KR20100037559A - Fuel injection system having high-pressure pumps with magnetically operative suction valve - Google Patents

Abstract

PURPOSE: A fuel injection system equipped with a high pressure pump with a suction valve, which can be magnetically operated, is provided to enable suction valves which are magnetically operated to reduce pressure change in a high pressure storage tank to be individually controlled. CONSTITUTION: A fuel injection system equipped with a high pressure pump with a suction valve comprises a fuel tank(12), a high pressure storage tank(9) and a pump device. The high pressure storage tank supplies fuel to the combustion chamber of the internal combustion engine. The pump device comprises high pressure pumps(1,10,11). The high pressure pumps rapidly supply the fuel from the fuel tank to the high pressure storage tank. Each high pressure pump has a pump room, a piston(2) and a suction valve(5). The pump room is connected to the high pressure storage tank. The piston moves inside the pump room. The suction valve secludes the pump room on the fuel tank.

Description

FUEL INJECTION SYSTEM HAVING HIGH-PRESSURE PUMPS WITH MAGNETICALLY OPERATIVE SUCTION VALVE}

The present invention relates to an internal combustion engine comprising a pump device having a fuel storage tank, a high pressure storage tank for supplying fuel to a combustion chamber of an internal combustion engine, and two or more high pressure pumps for feeding fuel from the fuel storage tank to the high pressure storage tank. Fuel injection device, in particular a fuel injection device for a marine diesel engine, a high pressure storage tank for such a fuel injection device, and a method for supplying fuel to a combustion chamber of an internal combustion engine, in particular a marine diesel engine, by such a fuel injection device. .

BACKGROUND OF THE INVENTION Presupposed types of fuel injectors, which compress fuel to injection pressure by means of a decoupled high pressure pump and inject via fuel injectors into individual combustion chambers, are increasingly used in marine diesel engines. In such common-rail systems, it is also known to operate a high pressure storage tank by one high pressure pump or by a plurality of high pressure pumps.

On the other hand, for example from EP 0 244 340 B1, EP 0 481 964 B2, or DE 100 52 629 A1, or WO 00/61939, feeding by deliberate opening and closing of the intake valve of the high pressure pump for the common-rail fuel injector It is already known to form the intake valve as a magnetic valve in order to influence the amount. However, the mere controllability of the intake valve of the high pressure pump does not fully exploit the potential of the magnetically actuated intake valve to optimize the performance of the fuel injector.

Accordingly, an object of the present invention is to improve a common-rail fuel injection device.

To solve such a problem, the fuel injection device according to the preamble of claim 1 is improved by the features that characterize it. Claim 3 claims a high pressure pump for a common-rail fuel injection device and claim 7 calls for a method of operating such a fuel injection device. The dependent claims relate to preferred additional configurations.

A fuel injector for an internal combustion engine according to the invention, in particular a fuel injector for a marine diesel engine, uses a fuel storage tank for storing fuel at low pressure, in particular at ambient pressure, and fuel therefrom, for example, by means of fuel injectors. It includes a high pressure storage tank that can be supplied to the combustion chamber of the. Between the fuel storage tank and the high pressure storage tank two or more high pressure pumps are arranged in parallel for feeding fuel from the fuel storage tank to the high pressure storage tank, in one preferred configuration one or more feeding pumps between the fuel storage tank and the high pressure storage tank and And / or a boost or boost pump may be arranged.

According to the invention, several high pressure pumps or preferably all high pressure pumps of the pump device are provided with an intake valve (to intake throttle) which can be magnetically operated, wherein the movable piston pushes the pressure to the fuel and preferably The pump chamber, which draws fuel towards the high pressure storage tank by means of a deflected check valve, can be shut off to the fuel storage tank by the intake valve.

Unlike known pump arrangements up to now with manual intake valves, the properties of the fuel injector can be improved by replacing the intake valve with a number of high pressure pumps connected in parallel that can be operated magnetically. .

For example, the magnetically actuated intake valves of the pump device can be individually controlled to reduce pressure fluctuations in the high pressure storage tank.

For that purpose, for example, magnetically actuated intake valves of two or more high pressure pumps of the pump device can be staggered in time and / or closed. As a result, the inflow into or out of each pump chamber is no longer synchronous, but the pressure peaks of the high pressure pumps whose synchronous movement of the pistons are staggered in time so that the pressure peaks in the suction line or feed line The overall pressure peak of can be reduced. It is also possible to open and close the intake valve several times during the intake stroke to reduce pressure fluctuations.

Additionally or alternatively, failure of one high pressure pump of the pump device can be compensated for by extending the opening time of the intake valve of the other high pressure pump. In this way, one pump failure no longer leads directly to the failure of the entire fuel injector or results in an emergency operating condition, which increases the supply volume of the remaining high pressure pumps by prolonging the opening time, resulting in at least overall failure. This can be partially compensated.

The failure of the feed pump or boost pump disposed between the fuel storage tank and the high pressure storage tank, the so-called blackout, also extends the opening time of the magnetically actuated intake valve of one or more of the high pressure pumps of the pump device. You can cope by doing so. Because the magnetically actuated intake valve allows the high pressure pump to feed fuel to the high pressure storage tank through the intake line to supply the internal combustion engine even if there is no or only a small supply line pressure in the intake line. Because it can be maintained.

Additionally or alternatively, the opening time of the magnetically actuated intake valve of the high pressure pump of the pump device can be changed during the work cycle. In this way, the feed rate of the individual high pressure pump can be changed very quickly, for example, so as to rapidly change the feed rate in order to react as quickly as possible to the load change.

For that purpose, according to one aspect of the invention the switching time of the magnetically actuated intake valve of the high pressure pump, i.e. the replacement time between the open and closed positions of the intake valve, is the maximum suction duration of the high pressure pump, i.e. fuel Is less than 10%, preferably less than 5%, very preferably less than 1/30 of the maximum time previously given by the piston movement, from the fuel storage tank into the high pressure storage tank. In one configuration of the invention, such a switching time of the intake valve can be, for example, 4 milliseconds (ms) or less, preferably 1 ms or less.

In EP 0 244 340 B1 and EP 0 481 964 B2 mentioned earlier, the suction valve is a normally open magnetic valve which is closed upon excitation of the magnet, whereas in the high pressure pump according to the invention it can be operated magnetically. The intake valve can be deflected to a closed position by elastic, hydraulic, and / or pneumatic, and can be actively opened by the pull of the anchor by the electromagnet. This ensures that the pump chamber is shut off to the fuel storage tank in the event that the energy supply to the electromagnet is cut off. In addition, the electromagnet only needs to be energized for a short suction duration in the working stroke. In that regard, the electromagnet is designed so that the force applied to the anchor of the magnetic valve can open the suction valve without the supply line at the suction side connection line in order to enable blackout starting even at low supply line pressure.

In order to be able to design and operate a suction valve having a defined force, the anchor chamber of the magnetically actuated suction valve is liquid sealed to the suction connection line or in communication with the suction connection line.

In a fuel injection device for an internal combustion engine according to the present invention, a high pressure storage tank for such a fuel injection device, and a method for supplying fuel to a combustion chamber of an internal combustion engine by such a fuel injection device, a parallel between the fuel storage tank and the high pressure storage tank. Of the two or more high pressure pumps arranged to feed fuel from the fuel storage tank to the high pressure storage tank, or preferably the pump chamber with a suction valve on which all the high pressure pumps can be magnetically actuated. By making it possible to shut off the fuel storage tank by this intake valve, it is possible to improve the characteristics of the fuel injection device. For example, the magnetically actuated intake valves of the pump device can be individually controlled to reduce pressure fluctuations in the high pressure storage tank, and the failure of one high pressure pump of the pump device of the intake valve of the other high pressure pump can be controlled. Compensation can be made by extending the opening time. In this way, one pump failure no longer leads directly to the failure of the entire fuel injector or results in an emergency operating condition. In addition, the failure of the feed pump or boost pump disposed between the fuel storage tank and the high pressure storage tank, so-called blackout, also extends the opening time of the magnetically actuated intake valve of one or more of the high pressure pumps of the pump device. Can cope In addition, by varying the opening time of the magnetically actuated intake valve of the high pressure pump of the pump device during the work cycle, the feed rate of the individual high pressure pumps can be changed very quickly, for example to respond as quickly as possible to load changes. Songdo can be changed suddenly.

Further advantages and features of the invention will become apparent from the dependent claims and the embodiments described hereinafter. For that purpose, a single accompanying drawing is shown, partially schematic.

1 shows a fuel injection device according to one configuration of the invention in the form of a common-rail device for a marine diesel engine (not shown). Such a fuel injector has a fuel storage tank or fuel tank 12 in which diesel fuel is stored under ambient pressure, and fuel is injected under high pressure to inject (not shown) the fuel injectors into the combustion chamber of a marine diesel engine. A high pressure storage tank 9 which is stored.

Three high pressure pumps 1, 10, 11 are arranged in parallel between the fuel storage tank and the high pressure storage tank to feed fuel from the fuel storage tank 12 to the high pressure storage tank 9 to the desired pressure. . Since these three high pressure pumps are almost identical in structure, hereinafter, only the high pressure pump 1 shown in detail in FIG. 1 will be described.

Such a high pressure pump 1 is connected to the fuel storage tank 12 via a suction line 3. Although not shown, a feeding pump and / or boosting pumps may be arranged between the fuel storage tank 12 and the high pressure storage tank 9 to create a constant supply line pressure in the suction line 3.

The high pressure pump 1 has a feed connection line (on the feed side such that the high pressure pump pushes fuel into the high pressure storage tank 9 as soon as the pressure in the feed connection line 4 reaches or exceeds the pressure in the high pressure storage tank 9). 4) and for example via a springed biased check valve 6 to the high pressure storage tank 9.

Between the suction connection line 3 and the pump chamber of the high pressure pump 1 which is periodically enlarged and reduced by a piston 2 reciprocating along a cam contour (not shown), for example, a magnetic valve as an active controllable suction valve. (5) is arranged. Such a magnetic valve 5 comprises a valve cap 5.1 that shuts the pump chamber against the fuel storage tank 12 in the closed position shown in FIG. 1. In such a closed position, the valve cap is deflected by a spring 8 having a spring force that is greater than or at least equal to the sum of the maximum supply line pressure of the suction connection line 3 and the maximum negative pressure in the pump chamber.

The electromagnet 7 is housed in an anchor chamber of the housing of the high pressure pump 1, which is hydraulically connected to the suction connection line 3 via a compensating line. In the anchor chamber, the anchor 5.2 of the magnetic valve 5 is pulled at the time of excitation of the electromagnet 7 to open the magnetic valve while overcoming the biasing force of the spring 8, and thus the corresponding of the piston 2. Upon expansion of the pump chamber volume by movement (downward in FIG. 1), fuel is stored to flow from the fuel storage tank 12 into the pump chamber. When the electromagnet is broken, the spring returns the magnetic valve 5 back to the closed position against the supply line pressure of the inlet connection line 3, so that the inlet valve is closed during the compression step.

The magnetically actuated intake valve 5, which is synchronized in time with the stroke of the piston 2, is opened at least once during the intake phase in which the piston 2 enlarges the pump chamber during operation. The amount of suction can be controlled by the length of the opening stages (individual). Further, the pressure sequence can be equalized by the time sequence of the open position and the closed position, and in particular, the pressure fluctuation can be reduced. For example, first, the intake valve 5 is briefly opened to generate a pressure wave toward the pump chamber. The intake valve, which is closed again at an intermediate time, opens once more in time with such pressure waves reflecting back to the fuel storage tank 12, thus inducing another pressure wave towards the pump chamber. Such pressure waves interfere with reflected pressure waves in the opposite direction, causing the pump chamber to be uniformly filled. Of course, the intake valve may be opened almost once, for example during the intake phase of the high pressure pump 1.

Intake valve during the compression step of feeding fuel to the high pressure storage tank 9 under high pressure via the check valve 6 when the piston 2 shrinks the pump chamber and exceeds the deflection force and the high pressure of the high pressure storage tank 9. (5) is closed. In order to reduce the feed rate while maintaining the stroke of the piston, in addition or alternatively to blocking during the intake phase, the intake valve 5 is opened one or more times during the compression phase to draw fuel into the fuel storage tank 12. You can also send it back.

By changing the control action of the electromagnet 7 during the work cycle, in particular by changing the opening and / or closing timing, it is possible to react very rapidly to the changed load conditions and to rapidly change the feed rate accordingly.

Undesired undesired backflow of the fuel in the inlet connection line 3 and the cavitation occurring therein are also reduced by proper control of the electromagnet 7, for example by premature closing and / or light closing of the intake valve. Can be avoided.

When the feed pump or boost pump (not shown) disposed between the fuel storage tank 12 and the inlet connection line 3 fails (so-called blackout) and the supply line pressure of the inlet connection line 3 drops. Nevertheless, it is possible to fill the pump chamber by the active opening of the magnetically actuated suction valve 5 to feed the fuel to the high pressure storage tank 9 under high pressure.

The pistons of three high pressure pumps 1, 10, 11 which are substantially identical in construction can be driven synchronously or in time staggered along the corresponding cam contours. In particular, when the pistons inhale and feed fuel synchronously in time, the pressure fluctuation can be reduced by individually controlling the intake valves individually. For this purpose, in addition to reducing the pressure fluctuations by opening and closing several times, the opening and / or closing points of the pumps 1, 10, 11 are staggered with each other in time so that all the pumps are fueled sequentially rather than at the same time. May be sucked in or returned from the fuel storage tank 12.

If one pump fails, the feed loss can be compensated at least in part by appropriately controlling the intake valve of the other pump, in particular by extending the opening time during the intake phase.

The anchor chamber communicates with the suction connection line 3 via a compensation line. In this way, the movement of the valve anchor 5.2 does not obstruct the pressure so that the intake valve can be designed and operated with a predetermined force.

The magnetic valve 5 with the electromagnet 7 and the spring 7 may be arranged, for example, on a valve support, but also on a pump cylinder, and in a preferred configuration clamping and guide sleeves (not shown) And the liquid sealing screw cover.

1 is a view showing a fuel injection device according to one configuration of the present invention.

<Explanation of symbols for the main parts of the drawings>

1: high pressure pump 2: piston

3: suction connection line 4: feeding connection line

5: magnetic valve 5.1: valve cap

5.2: valve anchor 6: check valve

7: electromagnet 8: deflection spring

9: high pressure storage tank 10, 11: high pressure pump

12: fuel storage tank

Claims (11)

A fuel storage tank 12, a high pressure storage tank 9 for supplying fuel to a combustion chamber of an internal combustion engine, and two or more high pressure pumps 1, 10, 11 for feeding fuel from the fuel storage tank to the high pressure storage tank. In the fuel injection device for an internal combustion engine comprising a pump device having a), The high pressure pumps of the pump device have a suction valve (or suction throttle) which can be magnetically operated to shut off the pump chamber to the fuel storage tank. 2. A fuel injection device according to claim 1, comprising a control device for individually controlling the magnetically actuated intake valves of the pump device. A pump chamber connected to the high pressure storage tank 9 on the feeding side and a fuel storage tank 12 on the suction side, a piston 2 movable in the pump chamber, and an intake valve 5 for shutting off the pump chamber to the fuel storage tank. In the high pressure pump (1, 10, 11) for a fuel injection device according to claim 1 or 2, comprising: High pressure pump, characterized in that the switching time of the intake valve is less than 1/10 of the maximum suction duration of the high pressure pump. 4. The high pressure pump according to claim 3, wherein the switching time of the intake valve is 4 ms or less. 4. The high pressure according to claim 3, characterized in that the magnetically actuated intake valve is deflected by the elastically to the closed position and can be actively opened by the pull of the anchor 5.2 by the electromagnet 7. Pump. 4. The high pressure pump according to claim 3, characterized in that the anchor chamber of the magnetically actuated suction valve is liquid sealed to the suction connection line (3) or in communication with the suction connection line (3). A method for supplying fuel to a combustion chamber of an internal combustion engine by a fuel injection device according to claim 1, A method of fuel supply, characterized in that the control of the magnetically actuated intake valves (5) of the pump device is individually controlled to reduce pressure fluctuations in the high pressure storage tank (9). 8. A fuel supply method according to claim 7, characterized in that the magnetically actuated intake valves (5) of the two high pressure pumps of the pump arrangement are opened or closed staggered in time. 8. The method of claim 7, wherein the opening time of the magnetically actuated intake valve of the high pressure pump of the pump device is changed during the working cycle. 8. The method of claim 7, wherein if one high pressure pump of the pump device fails, the opening time of the magnetically actuated intake valve of the other one or more high pressure pumps of the pump device is extended. . 8. The method of claim 7, wherein in the event of a failure of the feed pump or booster pump disposed between the fuel storage tank and the high pressure storage tank, the magnetically actuated intake valve of the at least one high pressure pump of the pump device is actively opened. A fuel supply method characterized in that.

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