Internal combustion engine and method for particulate matter emissions

Abstract

The present invention relates to an internal combustion engine (1). The internal combustion engine comprises at least two cylinders (2). Each of the two cylinders comprises a combustion chamber (3) and also has an exhaust gas outlet (5) having a fuel inlet and outlet valve (6). The internal combustion engine comprises at least one separation device (7) for separating the exhaust gas from all combustion chambers (3) into first and second exhaust gas streams downstream of the combustion chamber (3). A first exhaust line (8) and a second exhaust line (9) are connected to at least one separation device (7). The at least one separation device (7) is configured to separate the exhaust gas from the combustion chamber (3) into a first gas stream for the first component exhaust line (8) and a second gas stream for the second component exhaust line (9). A particulate matter reduction device (10) is positioned downstream of the separation device (7) on the first component exhaust line (8). The separation device (7) is configured to separate exhaust gas from the combustion chamber (3) into, preferably, a first gas stream for a first component exhaust line (8), and preferably, a second gas stream for a second component exhaust line (9), and the temperature of the second gas stream is lower than the temperature of the first gas stream.

Description

Technology Field

[0001] The present invention relates to a method for reducing internal combustion engine and particulate matter emissions according to the preamble of an independent claim.

[0002] The present invention relates to the technical field of combustion engines and the reduction of their emissions. Background Technology

[0003] Emission requirements for large vessels are becoming stricter, particularly regarding nitrogen oxide emissions. Stricter regulations on particulate matter are also expected to be introduced. Therefore, it is necessary to reliably reduce the amount of particulate matter in the exhaust gases emitted by the internal combustion engines of these vessels.

[0004] Current particulate matter reduction technologies are limited by the temperature range required for oxidation reactions during the thermal regeneration of particulate matter reduction devices, such as filters. When the exhaust gas temperature is lower and the load is generally low, the thermal regeneration of the particulate matter reduction device is degraded and becomes insufficient.

[0005] When a particulate matter reduction device is not thermally regenerated or is thermally regenerated only in a limited manner, the performance of the device will degrade, and maintenance measures will also be required at shorter time intervals.

[0006] The regeneration of particulate matter reduction devices is generally based on the oxidation of carbon-based soot particles. The problem to be solved

[0007] The objective of the present invention is to prevent the disadvantages of the prior art and, in particular, to reliably reduce particulate emissions in the exhaust gas of an internal combustion engine even at low engine loads. A further specific objective of the present invention is to provide flexible and efficient reduction of particulate emissions for different engine loads. means of solving the problem

[0008] According to a first aspect of the present invention, an internal combustion engine is provided. The internal combustion engine is preferably a two-stroke engine. The engine is particularly suitable for a propulsion system, e.g., a propulsion system of a ship. The internal combustion engine comprises at least two cylinders. Each of the two cylinders comprises a combustion chamber and has an exhaust gas outlet having fuel inlet and outlet valves. The internal combustion engine comprises at least one separator downstream of the combustion chamber. First and second exhaust lines are connected to at least one separator. The at least one separator is configured to separate the exhaust gas from each combustion chamber into a first gas stream for a first component exhaust line and a second gas stream for a second component exhaust line. A particulate matter reduction device is disposed downstream of the separator in the first component exhaust line. The second component exhaust line and the first component exhaust line are separate from each other at least up to the particulate matter reduction device.

[0009] The particulate matter reduction device may include a filter, such as a deep bed or wall flow filter, and a device for oxidizing unburned hydrocarbons and other volatile carbon components.

[0010] Additionally, a first selective catalytic reduction (SCR) reactor may be placed in the first component exhaust line downstream of the separation device, particularly downstream of the particulate matter reduction device. Preferably, a device for injecting a reducing agent, such as a urea solution, is placed upstream of the first SCR reactor.

[0011] The first SCR reactor preferably has a maximum capacity of no more than 80% of the full-load output of at least two cylinders. Preferably, the first SCR reactor preferably has a maximum capacity of no more than 60% or 50% of the full-load output of at least two cylinders. Full load may be the operating condition of an internal combustion engine where the internal combustion engine provides maximum power or torque. If power or torque is lowered due to a reduction in energy supply, this operating condition is called partial load. Full load is the engine's condition maximum continuous tating (CMCR) point. In one embodiment, full load (e.g., CMCR) is calculated using the desired vessel speed, desired power, and optionally the desired propeller speed.

[0012] The separation device is configured to separate the exhaust gas into two streams. Since only a portion of the exhaust gas is sent to the first SCR reactor, a smaller SCR reactor can be selected. A large SCR reactor imposes significant constraints on the engine configuration. Large SCRs are expensive, difficult to integrate into the engine, and consequently result in a loss of fuel efficiency. Since only a portion of the exhaust gas is guided through the SCR, space and costs can be reduced.

[0013] In a two-stroke engine, supercharged air is compressed, fuel is injected, and the mixture is burned in the cylinder. The gas mixture produced by combustion in the cylinder is hereinafter referred to as "combustion gas." Combustion gas may also contain particulate matter.

[0014] Scavenge air is used to expel combustion gases from the combustion chamber through the outlet. The combination of scavenge air and combustion gases is expelled through the outlet of the cylinder and is commonly referred to as "exhaust gas."

[0015] Due to scavenging, the high-temperature combustion gases exiting the cylinder are pushed out through the outlet along with the lower-temperature scavenging air. During scavenging, the scavenging air and combustion gases are mixed. Nevertheless, because the concentration of combustion gases is initially higher and decreases over time during the discharge phase, the exhaust gases exhibit a temperature gradient over time.

[0016] In other words, the gas guided through the outlet is separated into a first portion of exhaust gas that is relatively high temperature (i.e., mostly combustion gas) and a second portion of exhaust gas that is relatively low temperature (i.e., mostly intake air). The first portion of exhaust gas contains most of the particulate matter emissions and nitrogen oxides.

[0017] The engine may include a turbocharger. This turbocharger may be placed in the first and / or second component exhaust line. The turbocharger may be placed downstream of the particulate matter reduction device. The turbocharger may be placed downstream of the first and / or second SCR. In an alternative embodiment, the turbocharger may be placed upstream of the second SCR.

[0018] The separation device may also be formed with one or more valves positioned in front of the exhaust gas receiving section. Preferably, the separation device includes at least one, particularly two, valve per combustion chamber. The valve(s) may be butterfly valve(s), poppet valve(s), or other suitable valve(s). The separation device may also be positioned behind the exhaust gas receiving section and in front of or behind the turbocharger. The separation device may be formed with a plurality of valves.

[0019] In one embodiment, the separation device includes a controllable valve for opening and closing a first component exhaust line to separate the exhaust gas into the first and second component exhaust streams. This controllable valve may be controlled by a controller. The controller may be mechanical, i.e., a camshaft of the engine, or electronic.

[0020] The separation device is configured to separate the exhaust gas from the combustion chamber into first and second gas streams for the first and second component exhaust lines, respectively, and the gas streams are discharged in sequence.

[0021] Another embodiment of the separation device provides simple and reliable separation of the first and second exhaust gas streams.

[0022] The separation device can separate the first part of the exhaust gas, which is discharged first with relatively more combustion gas and therefore a higher temperature, from the part discharged later with relatively more intake air and a lower temperature.

[0023] In one embodiment, when scavenging air flows through the outlet, the controllable valve is first opened during the discharge phase of the combustion chamber and then closed later. One embodiment of such a separation device is shown in European patent application EP 2 151 569 A1.

[0024] The separation device is configured to separate exhaust gas from a combustion chamber into a first gas stream that is relatively high temperature and a second gas stream that is relatively low temperature. Preferably, the relatively high temperature gas stream is for the first component exhaust line. Preferably, the relatively low temperature gas stream is for the second component exhaust line.

[0025] In other words, the separation device is configured to separate the exhaust gas from the combustion chamber into, preferably, a first gas stream for a first component exhaust line and, preferably, a second gas stream for a second component exhaust line, wherein the temperature of the second gas stream is lower than the temperature of the first gas stream.

[0026] The separation device can separate the first gas stream by determining the timing of opening and closing valves for the first and second component exhaust lines. In one embodiment, the separation device is configured to guide a first portion that is first discharged from the outlet through the first component exhaust line and a second portion that is subsequently discharged through the second component exhaust line.

[0027] The separation device may be configured to set a valve that allows flow into the first component exhaust line and the second component exhaust line depending on the temperature, crank angle, time, or pressure inside the cylinder of the exhaust gas leaving the cylinder.

[0028] Typically, during the first stage of exhaust gas discharge, the temperature of the exhaust gas rises rapidly to a maximum, just like the pressure inside the cylinder, and then slowly decreases.

[0029] During the second stage, at a specific point in time (t s ) or a specific crank angle (α s Starting from ), when scavenging air enters the cylinder, the pressure inside the cylinder becomes a specific pressure (p s It is lower than ), and the temperature of the emitted exhaust gas is a specific temperature (T s It has a lower temperature than ). During the second stage, the temperature of the exhaust gas can drop, for example, below 350°C, and especially below 250°C.

[0030] An internal combustion engine may include sensors for detecting values ​​that allow conclusions to be drawn regarding the temperature of the exhaust gas in the cylinder, such as temperature sensors, pressure sensors, time sensors, or crank angle sensors. The sensors are preferably high-speed and / or rapid measurement sensors that respond quickly, so that the measured values ​​and changes in the measured values ​​are detected sufficiently quickly during the combustion cycle. Due to the rapid measurement, continuous comparison with a predetermined reference and / or timely change of the settings of the separation device become possible.

[0031] The value can be compared with a predetermined specific value. When the specific value is reached, the separation device can be changed to a new condition, for example, from a first condition in which the exhaust gas is guided into the first component exhaust line rather than the second component exhaust line, to a second condition in which the exhaust gas is guided into the second component exhaust line rather than the first component exhaust line.

[0032] An internal combustion engine may include a control unit for operating a separation device, particularly for setting a valve, according to a value that enables drawing conclusions about the sensor's measurement and / or temperature and / or the temperature of the exhaust gas, such as pressure, time, or crank angle. A specific value, such as a specific temperature (T s ), specific pressure (p s ), at a specific point in time (t s ) or a specific crank angle (α s As soon as ) is reached, the control unit can change the settings of the separation device.

[0033] A specific value is predetermined and can be provided to or stored in the control unit.

[0034] A specific value may be dependent on the load. A map having a load-dependent specific value may be arranged for use by the control unit.

[0035] The control unit may be suitable for receiving and / or reading and / or storing a predetermined value.

[0036] The control unit may be suitable for comparing the obtained value with a predetermined value.

[0037] A control unit for setting a separation device, particularly a valve, may be configured to operate the separation device according to the load. For a predetermined load range, the control unit may set the separation device as described above.

[0038] Therefore, only exhaust gases with a temperature higher than a specific threshold enter the particulate matter reduction device.

[0039] The first high-temperature portion of the exhaust gas has a relatively high concentration of particulate matter, whereas the first low-temperature portion is relatively clean.

[0040] A higher overall temperature of the exhaust gas flowing through the particulate matter reduction device increases the potential for oxidation of unburned particulate components. This is particularly advantageous in the case of low engine loads, where the temperature of at least a portion of the exhaust gas is too low for the oxidation reaction of particulate matter.

[0041] Typically, at higher loads, if the average temperature of the exhaust gas is relatively high, more exhaust gas can be guided through the first component exhaust line than at lower loads.

[0042] Additionally or alternatively, there may be a predetermined load range in which only the first gas stream for the first component exhaust line, only the second gas stream for the second component exhaust line, or the first and second gas streams for the first and second component exhaust lines simultaneously are allowed.

[0043] The engine may include exhaust gas recirculation (EGR). The EGR may be connected to the inlet and outlet of the internal combustion chamber.

[0044] In one embodiment, the engine includes an exhaust gas receiving section for collecting exhaust gases from the cylinders. A separation device may be positioned upstream of the exhaust gas receiving section. Thus, the exhaust gases may be separated before the components of the exhaust gas stream (e.g., combustion gases and scavenging air) are homogeneously mixed in the exhaust gas receiving section.

[0045] The exhaust gas receiving section can be placed in the second component exhaust line.

[0046] The separation device can be placed downstream of the exhaust gas receiving section.

[0047] In one preferred embodiment, at least one, preferably each separation device includes a plurality of valves. The separation device may include two or four valves. In one embodiment, two of the four valves are used to divert the first component exhaust stream into the second component exhaust line. The other two valves are used to divert the second component exhaust stream into the second component exhaust line.

[0048] In a further preferred embodiment, one of three or four or more valves is suitable for diverting a first portion of the exhaust gas into a first component exhaust stream. The other two or three or more valves are suitable for diverting the exhaust gas into a second component exhaust line. Thus, the first and second component exhaust streams can be generated particularly simply and efficiently.

[0049] In one embodiment, the separation device is formed with outlet valves for each of at least two cylinders. In one example, each cylinder may include a plurality of outlet valves. A first outlet valve of each cylinder is suited to open a first component exhaust line, and a second outlet valve is suited to open a second component exhaust line. In another example, each cylinder includes two valves for each component exhaust line. Additionally, each outlet may include four outlet valves. In these preferred embodiments, the separation device is formed with outlet valves, and a compact device is provided.

[0050] Additionally or alternatively, the separation device may include one or two or four or more valves, such as butterfly valves, downstream of the outlet or outlet valve.

[0051] In one embodiment, the engine includes an SCR reactor, and the reactor may be positioned in a second component exhaust line. The second component exhaust line may be positioned downstream of the exhaust gas receiving section.

[0052] Preferably, a device for spraying a reducing agent, such as a urea solution, is placed upstream of the SCR reactor.

[0053] The second SCR reactor placed in the second component exhaust line can have a larger maximum capacity than the first SCR reactor placed in the first component exhaust line.

[0054] In one embodiment, the second component exhaust line preferably comprises an SCR tube and a bypass tube parallel to each other. A second SCR reactor may be disposed in the SCR tube. The second component exhaust line comprises at least one, preferably two, valves for guiding exhaust gas into the SCR reactor and / or the bypass tube. Additionally, the engine may include a controller that operates the valves to send exhaust gas to the second SCR reactor, through the bypass tube, or through both.

[0055] The bypass pipe enables a fuel-efficient operating mode of the engine. Accordingly, depending on the desired operating mode—that is, an operating mode that is fuel-efficient or reduces emissions at high or low loads—the operator can select which pipe / component exhaust line to send the exhaust gases through. Examples of operating modes are described with respect to the embodiments shown in the present invention.

[0056] In one embodiment, the first component exhaust line includes a heating element positioned upstream of the particulate matter reduction device.

[0057] The particulate matter reduction device itself may include or be connected to a heating device that heats the exhaust gas to a temperature sufficient for thermal regeneration.

[0058] A sufficient temperature (minimum continuous operating temperature) for reducing particulate matter, especially for thermal regeneration, can be 500°C.

[0059] Another aspect of the present invention relates to a method for reducing particulate matter emissions from an internal combustion engine. Preferably, the engine is an internal combustion engine as described above. The method comprises the following steps:

[0060] - A step of burning fuel in at least two cylinders having internal combustion chambers - said combustion chambers have an exhaust gas outlet having fuel inlet and outlet valves -;

[0061] - A step of discharging exhaust gas through the above outlet;

[0062] - A step of separating the exhaust gas of all combustion chambers into first and second exhaust gas streams downstream of the combustion chamber using a separation device - the first exhaust gas stream is delivered by a first component exhaust line, and the second exhaust gas stream is delivered by a second component exhaust line, and both exhaust lines are connected to at least one separation device -;

[0063] - A step of guiding a first exhaust gas stream within a first component exhaust line to a particulate matter reduction device;

[0064] - A step of guiding a second exhaust gas stream within a second component exhaust line - the first and second exhaust lines are maintained separately from each other at least up to a particulate matter reduction device -; and

[0065] - A step of reacting the first exhaust gas stream in a particulate matter reduction device so as to reduce the amount of particulate matter in the first exhaust gas stream.

[0066] A first exhaust gas stream may be discharged during the first stage of a combustion cycle, and a second exhaust gas stream may be discharged during the second stage of a combustion cycle. The first exhaust gas stream has a first temperature, and the second exhaust gas stream has a second temperature, and the second temperature is lower than the first temperature.

[0067] The first exhaust gas stream preferably has a temperature sufficient for the thermal regeneration of the particulate matter reduction device.

[0068] Additionally, a first SCR reactor having a maximum capacity of 80% or less of the full-load outflow of at least two cylinders, preferably 60% or 50% or less, may be placed in the first component exhaust line.

[0069] In a preferred embodiment of the present method, the present method further includes the step of heating the first exhaust gas stream upstream of the particulate matter reduction device.

[0070] The first portion discharged from the internal combustion chamber is guided into the first component exhaust line, and the subsequent portion is guided into the second component exhaust line. The first portion discharged has a higher temperature than the later portion (the second portion). Thus, a simple method is provided for separating exhaust gases into a relatively high-temperature exhaust stream and a relatively low-temperature exhaust stream.

[0071] An internal combustion engine may include a fresh air supply unit, which is intended to guide fresh air into the cylinder through a scavenging air receiving unit and a flushing hole (also called a scavenging port or inlet port). Fresh air may be used to flush combustion gases out of the cylinder at the end of the combustion cycle. During the combustion cycle, there is a first stage in which mainly combustion gases are discharged, and a second stage in which a mixture of combustion gases and fresh scavenging air is discharged. The exhaust gases discharged during the first stage may be guided from a first component exhaust line as a first gas stream. The exhaust gases discharged during the second stage may be guided from a second component exhaust line as a second gas stream.

[0072] The first gas stream, primarily containing combustion gases, is generally at a higher temperature than the exhaust gas mixture (usually discharged from the cylinder), which contains combustion gases and fresh scavenging air. Additionally, the exhaust gases discharged during the first stage contain higher concentrations of particulate matter and high NO. x It has a content. Since the second gas stream contains a mixture of combustion air and fresh air, it generally has a lower concentration of particulate matter and NO than the first gas stream. x It has a content.

[0073] The ratio of combustion gas and / or the concentration of particulate matter in the second gas stream may be low, so there is no need to guide the second gas stream through a particulate matter reduction device.

[0074] The temperature of the exhaust gas can be maintained above the critical temperature during the total emission period, so that nearly all or all of the exhaust gas is guided through the first component exhaust line to the particulate matter reduction device. The exhaust gas can be guided through the particulate matter reduction device during the total emission period. In this case, the second exhaust gas stream can have a value close to or equal to zero liters / second.

[0075] The first exhaust gas stream is relatively high temperature and the second exhaust gas stream is relatively low temperature. As mentioned here, relatively high temperature is compared to other exhaust gas streams. For example, the first exhaust gas stream, which is relatively high temperature, means that it is hotter than the second exhaust gas stream.

[0076] In a preferred embodiment, the method further comprises the step of partially or completely guiding a second exhaust gas stream through a bypass pipe without partially or completely reacting the second component gas stream. In a preferred embodiment, the second exhaust gas stream and / or the first exhaust gas stream are sent to a turbocharger.

[0077] In one embodiment, the first and / or second streams are guided in parallel to the turbocharger.

[0078] In a further embodiment of the present invention, an internal combustion engine is provided. The internal combustion engine is preferably a two-stroke engine. The engine is particularly suitable for a propulsion system, such as a propulsion system for a ship. The internal combustion engine comprises at least two cylinders. Each of the two cylinders comprises a combustion chamber and also has an exhaust gas outlet having fuel inlet and outlet valves. The internal combustion engine comprises at least one separator downstream of the combustion chamber. First and second exhaust lines are connected to at least one separator. The at least one separator is configured to separate the exhaust gas from each combustion chamber into, for example, a first gas stream for a first component exhaust line and, for example, a second gas stream for a second component exhaust line, wherein the temperature of the second gas stream is lower than the temperature of the first gas stream.

[0079] A first SCR reactor may be placed in the first component exhaust line and / or a second SCR reactor may be placed in the second component exhaust line.

[0080] The separation device may be configured to guide high-temperature exhaust gas into the first and / or second component exhaust line and pass through the first and / or second SCR reactor.

[0081] By introducing a gas having a temperature higher than 500℃, the SCR catalyst is regenerated.

[0082] Therefore, the separation device enables the regeneration of the selected SCR reactor by selecting each first or second component exhaust line to guide the high-temperature exhaust gas.

[0083] The separation device enables the regeneration of the SCR reactor even at low loads when only the first portion of the exhaust gas, mainly containing combustion gas, has a sufficient temperature for regeneration.

[0084] With reference to the attached drawings, non-limiting embodiments of the present invention are described merely as examples. Brief explanation of the drawing

[0085] FIG. 1 shows a schematic diagram of a first embodiment according to the present invention. FIG. 2 shows a schematic diagram of a second embodiment according to the present invention. FIG. 3 shows a schematic diagram of a third embodiment according to the present invention. Specific details for implementing the invention

[0086] FIG. 1 shows a schematic diagram of a first embodiment according to the present invention. An internal combustion engine (1) includes a cylinder (2) having a combustion chamber (3). Inside the combustion chamber (3), a piston (26) having a piston rod (25) is provided.

[0087] Fuel is guided into the combustion chamber (3) through a fuel inlet (not shown) and is burned inside the combustion chamber (3). The combustion gas is guided through an outlet (5) containing a single outlet valve (6). The combustion gas is scavenged with scavenge air. Behind the outlet valve (6), the combustion gas and scavenge air (commonly referred to as exhaust gas) are guided through an outlet pipe (29).

[0088] The outlet pipe (29) includes two channels. The first channel is used to send a portion of the exhaust gas through the particulate matter reduction device (10). The second channel is used to guide the remainder of the exhaust gas to the exhaust gas receiving section (11).

[0089] A separation device (7) is placed in the outlet pipe (29). The separation pipe (7) includes two valves (7a, 7b) that open and close two channels of the outlet pipe (29).

[0090] The combustion machine (1) includes a control unit (32), so the separation device (7) is configured to separate the exhaust gas from the combustion chamber (3) into a first gas stream for a first component exhaust line (8) and a second gas stream for a second component exhaust line (9), and the temperature of the second gas stream is lower than the temperature of the first gas stream.

[0091] The combustion machine (1) includes a sensor (33) (in this case, a temperature sensor) for detecting a value that allows a conclusion to be drawn about the temperature of the exhaust gas.

[0092] When the temperature of the exhaust gas drops below a predetermined value, the control unit (32) opens the valve (7a) and closes the valve (7b) as shown in the figure.

[0093] When the temperature of the exhaust gas is sufficiently high, the control unit (32) keeps the valve (7a) in a closed state and keeps the valve (7b) in an open state, so that the exhaust gas stream is guided through the particulate matter reduction device (10) and enables thermal regeneration.

[0094] FIG. 2 shows a schematic diagram of a second embodiment of a two-stroke crosshead internal combustion engine (1). This engine (1) includes a part of the engine of FIG. 3.

[0095] A first component exhaust line (8) is connected to an outlet pipe (29). The connected first component exhaust line (8) guides a portion of the exhaust gas through the outlet (5) to a particulate matter reduction device (10) and then to a first SCR reactor (28). The first SCR reactor (28) reduces nitrogen oxides in the exhaust gas by selective catalytic reduction.

[0096] The reduction of nitrogen oxides is based on the reaction between nitrogen oxides and ammonia. Ammonia is produced by injecting urea into a urea injector (21) upstream of the first SCR reactor (28). Only a portion of the exhaust gas from the cylinder (2) is guided through the first component exhaust line (8). The exhaust gas released from the cylinder may have a temperature too low (e.g., less than 400°C) for thermal regeneration of the particulate matter reduction device (10). In any case, to enable thermal regeneration, the line (8) may additionally include a heating element (16), which may be placed upstream of the particulate matter reduction device (10) and the first SCR reactor (28) and also downstream of the urea injector (21).

[0097] In a two-stroke engine (1), scavenging air is used during the exhaust phase to expel combustion gases from the combustion chamber (3). Thus, the exhaust gas contains both combustion gases and scavenging air. The combustion gases have a higher temperature than the scavenging air due to combustion. Additionally, the concentration of nitrogen oxides and particulate matter is higher in the combustion gases than in the scavenging air.

[0098] When combustion gas and scavenging air are mixed in an exhaust gas receiving section (11), such as an exhaust gas manifold, the temperature of the combustion gas is reduced. At low loads, this temperature is particularly low because the fuel injection is small, the amount of combustion gas is low, and the particulate matter reduction device cannot be thermally regenerated.

[0099] Accordingly, at a low load, the combustion gas can be separated from the intake air at the outlet (5) of the cylinder (2). The first separation method is to open the exhaust line (8) by closing the valve of the separation device (7) for the second component exhaust line (9). In this configuration, the exhaust gas is guided entirely through the first component exhaust line (8). At a higher load, both valves (e.g., butterfly valves) of the separation device (7) are opened, and most of the exhaust gas is guided through the second component exhaust line (9).

[0100] Unlike the engine shown in FIG. 1, the engine shown in FIG. 2 includes two outlet valves (6) for the combustion chamber (3). Although two outlet valves are shown, preferably one or four valves are used.

[0101] The outlet valve (6) is used to guide exhaust gas. First, when combustion gas is being discharged, the outlet valve for the first component exhaust line (8) is opened and the outlet valve for the second component exhaust line (9) is closed. In this configuration, exhaust gas can be guided through the first component exhaust line (8). This can be aided by closing both butterfly valves of the separation device (7). As soon as the scavenging air reaches the outlet (5), the outlet valve (6) for the first component exhaust line (8) is closed and the outlet valve for the second component exhaust line (9) is opened.

[0102] Thus, the separated portion is guided through the first component exhaust line (8), thereby enabling reliable reduction of particulate matter in the particulate matter reduction device and reliable reduction of nitrogen oxides in the first SCR reactor (28). Additionally, since only a portion of the exhaust gas is guided through the line (8), a small SCR reactor can be used. An SCR reactor (28) with a maximum capacity of 40% of the full load outflow is sufficient, and thus space is saved. The particulate matter reduction device (10) may include a reactor controller (27) to further control the temperature inside the reactor.

[0103] The second component exhaust line (9) is connected to the exhaust gas receiving section (11). From this exhaust gas receiving section (11), the exhaust gas passes through the SCR pipe (13) or the bypass pipe (14). Each of the SCR pipe (13) and the bypass pipe (14) includes a valve (15). This valve (15) can be opened and closed independently to allow the bypass pipe (14) and / or the SCR pipe (13) to be used. The SCR pipe (13) includes a second SCR reactor (12). The second SCR reactor (12) is configured for a higher throughput than the first SCR reactor (28). The second SCR reactor (12) has a maximum capacity of at least 60% of the full-load outflow of the cylinder (2).

[0104] The element injector (36) is positioned upstream of the second SCR reactor (12).

[0105] In one embodiment, the second SCR reactor (12) and the first SCR reactor (28) may have a combined total capacity of at least 100% of the full-load outflow of at least two cylinders. The bypass pipe may not include an SCR.

[0106] Additionally, the SCR tube (13) includes a second valve (20) downstream of the SCR reactor (12). The valve (20) prevents backflow into the SCR tube (13).

[0107] The first line (8) and the second line (9) (i.e., bypass pipe (14) and SCR pipe (13)) are connected to a turbocharger (17) and a funnel (30) (see FIG. 3) behind it. The turbocharger (17) draws in fresh air using energy stored in the exhaust gas. The fresh air drawn in by the turbocharger (17) passes through a cooler system (19) and a fresh air supply unit (18) and is guided to an inlet (4). Behind the inlet (4), the fresh air passes through a scavenging air receiving section (23) and a flushing hole (31) and is guided into a cylinder (2).

[0108] In addition to the reduction of nitrogen oxides in the SCR reactor (28, 12), emissions such as particles and sulfuric acid are reduced to an EGR cleaner (24). An EGR pipe (22) is connected to the outlet (5) of the cylinder (2). The EGR pipe (22) guides the exhaust gas to the EGR cleaner (24) and also guides it into the combustion chamber (3) after the EGR cleaner (24). The EGR cleaner (24) may include a scrubber, a cooler, and a water mist capturer.

[0109] The engine (1) as shown in Fig. 1 enables different operating modes.

[0110] The first operating mode is particularly suitable for low loads. At low loads, the valve (15) and the separation device (7) are set so that the first component exhaust line (8) and the bypass pipe (14) are open. The SCR pipe (13) is closed. A first portion of the exhaust gas containing combustion gas is guided through the particulate matter reduction device (10) and the first SCR reactor (28), where nitrogen oxides are reduced. The remainder of the exhaust gas (containing mainly scavenging air) is guided through the bypass pipe (14). In particular, the SCR reactor (28) may be bypassed by a separate bypass line (not shown).

[0111] In the second operating mode, exhaust gas is guided only through the second exhaust line (9), and exhaust gas is not guided through the first exhaust line (8). In one variation of the second operating mode, exhaust gas is guided through the SCR pipe (13) and the second SCR reactor (12). The second operating mode corresponds to an SCR reactor in an engine known in the prior art.

[0112] In the third operating mode, exhaust gas is guided only through the bypass pipe (14), and the first component exhaust line (8) and the SCR pipe (13) are closed. In this operating mode, the particulate matter reduction device (10) and the SCR (28, 12) are switched off.

[0113] FIG. 3 shows a third embodiment of an internal combustion engine (1). The third embodiment of the engine (1) is similar to the second embodiment. Consequently, reference numbers indicate similar parts. However, unlike the second embodiment, the SCR pipe (13) and bypass pipe (14) containing the second SCR reactor (12) are positioned downstream of the turbocharger (17).

[0114] The engine (1) includes a cylinder (2). At the outlet of the cylinder (2), the exhaust gas from the cylinder (2) is separated into first and second streams. The first stream is guided through a first component exhaust line (8), and the second stream is guided through a second component exhaust line (9). The second component exhaust line (9) includes an exhaust gas receiving section (11). The first component exhaust line (8) is configured as shown with reference to FIG. 2 and includes a particulate matter reduction device (10) and a first SCR reactor (28), and is also parallel to the exhaust gas receiving section (11). After the first SCR reactor (28) and before the second SCR reactor (12) and the bypass pipe (14), the first component exhaust line (8) is combined with the second line (9), and the entire exhaust gas from all cylinders (2) is guided through a turbocharger (17).

[0115] After the turbocharger (17), the exhaust gas is guided by the second component exhaust line (9) into the second SCR reactor (12) through the SCR pipe (13) or bypass pipe (14). Then, the exhaust gas is discharged through the funnel (30). In one variation, the second SCR reactor (12) and the bypass pipe (14) may be positioned upstream of the turbocharger (17).

[0116] The operating mode schematically described above for FIG. 2 can also be used in the embodiment shown in FIG. 3.

Claims

Claim 1 An internal combustion engine comprises at least two cylinders (2), each cylinder comprises a combustion chamber (3), and the combustion chamber has an exhaust gas outlet (5) having fuel inlet and outlet valves (6); the internal combustion engine comprises at least one separation device (7) downstream of the combustion chamber (3), and a first component exhaust line (8) and a second component exhaust line (9) are connected to the at least one separation device (7); the at least one separation device (7) is configured to separate exhaust gas from each combustion chamber (3) into a first gas stream for the first component exhaust line (8) and a second gas stream for the second component exhaust line (9); a particulate matter reduction device (10) is disposed on the first component exhaust line (8) downstream of the separation device (7); the first component exhaust line (8) and the second component exhaust line (9) are separate from each other at least up to the particulate matter reduction device (10); and An internal combustion engine comprises a control unit (32) for operating the separation device according to a value that allows a conclusion to be drawn regarding the temperature of the exhaust gas, and the separation device (7) is configured to separate the exhaust gas from the combustion chamber (3) into a first gas stream discharged during the first stage of the combustion cycle for the first component exhaust line (8), and a second gas stream discharged during the second stage of the combustion cycle for the second component exhaust line (9), wherein the temperature of the second gas stream is lower than the temperature of the first gas stream, so that only the exhaust gas having a temperature higher than a specific threshold value enters the particulate matter reduction device. Claim 2 In claim 1, the separation device (7) comprises a controllable valve for opening and closing a first component exhaust line to separate exhaust gas into first and second gas streams, an internal combustion engine. Claim 3 In claim 1, the internal combustion engine includes an exhaust gas receiving section (11) for collecting exhaust gas from a cylinder, and the at least one separation device (7) is positioned upstream of the exhaust gas receiving section (11). Claim 4 In claim 1, the separation device (7) is formed by an outlet valve of at least two cylinders (1), in an internal combustion engine. Claim 5 An internal combustion engine according to claim 1, wherein at least one separation device (7) comprises a plurality of valves for each combustion chamber (3) to separate exhaust gas into the first and second gas streams. Claim 6 In claim 1, the internal combustion engine comprises a sensor for detecting a value that enables a conclusion to be drawn regarding the temperature of the exhaust gas in the cylinder. Claim 7 In claim 1, the internal combustion engine (1) comprises at least one SCR reactor (12), and the SCR reactor (12) is disposed in a second component exhaust line (9). Claim 8 In claim 1, the first component exhaust line (8) comprises a heating element (16) disposed upstream of the particulate matter reduction device (10), in an internal combustion engine. Claim 9 An internal combustion engine according to claim 1, wherein the second component exhaust line comprises an SCR pipe (13) and a bypass pipe (14), an SCR reactor (12) is disposed in the SCR pipe, and the second component exhaust line comprises at least one valve (15) for guiding exhaust gas into the SCR reactor (12) and / or the bypass pipe (14). Claim 10 In claim 9, an internal combustion engine in which a device for injecting a reducing agent is positioned upstream of the SCR reactor. Claim 11 A method for reducing particulate emissions and also thermally regenerating a particulate matter reduction device of an internal combustion engine, comprising the step of burning fuel in at least two cylinders (2) having a combustion chamber (3), wherein the combustion chamber (3) has an exhaust gas outlet (5) having a fuel inlet and outlet valve (6); and the step of discharging exhaust gas through the exhaust gas outlet (5). A step of operating at least one separation device (7) according to a value that enables a conclusion regarding the temperature of the exhaust gas, wherein a first exhaust gas stream discharged during the first stage of the combustion cycle is delivered by a first component exhaust line (8), and a second exhaust gas stream discharged during the second stage of the combustion cycle is delivered by a second component exhaust line (9), and both exhaust lines (8, 9) are connected to the at least one separation device (7); a step of guiding the first exhaust gas stream within the first component exhaust line (8) to a particulate matter reduction device (10); a step of guiding the second exhaust gas stream within the second component exhaust line (9), wherein the first and second component exhaust lines are maintained separately from each other at least up to the particulate matter reduction device (10), the first exhaust gas stream has a first temperature and the second exhaust gas stream has a second temperature, and the A method comprising: a step of guiding a second exhaust gas stream such that the temperature is lower than the first temperature, and only exhaust gas having a temperature higher than a specific threshold value enters the particulate matter reduction device; and a step of purifying the first exhaust gas stream in the particulate matter reduction device so that the amount of particulate matter is reduced. Claim 12 In claim 11, the portion first discharged from the combustion chamber during the separation step is guided into the first component exhaust line (8), and the portion subsequently discharged is guided into the second component exhaust line (9). Claim 13 A method according to claim 11, further comprising the step of heating a first exhaust gas stream upstream of a particulate matter reduction device (10) to thermally regenerate the particulate matter reduction device (10). Claim 14 A method according to claim 11 further comprising the steps of: guiding the second exhaust gas stream to an SCR reactor (12) through a second component exhaust line (9); and reacting the second exhaust gas stream in the SCR reactor (12). Claim 15 In claim 14, a method in which a reducing agent is injected upstream of the SCR reactor. Claim 16 A method according to claim 11, comprising the steps of detecting a value that enables a conclusion regarding the temperature of the exhaust gas in the cylinder, and operating the separation device according to the detected value. Claim 17 delete

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