CN110637152A

CN110637152A - Device for controlling the compression ratio of an engine with variable compression ratio comprising a two-way solenoid valve with controlled permanent leakage

Info

Publication number: CN110637152A
Application number: CN201880015371.3A
Authority: CN
Inventors: S·比戈; B·泰西耶; F·贝松
Original assignee: Venezuela Rabbi; MCE5 Development SA
Current assignee: Venezuela Rabbi; MCE5 Development SA
Priority date: 2017-03-01
Filing date: 2018-02-28
Publication date: 2019-12-31
Also published as: FR3063519B1; WO2018158540A1; KR20200136804A; FR3063519A1; JP2020509292A

Abstract

The present invention relates to an apparatus for controlling the compression ratio of an engine having a variable compression ratio, the apparatus comprising: an actuating cylinder comprising a piston (111) defining two chambers (112, 113) for receiving pressurized fluid supplied by an accumulator (33), a first fluid line (31A, 32A) and a second fluid line (31B, 32B); the first fluid line (31A, 32A) connects the upper chamber to the accumulator and comprises a first valve assembly (2A); the second fluid line (31B, 32B) connects the lower chamber to an accumulator (33) and comprises a second valve assembly (2B), characterized in that the first fluid line and/or the second fluid line comprises at least a calibrated fluid leakage opening.

Description

Device for controlling the compression ratio of an engine with variable compression ratio comprising a two-way solenoid valve with controlled permanent leakage

Technical Field

The present invention relates to a device for controlling the compression ratio of an engine with variable compression ratio, comprising a control cylinder comprising a piston defining two chambers for receiving pressurized fluid, and an accumulator delivering pressurized fluid to the two chambers through two mutually different fluid lines, each comprising a solenoid valve assembly.

The invention also relates to an engine with variable compression ratio, comprising such a device and a solenoid valve for the operation of such a device.

Background

When the internal combustion engine stops to stop the cooling of the engine, the temperature of some parts of the engine continues to rise. This is the case, for example, of an oil contained in one chamber of the actuating cylinder of an engine with variable compression ratio of the type described in application WO2016/097546, the actuator of which is shown in figure 1. Then, depending on the difference between the initial temperature and the final temperature, the thermal expansion causes an increase in the pressure in the chamber containing the oil. When this pressure exceeds the maximum operating pressure associated with absorbing combustion forces, failure of the oil-containing chamber may result.

To overcome this problem, a common solution is to install a counter-balance relief valve in the lower chamber to vent the excess pressure. However, this solution only works when the cylinder is not in the lower docking position. Furthermore, this solution is still very disruptive to the design of the lower chamber.

The present invention aims to solve these problems by proposing a compression ratio control system for an engine having a variable compression ratio, which prevents the effect of a temperature rise after the engine has been stopped.

Disclosure of Invention

To this end, according to a first aspect, the invention proposes a device for controlling the compression ratio of an engine with variable compression ratio, comprising an actuating cylinder, an accumulator, a first fluid line, a second fluid line, said actuating cylinder comprising a piston defining two chambers for receiving pressurized fluid; the accumulator delivers pressurized fluid; the first fluid line connecting the upper chamber to the accumulator and including a first valve assembly capable of controlling fluid flow in the first fluid line; said second fluid line connecting the lower chamber to the accumulator and comprising a second valve assembly capable of controlling the flow of fluid in said second fluid line, said device being characterized in that the first fluid line and/or the second fluid line has at least one calibrated fluid leakage opening.

Thus, the presence of the leakage opening may generate a permanent leakage of fluid, which ensures the discharge pressure during heating of the fluid even when the motor is stopped.

Preferably, the first fluid line and/or the second fluid line has a bypass conduit arranged to connect one chamber to the accumulator, including a check valve preventing fluid flow from the chamber to the accumulator, said bypass conduit being connected in parallel with the associated valve assembly and the leak opening when the fluid line has such an opening. The presence of a bypass line comprising a check valve in parallel with the leak opening has the following advantages: a permanently controlled leakage of fluid is generated, while preventing any fluctuation of the mean pressure of the chamber.

Advantageously, the leakage opening is calibrated to reduce the pressure in the actuating cylinder in the event of a temperature increase at the stop of the engine.

Advantageously, the leak opening is calibrated to reduce the pressure by discharging a volume of fluid at a rate of 10 to 30cc/min at 100 ℃, 240bar Dp (and preferably at a rate of 20cc/min at 100 ℃, 240bar Dp).

According to a first configuration, the leak opening comprises at least one calibrated hole provided in the wall of a duct, called leak duct, mounted as a bypass on said fluid duct.

Advantageously, the leakage conduit is arranged to form a line in parallel with the fluid line of the chamber to which said leakage conduit is connected.

According to another configuration, provision may be made for a leakage opening to be provided at the valve plug of the associated valve assembly in addition to or instead of the calibrated orifice described above.

Advantageously, the bypass conduit is arranged to form a conduit in parallel with the fluid conduit of the chamber to which it is connected.

Advantageously, a bypass conduit is provided to connect the lower chamber to the accumulator.

According to an advantageous configuration, each fluid line has a leakage conduit.

Advantageously, the first valve assembly and the second valve assembly are connected to the accumulator by a common conduit.

Advantageously, the first and second fluid lines and the first and second valve assemblies are provided with magnetic actuators to form a solenoid valve, so as to be able to open and close simultaneously the upper and lower chambers connected to the solenoid valve.

According to another aspect, the invention relates to a solenoid valve comprising two valve assemblies, each for controlling the flow of fluid delivered under pressure by an accumulator, and a single solenoid actuator, each valve assembly having a valve body comprising a longitudinal passage having an axis AA and communicating with at least two fluid lines, and a valve device; the valve arrangement comprising a piston mounted so as to be movable within the passage between an open position of the fluid lines enabling fluid flow from one fluid line to the other, and a closed position of the fluid lines closing the fluid lines relative to each other, the piston comprising a magnetisable end portion and an end portion opposite the magnetisable end portion, the opposite end portion forming a flap which can bear against the seat to form the closed position; the single electromagnetic actuator is capable of simultaneously controlling the movement of the piston of each valve assembly to an open position of the fluid line; the actuator is interposed between the two valve assemblies and includes an electromagnetic coil having a coil bore that receives a fixed magnetizable target extending opposite the magnetizable end of the piston of each valve assembly; the solenoid valve is characterized in that the first fluid line and/or the second fluid line has at least one calibrated fluid leakage opening.

According to other advantageous and non-limiting features of the invention, taken alone or in any technically feasible combination:

the first fluid line and/or the second fluid line comprise a bypass conduit comprising a check valve preventing fluid flow to the accumulator, said bypass conduit being connected in parallel with the associated valve assembly on the one hand and with such an opening on the other hand when the fluid line comprises a leak opening. The combined presence of a bypass line in parallel with a controlled permanent leak has the advantage of reducing the precision of the work piece and thus the manufacturing costs. This also has the advantage of increasing wear resistance by compensating for leakage. This also reduces the number of parts and reduces cavitation in the lower chamber of the actuating cylinder associated with the solenoid valve.

The leak opening is calibrated to reduce the pressure by discharging a volume of fluid at a rate of 10 to 30cc/min at 100 ℃, 240bar Dp (and preferably at a rate of 20cc/min at 100 ℃, 240bar Dp).

The leakage opening comprises at least one calibrated hole provided in the wall of a duct, called leakage duct, mounted as a bypass on said fluid duct.

-the leak conduit is arranged to form a line in parallel with the fluid line of the chamber connected to the leak conduit.

The leakage opening is provided at the non-return valve of the associated valve assembly.

Each fluid line has a leakage conduit.

The first valve assembly and the second valve assembly are connected to the accumulator by a common conduit.

The calibrated leak opening may result from a programmed periodic opening of the valve assembly.

And when the solenoid valve is connected to an actuating cylinder with two chambers defined by pistons:

the leakage opening is calibrated to reduce the pressure in the actuating cylinder in case of an increase in temperature at engine stop.

-a bypass conduit is arranged to form a line in parallel with the fluid line of the chamber to which the bypass conduit is connected.

A bypass conduit is provided to connect the lower chamber to the accumulator.

The first and second fluid lines and the first and second valve assemblies are provided with magnetic actuators to form a solenoid valve, so as to be able to open and close simultaneously the upper and lower chambers connected to the solenoid valve.

The invention also relates to a variable compression ratio engine comprising an arrangement for controlling the compression ratio as described above.

Drawings

Other objects and advantages of the present invention shall be made apparent from the following description with reference to the accompanying drawings, in which:

figure 1 shows a schematic view of a device for controlling the compression ratio of a variable compression ratio engine of the prior art;

figure 2 shows a schematic view of the device for controlling the compression ratio according to the invention.

For purposes of clarity, the same reference numbers will be used throughout the drawings to refer to the same or like parts of different embodiments.

Detailed Description

In connection with fig. 2, a compression ratio control arrangement is described for controlling the compression ratio of a variable compression ratio engine of the type described in application WO2008/148948, for example.

The compression ratio control apparatus includes an actuating cylinder 110, and the actuating cylinder 110 includes: a piston defining two chambers, an upper chamber 113 and a lower chamber 112, the upper chamber 113 and the lower chamber 112 being supplied with hydraulic fluid (oil in this case) under pressure from the accumulator 33. For this purpose, first fluid lines 31A, 32A and second fluid lines 31B, 32B are provided, the first fluid lines 31A, 32A connecting the upper chamber to the accumulator and comprising a first valve assembly 4A, the second fluid lines 31B, 32B connecting the lower chamber to the accumulator and comprising a second valve assembly 4B.

According to a particular exemplary embodiment, the two fluid lines and the two valve assemblies are provided with magnetic actuators to form a solenoid valve 1 of the type described in application WO2016/097546 and shown in fig. 1, so as to simultaneously open and close the upper and lower chambers.

The solenoid valve 1 will not be described in detail below. However, it includes all of the features of the solenoid valve described in the above-mentioned application. In general, however, the solenoid valve 1 comprises: two valve assemblies 2A, 2B for controlling the flow of fluid, and a single electromagnetic actuator 5 interposed between the two valve assemblies.

Each valve assembly 2A, 2B has a valve body comprising a longitudinal passage 30A, 30B having an axis AA and communicating with at least two fluid conduits 31A, 32A, 31B, 32B. The channels 30A, 30B are open at the actuator 5 side and closed at the side opposite the actuator. Fluid conduits 31A, 32A, 31B, 32B are located on the side walls of the channels 30, 30B. The fluid conduit 31A of the solenoid valve 1 is connected to the upper chamber 113 of the actuating cylinder and the fluid conduit 31B is connected to the lower chamber 112 of the actuating cylinder. The passage 32A is connected to the accumulator 33, while the passage 32B is closed at the end. To ensure fluid communication from the lower chamber 112 to the upper chamber 113 of the actuator cylinder and vice versa, the fluid conduits 32A, 32B are connected to each other by a common channel 34.

Each valve assembly further comprises a valve means. The valve device includes: a piston 4A, 4B, the piston 4A, 4B having a tubular body mounted so as to be movable within the passage 30A, 30B between an open position of the fluid conduits 31A, 32A, 31B, 32B enabling fluid flow from one fluid conduit to the other, and a closed position of the fluid conduits 31A, 32A, 31B, 32B closing the fluid conduits 31A, 32A, 31B, 32B relative to each other. More specifically, each piston 4A, 4B has an end 41A, 41B, said end 41A, 41B being able to abut against a seat 13A, 13B of the end of the channel 30A, 30B furthest with respect to the actuator 5 (i.e. at the closed end of the channel), thereby closing the fluid conduit. Thus, the ends 41A, 41B form a valve flap. The valve is then referred to as an actuated valve. Holes and an opening are provided in the tubular bodies of the end portions 41A, 41B and the pistons 4A, 4B, respectively, to allow the passage of fluid through them. Fluid conduits 31A, 31B are arranged to open onto the channels 30A, 30B opposite the wall portion of the piston provided with the bore, and fluid conduits 32A, 32B are arranged to open onto the channels 30A, 30B near the closed end of the respective channels.

The electromagnetic actuator 5 includes: a cylindrical electromagnetic coil 6 with a coil hole and a part constituting a magnetizable target 8, advantageously made of a magnetizable iron alloy (for example an iron/cobalt alloy, an iron/silicon alloy, etc.), fixedly mounted in said hole. When each piston is moved from a closed position of the fluid conduit to an open position of the fluid conduit under the control of the electromagnetic actuator, each piston 4A, 4B moves in the respective channel towards the target part to abut the respective end face of the target part 8.

The solenoid valve 1 thus constitutes a two-way solenoid valve, ensuring the opening or closing of the fluid lines of the double-valve assemblies 2A, 2B by moving the two pistons 4A, 4B simultaneously according to the magnetic field generated by the coil 6. The fluid path 36 is similar to that of the control device shown in fig. 1. The compression ratio of the motor is controlled by the solenoid valve 1 controlling the flow of pressurized fluid from one chamber of the actuator cylinder 110 to the other and in the opposite direction.

In order to reduce the pressure when the engine is shut off and the temperature rises, the solenoid valve 1 must be provided with at least one leakage opening.

In the schematic diagram of the compression ratio control system shown in fig. 2, the leakage opening 61 is provided in two further conduits, hereinafter referred to as leakage conduits 60, which are by-passed by the first and second fluid lines 31A, 32A, 31B, 32B, respectively.

The leak openings 61 consist of at least one calibrated hole provided in the wall of each duct 60. Each leak conduit 60 is arranged to form a conduit in parallel with the fluid conduits 31A, 32A, 31B, 32B of the chamber to which the leak conduit is connected, and more particularly in parallel with the associated valve assembly.

In order to compensate for the pressure drop of the chamber being lower than the pressure of the accumulator 33 due to permanent leakage occurring in the solenoid valve 1, at least one of the fluid lines is advantageously provided with a bypass conduit 50 comprising a check valve 51. Thus, the presence of the check valve enables refilling of one chamber. The bypass line can thus ensure that the average pressure in the chamber is at least equal to the pressure in the accumulator and optimize the operation of the engine. Of course, this is an exemplary embodiment, as the control device according to the invention may be without any check valve.

In the embodiment shown, a bypass conduit 50 is provided to connect the fluid conduit 31B leading to the lower chamber 112 to the fluid conduit 32B leading to the accumulator 33. Thereby forming a bypass conduit 50 for the second (or lower) fluid line. The bypass conduit 50 is arranged to form a conduit in parallel with the fluid conduit of the chamber to which the bypass conduit 50 is connected, and more particularly in parallel with the associated valve assembly.

In the example shown, the control system comprises two leak lines 60 and a bypass duct 50, said leak lines 60 being mounted by-pass on each fluid line 31A, 32A, 31B, 32B; the bypass conduit 50 is designed to refill the lower chamber 112 and is installed in parallel with the leak conduit of the lower chamber 112. This is a preferred embodiment. It is clear that the invention is not limited to this arrangement and that it is possible to provide the compression ratio control device with a bypass line 50 designed to refill the upper chamber 113. Thus, a bypass conduit 50 including a check valve 51 is provided to connect the fluid conduit 31A leading to the upper chamber 113 to the fluid conduit 32B leading to the accumulator 33. Thereby forming a bypass conduit 50 of the first fluid line (or upper fluid line). Similarly, the compression ratio control means may be arranged to comprise a combined arrangement of the two bypass lines 50 described previously, in such a way that either chamber can be refilled, without going beyond the scope of the present invention. It may also be provided that only one fluid line will be equipped with a leakage line 60.

Permanent leakage may also be provided by providing a clearance between the valve assembly 2B and/or the piston 41B, 41A of the valve assembly 2A and the associated seat 13B, 13A when the solenoid valve is in the closed position. This arrangement may be made to replace or supplement the leakage conduit 60.

According to another embodiment, it may be planned to program the periodic opening of the solenoid valve 1 to a period such that: the temperature of the motor is ensured to be stable so as to limit the influence of temperature rise after the motor is stopped. For example, consider a solenoid valve programmed to open twice per minute over a period of 15 minutes. This programming of the solenoid valve opening may be implemented as an alternative to or in combination with the permanent leakage through the leakage conduit as described above and/or the associated clearance between the valve and the seat.

The above description of the invention is intended to be illustrative. It should be understood that those skilled in the art will be able to create different alternative embodiments of the invention without departing from the scope of the invention.

Claims

1. An apparatus for controlling a compression ratio of an engine having a variable compression ratio, comprising: an actuator cylinder (110), an accumulator (33), a first fluid line (31A, 32A) and a second fluid line (31B, 32B), the actuator cylinder (110) comprising a piston (111) defining two chambers (112, 113) for receiving pressurized fluid; the accumulator (33) delivering a pressurized fluid; the first fluid line (31A, 32A) connects an upper chamber (113) to an accumulator and comprises a first valve assembly (2A) capable of controlling a fluid flow in the first fluid line; said second fluid line (31B, 32B) connecting the lower chamber (112) to the accumulator (33) and comprising a second valve assembly (2B) capable of controlling the fluid flow in said second fluid line, characterized in that the first fluid line and/or the second fluid line comprises at least one calibrated fluid leakage opening (61).

2. Arrangement for controlling a compression ratio according to claim 1, characterised in that the first and/or second fluid line (31A, 32A, 31B, 32B) comprises a bypass conduit (50), which bypass conduit (50) is arranged to connect one of the chambers (112, 113) to the accumulator (33) and comprises a check valve (51) preventing fluid flow from the chamber to the accumulator, which bypass conduit (50) is connected in parallel with the associated valve assembly, and which bypass conduit (50) is connected in parallel with the leakage opening when the first and/or second fluid line (31A, 32A, 31B, 32B) has an opening.

3. An arrangement for controlling a compression ratio according to claim 1 or 2, characterised in that the leakage opening (61) is calibrated to reduce the pressure existing in the actuating cylinder in the event of a temperature increase at engine stop.

4. An arrangement for controlling a compression ratio according to any one of the preceding claims characterized in that the leakage opening (61) is calibrated to reduce the pressure by discharging a volume of fluid at a rate of 10 to 30cc/min at 100 ℃, 240bar Dp.

5. Device for controlling the compression ratio according to any one of the preceding claims, characterized in that said leakage opening (61) comprises at least one calibrated hole provided in the wall of a duct, called leakage duct (60), this leakage duct (60) being mounted as a bypass on said fluid duct (31A, 32A, 31B, 32B).

6. Device for controlling the compression ratio according to the preceding claim, characterized in that said leakage duct (60) is arranged as a duct parallel to the fluid ducts (31A, 32A, 31B, 32B) forming the chamber connected to said leakage duct (60).

7. Device for controlling a compression ratio according to any one of the preceding claims, characterized in that said leakage opening (61) is provided at the plug of the associated valve assembly.

8. Arrangement for controlling the compression ratio according to any one of the preceding claims, characterized in that each fluid line (31A, 32A, 31B, 32B) comprises a leakage conduit.

9. An arrangement for controlling a compression ratio according to any one of the preceding claims, characterized in that the first valve assembly (2A) and the second valve assembly (2B) are connected to an accumulator (33) by a common conduit (34).

10. Device for controlling the compression ratio according to any one of the previous claims, characterised in that the first and second fluid lines (31A, 32A, 31B, 32B) and the first and second valve assemblies (2A, 2B) are provided with a magnetic actuator (8) to form the solenoid valve (1) so as to be able to open and close simultaneously the upper and lower chambers connected to the solenoid valve (1).

11. A solenoid valve (1) comprising: two valve assemblies (2A, 2B) and a single electromagnetic actuator (5), each valve assembly for controlling the flow of fluid delivered under pressure by the accumulator, each valve assembly (2A, 2B) having a valve body comprising a longitudinal channel (30A, 30B) having an axis AA and communicating with at least two fluid lines (31A, 32A, 31B, 32B), and a valve device; the valve device comprises a piston (4A, 4B), the piston (4A, 4B) being mounted so as to be movable within a passage (30A, 30B) between an open position of the fluid lines (31A, 32A, 31B, 32B) enabling fluid flow from one to the other and a closed position of the fluid lines (31A, 32A, 31B, 32B) closing the fluid lines with respect to each other, the piston (4A, 4B) comprising a magnetisable end (40A, 40B) and an end opposite the magnetisable end (40A, 40B), the opposite end forming a flap which can abut against the seat (13A, 13B) to form the closed position; the single electromagnetic actuator (5) is capable of simultaneously controlling the movement of the piston (4A, 4B) of each valve assembly to an open position of the fluid line (31A, 32A, 31B, 32B), the actuator being interposed between the two valve assemblies and comprising an electromagnetic coil (6), the electromagnetic coil (6) having a coil bore accommodating a fixed magnetizable target (8) extending opposite the magnetizable end of the piston (4A, 4B) of each valve assembly (2A, 2B); characterized in that the first fluid line and/or the second fluid line has at least a calibrated fluid leakage opening.

12. Solenoid valve (1) according to claim 11, characterized in that the first and/or second fluid line comprises a bypass conduit (50), the bypass conduit (50) comprising a check valve (51) preventing fluid flow to the accumulator, the bypass conduit (50) being connected in parallel with the associated valve assembly and in parallel with the leakage opening when the first and/or second fluid line (31A, 32A, 31B, 32B) has an opening.

13. A variable compression ratio engine comprising an apparatus for controlling a compression ratio according to any one of claims 1 to 10.