 emerges on the intake path 12. The opening degree is increased, the intake amount of the engine E can be increased. At that occasion, as described above, the valve opening direction of the throttle valve 20 is constituted so that a lower portion thereof is directed to the downstream side of the intake path 12. As shown in Fig.8 (B), at an intermediate opening degree of the throttle valve 20, a lower portion of the fitting hole 18 of the throttle body 11 is exposed to the intake path 12, and even when fuel is going to store at the lower portion of the fitting hole 18 by blow back of intake gas, air which has flowed in from the inlet of the intake path 12 is obliquely lowered at the valve hole 27 and flows along with the fuel along the bottom face of the fitting hole 18. The fuel can be prevented beforehand from being stored at the lower portion of the fitting hole 18, and an influence of the mixture gas on a variation in an air-fuel ratio can be avoided. At this occasion, the bottom face of the valve hole 27 of the throttle valve 20 takes an attitude of an ascending slope directed to the downstream the intake path 12 and hampers transfer of the fuel to the downstream side with certainty. As shown in Fig.8 (C), when the throttle valve 20 is rotated to the fully open position, the valve hole 27 coincides with the intake path 12. The continuous intake path 12 is formed such that nothing is present in the intake path 12. The intake resistance of the intake path 12 is considerably reduced, resulting in high output property of the engine. Further, the fuel delivery hole 96 is arranged downstream the throttle body 11 and injected fuel from the fuel injection valve 9 is delivered to the intake port 3 therethrough. The fuel supply system does not constitute the intake resistance, which is particularly advantageous in fully closing the throttle valve 20, further, the fuel does not pass through inside of the throttle body 11. Accordingly, the adherence of the fuel on the pipe wall is restrained to the minimum and the variation in the air-fuel ratio can be prevented. During the time period, air delivered from the supercharging pump 36 is supplied to the engine E via the auxiliary intake path 34 and the charging efficiency is promoted, which contributes to further promotion of output. In the meantime, the auxiliary intake path 34 is provided over the throttle body 11 and throttle valve 20 such that the auxiliary intake path 34 is opened to the valve hole 27 and therefore, formation of the auxiliary intake path 34 in the throttle body 11 is reduced. Only the straight path 33 is formed and molding of the throttle body 11 with the auxiliary intake path 34 can be carried out easily. Next, when traction force exerted on the operating wire 30 is released, to reduce output of the engine E, the throttle valve 20 returns to the fully closed position by repulsive force of the return spring 37 and the engine E is brought into the idling state again. Further, both of the throttle body 11 and throttle valve 20 are made of synthetic resin. The frictional coefficient between rotational fitting faces of these is comparatively low, surface hardness thereof is comparatively low. The rotational faces of the throttle body 11 and throttle valve 20 are easy to be adaptable to each other at an early stage and accordingly, opening and closing of the throttle valve 20 can lightly be carried out and a leakage amount of air from the rotational faces can be stabilized at an early stage. Further, since the rotary valve 20 is of the rotary type, mutual contact faces of the throttle body 11 and throttle valve 20 are extremely wide, excellent heat radiating and heat receiving property can be provided. Since the mutual contact faces are wide, closing property of the throttle valve 20 at the fully closed position is improved, which can contribute to stabilization of idling of the engine E. Fig.9 is a characteristic line diagram showing a relationship between the throttle valve opening degree and the intake amount in the intake amount control apparatus 10 according to the present invention, showing that the characteristic can be changed by variously selecting the sectional shape of the intake path 12 and the valve hole 27 such as a shape of a circle, a shape of a triangle with rounded corners, a shape of an inversed triangle with rounded corners or the like. In operating such an engine E, the throttle sensor Sth in which the rotor 40r is directly connected to the throttle valve 20, can accurately detect the opening degree of the throttle valve 20. Further, the fuel injection amount control element 81, the fuel injection timing control element 82 and the ignition timing control element 83 in the electronic control unit 46, receive electric signals outputted from the throttle sensor Sth, the boost negative pressure sensor Spb, the intake temperature sensor St, the engine rotational number sensor Sne, the crank position sensor Sc and the like and determine the operating state of the engine at that time. The fuel injection amount control element 81 and the fuel injection timing control element 82 determine the fuel injection amount and the fuel injection timing of the fuel injection valve 9 and operate the valve 9 in accordance therewith. The ignition timing control element 83 determines the ignition timing and operates an ignition device, not illustrated, in accordance therewith. In the meantime, the sensor board 44 having the throttle sensor Sth and the boost negative pressure sensor Spb and the element board 45 having the fuel injection amount control element 81, the fuel injection timing control element 82 and the ignition timing control element 83, are contained in the single unit housing 46 to thereby constitute the electronic control unit U and are attached to the control unit attaching portion 43 of the throttle body 11. The various sensors Sth, Spb and the various control elements 81 through 83 are unitized, the unit can be installed compactly to the throttle body 11. Accordingly, there is no need of a space for installing the electronic control unit other than the throttle body 11, the improved space efficiency and the compact formation of the control system can be obtained, resulting in the compact formation of the intake apparatus. Not only simplification of wirings between the throttle sensor Sth and the various control elements 81 through 83 can be carried out, but also wiring integration of power supply codes necessary for operating the various control elements 81 through 83 and a signal line from the engine rotational number sensor Sne can also be achieved. Simplification of the wirings in this way is advantageous in view of reducing an influence of electromagnetic wave or the like. Further, the rotor 40r of the throttle sensor Sth is directly connected to the throttle valve 20 and therefore, the opening degree of the throttle valve 20 can accurately be detected. Further, since the various control elements 81 through 83 are arranged at the wide back face of the sensor board 44 via the element board 45, the various control elements 81 through 83 can freely be arranged without the interference of the throttle sensor Sth and the boost negative pressure sensor Spb and the degree of freedom of layout thereof is high. Further particularly, the sensor board 44 and the element board 45 are coupled to each other in the laminated state separably from each other and accordingly, the constitution is compact. There can be provided inexpensively the electronic control unit U having various characteristics by changing specifications of various sensors and elements attached on the sensor board 44 and the element board 45 in accordance with the kind of the apparatus. The throttle body 11 is made of synthetic resin and therefore, the throttle body per se is provided with insulating property. The electronic control unit U can be attached thereto without interposing a special insulating member therebetween and simplification of the attaching structure can be achieved. A second embodiment of the present invention shown in Fig.10 is provided with a constitution similar to that of the preceding embodiment except that the valve hole 27 of the rotary type throttle valve 20 is formed in a chipped shape in which one side thereof is opened upwardly when the valve is fully opened and in the drawing, portions corresponding to those of the preceding embodiment are attached with the same reference notations and an explanation thereof will be omitted. A third embodiment of the present invention shown in Fig.11 is provided with a constitution similar to that of the preceding embodiment except that a lower face of the rotary type throttle valve 20 is arranged to coincide with a bottom face of the intake path 12 of the throttle body 11 and the valve hole 27 is formed in a chipped shape such that one side thereof is opened downwardly when the valve is fully opened. In the drawing, portions corresponding to the preceding embodiments are attached with the same reference notations and an explanation thereof will be omitted. According to the third embodiment, the bottom face of the intake path 12 is not formed with a recess portion by the fitting hole 18 to which the throttle valve 20 is fitted and the fuel can be prevented from being stored. The present invention is not limited to the above-described respective embodiments but various design change can be carried out within a range not deviated from the gist. For example, only one of the throttle body 11 and the throttle valve 20 can be made of synthetic resin. Effect of the Invention As describe above, according to the first characteristic of the present invention, in an intake amount control apparatus of an engine comprising a throttle body having an intake path communicating with an intake port of an engine and a throttle valve provided at the intake path for adjusting an intake amount of the engine, the throttle body is provided with a fitting hole having a diameter larger than a diameter of the intake path and orthogonal to an axial line of the intake path, the fitting hole is fitted with the throttle valve of a rotary type rotationally moving between a fully closed position and a fully open position and the throttle valve is provided with a valve hole coinciding with the intake path at the fully open position. Accordingly, in the throttle body, the fitting state with the fitting hole of the throttle body remains unchanged from the fully closed state to the fully open state and there is no concern of fixed attachment even at the fully closed position. Further, in operating the engine, by operation of the intake negative pressure, the throttle valve is drawn to the downstream side of the intake path and is brought into close contact with one side of the fitting hole to thereby hamper leakage of air from the fitting hole. Therefore, the fully closed state of the throttle valve can be obtained. Further, when the throttle valve is brought into the fully open state, the valve hole coincides with the intake path, the continuous intake path is formed such that nothing is present in the intake path. The intake resistance of the intake path is considerably, resulting in the high output property of the engine. Since the throttle valve is of the rotary type, the mutual contact areas of the valve and the throttle body are wide and the heat radiating and heat receiving property is excellent. According to the second characteristic of the present invention, the throttle body is made of synthetic resin and therefore, the frictional coefficient of the inner face of the fitting hole of the throttle body is lowered and opening and closing of the throttle valve can be carried out lightly. Further, according to the third characteristic of the present invention, the rotary type throttle valve is made of synthetic resin and accordingly, the frictional coefficient of the rotational face of the throttle valve is lowered and opening and closing of the throttle valve can be carried out lightly. Further, according to the fourth characteristic of the present invention, the throttle valve is directly connected with the rotor of the throttle sensor for detecting the opening degree and accordingly, the opening degree of the throttle valve can be detected accurately by the throttle sensor. Further, according to the fifth characteristic of the present invention, the direction of opening the throttle valve is constituted so that the lower portion thereof is directed to the downstream side of the intake path. At an intermediate opening degree of the throttle valve, the lower portion of the fitting hole of the throttle body is exposed to the intake path, even when fuel is going to store at the lower portion of the fitting hole by blow back of the intake gas, air which has flowed in from an inlet of the intake path is lowered obliquely in the valve hole and flows along with the fuel to the downstream side of the intake path along the bottom face of the fitting hole and the fuel can be prevented beforehand from being stored at the lower portion of the fitting hole. As a result, an influence of mixture gas on a variation in an air-fuel ratio can be avoided. Further, according to the sixth characteristic of the present invention, there is provided the auxiliary intake path opened to the valve hole over the throttle body and the throttle valve and accordingly, formation of the auxiliary intake path in the throttle body is reduced and molding of the throttle body with the auxiliary intake path can be carried out easily.

Claims: An intake amount control apparatus of an engine, said apparatus comprising a throttle body (11) having an intake path (12) communicating with an intake port (3) of an engine (E) and a throttle valve (20) provided at the intake path (12) for adjusting an intake amount of the engine (E) : wherein the throttle body (11) is provided with a fitting hole (18) having a diameter larger than a diameter of the intake path (12) and orthogonal to an axial line (X) of the intake path (12), the fitting hole (18) is fitted with the throttle valve (20) of a rotary type rotationally moving between a fully closed position and a fully open position and the throttle valve (20) is provided with a valve hole (27) coinciding with the intake path (12) at the fully open position ; and wherein a direction of opening the throttle valve (20) is constituted so that a lower portion thereof is directed to a downstream side of the intake path (12), said apparatus being characterized in that it includes an auxiliary intake path (34) opened to a valve hole (27) over the throttle body (11) and the throttle valve (20). An intake amount control apparatus of an engine according to claim 1, characterized in that the throttle body (11) is made of a synthetic resin. An intake amount control apparatus of an engine according to anyone of claims 1 and 2, characterized in that the throttle valve (20) is made of a synthetic resin. An intake amount control apparatus of an engine according to anyone of claims 1 to 3, characterized in that the throttle valve (20) is directly connected with a rotor (40r) of a throttle sensor (40) for detecting an opening degree thereof.

Inventors: HAMAUZU AKIRA, IIMURO AKIHIRO, SUZUKI OSAMU, HAMAUZU, AKIRA, IIMURO, AKIHIRO, SUZUKI, OSAMU
Applicants: HONDA MOTOR CO LTD, HONDA GIKEN KOGYO KABUSHIKI KAISHA
Application year: 2000
Main classification: F02D9
IPC codes: F16K5, F02D9