WO2011047749A1

WO2011047749A1 - Cold start valve

Info

Publication number: WO2011047749A1
Application number: PCT/EP2010/005461
Authority: WO
Inventors: Alexander Steiner
Original assignee: Robert Bosch Gmbh
Priority date: 2009-10-20
Filing date: 2010-09-06
Publication date: 2011-04-28
Also published as: DE102009049995A1; EP2490924A1

Abstract

The invention relates to the design of a cold start valve, comprising a control piston, by means of which an inlet connection and an outlet connection of the cold start valve can be connected so as to permit fluid flow, wherein one control side of the control piston is connected to the outlet connection of the cold start valve and the other control side of the control piston is connected to a control pressure connection of the cold start valve, and in addition force is applied to said other control side of the control piston by means of a pre-loading spring. According to the invention, an additional forced switching mechanism for the sliding of the control piston to connect the inlet connection and the outlet connection is provided, wherein said sliding is carried out in a superimposed or supporting manner (for the control function involving the operating medium).

Description

description

Cold start valve

The present invention relates to a cold start valve according to the preamble of patent claim 1.

Vehicles with internal combustion engines as the main drive device and with a number of hydraulic consumers usually have a feed or charge pump, which is connected via a mechanical transmission with the internal combustion engine and is thus already driven during the starting process of the internal combustion engine. In order to keep the resulting torque load on the starter of the internal combustion engine as small as possible, the feed or charge pump is usually associated with a cold start valve, which temporarily the input and

Output terminal of the feed or charge pump shorts and thus one

Neutral pass causes.

From the prior art, for example according to EP 1 172 588 B1, a cold start valve of this type is known. This is a mechanical valve which, during the starting process of an internal combustion engine, relaxes the charge pressure of a charge pump connected to the internal combustion engine into the hydraulic tank or sump. The cold start valve is temperature sensitive, so that at lower temperatures the charge pump oil is relieved for a longer period of time than at higher temperatures.

Furthermore, there are in the prior art so-called protection valves, which a resource plant example in cold and thus viscous

Protect equipment from damage. Such a protective valve is known for example in the publication "Brueninghaus Hydromatik", page 7/44.

In this case, the protection valve consists of a fluid-controlled

Pressure relief valve, which in a bypass line for a resource filter is interposed. One control side of the pressure relief valve is connected to an upstream side of the filter and another, additionally spring biased control side of the pressure relief valve is connected to a downstream control side of the filter. About the biasing spring, the pressure relief valve is set so that it opens when reaching a certain pressure gradient (pressure difference set to 6 bar) between the upstream and downstream side of the filter and relaxes resources in the resource tank.

As can be seen from the prior art described, I leave with a cold start valve, as it is known from EP 1 172 588 B1, no adequate protective function for the equipment installation, since the structure is designed essentially to facilitate a starting operation of the internal combustion engine , In the case of the protection valve according to the publication "Brueninghaus Hydromatik", on the other hand, the cold start function is limited insofar as the valve is a predetermined one

Maximum pressure drop at the system filter permits, with which still one

Torque load is applied to the starter of the brake motor.

In view of this situation, the object of the present invention is to develop with little design effort known from the prior art protection valve so that adequate protection of the filter and the entire equipment system against high pressures and at the same time a cold start with low torque load for the starter internal combustion engine

is guaranteed.

This task is accomplished by a cold start valve with the characteristics of

Patent claim 1 solved. Further advantageous embodiments of the invention are the subject of the dependent claims.

The core of the invention is therefore in the formation of a

Cold start valve with a control piston, by means of which an input and output port of the cold start valve are fluid-connectable, wherein the one control side of the control piston is connected to the output port of the cold start valve and the other

Control side of the control piston with a control pressure connection of the cold start valve connected and additionally acted upon by a biasing spring.

According to the invention, an additional forced switching mechanism is provided for (the

operating-related control function) provided overlapping or supporting displacement of the control piston for connecting the input and output terminals.

This makes it possible, a already known from the prior art protection valve in the form of a pressure relief valve by additive

Modify with the forced switching mechanism with the additional function of a cold start valve, which is a circuit of the valve in a in the

Substantially unpressurized neutral pass allowed.

The invention will be described below with reference to a preferred

Embodiment with reference to the accompanying drawings explained in more detail.

1 shows the circuit diagram section of an equipment installation of a vehicle driven by an internal combustion engine, relating to the feed pump with a downstream system filter,

2 shows a cross section of a cold start valve according to a first preferred embodiment of the invention,

FIG. 3 shows the cross section of a cold start valve modified to FIG. 2, and FIG. 4 shows the cross section of a cold start valve according to a second preferred embodiment of the invention.

Referring to the accompanying Fig. 1, a feed pump 1 via a

Transmission link or a drive shaft 2 with a not shown

Internal combustion engine or internal combustion engine mechanically connected and is driven by this. An input terminal of the feed pump 1 leads to a

Resource memory 4 or sump and the output port is over one

Supply line 6 connected to the input terminal of a system filter 8. Whose Output terminal is coupled via a main feed line 10 with the equipment not shown.

A bypass line 12 branches off from the supply line 6 immediately upstream of the system filter 8 and leads back to the operating medium store 4 or to the inlet connection of the feed pump 1. In the bypass line 12, a cold start valve 14 is interposed in the form of a resource-operated pressure relief valve. The pressure limiting valve 14 has a first control side x, which is biased by a spring and which is connected to the output terminal of the system filter 8, and a second control side y, which is connected to the bypass line 12 upstream of the pressure relief valve 14. The biasing spring is set to a value such that a pressure gradient or pressure difference which is established on the two sides of the system filter 8 is not predetermined

Exceeds differential pressure value. When this value is reached, the

Pressure relief valve 14 is opened and excess operating fluid pressure upstream of the system filter 8 relaxed in the resource memory 4.

According to the invention, the spring-biased control side is x

Pressure limiting valve 14 is provided with an additional forced switching mechanism 16, via which the pressure relief valve 14 is independent of the height of the pressure gradient switchable into the open position and / or a selectable / adjustable additional force on the corresponding control side x of the pressure relief valve 14 which supports the spring force and thus reduces the maximum allowable value for the pressure gradient.

The positive switching mechanism 16 may be formed in various shapes, such as electric, mechanical, hydraulic, etc., as described in more detail below.

2 and 3, a Elektromagnetmechanismgs 18 is provided which exerts a magnetic force on the control piston 20 of the pressure relief valve 14 in the energized state, which moves the control piston 20 in the direction of its open position. The magnetic force can be so high that this pressure relief valve 14th opens and resources is relaxed or the magnetic force is set so high that the pressure relief valve 14 does not open in normal operation, but the necessary for opening the pressure relief valve 14

Pressure drop at the system filter 8, originally determined by the spring biasing force, is reduced to a lower value.

According to the Fig. 2 or 3, it is structurally provided to modify a known from the prior art pressure relief valve by the at

Control piston 20 of the valve 14 at one control side of an additional

magnetic piston piece or magnetic plunger 22 is attached axially, which extends to an electromagnet 24 which is additive to the housing of the

Pressure relief valve 14 is mounted. The electromagnet 24 may be arranged axially to the magnetic plunger 22 and when energized, a tensile force in

Exercise opening direction on the magnetic plunger 22 (see Fig. 2) or alternatively laterally mounted on the magnetic plunger 22 and when energized a

Exert pressure force in the opening direction on the magnetic plunger 22 (see FIG. 3). In this way, the bypass line 12 by energizing the

Solenoid 24 open regardless of the prevailing pressure gradient on the system filter 8.

Furthermore, the control or valve piston 20 is usually with a

Provided axial bore 26 which connects both control sides of the piston 20 with each other and creates a throttled pressure compensation delayed. In order now to secure the magnetic plunger 22 on the valve piston 20 of the pressure relief valve 14 simply and inexpensively, it is advantageously provided a

Undercut within the axial bore 26 in the region of a control side of the valve piston 20 and a latching edge on the magnetic ram 22 form, wherein the outer diameter of the magnetic plunger 22 is at least partially smaller than the inner diameter of the axial bore 26. The magnetic plunger 22 now only in the axial bore 26 and be moved radially until the

Arresting edge behind the undercut engages and thus an axial force on the

Valve piston is transferable. 4, a second embodiment of the invention is shown. In this case, instead of the solenoid mechanism 18 according to FIGS. 2 and 3, a manually operable lever or slide 28 to the valve piston 20 of the

Pressure limiting valve 14 coupled. This slider 28 protrudes through the

Valve housing in a sealing manner to the outside and is formed or coupled at its free projecting end with a handle. By manual actuation of the handle can thus the valve piston 20 of the pressure relief valve 14 positively displaced into an open position and thus the bypass line 12 for a

Neutral circulation are released during the starting process of the internal combustion engine.

Claims

claims

1. Kaltstartvenil with a control piston (20), by means of a input and

Output terminal of the cold start valve are fluid-connectable, wherein the one

Control side is connected to the output terminal of the Kalttartventils and whose other control side is connected to a control pressure port of the cold start valve and in addition with a biasing force kraftbeaufschlagt, characterized by a forced switching mechanism (16) for superimposed or supporting displacement of the control piston (20) for connecting the input and output terminal.

2. cold start valve according to claim 1, characterized in that the

Forced switching mechanism (16) has an electromechanism (18), consisting of an optionally energizable electromagnet (24) via which a magnetic force on a magnetic plunger (22) can be applied, which is preferably fixed axially on the control piston (20).

3. cold start valve according to claim 2, characterized in that the

Electromagnet (24) is mounted axially to the magnetic plunger (22) on a valve housing to a selectively applied current to the magnetic plunger (22) in

Exercise opening direction of the control piston (20).

4. cold start valve according to claim 2, characterized in that the

Electromagnet (24) is mounted laterally from the magnetic plunger (22) on a valve housing to a selective force to a pressing force on the magnetic plunger (22) in

Exercise opening direction of the control piston (20).

5. cold start valve according to one of the preceding claims, characterized

in that the magnetic plunger (22) is latched on a side of the control piston (20) with this.

6. cold start valve according to claim 5, characterized in that the

Control piston (20) has one of its two control sides connecting axial bore (26), in in the region of a control side, an inner Hinterschneiduhg is formed and the magnetic plunger (22) has a locking edge, which is engageable with the undercut in positive engagement.

7. cold start valve according to claim, characterized in that the

Forced switching mechanism (16) has a slide (28) which is attached to the control piston (20) and manually operable for a displacement of the control piston (20).