PROCESS CONSISTING IN COOLING AT LEAST ONE COMPONENT, SUCH AS A SENSOR, ARRANGED WITHIN A COMPARTMENT OF AN EXHAUST AFTER TREATMENT SYSTEM OF A VEHICLE

Abstract

The invention relates to a process, consisting in cooling at least one component, such as a sensor, arranged within a compartment of an exhaust after treatment system of a vehicle. The exhaust after treatment system comprises a cooling system that is activated during active regeneration of one or more particulate filters arranged within the exhaust after treatment system compartment and that includes a pipe, for blowing fresh air on the component to be cooled or for extracting hot air present at the vicinity of the component to be cooled, so that said component is protected as a priority against high temperatures during active regeneration periods.

Claims

1. Process consisting in cooling at least one component, such as a sensor, arranged within a compartment of an exhaust after treatment system of a vehicle, characterized in that the exhaust after treatment system comprises a cooling system that is activated during active regeneration of one or more particulate filters arranged within the exhaust after treatment system compartment and that includes a pipe, for blowing fresh air on the component to be cooled or for extracting hot air present at the vicinity of the component to be cooled, so that said component is protected as a priority against high temperatures during active regeneration periods.

2. Process according to claim 1, characterized in that the process comprises a step consisting in blowing a respective jet of fresh air in direction of each component to be cooled.

3. Process according to claim 1, characterized in that the process comprises a step consisting in extracting hot air present at the vicinity of each component to be cooled.

4. Process according to claim 1, characterized in that the process includes a step of adjusting the flowrate of fresh air blown on each component to be cooled or the flowrate of hot air extracted at the vicinity of each component to be cooled.

5. Process according to claim 1, characterized in that cooling takes place only during active regeneration.

6. Process according to claim 1, characterized in that cooling takes place as long as the vehicle engine is on.

7. Process according to claim 1, characterized in that active regeneration consists in introducing a small amount of fuel into an exhaust pipe of the vehicle engine.

8. Exhaust after treatment system of a vehicle, comprising a cooling system capable of carrying out a process according to claim 1.

9. Exhaust after treatment system according to claim 1, characterized in that the cooling system includes a pipe, for blowing fresh air on each component to be cooled or for extracting hot air present at the vicinity of each component to be cooled.

10. Exhaust after treatment system according to claim 1, characterized in that the pipe has a first end forming an air nozzle oriented towards a respective component to be cooled and a second end connected to a source of compressed air, such as an air tank.

11. Exhaust after treatment system according to claim 9, characterized in that the cooling system includes a valve for controlling the air flow inside the pipe, the valve being in an open configuration during regeneration periods and in a closed configuration the rest of the time.

12. Exhaust after treatment system according to claim 1, characterized in that the valve is a proportional valve, typically an electrovalve.

13. Exhaust after treatment system according to claim 9, characterized in that the pipe has a first end located close to the component to be cooled and a second end connected to a suction device, such as a fan.

14. Exhaust after treatment system according to claim 1, characterized in that the cooling system includes a controller for controlling a suction force generated by the suction device, in particular a speed controller for controlling the rotation speed of the fan and/or a valve located within the pipe in between the first end and the second end.

15. Exhaust after treatment system according to claim 8, characterized in that at least one component to be cooled, preferably each component to be cooled, is encased in a protective housing arranged within the exhaust after treatment system compartment.

16. Vehicle, comprising an exhaust after treatment system according to claim 8.

Description

[0019] The invention will be better understood from reading the following description, given solely by way of two non-limiting examples and with reference to the appended drawings, which are schematic depictions, in which:

[0020] FIG. 1 is a side view of a heavy-duty vehicle, in particular a tractor truck,

[0021] FIG. 2 is a perspective schematic view representing a thermal engine of the vehicle of FIG. 1, together with a first embodiment of an exhaust after treatment system according to the invention; and

[0022] FIG. 3 is a perspective schematic view representing the thermal engine of the vehicle of FIG. 1, together with a second embodiment of an exhaust after treatment system according to the invention.

[0023] FIG. 1 represents, in side view, a vehicle which is, in the example, a tractor truck 1. However, in a non-represented alternative embodiment, the vehicle may be different from a tractor truck. For instance, the vehicle may be a light-duty vehicle, a utility vehicle, an autonomous vehicle, a bus, etc.

[0024] The tractor truck 1 includes an Internal Combustion Engine (ICE) 2, preferably a diesel engine, and an Exhaust After Treatment System (EATS) 5 for collecting the exhaust gases of the engine 2 through an exhaust pipe 4. The EATS 5 includes a compartment 6 encasing, among others, a Selective Catalytic Reduction (SCR) system 7 and a Diesel Particulate Filter (DPF) 8 for removing unburned particulates of soot from the exhaust gas. In the example, the compartment 6 is a rectangular box encasing all of the components of the EATS 5. Compartment 6 acts as a heat protective shield, i.e. enables confining the intense heat inside during regeneration periods, in particular during active regeneration periods.

[0025] During regeneration of the DPF 8, and in particular during active regeneration periods, the temperature inside compartment 6 is very high. Typically, in the DPF, temperature is often between 550 C. and 650 C. However, some components of the EATS 5 are sensitive to elevated temperatures. This is in particular the case of actuators or sensors, such as the ones used to measure temperature, NOx level or pressure. It is therefore necessary to protect such components from intense heat that is produced during active regeneration periods of the DPF 8. One sensitive component 10, such as a sensor, is represented on FIG. 2.

[0026] As a reminder, active regeneration consists in introducing a small amount of fuel into the exhaust pipe 4, i.e. into an exhaust stream of the vehicle engine, upstream of the particulate filter(s) 8. Active regeneration can be initiated at any time, in particular when the vehicle is parked or moving at low speed.

[0027] In order to protect component 10 from intense heat during active regeneration, the EATS 5 comprises a cooling system 11. In the embodiment of FIG. 2, the cooling system 11 includes an air nozzle 12 for each component to be cooled. The air nozzle 12 is oriented towards the component 10 so as to orient the air jet directly onto the component 10. Each air nozzle 12 is connected through an air pipe 14 to a source of compressed air 18, such as an air tank. The air nozzle 12 forms a first end of pipe 14.

[0028] Advantageously, the source of compressed air 18 may be common to other air consuming devices of the vehicle, such as the brakes, the suspensions, etc.

[0029] Preferably, the cooling system 11 further includes a valve 16 for controlling the air flow inside the pipe 14. Typically, the valve 16 is in an open configuration during active regeneration periods of the DPF 8 and in a closed configuration the rest of the time. In open configuration, air is blown through the nozzle 12 in direction of component 10, while in closed configuration, no air is blown. Accordingly, in this particular example, cooling takes place only during active regeneration periods. The rest of the time, including passive regeneration periods, the cooling system 11 is not activated.

[0030] Advantageously, a controller 20 is provided for controlling the opening/closing of the valve 16. In the example, valve 16 is an electrovalve, meaning that it is electronically controlled.

[0031] Preferably, the valve 16 is a proportional valve, meaning that the flowrate of blown air can be adjusted during all of the period of active regeneration. By the use of a proportional valve, it is possible to adjust the flowrate between 0% and 100% of a maximum flowrate. Typically, the flowrate can be adjusted by the controller 20 to any percentage of the maximum flowrate. Accordingly, the flowrate of fresh air blown in direction of the component to be cooled 10 can be adjusted. This enables adjusting the flowrate of blown air depending on the pressure level of air inside the air tank. Typically, the flowrate of blown air may decrease proportionally with the pressure in the air tank, meaning that the flowrate is preferably higher when the air tank is full. However, as the pressure in the air tank 18 is permanently maintained by an air compressor between 8 and 12 bar, there is no substantial change in the flowrate.

[0032] FIG. 3 represents an alternative embodiment, wherein the cooling system 11 includes a vent pipe 22 for each component to be cooled, in particular one air pipe 22 for the component 10. Advantageously, a first end 23 of the vent pipe 22 is located close to component 10, while a second end (not shown) of the vent pipe 22 is connected to a suction device 24, such as a fan (or fan module). The process then consists, instead of blowing fresh air, in extracting hot air present at the vicinity of the component to be cooled 10. On FIG. 3, the flow of extracted air is represented by arrow F1.

[0033] In this particular embodiment, cooling takes place as long as the vehicle engine is on. Alternatively, in an alternative embodiment that is not shown, the suction device 24 may also be controlled to function only during active regeneration periods of the DPF 8. In this particular embodiment, a controller, such an electronic control unit, is provided for controlling the activation of the suction device 24.

[0034] In another non-represented alternative embodiment, a controller, such an electronic control unit, may also be provided for controlling the suction force generated by the suction device 24. In particular, the cooling system may include a speed controller (not represented) for controlling the rotation speed of the fan. This enables controlling the flowrate of hot air extracted at the vicinity of each component to be cooled and provides the advantage of adjusting the flowrate depending on the cooling needs reflected by the measures taken by the different sensors located in the EATS, or depending on the cooling system efficiency needs.

[0035] Another embodiment that could enable to adjust the flowrate is the use of a valve (e.g. an electrovalve or a butterfly valve) placed anywhere on the vent pipe 22 in between the first end 23 and the second end connected to the suction device 24.

[0036] An embodiment could also combine the use of a valve within the vent pipe 22 and the use of a speed controller.

[0037] Unlike from what is taught in prior art, the cooling system 11 of FIG. 2 or 3 is activated during active regeneration of the particulate filter 8 arranged within the exhaust after treatment system compartment 6. In the embodiment of FIG. 2, the cooling system 11 includes a pipe 14 for blowing fresh air on the component to be cooled 10, while in the embodiment of FIG. 3, cooling system 11 includes a pipe 22 for extracting hot air present at the vicinity of the component to be cooled. Accordingly, only the component(s) 10 to be cooled is or are refreshed during active regeneration periods. This means that the other components, including the DPF 8, are not cooled. In other words, the component(s) 10 is (or are) protected as a priority against high temperatures during active regeneration periods. This is particularly advantageous because the DPF 8 must remain hot in order not to inhibit the regeneration.

[0038] In the two depicted embodiments, only one component 10 is cooled during regeneration periods. However, in a non-represented alternative embodiment, the process may consist in cooling two or more distinct components of the compartment 6. In such configuration, one air nozzle is provided for each component to be cooled, each air nozzle being oriented towards a respective component to be cooled. Alternatively, one vent pipe is provided for each component to be cooled, a first end of each vent pipe being located close to a respective component to be cooled.

[0039] In another non-represented alternative embodiment, at least one component to be cooled 10, preferably each component to be cooled, is encased in a protective housing arranged within the exhaust after treatment system compartment 6. In this particular embodiment, the end 12 of pipe 14 or the end 23 of pipe 22 enters in the protective housing provided around the component to be cooled.

[0040] The features of the two depicted embodiments and of non-represented alternative embodiments can be combined together to generate new embodiments of the invention.