MXPA97008109A - Automatic valve for the admission collector of an inte combustion engine - Google Patents

Abstract

The present invention relates to an air intake bleed valve for the intake manifold of an internal combustion engine, comprising a valve seat and a valve closure element pushed towards the valve seat, wherein one of the closure and the seat is made of a material of non-polar plastic, and the other of the closure and the seat is formed of a plastic material pol

Description

"AUTOMATIC VALVE FOR THE ADMISSION MANIFOLD OF AN INTERNAL COMBUSTION ENGINE" The present invention relates to an automatic purge valve. It is especially suitable for fixing to the intake manifold of an internal combustion engine. The principle of "air purge" has been known for many years. This principle states that by admitting a small amount of additional air into the intake manifold of an internal combustion engine, sometimes of particularly low pressure (high vacuum), for example, during moments of acceleration or deceleration of the engine, allows combustion of fuel significantly more efficient inside engine. This, in theory, should reduce the emission of pollutants such as carbon monoxide (CO) and unburned hydrocarbons (HC). However, according to the inventor's good understanding, no commercially useful modality of this principle has been produced. This is essentially because the reaction time of a purge air supply must be extremely small, in order to sustain variations in the vacuum in the intake manifold. As an example, the period during which the air must be supplied is of the order of tens of milliseconds. Initial examples of this principle can be found in Patent Number GB496409 of 1937 and Number GB690635 of 1950. These devices do not appear to have become common in the industry. Patent Nos. GB 2129869 and GB No. 2213875 propose provisions in which a non-return valve based on a spherical bearing is positioned to supply purge air to the intake manifold. The spherical bearing is pushed towards a valve seat by a spring. However, the response time of these versions is less than desirable and, in addition, the reductions of CO and HC achieved are disappointing even taking into account the lowest response time. In recent times, attention has been directed to computer-based engine management (EMS) systems. These are essentially microprocessors supplied with data from a number of sensors distributed around the motor. The EMS observes this data and compares it with the pre-graduated data and / or algorithms and actively manages certain variables in order to optimize the fuel combustion characteristics. However, this system will inevitably be reactive since an imbalance must first be detected and then corrected after it has existed for a certain period. Therefore, the efficiency of these systems is inherently limited by their processing times. The recent attention has therefore been directed to provide even better response times for an existing EMS. The present invention provides a useful working mode of the principle of air purge. In doing so, it proposes a number of deviations from the existing provisions. The present invention therefore provides, in its first aspect, an air intake valve for the intake manifold of an internal combustion engine, comprising a valve seat and a valve closure, the seat and the closure having surfaces conical overlaps formed complementarily, the closure being pushed towards the seat by means of a thrust means acting on the face of the closure placed remote from the seat. It is preferable if, in this arrangement, the pushing means is placed to leeward of the valve closure in order to limit the disturbance of the air flow through the closure.

A suitable thrust means is a compression spring. In that case, it is preferred that the compression spring only holds the valve closure. This can make it easier to place the spring to the leeward of the closure, and usually reduces the number of parts within the potential air flow path of the valve. In its second aspect, the present invention provides an air intake bleed valve for the intake manifold of an internal combustion engine, comprising a valve seat member and a valve closure element pushed towards the valve seat member, the seat member and the closure element being enclosed within a housing, wherein the valve seat member is capable of being located within that housing in any of a plurality of longitudinally offset positions with respect to the thrust of the valve closure element. In this way, the thrust resistance of the valve closure can be varied, together with the internal volume behind the valve arrangement. This allows the arrangement to be tuned to a specific motor. Even though the ideal air fuel ratio is 14.7 to 1, an individual motor can be graduated to operate between 10 and 1 and 12 to 1, to provide smooth and robust operation. The exact ratio for which a specific motor is rated, will usually differ from the next motor in the line. Therefore, the exact pressure in the intake manifold that corresponds to normal operation, steep acceleration and pronounced deceleration, will vary from engine to engine. By this aspect of the present invention, the intake valve can therefore be tuned to reflect this. Preferably, the valve seat is longitudinally movable by rotation of the screw thread arrangement. Ideally, screw threads will be external to the seat and internal within a cylindrical bore in the housing. Appropriately, the seat can be disk configuration. Therefore, the adjusting screw can be locked securely within the housing. This prevents unauthorized tampering and allows the seller of the item to provide a warranty. Preferably, the housing is sealed against unauthorized tampering, for example by the use of a snap ring retainer for a porous lid. The pressure rings are known per se and can not be removed without damage to and therefore sacrifice of the ring.

A fine slanted screw thread is preferred, to allow for more precise adjustment. A preferred maximum inclination is 30 micrometers. These aspects allow the embodiments of the present invention to achieve reductions in CO and HC contaminants that are closer to those that are predicted from the theoretical application of the air purge principle, and significantly better than the spherical bearing design. The present invention, also, independently, provides an appropriate tool for the adjustment of this preferred valve seat. This tool, which according to the third aspect of the present invention comprises an elongated coupling portion extending from a handle, a tip of the coupling portion having a means for interengagement with the valve seat and a longitudinal flow passage which runs internally from the coupling portion from the tip thereof to an outlet displaced from the tip of the elongated portion. Therefore, the tool can be used to couple and rotate the valve seat while still allowing the passage of air through the valve, through the flow passage. Preferably, the passage is narrower in cross-section than the opening of the valve seat to provide a venturi acceleration of the air passing through it. This should provide an audible effect when the air is passing that will be detectable by an engineer tuning the device to help this tuning. Alternatively, or in addition, the outlet of the internal passage may be placed in the vicinity of the handle in order to allow a thumb or other digit to be placed near the outlet to directly detect the flow of air. In a particularly preferred embodiment, the tip of the elongated portion includes a sealing means for sealing against the valve seat. The coupling means may be a simple projection or a pair of projections on the tip of the elongated portion which engage in a corresponding recess (s) in the face of the valve seat, or vice versa. In its fourth independent aspect, the present invention provides an air intake bleed valve for the intake manifold of an internal combustion engine, comprising a valve seat and a valve closure element pushed towards the valve seat, and a flow passage leading from the valve seat to a connection hole for communication with the intake manifold, wherein the cross-sectional area of the flow passage at an intermediate point to the connection port and the valve seat is less than the cross-sectional area of the flow passage, at points both upstream and downstream of that intermediate point. Therefore, the flow passage provides a "venturi" shape. It has been found by the inventor that this arrangement surprisingly provides a much faster transmission than the pressure of the intake manifold to the valve seat and the closure. In this way, the purge valve will react much more quickly than otherwise. In its fifth independent aspect, the present invention relates to an air intake bleed valve for the intake manifold of an internal combustion engine, comprising a valve seat and a valve closure element pushed towards the seat of the engine. valve, wherein the valve closure is conical in external section, the cone angle inclusive being between 55 ° and 125 °, preferably between 75 ° and 105 °, and more preferably between 85 ° and 95 °, and where the seat is correspondingly formed to provide a sealing measure against the closure element. This included angle has been found capable of rapid response of the valve closure element in terms of a transfer distance that is required to open the valve to a sufficient degree, while being narrow enough to minimize any disturbance to the air flow through the closure element. More preferably, the valve closing element remains free floating relative to the valve seat. One way to achieve this is to hold the valve closing element through a pushing means only. By these preferred arrangements, the valve closure element becomes self-centering. This greatly improves the seal when closed, which is of great benefit in this context. Failure to close quickly and properly can cause an increase in fuel consumption, under certain circumstances. In its sixth independent aspect, the present invention provides an air intake bleed valve for the intake fitting of an internal combustion engine, comprising a valve seat and a valve closure element pushed towards the valve seat , where the closure and the seat are made of different plastic material. The plastic material is advantageous under this circumstance because the smaller weight resulting from the closing element reduces the inertia of that element, and in this way increases the reaction speed. A plastic material suitable for one of the elements is nylon 66, and are particularly preferred if the seat is formed of this material. However, the use of identical plastic materials for both the seat and the closure has been found to result in unacceptably high wear regimes. A particularly suitable material for the closure element is a PTFE / acetal mixture. The PTFE component is preferably between 90 and 98 percent, the rest being acetal. A particularly preferred composition is about 96 percent PTFE and about 4 percent acetal. This material is preferred because the PTFE provides a particularly low friction surface that increases the reaction rate, while the acetal ensures that the element has sufficient strength. This low friction surface for the valve provides surprisingly better response times. It is believed that this is because it reduces the tendency of the valve closure to "adhere" temporarily while moving to the closed position. Under extreme circumstances, it is possible for the valve closure to settle in an open position, retained at the site by friction only. This situation can lead to increased fuel consumption. A preferred opening pressure for the valve of all the aforementioned aspects is 356 millimeters of mercury. Clearly, many of the valves encompassed by the above-mentioned aspects will be adjustable with respect to the pressure at which they are opened, in which case, it is preferred that they be capable of adjustment in order to open at that pressure. In the case of relatively large engines, it has been found by the inventor that further improvements in emission reduction can be obtained by providing two of these valves in parallel, with one valve opening at a higher pressure than the other. This means that at higher vacuum levels, larger air volumes can be supplied corresponding to the higher demands of a larger motor. The appropriate pressures are between 330 and 432 millimeters for a valve and up to 406 millimeters for the second, subject to be greater than for the first valve. The present invention also relates to an internal combustion engine comprising an air intake bleed valve communicating with the volume enclosed by the intake manifold, wherein the air intake bleed valve is in accordance with at least one of the aspects mentioned above. It is also related to a vehicle that incorporates this internal combustion engine. The embodiments of the present invention will now be described by way of example, referring to the accompanying Figures, in which: Figure 1 is a partially detailed cross-sectional view of one embodiment of the present invention; Figure 2 is a detailed view of the valve closure element of Figure 1; Figure 3 is a cross-sectional view of a tool in accordance with an aspect of the present invention; Figure 4 is a sectional view of the Figure 3 through lines IV-IV of Figure 3; Figure 5 is a partially detailed cross-sectional view of a further embodiment of the present invention; and Figures 6a and 6b are plan views of the obturator of Figure 5 in open and closed positions, respectively. Referring to Figure 1, this shows a purge valve in accordance with the present invention, together with the dimensional information for the illustrated related parts. It can be seen that the valve comprises a portion 10 of generally cylindrical body having an internal passage 12 extending along the length of the body portion 10. Within passage 12 there is, in sequence, a filter housing 14 at the open end of passage 12 which retains a filter 16 by interspersing it between a flange in the filter housing 14 and a circular retaining clip 18, a portion 20 internally threaded inside. from which a valve seat 22 is retained, a progressively tapered region 24 culminating in an internal flange 26, and a portion 28 that progressively widens at the outlet from which is inserted a sealing element 30 sealing the passage 12. A communication tube 32 is coupled within a threaded bore 34 which opens into the passage 12. In this way, the tube 32 provides an outlet within the pessenger 12. The valve seat 22 has an external screw thread which is engages with the threaded portion 20 of the passage 12. The threaded portion 20 is larger in its longitudinal extension than the height of the valve seat 22 and, therefore, the rotation of the seat 22 of Valve within the screw thread will cause the longitudinal position of the valve seat 22 to be altered.

The inclination of the screw thread is 20 micrometers. A spring 36 remains within the passage 12 and rests at one end in the recess 26 where it is retained in an airtight fit within the tapering portion 24. Spring 36 is 12 millimeters long. At its other end, the spring supports a valve closing element 38, which is shown in greater detail in Figure 2. This has a cylindrical portion 40 that fits snugly within the spring 36, and a cone-shaped portion 42. which fits within the opening of the valve seat 22. In the embodiment shown, the base of the cone 42 is wider than the cylindrical portion 40, but this is not essential. However, it would be necessary to provide a simple edge in which the end of the spring 36 could be bumped to prevent the valve closing element from falling towards the spring. What is necessary is that the cone portion 42 be able to provide a sealing measure against the valve seat 22. On the upper (outer) surface of the valve seat 22 are a pair of recesses (not shown) for coupling with the tool illustrated in Figures 3 and 4. The use and object of this will be described later.

During use, the tube 32 is connected to the intake manifold of an internal combustion engine, and 12 sudden increases in vacuum (decreases in pressure) in the intake manifold above a predetermined amount will be transmitted to the passage 12; will result in the purge valve opening slightly to allow additional purge air. It has been found by the inventor that the progressive narrowing of the passage 12 to a minimum diameter, in this example in the flange 26, provides a venturi effect that accelerates the reaction time of the device. The exact mechanism for this is not yet known, but it is believed that it remains in the creation of a vertex form within the flow passages. The exact pressure at which an individual motor will benefit from the purge air will vary according to the motor, and is generally not predictable in a precise manner. However, this mode can be tuned to a specific motor by rotating the valve seat 22 and thus moving it up or down as illustrated. This will vary both the volume within the passage 12 behind the valve, and the prestressing of the spring 36 when closed. Both of these will vary the reaction characteristics of the valve and will allow it to be tuned to a specific motor. It is preferred if the valve is graduated to open at approximately 356 millimeters of Mercury or more. The valve closure element 38 has an included angle (in this mode) of 115.4 °. This is particularly appropriate for a high performance motor. In a normal family car, an included angle of approximately 90 ° would be more than appropriate.

Essentially, the precise angle is a change between the distance that the valve closing element 38 (and hence the reaction time) must travel and the effect of the obstruction on the air flow rate. The valve seat is of a configuration complementary to the valve closing element, slightly tapered on its outer side to aid air flow. The filter 16 is necessary since the unit will be installed under the hood of the vehicle. An appropriate form of the filter is crushed steel wool, which is a form of filter that can be obtained commercially. Sintered ceramic filters are also possible, but steel wool is preferred due to its lower resistance to air flow. A remarkable advantage of the illustrated arrangement is that the circular staple 18 and the filter 16 prevent unauthorized access to the internal parts of the valve.

In this way, once the valve has been tuned for a specific motor (which of course needs the removal of the filter 16 to access the valve seat 22), the unit can be sealed until its next service, allowing the imposition of a warranty. The materials selected for the different pieces are important. The body 10, the tube 32, the closing element 30, and the filter holder 14 and the circular staple 18 are all structural parts that can be manufactured, for example, from aluminum. This, however, is not particularly vital as long as the parts can be manufactured to the necessary tolerances. In the case of aluminum, an anodized finish is preferred for reasons of corrosion. However, the valve seat 22 and the valve closing element 38 must react very quickly to change the back pressures and be of a material compatible with wear. Therefore, a low density material is preferred for the valve closure element 38 in order to reduce its weight, and this suggests a plastic material. This also involves a plastic material for the valve seat 22, due to wear reasons, but it has been found by the inventor that the use of Nylon 66 for both materials results in a higher wear rate than the preferred one. - 1! In this embodiment, therefore, the valve seat 22 is Nylon 66, while the valve closure element is a commercially obtainable mixture of 94 percent PTFE and 4 percent acetal. This combination is preferred because one material is a polar polymer, while the other is non-polar. Therefore they are incompatible and will not melt at the microscope level. As mentioned above, for large motors it can be beneficial if two of these valves are connected in parallel. An appropriate arrangement is that the output 32 of one valve is connected to the internal space 12 of the other. One valve then graduates to open at a higher pressure than the other, for example, from 230 to 432 millimeters of Mercury for one and 406 millimeters or greater for the second (but in any case, greater than the first). This allows a flow of greater volume of air at particularly high vacuum levels in order to meet the higher demands of a larger motor. Figures 3 and 4 show two cross sections of an appropriate tool for tuning the valve described above. The tool comprises a handle 50 from which extends an elongated portion 52 that is narrow enough to extend into the interior of the passage 12 at its outer end. At the tip of the elongated portion 52 is an O-ring seal 64 and within the O-ring seal are a pair of projections 56a and 56b. Between the positions 56a and 56b is the opening of an internal flow passage 58 communicating with the opening 60 in the joint or union between the handle 50 and the elongated portion 52. During use, the filter 16 and the circular staple 18 are removed, and the tool is inserted into the passage 12. The projections 56a and 56b engage in corresponding recesses on the external surface of the valve seat 22, and the O-ring 54 is sealed against the valve seat 22. At this stage, the engine is running. The operator can rotate the handle 50, which adjusts the vertical position of the valve seat 22 in the manner described above. During this time, all the air collected by the valve will be attracted through passage 58 due to the O-ring 54. Since passage 58 is narrower than passage 12, a "suction" noise will be heard as it travels. open the valve, which will help the operator to tune the valve. Since the outlet 60 is on the edge of the handle 50, an operator can place a finger or other digit near or almost above the opening 60 to provide additional confirmation of air flow.

Figure 5 shows a further embodiment of the invention. In this embodiment, many parts are common with those of the first embodiment shown in Figure 1, and like reference numbers are used to represent like parts. However, there are a number of significant differences that are the following. The thrust spring 36 which pushes the valve closing element 38 towards the valve seat 22 sits on a rim 62 which is movable along the axis of the spring under the control of a servo motor 64. This servo motor is controlled by a programmable controller 66 which is fed with motor operation information, for example, from an engine management system by means of cables 68. In this way, the valve tension is continuously adjustable within limits and this will allow the pressure The vacuum to which the valve opens can be adjusted during engine operation. This allows the unit to be tuned during engine operation to the graduation that corresponds to the type of use. For example, different demands are placed on the engine at idle, urban and travel conditions, and the unit can react to different driving conditions that are detected through the data arriving at the cables 68. The programmable controller 66 It will contain pre-registered graduations that correspond to the different conditions. It has been found that if the rim 62 of the spring moves in order to decrease the tension in the spring 36 at the time the valve is opened, the reduced tension combined with the air flow established through the valve can mean that the valve then does not close properly by itself. Therefore, in this embodiment, a shutter 70 is provided. The shutter 70 is under the control of a servo-shutter 72 which in turn is operated by an interface unit 74. In this embodiment, the obturator 70 is a shutter with three blade blades, and is shown in its open and closed positions in Figures 6a and 6b, respectively. Therefore, immediately before the flange 62 of the spring is moved, the servo-stopper 72 acts to close the shutter 70, which prevents any additional air flow and causes the pressures on either side of the valve to equalize and therefore close the valve. The spring seat 62 is then adjusted to the correct position by its servomotor 64. The plug is then opened and operation is resumed. The shutter 70 and the servo-shutter 72 are positioned in such a way that in case of electrical or electronic failure within the system, the shutter 70 is closed by putting the unit out of action and therefore having no effect on the motor. This "fault-free" action prevents drive failures from affecting the motor in a detrimental manner.With the plug in place, it is clearly impossible to adjust the valve seat 22 using the tool shown in FIGS. 3 and 4. therefore, the approximate adjustment of the valve is only possible during the assembly and allowing the fine adjustment to be carried out through servomotor 64. This acts as an additional means to prevent unauthorized manipulation with the unit by the user who could invalidating a guarantee In a preferred form of the invention, the embodiments of Figure 1 or Figure 5 are combined with a water injection means which acts to inject water into the fuel and air mixture during the acceleration periods, that is, low vacuum This injection of water is known to be beneficial for the operation of the engine during periods of acceleration, and therefore, the combined system will be beneficial During both acceleration and deceleration (during which high vacuum causes the valve to open). It will be appreciated by those skilled in the art that the embodiments described above are only exemplary of the present invention and that many modifications could be made while remaining within the scope of the present invention. For example, the closure element 30 could be formed integrally with the body portion 10, as well as the outlet tube 32 or the filter holder 14. Alternatively, or in addition, a secondary filter could be added before the filter 16 to provide a prefiltration element and prevent the filter seal 16. This could be desirable in countries where there is too much dust. Likewise, the precise dimensions provided are only illustrative and other dimensions could be selected even though the present invention has found that those dimensions shown provide good results. The tests of the illustrated device achieved an 80 percent reduction in CO and even a 70 percent reduction in HC. The device can be manufactured as a discrete unit as illustrated which is suitable for modifying existing vehicles or adjusting during assembly. Likewise, the device can be physically incorporated in the intake manifold as an integral part thereof.

Claims (31)

CLAIMS:

1. An air intake valve for the intake manifold of an internal combustion engine, comprising a valve seat and a valve closure, the seat and the closure have matching conical surfaces formed in complementary fashion, the closure being pushed towards the seat by means of a pushing means acting on the face of the closure placed remote from the seat.

2. An air intake valve according to claim 1, wherein the pushing means is placed to leeward of the valve closure to thereby limit the disturbance of the air flow above the closure.

3. An air intake valve according to claim 1, or claim 2, wherein the pushing means is a compression spring.

4. An air intake valve according to claim 3, wherein the compression spring alone supports the valve closure.

5. An air intake bleed valve for the intake manifold of an internal combustion engine, comprising a valve seat member and a valve closure member pushed toward the valve seat member, the seat member and the closure element being enclosed within a housing, wherein the valve seat member is capable of being positioned within that housing in any of a plurality of longitudinally offset positions with respect to the thrust of the valve closure element.

6. An air inlet bleed valve according to claim 5, wherein the valve seat is longitudinally movable by rotation of a screw thread arrangement.

An air inlet bleed valve according to claim 6, wherein the threads of the screw are external to the seat and internal within a cylindrical bore in the housing.

8. An air intake bleed valve according to any of claims 5 to 7, wherein the seat is disc-shaped.

9. An air intake vent valve according to any of the preceding claims, wherein the housing is sealed against unauthorized tampering.

An air inlet bleed valve according to claim 9, wherein the sealing is by the use of a snap ring retainer for a porous lid.

11. An air intake bleed valve according to any of claims 6 to 8, or 9 to 10, depending on claims 6 to 8, wherein the screw thread has an inclination of 30 micrometers or less.

12. An air intake bleed valve for an intake manifold of an internal combustion engine, which comprises a valve seat and a valve closure element pushed towards the valve seat, where the valve closure is conical in external section, and the inclusion angle of the cone being between 55 ° and 125 °.

13. An air intake bleed valve according to claim 12, wherein the cone inclusion angle is between 70 ° and 100 °.

14. An air intake vent valve according to claim 13, wherein the cone inclusion angle is between 85 ° and 95 °.

15. An air intake bleed valve according to any of claims 12 to 14, wherein the seat has a region of contact with the closure, the region of which is tapered at an essentially corresponding angle.

16. An air intake bleed valve according to any of claims 12 to 15, wherein the valve closing member floats freely with respect to the valve seat.

17. An air inlet bleed valve according to claim 16, wherein a pushing means urges both the valve closure element toward the valve seat as it holds the valve closure element.

18. An air intake bleed valve according to claim 17, wherein the pushing means is a spring.

19. An air inlet bleed valve for an intake manifold of an internal combustion engine, comprising a valve seat and a valve closure element pushed towards a valve seat, wherein the closure and the seat are of a different plastic material.

20. An air intake bleed valve according to claim 19, wherein one of the seat and the closure are nylon 66.

21. An air intake bleed valve according to claim 20, wherein the seat is formed of Nylon 66.

22. An air intake bleed valve according to any of claims 19 to 21, wherein the closure element is a PTFE / acetal mixture.

23. An air intake bleed valve according to claim 22, wherein the mixture comprises between 90 percent and 98 percent PTFE, the rest being acetal and impurities unavoidable.

24. An air intake bleed valve according to claim 23 wherein the PTFE component is essentially equal to 96 percent.

25. An air intake purge valve for a motor manifold essentially as that described herein with reference to the accompanying drawings.

26. An air inlet bleed valve according to any of the preceding claims is adapted to open at an internal pressure of about 356 millimeters Mercury or greater.

27. An air intake arrangement comprising two air intake valves, each being in accordance with any of the preceding claims, each adapted to be connected to the intake manifold of an internal combustion engine, a valve of intake being adapted to open at a first vacuum pressure, the second being adapted to open at a second vacuum pressure, the second vacuum pressure being higher than the first vacuum pressure.

28. An air intake arrangement according to claim 27, wherein the first vacuum pressure is between 330 and 432 millimeters of Mercury and the second vacuum pressure is greater than the largest of Mercury's 406 millimeters and the first vacuum pressure.

29. An air addition arrangement according to claim 27 or claim 28, wherein the outlet of the first or second intake valve is connected to the interior of the second or first intake valve respectively at a point in water below the valve seat and valve closure.

30. An internal combustion engine comprising an air intake bleed valve according to any of claims 1 to 25 or an air intake arrangement according to any of claims 27 to 29, the valve or arrangement being communicates with the volume enclosed by the intake manifold.

31. A vehicle incorporating an internal combustion engine according to claim 30.