Abstract: A jet-propelled boat includes a power unit that applies a propulsive force to a ship body by injecting water taken in from a water inlet while pressurizing the water, a position detection unit that detects a position of the ship body, a determination unit that determines whether or not an operation mode is a fixed position mode, and a power control unit that controls the power unit based on detection information by the position detection unit so that a position of the ship body falls within a target range including a specific anchor position in a case where the determination unit determines that the operation mode is the fixed position mode.

Abstract: A driving control system includes a controller which is configured to, in response to a command for starting an auto-cruise mode generated by the operation of an input device, control an engine speed or a vehicle speed so that a value detected by a speed detector falls within a cruising speed range, when the value detected by the speed detector is outside the cruising speed range; and to then cause the watercraft to cruise at a constant engine speed or at a constant vehicle speed.

Abstract: A slip detection system for a vehicle comprises an engine speed detector configured to detect an engine speed of an engine mounted in the vehicle, an engine speed increase rate detector configured to detect an increase rate in a predetermined time of the engine speed detected by the engine speed detector, and a slip determiner configured to integrate values of increase rates in respective predetermined times, from when the increase rate detected by the engine speed increase rate detector becomes larger than a first threshold until the increase rate becomes smaller than the first threshold, and to determine that a drive wheel of the vehicle is in a slip-state when an integrated value resulting from integration of the values of the increase rates becomes larger than a second threshold.

Abstract: A method of controlling an engine for a vehicle including increasing an amount of air taken into the engine to an amount larger than an idling air amount corresponding an idling engine speed, when an engine speed of the engine is predetermined value or more, a throttle valve for controlling the amount of air taken into the engine has not been operated to be opened, and a clutch is in an off-state not to permit transmission of a drive force from the engine to a running drive element of the vehicle.

Abstract: A jet-propulsion personal watercraft includes an engine configured to generate a driving power for generating a propulsion force to propel the watercraft, an engine speed changing system configured to be able to change an engine speed of the engine, a determiner configured to determine whether or not to execute control for effectively steering the watercraft at start of deceleration, and an engine controller configured to control the engine speed changing system based on information received from the determiner. The engine controller is configured to, when the determiner determines that the control for effectively steering the watercraft should not be executed, control the engine speed changing system so that a decrease rate of the engine speed immediately after the determination is smaller than a decrease rate of the engine speed in a case where the determiner determines that the control for effectively steering the watercraft should not be executed.

Abstract: A driving control system includes a controller which is configured to, in response to a command for starting an auto-cruise mode generated by the operation of an input device, control an engine speed or a vehicle speed so that a value detected by a speed detector falls within a cruising speed range, when the value detected by the speed detector is outside the cruising speed range; and to then cause the watercraft to cruise at a constant engine speed or at a constant vehicle speed.

Abstract: A leisure vehicle including a plurality of communication devices built into a vehicle body of the leisure vehicle; and a multiplex communication line through which the plurality of communication devices are coupled to each other. The communication devices are configured to perform multiplexed data communication through the multiplex communication line. The multiplex communication line is positioned a distance apart from a noise source mounted in the vehicle body so as not to be subjected to a noise.

Abstract: A theft prevention apparatus of a leisure vehicle equipped with a rider's seat which opens outside is disclosed.

Abstract: An electronic key system for a leisure vehicle is provided. The electronic key system may include a portable device configured to transmit a user identification code, and an electronic key controller that is configured to receive the user identification code and to cause an electric power supply of the leisure vehicle to be turned on upon receiving the user identification code. The electric key controller may be configured to transmit a confirmation signal when acceleration of the leisure vehicle is higher than a predetermined acceleration value, and the portable device may be configured to, upon receiving the confirmation signal, transition from a sleep mode to an active mode to transmit a response signal to the electronic key controller. The electronic key controller may be configured to output a control signal to cause an alarm to be raised when no response signal is received.

Abstract: A slip detection system for a vehicle comprises an engine speed detector configured to detect an engine speed of an engine mounted in the vehicle, an engine speed increase rate detector configured to detect an increase rate in a predetermined time of the engine speed detected by the engine speed detector, and a slip determiner configured to integrate values of increase rates in respective predetermined times, from when the increase rate detected by the engine speed increase rate detector becomes larger than a first threshold until the increase rate becomes smaller than the first threshold, and to determine that a drive wheel of the vehicle is in a slip-state when an integrated value resulting from integration of the values of the increase rates becomes larger than a second threshold.

Abstract: A jet-propulsion personal watercraft includes an engine configured to generate a driving power for generating a propulsion force to propel the watercraft, an engine speed changing system configured to be able to change an engine speed of the engine, a determiner configured to determine whether or not to execute control for effectively steering the watercraft at start of deceleration, and an engine controller configured to control the engine speed changing system based on information received from the determiner. The engine controller is configured to, when the determiner determines that the control for effectively steering the watercraft should not be executed, control the engine speed changing system so that a decrease rate of the engine speed immediately after the determination is smaller than a decrease rate of the engine speed in a case where the determiner determines that the control for effectively steering the watercraft should not be executed.

Abstract: A method of feeding fuel to an engine, comprising the steps of determining whether or not the engine is decelerating based on a time-lapse change rate of an engine speed of the engine, and reducing an amount of the fuel to be fed to air taken into the engine from outside to less than a reference amount preset according to the engine speed when it is determined that the engine is decelerating.

Abstract: An electronic key system for a leisure vehicle is provided. The electronic key system may include a portable device configured to transmit a user identification code, and an electronic key controller that is configured to receive the user identification code and to cause an electric power supply of the leisure vehicle to be turned on upon receiving the user identification code. The electric key controller may be configured to transmit a confirmation signal when acceleration of the leisure vehicle is higher than a predetermined acceleration value, and the portable device may be configured to, upon receiving the confirmation signal, transition from a sleep mode to an active mode to transmit a response signal to the electronic key controller. The electronic key controller may be configured to output a control signal to cause an alarm to be raised when no response signal is received.

Abstract: A four-cycle engine typically including a crankshaft provided with a first gear, a camshaft provided with a second gear, an endless rotation transmission that is installed around the first and second gears and is configured to transmit rotation of the crankshaft to the camshaft, a crank phase detecting device configured to detect a rotational phase of the crankshaft that is obtained by dividing a phase corresponding to one rotation of the crankshaft by a number that is equal to or more than a half of teeth of the second gear of the camshaft, and a cam phase detecting device configured to detect at least one rotational phase of the camshaft.

Abstract: A leisure vehicle including a plurality of communication devices built into a vehicle body of the leisure vehicle; and a multiplex communication line through which the plurality of communication devices are coupled to each other. The communication devices are configured to perform multiplexed data communication through the multiplex communication line. The multiplex communication line is positioned a distance apart from a noise source mounted in the vehicle body so as not to be subjected to a noise.

Abstract: A method of feeding fuel to an engine, comprising the steps of determining whether or not the engine is decelerating based on a time-lapse change rate of an engine speed of the engine, and reducing an amount of the fuel to be fed to air taken into the engine from outside to less than a reference amount preset according to the engine speed when it is determined that the engine is decelerating.

Abstract: A method of controlling an engine for a vehicle including increasing an amount of air taken into the engine to an amount larger than an idling air amount corresponding an idling engine speed, when an engine speed of the engine is predetermined value or more, a throttle valve for controlling the amount of air taken into the engine has not been operated to be opened, and a clutch is in an off-state not to permit transmission of a drive force from the engine to a running drive element of the vehicle.

Abstract: A main switch apparatus of a small watercraft is provided. The main switch apparatus of a small watercraft having a main switch. The main switch apparatus includes a plurality of keys, each for operating the main switch, each assigned a different user ID information. The main switch apparatus may further include an ID information detector for detecting the user ID information assigned to one of the plurality of keys applied to the main switch, a controller for controlling the small watercraft, configured to be activated by each one of the plurality of keys, and a control pattern memory for storing a plurality of control patterns of the controller corresponding to the respective user ID information. The controller is typically configured to read out the control pattern stored in the control pattern memory corresponding to the user ID information detected by the user ID information detector and to execute a control of the watercraft based on the read out control pattern.

Abstract: A four-cycle engine typically including a crankshaft provided with a first gear, a camshaft provided with a second gear, an endless rotation transmission that is installed around the first and second gears and is configured to transmit rotation of the crankshaft to the camshaft, a crank phase detecting device configured to detect a rotational phase of the crankshaft that is obtained by dividing a phase corresponding to one rotation of the crankshaft by a number that is equal to or more than a half of teeth of the second gear of the camshaft, and a cam phase detecting device configured to detect at least one rotational phase of the camshaft.

Abstract: A theft prevention apparatus of a leisure vehicle equipped with a rider's seat which opens outside is disclosed.