US-12618349-B2 - Liquid supply device for a motor vehicle

US12618349B2US 12618349 B2US12618349 B2US 12618349B2US-12618349-B2

Abstract

A liquid supply device for a motor vehicle includes: a supply pump intended for pumping liquid from a liquid tank to a liquid consumption device, and a filtration assembly for filtering the liquid pumped by the supply pump. The filtration assembly includes a housing in which a filtration member is housed. The housing forms a siphon connected to a suction inlet of the supply pump and includes an open end intended to open into the liquid contained in the liquid tank such that a path of this liquid in the siphon passes through a high level, which, when the level of the liquid in the tank is below a predetermined threshold, is higher than the level of the liquid in the tank. The filtration member includes a filtration zone in the form of a pocket of filtration material extending vertically into the housing.

Inventors

Rémy BOURGOIN
Younes NEJNAOUI
Damian KRUK
Yanis CHENDOUH

Assignees

PLASTIC OMNIUM ADVANCED INNOVATION AND RESEARCH

Dates

Publication Date: 20260505
Application Date: 20230607
Priority Date: 20220607

Claims (14)

1 . A liquid supply device for a motor vehicle, comprising: a supply pump configured to pump a liquid from a liquid tank to a liquid consumption device, and a filtration assembly configured to filter the liquid pumped by the supply pump, the filtration assembly comprising a housing in which a filtration member is housed, wherein the housing forms a siphon connected to a suction inlet of the supply pump and comprises an open end configured to open into the liquid contained in the liquid tank such that a path of the liquid in the siphon passes through a high level, wherein, when a level of the liquid in the liquid tank is below a predetermined threshold, the liquid in the siphon passing through the high level is higher than the level of the liquid in the liquid tank, wherein the filtration member comprises a filtration zone configured as a pocket of filtration material extending vertically into the housing forming the siphon, and wherein the liquid supply device further comprises a supply pipe extending vertically into the pocket between high and low points of the pocket, a first high end of the supply pipe being connected to the suction inlet of the supply pump and a second low end opening into an interior of the pocket.
2 . The liquid supply device according to claim 1 , wherein a ratio V/h, where V is a volume of the filtration member and h is a height of the filtration member, is between 400 mm 2 and 800 mm 2 .
3 . The liquid supply device according to claim 2 , wherein the ratio V/h is 600 mm 2 .
4 . The liquid supply device according to claim 1 , wherein a distance between the second low end of the supply pipe and a bottom of the pocket is between 10 and 90% of a height of the pocket.
5 . The liquid supply device according to claim 4 , wherein the distance between the second low end of the supply pipe and the bottom of the pocket is 25% of the height of the pocket.
6 . The liquid supply device according to claim 1 , wherein the pocket comprises at least two lateral filtration faces, each lateral filtration face of the at least two lateral filtration faces being arranged facing and at a distance from a wall of the housing.
7 . The liquid supply device according to claim 1 , comprising means for heating the housing forming the siphon.
8 . The liquid supply device according to claim 1 , wherein the supply pump is housed in a casing, the filtration assembly being arranged outside the casing and supported by the casing.
9 . The liquid supply device according to claim 8 , further comprising means for releasably attaching the filtration assembly to the casing.
10 . The liquid supply device according to claim 1 , wherein the liquid is an aqueous solution.
11 . The liquid supply device according to claim 10 , wherein the liquid is an ammonia precursor.
12 . A liquid tank for a motor vehicle, wherein the liquid tank is equipped with the liquid supply device according to claim 1 .
13 . A selective catalytic reduction device for purifying exhaust gases from an internal combustion engine of a motor vehicle, wherein the selective catalytic reduction device comprises the liquid tank according to claim 12 , wherein the liquid is an ammonia precursor.
14 . A motor vehicle, wherein the motor vehicle comprises the liquid tank according to claim 12 .

Description

TECHNICAL FIELD OF THE INVENTION The invention relates to a liquid supply device for a motor vehicle. The invention also relates to a liquid tank for a motor vehicle comprising a liquid supply device according to the invention. Additionally, the invention relates to a selective catalytic reduction device for a motor vehicle comprising a liquid tank according to the invention. Finally, the invention relates to a motor vehicle comprising a liquid tank according to the invention. BACKGROUND ART Already known in the state of the art are liquid supply devices for motor vehicles which are used, for example, to inject an additive solution, in particular an ammonia precursor, into the exhaust line of an internal combustion engine, in order to perform selective catalytic reduction (SCR). This selective catalytic reduction reduces the nitrogen oxides (NOx) emitted by light and heavy-duty vehicles equipped with internal combustion engines, thereby reducing the pollution caused by these vehicles to comply with legislation on nitrogen oxide emissions. Selective catalytic reduction requires the use of a reducing agent, such as ammonia, at a precise concentration level and of high quality. An ammonia precursor, such as urea, is generally used as an additive, and it must be precisely metered and injected into the exhaust gas stream, where it is hydrolyzed before converting nitrogen oxides (NOx) into nitrogen (N2) and water (H2O). To do this, it is necessary to equip the vehicles with a tank containing an additive solution, as well as a device for metering and injecting the desired quantity of additive into the exhaust line. In order to prevent the additive solution injector from becoming blocked with impurities that can be found in the additive solution, it is known to filter the additive solution before it is injected. In the prior art, a filtration member is arranged in the additive tank at the inlet of a supply pump for supplying the additive solution allowing the additive solution to be pumped through the filtration member. Through this arrangement, the additive solution is cleaned of its impurities before it is injected into the exhaust line, upstream of the catalyst for the selective catalytic reduction. This also protects the supply pump from impurities in the aspirated additive solution. After a certain period of use, impurities clog the filtration member. Clogging occurs even faster when the impurities are numerous and large. This is particularly true in highly polluted areas. As the level of clogging increases, the filtration capacity of the filtration member decreases and the filtration flow rate of the liquid through the filtration member falls below the suction flow rate of the supply pump. As a result, the pump draws in all or part of the air, causing the supply pump to lose liquid injection pressure. The result is difficulties in accurately metering the injected additive, and therefore a reduction in the efficiency of selective catalytic reduction. The lower the liquid level in the tank, the more air is sucked in, exposing part of the filtration member to the air. SUMMARY OF THE INVENTION One of the aims of the invention is to reduce the risk of loss of liquid injection pressure in a liquid supply device for a motor vehicle over time. To this end, the invention relates to a liquid supply device for a motor vehicle, comprising: a supply pump intended for pumping liquid from a liquid tank to a liquid consumption device, anda filtration assembly intended for filtering the liquid pumped by the supply pump, the filtration assembly comprising a housing in which a filtration member is housed, in which the housing forms a siphon connected to a suction inlet of the supply pump and includes an open end intended to open into the liquid contained in the liquid tank such that a path of this liquid in the siphon passes through a so-called high level, which, when the level of the liquid in the liquid tank is below a predetermined threshold, is higher than the level of the liquid in the liquid tank, characterized in that the filtration member comprises a filtration zone in the form of a pocket of filtration material extending vertically into the housing forming the siphon. Thus, when the supply pump is primed, it first sucks the air out of the housing forming the siphon. This air suction creates a negative pressure which raises the liquid level in the siphon, immersing the filtration member in the liquid. As a result, at the end of the supply pump priming period, the filtration member is no longer in contact with air or, at the very least, the filtration member remains sufficiently immersed, even when the liquid level in the tank is below the predetermined threshold, to prevent the supply pump from drawing in air during operation. In addition, the immersion of the filtration member remains high, even when the liquid level in the tank is low, effectively limiting the clogging effect of the filtration member, preventing liq