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EP-4545760-B1 - ENGINE

EP4545760B1EP 4545760 B1EP4545760 B1EP 4545760B1EP-4545760-B1

Inventors

  • YAMADA, SHINICHI
  • RYU, Yuki
  • KOUSAKA, Shogo

Dates

Publication Date
20260513
Application Date
20240910

Claims (7)

  1. A straddle-type vehicle (1) comprising an engine (40) for the straddle-type vehicle (1), the engine (40) mounted on a vehicle frame (10) in which a down frame (14) extends downward from a head pipe (11), the engine (40) comprising: a cylinder head (43) having an exhaust port (47) formed thereon; an exhaust pipe (70) connected to the exhaust port (47) of the cylinder head (43); and an exhaust gas sensor (84) attached to the exhaust pipe (70), wherein the exhaust pipe (70) extends downward passing through a first lateral side of the down frame (14), crosses a front side of the down frame (14), and extends upward passing through a second lateral side of the down frame (14), a part of the exhaust pipe (70) that crosses the down frame (14) is a straight portion (73), the exhaust gas sensor (84) is attached to the straight portion (73) and overlaps the down frame (14) from the front side, characterised in that in a side view, the exhaust gas sensor (84) overlaps the exhaust pipe (70) passes through both lateral sides of the down frame (14).
  2. The straddle-type vehicle (1) according to claim 1, wherein in a front view, the exhaust gas sensor (84) extends in an upper-lower direction so as to be parallel to the down frame (14), and the exhaust gas sensor (84) is positioned inside both side surfaces of the down frame (14) in an engine width direction.
  3. The straddle-type vehicle (1) according to claim 1 or claim 2, wherein in a side view, an axis of the exhaust gas sensor (84) is inclined upward so as to be close to an axis of the down frame (14).
  4. The straddle-type vehicle (1) according to any preceding claim, wherein in a side view, the exhaust gas sensor (84) is positioned inside both ends of the straight portion (73) in a front-rear direction.
  5. The straddle-type vehicle (1) according to any preceding claim, wherein a catalyst (81) is accommodated in the exhaust pipe (70), on the second lateral side of the down frame (14), and in a side view, the catalyst (81) overlaps the exhaust gas sensor (84).
  6. The straddle-type vehicle (1) according to any preceding claim, wherein a guard member (83) protrudes from the straight portion (73), and the guard member (83) covers the exhaust gas sensor (84) from a front side.
  7. The straddle-type vehicle (1) according to claim 6, wherein in a side view, the guard member (83) protrudes vertically from the straight portion (73), and the exhaust gas sensor (84) is inclined upward so as to be away from the guard member (83).

Description

TECHNICAL FIELD The present disclosure relates to a straddle-type vehicle having an engine. BACKGROUND ART An engine for a straddle-type vehicle has an exhaust pipe that is curved in a U-shape in front of a down tube (see, for example, JP3489242B). In the engine described in JP3489242B, a cylinder is disposed on a crank case, and a cylinder head is disposed on the cylinder. An exhaust port is formed in a front surface of the cylinder head, and an exhaust pipe extends downward from the exhaust port toward the crank case. In front of the crank case, the exhaust pipe is curved upward in a U-shape and extends to the cylinder, and the exhaust pipe passes through a lateral side of the cylinder and extends to a rear side of the vehicle and then connected to a muffler. Incidentally, an exhaust gas sensor is attached to the exhaust pipe, but if the exhaust pipe has many bends, the flow of exhaust gas is deviated, thereby deteriorating detection accuracy of the exhaust gas sensor. Depending on where the exhaust gas sensor is disposed, there is a high risk of damage to the exhaust gas sensor or a lead wire. Other straddle-type vehicles comprising exhaust gas sensors are known from JP7338145B2 and US2010/032226A1. SUMMARY OF INVENTION Aspect of non-limiting embodiments of the present disclosure relates to provide an engine capable of reducing the risk of damage to the exhaust gas sensor in a model in which the exhaust pipe passes through the lateral side of the cylinder. Aspects of certain non-limiting embodiments of the present disclosure address the features discussed above and/or other features not described above. However, aspects of the non-limiting embodiments are not required to address the above features, and aspects of the non-limiting embodiments of the present disclosure may not address features described above. According to an aspect of the present disclosure, there is provided a straddle-type vehicle comprising an engine for the straddle-type vehicle, the engine mounted on a vehicle frame in which a down frame extends downward from a head pipe, the engine including: a cylinder head having an exhaust port formed thereon;an exhaust pipe connected to the exhaust port of the cylinder head; andan exhaust gas sensor attached to the exhaust pipe,in which the exhaust pipe extends downward passing through a first lateral side of the down frame, crosses a front side of the down frame, and extends upward passing through a second lateral side of the down frame,a part of the exhaust pipe that crosses the down frame is a straight portion,the exhaust gas sensor is attached to the straight portion and overlaps the down frame from the front side, andin a side view, the exhaust gas sensor overlaps the exhaust pipe passing through both lateral sides of the down frame. BRIEF DESCRIPTION OF DRAWINGS Exemplary embodiment(s) of the present invention will be described in detail based on the following figures, wherein: FIG. 1 is a right side view of a straddle-type vehicle according to an embodiment;FIG. 2 is a right side view of a periphery of an engine according to the present embodiment;FIG. 3 is a front view of the periphery of the engine according to the present embodiment;FIG. 4 is a perspective view of the periphery of the engine according to the present embodiment when obliquely viewed from a rear and right side;FIG. 5 is a cross-sectional view of the engine in FIG. 3 taken along a line V-V; andFIG. 6 is a cross-sectional view of the engine in FIG. 3 taken along a line VI-VI. DESCRIPTION OF EMBODIMENTS An engine according to one aspect of the present disclosure is mounted on a vehicle frame of a straddle-type vehicle. An exhaust port is formed in a cylinder head of the engine, and an exhaust pipe is connected to the exhaust port of the cylinder head, and an exhaust gas sensor is attached to the exhaust pipe. A down frame extends downward from a head pipe of the vehicle frame, and the exhaust pipe extends downward through one lateral side of the down frame. After crossing a front side of the down frame, the exhaust pipe passes through the other lateral side of the down frame and extends upward. A part of the exhaust pipe that crosses the down frame is a straight portion, and the exhaust gas sensor is attached to the straight portion and overlaps the down frame from the front side. The exhaust gas sensor is attached to the straight portion where the flow of exhaust gas is less deviated, and the exhaust gas sensor overlaps the down frame from the front side and is approximately perpendicular to the straight portion. The detection accuracy is improved by directing the detection end of the exhaust gas sensor approximately perpendicular to the flow of the exhaust gas. The straight portion of the exhaust pipe vibrates less than a bent portion, allowing the exhaust gas sensor to be stably supported, and the exhaust gas sensor is positioned on the inside in the vehicle width direction, thereby reducing the risk of damage to the exh