DE112017003919T5 - Method and device for engine control - Google Patents

Abstract

The present disclosure relates to an engine control unit (7) for controlling an internal combustion engine (2) for regenerating a particulate filter (6) disposed in an exhaust system (3). The engine control unit (7) has at least one processor (8) configured to receive a first signal (SIG1) from a first oxygen sensor (10) for determining an oxygen content of an exhaust gas in the exhaust system (3) downstream of the particulate filter (6) receive. A memory device (9) having instructions stored therein is coupled to the at least one processor (8). The at least one processor (8) is configured to control the lambda (λ) of the internal combustion engine (2) in response to the first signal (SIG1). The engine control unit (7) finds particular application in the control of a gasoline engine. The present disclosure also relates to a vehicle (1) having an engine control unit (7) for controlling the internal combustion engine (2) and a method for controlling an internal combustion engine (2).

Description

TECHNICAL AREA

The present disclosure relates to the method and apparatus for engine control. More particularly, but not exclusively, the present disclosure relates to an engine control unit, a vehicle, and a method of controlling an internal combustion engine. The engine control unit is used in particular in gasoline engines.

BACKGROUND

A vehicle having an internal combustion engine typically includes aftertreatment systems for treating exhaust gases discharged during a combustion cycle of the internal combustion engine. The aftertreatment systems are provided in an exhaust system for carrying exhaust gases from the internal combustion engine. It is known that one or more catalysts, such as a Three-Way Catalyst (TWC), are provided to reduce carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxides (NOx). The exhaust system of a gasoline engine may include, for example, a starter catalyst and a main catalyst. The aftertreatment system may also include a particulate filter. The particulate filter traps carbonaceous particulate matter to prevent it from being released into the atmosphere with the exhaust gas. The particulate filter is regenerated by oxidation of the carbonaceous particulate material. The oxidation is carried out at high temperatures with oxygen. Oxidation can occur at temperatures above 400 ° C, but the rate increases exponentially with temperature. For example, the oxidation rate in the temperature range of 400 ° C to 500 ° C may be relatively low (although it may prove useful for the passive regeneration of the particulate filter). At temperatures above 500 ° C, the oxidation rate is higher and the regeneration of the particulate filter can be performed to oxidize accumulated carbonaceous particulate material. For gasoline particulate filters, the oxidation temperature for a coated gasoline particulate filter is preferably higher than 600 ° C, and for an uncoated gasoline particulate filter, preferably higher than 650 ° C.

In diesel particulate filters, excess oxygen is available for oxidation of the carbonaceous particulate matter in the particulate filter. However, the exhaust gas temperature may not be sufficient under normal use, and regeneration strategies may be needed to increase the temperature of the diesel particulate filter to perform active regeneration. In the case of a gasoline particulate filter (GPF), the exhaust gas has a higher temperature and regularly exceeds the threshold of 500 ° C. required for the oxidation of the carbonaceous particulate material. It should be noted that the operating conditions of the GPF are dependent on its location relative to the internal combustion engine, for example the lower the operating temperature, the greater the distance between the engine and the GPF. In normal operation, the gasoline engine operates under stoichiometric conditions and there is a small amount of oxygen in the exhaust gas used to oxidize carbon monoxide (CO) and unburned hydrocarbons (UHC) in the catalyst. However, no oxygen is available in the exhaust gas for the oxidation of the carbonaceous particulate material in the GPF. The most important source of oxygen for the oxidation of the carbonaceous particulate material in the GPF in normal operation is the fuel cut through fuel cut, but not during customer operating cycles where there is not sufficient deceleration and / or fuel cut. In addition, control modes such as "coasting" and "sailing" may be implemented, which may reduce the number of slowdown events suitable for particulate filter regeneration. The frequency with which appropriate slowdown events may occur in mild hybrid electric vehicles (MHEVs) and plug-in hybrids (PHEVs) may also be less.

Typical gasoline systems place a heated exhaust gas oxygen sensor (HEGO) behind the starter catalyst and upstream of the main catalyst. The GPF is typically placed in the main catalyst position (eg, a coated GPF replacing TWC) or further back in the exhaust system (eg, an additional uncoated GPF). However, the engine control unit is configured to control the fueling of the gasoline engine to maintain lambda (λ) at least substantially one (1) based on an equilibrium of gaseous exhaust emissions reacting in the TWC. This limits the amount of oxygen available for oxidation of the carbonaceous particulate material in the GPF during closed loop operation.

In at least certain embodiments, the present invention aims to provide a control apparatus and method that overcomes or ameliorates at least some of the limitations of prior art systems.

SUMMARY OF THE INVENTION

Aspects of the present invention relate to an engine control unit, a vehicle, and a method of controlling an internal combustion engine, as claimed in the appended claims.

• zumindest einen Prozessor, der konfiguriert ist, um ein erstes Signal von einem ersten Sauerstoffsensor zum Bestimmen eines Sauerstoffgehalts eines Abgases im Abgassystem stromabwärts des Partikelfilters zu empfangen und um ein zweites Signal von einem zweiten Sauerstoffsensor zu empfangen, der im Abgassystem stromaufwärts des Partikelfilters angeordnet ist, wobei der zumindest eine Prozessor konfiguriert ist, um das erste und zweite Signal zu vergleichen, um eine Erhöhung oder eine Verringerung des Sauerstoffgehalts des Abgases im Abgassystem stromabwärts des Partikelfilters zu erfassen; und
• eine Speichervorrichtung mit darin gespeicherten Befehlen, die mit dem zumindest einen Prozessor gekoppelt ist;
• wobei der zumindest eine Prozessor konfiguriert ist, um das Lambda (λ) des Verbrennungsmotors in Abhängigkeit von einer Erhöhung oder einer Verringerung des Sauerstoffgehalts des Abgases im Abgassystem stromabwärts des Partikelfilters zu steuern. Das Abgassystem ist mit dem Verbrennungsmotor verbunden. Im Einsatz wird das Abgas des Verbrennungsmotors durch das Abgassystem geleitet und durchströmt den Partikelfilter. Der Partikelfilter fängt kohlenstoffhaltiges Partikelmaterial im Abgas ab. Um den Partikelfilter zu regenerieren, wird das eingeschlossene kohlenstoffhaltige Partikelmaterial oxidiert und dieser Prozess verbraucht Sauerstoff. Durch Überwachen des Sauerstoffgehalts des Abgases stromabwärts des Partikelfilters kann die Motorsteuereinheit bestimmen, dass im Partikelfilter eine Oxidation stattfindet. Die Motorsteuereinheit kann möglicherweise eine Rate bestimmen, mit der die Oxidation im Partikelfilter stattfindet, um beispielsweise zu bestimmen, dass die Oxidation bei oder über einer vorbestimmten Schwellenrate stattfindet. Der zumindest eine Prozessor ist konfiguriert, um den Verbrennungsmotor in Abhängigkeit von einer Erhöhung oder Verringerung des Sauerstoffgehalts des Abgases im Abgassystem stromabwärts des Partikelfilters zu steuern. Die Motorsteuereinheit kann den Betrieb des Verbrennungsmotors steuern, um den Partikelfilter zu regenerieren. Insbesondere kann die Motorsteuereinheit den Betrieb des Verbrennungsmotors so steuern, dass die Abgase Sauerstoff enthalten, um kohlenstoffhaltiges Partikelmaterial im Partikelfilter zu oxidieren. Zumindest in bestimmten Ausführungsformen ist die Motorsteuereinheit betreibbar, um den Motor zu steuern, um die Regeneration des Partikelfilters zu fördern, wenn die vorherrschenden Bedingungen im Partikelfilter für die Oxidation von eingeschlossenem kohlenstoffhaltigen Partikelmaterial geeignet sind.

According to one aspect of the present invention, there is provided an engine control unit for controlling an internal combustion engine to regenerate a particulate filter disposed in an exhaust system, the engine control unit comprising:

• at least one processor configured to receive a first signal from a first oxygen sensor for determining an oxygen content of an exhaust gas in the exhaust system downstream of the particulate filter and to receive a second signal from a second oxygen sensor disposed in the exhaust system upstream of the particulate filter, wherein the at least one processor is configured to compare the first and second signals to detect an increase or a decrease in the oxygen content of the exhaust gas in the exhaust system downstream of the particulate filter; and
• a memory device having instructions stored therein coupled to the at least one processor;
• wherein the at least one processor is configured to control the lambda (λ) of the internal combustion engine in response to an increase or a decrease in the oxygen content of the exhaust gas in the exhaust system downstream of the particulate filter. The exhaust system is connected to the internal combustion engine. In use, the exhaust gas of the internal combustion engine is passed through the exhaust system and flows through the particulate filter. The particulate filter traps carbonaceous particulate matter in the exhaust gas. To regenerate the particulate filter, the entrapped carbonaceous particulate material is oxidized and this process consumes oxygen. By monitoring the oxygen content of the exhaust gas downstream of the particulate filter, the engine control unit may determine that oxidation occurs in the particulate filter. The engine controller may possibly determine a rate at which oxidation occurs in the particulate filter to determine, for example, that the oxidation occurs at or above a predetermined threshold rate. The at least one processor is configured to control the internal combustion engine in response to an increase or decrease in the oxygen content of the exhaust gas in the exhaust system downstream of the particulate filter. The engine control unit may control the operation of the internal combustion engine to regenerate the particulate filter. In particular, the engine control unit may control the operation of the internal combustion engine so that the exhaust gases contain oxygen to oxidize carbonaceous particulate matter in the particulate filter. In at least certain embodiments, the engine control unit is operable to control the engine to promote the regeneration of the particulate filter when the prevailing conditions in the particulate filter are suitable for the oxidation of trapped particulate carbonaceous material.

The engine control unit finds particular use in a gasoline engine in which gasoline (motor gasoline) is burned, typically by spark ignition. In normal operation, the engine control unit can be configured to operate the (gasoline) internal combustion engine under stoichiometric conditions. In certain scenarios, e.g. During the active regeneration of the particulate filter, for example, the engine control unit may actively control the gasoline combustion engine to establish the conditions in the particulate filter for the oxidation of the particulate carbonaceous material. At least in certain embodiments, the control strategy described herein may reduce the frequency with which such active regeneration events may be required.

The first signal of the first oxygen sensor may include or consist of a first oxygen content signal. The at least one processor may be configured to detect changes in the oxygen content of the exhaust gas. The at least one processor may detect an increase or decrease in oxygen content. By monitoring the oxygen content of the exhaust gas downstream of the particulate filter, the at least one processor can detect when oxidation of the carbonaceous particulate matter is occurring. When the engine is operated under stoichiometric conditions (λ = 1), reducing the oxygen content of the exhaust downstream of the particulate filter may indicate that oxidation of the carbonaceous particulate material occurs within the particulate filter. The at least one processor may be configured to increase lambda (λ) when the comparison of the first and second signals indicates a decrease in the oxygen content of the exhaust in the exhaust system downstream of the particulate filter. The at least one processor may be configured to increase lambda (λ) when the comparison of the first and second signals indicates that the oxygen content of the exhaust gas in the exhaust system downstream of the particulate filter is less than or equal to a predefined oxygen content threshold. The predefined oxygen content threshold can be used as Zero (0) or greater than zero (0). When the engine is operated under stoichiometric conditions (λ = 1), increasing the oxygen content of the exhaust downstream of the particulate filter may indicate that the oxidation of the carbonaceous particulate material within the particulate filter is no longer occurring or the oxidation of the carbonaceous particulate material is reduced. The at least one processor may be configured to decrease lambda (λ) when the comparison of the first and second signals indicates an increase in the oxygen content of the exhaust in the exhaust system downstream of the particulate filter.

The second oxygen sensor may be referred to as an upstream oxygen sensor since it is located upstream of the particulate filter. The exhaust system may include a catalyst. The second oxygen sensor may be disposed between the catalyst and the particulate filter. The at least one processor may be configured to control the lambda (λ) of the internal combustion engine as a function of the detected increase or decrease in the oxygen content of the exhaust gas downstream of the particulate filter. The at least one processor may be configured to control the lambda (λ) of the internal combustion engine in response to a change in the first signal relative to the second signal. The at least one processor may be configured to control the lambda (λ) of the internal combustion engine in response to an increase or decrease in the first signal versus the second signal.

According to another aspect of the present invention, there is provided a vehicle including an engine control unit as described herein, an internal combustion engine, and an exhaust system having a particulate filter, wherein a first oxygen sensor in the exhaust system downstream of the particulate filter and a second oxygen sensor in the exhaust system upstream of the particulate filter for determining an oxygen content of the exhaust gas is provided. The particulate filter may be part of an aftertreatment system for treating exhaust gases emitted from the internal combustion engine.

The first oxygen sensor may be referred to as a downstream oxygen sensor since it is located downstream of the particulate filter. The first oxygen sensor may include a heated exhaust gas oxygen (HEGO) sensor. Alternatively, the first oxygen sensor may also include a heated broadband exhaust gas oxygen sensor (UHEGO (Universal Heating Exhaust Gas Oxygen) sensor).

The exhaust system may include a catalyst. The catalyst may be disposed between the engine and the particulate filter. The second oxygen sensor may be disposed in the exhaust system between the particulate filter and the catalyst. The second oxygen sensor may include a heated exhaust gas oxygen sensor (HEGO).

The first oxygen sensor may be provided in a first lambda probe located downstream of the particulate filter. The first lambda probe may be configured to generate a first lambda signal in response to a measured oxygen content of the exhaust gas.

The internal combustion engine may be a gasoline engine; and the particulate filter may be a gasoline particulate filter (GPF). The particulate filter may be a coated gasoline particulate filter (cGPF). In particular, a catalyst coating can be applied to the particulate filter. The catalyst coating may comprise a three-way catalyst (TWC). By controlling lambda in response to an increase or decrease in the oxygen content of the exhaust gas in the exhaust system downstream of the particulate filter, the treatment of NOx by the after-treatment system can be maintained during the regeneration of the particulate filter.

• Bestimmen eines Sauerstoffgehalts eines Abgases im Abgassystem stromabwärts des Partikelfilters;
• Bestimmen eines Sauerstoffgehalts des Abgases im Abgassystem stromaufwärts des Partikelfilters;
• Vergleichen des Sauerstoffgehalts des Abgases stromaufwärts und stromabwärts des Partikelfilters, um eine Verringerung oder eine Erhöhung des Sauerstoffgehalts des Abgases stromabwärts des Partikelfilters zu identifizieren; und
• Steuern von Lambda (λ) des Verbrennungsmotors in Abhängigkeit von einer Verringerung oder Erhöhung des Sauerstoffgehalts des Abgases stromabwärts des Partikelfilters.

According to another aspect of the present invention, there is provided a method of controlling an internal combustion engine to regenerate a particulate filter disposed in an exhaust system, the method comprising:

• Determining an oxygen content of an exhaust gas in the exhaust system downstream of the particulate filter;
• Determining an oxygen content of the exhaust gas in the exhaust system upstream of the particulate filter;
• Comparing the oxygen content of the exhaust gas upstream and downstream of the particulate filter to identify a decrease or an increase in the oxygen content of the exhaust gas downstream of the particulate filter; and
• Controlling lambda (λ) of the internal combustion engine in response to a decrease or increase in the oxygen content of the exhaust gas downstream of the particulate filter.

The method may include increasing lambda (λ) when a decrease in the oxygen content of the exhaust gas downstream of the particulate filter is detected.

The method may include decreasing lambda (λ) if an increase in the oxygen content of the exhaust gas downstream of the particulate filter is detected.

The method may include controlling lambda (λ) of the internal combustion engine as a function of the detected increase or decrease in the oxygen content of the exhaust gas downstream of the particulate filter. The method may include controlling lambda (λ) of the internal combustion engine in response to a change in the first signal relative to the second signal. The method may include controlling lambda (λ) of the internal combustion engine in response to an increase or decrease in the first signal versus the second signal.

According to another aspect of the present invention, there is provided an engine control unit for controlling an internal combustion engine to regenerate an exhaust particulate filter, the engine control unit comprising: at least one processor configured to generate a first signal from a first oxygen sensor to determine a first oxygen sensor Receive oxygen content of an exhaust gas in the exhaust system downstream of the particulate filter and to receive a second signal from a second oxygen sensor disposed in the exhaust system upstream of the particulate filter, wherein the at least one processor is configured to compare the first and second signal to a Increase or decrease the oxygen content of the exhaust gas in the exhaust system downstream of the particulate filter; and a memory device having instructions stored therein coupled to the at least one processor; wherein the at least one processor is configured to control the lambda of the internal combustion engine in response to the first signal.

The at least one processor may be configured to increase lambda when the first signal indicates a decrease in the oxygen content of the exhaust gas in the exhaust system downstream of the particulate filter.

The at least one processor may be configured to increase lambda when the first signal indicates that the oxygen content of the exhaust gas in the exhaust system downstream of the particulate filter is less than or equal to a predefined oxygen content threshold.

The at least one processor may be configured to decrease lambda when the received first signal indicates an increase in the oxygen content of the exhaust gas in the exhaust system downstream of the particulate filter.

According to another aspect of the present invention, there is provided a vehicle including an engine control unit according to an aspect of the present invention, an internal combustion engine and an exhaust system including a particulate filter; wherein a first oxygen sensor is provided in the exhaust system downstream of the particulate filter for determining an oxygen content of the exhaust gas. The first oxygen sensor may include a heated exhaust gas oxygen sensor. The exhaust system may include a catalyst disposed between the engine and the particulate filter. The second oxygen sensor may be disposed in the exhaust system between the particulate filter and the catalyst. The internal combustion engine may be a gasoline engine and the particulate filter may be a gasoline particulate filter. The particulate filter may be a coated gasoline particulate filter.

According to another aspect of the present invention, there is provided a method of controlling an internal combustion engine to regenerate a particulate filter disposed in an exhaust system, the method comprising: determining an oxygen content of an exhaust gas in the exhaust system downstream of the particulate filter; Determining an oxygen content of the exhaust gas in the exhaust system upstream of the particulate filter; Comparing the oxygen content of the exhaust gas upstream and downstream of the particulate filter to identify a decrease or an increase in the oxygen content of the exhaust gas downstream of the particulate filter; and controlling Lambda of the internal combustion engine as a function of the determined oxygen content of an exhaust gas in the exhaust system downstream of the particulate filter. The method may include increasing lambda as the determined oxygen content of the exhaust gas downstream of the particulate filter decreases. The method may include decreasing lambda as the determined oxygen content of the exhaust gas downstream of the particulate filter increases.

Any controller or controller described herein may suitably include a computing device having one or more electronic processors. The system may include a single controller or an electronic controller, or alternatively, various functions of the controller may be implemented in or included in various controllers or controllers. As used herein, the term "controller" or "controller" includes both a single controller or controller and a plurality of controllers or controllers that are operated together to provide a particular controller functionality. To configure a controller or control unit, an appropriate set of instructions may be provided which, when executed, the Control unit or the computing device to implement the control techniques described herein. The instruction set may be suitably embedded in the one or more electronic processors. Alternatively, the instruction set may also be provided as software stored in one or more memories associated with the controller for execution on the computing device. The controller or controller may be implemented in software running on one or more processors. One or more other controllers or controllers may be implemented in software executing on one or more processors, optionally on the same one or more processors as the first controller. Other suitable arrangements may be used.

It is expressly intended in the context of this application that the various aspects, embodiments, examples and alternatives set forth in the preceding paragraphs, in the claims and / or in the following description and the following drawings, and in particular the individual features thereof, independently can be used from each other or in any combination. That is, all embodiments and / or features of an embodiment may be combined in any manner and / or combination, unless these features are incompatible. The Applicant reserves the right to change a claim originally filed or to file a new claim, including the right to change an original claim, to become dependent on another claim and / or to include one feature in another claim, although it was not originally claimed that way.

list of figures

• 1 eine schematische Darstellung eines Fahrzeugs mit einer Motorsteuereinheit gemäß einer Ausführungsform der vorliegenden Erfindung zeigt;
• 2 eine schematische Darstellung des Abgassystems des in 1 dargestellten Fahrzeugs ist; und
• 3 eine Reihe von Diagrammen ist, die den Betrieb der Motorsteuereinheit gemäß einem Aspekt der vorliegenden Erfindung veranschaulichen.

One or more embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

• 1 shows a schematic representation of a vehicle with a motor control unit according to an embodiment of the present invention;
• 2 a schematic representation of the exhaust system of in 1 shown vehicle is; and
• 3 Figure 5 is a series of diagrams illustrating the operation of the engine control unit according to one aspect of the present invention.

DETAILED DESCRIPTION

A vehicle 1 according to one embodiment of the present invention is in 1 shown. The vehicle 1 includes an internal combustion engine 2 with an exhaust system 3 for guiding exhaust gases from the internal combustion engine 2 , The vehicle 1 in the present embodiment is an automobile, but the present invention can be usefully employed in other types of vehicles.

The internal combustion engine 2 is a gasoline engine that burns gasoline in one or more combustion chambers (not shown). In the present embodiment, the internal combustion engine 2 a gasoline light engine designed to operate under stoichiometric conditions. The exhaust gases from the combustion cycle are removed from the internal combustion engine 2 in the exhaust system 3 for treatment by aftertreatment systems (designated by reference number 4 ), including a catalyst 5 and a gasoline particle filter (GPF) 6 , The catalyst 5 is a three-way catalyst (TWC) and is used to combine oxygen ( 02 ) with carbon monoxide (CO) and unburned hydrocarbons (UHC) and for the reduction of nitrogen oxides (NOx), in particular monoxide oxides nitrogen monoxide (NO) and nitrogen dioxide ( N02 ). The GPF 6 collects carbonaceous particulate matter from the exhaust gas. The carbonaceous particulate material may include or consist of carbon black. The GPF 6 in the present embodiment is a coated gasoline particle filter (cGPF) with a catalyst coating. The GPF 6 is regenerated by oxidation of the entrapped carbonaceous particulate material. The oxidation process requires oxygen and a high temperature, eg. B. a temperature greater than or equal to 500 ° C or 600 ° C.

The vehicle 1 includes a motor control unit 7 for controlling the operation of the internal combustion engine 2 , The engine control unit 7 includes a processor 8th that with a storage device 9 connected is. The processor 8th is configured to implement a set of persistent computing instructions residing on the storage device 9 are stored. When the computational instructions are executed, they cause the processor to perform an engine control strategy to control the operation of the internal combustion engine 2 to implement. The processor 8th is configured to provide a lambda control signal CON1 for controlling lambda (λ) of the internal combustion engine 2 issue. Lambda (λ) is the ratio of the actual air-fuel ratio (AFR) to the stoichiometric air-fuel ratio (AFR _stoich ) and is defined by the following equation: $$\mathrm{\lambda }=\frac{\text{AFR}}{\text{AFR}stOicH}$$

As described above, the internal combustion engine 2 configured for operation under stoichiometric conditions, ie lambda (λ) is at least substantially equal to one (1). The lambda control signal CON1 can be the lambda (λ) of the internal combustion engine 2 increase or decrease. By varying the lambda (λ), the content of the from the internal combustion engine 2 discharged exhaust gas are selectively controlled. To ensure efficient operation of the aftertreatment systems 4 Maintain is the engine control unit 7 configured to adjust lambda (λ) to the oxygen content of the exhaust system 3 to control introduced exhaust gas.

With reference to 2 is the engine control unit 7 with a first oxygen sensor 10 a second oxygen sensor 11 and a third oxygen sensor 12 connected. The first and second oxygen sensor 10 . 11 In the present embodiment, each includes a heated exhaust gas oxygen (HEGO) sensor (also called lambda probes or "narrowband" sensors). The first oxygen sensor 10 is in the exhaust system 3 downstream of the GPF 6 arranged. The second oxygen sensor 11 is in the exhaust system 3 downstream of the catalyst 5 and upstream of the GPF 6 arranged. The third oxygen sensor 12 in the present embodiment includes a heated broadband exhaust gas oxygen sensor (UHEGO (Universal Heating Exhaust Gas Oxygen) sensor (also referred to as a universal lambda probe or "wideband probe"). The third oxygen sensor 12 is in the exhaust system 3 between the internal combustion engine 2 and the catalyst 5 arranged. The first oxygen sensor 10 , the second oxygen sensor 11 and the third oxygen sensor 12 are designed to monitor the oxygen content of the exhaust gas. The first, second and third oxygen sensor 10 . 11 . 12 are configured to receive the respective first, second and third oxygen content signals SIG1 . SIG2 . SIG3 to the engine control unit 7 issue. The first, second and third oxygen content signal SIG1 . SIG2 . SIG3 provide feedback to the engine control unit 7 , which is a closed-tank fueling control strategy for controlling lambda (λ) of the internal combustion engine 2 implemented. One or more of the first, second, and third oxygen content signals SIG1 . SIG2 . SIG3 can be used for on-board diagnostics (OBD).

The engine control unit 7 is configured to control the fuel supply of the internal combustion engine 2 to control the stoichiometric operation (λ = 1). The engine control unit 7 operates in a conventional manner depending on the second and third oxygen content signal SIG2 . SIG3 , In accordance with one aspect of the present invention, the first oxygen content signal provides SIG1 also a feedback to the engine control unit 7 , When the temperature of the GPF 6 high enough and oxygen is present in the exhaust gas, that is in the GPF 6 enclosed carbonaceous particulate material oxidizes. The oxidation process reduces the oxygen content of the exhaust gas and this change in oxygen content can be downstream of the GPF 6 through the first oxygen sensor 10 be recorded. It is understood that carbon monoxide (CO) and / or unburned hydrocarbons (UHC) also in the GPF 6 can be oxidized and these processes also consume oxygen.

During operation of the internal combustion engine 2 which aims at stoichiometric conditions is a reduction in the oxygen content of the exhaust gas downstream of the GPF 6 an indicator that oxidation of the carbonaceous particulate material within the GPF 6 took place (or takes place). Upon detecting a reduction in oxygen content, the engine control unit is 7 configured to adjust lambda (λ) to promote oxidation of the carbonaceous particulate material. In particular, when the first oxygen content signal SIG1 a decrease in the oxygen content downstream of the GPF 6 indicates is the engine control unit 7 configured to increase lambda (λ). An increasing lambda (λ) causes a balance to lean on the internal combustion engine 2 is applied. A corresponding increase in the oxygen content of the exhaust gas contributes to oxygen for the oxidation of the carbonaceous particulate material in the GPF 6 is available while the stoichiometric conditions throughout the aftertreatment system 4 remain. The engine control unit 7 Lambda (λ) may be controlled to maintain a predetermined oxygen content in the exhaust gas as determined by the closed loop feedback loop associated with the first oxygen sensor 10 was produced.

During operation of the internal combustion engine 2 which aims at stoichiometric conditions is an increase in the oxygen content of the exhaust gas downstream of the GPF 6 an indicator that no oxidation of the carbonaceous particulate material takes place any more. For example, the oxidation of the carbonaceous particulate material may be completed or the temperature of the GPF 6 have sunk. The engine control unit 7 monitors the first oxygen content signal SIG1 and decreases lambda (λ) when an increase in oxygen content is detected.

In normal (stoichiometric) operation of the internal combustion engine 2 There is typically a small amount of oxygen present in the exhaust gas, which is responsible for the oxidation of carbon monoxide (CO) and unburned hydrocarbons (UHC) in the catalyst 5 is used. The third oxygen sensor 12 and the second oxygen sensor 11 are used to detect when the available oxygen is fully utilized and to increase lambda (λ) in the combustion engine 2 to bring about a corresponding emaciation. Any oxygen in the exhaust downstream of the catalyst 5 allows the oxidation of a small amount of the carbonaceous particulate material in the GPF 6 provided the temperature of the GPF 6 is high enough. The second and third oxygen sensor 11 . 12 work actively for the oxidation of the carbonaceous particulate material in the GPF 6 reduce available amount of oxygen. By using the first oxygen sensor 10 who is behind the GPF 6 is arranged to implement an additional lambda (λ) control, the engine control unit 7 the oxygen used to oxidize the carbonaceous particulate material in the GPF 6 is used, recognize and react to. The engine control unit 7 is configured to modify lambda (λ) to increase the oxidation of the carbonaceous particulate material. In particular, the engine control unit 7 configured to the lambda (λ) of the internal combustion engine 2 depending on the detection of a reduction in the oxygen content of the exhaust gas downstream of the GPF 6 to increase. The engine control unit 7 can thereby the fuel supply of the internal combustion engine 2 control to stoichiometric overall conditions throughout the aftertreatment system 4 provide. At least in certain embodiments, increasing the lambda (λ) of the internal combustion engine results in additional oxygen in the exhaust gas for oxidation of carbonaceous particulate material in the GPF 6 is included. This may help to prevent the accumulation of carbonaceous particulate matter over a wider range of operating cycles and / or reduce the requirement / frequency of active regeneration events. The maintenance of the stoichiometric conditions allows the reduction of nitrogen oxides (NOx) and the oxidation of carbon monoxide (CO) and hydrocarbons (HC) in the catalyst 5 and the oxidation of the carbonaceous particulate material in the GPF 6 , The engine control unit 7 can be configured to control the oxidation of the carbonaceous particulate material as well as the conversion of gaseous emissions during stoichiometric operation of the internal combustion engine 2 to improve.

The operation of the engine control unit 7 will now be based on 3 described. A first diagram 105 shows a temperature diagram for the GPF 6 ; a second diagram 110 shows an oxygen content (%) of the exhaust gas downstream of the GPF 6 ; and a third diagram 115 shows lambda (λ) emitted by the engine control unit 7 was set. As in the first diagram 105 shown, the temperature of the GPF rises 6 until sufficient, the oxidation of the carbonaceous particulate material in the GPF 6 initiate (time t = t1). The oxidation of the carbonaceous particulate material reduces the oxygen content of the exhaust gas downstream of the GPF 6 , The measurement of the oxygen content by the first oxygen sensor 10 is in the second diagram 110 shown. The engine control unit 7 controls lambda (λ) as a function of the first oxygen content signal SIG1 , In particular, the engine control unit increases 7 Lambda (λ) when a decrease in oxygen content is detected (time t = t2) as in the third graph 115 shown. The resulting emaciation of the internal combustion engine 2 causes an increase in the oxygen content of the exhaust gas supplied to the GPF and thus contributes to the oxidation of the carbonaceous particulate material. The engine control unit 7 Also controls Lambda (λ) as a function of the measured oxygen content of the exhaust gas downstream of the GPF 6 , In particular, lambda (λ) may be controlled to determine the oxygen content of the exhaust gas downstream of the GPF 6 essentially constant, as in the second diagram 110 (Time t2-t3). For example, lambda (λ) may be controlled to maintain the oxygen content at a predetermined level suitable for the oxidation of the carbonaceous particulate material. Alternatively, lambda (λ) may be controlled to determine the oxygen content of the exhaust gas downstream of the GPF 6 to increase. The engine control unit 7 monitors the first oxygen content signal SIG1 and decreases lambda (λ) when an increase in oxygen content is detected (time t = t3), as in the third diagram 115 shown.

The engine control unit 7 The decrease of the oxygen content can only depend on the first oxygen content signal SIG1 to capture. Alternatively, the engine control unit 7 the reduction of the oxygen content as a function of the first and second oxygen content signal SIG1 . SIG2 capture, z. B. by comparing the oxygen content of the in the GPF 6 introduced exhaust gas with the oxygen content of the GPF 6 exiting exhaust gas.

At least in certain embodiments, the engine control unit 7 according to the present invention, the oxidation of the carbonaceous particulate material in the GPF 6 improve, for example, during prolonged operation without fuel supply interruption by fuel cut. The accumulation of carbonaceous particulate material in the GPF 6 can be partially or fully reduced over a wider range of operating cycles, which can also reduce the requirements / frequency of active regeneration events. In any operation where the exhaust gas / GPF temperature is not high enough to oxidize the carbonaceous particulate material or there is no carbonaceous particulate material to be oxidized, no oxygen is consumed and the closed loop fuel control strategy operates as usual for the catalyst 5 and the GPF 6 ,

It should be noted that on the engine control unit described herein 7 Various changes and modifications may be made without departing from the scope of the present invention. The embodiment described herein includes a coated GPF 6 , In alternative embodiments, an uncoated GPF may be downstream of the catalyst 5 be used.

The engine control unit 7 has been described herein as being the lambda (λ) of the internal combustion engine 2 depending on the detection of a reduction in the oxygen content of the exhaust gas downstream of the GPF 6 elevated. Alternatively or additionally, the engine control unit 7 be configured to the lambda (λ) of the internal combustion engine 2 depending on whether the oxygen content of the exhaust gas downstream of the GPF 6 is below a predetermined oxygen content threshold.

The engine control unit 7 is described herein as being a first signal SIG1 from a first oxygen sensor 10 which is downstream of the GPF 6 is arranged. It is understood that the first oxygen sensor 10 can be provided in a first lambda probe. In this arrangement, the lambda probe may output a lambda signal to the engine control unit 7 Depending on the measured oxygen content of the exhaust gas downstream of the GPF 6 is produced. The engine control unit 7 can be configured to the lambda (λ) of the internal combustion engine 2 in response to this lambda signal. A reduction in the measured oxygen content of the exhaust gas downstream of the GPF 6 leads to a reduction of the lambda signal. It is therefore understood that the operation of the engine control unit 7 essentially unchanged in this arrangement. In particular, the engine control unit 7 be configured to the lambda (λ) of the internal combustion engine 2 increase when the first signal SIG1 a decrease in the lambda signal from downstream of the GPF 6 arranged lambda sensor indicates.

The present invention has been more particularly related to a gasoline light engine 2 described, which is designed for operation under stoichiometric conditions. It will be understood that the present invention relates to spark-ignition internal combustion engines 2 can be used which burn fuels other than gasoline under stoichiometric conditions. For example, the internal combustion engine could 2 be designed to use compressed natural gas (CNG), alcohol or liquefied petroleum gas (LPG) as the fuel source.

Claims (26)

An engine control unit for controlling an internal combustion engine to regenerate a particulate filter disposed in an exhaust system, the engine control unit comprising: at least one processor configured to receive a first signal from a first oxygen sensor for determining an oxygen content of an exhaust gas in the exhaust system downstream of the particulate filter and to receive a second signal from a second oxygen sensor disposed in the exhaust system upstream of the particulate filter, wherein the at least one processor is configured to compare the first and second signals to detect an increase or a decrease in the oxygen content of the exhaust gas in the exhaust system downstream of the particulate filter; and a memory device having instructions stored therein coupled to the at least one processor; wherein the at least one processor is configured to control the lambda of the internal combustion engine in response to an increase or a decrease in the oxygen content of the exhaust gas in the exhaust system downstream of the particulate filter. Engine control unit after Claim 1 wherein the at least one processor is configured to increase lambda when the comparison of the first and second signals indicates a decrease in the oxygen content of the exhaust gas in the exhaust system downstream of the particulate filter. Engine control unit after Claim 1 or Claim 2 wherein the at least one processor is configured to increase lambda when the comparison of the first and second signals indicates that the oxygen content of the exhaust gas in the exhaust system downstream of the particulate filter is less than or equal to a predefined oxygen content threshold. Engine control unit according to one of Claims 1 . 2 or 3 wherein the at least one processor is configured to decrease lambda when the comparison of the first and second signals is an increase indicates the oxygen content of the exhaust gas in the exhaust system downstream of the particulate filter. A vehicle comprising an engine control unit according to any one of the preceding claims, an internal combustion engine and an exhaust system having a particulate filter; wherein a first oxygen sensor in the exhaust system downstream of the particulate filter and a second oxygen sensor in the exhaust system upstream of the particulate filter for determining an oxygen content of the exhaust gas is provided. Vehicle after Claim 5 wherein the first oxygen sensor comprises a heated exhaust gas oxygen sensor. Vehicle after Claim 5 or Claim 6 wherein the exhaust system comprises a catalyst disposed between the engine and the particulate filter. Vehicle after Claim 7 wherein the second oxygen sensor is disposed in the exhaust system between the particulate filter and the catalyst. Vehicle after one of the Claims 5 to 8th wherein the internal combustion engine is a gasoline engine; and the particulate filter is a gasoline particulate filter. Vehicle after Claim 9 wherein the particulate filter is a coated gasoline particulate filter. A method of controlling an internal combustion engine to regenerate a particulate filter disposed in an exhaust system, the method comprising: Determining an oxygen content of an exhaust gas in the exhaust system downstream of the particulate filter; Determining an oxygen content of the exhaust gas in the exhaust system upstream of the particulate filter; Comparing the oxygen content of the exhaust gas upstream and downstream of the particulate filter to identify a decrease or an increase in the oxygen content of the exhaust gas downstream of the particulate filter; and Controlling lambda of the internal combustion engine in response to a decrease or increase in the oxygen content of the exhaust gas downstream of the particulate filter. Method according to Claim 11 comprising increasing lambda when a decrease in the oxygen content of the exhaust gas downstream of the particulate filter is identified. Method according to Claim 11 or 12 comprising reducing lambda when an increase in the oxygen content of the exhaust gas downstream of the particulate filter is identified. An engine control unit for controlling an internal combustion engine to regenerate a particulate filter disposed in an exhaust system, the engine control unit comprising: at least one processor configured to receive a first signal from a first oxygen sensor for determining an oxygen content of an exhaust gas in the exhaust system downstream of the particulate filter and to receive a second signal from a second oxygen sensor disposed in the exhaust system upstream of the particulate filter, wherein the at least one processor is configured to compare the first and second signals to detect an increase or a decrease in the oxygen content of the exhaust gas in the exhaust system downstream of the particulate filter; and a memory device having instructions stored therein coupled to the at least one processor; wherein the at least one processor is configured to control the lambda of the internal combustion engine in response to the first signal. Engine control unit after Claim 14 wherein the at least one processor is configured to increase lambda when the first signal indicates a decrease in the oxygen content of the exhaust gas in the exhaust system downstream of the particulate filter. Engine control unit after Claim 14 or Claim 15 wherein the at least one processor is configured to increase lambda when the first signal indicates that the oxygen content of the exhaust gas in the exhaust system downstream of the particulate filter is less than or equal to a predefined oxygen content threshold. Engine control unit according to one of Claims 14 . 15 or 16 wherein the at least one processor is configured to decrease lambda when the received first signal indicates an increase in the oxygen content of the exhaust gas in the exhaust system downstream of the particulate filter. Vehicle with an engine control unit according to one of Claims 14 to 17 , an internal combustion engine and an exhaust system with a particulate filter; wherein a first oxygen sensor is provided in the exhaust system downstream of the particulate filter for determining an oxygen content of the exhaust gas. Vehicle after Claim 18 wherein the first oxygen sensor comprises a heated exhaust gas oxygen sensor. Vehicle after Claim 18 or Claim 19 wherein the exhaust system comprises a catalyst disposed between the engine and the particulate filter. Vehicle after Claim 20 wherein the second oxygen sensor is disposed in the exhaust system between the particulate filter and the catalyst. Vehicle after one of the Claims 18 to 21 wherein the internal combustion engine is a gasoline engine; and the particulate filter is a gasoline particulate filter. Vehicle after Claim 22 wherein the particulate filter is a coated gasoline particulate filter. A method of controlling an internal combustion engine to regenerate a particulate filter disposed in an exhaust system, the method comprising: Determining an oxygen content of an exhaust gas in the exhaust system downstream of the particulate filter; Determining an oxygen content of the exhaust gas in the exhaust system upstream of the particulate filter; Comparing the oxygen content of the exhaust gas upstream and downstream of the particulate filter to identify a decrease or an increase in the oxygen content of the exhaust gas downstream of the particulate filter; and Controlling lambda of the internal combustion engine as a function of the determined oxygen content of an exhaust gas in the exhaust system downstream of the particulate filter. Method according to Claim 24 comprising increasing lambda as the determined oxygen content of the exhaust gas downstream of the particulate filter decreases. Method according to Claim 24 or Claim 25 comprising decreasing lambda as the determined oxygen content of the exhaust gas increases downstream of the particulate filter.

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