Cooling device for a flow sensor in an exhaust gas recirculation line

A cooling device includes a case delimiting an air circulation enclosure. The case comprises an air intake opening intended to be connected to an air inlet, and an air outlet opening intended to be connected to a heat engine. The cooling device includes an exhaust gas driving device housed at least partially in the air circulation enclosure. The exhaust gas driving device includes at least one exhaust gas flow sensor, each flow sensor being housed entirely in the air circulation enclosure of the case.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. non-provisional application claiming the benefit of French Application No. 19 13786, filed on Dec. 5, 2019, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to a cooling device for a flow sensor of a recirculated exhaust gas from a heat engine.

BACKGROUND

Such a cooling device is generally used in conjunction with an exhaust gas recirculation line. An exhaust gas recirculation line is intended to redirect part of the exhaust gases of a combustion engine toward an intake manifold of this engine, in order to reduce the emissions of nitrogen oxides NOx for diesel engines and the CO2emissions for gasoline engines.

The quantity of exhaust gas redirected into the recirculation line is regulated by a flow regulating valve, and the exhaust gas flow rate in the recirculation line is measured by at least one flow sensor equipping the driving device.

SUMMARY

The disclosure, in particular, aims to improve the behavior of the flow sensor.

The disclosure in particular relates to a cooling device for at least one flow sensor for recirculated exhaust gases from a heat engine, wherein the cooling device includes a case delimiting an air circulation enclosure. The case comprises an air intake opening intended to be connected to an air inlet, and an air outlet opening intended to be connected to the heat engine. The cooling device includes an exhaust gas driving device housed at least partially in the air circulation enclosure, the exhaust gas driving device including at least one exhaust gas flow sensor, with each flow sensor being housed entirely in the air circulation enclosure of the case.

The sensors of the state of the art being intended to measure the exhaust gas flow rates, they are generally subject to high temperatures (which are on the one hand the temperature of the recirculated exhaust gases and on the other hand the ambient temperature in the engine compartment). Now, it has been noted that the behavior of the flow sensors decreases when the temperature becomes too high, in particular above 100° C.

The disclosure aims to cool the flow sensors at a lower cost and effectively.

By housing the flow sensors entirely in the air circulation enclosure of the cooling case, these flow sensors are cooled by the air circulating in this cooling case. Their lifetime is improved as a result.

A cooling device according to the disclosure may further include one or more of the following features, considered alone or according to all technically possible combinations.Each flow sensor is formed by an ultrasonic transmitter or an ultrasonic receiver.The driving device includes a flow regulating valve, the regulating valve being housed inside the enclosure of the case.The driving device includes a flow regulating valve, the regulating valve being housed outside the enclosure of the case, upstream or downstream of this case.The flow regulating valve is arranged upstream of each flow sensor.The flow regulating valve is arranged downstream of each flow sensor.The driving device includes a tubular exhaust gas circulation pipe, which is connected to the case by fitting in a receiving orifice of the tubular pipe.The cooling device includes a downstream pipe connected to the outlet opening, the circulation pipe passing through the enclosure and being extended by an outlet pipe opening into the downstream pipe.The circulation pipe opens into the enclosure.

The disclosure also relates to an air intake line, including an air inlet, wherein the air intake line includes a cooling device as previously defined, the air intake opening of which is connected to the air inlet.

DETAILED DESCRIPTION

FIG. 1shows a cooling device10for a flow sensor of recirculated exhaust gases from a heat engine.

The cooling device10includes a case12, delimiting an air circulation enclosure14.

The case12includes an air intake opening16, which is intended to be connected to an air inlet using upstream pipes17, and an air outlet opening18which is intended to be connected to the heat engine using downstream pipes19, in order to supply the latter with air. It will be noted that in the present description, the terms “upstream” and “downstream” are considered based on the direction of flow of a fluid, here the air circulating in the enclosure14.

The cooling device10also includes a device20for driving exhaust gases, housed at least in part in the enclosure14. This driving device20is intended to equip an exhaust gas recirculation line.

The driving device20includes a tubular pipe22, arranged downstream of recirculation pipes coming from the heat engine. Thus, a portion of the exhaust gases coming from the heat engine is directed toward the driving device20. As previously indicated, in the present description, the terms “upstream” and “downstream” are considered based on the direction of flow of a fluid. Here, the fluid is the exhaust gases circulating in the tubular pipe22.

The tubular pipe22extends at least partially in the enclosure14. Thus, this tubular pipe22is, for example, fitted in a receiving orifice23of this pipe, arranged in the case12.

The driving device20includes at least one exhaust gas flow sensor24. More particularly, the driving device20includes at least two flow sensors24, preferably four flow sensors24, arranged to measure a flow rate of exhaust gas circulating in the tubular pipe22.

The driving device20includes power supply elements. More particularly, each sensor24is powered by a respective power supply element. These power supply elements are, for example, connected to a general power supply input element, which in turn is intended to be connected to an electricity source.

Advantageously, the flow sensors24include at least one ultrasonic transmitter and at least one ultrasonic receiver associated with the ultrasonic transmitter.

More particularly, the flow sensors24include two ultrasonic transmitters and two ultrasonic receivers, each associated with a respective one of the ultrasonic transmitters. The transmitters and the receivers therefore form pairs. The transmitter and the receiver of each pair are aligned facing one another, along an axis specific to this pair.

It will be noted that preferably, each sensor24is formed by a transducer able to serve as transmitter or receiver.

The transmitter and the receiver of each pair are generally arranged facing one another, on either side of the tubular pipe22. Thus, the exhaust gases circulate between this transmitter and this receiver. The transmitter emits ultrasounds, which are received by the receiver. The duration between the transmission and the reception depends on the flow of exhaust gas circulating between the transmitter and the receiver. It is thus possible to determine the flow of exhaust gas as a function of this measured duration, in a manner known in itself.

According to the disclosure, each flow sensor24is housed entirely in the enclosure14of the cooling case12. “Housed entirely” means that all of the components of the sensor24are housed in the enclosure, namely its measuring part and its electronic part. Of course, the sensors24remain carried by the tubular pipe22, in order to measure the flow of gas in this tubular pipe22.

Advantageously, the tubular pipe22includes lateral through openings, through which the sensors24pass. Thus, each sensor24has an end turned toward the flow of exhaust gas circulating in the tubular pipe22, and an end protruding outside the tubular pipe22, in the enclosure14.

It will be noted that the case12is preferably configured to direct the incoming flow of air toward the sensors24. Thus, the sensors24are arranged in the extension of the air intake orifice16, as shown inFIG. 1.

As in particular shown inFIG. 2, according to the first embodiment, the tubular pipe22emerges (at a downstream end) in the enclosure14. Thus, the recirculated exhaust gas is mixed with the air directly in the enclosure14before being sent toward the heat engine.

According to this first embodiment, the tubular pipe22is connected, at an upstream end26, to an exhaust gas intake pipe28. This connection, is for example, done by fitting the upstream end26of the tubular pipe22in the intake pipe28.

It should be noted that the recirculation line conventionally includes a flow regulating valve30in order to regulate the flow circulating in the tubular pipe22. According to this first embodiment, the regulating valve30is arranged in the intake pipe28, upstream of the connection with the tubular pipe22.

The regulating valve30could be arranged in other locations, according to variants that will be described later.

FIG. 3shows a cooling device10according to a second example embodiment. In this figure, the elements that are similar to those of the preceding figures are designated using identical references.

According to this second embodiment, the tubular pipe22is secured to the intake pipe28. For example, the tubular pipe22and the intake pipe28together form a single pipe in one piece. In a variant, the tubular pipe22is welded to the intake pipe28.

It will be noted that, like in the first embodiment, the tubular pipe22opens into the enclosure14.

FIG. 4shows a cooling device10according to a third example embodiment. In this figure, the elements that are similar to those of the preceding figures are designated using identical references.

According to this third embodiment, the tubular pipe22does not open into the enclosure14, but passes all the way through it, such that the sensors24remain housed in the enclosure14.

The tubular pipe22is then extended by an output pipe32. This output pipe32is intended to open out downstream of the enclosure14, for example in the downstream pipe19.

The tubular pipe22is, for example, secured to the output pipe32. For example, the tubular pipe22and the output pipe32together form a single pipe in one piece. In a variant, the tubular pipe22is welded to the output pipe32.

According to one variant, the tubular pipe22could be fitted at its downstream end in the output pipe32.

Furthermore, according to this third embodiment, the tubular pipe22is secured to the intake pipe28. For example, the tubular pipe22and the intake pipe28together form a single pipe in one piece. In a variant, the tubular pipe22is welded to the intake pipe28.

According to one variant, the tubular pipe22could be fitted at its upstream end in the intake pipe28.

FIG. 5shows a cooling device10according to a fourth example embodiment. In this figure, the elements that are similar to those of the preceding figures are designated using identical references.

According to this fourth embodiment, the tubular pipe22opens into the enclosure14, like in the first embodiment.

Furthermore, the regulating valve30is housed in the enclosure14. Thus, the regulating valve30is also cooled owing to the air circulating in the enclosure14.

In this example, the regulating valve30is upstream of the flow sensors24. However, in a variant, the regulating valve30could be arranged downstream of the flow sensors24, in particular at the downstream end of the tubular pipe22.

In the described example, the tubular pipe22is secured to the intake pipe28(like in the second embodiment), but in a variant it could be fitted in the intake pipe28(like in the first embodiment).

It will be noted that the disclosure is not limited to the embodiments described above, and could assume various conceivable alternatives.

For example, in a variant of the third embodiment, the regulating valve30could be arranged downstream of the enclosure14, on the output pipe32.

Likewise, in a variant of the third embodiment, the regulating valve30could be arranged in the enclosure14, upstream of the sensors24or downstream of these sensors24.