CZ82293A3 - Cold start fuel injection pump - Google Patents

Abstract

A cold-starting device for a fuel-injection pump comprises a hydraulic tappet (1) connected to a feed pump (14) via a fluid line (13) having a non-return valve (17), a fluid pressure accumulator (18) and a control valve (19) connected in series. The fluid pressure accumulator (18) has a latch mechanism (45) which, with the actuating means (20) of the control valve (19), is connected to an ignition switch (33), At start-up of the associated engine the ignition switch is moved to position (332) and on to position (333). Such action causes opening of the valve (19) and release of the accumulator's latch mechanism (45). Hydraulic fluid is thus expelled from the accumulator (18) to move the tappet to the start position (a) for advanced injection. Expansion of a unit (35) occurs during engine warm up and this changes over the valve (19) and causes re-charging and latching of <IMAGE>

Description

Cold start devices for fuel injection pumps

BACKGROUND OF THE INVENTION The invention relates to a device for cold starting for fuel injection pumps according to the preamble of the main claim, which is applicable to single-cylinder and multi-cylinder internal combustion engines, for example in motor vehicles.

DE-OS 29 32 672 discloses a cold-starting device of the type mentioned in which a non-return valve and a control valve are arranged downstream of the pressure pump and a pressure reservoir is provided between them, which increases the opening of a relatively large flow diameter in the control valve. the amount of oil fed to the hydraulic tappet. Despite the fact that the pressure reservoir is arranged laterally from the pipeline itself and therefore requires connecting means to be connected to the pipeline, the pressure ratios during feeding are not sufficiently defined. In such a cold-start device, a suddenly maximum oil gap acts with the desired, i.e., sufficiently high, fluid pressure for a period of time in the hydraulic tappet to produce a defined timely adjustment, and that the oil gap is at a certain temperature again loses, that is, 3Θ becomes zero.

The invention makes it possible to maintain the defined pressure pores during the entire injection of liquid into the hydraulic tappet and to accumulate a maximum matched amount of fuel in the fuel pressure reservoir. The engagement lock allows complete disengagement of the fuel tank when the engine is sufficiently warm. Assigning the magnet to the control valve ensures fast and reliable operation.

The connection of the cold-starting device to the ignition switch, which is at the same time the ignition switch of the motor vehicle, enables simple operation. Preferably, the wiring is designed such that, in addition to switching off the ignition switch, the first switch position provides for opening the solenoid valve and the second switch position for releasing the fuel pressure reservoir.

If the cold start conditions no longer apply, that is, if the engine has already reached a satisfactory temperature, the expansion unit, for example a temperature-dependent sensor for temperature expansion, acts on the 3-switch which controls the efficiency of the cold start device. the valve and locks the pushed-in piston back to its initial position.

As with the control valve, an electromagnet can also be provided on the latch block for actuation. In this case, the locking device can act on a rod which is fixed on the piston and which protrudes from the cylindrical pressure reservoir or can act directly on the piston through the cylinder.

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The invention is explained in more detail below with reference to the drawing.

Two exemplary embodiments of a cold set according to the invention are explained in more detail in conjunction with the schematic drawings.

FIG. 1 shows schematically a first embodiment of a device for lowering. cold according to the invention.

FIG. 2 schematically illustrates the fuel pressure reservoir of the second exemplary embodiment, and FIG. 3 shows the fuel tank of FIG. 2 in another engagement position.

DETAILED DESCRIPTION OF THE INVENTION

Fig. 1 shows the hydraulic tappet 1, with the roller 3, weighing the cam 2, with the tappet body 5, slidably mounted in the housing 4, with the piston U of the tappet, with another in the tappet body 5, with a cover plate 2 it is partially embedded in the tappet body 4, which is loaded by a compression spring 10 and which has the shape of a housing, as well as the shoe 81 of the piston 3. which abuts the piston against the tappets by means of a spring cup 44. The compression spring j) rests on the barley 3 on the cover plate 2 and on the other hand on the spring cup 44, which axially fixes the foot 31 of the piston 13. .The pin 11 serves to secure the plunger piston proti against rotation. The fuel channel 12 in the housing 4 and in the tappet body 5 serves to supply a liquid which can widen the gap 43 which acts as a pressure space and which has already been partially formed between the tappet body j and the tappet piston ii by adjacent faces 5 of the plunger 4 and the plunger piston 6 may move apart from the plunger 6 of the plunger up to a specified value a. All parts of the plunger 1 are aligned coaxially with respect to the longitudinal axis XX of the piston 3 of the pump.

The hydraulic tappet 1 is connected via a fuel line 13 to a fuel pump 14 which is part of an internal combustion engine (not shown) and to which a storage tank 15 is associated. In the fuel line 13, which is arranged downstream of the fuel pump 14, modified branch 16 to other systems. this is to the non-return valve 17, to the fuel pressure reservoir 18 and to the actuator of the three-port and two-position valve 19, which is actuated by an electromagnet 20. The valve 19 is configured as a three-port and two-position solenoid valve.

The fuel pressure reservoir 18 is formed by a cylinder 21. in which a piston 23 is movable in the direction of the arrow 24, which cooperates with a compression spring 22. The piston 23 is fixed with a piston rod 25 which protrudes from the cylinder 21 and extends into a housing 26 partially and in which a tappet 29 operable by an electromagnet 27 and a spring 28 is provided, corresponding to a latch recess 30 on the piston rod 25. The housing 26, the electromagnet 37, the latch 28, the latch 29 and the latch recess 30 together form a latching locking device 45.

From a direct current source 31, which is formed, for example, by a vehicle battery with a voltage of 12 volts, the power line 32 leads to an ignition switch 33 which can assume three switch positions 331, 332. 333. of which switch position 331 means off. From the two remaining switch positions 332, 333, line 321 leads to solenoid control valve 19 through line 321 and line 322 to solenoid 27, which allows control of solenoid valve 19 and latch 45. unit 35, which is formed, for example, by a stretch sensor, which, when the engine is warm, elongates to ensure that the limit switch 34 is properly connected.

In the position shown in FIG. 1, the start device is cold prior to start-up, that is, the ignition switch 33 is off in the switch position 331, the control valve 19 is closed, and the cylinder 21 is filled with fuel that cannot escape despite check valve 17 to the fuel pump 14, not even via the control valve 19 to the hydraulic tappet χ. If, as is normally the case with cold starting, the ignition switch 33 is brought from switch 331 to switch 332 and immediately thereafter to switch 333, then the solenoid control valve 19 and the latch 26 to 30 are gradually opened so that the fuel it can pass unrestrictedly from the fuel line 13 through the control valve 19 and the fuel channel 12 to the hydraulic tappet 11. This fuel, which enters from the fuel line 13 to the hydraulic tappet X at a pressure of three to four bars, also includes fuel from the fuel pressure reservoir 13, which is pushed out by the piston 23, the piston 23 being pushed in the cylinder 21 by spring 22 as shown on the left. Since the fuel cannot escape from the hydraulic tappet X, a gap 43 is created between the tappet piston 6 and the tappet body 5, which is filled with fuel at a sufficiently high pressure and large enough to reach the corresponding earlier fuel injection When the oil is injected into the hydraulic tappet 8, the tappet piston 8 is raised against the biasing force of the compression spring 9 3 with its front face above the 3contacting surface of the tappet body 2 by a value. wherein the expansion unit 35 is drawn through the heating of an otherwise not illustrated internal combustion engine to the extent that it actuates the limiting switch 34 thereby disengaging the solenoid 20 and the latch 45 so that the control valve 19 is switched so that oil from the gap not shown 2 stroke The piston 23 in the cylinder 21 is pushed against the force of the compression spring 22 according to the drawing to the right by the oil pressure generated by the fuel pump 14 and is finally locked by a positive closure between the tip of the tappet 29 and In this way, the oil or liquid fuel pressure required for the next cold start is generated in the cylinder 21.

Referring again to Figs. 2 and 3, there is shown a fuel pressure reservoir 36 with a cylinder 37 and a felt 39 which is pressurized by a helical spring 38. The cylinder 37 has fuel lines 40 for the fluid inlet and outlet coming from the fuel pump 14. 1, and is directed to the control valve 19 as shown in FIG. 1. The latch 41 is provided directly on the cylinder 37, its tappet 42 protruding into the cylinder 37 in the locking position shown in FIG. 2 and prevents the piston 39 moving to the left. If the plunger 42 is pulled by the electro magnet 46, the leftward movement of the piston is possible as it passes over the plunger 42 as shown in FIG. 3.

In the state of the art, the activity is similar to that described in connection with Fig. 1 »

Claims (8)

PATENTOVÉ NÁHOKY Cold start device for fuel injection pumps, in which a hydraulic tappet is connected to a fuel pump by means of a fuel line in which a non-return valve, a fuel pressure reservoir and a control valve are provided, characterized in that the fuel pressure reservoir (18) 36) is provided with a latching blocking device (41, 45) which, like the control means (20) of the control valve (19), is connected to the ignition switch (33). Cold start device according to claim 1, characterized in that the fuel pressure reservoir (13, 36) is provided with a piston (23, 39) which is held against the pressure of the fuel in the fuel line (13, 40) by a spring (22). 38), the force of which is less than the fuel pressure in the operation of a warm internal combustion engine. Cold start device according to claim 1 or 2, characterized in that the control valve (19) is designed as a solenoid valve. Cold start device according to at least one of claims 1 to 3, characterized in that it comprises at least one ignition switch (33) having at least three switching positions (331, 332, 333), one of which is connected to control valve (19) and others with fuel pressure reservoir (13, 36 J, Cold-starting device according to claim 4, characterized in that in the connecting conduits (321, 322) between the ignition switch (33) and the control valve (13) or between the fuel pressure reservoir (18, 38) ) a limit switch (34) is provided which is connected to the expansion unit (35), 6. A device for lowering cold according to claim 1 or 2, characterized in that the fuel pressure accumulator (18, 38) is assigned a detent locking device (41, 45) _e The cold-starting device according to claim 6, characterized in that the latching locking means (45) acts on the piston rod (25) on the piston (23) of the fuel pressure reservoir (18). Cold start device according to claim 6, characterized in that the latch (41) is arranged on the cylinder (37) of the fuel pressure reservoir (33) and acts directly on the piston (33). 622-93 » X GIANT. 1 GIANT. 2 «22-33 /// r-MP-732-93-Ce Seamless state of the art SUMMARY OF THE INVENTION The present invention relates to a jointless condition consisting of a warp yarn feeder, a heddle of leaves whose stitch yarn guides pass, yarn feeder yarn feeders for forming false edges, and / or binder yarns for forming the night edges of the fabric. to the edge of the fabric formed by passing through the heald leaves, the mesh guides of the false edge forming device and the binding device and the respective teeth of the paprika fixed in the bidlen, also passing through the warp pairs, and further comprising two supports of said lattices moving vertically in reciprocating motion / affected to the state. BACKGROUND OF THE INVENTION) As is well known in the art, fabric formation requires the use of false-edge yarns to keep the clogged weft yarn under tension, as well as binder yarns to form the side edges of the fabric. While the binder yarns are always fed by bobbins independent of the feed spool / warp yarn, the false-edge yarns can be fed from said feed spool when it is the same type of yarn as the warp yarn, but in modern seamless conditions these are the false-edge yarns are also fed preferably from spools independent of the feed spindle, to allow them to be tensioned differently from the warp yarn or to allow the use of yarns / inferior quality and therefore stronger than the warp yarn. All binder yarns and yarn for making false