KR20020032582A - Compressor Inlet System - Google Patents

Abstract

The internal combustion engine of the present invention includes a compressor 23 for supplying a compressed gas for injection of fuel for engine combustion. The intake system 17, 18, 19 includes a throttling assembly 19 for controlling the flow of air through the interior. The gas inlet port of the compressor 23 is connected to the air intake system 17, 18, 19 located downstream of the throttling assembly 19. The present invention lowers the pressure at the inlet port of the compressor 23 below atmospheric pressure. The method for operating an internal combustion engine of this type includes lowering the pressure of the inlet port in the compressor 23 below atmospheric pressure.

Description

Compressor Inlet System

Fuel systems of this kind are known as dual fluid or air assisted fuel injection systems and generally comprise separate fuel metering devices and fuel delivery devices. The fuel delivery device or injection device is generally connected to a source of compressed air, such as an air rail, which is generally arranged to receive compressed gas from the air compressor. Generally, the fuel metered into the injection device is then taken out in gas and highly atomized form and transported directly to the engine's combustion chamber. Such two-fluid injection systems are disclosed in Applicant's US Patent No. RE 36,768 and Applicant's National Patent Application No. WO 99/28621, the contents of which are incorporated herein by reference.

In internal combustion engines of this type, inlets to compressors are used in some applications to remove steam from steam separators or "carbon canisters," which are used to treat the exhaust steam from fuel tanks. Devices of this type are described in the Applicant's US Pat. No. 5,245,974, the contents of which are incorporated herein by reference. In this patent, the inlet portion of the compressor is arranged such that at least a portion of the air introduced by the compressor is sucked through that portion of the steam separator, in which the fuel vapor from a conventional fuel tank and / or fuel system is removed. Accumulate to extract fuel vapors. While this system has been found to be successful, in some applications its performance is limited by the compressor at low engine speeds, especially during idling.

More specifically, the compressor is generally designed to provide a suitable level of compressed air to the fuel injection system over the entire range of the engine. As a result, the compressor generates a maximum volume of air output at the high speed of operation of the engine. Upon idling, the compressor generates a relatively low volume of air output. At such low operating levels, the ability to vent a sufficient volume of air and / or vapor from the carbon caster may be limited and furthermore, It tends to pulsate.

In addition, the possible degassing capacity is related to the required volume of the steam separator. However, it is desirable to provide the separator or canister with the smallest possible size to ensure space in the engine compartment. Furthermore, such a vapor removal device needs to have satisfactory high use durability characteristics.

The present invention relates to an internal combustion engine of the kind that injects a metered amount of fuel for combustion in an engine by supplying air using an air compressor.

1 is a schematic structure of a fuel vapor control and compressed air auxiliary fuel system of the prior art.

2 is a schematic structure of a modification of the steam control and compressed air auxiliary fuel system according to an embodiment of the present invention.

3 is a schematic structure similar to FIG. 2 showing another embodiment of the present invention.

FIG. 4 is a schematic structure similar to FIG. 2 showing another embodiment of the present invention.

FIG. 5 is a more detailed schematic diagram illustrating the steam control and compressed air assisted fuel system partially shown in FIG. 2.

It is an object of the present invention to provide an internal combustion engine having an air compressor for supplying air to provide a more uniform and higher level of suction to the compressor at low speed engines without requiring a change in the design of the compressor. It is to allow the injection.

One aspect of the present invention provides an apparatus for supplying combustion air to an engine including a compressed gas conveying means for supplying compressed gas for injection of engine combustion fuel, and a throttling assembly for controlling the flow of air passing through the engine. An internal combustion engine is provided having a suction system and a gas inlet port of a compressed gas conveying means connected to an air intake system downstream of the throttling assembly to lower the pressure at the inlet port of the compressed gas conveying means below atmospheric pressure. .

Preferably, the compressed gas conveying means is an air compressor which supplies compressed air to inject a metered amount of fuel into the engine. The compressed gas supply means may also be a device operated from the pressure generated in the operation of the internal combustion engine, for example. Some pressure generated in one cylinder during the compression stroke can be used or used directly to drive the compression system. Accumulators may be used for the storage of the compressed gas. In the scavenging of a two-stroke engine, the pressure of the crankcase can be used similarly.

Another aspect of the invention is an engine having an inlet port and comprising a gas compressor arranged to assist injection of engine combustion fuel and a throttling assembly for controlling the flow of air passing therein. Operating an internal combustion engine comprising a suction supply system for supplying and lowering the pressure at the inlet port below atmospheric pressure by connecting the inlet port to the suction system located downstream of the throttling assembly; It provides a driving method.

Preferably, the gas inlet port of the compressor is also connected to a suction system downstream of the throttling assembly, and the flow capacity of the connection on the upstream and downstream sides of the connection is such that It is selected to achieve a preset pressure at the port.

According to one embodiment of the invention, the connections at the upstream and downstream sides of the throttle assembly have a flow capacity determined by the respective opening size selected.

The size of the opening can be chosen to provide an appropriate pressure level at the compressor inlet port for the operating range of the engine. In other words, the flow capacity can be fixed at a selected level for a particular engine compressor system. The upstream and downstream connection is preferably located in close proximity to the throttle element within the throttle body. This can be accomplished by a connection located in the throttle body or in the suction system in close proximity to the throttle body.

In another variation of the invention, it is possible to use a valve located in or in the connection located upstream and / or downstream of the connection so as to control the respective flow capacity. Such valves may be installed to provide variable flow capability, or may simply be on or off. Thus, such a device may provide significant control of the system in some applications where the connections located upstream and downstream in the idling or slow operation of the engine are normally open but the connections located downstream are throttled or closed. In addition, in the high speed operation of the engine, the connecting portion located upstream may be opened or there may be a volume increase. Furthermore, in some applications it may also be desirable to close the connections located downstream in the high speed operation of the engine.

It may be contemplated that the closure or adjustment of the flow capacity of one or both of the connections may be a mechanical device operated in conjunction with a throttle butterfly. In addition, in one possible configuration, a throttle butterfly may be used to physically throttle the connections located upstream.

According to the invention, the pressure reduction at the inlet port of the compressor is preferably on the order of about 3.5 kPa during idling of the engine. This level of pressure reduction can be achieved by a relatively low level of bypass in the throttling assembly as configured by the downstream connection. In addition, since the amount of bypass in the throttling assembly affects the throttle control at engine idling conditions, it is desirable to ensure that the amount of bypass is generally not greater than about 2 kg per hour, but of course depends on engine capability.

The present invention has been primarily developed to provide a suitable source of suction or depressurization for removing fuel vapor from a carbon canister or steam separator containing fuel vapor from a fuel tank and / or fuel system of an internal combustion engine device. However, the constant level of suction required is also applicable where required by engines operating at low speeds. For example, the present invention may also be applied to remove other blow-by-gas that may accumulate in the crankcase of a four-stroke engine, the form of which is the applicant's international patent application. No. WO 99/42711, the contents of which are incorporated herein by reference.

The opening connecting the downstream side of the throttling assembly to the inlet side of the compressor is advantageously sized and positioned so that it can be an opening that plays a major role in generating pressure below atmospheric pressure at the inlet port. In other words, the opening is the main cause of a decrease in the air pressure present at the inlet port of the compressor that can be used to suck fuel vapor from the steam separator. The opening connecting the upstream side of the throttling assembly to the inlet of the compressor is sized and positioned so that it can be a major opening for maintaining a stable air flow of the compressor.

Thus, the vacuum generated at the inlet of the compressor by a connection located downstream of the throttling assembly allows the fuel vapor fixed in the carbon canister to be supplied to the engine by compressed air supplied to the engine injection system. It is used to control the pressure at the inlet. In addition, it is possible to continuously and stably supply the compressed air to the injection system by means of a stable flow of air drawn by the compressor mainly through a connection located upstream of the throttling assembly.

It is clear that the main advantage of the present invention can be achieved by effectively reducing the "basic" pressure at which the compressor operates at least during idling or low speed operation of the engine. In a preferred embodiment of the invention, the system may be designed such that it does not significantly reduce the high speed capability of the compressor, which is important for the correct operation of the fuel injection system.

One embodiment of the present invention will be described by way of example only with reference to the accompanying drawings.

The invention is applicable to all internal combustion engines operating according to the two-cycle or four-cycle principle using a compressor that supplies air to inject combustion fuel into the engine. As noted above, this type of organization is described in the examples of US Patent No. RE 36,768 to Applicant. In engines of this kind, a significant amount of unused fuel may be returned from the fuel injection system to the fuel tank during engine operation. During such recirculation on the basis of conventional engines, the fuel inevitably becomes heated, and consequently may apply more heat to the fuel tank. As a result, the steam generated by the fuel system requires higher removal in the fuel vapor separation system in some applications.

FIG. 1 shows a conventional steam control device using a conventional fuel vapor separator with activated carbon medium 11 and is referred to in the automotive industry as a "carbon canister". In the fuel tank 13, the vapor space 12 is connected to the input side of the separator 10 via a tube 14. The check valve 15 located in the conduit 14 is opened from the fuel tank 13 when the pressure of the fuel vapor in the fuel tank 13 is greater than a predetermined amount, for example, the pressure in the separator greater than 10 kp or more. Allow the flow of steam to the separator (10).

The output side 10 of the separator 10 is located downstream of the conventional air box 18 via the pipe 16 and the throttle through which air is sucked into the intake system of the combustion engine when the engine is running. It is connected to the air intake passage 17 of the engine located upstream of the valve. Therefore, when the engine is in operation and the pressure in the vapor space 12 in the fuel tank 13 is sufficiently high, steam passes from the fuel tank 13 through the separator 10 and in the steam in the separator. The contained fuel is absorbed by the activated carbon and the treated air passes through the air intake passage 17. The air entering the air intake passage 17 from the separator 10 while the engine is running forms part of the air that is delivered to the engine through the air intake system 17.

The tube 20 connects the separator 10 to the tube 21 connected to the ventry tube 22. The duct 21 connects the engine air box 18 to the compressor 23. The ventry tube 22 generates negative pressure as air passes from the air box 18 past the ventry tube 22 and passes through the compressor 23. This reduced pressure is selectively applied to the separator 10 via the tube 20 and past the control valve 24, which may be in the form of a solenoid operated valve provided on the tube 20. The solenoid valve 24 is operated to open and close the tube 20. The valve 24 is an engine control ECU programmed to allow the ECU to properly adjust the metered amount of fuel supplied to the engine when the solenoid valve is opened and air carrying fuel vapor passes through the compressor 23 in the canister. Can be operated by The ECU is also controlled so that fuel vapor can be removed from the separator 10 via the compressor 23.

In normal operation, the compressor 23 sucks air from the air box 18 via the pipe 21 and supplies compressed air to the air rail 26 from which air supplies fuel to the engine combustion chamber. Is supplied to a series of fuel supply injectors 27. A regulator 28 regulates the air pressure in the air rail 26 and the air exiting from the regulator 28 is returned to the tube 21 on the suction side of the compressor 23.

When the solenoid valve 24 is opened at a particular point in the engine operating load range, the low pressure generated at the suction side of the compressor 23 sucks fuel vapor from the compressor 10 through the pipe 20. As a result, this fuel vapor is then supplied to the engine via the feed injector 27. In other words, the air supplied to the injector 27 releases and atomizes a metered amount of fuel and contains fuel vapor. In this way the fuel vapor is removed and introduced into the combustion chamber of the engine. However, as mentioned above, under certain engine operating conditions, the canister vapor removal method is not as effective as desired due to the low level of vacuum present at the inlet side of the compressor 23. In general, this approach can be problematic for low speed operation of the engine and / or engine idling speed.

2 illustrates a variant applied to the apparatus in FIG. 1 according to the invention. Instead of a tube 21 located downstream of the air box 18 and connected to an air intake system 17 adjacent the air box 18, the tube 21 is connected to the T-piece 30. It is connected to the air intake system 17 on one side of the throttle body 33 received within the throttle body or unit 19 via two passages. As shown, the connection to the intake system 17 is disengaged as the throttle body 19 itself, but in practice it may be sufficient for the connection upstream and downstream of the throttle butterfly 33. A damping volume for the purpose of noise vibration reduction is provided in the tube 21 to attenuate other noise and vibration generated in the system.

Positioning the connection 31 on the downstream side of the throttle butterfly 33 allows it to be in a state of being depressurized by the engine suction vacuum via the tube 21 in the compressor inlet. The degree of vacuum is controlled by adjusting the bypass flow ratio through the connection 32 located on the upstream side of the throttle butterfly 33. By appropriately dimensioning the connections 31, 32, the inlet pressure reduction level of the compressor can be set as necessary. This in turn ensures a stable flow of air to the compressor 23 and the injection system while also ensuring the proper flow ratio that can be obtained in the separator 10 during idling. In particular, such a device can be implemented without significant influence on the pressure in the air rail 26 provided by the compressor 23 during normal operation, in particular high speed operation. In addition, control of the engine's idling speed is not affected and does not require any additional hardware to halve the impact of the connections 31, 32. In the embodiment shown in FIG. 3, the control valves 41, 42 are fixed to the connections 31, 32. The throttle position sensor 43 is also provided on the throttle body 19. The valves 41 and 42 and the position sensor 43 are connected to the control ECU of the engine. The ECU is used to control the level of vibration pressure by adjusting the valves 41 and 42 so as to control the flow of the connections 31 and 32 through the connections 31 and 32. This allows the level of vacuum to be optimized according to the speed and / or load of the engine. For example, the upstream connection 32 can be throttled or closed using the valve 42 in engine idling or low speed operation. When the engine is running at high speed, the upstream connection 32 via the valve can be opened or adjusted to impart increased flow. The valve 41 at the connection 31 may be closed at high speed in some applications.

4 shows another variation of the present invention. In this arrangement, a control valve 41 is provided in the connection to the embodiment shown in FIG. 3. Mechanical connection is provided as indicated by arrow 44 between throttle butterfly 33 and control valves 41, 42. The control valves 41 and 42 are adjusted in accordance with the movement of the throttle butterfly 33. Other suitable forms of mechanical linkages can be used to allow adjustment of the valves 41, 42. The mechanical connection is for example closed at high speed operation, corresponding to the butterfly 33 being moved towards the valve 41 in the fully open position and the valve 42 is fully open. Lose. On the contrary, in idling, the linkage device can be installed such that the valve 42 is closed or throttled and the valve 41 is fully open.

As another variation of the invention, only one valve shown in FIGS. 3 and 4 may be employed. The flow through the connection without the valve can be controlled by the opening as described in connection with the embodiment of FIG. 2.

5 shows a more detailed schematic embodiment of the present system. The reference numerals are used in FIG. 5 to refer to the components described in connection with FIGS. 1-4.

In operation, the steam removal system is operated as described in FIG. 1. When the ECU 25 determines that the solenoid valve 24 is open to allow the removal of some fuel vapor from the steam separator 10, the compressor 23 inhales the steam and passes the sucked steam through the air rail ( 26) and to the engine via the feed injector 27.

It is clear that the opening sizes of the connections 31, 32 may need to be adjusted for each particular engine compressor combustion. When testing the present invention on a 1.8L dual overhead cam engine equipped with Applicant's two-fluid fuel injection system, the separator (while still providing sufficiently different pressure across the throttle butterfly to provide adequate control of engine idling speed) 10) it was possible to achieve a fuel steam idle flow rate of about 6 liters per minute. The test was made in an engine having a diameter of 2 mm at the downstream connection 31 and an opening size of 4 mm at the upstream connection. Testing of this system has shown the ability to provide high degassing volumes without loss of compression flow, regardless of any compressor flow fluctuations.

The above description describes only one embodiment of the invention and variations may be made without departing from the scope of the invention.

For example, although the present invention has been primarily described on the basis of automotive applications, it is also applicable to other vehicles and engines, such as motorcycles and scooters, where there is also a need to remove fuel vapors separated by fuel vapor separation means. It is possible.

Claims (23)

A suction gas for supplying combustion air to an engine comprising a compressed gas conveying means for supplying a compressed gas for injection of engine combustion fuel, a throttling assembly for controlling the flow of air passing therein, and a compressed gas An internal combustion engine having a gas inlet port of a compressed gas conveying means connected to an air intake system downstream of the stottle assembly to reduce the pressure below the atmospheric pressure at the inlet port of the conveying means. The method of claim 1, The compressed gas conveying means is an internal combustion engine that supplies compressed air to inject a metered amount of fuel into the engine. The method of claim 2, The gas inlet port of the compressor is also connected to a suction system downstream of the throttling assembly, and the flow capacity of the connection on the upstream and downstream sides of the connection is such that the predetermined pressure at the inlet port of the compressor under the operating conditions of the particular engine. Internal combustion engines selected to achieve this. The method of claim 3, wherein A connection at the upstream and downstream sides of the throttle assembly having a flow capacity determined by the respective opening size selected. The method of claim 2, The connecting portion is in close proximity to the throttling element in the throttling assembly. The method according to claim 4 or 5, The internal combustion engine's flow capacity of the connection downstream of the throttling assembly determines a significant portion of the pressure at the inlet port. The method according to any one of claims 4 to 6, The internal combustion engine's flow capacity of the connection upstream of the throttling assembly determines a significant portion of the stability of the air flow at the inlet port. The method of claim 3, wherein At least one of the connections at the upstream and downstream sides of the throttling assembly includes a valve for controlling each of its flow capabilities. The method of claim 8, Said valve (s) providing variable flow capability. The method of claim 8, The valve (s) is on or off. The method of claim 3, wherein Closure or adjustment of the flow capacity of one or both of the connections at the upstream and downstream sides of the throttling assembly is caused by the movement of the throttle butterfly. The method of claim 11, The throttle butterfly is operated to physically throttle upstream connections. The method according to any one of claims 3 to 12, Internal combustion engine with a bypass amount of throttling assembly not exceeding about 2 kg per hour. The method according to any one of claims 1 to 13, The inlet port is coupled to remove fuel vapor from a vapor separator for receiving fuel vapor from the fuel system. The method of claim 14, The steam separator is a carbon canister and the inlet port of the compressor is also connected to the output side of the canister. Intake supply system for supplying combustion air to an engine having an inlet port and comprising a gas compressor arranged to assist injection of engine combustion fuel and a throttling assembly for controlling the flow of air through the interior Operating an internal combustion engine comprising reducing the pressure at the inlet port below atmospheric pressure by connecting the inlet port to the intake system located downstream of the throttling assembly. The method of claim 16, Connecting the inlet port to the intake system located upstream of the throttling assembly and controlling the flow of air from each connection to provide a selected pressure at the inlet port Driving way. The method of claim 17, And said flow of air is controlled by fixed openings that respectively determine the flow of said connecting portion. The method of claim 17, And said flow of air is controlled by at least one regulating valve that controls the flow of air from each connection. The method of claim 17, Controlling the flow of air from each connection in accordance with the operating speed and / or load of the engine. The method of claim 20, Flow from the connection to the suction system located upstream of the throttling assembly is throttled during low speed operation of the engine. The method of claim 20 or 21, Flow from said connection to said suction system located upstream of said throttling assembly is increased during high speed operation of the engine. The method according to any one of claims 20 to 22, Flow from the connection to the suction system located downstream of the throttling assembly is prevented during high speed operation of the engine.