DE102009015399A1 - Vehicle engine emission managing system, has exhaust passage coupled to another exhaust passage downstream of emission control device, where one of exhaust passages is provided with hydrocarbon retaining system - Google Patents

Abstract

The system has an exhaust passage (35) provided with an emission control device (70), where the passage is provided with a tailpipe of a vehicle. Another exhaust passage (48) is coupled to the exhaust passage (35) downstream of the emission control device, where the exhaust passage (48) is provided with a hydrocarbon retaining system (22). The hydrocarbon retaining system has a vent passage whose portion is positioned adjacent and thermally coupled to a portion of the downstream section of the exhaust passage (35). An independent claim is also included for a method for operating an engine.

Description

The present application claims priority of provisional application 60 / 987,350, filed on 12 November 12, 2007 and hereby incorporated in full becomes.

area

The The present description relates generally to an exhaust gas purification system for one Combustion engine.

Background / Summary

Engine exhaust systems use hydrocarbon retention devices such as hydrocarbon traps around emissions during cold starts for later Withhold reaction or to bring them back into the engine intake system. At a certain Example can be rinsing the exhaust gases are activated when the device is a predetermined Temperature reached.

at However, such examples have several problems for the inventors recognized. So z. B. under some conditions, a long-lasting Desorption of the stored hydrocarbons take place. If So the engine is turned off before the stored hydrocarbons sufficiently rinsed can after that the cold start emissions increase. Furthermore, by a longer one flashing operation other operations such as the adaptive adaptation to different fuels etc. restricted become.

at an approach that can address the above problems is a system for controlling the emissions of the engine of a vehicle provided, the system comprising: a first outlet channel with an exhaust gas purification device, wherein the first channel a downstream Section, the downstream Section after the flue gas cleaning device and a rear exhaust pipe of the vehicle contains; and a second exhaust passage connected to the first exhaust passage is coupled to the exhaust gas purification device, wherein the second Outlet channel contains a hydrocarbon retention system and the Hydrocarbon restraint system contains a venting channel in which at least a portion of the vent passage adjacent to the downstream portion of the vent downstream Section of the first outlet channel positioned and with this thermally coupled.

On this way it is possible taking advantage of the exhaust heat the conditioner the withheld Hydrocarbons to improve the engine intake system. This can Therefore, be particularly advantageous because then, if the exhaust is hot enough is enough Heat on the venting channel to deliver, the exhaust gas purifier also hot enough for the execution a rinsing operation is.

at Another example is the hydrocarbons, if they are not needed, stored to be heated for rinsing.

It It is understood that the summary above in a simplified form presents a selection of concepts that are further explained in the detailed description. It is not intended to indicate key features or material Features of the claimed subject matter, its scope clearly defined by the claims that follow the detailed description is. Furthermore the claimed subject matter is not on the implementations limited, the eliminate any of the disadvantages above or elsewhere of this disclosure.

Brief description of the drawings

1 shows a schematic representation of an engine, an exhaust system and a hydrocarbon (HC) restraint system.

2 shows a schematic representation of an internal combustion engine.

3 . 4 . 5 . 6 and 7 show various embodiments of the HC retention system.

8th . 9 . 10 . 11 . 12 . 13 and 14 are detailed flowcharts illustrating the operation of the engine, the exhaust system and the HC restraint system.

Detailed description

1 is a schematic representation of a vehicle system 6 , The vehicle system 6 contains an engine system 8th that with a hydrocarbon (HC) retention system 22 and a fuel system 18 is coupled.

The engine system 8th can a motor 10 with a plurality of cylinders 30 contain. The motor 10 contains an inlet 23 and an exhaust 25 , The inlet 23 contains a throttle 62 connected to the engine intake manifold 44 via a suction channel 42 is fluid coupled. The exhaust 25 contains an exhaust manifold 48 leading to an exhaust duct 35 leads, which directs the exhaust gas into the atmosphere. The exhaust 25 can be one or more emission control devices 70 included in the exhaust, which may be installed in closed exhaust coupling. One or more Exhaust gas purifiers may include a 3-way catalyst, a lean NOx trap, a diesel particulate filter, an oxidation catalyst, etc. It is understood that other components may be included in the engine, such as various valves and sensors, as for the example engine of 2 is shown.

The exhaust 25 may also be functional with the hydrocarbon retention system 22 over a line 26 and a valve 24 be coupled. In one example, the exhaust gases may become the hydrocarbon containment system during the engine cold-start operation 22 be guided. Once the flue gas cleaning device 70 has reached its operating temperature in the system 22 retained hydrocarbons through the inlet 23 to the engine, as described hereinafter.

Like also out 1 It can be seen, the fuel system 18 a fuel tank 20 included with a fuel pump system 21 is coupled. The fuel pump system 21 can be one or more pumps for pressurizing the to the injection nozzles of the engine 10 , z. B. the injection nozzle shown 66 , supplied fuel. Although only a single injector 66 is shown, further injection nozzles are provided for each cylinder. It is understood that the fuel system 18 a non-return fuel system, a recirculating fuel system, or a fuel system of other types. The fuel system 18 generated vapors can through a pipe 31 to the hydrocarbon retention system 22 (to be described later) before going to the engine inlet 23 be rinsed.

The fuel tank 20 can accommodate a variety of fuel blends, including fuel having a range of alcohol concentrations, such as various gasoline-ethanol blends, including E10, E85, gasoline, etc. as well as combinations thereof.

The hydrocarbon retention system 22 may include one or more hydrocarbon restraints, such as a hydrocarbon trap, configured to temporarily inhibit the hydrocarbons from entering the gases. The hydrocarbon retention system 22 can also have a vent line 27 Contain the gases from the restraint system 22 leads to the atmosphere when hydrocarbons from the exhaust 25 and / or fuel system 18 saved or included. The vent line 27 may also be the intake of fresh air into the hydrocarbon retention system 22 Allow stored hydrocarbons from the exhaust 25 and / or the fuel system 18 via the flushing line 28 and the purge valve 29 to the inlet 23 be rinsed. Although in this example the vent line 27 communicates with unheated fresh air, various modifications can also be used. So z. B. heated intake air can be used from an air filter pot. Furthermore, heated exhaust may be used under selected conditions.

In the system 6 can use different system configurations of the hydrocarbon retention system 22 be provided with various combinations of valves, sensors and the like. For example, various system configurations are described herein with reference to FIGS 3 to 7 explained below. Although the different configurations of the 3 to 7 Various alternative features in certain combinations may represent the different features of the 3 to 7 also be combined with each other to form yet other exemplary configurations. Furthermore, various additional components in the intake, exhaust and fuel system, such as exhaust muffler after the valve 24 be included.

The vehicle system 6 can also have a tax system 14 contain. As shown, the control system receives 14 Information from a plurality of sensors 16 (various examples of which are described herein) and sends control signals to a plurality of actuators 81 (various examples of which are described herein). To give an example, the sensors can 16 an exhaust gas sensor 126 included, which is arranged in front of the exhaust gas purification device, a temperature sensor 128 and a pressure sensor 129 , Other sensors, such as pressure, temperature and composition sensors, may be located at different locations in the vehicle system 6 coupled, which will be discussed in more detail herein.

Another example are actuators that use the fuel injector 66 , the valve 28 , the valve 24 and the throttle 62 include. The tax system 14 can be a controller 12 contain. The controller may receive input data from the various sensors, process the input data, and drive the actuators in response to the processed input data based on programmed instructions or a code corresponding to one or more routines. Exemplary control routines are described herein with reference to FIG 8th to 12 described.

The hydrocarbon retention system 22 can produce hydrocarbons from a variety of sources, including the engine exhaust 25 and the fuel system 18 simultaneously or while uner store different operating conditions. Under some operating conditions, eg. During engine startup, for example, where the exhaust gas purifier has not yet reached its response temperature (eg, a temperature at which the device reaches a selected sufficiently high conversion efficiency for a particular exhaust gas constituent), exhaust from the exhaust 25 to the hydrocarbon retention system 22 and then through the vent line 27 be led into the atmosphere. In this way, larger amounts of cold start hydrocarbon emissions in the hydrocarbon retention system 22 be stored while the exhaust gases are the exhaust gas purifier 70 heat. Once the device 70 has reached a sufficient operating temperature, the exhaust gases are then over the line 35 led into the atmosphere and the hydrocarbon retention system 22 is practically separated from the engine exhaust. Also, those in the fuel tank 20 generated fuel vapors for storage to the hydrocarbon retention system 22 be guided before going to the engine inlet 25 delivered and in the engine 10 to be burned. These different memory types (from the exhaust 25 and the fuel system 18 ) can be performed simultaneously, individually or in combinations.

After separation from the exhaust gas, the hydrocarbon retention system 22 coupled with the engine intake to fresh air through the vent line 27 suck and store the stored hydrocarbons in the engine intake to be burned in the engine. Such a purge operation may occur during selected engine operating conditions as described herein.

Further Details of the flushing and memory operation are described herein.

2 is a schematic diagram showing a cylinder of the multi-cylinder engine 10 represents. As based on 1 the engine can be described 10 at least partially by a control system with the controller 12 as well as inputs from a vehicle driver 132 via an input device 130 to be controlled. In this example, the input device contains 130 an accelerator pedal and a pedal position sensor 134 which generates a proportional pedal position signal PP. The combustion chamber or cylinder 30 of the motor 10 can combustion chamber walls 32 with a piston positioned therein 36 exhibit. The piston 36 can with a crankshaft 40 be coupled, so that the reciprocating motion of the piston is converted into a rotational movement of the crankshaft. The crankshaft 40 may be coupled to at least one drive wheel of a vehicle via an intermediate gear system. Further, a starter motor via a flywheel with the crankshaft 40 be coupled to the starting operation of the engine 10 to enable.

The combustion chamber 30 can intake air from intake manifold 44 over the intake channel 42 get and the combustion gases through the exhaust manifold 48 emit. The intake manifold 44 and the exhaust manifold 48 can be selective with the combustion chamber 30 either via the inlet valve 52 or via the exhaust valve 54 communicate. In some embodiments, the combustion chamber 30 include two or more intake valves and / or two or more exhaust valves. The intake manifold may include a purge passage that is in fluid communication with the exhaust flow, thereby scavenging the engine intake manifold 44 be directed. Although in this example the purge passage is shown after the restrictor to allow the gases to be sucked by the negative pressure in the manifold, various other configurations are possible. So can (z. For example, in the case of a turbocharged engine, the purge line (s) may be routed in front of the turbocharger compressor inlet.

In this example, the inlet valve 52 and the exhaust valve 54 by a cam actuation via corresponding cam actuation systems 51 and 53 to be controlled. The cam actuation systems 51 and 53 may each include one or more cams and one or more cam profile switching (CPS), variable cam timing (VCT), variable valve timing (VVT), and / or variable valve lift (WL) systems included by the controller 12 can be operated to vary the valve function. The position of the inlet valve 52 and the exhaust valve 54 can by means of position sensors 55 respectively. 57 be determined. In alternative embodiments, the inlet valve 52 and / or the exhaust valve 54 be controlled by an electric valve actuation. So z. B. the cylinder 30 optionally including an intake valve controlled via electric valve actuation and an exhaust valve controlled via cam actuation with CPS and / or VCT systems.

The fuel injector 66 is directly coupled with the combustion chamber 30 shown to the fuel proportional to the pulse width of the control 12 via an electronic driver 68 received signal FPW inject directly into this. In this way, the fuel injector provides 66 for the so-called direct injection of the fuel into the combustion chamber 30 , The fuel injector may, for. B. be installed laterally or at the top of the combustion chamber. The fuel may be supplied to the fuel injector via a fuel system (not shown) having a fuel tank, a fuel pump, and a fuel rail 66 be encouraged. In some embodiments, the combustion chamber 30 alternatively or additionally, a fuel injector included in the intake manifold 44 is arranged in a configuration through which a so-called intake manifold injection in front of the combustion chamber 30 provided.

The intake channel 42 can the 62 with a throttle 64 contain. In this particular example, the position of the throttle 64 through the controller 12 be varied by a signal to an electric motor or actuator of the throttle 62 is placed. This configuration is commonly referred to as electronic throttle control (ETC). That way, the throttle can 62 be operated so that they are the intake air to the combustion chamber 30 varies among the other cylinders of the engine. The position of the throttle 64 can the controller 12 be reported via the throttle position signal TP. The intake channel 42 can be an air flow sensor 120 and an intake manifold pressure sensor 122 included the respective signal MAF and MAP to the controller 12 deliver.

An ignition system 88 can in selected modes by means of a spark plug 92 a spark in response to the pre-ignition signal SA from the controller 12 to the combustion chamber 30 deliver. Although spark-ignition components are illustrated, in some embodiments, the combustion chamber 30 or one or more other combustion chambers of the engine 10 operate in auto-ignition mode with or without a spark.

An exhaust gas sensor 126 is with the exhaust duct 48 in front of the emission control device 70 shown coupled. The sensor 126 may be any suitable sensor that provides an exhaust gas / fuel ratio indication, such as a linear oxygen sensor or a UEGO (wide range or wide range oxygen sensor), a dual state oxygen sensor or EGO (exhaust gas oxygen), a HEGO - (heated EGO), a NOx, HC or CO sensor. The exhaust gas purification device 70 is along the outlet channel 48 after the exhaust gas sensor 126 arranged shown. The device 70 may be a three-way catalyst (TWC), NOx trap, any of various other exhaust gas purifiers, or a combination thereof. In some embodiments, the exhaust purification device 70 during operation of the engine 10 periodically reset by operating at least one cylinder of the engine with a certain air / fuel ratio.

The control 12 is in 1 as a microcomputer with a microprocessor unit 102 , Input / output connections 104 , an electronic storage medium for executable programs and calibration values as a read-only memory chip 106 in this particular example, a random access memory 108 , a maintenance store 110 and a data bus. The read-only memory 106 can be programmed with computer-readable data from the processor 102 represent executable instructions for carrying out the methods described below as well as other variants that are contemplated but not specifically listed. The control 12 can different signals from with the engine 10 Receive coupled sensors in addition to the previously discussed signals, including the measurement of the intake air flow rate (MAF), the engine coolant temperature (ECT) from the temperature sensor 112 that with the cooling jacket 114 coupled, a Zündprofil-pick-up signal (PIP) from the Hall sensor 118 (or another type) with the crankshaft 40 coupled, the throttle position (TP) from a throttle position sensor and the absolute intake manifold pressure signal (MAP) from the sensor 122 , The engine speed signal RPM may be from the controller 12 be generated from the signal PIP. The intake manifold pressure signal MAP from an intake manifold pressure sensor may be used to provide an indication of vacuum or pressure in the intake manifold.

As described above shows 2 only one cylinder of a multi-cylinder engine 10 and that each cylinder may analogously have its own set of intake / exhaust valve part, fuel injector, spark plug, etc.

3 shows a first embodiment 300 of the hydrocarbon retention system with hydrocarbon retentions, such as an HC trap 310 parallel to the exhaust pipe 35 after the exhaust gas purification device 70 and a container 322 is arranged. The valve 24 is provided in the exhaust passage for blocking the exhaust gas flow in a first mode and for passing the exhaust gas flow in a second mode. A bypass line 312 is before and after exhaust pipe valve 24 coupled. In addition, the bypass line contains 312 a first bypass valve 314 , an HC trap 310 and a second bypass valve 318 , In this example, the HC trap may be a brick 320 contain. In other examples, the HC trap may contain a plurality of bricks or other structures, e.g. B. activated carbon. Furthermore, the HC trap 310 also be a container in which microporous activated carbon (pore size in the range of 0.5 nm) or zeolites are located. The bypass line 312 leads through the vent line 27 and optionally via the valve 318 and the line 35 to the atmosphere.

The HC trap 310 can over a channel 324 in fluid coupling with a a rinse tank 322 ste hen. The washing container 322 can be configured to collect the vapors from the fuel system, e.g. B. via a line 328 leading to the fuel tank 20 leads. The channel 324 can a valve 326 contain. The washing container 322 can also have a line 330 and a valve 332 in fluid communication with the engine inlet. Similar to the HC trap 310 can the container 322 Activated carbon, albeit with another z. B. larger porosity included.

Although this example shows two hydrocarbon retention devices (eg, the HC trap 310 and the washing container 322 ), various alternatives may be provided. For example, a single hydrocarbon retainer, such as a container, may be used, which container may store hydrocarbons from the exhaust as well as the vapors from the fuel tank. In addition, the two hydrocarbon retarders may each be containers or HC traps, respectively. Regardless of the particular configuration of the HC containment system, the hydrocarbon retarders can take in the cold-start hydrocarbons that are supplied and retain the hydrocarbons.

at an example the hydrocarbon retarders Granular activated carbon contained in a plastic housing, as the exhaust gas temperatures can be significantly lower as the exhaust gas temperatures prevailing in their full range in the exhaust system.

The hydrocarbon retention system 22 from 3 may be operated by a controller by selectively adjusting various valves in a plurality of modes. For example, the following modes are possible:

MODE A: Storage of exhaust gas hydrocarbon

During selected engine and / or vehicle operating conditions, the controller may 12 the valves 24 and 326 close and the valves 314 as well as optional 318 to open. In addition, the valve 332 closed. Exemplary operating conditions include a cold start operation of the engine before the exhaust gas purifier has reached the response temperature. In this mode, exhaust is from the engine 10 through the HC trap 310 led before it over the vent line 27 escapes into the atmosphere while the rinse tank 322 separated from the exhaust gas and the hydrocarbon retention system.

MODE B: Storage of fuel vapors

During selected engine and / or vehicle operating conditions, the controller may 12 the valves 24 and 326 open and the valves 314 and 318 shut down. The valve 332 can be closed, in which case the vapors from the fuel tank are only stored and not rinsed. Alternatively, the valve 332 be opened in a controlled manner, so that some of the vapors are stored from the fuel tank and a part is supplied to the engine for combustion. In this mode, at least a portion of the vapors from the fuel tank are passed through both the purge tank 322 as well as the HC trap 310 passed before passing through the vent line 27 escape. In this case, the fuel tank may communicate with the hydrocarbon containment system.

MODE C: Rinse the HC trap and / or the washing

During selected engine and / or vehicle operating conditions, the controller may 12 the valves 24 and 326 open and the valves 314 and 318 shut down. In addition, the valve can 332 be opened in a controlled manner, allowing fresh air through the vent line 27 for rinsing the HC trap 310 and the rinse container 322 through the valves 330 and 332 to the engine inlet 25 is sucked. In this mode, the purged fuel vapors from the tank and / or the HC trap in the engine are burned while the exhaust gas through the pipe 35 is passed into the atmosphere after the treatment by the exhaust gas purification device.

In an alternative embodiment, the system may additionally or alternatively carry the exhaust gases to the vent line, rather than fresh air via the vent line 27 to purge the stored hydrocarbons so that the heated exhaust gas can heat the hydrocarbon containment system and better purge the stored hydrocarbons. Such an operation may, during certain conditions, e.g. B. low ambient temperatures. Further, under some conditions, the system may purposely purge the exhaust gases during the storage mode to heat the hydrocarbon containment system to a higher temperature, thereby improving the subsequent purge operation. In one example, the exhaust gases may be directed to the hydrocarbon containment system prior to the purge operation (even under no-crank conditions) to increase the temperature and improve the efficiency of the subsequent purge. This operation can be applied if the temperature of the hydrocarbon containment system falls below a threshold or if the possibilities for the Rinsing are restricted.

It should be noted that in the configuration of FIG. that through the HC trap 310 pouring gas to the exhaust 35 be returned and can escape from the rear exhaust pipe. By using the valve 318 (which may be a lower cost, lower temperature valve compared to the other exhaust valves in the system) that allows the exhaust flow to be returned to the exhaust pipe (or to the location of the rear exhaust pipe) provides several advantages. The configuration allows z. For example, during the cold start recovery operation, sufficient flow is provided without passing exhaust gas to locations other than the rear exhaust pipe. Further, by providing a separate channel for the incoming purge air, purge air may be drawn in at a location that is less prone to aspiration of water.

When the exhaust gas is returned to the exhaust system as in 3 In addition, the HC trap may be positioned in front of the exhaust muffler, thereby reducing the effects of exhaust silencer leakage on the performance of the exhaust system.

4 shows a second embodiment 400 of the hydrocarbon retention system 22 , In this configuration, the valve contains 24 a diverter valve that blows the exhaust either through the pipe 35 into the atmosphere or to the direction 412 leads. 4 shows an HC trap 410 parallel to the exhaust pipe 35 after the exhaust gas purification device 70 is arranged. The administration 412 is in front of the valve 24 connected and contains the HC trap 410 ,

Besides, the HC trap can 410 over a canal 424 and a valve 426 in fluid communication with a washing container 422 stand. The washing container 422 can be configured to collect the vapors from the fuel system, such as one to the fuel tank 20 leading line 428 , The washing container 422 can also connect to the engine via a conduit 430 and a valve 432 in fluid coupling. The hydrocarbon retention system 22 can also have a first pressure sensor 436 and one with the line 424 coupled second pressure sensor 438 contain. Furthermore, a temperature sensor 440 be coupled directly to the HC trap for the HC trap.

As in 4 is shown schematically, is the vent line 27 with at least one section of the pipe 35 thermally coupled so that heat is exchanged between them. In one example, the vent line 27 spatially next to at least a section of the pipe 35 are arranged.

The hydrocarbon retention system of 4 may be operated by a controller by the selective adjustment of the various valves in a plurality of modes. For example, the following modes can be executed:

MODE A: Storage of exhaust gas hydrocarbon

During selected engine and / or vehicle operating conditions, the controller may 12 the valve 24 Adjust so that the exhaust gas to the line 413 is diverted, as well as the valves 432 and 426 shut down. Exemplary operating conditions include a cold start operation of the engine before the exhaust gas purifier has reached the response temperature. In this mode, exhaust is from the engine 10 through the HC trap 410 led before it over the vent line 27 escapes into the atmosphere while the rinse tank 422 separated from the exhaust gas and the hydrocarbon retention system.

MODE B: Storage of fuel vapors

During selected engine and / or vehicle operating conditions, the controller may 12 the valve 24 adjust so that the exhaust is routed and the hydrocarbon traps 410 is separated from the exhaust gas. In addition, the controller can control the valve 426 open and the valve 432 shut down. In this mode, at least a portion of the vapors from the fuel tank are passed through both the purge tank 422 as well as the HC trap 410 guided and both in the rinse tank 422 as well as in the HC trap 410 withheld before passing through the vent line 27 escape.

MODE C: Rinse the HC trap and / or the washing

During selected engine and / or vehicle operating conditions, the controller may 12 the valve 24 Adjust so that the exhaust gas through the pipe 34 passed and the hydrocarbon trap 410 is separated from the exhaust gas. In addition, the controller can control the valve 426 open and the valve 432 open controlled, allowing fresh air through the vent line 27 for rinsing the HC trap 410 and the rinse container 422 through the pipe 430 and the valve 432 to the engine inlet 25 is sucked. In this mode, the purged fuel vapors from the tank and / or the HC trap in the engine are burned while the exhaust gas through the pipe 35 is passed into the atmosphere after the treatment by the exhaust gas purification device. In some examples, heat may be by conduction, convection, forced convection, combinations thereof, or alternative forms of heat transfer be transmitted. In this way, when the system is heated to the operating temperature, the heated air can release the HC trap 410 and / or in the washing container 422 support stored hydrocarbons.

5 is a schematic representation of a third embodiment of the hydrocarbon retention system 22 , This embodiment is that of 3 similar, except that the HC trap 510 two bricks 520 is configured and configured so that the exhaust gases pass through the bricks one at a time, but they flush in parallel. In detail, the system of 5 the HC trap 510 parallel to the exhaust pipe 35 after the exhaust gas purification device 70 is arranged. An exhaust pipe valve 24 , the Z. B. may be a throttle is located in the exhaust pipe to block the exhaust gas flow during a first mode and to allow during a second mode. A bypass line 512 is before and after the exhaust pipe valve 24 coupled. In addition, the bypass line contains 512 a first bypass valve 514 , the HC trap 510 and a second bypass valve 518 , The bypass line 512 is also with the vent line 27 via two parallel channels 534 and a valve 538 coupled.

The HC trap 510 also stands over a channel 524 in fluid communication with a washing container 522 , The washing container 522 can be used to collect vapors from the fuel system, about one to the fuel tank 20 (not shown) leading line 528 be configured. The washing container 522 can also have a line 530 and a valve 532 with the motor inlet in fluid coupling.

The hydrocarbon retention system of 5 may be operated by a controller by the selective adjustment of the various valves in a plurality of modes. For example, the following modes can be executed:

MODE A: Storage of exhaust gas hydrocarbon

During selected engine and / or vehicle operating conditions, the controller may 12 the valves 24 and 538 close and the valves 514 and 518 to open. There will also be a valve 532 closed. Exemplary operating conditions include a cold start operation of the engine before the exhaust gas purifier has reached the response temperature. In this mode, exhaust is from the engine 10 through the HC trap 510 passed (successively through the bricks 520a and 520b ) before it over the line 35 27 escapes into the atmosphere while the rinse tank 522 is effectively separated from the exhaust because the flow through a valve 526 Is blocked.

MODE B: Storage of fuel vapors

During selected engine and / or vehicle operating conditions, the controller may 12 the valves 24 . 526 and 538 open and the valves 514 and 518 shut down. The valve 532 can also be closed. The exhaust gases are thus from the container 522 and the HC trap 510 separated. In this mode, at least a portion of the vapors from the fuel tank are passed through both the purge tank 522 as well as the HC trap 510 guided and restrained in both, before going through the valve 538 and the vent line 27 escape. Specifically, the fuel vapors are first passed through the container 522 and then in parallel through the bricks 520a respectively. 520b led before going through 27 escape. In this way, the vapors from the fuel tank can be stored in different concentrations at different points of the traps, as the exhaust gas and the vapors from the fuel tank in different directions, at least from the brick 520a stream.

MODE C: Rinse the HC trap and / or the washing

During selected engine and / or vehicle operating conditions, the controller may 12 the valves 24 and 538 open and the valves 514 and 518 shut down. In addition, the valve can 532 be opened in a controlled manner, allowing fresh air through the vent line 27 for rinsing the HC trap 510 and the rinse container 522 through the pipe 530 and the valve 532 to the engine inlet 25 is sucked. In this mode, the purged fuel vapors from the tank and / or the HC trap in the engine are burned while the exhaust gas through the pipe 35 is passed into the atmosphere after the treatment by the exhaust gas purification device. Here too, the flow direction is opposite to that of MODE B in FIG 5 Fresh air parallel to the bricks 520a and 520b guided before being united and through the rinse tank 522 to be led. In this way, the purging of the vapors takes place in the opposite direction to that in storing the vapors from the fuel tank in both bricks and in the opposite direction when storing the hydrocarbons from the exhaust gas in at least one brick ( 520a ).

These different directions for saving and rinsing, the serial storage as well as the parallel rinse to be able to use enable an improvement in storage and release, whereby the efficiency of the engine and the exhaust system improves becomes.

6 shows more details of an example game of the third embodiment of 5 , Similar components are marked accordingly. In this example, the valves are 24 . 518 and 514 Low-pressure throttle valves. The HC trap contains two bricks 520a , b with activated carbon pellets 612 , A vacuum regulator 614 is with the valves 24 . 514 and 518 coupled and can be configured so that the valve 24 always closes when the valves 518 and 514 are open and vice versa. The vacuum regulator 614 can in an example from the controller 12 be operated electronically.

In addition, according to 6 a first pressure sensor 540 and a second pressure sensor 542 with the inlet 616 and the outlet 618 coupled to the HC trap. A built-in diagnostic sensor 620 (On Board Diagnostic (OBD)) can be between the first and second brick 520a respectively. 520b be coupled. The OBD sensor can measure the gas pressure, the gas composition or a combination thereof in HC trap.

In this example, the HC trap 510 be arranged after an underbody catalyst, but in front of an exhaust muffler. Furthermore, the length of the pipes from the exhaust 35 over 12 inches (about 30.5 cm) to lower the exhaust temperature from 800 ° C to 100 ° C to allow plastic components to be used. In addition, parts made of carbon can be used to reduce the noise in the exhaust when bypassing the exhaust muffler.

In another example, the exhaust flaps at the container inlet and outlet ( 616 . 618 ) made of plastic and be integrated in a plastic housing of the case / the container. The device may include a rubber seal or O-ring to seal around the housing when the door closes, or to lower the plastic door at a lower temperature. The case of the device 510 may include inlet / outlet hoses with 1.5 "ID (3.81 cm ID), integrally formed lugs in the spring section for a sensor and cone valve, molded ports on the air inlet cones and grids on both sides of the carbon bed to allow flow through to allow the container and to allow the exhaust flaps. That with 524 coupled inlet valve can be arranged between the filled beds. At this actuator can the OBD sensor 620 observe the loading and unloading of the beds. In one example, when the plastic exhaust flaps close tightly, the plug valve allows air to enter the air filter pot. The fresh air entering each cone is diverted from the fresh air flow after the vent valve. The escaping air can be used for flushing the fuel tank vapors z. B. one after the other in the container 522 or parallel to it.

7 shows an embodiment of a hydrocarbon retention system 22 , This example is similar to that of 4 although there are other valve and line configurations as well as two HC traps in the bypass 712 be used. Especially in this example, the valve works 24 as a bypass valve to allow the exhaust either through the pipe 35 can flow to atmosphere, or to the exhaust gas flow to the line 714 and to the valve 716 to steer. In this example, the valve is 716 another divert valve, which either connects the line 714 and the line 740 or between the line 714 and the line 742 allows. The bypass 712 also contains a first and a second HC trap 726 respectively. 728 , There is also a valve 726 which directs flow to or from the purge bin (not shown), which then leads to the fuel tank and intake manifold, similar to the configurations described above. This allows the fuel vapors from the fuel tank in this order to the first and second case 726 and 728 be run and rinsed in the reverse order.

In 7 are the two traps 726 and 728 configured with different HC retention properties. The trap 726 can z. For example, activated carbon with greater porosity may contain larger HC molecules than the trap 728 to hold back. In this way, the gases can pass through during storage first 726 and then through 728 be guided, so that the size of the HC molecules in the gas gradually decrease. In addition, since stored HC molecules are difficult to remove from the activated carbon having smaller pores, the activated carbon having smaller pores may be buffered by the activated carbon having larger pores to prevent HC molecules from being irretrievably absorbed in the smaller pores. Incidentally, the adsorption of smaller HC particles in the trap 728 occur at higher pressures. Therefore, the diameter of the inlet pipe from the bypass valve 716 sufficiently dimensioned to the traps to provide the desired pressure during the storage and rinsing operation.

The configuration of 7 looks likewise for both traps 726 and 728 an opposite flow direction for the storage and rinsing operation before. In particular, in the storage of HC in the exhaust gas pass the bypass valves 24 and 716 the exhaust through 714 and then to the trap 726 , then to 728 before it over 27 exit. As the traps rinse, the valves are adjusted to allow fresh air through the vent line 27 , the trap 728 and then the trap 726 to lead before going through 726 is supplied to the inlet. In this way can be an improvement of saving and Release of HC, especially given the different properties (eg porosity) of the traps. The configuration of 7 can thus work in any of modes A, B and C.

While in one example 726 and 728 HC traps can also be used two coal containers. As mentioned, optionally zeolites may be included. The container 726 can z. B. may be configured to absorb cold start propylene and hydrocarbons with greater mass than a separate device. Activated carbon with micropores in 728 absorb smaller hydrocarbons, but can be better protected than those in series 726 , In addition, flushing the traps with preheated air from an air filter pot or with hot vehicle exhaust gases in countercurrent relative to the adsorption flow direction can further enhance performance.

Although this example is in the configuration of 7 represents two traps, more or less traps can be used.

In a particular example, the device may 726 contain a carbon container (with greater porosity) to retain medium to large HC molecules that a container 728 with activated carbon with smaller pores downstream. During storage, the gases pass first 726 and then 728 , The removal takes place in the opposite direction. In this way, the larger pores better protect the smaller pores and reduce the irretrievable adsorption of larger HC molecules in the smaller pores. The adsorption of small HC particles in the small pore medium speaks better to pressure z. B. about 5 Mp (megapond), which can be provided by the appropriate dimensioning of the inner diameter of the inlet conduit from the bypass valve to the containers. Similarly, the removal of the HC particles can be promoted by higher temperatures, such as by a heat transfer from the exhaust gas or by using at least a portion of the exhaust gas z. At idle conditions.

Regarding the 3 to 7 It should be noted that in MODE A HC from the exhaust gas can not only be stored in the hydrocarbon retention system, but also the system can be heated considerably. This can be used to advantage in the hydrocarbon retention system 22 prepare for the subsequent rinsing operation, as a higher temperature causes the stored hydrocarbons to be released more easily.

While further examples of the 3 to 7 show the combined purging of the fuel tank vapors and the stored exhaust hydrocarbons, these may be independently purged in alternative configurations. The HC traps can z. B. flushed via a purge line parallel to a purge line of the exemplary container, thereby enabling a separate and / or independent flushing of the various hydrocarbon storage systems. So z. B. a hydrocarbon retainer can be purged without a second hydrocarbon retainer is purged. Furthermore, in some example configurations, the 3 to 7 the fuel tank vapors in the rinse tanks are purged much faster than the hydrocarbons in the HC traps. In this case, the learned steam quantity / concentration can be used during the first rinsing to determine the amount of fuel vapors stored in the container. During a later portion of the rinse operation (when the container is sufficiently purged / empty), the amount of steam learned / concentration may be used to determine the load level of the HC traps (which occurred during the most recent memory operation, eg, the most recent cold start event). appreciate.

While also the examples of 3 to 7 the non-simultaneous storage of hydrocarbons in the exhaust gas flushing the restraint system 22 In alternative embodiments, a portion of the stored hydrocarbons may be purged while storing other hydrocarbons.

The following method according to 8th to 14 can be implemented using the systems, components, and devices described herein, but optionally also using other suitable systems, components, and devices.

Now be on 8th referenced in which a routine 800 is shown for controlling the engine operation and for monitoring the fuel vapors and the exhaust emission. The routine 800 may be performed during warm-up conditions, such as while the engine or exhaust is being heated from the ambient temperature to the normal operating temperature range.

First, the routine determines in 810 , whether an engine start is present. The routine may, for. B. determine whether the engine is started from standstill. Additionally or alternatively, the routine may determine if the engine has been started by cranking. When there is an engine start, routine is added 812 where it estimates or measures the temperature of the exhaust gas purifier based on various parameters. In one example, the routine may determine the temperature of the exhaust gas purifier based on engine off time (cool down time), ambient temperature, engine coolant temperature, and intake air temperature. Alternatively or additionally, the routine may determine the temperature of the exhaust gas purification device based on one or more exhaust gas temperature sensors in the exhaust duct 35 or in the exhaust manifold 48 determine. In addition, the

routine the temperature of an exhaust gas purification device based on a Determine the temperature sensor attached to the exhaust gas purifier.

In 814 the routine determines a temperature threshold based on the operating conditions. An exemplary approach for determining the temperature threshold is described herein with reference to FIG 9 described. Alternatively, a fixed temperature threshold can be used. In one example, the temperature threshold correlates with the response temperature of the catalyst. The routine then goes up 816 continue to determine whether the storage of hydrocarbons generated in the exhaust gas in the restraint system 22 is activated, and if not, to stop this exhaust. Such an operation may be changed based on various conditions, e.g. B. whether the capacity for hydrocarbon storage of the restraint system 22 is greater than a threshold. The routine may, for. B. the storage in the restraint system 22 allow if the storage system 22 has been purged during the previous engine operation. In addition, the routine can store the hydrocarbons in the containment system 22 allow if the temperature of the restraint system 22 is below a maximum storage temperature. Further, the routine may include storing the exhaust hydrocarbons in the restraint system 22 based on a property of the fuel burned in the engine, e.g. As the alcohol content in the fuel, wherein the alcohol content can be learned during earlier engine operation. In this way, the completion of the guidance of the exhaust gas to the hydrocarbon retention system 22 be changed so that the different storage properties of the different fuels are used advantageously. For example, the guidance may be up to larger amounts of storage or over a longer period of time when fuels of higher alcohol content are burned, as opposed to lower alcohol fuels. Furthermore, the routine may include the storage of hydrocarbons in the containment system 22 when the engine cooling time (eg engine / vehicle OFF duration) is longer than a threshold. In this way, for. B. at hot starts the exhaust gases through the exhaust system 35 be guided and the restraint system 22 bypass.

If the answer is in 816 YES, the routine is on 818 to determine if the temperature of the flue gas cleaning device 70 lower than the one in 814 certain temperature. If this is the case, the routine will start 820 to one or more of the exhaust valves (eg. 24 ) and the exhaust gas through the hydrocarbon retention system 22 and in particular to pass through one or more hydrocarbon traps. Depending on the system configuration, the control system 14 z. B. actuate one or more exhaust valves to the exhaust gas downstream of the exhaust gas purification device 70 to and through the hydrocarbon retention system 22 before it enters the atmosphere or is led. In one example, the routine controls the system in MODE A described hereinabove. The system may also be operated so that the ignition timing is substantially at the time of peak torque or depending on the herein. B. with reference to 10 described operating conditions with a specific spark ignition.

After that, the routine appreciates 822 the amount of hydrocarbon retention system 22 stored hydrocarbon, about the amount of HC trap 310 stored hydrocarbon. The routine may store the amount of hydrocarbon stored based on the exhaust gas flow rate, the exhaust gas temperature, the temperature of the hydrocarbon restraint system 22 , which estimate engine speed and various other parameters.

If the answer is either in 816 NO or in 818 YES, the routine is on 824 to actuate the exhaust valves so that the exhaust gas from the exhaust gas purification device 70 the hydrocarbon retention system 22 bypasses and through the line 35 escapes into the atmosphere. As also discussed herein, the exhaust may be passed through various additional exhaust purifiers and / or exhaust mufflers before it exits to the atmosphere. In one example, the routine controls during step 824 the engine for increasing the exhaust temperature, whereby the ignition timing is sufficiently set after the MBT (minimum advance for best torque) timing later and combustion with a slightly lean air-fuel ratio in the combustion chamber is achieved. step 824 Thus, it may also result in the system not operating in MODE A, although the system is as described herein with reference to FIG 8th is described in more detail, working in the MODES B and C or not.

From 824 or 822 the routine goes on 826 to determine if a rinse of the stored hydrocarbons from the hydrocarbon retention system 22 is to execute (for example, whether the System can work in MODE C). In one example, the routine of FIG 11 For example, determining whether the hydrocarbon retention system 22 to rinse. The cause, the hydrocarbon retention system 22 Rinse may be based on various engine and vehicle operating parameters, including those in the restraint system 22 amount of hydrocarbon stored (eg those in the HC trap 310 stored amount of hydrocarbon), the temperature of the exhaust gas purification device 70 , the temperature of the hydrocarbon restraint system, the fuel temperature, the number of starts since the last rinse, the fuel properties (such as the burned fuel alcohol content) and various others. In one example, the routine determines 826 , whether exhaust gases during the current engine start to the hydrocarbon restraint system 22 are to lead. In a particular example, adjustment is possible so that purging at higher temperatures is caused as the alcohol content in the fuel increases.

If the answer is in 826 YES, the routine is on 828 to operate the exhaust valves so that they receive fresh air through the hydrocarbon retention system 22 and in the inlet channel 42 of the motor 10 suck in what the operation of the system in MODE C can involve. The motor 10 then sucks the vapors together with the injected fuel and the intake air and burns them. After that, the routine appreciates 830 the amount of hydrocarbon from the retention system 22 purged hydrocarbons (in an HC trap and / or in the purge bin) based on various parameters including the amount of stored hydrocarbons, as well as feedback information from the exhaust air / fuel ratio sensors. In one example, the feedback from an exhaust gas / oxygen sensor may be used to learn or update the estimated amount of hydrocarbons stored in the HC trap to determine the state deterioration of the HC trap based on such an estimate. The routine may also adjust the throttling of the engine to control the amount of purge gases drawn through a purge bin, HC trap, or both.

If the answer is in 826 NO is, or after 830 the routine goes on 832 , In 832 the routine determines whether the hydrocarbon vapors generated in the fuel tank are to be flushed if these vapors are in 828 not or not sufficiently rinsed. An exemplary routine for determining if the vapors generated in the fuel tank are to be purged is described herein with reference to FIG 12 be written. If the answer is in 832 YES, the routine is on 834 to the exhaust valves for purging the vapors generated in the fuel tank from the hydrocarbon retention system 22 to operate, which may mean the operation of the system in MODE C. If the answer is in 832 whereas NO is or after 834 , the routine is ended.

Although this in 8th is not specifically shown, the control system may also operate the system in MODE B if it is not operating in MODE A or C. Alternatively, MODE B may be selectively activated based on various operating conditions such as ambient temperature, fuel temperature, and others.

In addition, can by appropriate inclusion of the temperature, the exhaust system to the hydrocarbon retention system and rinsing the Hydrocarbon restraint system to the engine inlet are more accurately controlled to hot start conditions to consider the engine. The system can z. As the temperature of the engine coolant and the catalyst in the activation of the routine and the initiation of rinsing in consider the way that if the coolant temperature is above a Threshold for Hot start and / or the catalyst temperature over a threshold for hot start lies, the exhaust system to Hydrocarbon restraint system is deactivated and rinsing starts as soon as the engine starts / warms up is.

With reference to 9 now becomes a routine 900 for determining a temperature threshold below which the exhaust gases to the hydrocarbon retention system 22 be guided. First, the routine determines in 910 the composition of the fuel. In one example, the routine may determine the alcohol concentration and / or the fuel mixture of the fuel in the tank 20 determine. The alcohol concentration may be learned based on the feedback from the exhaust gas oxygen sensors indicating a shift in the stoichiometric air / fuel ratio. Additionally or alternatively, the routine may determine the alcohol concentration of the fuel based on a fuel concentration sensor. It should be noted that the routine may determine a relative amount of alcohol in a gasoline or in various other fuel compositions.

Thereafter, the routine determines in 912 the fuel temperature. In one example, the routine may adjust the fuel temperature via one with the fuel tank 20 determine the coupled fuel temperature sensor. Alternatively, the routine may estimate the may fuel temperature based on various parameters such as the temperature of the engine coolant, the temperature of the ambient air, and / or various others.

Then the routine determines in 914 one Temperature threshold based on the fuel temperature and the composition or the structure of 912 respectively. 910 , In addition, the routine may set the threshold based on other operating conditions, including aging of the catalyst material of the exhaust gas purifier 70 determine. In one example, the routine may increase the temperature threshold as the amount of alcohol in the fuel mixture increases. In this way, the temperature range can be changed, in which the exhaust gas to a hydrocarbon trap in the hydrocarbon retention system 22 to be led. In such an operation, in particular, the different storage characteristics of the trap can be utilized when the amount of alcohol in the fuel fluctuates. For example, fuels may have different adsorption and / or desorption properties with varying alcohol content. In addition, water in the exhaust may affect the temperature at which storage or release of hydrocarbon particles occurs. With varying alcohol content in the fuel different HC chains can be generated in the exhaust gas, so that different storage / release properties arise. In one particular example, HC may be retained to higher temperatures with an increase in the alcohol content in the fuel so that the cessation or shortening of the MODE A operation is delayed as the alcohol content in the fuel increases until a higher temperature is reached.

Now be on 10 referenced, which is an exemplary routine 1000 to control the combustion air / fuel ratio during engine startup based on the shape of the exhaust routing and / or purging of the hydrocarbon restraint system.

First, the routine determines in 1010 whether the engine is started as for 810 described. If so, the routine is on 1012 to determine if the system is gas to the hydrocarbon retention system 22 directs (eg, whether MODE A is activated). If this is the case, the routine goes on 1014 to select the combustion air / fuel ratio based on the temperature of the engine coolant and various other parameters. After that, the routine works in 1016 at the selected air / fuel ratio with less or no spark retard, such as at MBT spark timing, possibly even during such conditions where the temperature of the exhaust purifier (eg, catalyst in the exhaust) is well below the response temperature. In one example, the in 1014 initially selected to be slightly lean during cranking and approximately stoichiometric or slightly rich after cranking and accelerating to engine speed. Alternatively, the air / fuel ratio may be based on the hydrocarbon retention system 22 stored amount of hydrocarbons (eg amount of in the HC trap 310 stored amount of hydrocarbons) can be selected. If z. For example, the amount of hydrocarbon retention system 22 stored hydrocarbons increases, the combustion air / fuel ratio can be adjusted accordingly higher (eg less fat or leaner).

If the answer is in 1012 NO, the routine is over 1018 to determine if the temperature of the flue gas cleaning device 70 is lower than the response temperature. If the answer is in 1018 NO, if the routine continues to allow combustion in the engine to be at a roughly stoichiometric air / fuel ratio with selective retard ignition (eg, substantially no spark retard, unless required to prevent knocking, torque reduction, etc.). he follows. If, on the other hand, the answer is in 1018 YES, the routine is on 1022 for the combustion to take place in the engine at an approximately stoichiometric or slightly lean air / fuel ratio, the ignition timing being longer than 1016 and or 1020 is delayed. Otherwise, the routine controls in 1020 the engine for combustion at a stoichiometric air / fuel ratio with selective control of the retarded ignition and a shorter delay than in 1022 , The ignition can z. B. be delayed based on the catalyst temperature.

Thus, in another example, the system may operate in a plurality of retarding modes, depending on whether exhaust gases are routed to the hydrocarbon retainer. The modes can z. Example, include a first mode in which the routine performs the exhaust gas to the hydrocarbon retention system, and is performed at least during a part of the first mode with a first ignition timing and a first engine / exhaust air-fuel ratio, and a second Mode in which the routine bypasses the hydrocarbon containment system and at least during a portion of the second mode having a second spark timing later than the first or a second exhaust gas air fuel ratio leaner than the first ratio. In one particular example, the second mode is executed after the first mode during a typical engine start, wherein the first mode is at a lower temperature of the exhaust gas purifier than the second mode. Further, the first air-fuel ratio may be lean during a first part and stoichiometric or rich during a second part of the first mode. Alternatively, the first mode may be executed during a first engine start and the second mode during a second engine start, with the HC during the second start substance retention system stores more hydrocarbons than during the first start.

Thereafter, the routine determines in 1024 in connection to 1020 whether flushing the restraint system 22 including purging the vapors stored in one or both fuel tanks from the stored exhaust gas hydrocarbon (s). If so, the routine is on 1026 where the control system adjusts the fuel injection amount based on the feedback from one or more oxygen sensors in the exhaust gas to maintain the stoichiometric combustion and the amount of hydrocarbons purged from the retention system and / or the amount of the restraint system 22 to learn stored hydrocarbons. In addition, the routine may adjust the position of the throttle responsive to the amount of fresh air drawn by the hydrocarbon containment system. The routine may, for. B. close the throttle when the rinsing operation is initiated to compensate for the additional throughput.

In one example, the engine may provide the desired air / fuel ratio by operating some cylinders at a leaner than the desired air / fuel ratio (eg, stoichiometric) and some cylinders operating at a fatter than the desired air / fuel ratio. Such an approach may be advantageous in that it produces additional exothermic exhaust heat while still maintaining a stoichiometric exhaust air / fuel ratio. In one example, operation with such a split air / fuel ratio may be e.g. During 1016 be provided to allow for greater heating of the exhaust gas purification device. In addition, z. B. by using a HC trap in the restraint system 22 any remaining hydrocarbons resulting from the device 70 be retained, to maintain the desired exhaust gas levels.

Now be on 11 in which a routine is described for determining whether the hydrocarbons generated in the exhaust gas from the restraint system 22 to be rinsed. In one example, the routine of FIG 11 whether to stop the storage of vapors in the fuel tank (eg MODE B) and to proceed to rinse (eg MODE C).

First, the routine determines in 1110 whether an HC retainer such as an HC trap or a container of the system 22 was activated to store the hydrocarbons during engine startup. If so, the routine is on 1112 to determine if the system is flushing the vapors in the fuel tank. If not, the routine will start 1114 to determine whether an exhaust temperature, such as the temperature of the exhaust gas purifier, is higher than a threshold temperature, e.g. B. the threshold of 818 , The threshold can be z. B. adjusted based on the alcohol content of the fuel in the fuel tank and the injected into the engine.

If the answer is in 1114 YES, the routine is on 1116 To determine if the amount of the restraint system 22 stored hydrocarbons (eg the amount of HC trap 310 stored hydrocarbons) is greater than a threshold. If so, the routine is on 118 to determine if the air / fuel ratio of combustion in the engine 10 something is equal to the stoichiometric ratio. If so, the routine is on 1120 to flush the containment system, such as an HC trap and / or a container (eg, operating in MODE C).

In one example, the routine of 11 after the engine starts or during the starting conditions, eg. B. be executed at hot restart conditions.

Now, referring to 12 describe a routine to determine whether the hydrocarbons produced in the fuel tank from the restraint system 22 to rinse. In one example, the routine of FIG 12 whether to stop the storage of vapors in the fuel tank (eg MODE B) and to proceed to rinse (eg MODE C). In one example, the routines of the 11 and 12 coordinated, for example, when the rinsing of the vapors in the fuel tank and the hydrocarbons generated in the exhaust gas takes place simultaneously. In another example, the routines of the 11 and 12 run independently of each other, such as when the purging of the vapors in the fuel tank and the hydrocarbons generated in the exhaust gas is independent.

First, the routine determines in 1210 whether an HC retainer such as an HC trap or a container of the system 22 is rinsed. If so, the routine ends. Otherwise, the routine will start 1212 to determine if engine startup is taking place as described herein. If not, the routine is on 1214 in order to coordinate the purging of the fuel vapors with the adaptive learning of the errors of the fuel injector, the error of the MAF sensor, etc., after which the routine 1216 goes to carry out the rinsing of the fuel tank vapors to the inlet, as in 1214 was coordinated.

If the answer is in 1212 YES, the routine is on 1218 to determine if the combustion air / fuel ratio is about stoichiometric ric air / fuel ratio is (see 10 ). If NO, the routine will inhibit purging, such as when HEGO sensors are used, as it may be difficult to control the air / fuel ratio during a purging operation. If YES, the routine will start 1220 to determine if the system is currently exhausting through the restraint system 22 passes. If so, the routine ends (in the case where purging and saving occur simultaneously). Otherwise, the routine will start 1216 to flush the restraint system to the inlet.

Now, referring to 13 describe a routine for determining whether the exhaust gases are to the hydrocarbon containment system during conditions other than the engine start operation, such as during other engine operating conditions such as a high-speed engine and / or a running vehicle 22 should be led. The routine of 13 Can be used after starting or warming up the engine as described above.

The basis of 13 described operation can z. Example, during conditions in which the cylinder valve of one or more cylinders (eg., Variable Displacement Engine (VDE)) is deactivated and the temperature of an exhaust gas purifier can fall below an activation or response temperature Conditions, the remaining active cylinders can work stoichiometrically or slightly fat and that to the restraint system 22 Exhaust gas passed to store the excess hydrocarbons exits the cooled exhaust gas purification device.

Further, it may be advantageous during a deceleration fuel shut-off (DFSO) or after reactivation of the DFSO cylinders, where a significant amount of fresh oxygen-rich gas is stored in the exhaust gas purifier, thereby reducing the catalytic reaction of the exhaust gases from the exhaust gas Motor and its temperature can be reduced. In reactivating the combustion after a DFSO, where the combustion air / fuel ratio during reactivation is sufficiently rich to reduce the stored oxygen and restore the desired state for oxygen storage of the catalyst, this may be particularly advantageous. The routine of 13 may also be applied during over-temperature conditions of the catalyst (eg, when the catalyst temperature exceeds the maximum allowable temperature for the current conditions) with the engine operating rich to reduce the catalyst temperature.

In one example, the exhaust gas routing routine may be for the hydrocarbon containment system 22 during conditions other than the engine start operation to the hydrocarbon restraint system 22 to heat for the subsequent rinse. So z. B. after sufficient heating of the hydrocarbon retention system 22 the rinsing operation can be activated. This may be beneficial if the hydrocarbon retention system 22 is below a threshold temperature and would otherwise result in too slow and / or insufficient hydrocarbon release and / or desorption.

Now, in detail, on 13 received, according to which the routine in 1310 determines whether engine startup is as described herein. If so, the routine is on 1312 to determine if the hydrocarbon retention system 22 since the engine started the current engine operation has been purged and / or, whether the amount of hydrocarbons and fuel vapors than in the system 22 saved is below a threshold. The routine may, for. B. Determine if the amount of HC trap 310 stored hydrocarbons is less than a threshold.

If this is the case, the routine goes on 1314 to determine if selected conditions exist. In one example, the conditions selected include the potential for hydrocarbon breakthrough from the exhaust gas purifier 70 is higher than a threshold. In another example, the selected conditions include deceleration fuel shutoff of one or more cylinders and / or reactivation upon such conditions. In another example, one of the selected conditions is when the exhaust air-fuel ratio from the engine is enough on the rich side of stoichiometry (eg, richer than a threshold). In another example, one of the selected conditions is that one or more cylinders are disabled, e.g. B. when the inlet and outlet valves are kept closed during the entire 4-stroke cycle. In this case, the routine is approaching 1316 to operate the exhaust valves so that the exhaust gas through the hydrocarbon retention system 22 is guided (eg in MODE A).

In this way, improved exhaust gas purification is achieved even under conditions in which the engine is not started. In addition, it is understood that additional rinsing after the memory operation in FIG 1316 during the subsequent engine operation can be performed after the operation in 1316 is completed.

In a particular example, the routine may be under conditions other than a Engine start-up, wherein the catalyst exhaust gas purifier has a higher than the response temperature, the exhaust gas lead to the hydrocarbon retention system so long, if the temperature of the hydrocarbon restraint system is below a threshold until the hydrocarbon retention system reaches a purge threshold temperature, then the Run exhaust gases into the atmosphere, bypassing the hydrocarbon containment system, and flush the hydrocarbon containment system to the engine intake.

How out 14 can be seen, the control system, the determination of the deterioration of the restraint system 22 activate to B. to determine the differential deterioration between a washing and a HC trap. In some examples, the hydrocarbon purge concentration learned from the feedback of the exhaust gas oxygen sensor and the fuel injection timing may provide independent estimates of hydrocarbon storage, such as when a fuel tank purge bin (eg, a fuel tank purge tank) is used. 422 ) a different temperature than an HC trap (e.g. 310 ) Has. Alternatively, the amount of hydrocarbon learned during purging can be used to determine the performance of an HC trap that has been charged and purged during production of little or no fumes in the fuel tank and before sufficient purging of the vapors in the fuel tank. In another particular example, the HC trap may be diagnosed based on a detected change in gas temperature during purging of the gases by the trap. Various examples as well as additional diagnostic approaches are described hereinafter.

In the following examples, the diagnostic technique will be described with reference to the example of a carbon-based hydrocarbon trap used in the containment system 22 is turned on, described. Further, the operation for the example will be described, in which subsequent to a start event, the exhaust gas flow is diverted through the HC trap until the exhaust gas purification device has been sufficiently heated and has reached the desired conversion efficiency. After storage, the retained hydrocarbons are also purged by passing air through the HC trap back to the engine for combustion. The scavenging flow can take place in series with or parallel to the scavenging of the exhaust vapors generated in the fuel tank in the carbon container. However, the following diagnostic technique may be applied to various other system configurations and modes.

The The following diagnostic technique can be used either as a function or threshold monitor or both are used. The function monitor can determine whether a device is connected and works as expected, while the threshold monitor the effectiveness of the exhaust gas purification device can determine.

One potential Deterioration mode can cause vibration damage and mechanical damage of the Carbon in the HC trap include -. B. can the carbon granules decay and be used up. Thus, the HC retention of the Trap be reduced when the carbon granules decay and possibly lost through the rear exhaust pipe. If enough carbon is lost or compressed and the volume of the Trap not filled is a part of the exhaust gas can bypass the carbon bed and the Exhaust gases from the rear exhaust pipe may increase. In one approach Therefore, a monitor is used as a threshold monitor, the detects the loss of carbon volume.

at In a first approach, the control system can control the temperature at the outlet the HC trap during of restraint and rinsing measure up. After a cold start is expected that the temperature at the outlet with increasing warming of the exhaust system increases. This indicates that the system is connected to the exhaust system and to divert the flow to Trap valves work properly. After that the flow bypassed the trap, the temperature should stabilize, what a proper cycle close the valves. One further increase in temperature would mean that the trap still exhaust gas is supplied. While of the rinse cycle The temperature should drop as fresh air enters the trap.

at In a second approach, the pressure difference across the carbon bed of the HC trap during the retention or the conditioner as an indication of a flow restriction be measured by the carbon. A loss of carbon would be too a reduction in pressure differential for a given throughput to lead. One or more pressure sensors can be installed before and / or after the HC trap.

In a third approach, a fuel vapor / hydrocarbon sensor may be used. So z. For example, a HC sensor in the trap leak directly measures the effectiveness of the trap during containment because any degradation in the trap will result in an increase in HC breakthrough at the vent line 27 would result. To improve the effectiveness of the threshold monitor, modeling of exhaust gas concentration and composition as a function of engine speed / load / spark retard temperature / and / or engine temperature may be provided total fuel consumption since start, along with the expected reduction in HC before the trap due to the response of the catalyst. Alternatively, an empirical model of the expected out-of-trap HC could be used.

at a fourth approach Temperature sensors located before and after the HC trap, an indication of the temperature difference during the retention (eg by adsorption) and rinse (z. B. desorption) provide phases. The temperature difference can also by the percentage flow rate of the carbon bed (mainly water and HC) adsorbed or desorbed. at other examples may include temperature variations of expected or estimated Values are used. In the examples, an HC trap in the Exhaust system with a downstream arranged to use temperature sensor, the system can be a derivative Exhaust gas temperature at the trap outlet vorse hen to a temperature difference between the derived and the actual temperature at the trap outlet to create. The system can then base the adsorption function on diagnose this temperature difference. Furthermore, due to potential Error in the temperature estimates the identification of a temperature shift based on the temperature sensor detected initial temperature and then the measured temperature rise compared to the estimated Temperature increase during selected conditions like saving or rinsing respectively. Furthermore Note that in some examples, the exhaust air / fuel ratio sensors under selected Conditions can work as a temperature sensor.

at a fifth Approach, a position measurement of the HC trap can be performed. Especially to prevent vibrations in the carbon the trap and / or container to damage, can the facilities have a floating end plate and one or more Contain springs to keep the carbon constant with a certain pressure to act on. If the carbon despite these measures damaged can, the volume reduction to a position change the end plate (s) and a lower spring force lead. Around Identifying the carbon loss can be done in different ways be used for motion detection. For an example u. a. a position sensor, a thinner Wire that snaps at a strain of the spring, contacts that are at open a movement of the plate, Transducer for measuring the spring force or strain gauge in be included in the spring built-in facilities.

at a sixth approach Probes showing the conductivity of the carbon bed, used to obtain an impedance reading to be provided when a decrease in the spring force or a Reducing the carbon volume would increase. The resistance between two contact surfaces, which is on the top of the container attached, can be stronger increase when the bed is sufficiently compacted for the fumes to form a bypass path. In one example, the conductivity while selected Conditions are measured, for. B. during or after warming up.

It It should be noted that the exemplary tax and estimation routines for different ones Engine and / or vehicle system configurations can be used. The Specific routines described herein may include one or more processing strategies represent a variety, which are event-driven, interrupt-driven, Multi-program, concurrency-controlled and the like can act. With that you can various of the presented measures, operations or functions in the sequence shown, in parallel or in some cases even not executed become. The specified order of processing is also Not essential to the features and benefits of the herein described embodiments but to better understand the presentation and the Description. One or more of the measures shown or functions can be executed repeatedly depending on the applied strategy. Furthermore you can the measures described to be programmed into the readable storage medium in the engine control system Graph the code.

It It should be understood that the configurations and routines disclosed herein by way of example and not to be construed in a limiting sense, because numerous variations possible are. For example, the above technology can be applied to V6, I4, I6, V12, four-cylinder boxer and other engine types are applied. The subject matter of the present disclosure includes all novel and not obvious combinations and subcombinations of the different ones Systems and configurations as well as other features disclosed herein Functions and / or properties.

In particular, the following claims specify certain combinations and sub-combinations that are believed to be novel and not obvious. These claims may refer to "a" or "a first" element or its equivalent. Such claims are to be understood to include one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and subcombinations of the disclosed art Features, elements and / or properties may be claimed by amending the present claims or by presenting new claims for this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, are also to be considered as covered by the subject matter of the present disclosure.

Claims (15)

System for controlling the exhaust gases of an engine of a Vehicle, the system comprising: a first outlet channel, which contains an exhaust gas purification device, wherein the first channel a downstream Section after the flue gas cleaning device and a rear exhaust pipe of the vehicle contains; one second with the first exhaust passage after the exhaust gas purification device coupled outlet channel, wherein the second outlet channel is a hydrocarbon retention system contains the hydrocarbon retention system includes a vent channel, wherein at least one section of the ventilation duct next to at least a section of the downstream Section of the first outlet channel and arranged with this thermal is coupled. The system of claim 1, further comprising a flushing channel, coupled between an engine intake and the hydrocarbon restraint system is. The system of claim 2, further comprising a control system configured to exhaust the exhaust gases during a first state leads to the second exhaust passage to the exhaust gas hydrocarbon in the hydrocarbon retention system to save, and while a second state, the hydrocarbon retention system to the engine intake to wash. The system of claim 3, wherein the control system while of rinsing the hydrocarbon retention system operates so that fresh air is sucked into the vent channel, to the hydrocarbons from the hydrocarbon retention system to flush to the engine inlet. The system of claim 4, wherein the control system the beginning of the flushing in response to the exhaust gas temperature. The system of claim 1, further comprising a plurality Valves to the exhaust gas selectively to the first and second channel respectively. The system of claim 1, further comprising an exhaust muffler in first channel has. Method for operating an engine with a hydrocarbon restraint system, which is coupled to an engine exhaust and an engine intake, the method comprising: during an engine start guiding the Exhaust gas to the hydrocarbon retention system and discharging the exhaust gases into the environment via a vent passage; Lead the Exhaust gases into the atmosphere and bypassing the hydrocarbon restraint system, when the temperature of a catalytic coupled with the exhaust Exhaust gas purification device reaches a threshold temperature; Rinse the Hydrocarbon retention system with Fresh air over the venting channel to the engine inlet; and heat transfer from the exhaust gas to the exhaust gas purification device to the fresh air in Venting channel, without the exiting the exhaust gas purification device exhaust gas with the Fresh air in the venting channel too Mix. The method of claim 8, wherein the rinsing on Based on the alcohol content of the fuel burned in the engine. The method of claim 8, further comprising the operation with an ignition timing at MBT spark timing while of the engine starts, even if the temperature of the catalytic Exhaust gas purification device well below the response temperature lies. The method of claim 8, wherein the threshold in response to the alcohol content of the fuel burned in the engine is set. The method of claim 8, further comprising the determination the deterioration of the hydrocarbon restraint system as a reaction on the air / fuel ratio in the exhaust during of rinsing having. The method of claim 8, further comprising guiding the fumes Having in the fuel system to the hydrocarbon retainer. A method of operating an engine having a hydrocarbon containment system coupled to an engine exhaust and an engine intake, the method comprising: during an engine start, directing the exhaust to the hydrocarbon containment system and exhausting the exhaust into the environment via a vent passage, and guiding the engine Exhaust gases into the atmosphere and bypassing the hydrocarbon retention system when the temperature of a catalytic exhaust coupled to the exhaust purification device reaches a threshold temperature; during conditions other than engine startup where the exhaust gas purifier exceeds the response temperature, directing the exhaust to the hydrocarbon restraint system when the temperature of the hydrocarbon restraint system is below a threshold, continuing the routine until the hydrocarbon restraint system thresholds Rinsing temperature, and then leading the exhaust gases bypassing the hydrocarbon restraint system to the atmosphere and purging the hydrocarbon retention system with fresh air to the engine intake. The method of claim 13, wherein the hydrocarbon retention system a plurality of hydrocarbon retention devices with always smaller pores in the direction of the exhaust gas flow during the storage operation contains.