The present invention provides a heat dissipation device for an engine of a motorcycle. The device includes a heat dissipation mask. The heat dissipation mask is disposed at a side of the engine such that it is not in substantial contact with the engine. The heat dissipation mask includes an open side that substantially encloses at least one side of the engine. An open is also provided at the bottom of the heat dissipation mask. The heat dissipation mask is configured to substantially correspond to a location of the leg of the rider in a riding position. Some parts of the heat dissipation mask also correspond to the engine so as to prevent the heat from spreading toward the rider. In such a way, a heat dissipation device with a reduced structure is provided, which is easy to install and is capable of dissipating heat around the engine.

A coolant bottle defines a first chamber and a second chamber fluidly coupled to the first chamber at a valve seat. The first chamber is fluidly coupled to a source of heated engine cooling fluid, while the second chamber is fluidly coupled to an engine water pump. A thermally responsive actuator is disposed within the first chamber, and has a thermally actuated sliding member having a valve seat engaging surface. The thermally actuated sliding member is movable from a first open position to a second closed position when the coolant is above a first temperature. The thermally responsive actuator is disposed within the first chamber.

A straddle vehicle is capable of discharging high-temperature outdoor air having passed through a radiator with high efficiency. A motorcycle 1 includes a radiator, a fan, and a fan shroud. The radiator lowers the temperature of a coolant by heat exchange between outdoor air and the coolant. The fan suctions outdoor air, to make the outdoor air hit the radiator arranged upstream in an outdoor air flow direction. The fan shroud covers at least part of the fan, and discharges high-temperature outdoor air, which is outdoor air suctioned by the fan and having passed through the radiator, to outside. The fan shroud has a discharge opening and an air guide. The discharge opening allows the high-temperature outdoor air to be discharged outside. The air guide guides the high-temperature outdoor air such that it is discharged through the discharge opening in a direction including a laterally outward component.

In a water-cooled inner combustion engine (1), in particular for equipping scooters and motorcycles, the arrangement of the outer cooling tubes connected to a radiator is simplified by arranging a by-pass valve (27), arranged directly on the engine block (2) at a discharge opening (18) obtained therein, which, when the cooling water is lower than a reference temperature, prevents the water circulation in the radiator (18) and it addresses it through a by-pass line (26) by implementing a cooling circuit wholly included in the engine block (2).

The motorcycle includes an engine, a radiator configured to cool cooling water for the engine, a radiator fan configured to suck and discharge air ahead of the radiator, a fan cover guiding downward the air discharged from the radiator fan, and a side cowl disposed on a side of the radiator, in which the side cowl has a cover side lower end at a lower end of a portion positioned below a portion overlapped with the fan cover in a side view, the cover side lower end being positioned adjacent to a lower end of the fan cover.

A straddle vehicle is capable of discharging high-temperature outdoor air having passed through a radiator with high efficiency. A motorcycle 1 includes a radiator, a fan, and a fan shroud. The radiator lowers the temperature of a coolant by heat exchange between outdoor air and the coolant. The fan suctions outdoor air, to make the outdoor air hit the radiator arranged upstream in an outdoor air flow direction. The fan shroud covers at least part of the fan, and discharges high-temperature outdoor air, which is outdoor air suctioned by the fan and having passed through the radiator, to outside. The fan shroud has a discharge opening and an air guide. The discharge opening allows the high-temperature outdoor air to be discharged outside. The air guide guides the high-temperature outdoor air such that it is discharged through the discharge opening in a direction including a laterally outward component.

A two-stroke engine comprises a first oiling system and a second oiling system. The first oiling system includes a low-pressure pump that distributes oil from a first oil tank to the two-stroke engine. The second oiling system includes a pump mechanically coupled to a crankshaft of the two-stroke engine, wherein the pump distributes oil from a second oil tank to an accessory at a pressure greater than the first oil pressure, wherein oil distributed to the accessory is returned to the second oil tank.

There is provided a saddle-ridden type vehicle. A cooling water flow control unit includes a first passage, a second passage, a bypass passage communicating the first and second passages and a thermostat. An engine outlet piping connects a water jacket and the first passage. A radiator inlet piping connects the first passage and a radiator. A radiator outlet piping connects the radiator and the second passage. A water pump inlet piping connects the second passage and a water pump. The water pump is disposed at a side part of a crank case and in front of a crankshaft. The cooling water flow control unit is disposed above a cylinder head cover. The radiator inlet piping, the radiator outlet piping and the water pump inlet piping are disposed between the engine and the radiator.

An installation structure for a reservoir tank includes a main frame that extends rearward from a head pipe, a down frame that extends downward from the head pipe, a bridge that connects the down frame and the main frame, a radiator disposed in front of the engine and configured to radiate heat from cooling water of an engine, and a reservoir tank configured to adjust a flow rate of cooling water in the radiator. The reservoir tank is provided above the engine and rearward of the radiator so as to overlap a region surrounded by the main frame, the down frame, and the bridge in a side view.

Examples of techniques for controlling a cooling system for an internal combustion engine using feedback linearization are provided. In one example implementation, a computer-implemented method includes receiving, by a processing device, desired temperature targets. The method further includes receiving, by the processing device, temperature feedbacks. The method further includes calculating, by the processing device, a desired temperature derivative for each of the desired temperature targets. The method further includes calculating, by the processing device, desired coolant flows from the desired temperature derivative for each of the desired temperature targets using feedback linearization. The method further includes calculating, by the processing device, actuator commands from the desired coolant flows using an inverted hydraulic model. The method further includes implementing, by the processing device, the actuator commands in actuators in the cooling system.