INTAKE AIR MODULE OF AN INTERNAL COMBUSTION ENGINE

An embodiment of the invention provides a device for distributing and mixing an intake air for an internal combustion engine, comprising an intake manifold connected with an intake air cooling channel and a bypass channel, wherein the intake manifold is provided with an EGR distribution pipe, wherein the EGR distribution pipe, the intake air cooling channel and the bypass channel are arranged to each other in such a way that a first air flow from the intake air cooling channel and a second air flow from the bypass channel pass around the EGR distribution pipe along the same flow direction.

DETAILED DESCRIPTION OF THE DRAWINGS

Some embodiments may include an automotive system100, as shown inFIGS. 1 and 2, that includes an internal combustion engine (ICE)110having an engine block120defining at least one cylinder125having a piston140coupled to rotate a crankshaft145. A cylinder head130cooperates with the piston140to define a combustion chamber150. A fuel and air mixture (not shown) is disposed in the combustion chamber150and ignited, resulting in hot expanding exhaust gasses causing reciprocal movement of the piston140. The fuel is provided by at least one fuel injector160and the air through at least one intake port210. The fuel is provided at high pressure to the fuel injector160from a fuel rail170in fluid communication with a high pressure fuel pump180that increase the pressure of the fuel received a fuel source190. Each of the cylinders125has at least two valves215, actuated by a camshaft135rotating in time with the crankshaft145. The valves215selectively allow air into the combustion chamber150from the port210and alternately allow exhaust gases to exit through a port220. In some examples, a cam phaser155may selectively vary the timing between the camshaft135and the crankshaft145.

The air may be distributed to the air intake port(s)210through an intake manifold200. An air intake duct205may provide air from the ambient environment to the intake manifold200. In other embodiments, a throttle body330may be provided to regulate the flow of air into the manifold200. In still other embodiments, a forced air system such as a turbocharger230, having a compressor240rotationally coupled to a turbine250, may be provided. Rotation of the compressor240increases the pressure and temperature of the air in the duct205and manifold200. An intercooler260disposed in the duct205may reduce the temperature of the air. The turbine250rotates by receiving exhaust gases from an exhaust manifold225that directs exhaust gases from the exhaust ports220and through a series of vanes prior to expansion through the turbine250. The exhaust gases exit the turbine250and are directed into an exhaust system270. This example shows a variable geometry turbine (VGT)250with a VGT actuator290arranged to move the vanes to alter the flow of the exhaust gases through the turbine250. In other embodiments, the turbocharger230may be fixed geometry and/or include a waste gate.

The exhaust system270may include an exhaust pipe275having one or more exhaust aftertreatment devices280. The aftertreatment devices may be any device configured to change the composition of the exhaust gases. Some examples of aftertreatment devices280include, but are not limited to, catalytic converters (two and three way), oxidation catalysts281, lean NOx traps, hydrocarbon adsorbers, selective catalytic reduction (SCR) systems, particulate filters (DPF)282or a combination of the last two devices, i.e. selective catalytic reduction system comprising a particulate filter (SCRF). Some embodiments include an exhaust gas recirculation (EGR) system300coupled between the exhaust manifold225and the intake manifold200. The EGR system300may include an EGR cooler310to reduce the temperature of the exhaust gases in the EGR system300. An EGR valve320regulates a flow of exhaust gases in the EGR system300. Still other embodiments (FIG. 3) may include a low pressure EGR system (LP-EGR) characterized by a “long route” of the exhaust gases. In this case an additional low pressure EGR valve325will recirculate the exhaust gases downstream the aftertreatment devices towards the compressor240inlet. Moreover, a low pressure EGR-cooler326can be provided.

The automotive system100may further include an electronic control unit (ECU)450in communication with one or more sensors and/or devices associated with the ICE110and equipped with a data carrier460. The ECU450may receive input signals from various sensors configured to generate the signals in proportion to various physical parameters associated with the ICE110. The sensors include, but are not limited to, a mass airflow and temperature sensor340, a manifold pressure and temperature sensor350, a combustion pressure sensor360, coolant and oil temperature and level sensors380, a fuel rail pressure sensor400, a cam position sensor410, a crank position sensor420, exhaust pressure and temperature sensors430, an EGR temperature sensor440, and an accelerator pedal position sensor445. Furthermore, the ECU450may generate output signals to various control devices that are arranged to control the operation of the ICE110, including, but not limited to, the fuel injectors160, the throttle body330, the EGR Valve320, the VGT actuator290, and the cam phaser155. Note, dashed lines are used to indicate communication between the ECU450and the various sensors and devices, but some are omitted for clarity.

Turning now to the ECU450, this apparatus may include a digital central processing unit (CPU) in communication with a memory system and an interface bus. The CPU is configured to execute instructions stored as a program in the memory system, and send and receive signals to/from the interface bus. The memory system may include various storage types including optical storage, magnetic storage, solid state storage, and other non-volatile memory. The interface bus may be configured to send, receive, and modulate analog and/or digital signals to/from the various sensors and control devices. The program may embody the methods disclosed herein, allowing the CPU to carryout out the steps of such methods and control the ICE110.

The present invention is related to a device1, specifically an intake air module comprising an air cooling channel integrated in it. For sake of clarity, before analyzing such device, it will be useful to introduce (with reference toFIGS. 3 and 4) a state of art intake air module11. The architecture comprising an air intake module, with an air cooling channel integrated in it, is realized to reduce the volume of the whole intake system between compressor240and intake valve210, since the intercooler260(as inFIG. 1) can be eliminated. This architecture can be used for both LP-EGR and high pressure EGR (HP-EGR). With this new architecture it is difficult to achieve good mixing of HP-EGR, since it has to be mixed after the intercooler to avoid fouling of the cooler element. This means that the EGR mixing length before the intake valve becomes very short. One solution chosen is to use a EGR distribution pipe50with several holes.

Another feature that is going to be used in modern engines is to incorporate into the air intake module an air bypass channel40, in order to control the temperature of the air into the engine. The combination of all these functions creates a severe issue, since the air flowing into the engine, when a HP-EGR is used, needs to have the same flow direction of the EGR flow, otherwise it is difficult to achieve good mixing of EGR if the air flows through the bypass channel.

InFIG. 3, a scheme of the above architecture is showed. In particular the intake air module11is depicted, comprising an air cooling channel30, comprising a cooler35and a bypass channel41. Such architecture can comprise a different intake manifold20and an air distribution device261for portioning an incoming air flow from the air intake duct205between the intake air cooling channel30and the bypass channel41. Advantageously, the air distribution device can include a first control valve262, controlling the incoming air flow to the intake air cooling channel30and/or a second control valve263, controlling the incoming air flow to the bypass channel41. Alternatively, the air distribution device can include a two-way valve connected with the intake air cooling channel30and the bypass channel40, controlling the incoming air portioning between said channels. All these embodiments contribute to create a fully flexible blend between cold air at the exit of the air cooling channel and hot air at the exit of the bypass channel. Moreover, the engine110uses both a HP-EGR system300, recirculating gas from the exhaust to the intake manifold, and a LP-EGR system325, recirculating gas downstream the aftertreatment system280to the compressor240inlet.

InFIG. 4is shown how a known air and EGR system operates. When all air flows through the air cooling channel (FIG. 4a), in other words the bypass channel is closed, the air routes through the air cooling channel and is mixed with the HP-EGR in the EGR distribution pipe50, located downstream in the intake manifold20. In fact, the air flows along the holes51of the EGR distribution pipe50. This is a preferred solution for HP-EGR mixing when the air cooling channel30is integrated in the intake air module11, due to the short mixing length after the air cooling channel. On the opposite case, in the case the air cooling channel30is fully closed and the bypass channel41is fully open, all air flows through the bypass channel41. Unfortunately, in this case (FIG. 4b) the mixing between HP-EGR and air along the EGR distribution pipe is difficult to achieve: in fact, looking atFIG. 4b, the cylinder located on the right of the picture will receive a lower EGR rate, while the cylinder located on the left of the same picture will get a higher EGR rate. Consequently, no equal EGR mixing is available for all cylinders. In conclusion, the main problem of this architecture is that the HP-EGR distribution pipe50has to comply with two different air paths depending on the fact the air cooling channel30is used or bypassed. This is the technical problem, the present invention aims to solve.

The solution to the mentioned problem, according to the present invention, a new device1, i.e. a new air intake module, is shown inFIG. 5, which shows a front view inFIG. 6, which schematically shows a top view.

The device1for mixing the incoming air comprises an intake manifold20connected with an intake air cooling channel30, comprising a cooler35, and a bypass channel40. The intake manifold20is provided with an EGR distribution pipe50, wherein the EGR distribution pipe50, the intake air cooling channel30and the bypass channel40are arranged to each other in such a way that a first air flow from the intake air cooling channel30and a second air flow from the bypass channel40are passing around the EGR distribution pipe50under the same flow direction. The inventive concept can be appreciated inFIG. 7, which more schematically shows: flux lines of the air coming from the cooling channel500, flux lines of the air coming from the bypass channel510and EGR flux lines520. This makes easier to create a good mixing between air and EGR independent on the fact the air cooling channel30is used or bypassed. In fact, as shown inFIG. 8, with this new solution, when the air cooling channel30is closed and all air flows through the bypass channel40, the air is routed in a similar way as when the air cooling channel30is used (seeFIG. 4a) and exits the bypass channel40in the same direction (i.e. the flux lines of the air coming from the bypass channel510are parallel to flux lines of the air coming from the air cooling channel500and both are parallel to the EGR flux lines520), making it possible to mix EGR within the EGR distribution pipe50.

According to a preferred solution the intake manifold20comprises a plenum21, wherein the EGR distribution pipe50is arranged, and a plurality of air intake runners22connecting such plenum to the intake port of each cylinder of the engine. It is to be understood that the mixing length for air and EGR almost corresponds to the length of the air intake runners22. Therefore, a good mixing between air and EGR is reached along the air intake runners, so providing the same mixing condition for each cylinder of the engine.

Another preferred actuation of the invention provides that the EGR distribution pipe50comprises a plurality of equal spaced holes51, throughout the whole EGR distribution pipe50length, thus further improving the homogeneous mixing between air and EGR due to this symmetrical geometry of the EGR distribution pipe. Alternatively, the EGR distribution pipe50can comprise a plurality of holes51, which are equally spaced in the areas of the intake runners22. With an almost equivalent efficiency, this embodiment provides a good mixing between air and EGR along the air intake runners22, each of them connected with one of the cylinders of the engine.

In the air intake module1a common flow communication between the intake air cooling channel30and the bypass channel40with the air intake duct205is foreseen.

According to a preferred actuation of the invention, the device can comprise an air distribution device261for portioning an incoming air flow from the air intake duct205between the intake air cooling channel30and the bypass channel40. The air distribution device261is part of the intake air module1or at least connected to it. Advantageously, the air distribution device261can include a first control valve262, controlling the intake air flow to the intake air cooling channel30and/or a second control valve263, controlling the intake air flow to the bypass channel40. Alternatively, the air distribution device can include a two-way valve connected with the intake air cooling channel30and the bypass channel40, controlling the intake air portioning between said channels. All these embodiments contribute to create a fully flexible blend between cold air at the exit of the air cooling channel and hot air at the exit of the bypass channel.

Therefore, the geometry of such device enables a robust system when a bypass channel40is used together with the HP-EGR system300and an air cooling channel30is integrated into such intake air module1. This invention allows full flexibility within the described system to blend hot air from the by-pass with cold air from the intercooler and still blend HP-EGR and LP-EGR in any preferred amount of each. All four parameters can be mixed without restriction.