FR2927657A3 - Fuel i.e. diesel oil, supply system for exhaust gas depollution device of e.g. diesel engine, of motor vehicle, has branch provided on supply line of engine, in upstream of high pressure pump and formed in downstream of electric pump - Google Patents

Abstract

The system has a branch (21) provided on a supply line of an engine of a motor vehicle, in upstream of a high pressure pump (3). The branch on the supply line is formed in the downstream of an electric pump (2) supplying the high pressure pump and speed reducers addition system. A pressure limiter (4) is provided at an output of the electric pump. A measuring module (5) is provided in an upstream of the addition system, and a check valve (9) is provided in the upstream of the addition system. An independent claim is also included for an exhaust gas de-pollution device comprising speed reducers addition system.

Description

FUEL SUPPLY OF THE INTAKE REDUCER INTAKE SYSTEM AND EXHAUST GAS DELETION DEVICE OF A MOTOR VEHICLE

DESCRIPTION

TECHNICAL FIELD The invention relates to the field of motor vehicles, in particular the depollution relating to the use of diesel engines. In a vehicle, it concerns both the intake system of reducers in the exhaust gas consumed by the engine and the supply of the high pressure pump fueling the engine.

PRIOR ART AND PROBLEM POSE To meet the lower thresholds for emissions of polluting gases from motor vehicles, increasingly complex gas after-treatment systems have been provided, especially in the exhaust gas line. consumed in lean-burn engines. These make it possible to reduce emissions of particulate matter and nitrogen oxide in addition to carbon monoxide and burned hydrocarbons. Unlike a traditional oxidation catalyst, these systems operate discontinuously or alternatively, that is to say, in normal operation, they trap pollutants but only treat them during successive regeneration phases. Thus, to be regenerated, this trap requires specific modes of combustion, to ensure the level of thermal quality and / or wealth necessary for this operation.

On the other hand, in order to meet the future European EURO5 regulations, internal combustion engines of the diesel type must be developed in order to produce the least amount of exhaust emissions, the rest to be converted by exhaust aftertreatment systems. Because of their specific operation, diesel engines emit soot in their exhaust gases, which they also call particles. In order to limit the emissions of these soot particles into the atmosphere, a filter is located in the exhaust line downstream of the combustion chambers of the engine. This filter retains the particles that accumulate within it, as and when the engine is used.

Internal combustion engines also emit reducers including carbon. In the presence of oxygen, catalytic materials such as platinum and at high temperature, these reducing agents oxidize. In order to reduce these pollutant emissions, there is also in the exhaust line, either an oxidation catalyst upstream of the particulate filter, or directly catalytic material within the filter and then called catalytic particle filter. Accumulation of the particles eventually clogs the filters creating a strong back-pressure to the engine exhaust, which significantly reduces its performance. In order to find these, it is common to burn the particles in the particulate filter, this procedure called regeneration of the particulate filter. The initialization and the maintenance of the combustion of the particles in the filter are obtained by the elevation of internal temperatures of this particulate filter.

In order to obtain the thermal conditions necessary for the particulate filter, the depositor uses the catalyst placed upstream of it and achieves a rise in temperatures by a supply of reducing agent, making an exothermic reaction in this catalyst.

Currently, there are several strategies to bring these reducers. A known solution to perform the regeneration of the particulate filter is to make late injections with the main injection system of the engine. These injections do not burn in the cylinder but provide reducing agents to the catalyst. Currently, the problem of dilution is treated by a specific request made by the customer by means of a light of the dashboard of the vehicle asking him to put in favorable conditions to regenerate the particulate filter. This causes many problems in the after-sales service of the vehicles, because the customers do not understand well this necessity and / or request. A company policy is to delete this request or this step to be made by the customer. On the other hand, several feed modes of the reducer feed system exist. Patent Application EP 1 643 092 A1 describes a fuel supply of the vaporization system by the use of an additional volumetric electric pump. The latter uses the fuel in the tank and then feeds it into the fuel system, the amount of fuel delivered depends on the pump's driving frequency. In addition, in the French patent application FR 2 879 241, a fuel supply is described by the fuel supply network of the high pressure pump of the vehicle. A stitching is therefore performed in the low pressure stage of the high pressure pump and is used to supply the supply circuit. The objective of the present invention is to reduce the risk of dilution, during a regeneration of the particulate filter.

SUMMARY OF THE INVENTION In order to achieve the above-mentioned objective, the main idea according to the invention is to provide the reducers with the exhaust system directly and no longer by the main injection system. For this purpose, a first main object of the invention is a fuel supply system capable of supplying a system for adding reducers in an exhaust line comprising a stitching on a supply line of a combustion engine. motor vehicle upstream of a high pressure pump. According to the invention, the stitching on the supply line is performed downstream of an electric pump thus supplying both the high pressure pump and the gear reducer addition system. The preferred embodiment of the invention provides the use of a pressure limiter at the outlet of the electric pump.

It is also interesting to use a dosing module at the inlet of the gearbox additive system. The use of a non-return valve upstream of the gearbox addition system is also very useful. A second main object of the invention is a device for cleaning up the exhaust gases of an internal combustion engine. According to the invention, it comprises a device for adding reducers in an exhaust line fed by a fuel supply system as summarized above. The invention is advantageously applied in the case where the additive reductant system is a vaporizer comprising a heating element placed in a vaporization chamber and comprising an outlet pipe with a lateral outlet.

LIST OF FIGURES The invention and its various technical characteristics will be better understood on reading the following description accompanied by two figures respectively representing: FIG. 1, a characteristic diagram of the supply and depollution systems according to the invention, and FIG. 2, a preferred embodiment of the pollution control system in the form of a vaporizer.

DETAILED DESCRIPTION OF THE EMBODIMENT OF THE INVENTION In FIG. 1, the system for adding reductants 1 to the exhaust gas depollution device of an internal combustion engine is placed on the exhaust line of the gases symbolized. by a muffler 6. The reducer comprises in fact, a fuel vaporizer 10 fed by a check valve 9. According to the invention, an electric pump 2 is used to supply fuel to both the high pressure pump. 3 used to supply fuel to the internal combustion engine of the vehicle and the addition of gearbox system 1 used on the exhaust gas line. On an output 22 of the electric pump 2, intended to feed the high pressure pump 3, is a stitching 21 supplying the pressure reducer 4. The latter may be constituted either by a calibrated restriction, for example a cylindrical hole or a passage in a thin layer between two cylinders, or by a pressure regulator type clipper without return.

The supply system is thus completed by a feed line 8 issuing from the pressure limiter 4 and on which is placed a dosing module 5. This can be constituted either by a gasoline injector remotely installed on this supply line 8, or by a proportional solenoid valve. The output of this feeder feeds the gear reducer 1 addition system, that is to say directly the inlet of the check valve 9. It is noted that the pressure limiter 4 can also be a component integrated in the module. 5. Another solution is that the pressure limiter is integrated in the dosing module to constitute a single component. A shutoff solenoid valve can also be added to the supply circuit. In case of failure of the dosing module, this solenoid valve can be closed, to avoid the continuous flow to the vaporizer. Figure 2 shows in detail an embodiment of the vaporizer 10 used in the depollution device. It mainly comprises a fuel inlet 11 opening into a vaporization chamber 13 in which is placed a heating element 12, namely an electric heating element of the resistive type. This assembly allows the contact between the fuel and the heating element. The fuel thus passes in a gaseous form and the increase in pressure pushes it towards an outlet pipe 14 which enters the pipe of the gas exhaust line and can escape through a lateral outlet 15.

In the supply system according to the invention, the supply line is constituted by an electric pump 2 for supplying a fuel distribution network under pressure. The pressure of this network is between 1 and 7 bar relative. This network thus supplies the high-pressure part of the high-pressure pump 3 and the supply line 8 of the system for adding reducers to the exhaust.

In the case of the use of a vaporizer 10, the dosage is preferably carried out by a fuel type MPI injector for controlling the fuel flow rates as a function of its opening time. The vaporizer 10 is made of mechanically welded metal parts and the heating element 12 is a metal glow plug. In the case of the use of an injector at the exhaust, the circuit optionally comprises a shutoff solenoid valve, a limiter / pressure reducer. The dosage is then performed by the exhaust injector itself. The advantage of the solutions proposed according to the invention, compared with the solutions described in the prior art, in particular in the patent document EP 1 643 092, resides in the suppression of a second circuit between the electric pump and the fuel tank. as well as the low pressure stage of the high pressure pump. This represents a significant financial gain. The interest compared to the solution proposed in the French patent application FR 2 879 241 lies in the removal of the stitching at the outlet of the transfer pump. Indeed, this stitching can cause a spreading of diesel in case of accident of the vehicle. In addition, clever piloting of the dual-function electric pump makes it possible to manage the flow according to needs, whether or not in the regeneration phase of the particulate filter.

Claims (6)

A fuel supply system adapted to supply a system for adding gear units (1) in an exhaust line comprising a stitching (21) on a supply line of a motor vehicle engine upstream of a high-pressure pump (3), characterized in that the stitching on the supply line is carried out downstream of an electric pump (2) thus supplying both the high-pressure pump (3) and the adjunct system gearboxes (10). 2. fuel supply system according to claim 1, characterized in that it comprises a pressure limiter (4) at the output of the electric pump (2). 3. fuel supply system according to claim 1, characterized in that it comprises a metering module (5) upstream of the gear reducer addition system (10). 4. Fuel supply system, characterized in that it comprises a non-return valve (9) upstream of the gear reducer addition system (1). 5. Exhaust gas pollution control device of an internal combustion engine characterized in that it comprises a device for adding reducers (1) in an exhaust line fed by a fuel supply system according to the invention. one of the preceding claims. 6. Exhaust gas depollution device according to the preceding claim characterized in that the system of adding reducers (1) is composed inter alia of a vaporizer (10) itself comprising a heating element (12) placed in a spray chamber (13), an outlet pipe (14) provided with a lateral outlet (15).