DE102006052216B4 - Sensor module for determining flow variables of a gas flow of an internal combustion engine - Google Patents

Abstract

sensor module for the determination of flow quantities of a Gas stream (3, 15) of an internal combustion engine with a run time from acoustic signals (7, 8) evaluating acoustic flow sensor (1) having a measuring section (6) which can be arranged in a gas line (2, 10) comprises, at the ends of each transducer (4, 5) arranged are characterized in that the sensor module in a further Gas line (12) one for determining flow rates in the further gas line (12) equipped flow sensor (11), which together with the acoustic flow sensor (1) forms a structural unit (13, 18, 20) which is in an approximation area (14, 19) of the two gas lines (2, 10, 12) can be arranged.

Description

The The invention relates to a sensor module for determining flow quantities of a Gas flow of an internal combustion engine with a running time of sound signals evaluating acoustic flow sensor, which comprises a measuring section which can be arranged in a gas line whose ends are each arranged sound transducer.

Such a sensor module is from the EP 0 477 419 A1 known. The known sensor module is provided for installation in the intake manifold of an internal combustion engine and has two ultrasonic transducers, which can operate alternately as transmitting transducers or receiving transducers. The ultrasonic transducers are arranged at the ends of a measuring path inclined against the flow direction. The sound transducers are attached to a bending-resistant and flow-permeable common support structure, so that the two ultrasonic transducers form a structural unit that can be inserted into the wall of the intake manifold.

In order to reduce pollutant emissions, exhaust gas recirculation is provided in modern internal combustion engines. In this case, exhaust gas of the internal combustion engine supplied air is added. The admixture of exhaust gas can lower the peak temperature of the combustion process. This reduces in particular the emission of NO _x . It can also reduce fuel consumption.

The Control of the exhaust gas recirculation valve and the throttle regulating the airflow is usually done with the help of mathematical models, where the air mass flow considered which, with the help of an air mass sensor in the suction line the internal combustion engine is measured. The mass flow of through the exhaust gas recirculation flowing exhaust gas is not recorded.

Furthermore, from the DE 10 2004 038 988 B3 a flow sensor is known, which has a substrate extending in adjacent flow channels, which has in each of the two flow channels in each case a heating arm and a temperature measuring arm. On the heating arm in each case a heating element is arranged, while the temperature measuring arm is provided with a temperature sensor. With the known flow sensor, the gas mass flows can be detected in adjacent flow channels.

outgoing From this prior art, the invention is based on the object a compact sensor module for the determination of flow rates of different gas flows of a To create an internal combustion engine.

These The object is achieved by a sensor module having the features of the independent claim. In it dependent claims Advantageous embodiments and developments are given.

The Sensor module determines the flow rates of gas streams in different gas lines, placing the sensor module next to the acoustic Sensor in one gas line in another gas line via a another flow sensor features, the together with the acoustic flow sensor, a structural unit that forms in the proximity area the two gas lines can be arranged. Under proximity area is to understand a section of the gas lines in which a bottleneck is located between the two gas lines or one muzzle one gas line is present in the other gas line. The Sensor module thus makes use of the fact that gas lines of internal combustion engines frequently run at a small distance from each other, so with the help of a single sensor module flow rates of Gas flows can be determined in the different gas lines. Advantageous is in particular that not separate bays for the individual flow sensors must be provided so that space can be saved.

at a preferred embodiment forms the sensor module together with sections of the adjacent one Gas lines a unit. This will cause the mounting of the sensor module much easier in the internal combustion engine. Because the connection from sections of the gas lines to further gas lines in the internal combustion engine is usually easier than mounting the bare flow sensors into the gas pipes in the engine compartment.

at a further preferred embodiment is the sensor module in the vicinity an estuary the two gas lines arranged. Near a confluence point, the gas pipes run usually with a small distance to each other, so that a particularly compact design results.

Besides it is also possible the sensor module for to provide an area in which the gas lines are in a minimum Walk past each other.

Preferably the acoustic sensor is arranged in an exhaust pipe. Because with acoustic sensors can also gas flows, which have high temperatures are detected.

The further sensor may, for example, be arranged in an intake line of the internal combustion engine. As the temperature of the through the Suction line inflowing air is substantially equal to the ambient temperature, and thermal flow sensors can be used for the intake manifold.

Preferably is called a flow sensor in the other gas line also an acoustic flow sensor used.

In addition, components can a drive circuit for both acoustic flow sensors be used.

Further Advantages and properties will be apparent from the following description in the embodiments the invention with reference to the attached Detailed explanation of the drawing become. Show it:

1 the construction of an acoustic flow sensor;

2 a sensor module disposed in the vicinity of a mouth of an exhaust gas recirculation line in an intake pipe;

3 a further sensor module, which is arranged in the mouth region of an exhaust gas recirculation line in a suction line;

4 a sensor module which is arranged in the region of a constriction between an intake pipe and an exhaust gas recirculation line.

1 shows the construction of an acoustic flow sensor 1 , with which flows of a gas line 2 flowing gas flow 3 to record. In particular, can be with the help of the acoustic flow sensor 1 the flow rate of the gas flow 3 measured. For measuring the gas flow 3 indicates the acoustic flow sensor 1 ultrasound transducer 4 and 5 on, the one opposite the gas flow 3 inclined measuring section 6 define. Along the measuring route 6 be from the ultrasonic transducers 4 and 5 ultrasonic signals 7 and 8th sent. From the transit times of the oppositely directed ultrasonic signals 7 and 8th can then be in one of the ultrasonic transducers 4 and 5 downstream evaluation unit 9 the flow rate of the gas flow 3 be determined.

According to 2 is the acoustic flow sensor 1 in an exhaust pipe 10 arranged. The acoustic flow sensor 1 who is in the exhaust pipe 10 is arranged, further forms together with an acoustic flow sensor 11 who is in an intake pipe 12 located, a structural unit 13 as a whole, near a mouth 14 the exhaust pipe 10 in the intake pipe 12 can be introduced. For this purpose, in the exhaust pipe 10 and in the intake pipe 12 suitable openings may be provided through which the acoustic flow sensors 1 and 11 in the exhaust pipe 10 and the intake pipe 12 let it slide in. In this case, the ultrasonic transducers 4 and 5 the acoustic flow sensors 1 and 11 held by a common bracket.

In addition, it can be provided that the acoustic flow sensors 1 and 11 along with sections of the exhaust pipe 10 and the intake manifold 12 a structural unit 13 form. In this case, the assembly in the engine compartment is greatly facilitated because only the sections of the exhaust pipe 10 and the intake manifold 12 each in the exhaust pipe 10 and the intake pipe 12 must be introduced. The installation of the acoustic flow sensors in the sections of the exhaust pipes 10 and the intake manifold 12 can be done outside the engine compartment. There are the flow sensors 4 and 5 much easier to access.

The distance of the acoustic flow sensors 1 and 11 to the mouth 14 is preferably chosen so that no crosstalk of the ultrasonic signals 7 and 8th from the flow sensor 1 to the flow sensor 11 and vice versa is possible.

With the help of the unit 13 allows the flow rate of an exhaust gas flow 15 and an airflow 16 determine. Behind the mouth 14 form the exhaust gas flow 15 and the airflow 16 a mixed gas flow 17 one in 2 Internal combustion engine, not shown, is supplied. The exhaust gas flow 15 it serves the exhaust gas recirculation, whereby the peak temperatures are reduced during combustion and the emission of pollutants of the internal combustion engine is reduced.

By the unit 13 Only a single slot is used. The fact is exploited that the exhaust pipe 10 and the intake pipe 12 in the area of the estuary 14 at a small distance from each other, so that the structural unit 13 only relatively little space needed.

In 3 is the case shown that the exhaust pipe 10 and the intake pipe 12 in front of the mouth 14 at an angle. In this case, the acoustic flow sensors 1 and 11 a structural unit 18 form, in which the acoustic flow sensor 1 and the acoustic flow sensor 11 starting from the mouth 14 each in the of the exhaust gas flow 15 flowed through the exhaust pipe 10 and in that of the air flow 16 flowed through intake pipe 12 extend.

Besides, it is possible that the unit 18 the sections of the exhaust pipe 10 and the intake manifold 12 include the mouth 14 form. In this case, the unit represents 18 a mouth piece that with the acoustic flow sensor 1 and the acoustic flow sensor 11 for measuring the exhaust gas flow 15 and airflow 16 just before the mouth 14 Is provided.

At the in 3 illustrated embodiment is to ensure that the ultrasonic signals 7 and 8th do not interfere. Because of this, are in 3 the ultrasonic transducers 4 and 5 arranged in series one behind the other, so that the individual ultrasonic transducers shade each other. Optionally, the separation of the ultrasonic signals 7 and 8th the individual flow sensors 1 and 11 also be accomplished by the fact that the sound transducer 1 and 11 be operated alternately. In addition, between the ultrasonic transducer 5 of the flow sensor 1 and the ultrasonic transducer 4 of the flow sensor 11 one approximately at right angles to the longitudinal axis of the flow transducer 1 and 11 aligned aperture, through which the flow sensors 1 and 11 against the ultrasonic signals 7 and 8th the other flow sensor 1 or 11 to be shaded.

In 4 is still the case shown that between the exhaust pipe 10 and the intake pipe 12 a bottleneck 19 is present, in the area of a structural unit 20 can be arranged, which is the acoustic flow sensor 1 and acoustic flow sensor 11 includes, respectively, the exhaust flow 15 in the exhaust pipe 10 and the airflow 16 in the intake pipe 12 to capture.

It should be noted that instead of the acoustic flow sensor 1 in the area of the intake pipe 12 Also, a thermal flow sensor may be provided. In particular, hot-wire air mass flow meters or hot-film air mass flow meters are contemplated, in which a heating element is part of an electrical bridge circuit and in which the current flowing through the heating element at a constant excess temperature to the temperature of the air flow 16 is held.

The use of a thermal flow sensor for the flow sensor 1 offers the advantage that no special measures for the acoustic decoupling of the flow sensors 1 and 11 must be taken, as the two flow sensors 1 and 11 work according to different measuring principles.

It should also be noted that due to the rapid pollution by exhaust gas and because of the high temperatures of the exhaust gas, the acoustic flow sensor 1 who is in the exhaust pipe 10 usually can not be replaced by a thermal flow sensor.

In conclusion, be noted that features and properties related with a particular embodiment have been described, also with another embodiment can be combined except when for reasons the compatibility is excluded.

Finally will it should be noted that in the claims and in the description the singular includes the plural except when out of context something else results. Especially if the indefinite article is used, both the singular and the plural is meant.

1

acoustic flow sensor

2

gas pipe

3

gas flow

4

ultrasound transducer

5

ultrasound transducer

6

measuring distance

7

ultrasonic signal

8th

ultrasonic signal

9

evaluation

10

exhaust pipe

11

acoustic flow sensor

12

intake

13

unit

14

muzzle

15

exhaust gas flow

16

airflow

17

Gas mixture flow

18

unit

19

bottleneck

20

unit

Claims (11)

Sensor module for determining flow quantities of a gas stream ( 3 . 15 ) of an internal combustion engine with a running time of sound signals ( 7 . 8th ) evaluating acoustic flow sensor ( 1 ), one in a gas line ( 2 . 10 ) arrangeable measuring section ( 6 ), at whose ends each sound transducer ( 4 . 5 ) are arranged, characterized in that the sensor module in a further gas line ( 12 ) one for determining flow quantities in the further gas line ( 12 ) furnished flow sensor ( 11 ), which together with the acoustic flow sensor ( 1 ) an assembly ( 13 . 18 . 20 ) which forms in egg proximity ( 14 . 19 ) of the two gas lines ( 2 . 10 . 12 ) is arrangeable. Sensor module according to claim 1, characterized in that the flow sensors ( 1 . 11 ) together with sections of the gas lines ( 2 . 10 . 12 ) form a structural unit. Sensor module according to claim 1 or 2, characterized in that the flow sensors ( 1 . 11 ) in front of a mouth ( 14 ) of a gas line ( 10 ) into the other gas line ( 12 ) are arrangable. Sensor module according to claim 3, characterized in that the flow sensors ( 1 . 11 ) in a region of adjacent gas lines ( 10 . 12 ) are arrangable. Sensor module according to claim 3, characterized in that the flow sensors ( 1 . 11 ) are arranged in an area in which the gas lines ( 2 . 10 . 12 ) at an angle to each other. Sensor module according to claim 1 or 2, characterized in that the flow sensors ( 1 . 11 ) in the region of one between the gas lines ( 2 . 10 . 12 ) bottleneck ( 19 ) are arrangable. Sensor module according to one of claims 1 to 6, characterized in that one of the gas lines an exhaust pipe ( 10 ) and the exhaust pipe associated flow sensor of the acoustic flow sensor ( 1 ). Sensor module according to one of claims 1 to 7, characterized in that the further flow sensor ( 11 ) in a suction line ( 12 ) of the internal combustion engine is located. Sensor module according to claim 8, characterized in that the further sensor ( 11 ) is a thermal sensor. Sensor module according to claim 9, characterized in that the further sensor is an acoustic sensor ( 11 ). Sensor module according to one of claims 1 to 10, characterized in that the flow sensors ( 1 . 11 ) a common evaluation unit ( 9 ) exhibit.