초록 ▼

A jet drive cavitation control system briefly limits engine output power to prevent the onset of impeller cavitation when pressure upstream of the impeller indicates the likelihood of imminent impeller cavitation. The system uses a pressure sensor to sense water pressure, preferably immediately upst

A jet drive cavitation control system briefly limits engine output power to prevent the onset of impeller cavitation when pressure upstream of the impeller indicates the likelihood of imminent impeller cavitation. The system uses a pressure sensor to sense water pressure, preferably immediately upstream of the impeller. The pressure sensor generates a signal that is transmitted to an electronic controller which controls the operation of the internal combustion engine that powers the jet drive. A threshold cavitation water pressure value is preselected at a point before the onset of impeller cavitation is likely. When the measured water pressure drops to or below the threshold cavitation water pressure value, the electronic controller immediately limits engine output to prevent impeller cavitation. Engine power output can be limited in any number of ways, for example, clipping spark plug ignition, retarding spark plug ignition, limiting throttle, limiting the amount of air supplied to the engine, limiting the amount of fuel supplied to the engine, adding water to the exhaust stream or modifying the configuration or operation of exhaust port valves, etc.

대표청구항 ▼

[ I claim:] [1.] A jet propelled watercraft comprising:an engine;a watercraft jet drive including a duct and an impeller located within the duct;a water inlet on the underside of the watercraft that provides an opening for water to flow through the duct to the impeller, wherein the impeller is drive

[ I claim:] [1.] A jet propelled watercraft comprising:an engine;a watercraft jet drive including a duct and an impeller located within the duct;a water inlet on the underside of the watercraft that provides an opening for water to flow through the duct to the impeller, wherein the impeller is driven by the engine to provide thrust energy to the flow of water through the duct;an outlet that allows water to flow from the jet drive rearward of the watercraft after the impeller has provided thrust energy to the flow of water through the duct;a pressure sensor that senses water pressure in the duct upstream of the impeller and generates a water pressure signal in response thereto; andan electronic controller that controls the operation of the engine and receives the water pressure signal generated by the pressure sensor, wherein the electronic controller limits engine output power to reduce impeller cavitation based on the water pressure signal;wherein the jet drive duct comprises in part a wear ring surrounding the impeller, the wear ring containing an access hole through a wall of the wear ring and the pressure sensor is mounted in fluid communication with the access hole to expose the pressure sensor to water passing through the duct.