FR2807472A1 - Control unit for regeneration of diesel engine particle filter uses the readings of a piezo-electric sonar to calculate the amount of additive to inject into the fuel vessel - Google Patents

Abstract

Air inlet (2), exhaust air recirculation (4), turbocompressor (5) and fuel inlet are all controlled by central control unit (17). The same unit can initiate series of fuel injections to regenerate the particle filter. The unit also initiates injection of an amount of additive (16,25) into the fuel vessel (15) determined by the amount of fuel added to the fuel vessel as measured by the piezo-electric sonar (26). A second piezo-electric sonar (27) can be mounted within the additive vessel to monitor its level.

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 particle filter integrated in the exhaust line.

However, the management of its operation 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 into an exhaust line of a diesel engine of a motor vehicle, characterized in that the engine is associated with different members, among which means for admitting air into the engine, means for recycling engine exhaust gas into the engine, a turbocharger, an oxidation catalyst placed upstream of the particle filter in the line of exhaust; 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 particulate filter to lower the temperature of combustion of particles trapped in it, means for acquiring information relating to different parameters of engine operation and the organs associated with it, and means for 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 trigger a regeneration phase of the particulate filter by combustion of the particles trapped therein by initiating a phase of multiple fuel injections into the engine cylinders during their expansion phase, and in this the operation of the means s addition of additive is controlled by control means receiving as input information from a piezoelectric sonar associated with the vehicle's fuel tank, to determine the fuel volume added to it during a filling operation , determine the volume of additive corresponding to inject into the tank and control the addition means accordingly.

The invention will be better understood on reading the description which will follow, given solely by way of example and made with reference to the appended drawing, represents a block diagram illustrating a diesel engine of motor vehicle, and the various organs associated with this one.

This figure 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, which are designated by the general reference outlet, this engine is associated with an exhaust line which is designated by the general reference 3.

means for recycling engine exhaust gas at the inlet thereof are also provided and are designated by the general reference 4. means are then interposed for example between the outlet of the engine means 2 for admitting air into it this.

exhaust line can also be associated with a presser turbocom 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 of general reference sign 6, disposed upstream of a particle filter designated general reference 7, in the exhaust line.

engine is also associated with a common fuel supply system for the cylinders thereof. This system designated by the general reference 8 in this figure and comprises for example injectors with electrical control associated with these cylinders. In the embodiment shown, the engine has a four-cylinder engine and therefore comprises 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 connected to fuel supply means designated by the general reference 14, com taking for example a high pressure pump.

supply means are connected to a signed fuel tank by 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 this.

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 amount 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 general reference 17 in this figure, comprising for example a computer 1 associated with means for storing information and connected at input to different means of acquiring information relating to different operating parameters of this engine and of these members, the computer then being adapted to control the operation of the intake means, recycling means, of the turbocharger and / or of the system supply to control operation of the engine and in particular the torque generated by the latter as a function of the running 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 and 7, and 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 also receives information on the oxygen content of the gases leaving the engine from a proportional Lambda a probe designated by the general reference 24 in this figure, associated with the exhaust line.

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

In particular, this computer is adapted to trigger a particle filter regeneration phase by combustion of the particles trapped therein 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.

Advantageously, the means 4 for recycling the engine exhaust gas at the inlet of the latter comprise a proportional solenoid valve which is controlled by the control means 17 in function in formation delivered by the proportional Lambda probe a 24 to regulate the recycling of d exhaust at the engine inlet, during the re-generation phase of the particulate filter.

This then makes it possible in particular to better control the progress of the filter regeneration by combustion of the particles.

The computer 18 can also be adapted to control the operation of the turbocharger 5 and more particularly its boost pressure setpoint in order to regulate the oxygen content of the gases at the engine inlet.

The operation of the additive adding means is controlled by control means receiving as input information from a zoelectric sonar associated with the vehicle's fuel tank, to determine the volume of fuel added to it during a filling operation, determine the volume of corresponding additive to be injected into this tank and control these addition means accordingly. In fact, a metering pump designated by the general reference 25 in this figure, can be interposed between the auxiliary tank 16 in which the additive is placed and the fuel tank 15 of this vehicle.

operation of this pump is then controlled for example by the control means 17 which form the control means are connected to a piezoelectric sonar designated by the general reference and associated with the fuel tank 15, to determine the volume of fuel added thereto during 'a filling operation of this tank.

from this volume of added fuel, the control means determine the volume of corresponding additive to be injected into this tank and pi lot the dosing pump 25 accordingly.

The volume of additive to be injected must in fact be determined as a function of the quantity of fuel added to the tank in order to maintain the additive content of the latter.

note that another piezoelectric sonar designated by the general reference can also be associated with the auxiliary tank 16 in which the additive is placed, for example to monitor the level thereof.

then conceives that such a structure is relatively simple to plant and to implement while making it possible to obtain good dosing precision for the additive injected into the fuel tank.

Claims (1)

<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) associated with different members, among which - means air intake in the engine, means for recycling exhaust gas from the engine at the inlet thereof, a turbocharger (5), an oxidation catalyst (6) disposed upstream of the filter with particles (7) in the exhaust line; - a common fuel supply system for the engine cylinders, comprising electrically controlled injectors (9,10,11,12), associated with these cylinders, - means 25) 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 therein, - 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 7) for controlling the operation of the intake means, recycling means, of the turbocharger and / or of the supply system for controlling operation of the engine, these means being further adapted to initiate a regeneration phase of the particulate filter by combustion of the particles trapped therein by initiating a phase of multiple fuel injections into the engine cylinders during their expansion phase, and in that the operation of the additive adding means (16,25) is controlled by control means (17) receiving as input information from a piezoelectric sonar (26) associated with the fuel tank (15) of the vehicle, to determine the volume of fuel added to it during a filling operation, determine the volume of corresponding additive to be injected into the tank, control the addition means accordingly. System according to claim 1, characterized in that adding means comprise a metering pump (25) interposed between the fuel tank 5) and an auxiliary tank (16) in which the additive is placed. System according to claim 1 or 2, characterized in that one to the other piezoelectric sonar (27) is associated with the auxiliary tank (16).