DE10332208A1 - Device for load control and intake air heating of internal combustion engine, comprises separate airflow feeding mechanisms for altering airflow to internal combustion engine via first and second part-pipes - Google Patents

Abstract

The device comprises separate airflow feeding mechanisms (8,9) which are arranged in a first and second part-pipes (5,6). The airflow feeding mechanisms alter the airflow to the internal combustion engine, via the first and second part-pipes, independently of each other, between a minimum and a maximum value. The second part-pipe (6) is guided to the exhaust heat exchanger (7) of the exhaust system (4), and then to the internal combustion engine. The second part-pipe has a smaller cross-section than the first one.

Description

The The invention relates to a device for load control and intake air heating of an internal combustion engine, which is connected to an intake system and to an exhaust system is, according to the closer defined in the preamble of claim 1 Art.

A generic device is from the DE 41 04 011 C1 known. In this case, a partial line branches off from the intake line, which absorbs heat in an exhaust gas heat exchanger from the exhaust gas from the exhaust system and, after the exhaust gas heat exchanger, returns to the intake line. The adjustment between the main intake and the sub-line is performed by means of an adjustable flap, the position of which is controlled depending on the speed of the internal combustion engine and a load default. This makes it possible to increase the intake temperature of the internal combustion engine and to carry out a load control of the internal combustion engine as a function of the intake temperature.

The described power control of the internal combustion engine by the Regulation of the inlet temperature leads due to the density change the intake air to changes in charge, What a dethrottling and thus a reduction in consumption of Internal combustion engine has the consequence. Furthermore, the internal combustion engine at higher Temperatures and a higher Pressure and thus closer at its optimal operating point exaggerated and it finds particular At low part load better combustion takes place.

The However, known device has several disadvantages that a Implementation of this device in practice so far have prevented. A big Problem is that the exhaust pipes through the entire Engine room led Need to become, to heat the intake air in the sub-line. This will make the whole Engine room heated considerably, especially because to achieve the desired Effect very high temperature differences are required. at the device described would be For this reason, such a high insulation costs necessary that This is not the space in the engine compartment of an internal combustion engine could agree. Due to the high mass of the pipelines, high heat capacities are created again to high heat losses and a lethargic Responsiveness lead.

Already in MTZ 27/7, pages 283-290 is the warming described the intake air supplied to an internal combustion engine. There are also the given this process underlying physical relationships.

It Object of the present invention, a device for load control and intake air heating an internal combustion engine, which the above-described Avoid disadvantages and offers a realizable in practice solution.

According to the invention this Problem solved by the features mentioned in claim 1.

According to the invention each of the two sub-lines own air quantity allocation device on, which eliminates the switching between the two lines and advantageously much lower flow losses occur. in this connection can the air quantity distributing means independently into their respective Position to be brought in this way, the internal combustion engine supplied amount of air over each Sub-line independent from the other sub-line to steer and thus a mixture between the air streams in the two sub-lines in any ratio to to reach. This allows the internal combustion engine, especially at low loads as well as during cold start, heated air is supplied via the intake system, which at low part load to a better combustion of the internal combustion engine leads and when cold starting the same for a faster heating of a arranged in the exhaust system Catalyst ensures.

According to the invention second part line, in which the internal combustion engine, the heated intake air supplied is led to the exhaust system and not as in the prior art, the exhaust system to this sub-line, i.e. the intake air is guided past the exhaust gas and not vice versa. On This way will be a warming of the engine compartment through the heated Exhaust pipes avoided, resulting in an unrealistically large insulation This exhaust pipes can be dispensed with. Rather, the exhaust system despite being made possible by them warming the intake air and the resulting benefits are carried out as usual, so that the warm exhaust gases are removed as quickly as possible from the engine compartment can.

A considerable advantage of the device according to the invention is attributable to the fact that the second sub-line, which supplies the heated intake air to the internal combustion engine, has a smaller cross-section than the first sub-line. As a result, advantageously, the first sub-line, which supplies cold fresh air to the internal combustion engine, can be made as large as it is for a good full-load behavior of the internal combustion engine, ie a high torque and a high level of noise associated therewith required. The second sub-line, so the hot system, however, can be so small leads out that only a small surface area and a low mass of the line and a small air mass in the line results, whereby a low heat radiation is achieved in the engine compartment. It should be noted that any resulting pressure losses due to the small cross sections do not affect the full load behavior of the internal combustion engine, since in the full load, the second sub-line is substantially closed and the engine only cold air is supplied via the first sub-line. Furthermore, any pressure losses within the intake system are not important in the partial load range, in particular because the pressure losses decrease with increasing air temperature at a constant volume flow. The low mass of the lines leads due to the low heating of the same turn to low heat losses, which allows a faster response of the device according to the invention and thus also the internal combustion engine.

The inventive device allows So, taking advantage of a temperature-dependent load control, such as dethrottling the internal combustion engine, better mixture preparation, Improvement of ignitability and larger cylinder internal flow movement, without that the disadvantages of known solutions must be accepted.

In In practice, a cross-sectional ratio of the second sub-line has to the first part of 0.01 to 0.5 as very beneficial exposed.

In a further advantageous embodiment of the invention can be provided be that the first sub-line has inlet channels leading to each individual cylinder, wherein each inlet channel a closure flap is arranged. alternative or in addition is it possible, the second subline has inlet channels leading to each individual cylinder, wherein in each inlet channel a closure flap is arranged.

By both versions is achieved that the first part of line separated from the second part of line can be what a crosstalk between the cylinders at full load and prevents heat dissipation reduced from the second part of the line in the first part of line.

Further yield advantageous embodiments and refinements of the invention from the remaining subclaims as well as from the following principle illustrated by the drawing Embodiments.

there demonstrate:

1 a first embodiment of the device according to the invention for load control and intake air heating of an internal combustion engine;

2 a second embodiment of the device according to the invention for load control and intake air heating of an internal combustion engine;

3 a third embodiment of the device according to the invention for load control and intake air heating of an internal combustion engine;

4 A fourth embodiment of the device according to the invention for load control and intake air heating of an internal combustion engine;

5 a fifth embodiment of the device according to the invention for load control and intake air heating of an internal combustion engine;

6 a sixth embodiment of the device according to the invention for load control and intake air heating of an internal combustion engine;

7 a seventh embodiment of the device according to the invention for load control and intake air heating of an internal combustion engine; and

8th An eighth embodiment of the device according to the invention for load control and intake air heating of an internal combustion engine.

1 shows an internal combustion engine 1 of which in the present case two of any number of cylinders 2 are shown. The internal combustion engine 1 This is done in series construction, but it could also be an internal combustion engine 1 act in V or any other construction.

To the internal combustion engine 1 carries a connected with the same intake system 3 that of the internal combustion engine 1 Fresh air feeds. That when burning in the cylinders 2 Exhaust gas is produced by an internal combustion engine 1 connected exhaust system 4 from an engine compartment, not shown, in which the internal combustion engine 1 is located, discharged. The intake system 3 has a first subline 5 on, which can also be referred to as a "cold" line, since they are the internal combustion engine 1 supplies unheated or cold fresh air. Furthermore, the intake system 3 a second sub-line 6 which, as described below ben, the internal combustion engine 1 supplying heated fresh air. To the first sub-line 5 and to the second sub-line 6 close each supply lines 5a and 6a on, connecting to the cylinders 2 produce. The supply lines 5a the first sub-line 5 due to their function in the following as swing tubes 5a designated. This takes place before entering the cylinder 2 a mixing of the cold air from the first part line 5 with the heated air from the second partial line 6 , so that the intake air at a certain temperature in the cylinder 2 entry.

For the purpose of heating the air contained in the first part or this flowing through an exhaust gas heat exchanger 7 provided, on the one hand by the exhaust gas of the exhaust system 4 and on the other hand from the second sub-line 6 flowing through fresh air flow rate. The in the second sub-line 6 located fresh air quantity thus decreases in the exhaust gas heat exchanger 7 thermal energy from the exhaust gas and heats up in this way. This allows the cylinders 2 via the second sub-line 6 and the second part of the line 6 subsequent supply lines 6a heated air to be supplied, which is particularly the cold start and the partial load operation of the internal combustion engine 1 to a faster heating of an in 1 not shown catalyst or to a better combustion in the cylinders 2 and a dethrottling leads.

For controlling the internal combustion engine 1 amount of air supplied, and in particular the temperature of this amount of air, resulting from the ratio of the mass flow in the first part line 5 to the mass flow in the second part line 6 results is in the first sub-line 5 a first air quantity distribution device 8th and in the second sub-line 6 a second air quantity allocation device 9 arranged. Both air quantity distribution devices 8th and 9 are formed in the present case as throttle valves and are adjustable between each open and closed positions, not shown, whereby they are able to that of the internal combustion engine 1 over the first part line 5 supplied amount of air regardless of the internal combustion engine 1 via the second sub-line 6 to change the supplied amount of air between a minimum value and a maximum value. The minimum value of the supplied air quantity is in each case zero, that is to say no supplied air quantity, and results from the closed position of the air quantity distribution devices 8th and 9 , In contrast, the maximum value results when the Luftmengenzuteileinrichtungen 8th and 9 in their open position, whereby this mainly from the cross section of the two sub-lines 5 and 6 and the respective flow rate depends.

At full load of the internal combustion engine 1 However, only the Luftmengenzuteileinrichtung 8th opened to the internal combustion engine 1 supply as fresh as possible fresh air, ie the Luftmengenzuteileinrichtung 9 in the second sub-line 6 is closed. At partial load of the internal combustion engine 1 a mixed control between the temperature control and the conventional throttle control is possible, wherein the Luftmengenzuteileinrichtungen 8th and 9 act as "ordinary" throttle valves.

Instead of throttle valves could be the Luftmengenzuteileinrichtungen 8th and 9 and here in particular the Luftmengenzuteileinrichtung 9 be designed differently, for example as a control valve, for example in the form of a plate or rotary valve.

To the internal combustion engine 1 to be able to provide the largest possible amount of air at full load, have the first sub-line 5 and the swing tubes 5a larger cross sections than the second part line 6 and the supply lines 6a , The diameter D _{5 of} the first part line 5 can relative to the diameter D _{6 of} the second sub-line 6 be selected so that the aspect ratio of the second sub-line 6 to the first sub-line 5 0.01 to 0.5. Due to the smaller cross-section of the second sub-line 6 radiates the heated air amount less heat in an engine compartment, not shown, by the internal combustion engine 1 located. As a result, a lower or possibly no insulation of the second sub-line 6 required. Also, the ratio of the diameter D _{5a of} the swing tubes 5a to the diameter D _{6a of} the leads 6a may be similarly selected. In order to achieve an effect which is similar to that of a Schwingsaugrohrs, also the lengths L _{5a of} the oscillating tubes 5a greater than the lengths L _{6a of} the leads 6a As is known, at high speeds and a higher power requirement associated with a larger intake pipe length required or useful. Nevertheless, a shift intake manifold may additionally be provided.

In contrast to the intake system 3 can the exhaust system 4 compared to ordinary internal combustion engines 1 remain unchanged, since the second sub-line 6 to the exhaust system 4 or the exhaust gas heat exchanger arranged therein 7 to be led. This allows a quick discharge of the exhaust gases from the engine compartment, so that it is only slightly heated.

In the embodiment of the device for load control and intake air heating of the internal combustion engine 1 according to 2 are different from the embodiment according to 1 in the supply lines 6a the second sub-line 6 respective closing flaps 10 arranged, in the present case, over a common wave 11 by means of a drive device, not shown, between a Offenstel ment and a closed position are adjustable. By closing the shutters 10 can in full load operation of the internal combustion engine 1 a crosstalk between the two sub-lines 5 and 6 be prevented. Furthermore, it is possible the shutter 10 as air quantity allocation device 9 for the second sub-line 6 to use and thus on the designed as a throttle Luftmengenzuteileinrichtung 9 to renounce.

In the embodiment according to 3 are located inside the swing tubes 5a the first sub-line 5 similar to the flaps 10 according to 2 , executed flaps 12 , Also the flaps 12 are about a common wave 13 from a drive device not shown together adjustable between an open and a closed position. By means of the flaps 12 is it possible to spread heat to the cold sub-pipe 5 to avoid when the cylinders 2 only heated intake air via the second part of line 6 is supplied. Furthermore, also the flaps 12 as air quantity allocation device 8th be used, whereby the running as a throttle Luftmengenzuteileinrichtung 8th could be waived. However, it should be noted that butterfly valves are used as air quantity distributors 8th and 9 especially with regard to metering and dynamic behavior are very well suited.

Instead of the waves 11 and 13 For example, also rods or the like for the flaps 10 and 12 be used or it would be individual drives for each of the flaps 10 and 12 conceivable.

As in 4 shown, both the flaps 10 in the second sub-line 6 as well as the flaps 12 in the first sub-line 5 be provided, which optionally on both Luftmengenzuteileinrichtungen 8th and 9 could be waived. In the embodiment according to 4 is further a catalyst or precatalyst 14 provided in the exhaust system 4 in front of the exhaust gas heat exchanger 7 is arranged. This arrangement contributes to a faster response of the precatalyst 14 during cold start of the internal combustion engine 1 in, since the exhaust gas, the heat only after the pre-catalyst 14 is withdrawn. As described by the described heating of the intake air in the second part of line 6 the exhaust gases have a higher temperature, the catalyst 14 reach its optimum operating temperature faster, which leads to a reduction in exhaust emissions.

In the embodiment of the device for load control and intake air heating of the internal combustion engine 1 according to 5 is in turn the precatalyst or catalyst 14 provided, in this case, however, a common housing 15 with the exhaust gas heat exchanger 7 having. In this way, both a cost and a space reduction can be achieved who the. The remain with reference to 4 described advantages of the arrangement of the exhaust gas heat exchanger 7 after the catalyst 14 receive.

The embodiment according to 6 shows the exhaust gas heat exchanger 7 , which in this case is in an internal combustion engine 1 immediately adjoining exhaust manifold 4a , the part of the exhaust system 4 is, is arranged. As a result, the exhaust heat can be maximally exploited. The dashed line also indicates that the Luftmengenzuteileinrichtung 9 the second sub-line 6 in the flow direction of the intake air also after the exhaust gas heat exchanger 7 can be arranged. This results in a larger volume flow, so that with the smaller adjustable Durchströmspalt a greater control accuracy can be achieved. When the air quantity distribution device 9 in front of the exhaust gas heat exchanger 7 is arranged so it is not thermally stressed. Optionally, air quantity distribution devices are also possible at both positions.

In the embodiment according to 7 branches off the exhaust system 4 an exhaust gas recirculation line 16 on an exhaust gas recirculation valve 17 and ends in the second sub-line 6 the intake system 3 one. The with the exhaust gas recirculation line 16 through feasible exhaust gas recirculation is known per se, but in the present case, by the very low additional cost to a cost reduction and to a larger heat input into the hot system, ie in the second part of line 6 , to lead. The over the exhaust gas recirculation line 16 recirculated exhaust gas is through the exhaust system 4 integrated exhaust gas recirculation valve 17 , which may be of known type, regulated. By such exhaust gas recirculation is an even higher temperature performance or even greater heating in the second part of the line 6 contained intake air possible. In addition, to the auto-ignition within the cylinder 2 the internal combustion engine 1 and to achieve further de-throttling, the exhaust gas recirculation rate increased and run with excess air.

For detecting the mass flows and temperatures are in the embodiment of the device for load control of the internal combustion engine 1 according to 8th in the two sub-lines 5 and 6 each air mass meter 18 and 19 and not shown temperature sensor integrated. These can be controlled by a control unit, also not shown, which also for controlling the Luftmengenzuteileinrichtungen 8th and 9 serve can.

In an embodiment, not shown, the first part line 5 also have several floods.

Claims (11)

Device for load control and intake air heating of an internal combustion engine, which is connected to an intake system and with an exhaust system, wherein the intake system comprises a first part line which supplies fresh air to the internal combustion engine, and a second part line, which is guided by an exhaust gas heat exchanger through which the exhaust gas of the exhaust system in order to heat the fresh air contained in the second part line, characterized in that in the first part line ( 5 ) and in the second sub-line ( 6 ) each separate Luftmengenzuteileinrichtungen ( 8th . 9 ) are arranged, which are capable of that of the internal combustion engine ( 1 ) via the first sub-line ( 5 ) and the second sub-line ( 6 ) to change the amount of air supplied independently of one another between a minimum value and a maximum value, the second part line ( 6 ) to the exhaust gas heat exchanger ( 7 ) of the exhaust system ( 4 ) and from there to the internal combustion engine ( 1 ), and wherein the second sub-line ( 6 ) has a smaller cross section than the first part line ( 5 ). Apparatus according to claim 1, characterized in that the cross-sectional ratio of the second sub-line ( 6 ) to the first sub-line ( 5 ) Is 0.01-0.5. Apparatus according to claim 1 or 2, for load control of an internal combustion engine with a plurality of cylinders, characterized in that the first sub-line ( 5 ) to each individual cylinder ( 2 ) leading vibrating tubes ( 5a ), wherein in each vibration tube ( 5a ) a closure flap ( 12 ) is arranged. Apparatus according to claim 1, 2 or 3, for load control of an internal combustion engine having a plurality of cylinders, characterized in that the second sub-line ( 6 ) to each individual cylinder ( 2 ) leading leads ( 6a ), wherein in each supply line ( 6a ) a closure flap ( 10 ) is arranged. Apparatus according to claim 3, characterized in that in each vibration tube ( 5a ) arranged closure flap ( 12 ) as air quantity allocation device ( 8th ) for the first sub-line ( 5 ) serves. Apparatus according to claim 4, characterized in that in each supply line ( 6a ) arranged closure flap ( 10 ) as air quantity allocation device ( 9 ) for the second sub-line ( 6 ) serves. Device according to one of claims 1 to 4, characterized in that the two Luftmengenzuteileinrichtungen ( 8th . 9 ) are formed as throttle valves, which in the first part line ( 5 ) and in the second sub-line ( 6 ) are arranged and each adjustable between an open position and a closed position. Device according to one of claims 1 to 7, characterized in that the exhaust gas heat exchanger ( 7 ) at one of the internal combustion engine ( 1 ) immediately adjacent exhaust manifold ( 4a ) is arranged. Device according to one of claims 1 to 8, characterized in that the exhaust gas heat exchanger ( 7 ) one in the exhaust system ( 4 ) arranged catalyst ( 14 ) is connected downstream. Apparatus according to claim 9, characterized in that the exhaust gas heat exchanger ( 7 ) a common housing ( 15 ) with the precatalyst ( 14 ) having. Device according to one of claims 1 to 10, characterized in that of the exhaust system ( 4 ) an exhaust gas recirculation line ( 16 ) to the intake system ( 3 ) is guided.