FR2804176A1 - System to aid the regeneration of a particulate filter in the exhaust system of a Diesel automotive engine - Google Patents

Abstract

The system has a unit to control the functioning of the air intake unit (2), the exhaust gas recycling unit (3), the turbocompressor (5) and the feed system for controlling the engine, these units adapted to trigger a regeneration phase of the particulate filter by combustion of the particles trapped in the filter, while stopping the multiple fuel injection phase in the cylinders of the engine during their expansion phase. The control unit (17) has members for evaluation of the result of the regeneration phase of the particle filter (7) for triggering a complementary regeneration phase if the result of the regeneration are insufficient.

Description

The present invention relates to a system for assisting the regeneration of a particulate filter integrated in an exhaust line of a diesel engine of a motor vehicle. We know that the reduction of polluting emissions linked to the operation of motor vehicle engines and in particular diesel engines is a permanent concern of manufacturers. Various systems have already been developed in the state of the art to reduce the level of these polluting emissions in particular by using a particulate filter integrated in the exhaust line. However, the management of the functioning thereof and in particular the management of its regeneration still generates difficulties. The object of the invention is therefore to solve them. To this end, the subject of the invention is a system for assisting the regeneration of a particulate filter integrated in an exhaust line of a diesel engine of a motor vehicle, characterized in that the engine is associated with different components, including - means for admitting air into the engine, - means for recycling exhaust gases from the engine at the engine inlet, - a turbocharger, - an oxidation catalyst arranged in upstream of the particulate filter in the exhaust line; - a common fuel supply system for the engine cylinders, comprising electrically controlled injectors, associated with these cylinders, - means for adding to the fuel an additive intended to be deposited on the particle filter for lower the combustion temperature of the particles trapped in it, - means of acquiring information relating to different operating parameters of the engine and of the members associated with it, and - means of controlling the operation of the intake means, recycling means, of the turbocharger and / or of the supply system for controlling the operation of the engine, these means being further adapted to initiate a regeneration phase of the particulate filter by combustion of the trapped particles in this by initiating a phase of multiple fuel injections into the engine cylinders during their expansion phase, and in that the control means comprise means for evaluating the results of a regeneration phase of the particulate filter to trigger an additional regeneration phase if the results of the regeneration are insufficient. The invention will be better understood on reading the description which follows, given solely by way of example and made with reference to the appended drawings, in which - FIG. 1 represents a block diagram illustrating a diesel engine of a motor vehicle , and the different organs associated with it; and - Fig.2 illustrates the evaluation of the results of a regeneration of the filter. FIG. 1 shows a motor vehicle diesel engine which is designated by the general reference 1. This diesel engine is associated with air intake means at the inlet thereof, which are designated by the general reference 2. At the outlet, this engine is associated with an exhaust line which is designated by the general reference 3. Means for recycling the exhaust gas from the engine at the inlet thereof are also provided and are designated by the general reference 4. These means are then interposed, for example, between the outlet of the engine and the means 2 for admitting air into it. The exhaust line can also be associated with a turbocharger designated by the general reference 5 and more particularly with the turbine portion thereof, in a conventional manner. Finally, the exhaust line comprises an oxidation catalyst designated by the general reference 6, disposed upstream of a particle filter designated by the general reference 7, disposed in the exhaust line. The engine is also associated with a common fuel supply system for the cylinders thereof. This system is designated by the general reference 8 in this figure and comprises, for example, electrically controlled injectors associated with these cylinders. In the embodiment shown, the engine is a four-cylinder engine and therefore includes four electrically controlled injectors, respectively 9,10,11 and 12. These different injectors are associated with a common fuel supply manifold designated by the general reference 13 and connected to fuel supply means designated by the general reference 14, comprising for example a high pressure pump. These supply means are connected to a fuel tank designated by the general reference 15 and to means for adding to this fuel an additive intended to be deposited on the particle filter to lower the combustion temperature of the particles trapped in it. In fact, this additive can for example be contained in an auxiliary tank designated by the general reference 16 associated with the fuel tank 15, to allow the injection of a certain quantity of this additive into the fuel. Finally, this engine and the various members which have just been described are also associated with means for controlling their operation designated by the general reference 17 in this figure, comprising for example any suitable computer 18 associated with storage means for 'information 19, and connected as input to different means of acquiring information relating to different operating parameters of this engine and of these members, this calculator then being adapted to control the operation of the intake means, recycling, of the turbocharger and / or of the fuel system to control the operation of the engine and in particular the torque generated by it as a function of the driving conditions of the vehicle in a conventional manner. Thus, for example, this computer is connected to a differential pressure sensor 20 at the terminals of the catalyst and the particle filter, respectively 6 and 7, to temperature sensors 21, 22 and 23, respectively upstream of the catalyst. , between this catalyst and the particulate filter and downstream of this particulate filter in the exhaust line. The computer can also receive information on the oxygen content of the exhaust gases from a Lambda probe a, designated by the general reference 24 in this figure, integrated in the exhaust line.

At the outlet, this computer is suitable for controlling the air intake means, the exhaust gas recycling means, the pressurized turbocom, the means for adding the additive to the fuel, the means for supplying fuel from the common rail and the various injectors associated with the engine cylinders.

In particular, this computer is adapted to trigger a regeneration phase of the particle filter by combustion of the particles trapped in it by initiating a phase of multiple injections of fuel into the engine cylinders during their expansion phase.

The particles emitted by the engine during its operation are in fact trapped in the particle filter. It should then be regenerated regularly by combustion of these particles.

The control means 17 also include means for evaluating the results of a regeneration phase of the particulate filter to trigger, if necessary, an additional regeneration phase, in the event that these results are deemed insufficient.

This can for example be carried out on the basis of the information delivered by the differential pressure sensor 20 placed at the terminals of the particle filter 7.

We know that this differential pressure is linked to the state of charge of particles in the filter.

If after a regeneration phase, this differential pressure has not fallen below a predetermined threshold, it can then be considered that the regeneration of the filter has not been sufficient, to trigger a regeneration phase complementary to it this.

This additional regeneration phase can then be based on hydrocarbon content and exhaust gas temperature values greater than the values normally used during a standard regeneration phase. This phase is of course controlled by the control means 17 and more particularly by the computer 18 by acting on the engine and its various members associated in a conventional manner.

Such an evaluation is illustrated in FIG. 2, in which we recognize, at 25, the acquisition of the information OP at the output of the differential pressure sensor 20 by the computer 18. This information which is in fact an image of the load in particles of the filter 7, are compared at 26, by this computer 18 to a reference value S, stored for example in the storage means 19.

If the particle load of the filter is greater than the reference value S, the control means 17 and more particularly the computer 18 feel that the regeneration of the filter 7 is insufficient and trigger a strategy for controlling the engine and its components associated so as to initiate a complementary regeneration phase as illustrated in 27, in the manner described above.

Claims (3)

<U> CLAIMS </U> 1. A system for assisting the regeneration of a particulate filter integrated into an exhaust line of a diesel engine of a motor vehicle, characterized in that the engine (1) is associated with different members, among which - means (2) for admitting air into the engine, - means (4) for recycling exhaust gases from the engine at the inlet thereof, - a turbocharger (5), - an oxidation catalyst ( 6) disposed upstream of the particulate filter (7) in the exhaust line; - a system (8) for common supply of fuel to the engine cylinders, comprising electrically controlled injectors (9,10,11,12), associated with these cylinders, - means (16) for adding to the fuel an additive intended to be deposited on the particle filter (7) to lower the combustion temperature of the particles trapped in it, - means (20,21,22,23,24) for acquiring information relating to different operating parameters of the engine and of the members associated with it, and - means (17) for controlling the operation of the intake means, recycling means, the turbocharger and / or the supply system to control the operation of the engine, these means being further adapted to trigger a regeneration phase of the particle filter by combustion of the particles trapped therein by initiating a phase of multiple injections of fuel into the engine cylinders during leu r expansion phase, and in that the control means (17) comprise means (18) for evaluating the results of a regeneration phase of the particle filter (7) in order to trigger a complementary regeneration phase (at 27 ) if the regeneration results are insufficient. 2. System according to claim 1, characterized in that the evaluation means (18) comprise means for comparing (at 26) the output information (AP) of a differential pressure sensor (20) arranged at the terminals nes of the filter (7), to a reference value (S) to trigger (at 27) a complementary regeneration phase of the filter if the differential pressure (AP) as measured by the sensor is greater than the reference value (S ). 3. System according to claim 2, characterized in that the reference value (S) is stored in storage means (19) associated with the evaluation means.