SE1451006A1 - Cleaning device for an air filter unit - Google Patents

Abstract

Summary The present invention relates to a cleaning device for an air filter unit which filters air which is led to an internal combustion engine in a vehicle. The cleaning device comprises a suction line (13) having a first opening (13a) in the air filter unit (6) and a second opening (13b) in an inner cradle surface (3a) of an exhaust line (3) which discharges exhaust gases from the internal combustion engine, and an ejector (14) which is arranged in a position radially inwardly about the outlet opening (13b) of the air line in the exhaust line (3) where it defines a river passage for the exhaust gases between an inlet (14ai) and an outlet (14a2). The cleaning device comprises an ejector (14) having an outlet (14a2) having an adjustable size, an actuator (16) adapted to adjust the size of the outlet (14a2), a sensor (12) sensing a parameter related to the particle content of a area in the air filter unit (6) and a control unit (15) adapted to receive information from said sensor (12) and to activate the actuator (16) so that it adjusts the size of the outlet (14a2) depending on the parameter values received from the sensor ( 12).

Description

BACKGROUND OF THE INVENTION AND PRIOR ART The present invention relates to a cleaning device for an air filter unit according to the preamble of claims 1.

Pipes that carry tuft to an internal combustion engine in a vehicle essentially always include an air filter unit that filters the air before it is led to the internal combustion engine. The air filter unit may comprise a filter container containing a coarse filter which filters the air in a first step and a fine filter which filters the air in a second step. Some types of vehicles are frequently driven in dirty environments. In these vehicles, the air filters quickly become clogged. In order to eliminate particles which accumulate in the air filter unit of such vehicles, it is advisable to provide a suction line between the air filter unit and the exhaust line of the internal combustion engine. The suction line has an opening in the air filter unit and an opening in the exhaust line adjacent to an ejector. With the help of the ejector, a river passage is created with a reduced river area, which results in the exhaust gases obtaining an increased speed and a reduced static pressure in connection with the opening of the suction line in the exhaust line. Thereby a pressure difference is obtained between the openings of the suction line which results in air flow from the air filter unit to the exhaust line. This air flow carries particles that have accumulated in the air filter unit.

US 3,104,962 discloses a cleaning device of the above-mentioned type which, with the aid of an ejector, creates an air flow from a filter unit to an exhaust line via a flexible hose. A disadvantage of applying an ejector in an exhaust line is that it constitutes a flow resistance for the exhaust gases, which results in an increased fuel consumption of the internal combustion engine. This flow resistance of the exhaust gases is obtained whether the vehicle is driven in a dirty environment or a clean 2 JPH09236013 discloses a cleaning device comprising a suction line leading tuft from an air filter unit to a crooked row portion with a nozzle arranged in a central position in an exhaust line. A variable river area for the exhaust gases is provided in connection with the nozzle by means of an adjustable throttling mechanism. Such a crooked rudder portion with a nozzle projecting into the exhaust line creates in itself a flow resistance for the exhaust gases in the exhaust line.

SUMMARY OF THE INVENTION The object of the present invention is to provide a cleaning device which diverts particles from an air filter unit at the same time as it essentially does not create any flow resistance for the exhaust gases in the exhaust line in the case of operation when the vehicle is driven in a clean environment.

The above-mentioned object is achieved with the cleaning device of the kind mentioned in the introduction which is defined in the cantilevered part of claim 1. The cleaning device thus comprises a suction line which has a first opening in an air filter unit and a second opening in an exhaust line. Such a suction line can have a relatively simple construction and it does not require any components projecting into the exhaust line.

The cleaning device comprises an ejector which is arranged in a position radially inside the opening of said suction line in the exhaust line. The ejector has an outlet with an adjustable size. By adjusting the size of the outlet, the speed of the exhaust gases and static pressure in connection with the opening of the suction line in the exhaust line can be regulated. A sensor is arranged in the air filter unit where it senses the value of a parameter which is related to the particle content in an area in the air filter unit. A control unit receives information from the sensor regarding sensing parameter values and initiates activation of an actuator so that the ejector outlet obtains a size depending on the received parameter values.

In the case of operation when the parameter values received indicate a high content of particles in the air filter unit, the outlet of the ejector is given a much smaller size than the inlet of the ejector. This creates a river passage through the ejector at which the exhaust gases obtain an accelerated river velocity and a reduced static pressure. The low static pressure in the exhaust line results in a significantly lower pressure being obtained at the opening of the suction line in the exhaust line than at the opening of the suction line in the air filter unit. The large 3 pressure difference creates a correspondingly large air flow through the suction line. The large air flow through the suction line carries with it particles that have accumulated in the filter unit. This gives the air filter unit an efficient cleaning as the vehicle is driven in a dirty environment. In the case of operation when the parameter values received indicate a low content of particles in the air filter unit, the outlet of the ejector is given a size which essentially corresponds to or the size of the inlet. As a result, the exhaust gases receive essentially no acceleration in the river passage and no reduced static pressure. The pressure difference between the openings of the suction line is of such a size that only a small or no air flow ails is obtained through the suction line. In this case, the river passage through the ejector provides essentially no flow resistance. By means of such a control of the size of the outlet of the ejector, the cleaning device can be activated depending on how many particles have accumulated in the air filter unit. As the number of particles is small, the outlet of the ejector has such a large size that the exhaust gases in the exhaust line only obtain a substantially negligible flow resistance in the river passage. As a result, the flow resistance of the exhaust gases through the ejector can be substantially eliminated during the operating time when the vehicle is driven in a relatively clean environment. Thus, the vehicle's total fuel consumption can be reduced in relation to in a vehicle that has an ejector in the exhaust line with an unregulated river passage. During operating conditions when the vehicle is driven in very dirty environments, the outlet of the ejector can be sized so that a stone air flow is currently obtained through the suction line at an uncontrollable ejector.

According to an embodiment of the present invention, the size of the outlet of the ejector is steplessly adjustable by means of said actuator. Thus, the flow through the overhead line can be regulated with a very good accuracy. Alternatively, the ejector may have a construction so that outlets can only assume certain predetermined sizes.

According to an embodiment of the present invention, the outlet of the ejector has a maximum size which substantially corresponds to the size of the inlet. In the case of operation when the control unit receives information indicating that the particle content in the air filter unit is very small, the outlet of the ejector can obtain the maximum size. In this case, the river passage of the ejector obtains a substantially constant cross-sectional area from the inlet to the outlet. The exhaust flow resistance through the river passage becomes negligible and the presence of the ejector thus does not significantly affect the vehicle's fuel consumption at all. According to an embodiment of the present invention, the ejector is adapted to block the opening of the suction line in the exhaust line when the outlet has the maximum size. Since the opening of the suction line in the exhaust line is coated radially outside the ejector, the ejector can be used to block the opening in the event of an operation as no air needs to be led from the air filter unit to the exhaust line. This also prevents exhaust gases from being led in the wrong direction through the suction line at operating times when the pressure in the exhaust line is higher than in the air filter unit.

According to an embodiment of the present invention, the ejector has an inlet with a size corresponding to the exhaust line cross-sectional area. Thus, the exhaust gases have essentially no flow resistance as they are led into the ejector's river passage via the inlet. The ejector can have an inlet with a constant size.

According to an embodiment of the present invention, the ejector comprises a plurality of movably arranged ejector parts, each of which has a stretch from the inlet to the outlet.

The ejector may comprise a feeder mechanism which strives to move the ejector parts to a laser in which they define the maximum size of the outlet. Alternatively, the ejector parts themselves may have elastic properties so that in an unloaded state they strive to give the outlet the maximum size. With the aid of the actuator, said movably arranged ejector parts can be shifted against the action of said feeder mechanism and assume the law at which they give the outlet adjustable sizes which are smaller than the maximum size.

According to an embodiment of the present invention, said ejector parts have a curved shape so that they form a river passage with a substantially circular cross-sectional area. With a circular river passage, the flow resistance of the exhaust gases can be kept at a low level. Each of said ejector parts may be arranged between two adjacent ejector parts so that the usual ejector part overlaps a first adjacent ejector part at the same time as it in turn overlaps with the second adjacent ejector part.

In this case, the ejector parts are connected to each other so that the actuator only needs to act on one of the ejector parts in order for all ejector parts to be guided by different laws in which they are defined different sizes of the ejector outlet. Said ejector parts can be articulated at a dude adjacent to the inlet. Thus, the opposite free spirits of the ejector parts can define the outlet. Saciana articulated ejector parts can on a simple salt be movably arranged between different layers in which they define outlets of different sizes.

According to an embodiment of the present invention, said sensor is an optical sensor which senses the particle content in said area filter unit. Such a sensor may comprise a light source and a light detector which detects the light intensity from the light source in a suitable area of the air filter unit. Said sensor may alternatively comprise at least one pressure sensor which senses the pressure in an area in the air filter unit. With the aid of such a sensor, the pressure drop across a filter such as a coarse filter or a fine filter in the air filter unit can be estimated. In cases where the pressure drop is large, it is an indication that a large amount of particles have accumulated in the air filter unit and that it is in great need of cleaning.

According to an embodiment of the present invention, the control unit has access to stored information which defines a verb-determined size of the ejector outlet depending on the parameter values received from the sensor. The control unit may comprise stored information which defines an appropriate size of the ejector outlet at substantially all conceivable parameter values which the control unit can receive from said sensor.

According to an embodiment of the present invention, the air line comprises a valve which prevents exhaust gases from being led from the exhaust line to the air filter unit. In particular when the particle content in the air filter unit is low and the ejector outlet has a large size, there is a risk that the pressure in the exhaust line will be greater than in the air filter unit. With the aid of a valve such as, for example, a one-way valve, it is possible in a simple manner to prevent exhaust gases from being led through the suction line to the air filter unit. Alternatively, the suction line may comprise a valve controlled by the control unit. In this case, the control unit can receive information regarding the pressures in the air filter unit and in the exhaust line and with the aid of this information place the valve in a rod where the pressure in the exhaust line is higher than in the air filter unit.

BRIEF DESCRIPTION OF THE DRAWINGS In the following, as an example, an illustrated embodiment of the invention is described with reference to the accompanying drawings, in which: Fig. 1 shows a cleaning device for an air filter unit according to the present invention, Fig. 2 shows the ejector of the cleaning device in Fig. first layer, Fig. 3 shows the ejector of the cleaning device in Fig. 1 in the second layer and Fig. 4 shows the ejector of the cleaning device in Fig. 1 a front view.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION Fig. 1 schematically shows a vehicle 1 driven by an overcharged internal combustion engine 2.

The vehicle 1 is for the most part a heavy vehicle and the internal combustion engine 2 can be a diesel engine or an otto engine. Exhaust gases from the internal combustion engine 2 are discharged via an exhaust line 3. The exhaust gases in the exhaust line 3, which has an overpressure, are led through a turbine 4 of a turbocharger. The turbine 4 thereby receives a driving force which is transmitted via a connection to a compressor 5 of the turbocharger. The compressor 5 thereby compresses air which, via an air filter unit 6, sucks in an inlet line 7. The compressed air in the inlet line 7 is cooled in a charge air cooler 8. A return line 9 is intended to recirculate a part of the exhaust gases from the exhaust line 3. The return line 9 comprises an EGR valve 10 with which the recirculating amount of exhaust gases is regulated. The return line 9 comprises an EGR cooler 11 for cooling the recirculating exhaust gases before they are mixed with the air in the inlet sludge 7 and led to the internal combustion engine 2.

The air filter unit 6 comprises a filter container 6a which encloses a coarse filter 6b and a fine filter 6c. The coarse filter can be made of a cyclone filter and the fine filter can be made of a non-woven filter. A cleaning device for the air filter unit 6 comprises a sensor 12 arranged in a position such that it is capable of sensing a parameter value which is related to the particle content in an area of the air filter unit 6. Sensor may be an optical sensor which optically detects the plurality of particles in a area in the filter unit or a pressure sensor that senses the pressure in an area in the filter unit. The cleaning device further comprises a suction line 13 having a first opening 13a in the filter unit 6 and a second opening 13b in an inner cradle surface 3a of the exhaust line 3. The cleaning device comprises in connection with the suction line opening 13b in the exhaust line 3 an ejector 14 having a river passage with a variable geometry. The suction line 13 comprises a one-way valve 13c which prevents exhaust gases from being led from the exhaust line 3 to the air filter unit 6. The cleaning device also comprises a control unit 15 and an actuator 16. The control unit 15 is adapted to receive information from said sensor 12 and initiate activation of the actuator 16 so that it gives ejektoms 14 river passage and Undamaged geometry. The actuator 16 can be pneumatic, hydraulic or electric.

Figs. 2 and 3 show a sectional view of the ejector 14 in a first layer and a second layer. The ejector 14 comprises a plurality of ejector parts 14a which define a river passage for the exhaust gases inside the exhaust line 3. The river passage has a stretch from an inlet 14ai to an outlet 14a2. Each of the ejector parts 14a has a stretch from the inlet 14ai to the outlet 14a2. The inlet 14ai has a size corresponding to the internal cross-sectional area of the exhaust line 3. Each of the ejector parts 14a has a hinged mount 14a3 adjacent the inlet 14ai. In this case, at least one of the articulated connections comprises a spring member 17 which strives to fit the articulated ejector parts to the first layer shown in Fig. 2. The outlet 14a2 has an adjustable size depending on the action of the actuator 16 on the ejector parts 14a. The actuator 16 has the function of providing a rotation of the ejector parts 14a around the articulated connection 14a3 against the action of the spring means 17. The actuator 16 can, for example, rotate the ejector parts 14a so that they occupy the part shown in Fig. 3.

Fig. 4 shows said ejector parts 14a in a view seen from the front. It can be seen that the ejector parts 14a, which in this case are six in number, have a substantially uniform construction. They have a curved shape that forms part of a circular periphery.

The ejector parts form an armed passage with a substantially circular cross-sectional area between the inlet 14ai and the outlet 14a2. Each of the ejector parts 14a is arranged between two adjacent ejector parts 14a so that each ejector part 14a overlaps an adjacent ejector part on one side at the same time as it is overlapped by the ejector part on the other side. By displacing at least one ejector part 14a with the aid of the actuator 16 the first layer shown in Fig. 2 to the second layer shown in Fig. 3, all ejector parts 14a obtain a rotational movement around their articulated fastenings 14a3.

Thereby the free spirits of the respective ejector parts 14a are pushed towards each other. The actuator 16 is capable of providing a variable displacement movement of said ejector parts 14a so that the free spirits of the ejector parts 14a define an outlet 14a2 with an adjustable size of a stepless salt. The control unit 15 has access to stored information 15a which defines a predetermined size of the ejector 14a2 of the ejector in dependence on the parameter values received from the sensor 12.

During operation of the vehicle 1, the control unit 15 receives substantially continuous infotination from the sensor 12 regarding the particle content of the filter unit 6. When the control unit 12 receives information indicating that the particle content is very low in the filter unit 6, no activation of the actuator 16 is provided. so that they occupy the first layer shown in Fig. 2. In this first Idge, the outlet 14a2 has a maximum size. The outlet has hdr the same size as the inlet 14ai the cross-sectional area of the exhaust line 3. The river passage through the ejector 14 in this case provides a constant cross-sectional area which is substantially the same as the cross-sectional area of the exhaust line 3. In this case, the exhaust gases provide no ejector effect as they pass through the river passage. One of the ejector parts 14a also blocks the opening 13b of the suction line in the exhaust line 3. This prevents exhaust gases from being led into the suction line 13 when the exhaust gases have a higher pressure in the exhaust line 3 than the pressure in the air filter unit 6. In this case the exhaust gases pass through the exhaust line 3 substantially without being affected by the ejector 14.

The control unit 15 receives the parameter value from the sensor 12 which indicates that the particle content is of a value at which the air filter unit 6 should be cleaned, it determines with the aid of the stored information 15a the size that the outlet 14a2 should have at the radiating parameter value. The control unit 12 activates the actuator 16 so that it displaces the ejector parts 14a against the action of the spring means 17 to the point at which the free spirits of the ejector parts form an outlet 14a2 of the size defined by the stored information 15a. The ejector parts 14a can thus occupy the length shown in Fig. 3. In this case the outlet 14a2 has a clearly smaller size than the inlet 14a. The river passage through the ejector in this case provides a successively tapered cross-sectional area. Thus, the exhaust gases provide an accelerated velocity and a reduced static pressure as they leave the outlet 14a2. The static pressure in the exhaust line 3 in connection with the opening 13b of the suction line is in this case lower than the air pressure in the air filter unit 6. This pressure difference creates an air flow through the suction line 13 which carries particles from the air filter unit 6 to the exhaust line 3. The larger particle content in the air filter unit 6 the smaller size is given the ejector outlet 14a2. Thereby an air flow through the suction line 13 is obtained as 51 '- related to the particle content in the air filter unit 6. As a result, an air flow through the suction line 13 of a size which provides an efficient cleaning of the air filter unit can almost always be provided without the exhaust gases having an unnecessarily high flow resistance. the river passage of the ejector. Thus, the fuel consumption of the internal combustion engine can in most cases be reduced in relation to then a conventional ejector with a non-controllable river passage. The invention is in no way limited to the described embodiments but can be varied freely within the scope of the patent claims. The ejector need not be of the type shown in the above-mentioned embodiment, but it may be of another type which makes it possible to regulate the size of the ejector outlet.

Claims (2)

A cleaning device comprises an air filter unit which filters tuft which is led to an internal combustion engine in a vehicle, the cleaning device comprising a suction line (13) having a first opening (13a) in the air filter unit (6) and a second opening (13b) in an internal rocking surface (3a) of an exhaust line (3) discharging exhaust gases from the internal combustion engine, and an ejector (14) arranged in the exhaust line (3) in a position radially inside the air line outlet opening (13b) defining a river passage for the exhaust gases between an inlet (14a) and an outlet (14a2), characterized in that the cleaning device comprises an ejector (14) having an outlet (14a2) with an adjustable size, an actuator (16) adapted to adjust the size of the outlet (14a2), a sensor (12) which senses a parameter related to the particle content in an area of the air filter unit (6) and a control unit (15) which is adapted to receive information from said sensor (12) and to activate a the actuator (16) said that it adjusts the size of the outlet (14a2) depending on the parameter values received from the sensor (12). Cleaning device according to Claim 1, characterized in that the outlet (14a2) is steplessly adjustable by means of the actuator. Cleaning device according to claim 1 or 2, characterized in that the outlet (14a2) has a maximum size which substantially corresponds to the size of the inlet (14a1). Cleaning device according to claim 3, characterized in that the ejector (14) is adapted to block the outlet opening (13b) of the air duct when the outlet (14a2) has the maximum size. A cleaning device according to any one of the preceding claims, characterized by the inlet of the ejector (14a1) having substantially the same size as the internal cross-sectional area of the exhaust line (3). A cleaning device according to any one of the preceding claims, characterized in that the ejector (14) comprises a plurality of movably arranged ejector parts (14a) each having a stretch from the inlet (140 to the outlet (14a2). characterized in that said ejector parts (14a) had a curved shape so that they form a river passage with a substantially cold cross-sectional area 8. Cleaning device according to claim 7, characterized in that each of said ejector parts (14a) is arranged between two adjacent ejector words. that each ejector part (14a) overlaps a first adjacent ejector part at the same time as it in turn overlaps with the second adjacent ejector part 9. Cleaning device according to claim 6 or 8, characterized in that said ejector parts (14a) are hingedly arranged in connection with the inlet (14a1 A cleaning device according to any one of the preceding claims, characterized in that said sensor (12) is an optical sensor which senses on an optical path m particles in an area of the filter unit (6a). Cleaning device according to any one of the preceding claims 1 to 9, characterized in that said sensor (12) is at least one pressure sensor which senses the pressure in an area in the filter unit (6). Cleaning device according to one of the preceding claims, characterized in that the control unit (15) has access to stored information (15a) which defines a predetermined size of the ejector outlet (14a2) in dependence on the received parameter values from the sensor (12). Cleaning device according to one of the preceding claims, characterized in that the suction line (13) comprises a valve (13c) which is adapted to prevent exhaust gases from being led from the exhaust line (3) to the air filter unit (6). innnr 0000 (* 14 9 [. aM4 cic oc eEl. IP 91, 1. 1. 1) 9 q9 9 2. / 3