Patent Description:
Electromagnetic operated valves are widely known in the art comprising a valve body, electromagnetic driving means, and a plunger member movable by said driving means along a flow direction to operate a closure member relative to a valve seat against pressure of a fluid to enable flow of fluid.

For example, <CIT> discloses an electromagnetically operated valve including an upper valve member loaded by a spring and controlling communication between an air inlet port, connected to a source of compressed air, and an engine port connected to a door engine, and a lower valve member controlling communication between the engine port and an exhaust port and a solenoid secured to the valve. A solenoid plunger is provided to move upwards and downwards to open an air inlet valve and to close an exhaust valve.

A mechanical valve for controlling coolant flow which may be opened and closed by the pressure of a coolant introduced into a coolant inlet is disclosed in <CIT>. The valve comprises a valve housing having a coolant inlet and a coolant outlet, a valve body in the coolant flow space linearly movable by the flow pressure of the coolant introduced into the coolant inlet, and configured to move by the flow pressure of the coolant to close the coolant outlet, and a support spring disposed at the rear of the valve body in the coolant flow space to elastically support the valve body. A support spring is fitted in a coolant flow space formed in the valve housing.

The main drawback of such valves is that the fluid may cause an unauthorized opening of the valve.

Guide rails may be included suitable for guiding the plunger member as it is driven inside the valve body along the flow direction.

A fluid ejection system for cleaning optical surfaces in motor vehicles according to the present invention is defined in claim <NUM>. The fluid ejection system comprises a fluid duct inside of which a fluid can flow. The fluid duct has a duct fluid inlet for receiving fluid from a fluid source, a fluid outlet for discharging the fluid to the outside, and at least one electromagnetically operated valve as described above for regulating the flow of the fluid through the fluid duct. It is envisaged that the fluid ejection system comprises a number of fluid ducts as required fed by at least one fluid source and arranged to discharge a number of corresponding fluid streams. A nozzle may be arranged in each duct fluid outlet for suitably ejecting the fluid. In this respect, it is advantageous if the above described electromagnetically operated valves are included in the nozzles forming electromagnetically operated valve devices. Thus, a number of electromagnetically operated valve devices may be included in the fluid ejection system. Means for controlling the electromagnetically operated valve may be included.

With the above described electromagnetically operated valve and fluid ejection system, fluid flow through a fluid duct is efficiently managed by allowing the fluid to flow by operating an electromagnetic driving means and preventing the fluid from flowing by fluid pressure while pressure in a fluid source is maintained.

Further preferred embodiment of the present invention are defined in the dependent claims.

A significant advantage of the fluid ejection system is that fluid flow opening and closing functions are integrated in nozzles as a result of which no solenoid valve manifold and thus less supplier dependence is required. It has been found that, with the above described fluid ejection system cleaning times and cleaning fluid volume are advantageously reduced. For example, fluid consumption may be reduced by <NUM>% and fluid tank volume may be also reduced by <NUM>%. A further significant advantage of the present fluid ejection system is that all conduits are pressurized until reaching nozzles ensuring efficient fluid delivery. With the present the present fluid ejection device, check valves, pressure valves, or non-spill valves which are typically used in prior art fluid ejection devices may be dispensed with, in particular when liquid is used as fluid.

A non-limiting example of the present disclosure will be described in the following, with reference to the appended drawings, in which:.

<FIG> shows a diagram illustrating one exemplary layout of a fluid ejection system <NUM>. The fluid ejection system <NUM> in the example shown comprises a number of fluid ducts <NUM> through which pressurized fluid F can flow. According to the present invention, the present fluid ejection system <NUM> is applied for cleaning optical surfaces in motor vehicles being the fluid F air or washing liquid.

Fluid ducts <NUM> each having one duct inlet <NUM> and one duct outlet <NUM> are provided for receiving fluid F from a source <NUM> of pressurized fluid F, i.e. a compressed-fluid tank or directly from a fluid compressor. The compressed-fluid tank <NUM> containing fluid F, such as air, under a pressure of about <NUM>-<NUM> bar from the fluid compressor <NUM>. Although one source of pressurized fluid <NUM> has been illustrated in <FIG>, a number of sources of pressurized fluid <NUM> may be provided for feeding one or more fluid ducts <NUM>.

The duct outlet <NUM> is arranged at one free end of each air duct <NUM> for discharging fluid F to the outside through a nozzle <NUM>. Fluid pressure at the duct inlet <NUM> is of the order of <NUM>-<NUM> bar. Fluid ducts <NUM> are thus all pressurized until reaching nozzles <NUM>. The electromagnetically operated valves <NUM> shown in <FIG> of the drawings are, according to the present invention, included in the nozzles <NUM> forming electromagnetically operated valve devices.

A control means <NUM> is also provided for controlling a state of an electromagnetically operated valve <NUM> that serves the purpose of regulating fluid flow through fluid ducts <NUM>.

The above mentioned control means <NUM> may be any intelligent control means such as an electronic control unit (ECU), as shown in <FIG>, for controlling a status of the electromagnetically operated valves <NUM> in response to one or more sensing elements such as a dirt sensor, etc. However, the control means <NUM> may be a manual actuator to control the operation of the electromagnetically operated valve <NUM> as desired by the user or operator.

Now referring to <FIG> of the drawings, a first configuration of the electromagnetically operated valve <NUM> is shown comprising a valve body <NUM> having a valve inlet <NUM> leading to an inlet section <NUM> and a valve outlet <NUM> leading to a corresponding nozzle <NUM>, shown in <FIG>. A mobile core or plunger member <NUM> movable through the inside of the valve body <NUM> is also provided. In the example shown, the plunger member <NUM> has a diameter of and about <NUM>-<NUM> and is <NUM>-<NUM> long. Other sizes are of course possible.

The plunger member <NUM> is driven by electromagnetic driving means <NUM> along a flow direction D inside the valve body <NUM> along an open direction D1 to the left in <FIG> opposed to the fluid flow, as it will be explained below. As stated above, nozzles <NUM> are provided in respective valve body outlets <NUM>.

Still referring to <FIG> of the drawings, the electromagnetic driving means <NUM> in the example shown comprises a coil <NUM> that is arranged surrounding a fixed core or ferromagnetic ring <NUM>. The ferromagnetic ring <NUM> is in turn arranged surrounding the plunger member <NUM>. The ferromagnetic ring <NUM> has a ring inlet <NUM> fluidly connected to the valve inlet <NUM>. As the coil <NUM> is energized through power supply line <NUM> an electromagnetic field is generated. Such electromagnetic field is suitable for causing a magnetic force, for example of the order of <NUM>-<NUM> N, greater than that of the fluid F, to drive the plunger member <NUM> along the open direction D1 to the left in <FIG> as described above, along flow direction D, in the opposite direction to that of the fluid flow. This causes the plunger member <NUM> to move into an open position shown in <FIG> in which fluid F is allowed to flow through the valve body <NUM> into the valve outlet <NUM>. As the coil <NUM> is not energized, the electromagnetic field ceases and the plunger member <NUM> is driven by the pressure of fluid F that flows inside the valve body <NUM> along the closed direction D2, to the right in <FIG> as a result of which fluid F is prevented from flowing into the valve outlet <NUM>. The plunger member <NUM> may be partially hollow with an inner channel <NUM> defined therein.

A plunger member fluid inlet <NUM> is fluidly connected to said ring inlet <NUM> and a number of plunger member fluid outlets <NUM> radially distributed are provided in the plunger member <NUM>. Fluid F may be thus allowed to flow from the plunger member fluid inlet <NUM> to the plunger member fluid outlets <NUM> along flow direction D towards valve outlet <NUM> to be delivered through nozzles <NUM>.

In a second configuration, the plunger member <NUM> is solid as shown in <FIG> of the drawings. In use, in said second configuration, since the plunger member <NUM> is solid, the fluid F flows around the plunger member <NUM> and even may flow around the ferromagnetic ring <NUM>. As in the first example, with the coil <NUM> not being energized, the plunger member <NUM> is driven by the pressure of fluid F that flows inside the valve body <NUM> along the closed direction D2, to the right in figure, as a result of which fluid F is prevented from flowing into the valve outlet <NUM>, and with the coil <NUM> being energized, the plunger member <NUM> is driven by the generated magnetic field along the open direction D1, to the left in figure, as a result of which fluid F is allowed to flow around the plunger member <NUM> and it may be also allowed to flow around the ferromagnetic ring <NUM> into the valve outlet <NUM> to be ejected out through nozzle <NUM>.

A leak-proof sealing cap <NUM> is provided to close the valve body <NUM>. Thus, in the open position of the electromagnetically operated valve <NUM> shown in <FIG>, the sealing cap <NUM> is separated from one end <NUM> of the interior of the valve body <NUM> allowing fluid F to flow towards the valve outlet <NUM>. In the closed position of the electromagnetically operated valve <NUM> shown in <FIG>, the sealing cap <NUM> abuts said end <NUM> of the interior of the valve body <NUM> preventing fluid F from flowing towards the valve outlet <NUM>.

In <FIG>, a preloaded compression closing spring <NUM> is provided inside the valve body <NUM> to bias the plunger member <NUM>. Specifically, the closing spring <NUM> is arranged surrounding the plunger element <NUM> and more particularly the closing spring <NUM> is arranged between the ferromagnetic ring <NUM> and ribs <NUM> formed in the plunger member <NUM>. The closing spring <NUM> is capable of providing a spring force of about <NUM>-<NUM> N in the same direction as the pressure of fluid F flowing inside the valve body <NUM>. The force that can be applied by the coil <NUM> when energized is thus greater than the force of the closing spring <NUM> plus the force of the fluid F flowing through the valve body <NUM>. In operation, the closing spring <NUM> is more extended in the closed position than in the open position biasing the plunger member <NUM> along the same direction D1 as that of the fluid flow direction D to keep the plunger member <NUM> in a closed position, shown in <FIG>, even when not enough or no incoming fluid pressure exists.

An opening spring <NUM>', shown in <FIG>, may be alternatively provided inside the valve body <NUM> to bias the plunger member <NUM> along a direction D1 opposite to that of the fluid flow direction D to counteract the force of the pressurized fluid F flowing through the valve body <NUM>. As a result, high forces are not required to be applied to open the valve body end <NUM>. Said opening spring <NUM>' is more extended in the open position than in the closed position. Biasing force of said opening spring <NUM>' is lower than a fluid pressure such that the plunger member <NUM> is always kept in a closed position by pressurized fluid. In particular, the force that can be applied by the coil <NUM> when energized is thus greater than the force of the fluid F flowing through the valve body <NUM> minus the force of the opening spring <NUM>'.

As a result, a magnetic force required to drive the plunger member <NUM> along the open direction D1 is reduced.

The plunger member <NUM> is guided as it is driven inside the valve body <NUM> along flow direction D according to open and closed directions D1, D2 through the use of the above mentioned ribs <NUM> formed in the plunger member <NUM>. Also, the plunger member <NUM> is guided in use through an inner surface of the ferromagnetic ring <NUM> and an exterior surface of the plunger member <NUM> itself as shown in <FIG> such that the plunger member <NUM> is centered inside the valve body <NUM> during use.

Claim 1:
A fluid ejection system (<NUM>) for cleaning optical surfaces in motor vehicles, the fluid ejection system (<NUM>) comprising:
- a fluid duct (<NUM>) inside of which a fluid (F) can flow, the fluid duct (<NUM>) having a duct inlet (<NUM>) for receiving fluid from a fluid source, a duct outlet (<NUM>) for discharging the fluid (F) to the outside,
- a nozzle (<NUM>) arranged at the duct outlet (<NUM>) for ejecting the fluid (F) to an optical surface of a motor vehicle;
the fluid ejection system (<NUM>) being characterised by the following:
- at least one electromagnetically operated valve (<NUM>) for regulating the flow of the fluid (F) through the fluid duct (<NUM>),
wherein the electromagnetically operated valve (<NUM>) includes a valve body (<NUM>), a plunger member (<NUM>), electromagnetic driving means (<NUM>) for driving the plunger member (<NUM>) along a flow direction (D) inside the valve body (<NUM>) into at least an open position in which a fluid (F) is allowed to flow through the valve body (<NUM>) and into a closed position in which the fluid (F) is not,
wherein the plunger member (<NUM>) is arranged to be forced by a pressure of flowing fluid into the closed position, and to be driven by the electromagnetic driving means (<NUM>) into the open position, and
wherein the electromagnetically operated valve (<NUM>) is included in the nozzle (<NUM>) forming an electromagnetically operated valve device.