Patent Description:
<CIT> discloses a straddled vehicle. The straddled vehicle has a frame, a fuel tank, an engine, an exhaust pipe connected to the engine, and a canister receiving fuel vapor from the fuel tank. In this straddled vehicle, the exhaust pipe connected to the engine extends rearward along one side surface of a cylinder block of the engine. The canister is disposed in front of a crankcase of the engine on the side opposite the exhaust pipe.

In recent years, the size of the canister has been increased due to tightening of regulations on emission of the fuel vapor. For example, the larger the volume of activated carbon in the canister is, the higher the temperature of the canister is when the fuel vapor is adsorbed by the activated carbon. In case that the temperature of the canister rises, the adsorption efficiency, with which the activated carbon adsorbs the fuel vapor in the canister, decreases.

In the above-described conventional straddled vehicle, the canister is disposed in front of the crankcase and the canister is cooled by traveling wind while the straddled vehicle is running. On the other hand, there is no means for suppressing temperature rise of the canister while the straddled vehicle is stationary. Therefore, when the conventional straddled vehicle is stationary, the temperature of the canister may rise and the adsorption efficiency of the canister may decrease. <CIT> and <CIT> disclose a straddled vehicle according to the preamble of claim <NUM>.

An object of the present invention is to provide a straddled vehicle that can effectively reduce temperature rise of a canister.

A straddled vehicle according to one aspect of the present invention includes a frame, a fuel tank, a side stand, an engine, an exhaust pipe, and a canister. The fuel tank is mounted on the frame. The side stand is mounted to the frame on one side in a vehicle width direction. The engine is mounted to the frame. The engine includes a crankcase cover. The exhaust pipe is connected to the engine. The exhaust pipe is disposed on the other side in the vehicle width direction.

The canister is disposed on the one side in the vehicle width direction entirely in front of the crankcase cover in a vehicle side view. The canister receives fuel vapor from the fuel tank. The canister is disposed inside an outer surface of the crankcase cover and faces the exhaust pipe in a vehicle front view. The canister is mounted to the engine so that an upper portion of the canister and a lower portion of the canister overlap the exhaust pipe in a vehicle side view.

In the straddled vehicle according to this aspect, the canister is disposed in front of the crankcase cover and is disposed on the opposite side of the exhaust pipe in the vehicle width direction. In the vehicle front view, the canister is disposed inside an outer surface of the crankcase cover and faces the exhaust pipe. In a vehicle side view, the upper portion of the canister and the lower portion of the canister overlap the exhaust pipe.

Generally, when the straddled vehicle is stationary, air convection is generated around the exhaust pipe due to heat of the exhaust pipe. In the above straddled vehicle, the canister can be effectively cooled with the air convection, which is generated around the exhaust pipe when the straddled vehicle is stationary, by disposing the canister relative to the exhaust pipe as described above. Thereby, an adsorption efficiency of the canister can be improved. In other words, the straddled vehicle is capable of effectively reducing temperature rise of the canister.

The canister can be disposed to face the exhaust pipe when viewed from the front of the vehicle body so that the canister and the exhaust pipe do not overlap the frame when viewed from the side of the vehicle body. Thereby, the air convection can be effectively circulated because the air convection is not blocked by the frame.

The engine can include a crankcase, the crankcase cover covering an opening of the crankcase, and a cylinder block disposed on an upper portion of the crankcase. In this case, the canister is disposed in front of the cylinder block in the vehicle side view.

Thereby, the canister can be effectively cooled with not only the air convection generated by the heat of the exhaust pipe but also the air convection generated by the heat of the cylinder block. In other words, the straddled vehicle is capable of effectively reducing the temperature rise of the canister.

The engine can include a crankcase, the crankcase cover covering an opening of the crankcase, a cylinder block disposed an upper portion of the crankcase, and a cylinder head connected to an upper portion of the cylinder block. In this case, one end of the exhaust pipe is connected to the cylinder head. The canister is disposed below the one end of the exhaust pipe in the vehicle side view.

In this configuration, the cylinder block is disposed between the crankcase and the cylinder head in a vertical direction. The cylinder block is disposed between the crankcase cover and the cylinder head in the vertical direction, because the crankcase cover covers the opening of the crankcase. The cylinder block is disposed between the canister and the cylinder head in the vertical direction, because the canister is disposed in front of the crankcase cover. In other words, the canister is disposed below the cylinder block. Thereby, the canister can be cooled from an upper side thereof with the air convection generated by the heat of the cylinder block.

Also, the one end of the exhaust pipe is connected to the cylinder head. The exhaust pipe is disposed to face the canister. In other words, the exhaust pipe extends from the cylinder head toward the canister disposed below the cylinder block. Thereby, the canister can be cooled from the upper side thereof and from the side thereof with the air convection generated by the heat of the exhaust pipe. Thus, the canister can be effectively cooled with the air convection generated by the heat of the cylinder block and the heat of the exhaust pipe. In other words, the straddled vehicle is capable of effectively reducing the temperature rise of the canister.

A catalyzer can be connected to the other end of the exhaust pipe. In this case, a lower portion of the canister overlaps the exhaust pipe on the upstream side of the catalyzer in the vehicle side view.

In this configuration, the catalyzer generates heat due to a catalytic reaction and the heat of the catalyzer generates the air convection. The canister can be cooled from a lower side thereof with the air convection generated by the heat of the catalyzer, because the lower portion of the canister is positioned upstream from the catalyzer. In addition, the lower portion of the canister can be cooled with the air convection generated by the heat of the exhaust pipe, because the lower portion of the canister overlaps the exhaust pipe in the vehicle side view. Thus, the straddled vehicle is capable of effectively reducing the temperature rise of the canister with the air convection generated by the heat of the catalyzer and the heat of the exhaust pipe.

The straddled vehicle can further include a mounting structure configured to mount the canister to the crankcase. Thereby, the canister can be mounted to the crankcase or be removed from the crankcase.

The mounting structure can include a first engaging portion provided on the crankcase, a bracket including a first engaged portion with which the first engaging portion engages, and a holding member configured to hold the canister to the bracket. Thereby, the canister can be easily mounted to the crankcase or be easily removed from the crankcase.

The first engaging portion can be a male threaded portion and the first engaged portion can be a hole portion through which the male threaded portion is inserted. In this case, the bracket is mounted to the crankcase by screwing a nut onto the male threaded portion in a state where the male threaded portion is inserted through the hole. Thereby, the mounting structure can be configured with a simple structure.

The bracket can include a bracket body and a second engaged portion provided on the bracket body. In this case, the holding member is an elastic member and includes a second engaging portion which elastically engages with the second engaged portion. The canister is held by the bracket body and the holding member. Thereby, the mounting structure can be configured with a simple structure.

The canister can include a canister body, a charge port provided in an upper portion of the canister body and is configured to guide the fuel vapor from the fuel tank to the inside of the canister body, and a purge port provided in the upper portion of the canister body and is configured to guide the fuel of the canister body to the engine. Activated carbon of the canister can be effectively utilized by configuring the canister as described above, because specific gravity of the fuel vapor is generally larger than the specific gravity of air.

The canister and the engine can be mounted to the frame as an engine assembly in a state where the canister is mounted to the engine. Thereby, the canister and the engine can be easily mounted on the frame as the engine assembly.

According to the present invention, a straddled vehicle is capable of effectively reducing temperature rise of a canister.

A straddled vehicle according to an embodiment will be described below with reference to drawings. As shown in <FIG> and <FIG>, the straddled vehicle <NUM> includes a vehicle body frame <NUM>, a steering device <NUM>, a fuel tank <NUM>, an engine <NUM> (see <FIG>), a front wheel <NUM>, and a rear wheel <NUM> (See <FIG>).

The straddled vehicle <NUM> further includes a side stand <NUM>, an exhaust device <NUM>, a canister <NUM> (see <FIG>), and a mounting structure <NUM> (see <FIG>). In <FIG>, side cowls are removed to show the canister <NUM>.

In this embodiment, in a state where the rider seats on a seat <NUM>, a front direction of the rider (a left side in <FIG>), a rear direction of the rider (a right side in <FIG>), a left direction of the rider (a lower side in <FIG>), and a right direction of the rider (a upper side in <FIG>) respectively correspond to front, rear, left, and right directions of the straddled vehicle <NUM>. The left-right direction corresponds to a vehicle width direction W of the vehicle.

For example, as shown in <FIG>, when a vehicle center plane H extending in the front-rear direction is defined on the straddled vehicle <NUM>, the vehicle width direction W is defined in a direction orthogonal to the vehicle center plane H. As shown in FIG. For example, the vehicle width direction W corresponds to the left-right direction with respect to the vehicle center plane H of the vehicle.

An upper direction of the rider (an upper side in <FIG>) corresponds to an upper direction of the straddled vehicle <NUM>. A lower direction of the straddled vehicle <NUM> (a lower side in <FIG>) is a direction opposite to the upper direction of the straddled vehicle <NUM>. A vehicle side view shows a state where a side portion of the straddled vehicle <NUM> is viewed from the left direction thereof or the right direction thereof. For example, <FIG> corresponds to the vehicle side view. A vehicle front view shows a state where a front portion of the straddled vehicle <NUM> is viewed from the front direction thereof. For example, <FIG> corresponds to the vehicle front view.

As shown in <FIG> and <FIG>, the vehicle body frame <NUM> includes a head pipe <NUM> and a main frame <NUM>. The main frame <NUM> is connected to the head pipe <NUM>. The main frame <NUM> extends rearward from the head pipe <NUM>. As shown in <FIG>, the vehicle center plane H passes through the head pipe <NUM> in the front-rear direction in a vehicle upper view. The vehicle center plane H is perpendicular to the ground.

As shown in <FIG>, the steering device <NUM> includes a front fork <NUM>, a steering shaft <NUM> and a handle member <NUM>. The front fork <NUM> is rotatably supported with respect to the head pipe <NUM>. The steering shaft <NUM> is connected to the front fork <NUM>. The handle member <NUM> is connected to the steering shaft <NUM>. The fuel tank <NUM> is mounted to the vehicle body frame <NUM>. For example, the fuel tank <NUM> is mounted to an upper portion of the main frame <NUM>.

As shown in <FIG>, the engine <NUM> is mounted on the vehicle body frame <NUM>. For example, the engine <NUM> is mounted to a lower portion of the main frame <NUM>. As shown in <FIG> and <FIG>, the engine <NUM> includes a crankcase <NUM>, a crankcase cover <NUM>, a cylinder block <NUM>, and a cylinder head <NUM>.

The crankcase <NUM> is mounted to the main frame <NUM>. In a state where the crankcase <NUM> is mounted to the main frame <NUM>, the crankcase <NUM> opens outward in the vehicle width direction W. For example, the crankcase <NUM> opens in a direction away from the vehicle center plane H in the vehicle width direction W.

The crankcase cover <NUM> is disposed on one side in the vehicle width direction W. For example, the crankcase cover <NUM> is disposed on the left side of the vehicle body frame <NUM>. Specifically, the crankcase cover <NUM> is disposed on the left side of the vehicle center plane H. The crankcase cover <NUM> is mounted to the crankcase <NUM>. The crankcase cover <NUM> covers an opening of the crankcase <NUM>. The cylinder block <NUM> is disposed on an upper portion of the crankcase <NUM>. The cylinder head <NUM> is connected to an upper portion of the cylinder block <NUM>.

As shown in <FIG>, the front wheel <NUM> is rotatably supported by front forks <NUM>. The rear wheel <NUM> is rotatably supported by the vehicle body frame <NUM>, for example, the main frame <NUM>. The rear wheel <NUM> is rotated by driving force from the engine <NUM>.

As shown in <FIG>, the side stand <NUM> is mounted to the vehicle body frame <NUM>. For example, as shown in <FIG>, the side stand <NUM> is mounted to the vehicle body frame <NUM> on the one side in the vehicle width direction W. Specifically, the side stand <NUM> is mounted to the lower portion of the main frame <NUM>. The side stand <NUM> is disposed on the left side of the vehicle body frame <NUM>. For example, the side stand <NUM> is disposed on the left side of the vehicle center plane H. The side stand <NUM> swings with respect to the main frame <NUM>.

As shown in <FIG> and <FIG>, the exhaust device <NUM> includes an exhaust pipe <NUM>, a catalyzer <NUM> and a muffler <NUM>. The exhaust pipe <NUM> is mounted to the vehicle body frame <NUM>. The exhaust pipe <NUM> is mounted to the main frame <NUM>. The exhaust pipe <NUM> is connected to the engine <NUM>.

As shown in <FIG>, the exhaust pipe <NUM> is disposed on one side in the vehicle width direction W. For example, the exhaust pipe <NUM> is disposed on a right side of the vehicle body frame <NUM>. Specifically, the exhaust pipe <NUM> is disposed on the right side of the vehicle center plane H. One end of the exhaust pipe <NUM>, for example, an upper end portion 22a of the exhaust pipe <NUM> is connected to the cylinder head <NUM>. The exhaust pipe <NUM> extends downward from a front portion of the engine <NUM>, for example, from a front portion of the cylinder head <NUM>. The exhaust pipe <NUM> extends rearward along the lower portion of the main frame <NUM> (see <FIG>).

The catalyzer <NUM> is connected to the other end of the exhaust pipe <NUM>, for example, a lower end portion 22b of the exhaust pipe <NUM>. The catalyzer <NUM> is disposed between the exhaust pipe <NUM> and the muffler <NUM>. The muffler <NUM> is connected to the catalyzer <NUM>. The catalyzer <NUM> can be disposed inside one of the exhaust pipe <NUM> and the muffler <NUM> as long as the catalyzer <NUM> is disposed between the exhaust pipe <NUM> and the muffler <NUM>. In this case, the muffler <NUM> is connected to the exhaust pipe <NUM>.

The canister <NUM> shown in <FIG> receives the fuel vapor of the fuel tank <NUM>. The canister <NUM> is mounted to the engine <NUM>. The canister <NUM> is mounted to the engine <NUM> via the mounting structure <NUM> as described below. The canister <NUM> and the engine <NUM> are mounted to the vehicle body frame <NUM>, for example, the main frame <NUM> as an engine assembly in a state where the canister <NUM> mounted to the engine <NUM>.

As shown in <FIG>, the canister <NUM> is disposed in front of the crankcase cover <NUM> in a state where the canister <NUM> and the engine <NUM> mounted to the main frame <NUM>. As shown in <FIG>, the canister <NUM> is disposed on the one side in the vehicle width direction W described above. For example, the canister <NUM> is disposed on the left side of the vehicle body frame <NUM>. Specifically, the canister <NUM> is disposed on the left side of the vehicle center plane H.

As shown in <FIG>, the canister <NUM> is disposed on a side of a protruding portion 18a of the crankcase <NUM>. For example, the canister <NUM> is disposed on the left side of the protruding portion 18a of the crankcase <NUM>, that is, on the side stand <NUM> side, in the vehicle front view.

The canister <NUM> is disposed inside an outer side surface 19a of the crankcase cover <NUM> in the vehicle front view. For example, the canister <NUM> is disposed between the vehicle center plane H and the outer side surface 19a of the crankcase cover <NUM>. Specifically, the canister <NUM> is disposed between the vehicle center plane H and a plane P. The plane P is parallel to the vehicle center plane H and is in contact with an outermost surface of the crankcase cover <NUM>.

As shown in <FIG>, the canister <NUM> is disposed so that an upper portion 10a of the canister <NUM> and a lower portion 10b of the canister <NUM> overlap the exhaust pipe <NUM> in the vehicle side view, in a state where the canister <NUM> and the engine <NUM> are mounted to the main frame <NUM>.

The canister <NUM> is disposed to face the exhaust pipe <NUM> in the vehicle front view so that the canister <NUM> and the exhaust pipe <NUM> do not overlap the main frame <NUM> in the vehicle side view. In other words, the canister <NUM> is disposed to face the exhaust pipe <NUM> in the vehicle front view in a state where the main frame <NUM> is not disposed between the canister <NUM> and the exhaust pipe <NUM>.

As shown in <FIG>, the canister <NUM> is disposed in front of the cylinder block <NUM> in the vehicle side view. For example, the canister <NUM> is disposed in front of a straight line L, which is defined by a front surface of the cylinder block <NUM>, in the vehicle side view. The straight line L contacts the front surface of the cylinder block <NUM> at least two points.

As shown in <FIG>, the canister <NUM> is disposed below one end of the exhaust pipe <NUM> , for example, the upper end portion 22a of the exhaust pipe <NUM> in the vehicle side view. The canister <NUM> is disposed above the catalyzer <NUM>.

As shown in <FIG> and <FIG>, the lower portion 10b of the canister <NUM> is disposed above the catalyzer <NUM>. As shown in <FIG>, the lower portion 10b of the canister <NUM> overlaps the exhaust pipe <NUM> on a side of the lower end portion 22b of the exhaust pipe <NUM> in the vehicle side view. The lower portion 10b of the canister <NUM> overlaps the exhaust pipe <NUM> on an upstream side of the catalyzer <NUM> in the exhaust device <NUM>.

As shown in <FIG>, the canister <NUM> includes a canister body <NUM>, a charge port <NUM>, and a purge port <NUM>. Activated carbon is disposed in the canister body <NUM>. For example, an outer shape of the canister body <NUM> is formed in a rectangular parallelepiped shape. The canister body <NUM> is disposed such that the longest side of the canister body <NUM> is aligned with the straight line L (see <FIG>). In other words, the canister body <NUM> is used in a vertically placed state.

As shown in <FIG>, the charge port <NUM> is provided on the upper portion of the canister body <NUM>. The charge port <NUM> guides the fuel vapor from the fuel tank <NUM> into the canister body <NUM>. The purge port <NUM> is provided in the upper portion of the canister body <NUM>. The purge port <NUM> guides fuel of the canister body <NUM> to the engine <NUM>.

As shown in <FIG>, the mounting structure <NUM> is used to mount the canister <NUM> to the crankcase <NUM>. The mounting structure <NUM> includes a male threaded portion <NUM> (an example of a first engaging portion), a bracket <NUM>, and a holding member <NUM>. The male threaded portion <NUM> is provided on the crankcase <NUM>.

As shown in <FIG>, the bracket <NUM> includes a bracket body <NUM>, a hole portion <NUM> (an example of a first engaged portion), and a plurality of engaged protrusions <NUM> (an example of a second engaged portion). The bracket body <NUM> is mounted to the crankcase <NUM>.

As shown in <FIG>, the bracket body <NUM> includes a first bracket 31a and a second bracket 31b. The first bracket 31a is mounted to the crankcase <NUM>. The second bracket 31b is mounted to the first bracket 31a.

As shown in <FIG>, the hole portion <NUM> penetrates the bracket body <NUM>. For example, a plurality of hole portions <NUM> penetrate the first bracket 31a. A plurality of male threaded portions <NUM> are respectively inserted into the plurality of hole portions <NUM>. In this state, the first bracket 31a is mounted to the crankcase <NUM> by respectively screwing a plurality of nuts <NUM> onto the plurality of male threaded portions <NUM>. The plurality of engaged protrusions <NUM> are provided on the first bracket 31a. The plurality of engaged protrusions <NUM> lock the holding member <NUM>.

The holding member <NUM> is used to hold the canister <NUM> to the bracket <NUM>. For example, as shown in <FIG>, the holding member <NUM> is an elastic member. The holding member <NUM> covers the canister body <NUM>. The holding member <NUM> is elastically engaged with the plurality of engaged protrusions <NUM>.

As shown in <FIG>, the holding member <NUM> includes an engaging hole <NUM> (an example of a second engaging portion). For example, the plurality of engaging holes <NUM> are respectively engaged with the plurality of engaged protrusions <NUM>. The plurality of engaging holes <NUM> are respectively fitted into the plurality of engaged protrusions <NUM> in a state where the holding member <NUM> covers the canister body <NUM>. Thereby, the canister body <NUM> is held by the first bracket 31a and the holding member <NUM>.

In this state, the second bracket 31b is mounted to the first bracket 31a from outside of the holding member <NUM>. Thereby, the canister body <NUM> and the holding member <NUM> are sandwiched between the first bracket 31a and the second bracket 31b.

In the straddled vehicle <NUM> configured as described above, the canister <NUM> is disposed in front of the crankcase cover <NUM> and is disposed on the opposite side of the exhaust pipe <NUM> in the vehicle width direction W. The canister <NUM> is disposed inside the outer surface of the crankcase cover <NUM> and faces the exhaust pipe <NUM> in the vehicle front view. The upper portion of the canister <NUM> and the lower portion of the canister <NUM> overlap the exhaust pipe <NUM> in the vehicle side view. With this configuration, the adsorption efficiency of the canister <NUM> can be improved. In other words, the temperature rise of the canister <NUM> can be effectively reduced in the straddled vehicle <NUM>.

Claim 1:
A straddled vehicle (<NUM>) comprising:
a frame (<NUM>);
a fuel tank (<NUM>) mounted on the frame (<NUM>);
a side stand (<NUM>) mounted to the frame (<NUM>) on one side in a vehicle width direction;
an engine (<NUM>) mounted to the frame (<NUM>) and including a crankcase cover (<NUM>); and
an exhaust pipe (<NUM>) connected to the engine and disposed on the other side in the vehicle width direction;
a canister (<NUM>) receiving fuel vapor from the fuel tank (<NUM>); the canister (<NUM>) is disposed inside an outer surface of the crankcase cover (<NUM>) and faces the exhaust pipe (<NUM>) in a vehicle front view; and
the canister (<NUM>) is mounted to the engine (<NUM>) so that an upper portion of the canister (<NUM>) and a lower portion of the canister (<NUM>) overlap the exhaust pipe (<NUM>) in a vehicle side view, characterized in that the canister (<NUM>) is entirely disposed on the one side in the vehicle width direction in front of the crankcase cover (<NUM>) in a vehicle side view.