| 摘要 |
#CMT# #/CMT# The device has a needle (2) whose end has a head (20) forming valve on a seat (14) supported by an end of a cylindrical body. An actuator (3), made of an electroactive material, has a rod (30) made of a material e.g. magneto-resistive material, and displaces the head to open the valve. A counterweight (34) extends the rod to the rear of the actuator. The needle extends coaxially to the body in the form of a rigid bar and axially resonates when it is subjected to axial pulses at a determined excitation frequency, ranging between 10 to 30 kilo hertz, by the actuator. #CMT# : #/CMT# An independent claim is also included for a method for controlling a fuel injecting device. #CMT#USE : #/CMT# Used for injecting fuel (claimed) in a combustion chamber of an internal combustion engine or in an air intake duct. #CMT#ADVANTAGE : #/CMT# The needle extends coaxially to the cylindrical body in the form of a rigid bar and axially resonates when it is subjected to axial pulses at a determined excitation frequency by the actuator, thus superimposing the vibrating motion of the head to the overall movement of the needle. The position of the head forming valve can be controlled precisely with better response time and the actuator made of electroactive material being in acceptable operating conditions. The length of the bar formed by the needle permits to place the actuator at a distance from the head, so that it is least exposed to the heat from the combustion chamber. The excitation frequency is selected close to a natural mode frequency of the needle in order to obtain a resonance phenomenon by successive compressions and extensions of the needle in the axial direction. The bar formed by the needle resonates axially so as to obtain a displacement mode for the head in the axial direction at the selected excitation frequency. The oscillations obtained from the vibrating motion of the head are simultaneously superimposed on the overall movement of the needle and are used to modulate the fuel output and to control the formation of fine fuel droplets. The rod, when deformed by a signal, takes support at one end against the needle and at the other end against the counterweight. The counterweight extends the rod in order to transmit an essential part of the movement of the rod to the needle. #CMT#DESCRIPTION OF DRAWINGS : #/CMT# The drawing shows a longitudinal sectional view of a fuel injecting device. 2 : Needle 3 : Actuator 14 : Seat 20 : Head 30 : Rod 34 : Counterweight. |
