The present invention concerns a multi-cylinder engine comprising a throttle body (5) in which a throttle intake-air passage (6) is provided. A throttle valve (7) is arranged in this throttle intake-air passage (6). Attached to the throttle body (5) is an injector (8), a leading end portion (9) of w
The present invention concerns a multi-cylinder engine comprising a throttle body (5) in which a throttle intake-air passage (6) is provided. A throttle valve (7) is arranged in this throttle intake-air passage (6). Attached to the throttle body (5) is an injector (8), a leading end portion (9) of which is arranged opposite to an interior area of the throttle intake-air passage (6) downstream of the throttle valve (7) and is opened to provided a liquid-fuel injection hole (10). An intake-air pressure sensor (15) is attached to the throttle body (5) together with the injector (8) and an intake-air pressure introduction passage (18) has an inlet (18a) provided by opening an inner peripheral surface of the throttle intake-air passage (6) upstream of the injector (8).
대표청구항▼
What is claimed is: 1. A multi-cylinder engine comprising a cylinder head (1) to which an intake-air distribution passage (2) is attached, the intake-air distribution passage (2) distributing a fuel-air mixture to a plurality of cylinders (3) and having a single distribution passage inlet (4) to wh
What is claimed is: 1. A multi-cylinder engine comprising a cylinder head (1) to which an intake-air distribution passage (2) is attached, the intake-air distribution passage (2) distributing a fuel-air mixture to a plurality of cylinders (3) and having a single distribution passage inlet (4) to which a throttle body (5) is attached, liquid fuel being supplied to the throttle body (5), wherein the throttle body (5) has an interior area provided with a throttle intake-air passage (6), within which a throttle valve (7) is arranged, an injector (8) being attached to the throttle body (5) and having a leading end portion (9) which is positioned opposite to an interior area of the throttle intake-air passage (6) downstream of the throttle valve (7) and is opened to provide a liquid-fuel injection hole (10), an intake-air pressure sensor (15) that detects an intake-air pressure of the throttle intake-air passage (6) and an engine's rotation-number sensor (16) that detects the number of engine's rotations being associated with the injector (8) through a control means (17), the control means (17) controlling an amount of the liquid fuel to be injected from the injector (8), based on the intake-air pressure and the number of engine's rotations, the intake-air pressure sensor (15) being attached to the throttle body (5) together with the injector (8), the throttle intake-air passage (6) of the throttle body (5) having a peripheral wall in which there is provided an intake-air pressure introduction passage (18) for introducing the intake-air pressure within the throttle intake-air passage (6) to the intake-air pressure sensor (15), an inner peripheral surface of the throttle intake-air passage (6) being opened to provide an inlet (18a) of the intake-air pressure introduction passage (18) upstream of the injector (8). 2. The multi-cylinder engine as set forth in claim 1, wherein when it is imagined that a transverse line (19) radially crosses the throttle intake-air passage (6) of a circular cross section and moves toward the inlet (18a) of the intake-air pressure introduction passage (18) and that a transverse extending line (19a) is extended from this transverse line (19) to an exterior area of the throttle intake-air passage (6) via the inlet (18a) of the intake-air pressure introduction passage (18), the intake-air pressure introduction passage (18), which is formed by drilling, is oriented so that it makes an angle of at least 45 degrees and not more than 75 degrees with respect to the imaginary transverse extending line (19a). 3. The multi-cylinder engine as set forth in claim 2, wherein on the projected drawing whose surface is perpendicular to a center axis (6a) of the throttle intake-air passage (6), the intake-air pressure introduction passage (18) is oriented so that it makes an angle (18α) of at least 45 degrees and not more than 75 degrees with respect to the imaginary transverse extending line (19a). 4. The multi-cylinder engine as set forth in claim 2, wherein a butterfly valve is used for the throttle valve (7), and on the projected drawing whose surface is in parallel to the center axis (6a) of the throttle intake-air passage (6) and the axis (12) of the throttle valve (7), this intake-air pressure introduction passage (18) has its inlet (18a) arranged so that the inlet (18a) overlaps the center axis (6a) of the throttle intake-air passage (6), the intake-air pressure introduction passage (18) being inclined downwardly from its outlet (18b) to its inlet (18a), when imaging that an extending axis (6c) is extended from the center axis (6a) of the throttle intake-air passage (6) to an exterior area of the throttle intake-air passage (6) through an inlet (6b) of the throttle intake-air passage (6), on the projected drawing whose surface is in parallel to the center axis (6a) and the axis (12) of the throttle valve (7), the intake-air pressure introduction passage (18) being oriented so that it makes an angle (18) of at least 45 degrees and not more than 75 degrees. 5. The multi-cylinder engine as set forth in claim 1, wherein the throttle body (5) is opened to provide a hole (20) for attaching the intake-air pressure sensor (15), the attaching hole (10) being communicated with the intake-air pressure introduction passage (18), and the attaching hole (20) is formed to face downwardly, the intake-air pressure sensor (15) being attached to the attaching hole (20), and is provided with a liquid fuel reservoir (21) therebelow, the liquid fuel reservoir (21) having an upper portion opened to provide the outlet (18b) of the intake-air pressure introduction passage (18). 6. The multi-cylinder engine as set forth in claim 1, wherein a direction of the center axis (6a) of the throttle intake-air passage (6) is taken as a front and rear direction and a downstream side of the axis (12) of the throttle valve (7) is deemed as the 'rear', and when seen in a direction parallel to the axis (12) of the throttle valve (7), a direction perpendicular to the front and rear direction is taken as a left and right lateral direction, the injector (8) being arranged behind the throttle input arm (22) and the attaching hole (20) for the intake-air pressure sensor (15) having a boss (20a) arranged laterally of the throttle input arm (22). 7. The multi-cylinder engine as set forth in claim 6, wherein the attaching hole (20) for the intake-air pressure sensor (15) makes its boss (20a) serve as a stopper for the pivotal movement of the throttle input arm (22). 8. The multi-cylinder engine as set forth in claim 1, wherein the throttle valve (7) of butterfly-type is disposed within the throttle intake-air passage (6) and is interlockingly connected to a mechanical governor (42), and an intake-air amount is adjusted based on a degree of opening of the throttle valve (7), and in order for the control means (17) to supply fuel of an amount in proportion to the intake-air amount to be metered, based on the intake-air pressure of the throttle intake-air passage (6) and the number of engine's rotations, from a fuel supply means (11) to the intake air, an inner peripheral surface of the throttle intake-air passage (6) has an annular inner peripheral surface of a predetermined width around the throttle valve (7) taken as a valve-surrounding inner peripheral surface (6d) and an annular inner peripheral surface adjacent this valve-surrounding inner peripheral surface (6d) is deemed as an adjacent inner peripheral surface (6e), the most distant portion from the axis (12) of the throttle valve (7) being taken as a pivotal end portion (7a), the adjacent inner peripheral surface (6e) being formed so that a passage defined by the surface (6e) has a sectional area progressively increasing as it goes further and further away from an end edge portion (6f) of the valve-surrounding inner peripheral surface (6d), when the engine is in operation at a low speed with a light load, the pivotal end portion (7a) of the throttle valve (7) existing at a slightly-open position (7c), which is close to a full-closed position (7b), being made to pivot within the adjacent inner peripheral surface (6e). 9. The multi-cylinder engine as set forth in claim 8, wherein the adjacent inner peripheral surface (6e) is tapered as a truncated cone so that the sectional area of its passage is progressively increasing from the upstream end edge (6f) of the valve-surrounding inner peripheral surface (6d) toward an upstream side. 10. The multi-cylinder engine as set forth in claim 1, wherein the annular peripheral surface of the predetermined width of the throttle intake-air passage (6) is formed as a venturi portion (6i), which is opened to provide the inlet (18a) of the intake-air pressure introduction passage (18). 11. The multi-cylinder engine as set forth in claim 1, wherein a radial direction of the throttle intake-air passage (6) perpendicular to the axis (12) of the throttle valve (7) is taken as a left and right lateral direction, in order to arrange the inlet (18a) of the intake-air pressure introduction passage (18) in a lateral inner peripheral surface of the throttle intake-air passage (6), when the throttle valve (7) is partitioned in the left and right direction with the valve axis (12) as a boundary at a full-closed position (7b) to form left and right lateral half portions, one of which is directed toward the downstream side of the valve axis (12) of the throttle valve (7) when the throttle valve (7) is open, to be deemed as a downstream-oriented half portion (7e), while the throttle valve (7) is opening, the downstream-oriented half portion (7e) moves toward a lateral inner peripheral surface of the throttle intake-air passage (6), another lateral inner peripheral surface (6j) being opposite to this lateral inner peripheral surface, the intake-air pressure introduction passage (18) having its inlet (18a) arranged in that another lateral inner peripheral surface (6j). 12. The multi-cylinder engine as set forth in claim 1, wherein the breather outlet (51) is arranged opposite to an interior area of a region extending from the throttle intake-air passage (6) to the distribution passage inlet portion (4) of the intake-air distribution passage (2). 13. The multi-cylinder engine as set forth in claim 12, wherein a direction of the center axis (6a) of the throttle intake-air passage (6) is taken as a front and rear direction and an downstream side of the axis (12) of the throttle valve (7) is deemed as the 'rear', and when seen in a direction parallel to the axis (12) of the throttle valve (7), the breather outlet (51) is arranged just behind the valve axis (12). 14. The multi-cylinder engine as set forth in claim 1, wherein every cylinder (3) is provided with an ignition plug (36), an ignition circuit (37) of which is associated with a crank-shaft phase sensor (38) through the control means (17) and when the control means (17) performs an ignition timing control for throwing sparks from the ignition plug (36) at every predetermined timing of a combustion cycle of every cylinder (3), the ignition timing is made earlier for the cylinder (3) of a lower compression ratio. 15. The multi-cylinder engine as set forth in claim 14, wherein the control means (17) performs the ignition timing control based on a mutually different ignition timing control map for every cylinder (3). 16. The multi-cylinder engine as set forth in claim 1, wherein the fuel supply means (11) is arranged opposite to an interior area of a region extending from the throttle intake-air passage (6) to the distribution passage inlet portion (4) of the intake-air distribution passage (2) and is associated with a crank-shaft phase sensor (38) through the control means (17), and when the control means (17) performs the fuel supply control for supplying the fuel to be fed to every cylinder (3), from the fuel supply means (11) to the intake air in the region at every predetermined timing of a combustion cycle for every cylinder (3), based on the detected phase of the crank shaft (39), in the case of the same fuel supply amount, more fuel is supplied to the cylinder (3) where the fuel-air mixture has a lower fuel concentration. 17. The multi-cylinder engine as set forth in claim 16, wherein the control means (17) performs the fuel supply control based on a mutually different fuel supply control map for every cylinder (3). 18. The multi-cylinder engine as set forth in claim 1, wherein the fuel supply means (11) is arranged opposite to an interior area of a region extending from the throttle intake-air passage (6) to the distribution passage inlet portion (4) of the intake-air distribution passage (2) and is associated with a crank-shaft phase sensor (38) through the control means (17), and when the control means (17) performs the fuel supply control for supplying the fuel to be fed to every cylinder (3), from a fuel supply means (11) to the intake air in the region at every predetermined timing of a combustion cycle for every cylinder (3), based on the detected phase of the crank shaft (39), in the case of the same fuel supply start-timing, the fuel supply starts earlier for the cylinder (3) where the fuel-air mixture has a lower fuel concentration. 19. The multi-cylinder engine as set forth in claim 18, wherein the control means (17) performs the fuel supply control based on a mutually different fuel supply control map for each of the cylinders (3). 20. The multi-cylinder engine as set forth in claim 1, wherein the cylinder head (1) has a side surface to which a longitudinal box-shaped intake-air passage wall (2a) extending along a direction of arranging the plurality of cylinders (3) is attached, and a straight continuous intake-air distribution passage (2) is formed in the longitudinal direction within the box-shaped intake-air passage wall (2a), the respective cylinders (3) having their intake-air port inlets (3a) disposed opposite to an interior area of the intake-air distribution passage (2) while retaining a predetermined spacing in the longitudinal direction. 21. The multi-cylinder engine as set forth in claim 1, wherein the throttle valve (7) has an upstream side opened to provide an upstream breather outlet (52), and when communicating the upstream breather outlet (52) with a breather chamber (56) through an upstream breather passage (52a), the throttle valve (7) has a downstream side opened to provide a downstream breather outlet (53), which is communicated with the breather chamber (56) through an upstream breather passage (53a). 22. The multi-cylinder engine as set forth in claim 21, wherein a common breather passage (54) is conducted out of the breather chamber (56), and the upstream breather passage (52a) and the downstream breather passage (53a) are branched from the common breather passage (54). 23. The multi-cylinder engine as set forth in claim 22, wherein the upstream breather passage (52a) projecting from the common breather passage (54) has a starting end portion (52b) oriented upwards. 24. The multi-cylinder engine as set forth in claim 22, wherein the downstream breather passage (53a) is oriented downwardly from the common breather passage (54) toward the downstream breather outlet (53). 25. The multi-cylinder engine as set forth in claim 21, wherein the downstream breather passage (53a) is smaller than the upstream breather passage (52a) in sectional area. 26. The multi-cylinder engine as set forth in claim 21, wherein the cylinder head (1) has an upper portion to which the head cover (25) is attached and this head cover (25) covers a rocker arm (55), when the breather chamber (56) is arranged at a ceiling portion of this head cover (25), the breather chamber (56) having its inlet (56a) arranged at a positioned deviated from just above the rocker arm (55) and lower than a bottom wall (56b) of the breather chamber (56).
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이 특허에 인용된 특허 (5)
Russell J. Wakeman, Integral engine control sensor.
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