DE102019122370A1 - Internal combustion engine with an exhaust aftertreatment system with a temporary storage unit - Google Patents

Abstract

The invention relates to an internal combustion engine (1) comprising an exhaust aftertreatment system (2), the exhaust aftertreatment system (2) comprising a temporary storage unit (3). and wherein the temporary storage unit (3) is designed to store exhaust gas temporarily.

Description

The invention relates to an internal combustion engine having an exhaust gas aftertreatment system with an intermediate storage unit for storing exhaust gases and a method for exhaust gas purification of an internal combustion engine.

From the EP 3 029 289 B1 An exhaust aftertreatment system for a vehicle operated by an internal combustion engine is known, wherein at least one storage device is arranged upstream of at least one turbine in an exhaust line for storing and / or temporarily storing sulfur pollutants in a high-pressure region.

The internal combustion engine according to the invention comprises an exhaust aftertreatment system. The exhaust aftertreatment system includes a buffer unit. The intermediate storage unit is designed to temporarily store exhaust gas. By virtue of the fact that the intermediate storage unit is designed to temporarily store exhaust gas, the invention enables the intermediate storage unit to be filled under operating conditions of inadequate functionality of the exhaust aftertreatment system, and in advantageous operating conditions, the intermediate storage unit can be emptied again via the exhaust gas aftertreatment system.

Inadequate functionality of the exhaust aftertreatment system is especially in cold start or warm-up conditions when a light-off temperature of a component of the exhaust aftertreatment system is not reached. Advantageous operating conditions are present when all components of the exhaust aftertreatment system have reached their light-off temperature. The light-off temperature of a component of the exhaust aftertreatment system is the temperature at which a conversion rate of a pollutant is 50%. The intermediate storage unit is preferably arranged downstream of an exhaust gas turbine of the exhaust gas aftertreatment system. Exhaust discharged from the intermediate storage unit is preferably supplied to the main exhaust gas stream upstream of the exhaust aftertreatment system. Temporary storage means that the exhaust gas is stored in the temporary storage unit for a period of time. This time span is less than 10,000 seconds, preferably less than 2,500 seconds, more preferably less than 1,000 seconds. As components of the exhaust aftertreatment system, in particular 3-way catalysts, diesel oxidation catalysts, SCR (Selective Catalytic Reduction) catalysts and / or NO _x storage catalysts are understood.

Preferably, the buffer unit comprises a tank, an inlet valve and an outlet valve. The inlet and outlet valves allow the control of the temporary storage of exhaust gas in the intermediate storage unit.

• - Ermitteln eines Betriebspunkts und eines Betriebszustandes des Verbrennungsmotors,
• - Ermitteln eines Zustands eines Abgasnachbehandlungssystems des Verbrennungsmotors,
• - Befüllen einer Zwischenspeichereinheit des Verbrennungsmotors in Abhängigkeit des ermittelten Betriebspunkts und des ermittelten Zustands und
• - Entleeren der Zwischenspeichereinheit in Abhängigkeit des ermittelten Betriebspunkts und des ermittelten Zustands.

The inventive method for exhaust gas purification of an internal combustion engine comprises the following steps:

• Determining an operating point and an operating state of the internal combustion engine,
• Determining a state of an exhaust aftertreatment system of the internal combustion engine,
• - Filling a buffer unit of the internal combustion engine in dependence of the determined operating point and the determined state and
• - Emptying the intermediate storage unit depending on the determined operating point and the determined state.

Characterized in that the filling and emptying of the temporary storage unit in dependence of the determined operating point and the determined operating state of the internal combustion engine and the determined state of the exhaust aftertreatment system, the invention enables a demand-based buffering of exhaust gas, so that the emission of pollutants can be reduced in the environment. In particular, in cold start and warm-up conditions, the invention can thus contribute to meeting certification-relevant pollutant emissions. The determination of an operating state of the internal combustion engine preferably comprises the detection of temperatures and the detection of a stationary or transient operation.

The dependent claims describe further advantageous embodiments of the invention.

• 1 ein Ausführungsbeispiel eines erfindungsgemäßen Verbrennungsmotors,
• 2 ein alternatives Ausführungsbeispiel eines erfindungsgemäßen Verbrennungsmotors und
• 3 ein Ausführungsbeispiel eines erfindungsgemäßen Verfahrens.

Preferred embodiments will be explained in more detail with reference to the following figures. It shows

• 1 an embodiment of an internal combustion engine according to the invention,
• 2 an alternative embodiment of an internal combustion engine according to the invention and
• 3 an embodiment of a method according to the invention.

1 shows an internal combustion engine 1 , The internal combustion engine 1 includes an exhaust aftertreatment system 2 , wherein the exhaust aftertreatment system 2 a cache unit 3 includes. The cache unit 3 is designed to temporarily store exhaust gas. The cache unit 3 includes a tank 4 , an inlet valve 5 . an outlet valve 6 and a compressor 7 , where the tank 4 designed as a high-pressure storage tank to reduce the space requirement.

The cache unit 3 is filled in operating conditions inadequate functionality of the exhaust aftertreatment system and emptied in advantageous operating conditions through the exhaust aftertreatment system. Inadequate functionality exists when a light-off temperature of a component 12 the exhaust aftertreatment system 2 is not reached. Advantageous operating conditions exist when all components 12 the exhaust aftertreatment system 2 have reached their respective light-off temperature. The light-off temperature of a component 12 is the temperature at which 50% of pollutants are converted.

The compressor 7 is formed, the intermediate storage unit 3 to fill with exhaust gas. Here is the temporary storage unit 3 downstream of a component 12 the exhaust aftertreatment system 2 arranged. The exhaust aftertreatment system 2 further comprises an exhaust gas turbocharger 13 , four combustion cylinders 14 and a high pressure exhaust gas recirculation 15 and a low pressure exhaust gas recirculation 16 , The outlet valve 6 is formed, the intermediate storage unit 3 to empty and the exhaust discharged upstream of an exhaust gas turbine 17 the exhaust gas turbocharger 13 to supply the main exhaust gas stream.

The internal combustion engine 1 allows emission reduction, especially during cold start or warm-up conditions. In addition, the need for engine internal heating measures to increase the temperature of the exhaust aftertreatment system, which has an advantageous effect on fuel consumption. With cold start and warm-up conditions, less EGR can be applied, allowing for fuel economy benefits and reduced soot emissions. The internal combustion engine 1 is designed as a diesel engine and includes as components 12 a DOC and a SCR. Alternatively or additionally, an LNT may also be included. The internal combustion engine can also be designed as a gasoline engine, wherein the component 12 then may comprise a 3-way catalyst.

2 shows a variant of an internal combustion engine 1 , The cache unit 3 includes in addition to the in picture 1 features shown an electrical memory 8th , where the compressor 7 is electrically designed and wherein the electrical storage 8th is formed, the compressor 7 to power electrically. In a variant of an internal combustion engine, not shown 1 will be in place of the electrical storage 8th an existing battery, here a 48 volt system, used. In another variant, not shown, of an internal combustion engine 1 is the compressor 7 mechanically translated. Also other non-electrical embodiments of the compressor 7 are conceivable.

In the in 2 shown variant of an internal combustion engine 1 includes the temporary storage unit 3 a turbine 9 and a generator 10 , where the generator 10 with the turbine 9 is electrically coupled and wherein the generator 10 is formed, electrical energy to the electrical storage 8th supply. The turbine 9 is formed, exhaust gas when emptying the intermediate storage unit 3 is dissipated to expand. So can one for the compressor 7 required compression work to be recovered at least partially as a result of the expansion work. The one of the turbine 9 electrically coupled generator 10 Energy gained in the electrical storage 8th be stored and for the compressor 7 be used. Alternatively, the electrical storage can also be used for other consumers. The turbine 9 is designed with a variable turbine geometry, so that the turbine efficiency can be optimized depending on a flow state.

The internal combustion engine 1 includes a controller 11 , The control unit 11 is set up and trained, filling and emptying operations of the temporary storage unit 3 depending on an operating point of the internal combustion engine 1 and a state of the exhaust aftertreatment system 2 to control. This is the control unit 11 designed and set up, the inlet valve 5 , the exhaust valve 5 , the compressor 7 and the turbine 9 to actuate.

• - Ermitteln eines Betriebspunktes und eines Betriebszustands S10 des Verbrennungsmotors 1,
• - Ermitteln eines Zustands S20 eines Abgasnachbehandlungssystems 2 des Verbrennungsmotors 1,
• - Befüllen S30 einer Zwischenspeichereinheit 3 des Verbrennungsmotors 1 in Abhängigkeit des ermittelten Betriebspunkts S10 und des ermittelten Zustands S20 und
• - Entleeren S40 der Zwischenspeichereinheit 3 in Abhängigkeit des ermittelten Betriebspunkts S10 und des ermittelten Zustands S20.

3 shows a method for exhaust gas purification of an internal combustion engine 1 , The method comprises the following steps:

• - Determining an operating point and an operating state S10 of the internal combustion engine 1 .
• - Determining a state S20 an exhaust aftertreatment system 2 of the internal combustion engine 1 .
• - Fill S30 a cache unit 3 of the internal combustion engine 1 depending on the determined operating point S10 and the determined state S20 and
• - emptying S40 the cache unit 3 depending on the determined operating point S10 and the determined state S20 ,

Determining the operating point and operating state S10 and the condition S20 is done by sensors (not shown). Alternatively, models, maps and / or a Combination of sensor data, models and / or maps are used. A control unit program causes the filling S30 and emptying S40 the buffer unit depending on the determined operating point and the determined operating state S10 and the determined state S20 ,

The ECU program takes into account when filling S30 and emptying S40 predictive mechanisms. Predictive mechanisms include filling S30 and emptying S40 taking into account future events, for example based on positioning information, a radar, a sensor or other data. The information here includes environmental conditions from a navigation system, traffic light circuits and behavior of other road users.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 3029289 B1 [0002]

Claims (10)

An internal combustion engine (1) comprising an exhaust aftertreatment system (2), wherein the exhaust aftertreatment system (2) comprises a temporary storage unit (3) and wherein the temporary storage unit (3) is configured to temporarily store exhaust gas. Internal combustion engine (1) after Claim 1 wherein the buffer unit (3) comprises a tank (4), an inlet valve (5) and an outlet valve (6). Internal combustion engine (1) after Claim 2 , wherein the tank (4) is designed as a high-pressure storage tank. Internal combustion engine (1) according to one of the preceding claims, wherein the temporary storage unit (3) comprises a compressor (7). Internal combustion engine (1) after Claim 4 in which the intermediate storage unit (3) comprises an electrical store (8), wherein the compressor (7) is designed electrically and wherein the electrical store (8) is designed to electrically drive the compressor (7). Internal combustion engine (1) according to one of the preceding claims, wherein the intermediate storage unit (3) comprises a turbine (9). Internal combustion engine (1) after Claim 6 wherein the buffer unit (3) comprises a generator (10), wherein the generator (10) is electrically coupled to the turbine (9) and wherein the generator (10) is adapted to supply electrical energy to the electrical storage (8). Internal combustion engine (1) according to one of the preceding claims, comprising a control unit (11), wherein the control unit (11) is set up and designed to control a filling and emptying operation of the temporary storage unit (3). Process for the exhaust gas purification of an internal combustion engine (1), comprising the following steps: Determining an operating point and an operating state (S10) of the internal combustion engine (1), Determining a state (S20) of an exhaust aftertreatment system (2) of the internal combustion engine (1), - Filling (S30) of a buffer unit (3) of the internal combustion engine (1) in dependence of the determined operating point (S10) and the determined state (S20) and - Emptying (S40) of the temporary storage unit (3) as a function of the determined operating point (S10) and the determined state (S20). Method according to Claim 9 , where during filling (S30) and emptying (S40) predictive mechanisms are taken into account.

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