DE102012013249A1 - Self-ignition internal combustion engine i.e. turbocharged self-ignition diesel engine, for motor vehicle, has control device for differently adjusting reference value for different modes and within mode of engine - Google Patents

Abstract

The engine (1) has a cooling (3) for controlling temperature of raw air, where a charge air feed line (21), two flow paths (22) and a combustion air feed line (24) sucks the raw air with a temperature and supplies combustion air with another temperature to a combustion chamber (18). The cooling device adjusts the latter temperature of the combustion air in the charge air feed line, the flow paths and the combustion air feed line to a reference value. A control device (80) differently adjusts the reference value for different modes and within a mode of the engine. The cooling device is designed as a raw air-air heat exchanger device, a raw air-water heat exchanger device and a raw air-cooled exhaust-gas heat exchanger device. An independent claim is also included for a method for operating a self-ignition internal combustion engine.

Description

The present invention relates to a self-igniting internal combustion engine with intake air temperature control and a method for operating an internal combustion engine.

In supercharged self-igniting internal combustion engines (diesel engines), it is currently state of the art that during their operation unfiltered air, which compresses by means of an exhaust gas turbocharger (more precisely by means of a compressor wheel of an exhaust gas turbocharger) in an intake tract of the internal combustion engine and the compressed raw air then by means of a heat exchanger device, often an air Air-heat exchanger device (charge air cooler, LLK) is cooled as much as possible in order to supply the combustion chamber as large an amount of air as possible.

Furthermore, to improve the quality of the exhaust gas, at least part of the exhaust gas is returned from the combustion chamber into the intake tract, where it is mixed with the cooled raw air and the resulting combustion air is supplied to the combustion chamber. The recirculated exhaust gas is usually subjected to cooling as well.

By the cooling of raw air and recirculated exhaust gas there is a risk of deposition of exhaust gas components in the intake. Against this background describes the DE 10 2006 057 488 A1 , a method for operating an internal combustion engine and an internal combustion engine, wherein the exhaust gas generated by the internal combustion engine via an exhaust gas recirculation device, which comprises at least two cooling devices, each associated with a bypass is fed back to the internal combustion engine, which exhaust depending on the load state of the internal combustion engine in the exhaust gas recirculation device is cooled, wherein fresh air via a charge air, which at least one cooling device and at least one of the cooling device connected in parallel bypass, the internal combustion engine is supplied, which fresh air is guided depending on the operating state (load condition) on the cooling device or the bypass.

Furthermore, from the prior art methods and devices for adjusting the temperature of the intake air for internal combustion engines are known.

For example, describes the DE 32 43 016 A1 a method for controlling the temperature of the intake air for internal combustion engines, in which by mixing cold and preheated air in a Ansaugkanalsystem using a depending on the temperature of the mixed air electrically adjustable control valve in response to a predetermined mixed air temperature tolerance and the maximum adjustment of the control valve electrical signals are generated according to a certain arbitrarily specifiable education law, which are used for electromotive adjustment of the control valve. The adjustment of the control flap is carried out such that the relevant electric motor is de-energized at each rest position of the control valve. The motor is also without power when the control flap is fully open or closed.

And from the DE 42 22 041 A1 is a mixing valve for hot and cold intake air of an internal combustion engine with separate rotary vane segments for a cold and a hot air duct known in which the respective occlusive circumferential surface of each of the rotary valve segments on a non-coaxial with each of the pivot axis lateral surface is due to the coaxial offset each in The rotational opening direction of the segment edge located at the front has a greater radial distance than the segment edge located in this direction of rotation, and the edges of the openings of the channels lie on a lateral surface coaxial with the closure surfaces of the rotary valve segments located in the closed position.

In addition, the describes DE 199 26 135 A1 an air intake system for an internal combustion engine having an air filter, which has in a air filter housing a raw air space, connected to the internal combustion engine clean air space and arranged between the raw air space and clean air chamber filter cartridge. The raw air space is subdivided by means of a separation into a raw air inlet volume and a raw air outlet volume, wherein a passage cross section for raw air at the separation from the raw air inlet volume into the raw air outlet volume is variable.

The object of the present invention is to provide a self-igniting internal combustion engine which is improved in comparison with the prior art and an improved method for operating a self-igniting internal combustion engine. These objects are achieved by the internal combustion engine according to claim 1 and the method according to claim 8. Advantageous developments of the invention are subject of the dependent claims.

The self-igniting internal combustion engine according to the invention has an intake tract which sucks a raw air having a first temperature and which supplies a combustion air having at least one combustion chamber to at least one combustion chamber for adjusting the temperature of the combustion air to a desired value in the intake tract Temperature control of the raw air is provided. The self-igniting internal combustion engine according to the invention is characterized in that it comprises a control device with which the desired value for different operating modes and / or within an operating mode of the internal combustion engine is set differently.

The self-igniting internal combustion engine according to the invention has the advantage that the temperature of the combustion air, which is passed into the combustion chamber, is set and possibly regulated as a function of the respective operating mode and / or within one operating mode, ie the temperature of the combustion air serves as a controlled variable. In contrast, according to the prior art, the temperature of the combustion air is not adapted to the respective operating mode, but rather serve injection parameters as a controlled variable, which must be changed depending on the operating mode and combustion air temperature.

Thus, according to the invention, for example, the air supplied for the combustion of fuel is available within a narrow combustion air temperature range, so that optimum combustion of fuel is ensured even under unfavorable environmental conditions.

According to a first advantageous embodiment of the invention, the self-igniting internal combustion engine according to the invention as at least one device for controlling the raw air a raw air-air heat exchanger device, raw air-water heat exchanger device and / or raw air-cooled exhaust heat exchanger device, whereby the temperature of raw air are lowered can.

According to a second advantageous development of the invention, the self-igniting internal combustion engine is characterized in that the at least one device for tempering the unfiltered air has an electric air heater, a raw air coolant heat exchanger device and / or raw air uncooled exhaust gas heat exchanger device, whereby the temperature of unfiltered air increases can be.

It is also advantageous if the self-igniting internal combustion engine has at least one adjustable bypass device for the at least partial bypassing of unfiltered air to the at least one device for controlling the temperature of the untreated air.

It is also advantageous if the self-igniting internal combustion engine has at least one exhaust gas recirculation device for returning at least part of the exhaust gas generated by the internal combustion engine, wherein the at least one exhaust gas recirculation device at least one device for cooling the exhaust gas and at least one adjustable bypass device for at least partially bypassing exhaust gas having at least one device for cooling the exhaust gas.

According to yet another advantageous development of the invention, the self-igniting internal combustion engine is characterized in that, by means of the control device, the desired value of the combustion air is adjusted to a temperature in the range between 30 ° C and 150 ° C, depending on the operating mode and / or within one operating mode. By the control device can be set to a temperature in the range of 90 ° C to 150 ° C, and / or for a normal operating mode to a temperature in the range of 30 ° C to 70 ° C in a particularly advantageous manner, the setpoint for a regeneration phase of a diesel particulate filter become. Further examples of an operating mode in which the desired value of the combustion air can advantageously be set and optionally regulated according to the invention are a catalyst desulphurisation (exhaust gas temperature in the range from about 400 ° C. to 500 ° C.), the storage operation of an NO _x storage catalytic converter (LNT) (at a catalyst temperature of up to about 300 ° C, for example from about 150 ° C to 250 ° C) and the regeneration operation of a NO _x storage catalyst (at a catalyst temperature greater than 300 ° C, for example about 400 ° C to 500 ° C).

The present invention also encompasses a method for operating a self-igniting internal combustion engine in which a raw air having a first temperature is drawn in via an intake tract and a combustion air having a second temperature is supplied to at least one combustion chamber, wherein the temperature of the combustion air is set to a desired value in the intake tract at least one device for controlling the temperature of the raw air is provided. The method according to the invention is characterized in that the desired value for different operating modes and / or within an operating mode of the internal combustion engine is set differently by means of a control device.

Advantageously, in the method by means of the control device, the desired value can be set to a temperature in the range between 30 ° C. and 150 ° C., depending on the operating mode and / or within one operating mode, in a particularly preferred manner for a regeneration phase of a diesel particulate filter to a temperature in Range from 90 ° C to 150 ° C, and / or for a normal operating mode to a temperature in the range of 30 ° C to 70 ° C.

The present invention will be explained in more detail with reference to the accompanying drawings.

It shows purely schematically:

1 A first embodiment of a self-igniting internal combustion engine according to the invention;

2 A second embodiment of a self-igniting internal combustion engine according to the invention;

3 A third embodiment of a self-igniting internal combustion engine according to the invention; and

4 A diagram for exemplifying the method according to the invention.

The embodiments described in more detail below represent preferred embodiments of the present invention. The present invention is of course not limited to these embodiments.

Within the figures, the same, functionally identical or functionally similar elements are provided with the same reference numerals.

1 shows a schematic representation of a first embodiment of a self-igniting internal combustion engine according to the invention 1 ,

In the internal combustion engine according to the invention 1 is through an air filter 14 Through unfiltered air at a temperature T0 in the charge air line 21 sucked. In the example shown, the internal combustion engine according to the invention 1 an exhaust gas turbocharger with a turbine 12 and a compressor coupled thereto 13 , The compressor 13 is in the charge air supply line 21 arranged. Through the compressor 13 The sucked raw air is in the charge air supply line 21 directed. The amount of unfiltered raw air is in the example shown by means of an air flow meter 15 (HFM, hot-film air mass meter).

As a device for tempering, ie for adjusting the temperature of the raw air (sucked and / or compressed charge air) is in in 1 shown embodiment within the charge air supply line 21 a first cooling device 3 arranged in the form of a heat exchanger (eg intercooler). Of course, in the charge air supply line 21 more than one means for controlling the temperature of the charge air be present. This can be one or more devices for cooling and / or heating the raw air (charge air). After passing through the unfiltered air through the first means for controlling the temperature of the raw air, this has a temperature T2.

Next is at the in 1 shown embodiment, a throttle valve 6 in the charge air supply line 21 arranged. This throttle 6 is a junction of an exhaust gas recirculation device 7 in a combustion air line 24 upstream.

Through the exhaust gas recirculation device 7 is exhaust gas from an exhaust gas outlet 25 in a first branch line 71 derived. In the first branch line 71 is a second valve 9 provided, which can be adjusted by means of which proportion of the exhaust gas from the exhaust gas discharge 25 branched off and through the exhaust gas recirculation device 7 should be led. Downstream of the second valve 9 is a second cooling device 8th arranged, which is also formed in the example shown in the form of a heat exchanger. As in the first device for tempering 3 also exist with respect to the device for cooling 8th within the exhaust gas recirculation device 7 no particular restrictions and one or more suitable devices may be used.

The second cooling device 8th is a bypass 10 connected in parallel. Are more than a cooling device 8th Of course, there may be more than one adjustable bypass 10 be provided, for example, for each cooling device depending on this one parallel assigned bypass. Downstream of the second cooling device 8th is a third valve 11 arranged. Through the third valve 11 can be adjusted, which portion of the branched exhaust gas through the cooling device 8th or the bypass 10 is directed. Such valve devices can of course be provided for each additional, possibly existing bypass.

By means of a control device 80 becomes a target value for the intake air temperature T3 of the combustion chamber 18 supplied combustion air as a function of the respective operating mode and / or within an operating mode of the internal combustion engine 1 adjusted and, if necessary, regulated. For this purpose, the control device must be suitably equipped with appropriate sensors (eg temperature sensor, air flow meter (s), pressure measuring device (s), rpm measuring device (s), λ probe 26 , etc.) and can receive corresponding data from this sensor. For adjusting / regulating the temperature of unfiltered air, exhaust gas and combustion air, the control device must be capable of depending on the selected operating mode, the existing devices (eg, device for heating and / or cooling of unfiltered air, valves, etc.) accordingly to control or regulate.

For example, at full load and / or during operation at relatively high ambient air temperatures (summer operation), the raw air through the air filter 14 sucked through and through the intercooler 3 be cooled. Depending on the desired target temperature of the given operating mode can now be an optimal proportion of the recirculated exhaust gas using the third valve 11 be passed through the second cooling device. In this way, a different degree of cooling of the recirculated exhaust gas can be achieved and thus also a different intake air temperature T3 of the combustion air supplied to the combustion chamber. Since the intake air temperature T3 of the combustion air also has an influence on the temperature of the exhaust gas formed in the combustion of fuel, the regulation of the intake air temperature T3 can also directly influence the temperature T4 of the exhaust gas in the exhaust gas discharge 25 ,

In 2 is also purely schematically a second example of the internal combustion engine according to the invention 1 shown. In the following description of the second example will be discussed in particular the features in which the internal combustion engine 1 according to the second example differs from that according to the first example.

As with the in 1 shown internal combustion engine 1 will also be at the in 2 shown internal combustion engine 1 through an air filter 14 Through unfiltered air at a temperature T0 in the charge air line 21 sucked. Also identical to the first example also includes the internal combustion engine according to the invention 1 according to the second example, an exhaust gas turbocharger with a turbine 12 and a compressor coupled thereto 13 in the charge air supply 21 is arranged. Through the compressor 13 The sucked raw air is in the charge air supply line 21 directed. The amount of sucked raw air is also in the second example shown by means of an air flow meter 15 (HFM, hot-film air mass meter).

Notwithstanding the first example, the second embodiment of an internal combustion engine according to the invention 1 two devices for tempering, ie for adjusting the temperature of the sucked raw air. In addition to already in 1 shown first device 3 in the form of a heat exchanger (eg, intercooler) is still a device according to the second example 4 for heating the raw air available. In the example shown, such a heating device 4 for example in the form of baffles at the exhaust gas outlet 25 (Rohluft uncooled exhaust gas heat exchanger device) may be provided. With the help of such baffles, which may be arranged for example on an exhaust manifold, can be sucked or already sucked air at the exhaust gas outlet 25 are passed, wherein heat energy is transferred from the exhaust gas to the bypassed air. This can be achieved that already in the air filter 14 the temperature T0 of the raw air is raised to a temperature T1. The temperature of the intake air can be within the charge air supply line 21 by one or more corresponding device (s), for example, to transfer heat from the exhaust gas to the intake air, further raised.

Of course, all suitable heating devices may be provided for heating the raw air or the intake air, for example in the form of one or more electric air heater (s), raw air coolant heat exchanger device (s) (for example cooling water of a cooling circuit serves as coolant) and / or unfiltered uncooled exhaust gas heat exchanger device (s) or any combinations thereof. Although not shown here, one or more adjustable bypasses / bypasses may of course also be provided, with the untreated air at least partially distributed to the one or more device (s). 4 for heating the raw air can be passed. This percentage can range from 0% to 100%, with any intermediate values possible (eg 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%). , 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%).

Another difference compared to the internal combustion engine 1 exists in the internal combustion engine 1 according to the second example in that in this a first valve 5 in the charge air supply line 21 upstream of the first cooling device 3 is arranged. With the help of this first valve 5 and a second flow path 23 forming conduit is an adjustable bypass parallel to the first flow path 22 with the first cooling device contained therein 3 formed, with which an adjustable proportion of the intake air to the device 3 can be bypassed. This percentage can range from 0% to 100%, with any intermediate values possible (eg 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%). , 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%).

In the internal combustion engine 1 according to the in 2 shown example, as well as in the internal combustion engine 1 according to the in 1 shown example, any suitable device or combination of devices for cooling 3 be supplied from supplied and compressed unfiltered air (charge air). As examples may be mentioned here one or more unfiltered air-heat exchanger device (s), raw air-water heat exchanger device (s) and / or raw air-cooled exhaust gas Heat exchange device (s). In several devices for cooling of supplied and compressed unfiltered air (charge air) can of course also be provided in parallel to the devices, adjustable bypasses.

With respect to the further features of the internal combustion engine 1 according to the in 2 shown second embodiment, reference is made to the above statements to the first embodiment.

Due to the features of the second embodiment, by means of the control device 80 in a particularly flexible manner, a desired value for the intake air temperature T3 of the combustion chamber 18 supplied combustion air as a function of the respective operating mode of the internal combustion engine 1 be set and regulated.

In 3 is also purely schematically a third example of the internal combustion engine according to the invention 1 shown. In the following description of the third example will be discussed in particular the features in which the internal combustion engine 1 according to the third example differs from that according to the first and second examples.

In the 3 shown internal combustion engine based - purely by way of example - on the in 2 shown internal combustion engine, and in addition to the features of the internal combustion engine shown there has a second branch line 72 looking for the diesel particulate filter 17 branches off from the Abgasausleitung, one within the second branch line 72 arranged fourth valve 27 and a third cooling device 28 on. The second branch line 72 opens downstream of the compressor 13 in the charge air supply line 21 , Of course, these additional features according to 3 also be used in an internal combustion engine, such as in 1 is shown.

By means of in 3 illustrated embodiment of the internal combustion engine according to the invention, it is possible, depending on the mode and / or within a mode of operation alternatively or in addition to a via the first branch line 71 carried out high-pressure exhaust gas recirculation also a low-pressure exhaust gas recirculation. Low pressure exhaust gas is due to the path it takes from the combustion chamber 18 over the exhaust pipe 25 has covered up to the exhaust gas outlet, usually already cooler than that through the first branch line 71 directed exhaust. Further cooling is experienced by the exhaust gas through the expansion within the turbine 12 , Due to these two conditions, low-pressure exhaust gas often has a temperature which is lower by about 100 ° C. to 150 ° C. than high-pressure exhaust gas.

The amount and / or temperature of the low-pressure exhaust gas, which is supplied to the charge air, via the fourth valve 27 and / or the third cooling device 28 be set / regulated.

Due to the option of being able to mix (also) low-pressure exhaust gas of the charge air, there is advantageously a very flexible solution for setting / regulating the setpoint temperature of the charge air and thus also the combustion air.

In the following some exemplary modes are set out, in which by means of the internal combustion engine according to the invention 1 possible air temperature management method advantageously the combustion or the operation of the self-igniting internal combustion engine can be optimized:

normal operation

When the engine is started after a longer standstill (i.e., the engine block is at a temperature substantially at ambient temperature), within a first period of time, the temperature of the combustion air is set above the temperature intended for normal operation in the range of about 30 ° C to 70 ° C. This also increases the exhaust gas temperature, which in turn allows a more rapid "light-off" of the diesel oxidation catalyst can be achieved than would be possible at a "normal temperature" of the combustion air in the range of about 30 ° C to 70 ° C.

If the "light-off" of the diesel oxidation catalyst is reached or if a corresponding temperature of the diesel oxidation catalyst is measured, the temperature of the combustion air can be lowered to a range of about 30 ° C. to 70 ° C. according to the invention.

The present invention thus advantageously makes it possible to set different temperatures of the combustion air to a desired temperature or a desired temperature range with a narrow temperature band not only for different operating modes but also within one operating mode of the internal combustion engine.

Full load; Summer operation:

The raw air is through the air filter 14 (Airbox) sucked into the compressor and in a charge air cooler 3 cooled. At the same time, a large portion or all of the recirculated exhaust gas by means of the cooling device 8th cooled. this leads to total to a low, by means of the control device 80 controllable intake air temperature T3 of the combustion air.

Partial load; Winter operation:

Raw air (intake air) is on its way into the combustion air supply line 24 heated. Depending on the desired intake air temperature T3, this may be advantageous when the cooling device 3 with the help of the first valve 5 and the second flow path 23 at least partially bypassed.

Depending on the desired intake air temperature T3 can by means of the control device 80 also the proportion of recirculated exhaust gas passing through the second cooling device 8th is passed by the third valve 11 be set and regulated.

In cold ambient conditions is a "light-off" of the diesel oxidation catalyst 16 (DOC) often delayed or it is difficult to maintain the light-off. Even in coasting or low-load driving, there is a risk of cooling the DOC in the prior art 16 below the light-off temperature, and thus the risk of insufficient or even complete failure of the catalytic activity of the DOC 16 , This can lead to high hydrocarbon emissions (HC emissions), which in turn can be visible as "white smoke" at the exhaust end pipe and can be perceived olfactorily. By an inventive recirculation uncooled exhaust gas and / or heating the raw air, the heating of the DOC 16 accelerates or slows down its cooling. This is within an operating period of the internal combustion engine according to the invention 1 a significantly increased proportion of time with a catalytically active DOC 16 reachable.

Cold intake air also adversely affects combustion; it is at least partly responsible for high raw emissions and a non-optimal, rough engine noise (Noise Vibration Harshness, NVH). In the prior art, in order to improve the NVH, the injected pilot amount is increased, but this is associated with an increase in fuel consumption.

According to the invention, the combustion of fuel can be stabilized even in cold ambient conditions by raising the intake air temperature T3 of the combustion air and in comparison to the prior art reduced HC raw emissions can be achieved. Reduced raw HC emissions simultaneously reduce the amount of hydrocarbons produced by a not yet catalytically active DOC 16 can pass through (less white smoke, lower HC smell). Furthermore, a pilot quantity reduction is still possible with good combustion noise; This also achieves a reduced fuel consumption.

At exposed points, for example the point of introduction of recirculated exhaust gas or in the intercooler, according to the prior art, there is an increased risk of condensate formation due to cooling of moist air and / or recirculated exhaust gas. By the present invention, this risk can be at least significantly reduced by raising the intake or combustion air temperature and a temperature control over the entire air gap.

In the "off-cycle" driving operation can by the internal combustion engine according to the invention 1 and the inventive method optimal utilization of all advantages by mixing operation of Ansaugluftvorwärmung and control of the flow of raw air and the recirculated exhaust gas through the cooling devices 3 . 8th be effected. This is especially true at cold ambient temperatures (for example, when using a "Portable Emission Measurement System", PEMS).

Wants a driver full load operation of the internal combustion engine 1 For example, by closing one, several, or all of the bypasses present, a low intake air temperature T3 of the combustion air can be provided almost immediately.

Exhaust Treatment:

Due to the fuel properties and the combustion process, particles are produced during the operation of self-igniting internal combustion engines (diesel engines). These particles are used in modern self-igniting internal combustion engines with the aid of a diesel particulate filter 17 at least partially filtered out of the exhaust.

The particles can be continuously degraded by the so-called CRT effect (Continuously Regenerating Technology). This is done by the DOC 16 converted in the exhaust gases nitrogen monoxide (NO) in nitrogen dioxide (NO ₂ ). This nitrogen dioxide allows continuous combustion of the particles in the filter. However, temperatures T5 between the oxidation catalyst must be 16 and diesel particulate filters 17 be achieved in the range of about 200 to 450 ° C or be given.

Below this temperature range, the particles collect in the diesel particulate filter 17 as soon as they have a certain concentration in the diesel particulate filter 17 have been removed from this to avoid clogging (clogging) of this filter. For this purpose is in a preheat mode (heat-up mode) the temperature of the exhaust gas between the oxidation catalyst 16 and diesel particulate filters 17 increased to a target temperature T5, for example, to a temperature of 500 ° C to 600 ° C. Especially at low loads and frequent overrun operation, however, it is difficult in the prior art to reach this target temperature T5.

In such a situation, therefore, according to the prior art in the exhaust gas discharge 25 Fuel injected (post-injection) in the oxidation catalyst 16 is oxidized and thus the temperature T5 of the exhaust gas in the area after the oxidation catalyst 16 elevated. As a result, an increase in the exhaust gas temperature can be achieved to the target temperature T5, but at the cost of increased fuel consumption.

In contrast, according to the invention for the regeneration of the diesel particulate filter 17 For example, the intake air temperature T3 of the combustion air to be heated to a temperature in the range of 90 ° C to 150 ° C. For this purpose, for example, both the first and the second cooling device 3 . 8th completely bypassed, and by a heating device 4 the temperature T2 of the intake air can be set to any suitable value, for example in the range between 80 ° C and 120 ° C. With the help of not or only partially cooled, recirculated exhaust gas can then be the desired inlet air temperature T3 in the range of 90 ° C to 150 ° C, for example in the range of about 100 ° C to 120 ° C, adjusted.

Such an inventive controlled heating of the intake air temperature T3 to a temperature in the range of about 90 ° C to 150 ° C has a direct, temperature-increasing influence on the generated exhaust gas. Thus, the target temperature T5 can be achieved by the present invention with lower post-injection quantities or even without any post-injection quantities with at the same time lower risk of HC slippage. This also causes an increased oxygen concentration in front of the diesel particulate filter 17 achieved, whereby a more efficient regeneration can be achieved.

Further, by the present invention by means of a rapid reduction of the intake air temperature T3 also a "drop-to-idle" situation can be defused. A "drop-to-idle" situation exists when, after triggering a regeneration phase of the diesel particulate filter 17 the speed of the internal combustion engine 1 quickly drops to an idle level. This has the consequence that in the exhaust gas, the content of oxygen increases, which is the Rußabbrand and thus the formation of very high temperatures in the diesel particulate filter 17 promotes. These high temperatures and in particular an inhomogeneous temperature profile within the diesel particulate filter 17 can destroy the material of the diesel particulate filter 17 have as a consequence.

A rapid down-regulation of the intake air temperature T3 according to the invention leads, in the case of a "drop-to-idle" situation, to a corresponding lowering of the exhaust gas temperature T4, which in turn cools the diesel particulate filter 17 entails. This may reduce the potentially damaging effects of a "drop-to-idle" diesel particulate filter situation 17 be prevented.

Also, it is possible by the present invention, the time interval between two regeneration intervals for the diesel particulate filter 17 be increased by the appropriate temperatures for the CRT effect T5 of the exhaust gas in the range of about 200 to 450 ° C before the diesel particulate filter are achieved by a suitable driving profile even at medium loads and / or in cold environmental conditions.

Emissions test:

In emission mode, for example, the ambient temperature range according to MVEG (Motor Vehicle Emissions Group) can be assumed as ideal. The temperature T1 of the unfiltered air may be set and controlled in the range of 20 to 30 ° C, and an intake air temperature T3 in the range of 30 ° C to 70 ° C.

In addition to advantages in terms of a reduction of the raw HC / CO emissions in the driving cycle according to MVEG, in particular in the -7 ° -MVEG driving cycle, in particular the "light-off" of the diesel oxidation catalyst 16 (DOC), ie the light-off temperature of the diesel oxidation catalyst 16 is achieved earlier and maintained even under unfavorable circumstances longer than this without the internal combustion engine according to the invention 1 and without the inventive method is possible.

In 3 Three exemplary scenarios and control methods are shown with reference to an intake-air temperature-load diagram. In the case of with reference numerals 31 according to the invention is raised from a comparatively low temperature level of below 20 ° C, the intake air temperature T3 according to the invention to a value in the range of about 115 ° C to 225 ° C to a regeneration phase for the diesel particulate filter 17 to initiate or maintain. For this purpose, by means of the internal combustion engine according to the invention 1 and the method according to the invention, the temperature of the intake and compressed air T2 are raised and / or the temperature of the recirculated exhaust gas are not lowered or only to a lesser extent. If no sufficiently hot exhaust gas is available, the Temperature T2 be raised, for example by means of an electric air heater to the required value.

By raising T3 to the specified level, the post-injection quantities (also referred to as qPost or qPol) can be reduced, thus optimizing fuel consumption.

Starting point of the reference number 32 Scenarios provided is an emission mode in a cold environment (T3 between 0 ° C and 10 ° C). For example, in order to reach the optimum range of about 40 ° C. to 60 ° C. from T3 for the emission mode, the temperature T1, T2 and T3 can be regulated accordingly. The temperature T1 of the supply air can be increased, for example, by means of the already mentioned above provided on an exhaust manifold air baffles. Within the charge air supply line 21 can then be further increased, for example by means of a second heating device, the temperature of the intake air. By possibly complete bypass of the cooling device 3 by means of the first valve 5 and the second flow path 23 The inlet air then passes at the temperature T2 to the outlet for the recirculated exhaust gas.

The temperature of the recirculated exhaust gas can now be regulated, for example, in such a way that the inlet air temperature T3 of the combustion air formed by the mixture of intake air and recirculated exhaust gas of the target value or the target value range corresponds.

As a result, a safe, economical and low-emission operation of a self-igniting internal combustion engine is ensured even in a cold environment, without the need for a correction of injection parameters in response to a suboptimal combustion air temperature (ATSC = Ambient Temperatures Correction). This also improves emission safety in "off-cycle" operation.

The with the reference number 33 provided scenario starts from a comparatively high inlet temperature T3 of the combustion air in the range of about 105 ° C to 115 ° C (as may occur, for example, in a non-urban operation of an internal combustion engine). In order to reduce the resulting relatively high raw NO _x content in the exhaust gas at this temperature T3, which has a correspondingly increased temperature T4 of the exhaust gas produced, according to the invention, the inlet temperature T3 of the combustion air to the region of about 40 ° C to 60 ° C can be reduced. For this purpose, with the aid of the control device provided in the internal combustion engine according to the invention 80 For example, the various devices for cooling 3 . 8th and rules 5 . 9 . 10 . 11 . 23 within the internal combustion engine according to the invention 1 be suitably used and controlled.

Current CO ₂ emission targets and future regulations place high demands on engine temperature management. By the present invention, it is possible to control the intake air temperature T3 of the combustion air independently of the environment at a desired level. This makes it possible to decouple the combustion of fuel from environmental influences and the temperature balance of the internal combustion engine 1 continue to optimize.

By means of the internal combustion engine according to the invention 1 and the process of the invention, reduced hydrocarbon (HC) and / or carbon monoxide (CO) raw emissions can be achieved. Likewise, the period of time until the light-off of the diesel oxidation catalyst 16 reduced. The emission benefits are achieved both in real ("off-cycle") operation (especially in a cold environment, PEMS) and in emission mode (eg in the MVEG tests, such as the -7 ° C MVEG test ) reached.

Further advantages of the internal combustion engine according to the invention 1 As well as the method according to the invention, the fact that the HC slip (white smoke) optimizes the amount of catalytically active coating in the diesel oxidation catalyst 16 reduces the risk of formation of condensate in the intake tract 21 . 22 . 23 . 24 reduces the amount of fuel required for post-injection and / or pilot injection, reduces the regeneration of the diesel particulate filter 17 optimized by a high combustion air inlet temperature, and by using exhaust heat and LLK bypass / bypasses a CO ₂ neutral air preheating can be achieved.

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

• DE 102006057488 A1 [0004]
• DE 3243016 A1 [0006]
• DE 4222041 A1 [0007]
• DE 19926135 A1 [0008]

Claims (10)

Self-igniting internal combustion engine ( 1 ) with an intake tract ( 21 . 22 . 23 . 24 ) which sucks in a raw air having a first temperature and which has a combustion air having a second temperature at least one combustion chamber ( 18 ), wherein for adjusting the temperature of the combustion air to a target value in the intake tract ( 21 . 22 . 23 . 24 ) at least one device for tempering ( 3 ) the unfiltered air is provided, characterized in that the internal combustion engine ( 1 ) a control device ( 80 ), with which the desired value for different operating modes and / or within an operating mode of the internal combustion engine ( 1 ) is set differently. A compression-ignition internal combustion engine according to claim 1, characterized in that the at least one device for tempering ( 3 ) the unfiltered air has a unfiltered air-to-air heat exchanger device, raw air to water heat exchanger device and / or unfiltered air cooled exhaust gas heat exchanger device, whereby the temperature of raw air can be lowered. A compression-ignition internal combustion engine according to claim 1 or 2, characterized in that the at least one device for controlling the temperature of the raw air ( 4 ) comprises an electric air heater, a raw air refrigerant heat exchanger device and / or raw air uncooled exhaust heat exchanger device, whereby the temperature of raw air can be increased. A compression-ignition internal combustion engine according to any one of the preceding claims, characterized in that it comprises at least one adjustable bypass device ( 5 . 23 ) for the at least proportionate bypassing of unfiltered air to the at least one device for tempering ( 3 ) has the raw air. A compression-ignition internal combustion engine according to any one of the preceding claims, characterized in that it further comprises at least one exhaust gas recirculation device ( 7 ) for returning at least part of the engine ( 1 ), wherein the at least one exhaust gas recirculation device ( 7 ) at least one device for cooling ( 8th ) of the exhaust gas and at least one adjustable bypass device ( 10 . 11 ) for at least partially bypassing exhaust gas at the at least one device for cooling ( 8th ) of the exhaust gas. A compression-ignition internal combustion engine according to one of the preceding claims, characterized in that by means of the control device ( 80 ) the setpoint of the combustion air is adjusted to a temperature in the range between 30 ° C and 150 ° C, depending on the operating mode and / or within one operating mode. A compression-ignition internal combustion engine according to claim 6, characterized in that the setpoint value for a regeneration phase of a diesel particulate filter ( 17 ) is set to a temperature in the range of 90 ° C to 150 ° C, and / or for a normal operating mode to a temperature in the range of 30 ° C to 70 ° C. Method for operating a self-igniting internal combustion engine, in which a, a first temperature having a raw air intake via an intake and a second temperature having combustion air is supplied to at least one combustion chamber, wherein for adjusting the temperature of the combustion air to a target value in the intake system at least one device is provided for controlling the raw air temperature, characterized in that by means of a control device, the desired value for different operating modes and / or is set differently within an operating mode of the internal combustion engine. A method according to claim 8, characterized in that by means of the control device, the desired value is adjusted depending on the operating mode and / or within a mode to a temperature in the range between 30 ° C and 150 ° C. A method according to claim 9, characterized in that by means of the control device, the setpoint for a regeneration phase of a diesel particulate filter to a temperature in the range of 90 ° C to 150 ° C, and / or for a normal operating mode to a temperature in the range of 30 ° C to 70 ° C is set.

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