摘要:
An injector with an adjustable-metering servo valve is provided. The injector has a shutter actuated by an armature of an electromagnet. The armature is mobile for an opening stroke defined by a surface of the core of the electromagnet, which is fixed in the casing by a ring nut and a hollow support of the core. The hollow support has a first contact surface that acts on a flange of the core. Set between the surface and a shoulder of the casing is a shim. An annular projection, having a second contact surface, is set between the surface and a shoulder of the casing. The second contact surface is contained at least in part in the area corresponding to the first contact surface so that the stroke of the armature is adjusted by plastic deformation of the shim or of the surface of the core.
摘要:
An injector with an adjustable-metering servo valve is provided. The injector has a shutter actuated by an armature of an electromagnet. The armature is mobile for an opening stroke defined by a surface of the core of the electromagnet, which is fixed in the casing by a ring nut and a hollow support of the core. The hollow support has a first contact surface that acts on a flange of the core. Set between the surface and a shoulder of the casing is a shim. An annular projection, having a second contact surface, is set between the surface and a shoulder of the casing. The second contact surface is contained at least in part in the area corresponding to the first contact surface so that the stroke of the armature is adjusted by plastic deformation of the shim or of the surface of the core.
摘要:
A fuel injector comprising a hollow body for housing a metering valve with a calibrated pipe for outlet of the fuel from a control chamber. The calibrated pipe is normally kept closed by a shutter controlled by an electromagnet comprising a magnetic core and an electric coil housed in an annular slot of the core. The coil outer cylindrical surface forms a gap with the annular slot so as to be lapped by the fuel coming out of the calibrated pipe. The coil comprises a bobbin having a pair of appendages for supporting electric supply plugs, which are englobed at least in part in a block of non-magnetic material. The bobbin has a substantially cylindrical rib, one flange adjacent to an end portion of the plugs, and another flange having a smaller diameter that forms a passage for the fuel between the calibrated pipe and the gap.
摘要:
The injection system comprises a high-pressure pump (7) with variable flowrate, having a number of pumping elements (18) actuated with reciprocating motion and provided each with a corresponding intake valve (22). An accumulation volume (28) is supplied with fuel at low pressure from an intake pipe (10) of the pump (7) through a solenoid valve (31) controlled as a function of the operating conditions of the engine (2). The accumulation volume (28) is in communication with the intake valves (22) through corresponding outlet holes (29), and the solenoid valve (31) is provided with nebulizer holes (36) such as to generate corresponding jets of fuel, each directed towards at least one of said outlet holes (29).
摘要:
A fuel injector comprising a hollow body for housing a metering valve with a calibrated pipe for outlet of the fuel from a control chamber. The calibrated pipe is normally kept closed by a shutter controlled by an electromagnet comprising a magnetic core and an electric coil housed in an annular slot of the core. The coil outer cylindrical surface forms a gap with the annular slot so as to be lapped by the fuel coming out of the calibrated pipe. The coil comprises a bobbin having a pair of appendages for supporting electric supply plugs, which are englobed at least in part in a block of non-magnetic material. The bobbin has a substantially cylindrical rib, one flange adjacent to an end portion of the plugs, and another flange having a smaller diameter that forms a passage for the fuel between the calibrated pipe and the gap.
摘要:
The injection system comprises a high-pressure pump (7) with variable flowrate, having a number of pumping elements (18) actuated with reciprocating motion and provided each with a corresponding intake valve (22). An accumulation volume (28) is supplied with fuel at low pressure from an intake pipe (10) of the pump (7) through a solenoid valve (31) controlled as a function of the operating conditions of the engine (2). The accumulation volume (28) is in communication with the intake valves (22) through corresponding outlet holes (29), and the solenoid valve (31) is provided with nebulizer holes (36) such as to generate corresponding jets of fuel, each directed towards at least one of said outlet holes (29).
摘要:
The injector comprises a balanced metering servovalve to control a rod for the opening/closing of a nozzle. La servovalve has a valve body with a control chamber radially delimited by a tubular portion and fitted with an outlet passage that is opened/closed by an axially movable shutter. The servovalve is also integral with an axial stem, provided with a lateral surface, through which the outlet channel exits. The shutter is coupled to the stem in an axially sliding manner and, when it closes the outlet passage, it is subjected to substantially null axial fuel pressure. The outlet passage has a calibrated segment distanced from the shutter and close to a bottom wall of the control chamber. The calibrated segment is carried by an element fixed to the valve body in correspondence to an axial segment of the outlet passage.
摘要:
A metering servovalve for a fuel injector of an internal combustion engine has an electro-actuator and a fixed valve body, which defines a control chamber communicating with an inlet and with an outlet channel. The outlet channel has at least one calibrated restriction and exits through the lateral surface of an axial stem, on which a sleeve slides, in a substantially fluid-tight manner, to open/close the outlet channel and so vary the pressure in the control chamber. The outlet channel is closed by an end portion of the sleeve that is elastically deformable in a radially outward direction, under the thrust of the fuel pressure, to increase the diameter at which the seal against the valve body is formed, with respect to a non-deformed state, and to generate an axial unbalancing force on the sleeve upon opening when the outlet channel is closed.
摘要:
The metering servo valve comprises a valve body, an open/close element, and an electromagnet, and is housed in a shell of the injector. The electromagnet actuates a mobile armature for a travel defined by an arrest element, carried by the electromagnet, which is housed in a casing, fixed in the shell by means of a threaded ring nut. Said ring nut is screwed with a pre-set tightening torque on a thread of the shell. The casing has a resting surface designed to engage a shoulder of the shell. The surface is carried by an area of the casing designed to undergo deformation as a function of the tightening torque of the ring nut so as to enable fine adjustment of the travel of the armature.
摘要:
A metering servovalve for a fuel injector of an internal combustion engine has an electro-actuator and a fixed valve body, which defines a control chamber communicating with an inlet and with an outlet channel. The outlet channel has at least one calibrated restriction and exits through the lateral surface of an axial stem, on which a sleeve slides, in a substantially fluid-tight manner, to open/close the outlet channel and so vary the pressure in the control chamber. The outlet channel is closed by an end portion of the sleeve that is elastically deformable in a radially outward direction, under the thrust of the fuel pressure, to increase the diameter at which the seal against the valve body is formed, with respect to a non-deformed state, and to generate a radial unbalancing force on the sleeve upon opening when the outlet channel is closed.