FR2804168A1 - System for aiding the regeneration of the particulate filter in the exhaust system of a Diesel automotive vehicle engine - Google Patents

Abstract

The system has a unit (17) for controlling the functioning of the air inlet unit (2), and unit for exhaust gas recycling (4), a turbocompressor (5), and a feed system for controlling the functioning of the engine, these units adapted for triggering a regeneration phase of the particulate filter by combusting the particles trapped in the filter, and stopping a multiple fuel injection phase in the motor cylinders during the expansion phase. The control unit has a comparison unit (18) for comparing the exit temperature of the catalyst (6), which is sensed by a temperature sensor (22), to a threshold safe value (S), for regulating the functioning of the engine in order to avoid this temperature exceeding this threshold.

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 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 gas from the engine at the inlet to it, - a turbocharger, - an oxidation catalyst placed upstream 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 to lower the combustion temperature of the particles trapped therein, - means for acquiring information relating to different operating parameters of the engine and of the members associated with it, and - means for controlling the operation of the means intake, recycling means, turbocharger and / or supply system to control engine operation, these means being further adapted to trigger a regeneration phase of the particulate filter by combustion of the particles trapped in it ci by initiating a phase of multiple fuel injections into the engine cylinders during their expansion phase, and in that these means control devices include means for comparing the temperature at the outlet of the catalyst, delivered by a temperature sensor corresponding to a safety threshold value, for regulating the operation of the engine in order to prevent this outlet temperature of the catalyst from exceeding this threshold.

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 a part of regulation of the operation thereof.

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 output, 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 engine outlet and the intake means 2 of in this one.

The exhaust line can also be associated with a pressurized turbocharger designated by the general reference 5 and more particularly with the turbine portion thereof, in a conventional manner.

Finally, the exhaust line includes an oxidation catalyst designated by the general reference 6, disposed upstream of a particulate filter designated by the general reference 7, 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 comprises four electrically controlled injectors, respectively 9, 10, 11 and 12.

These different injectors are associated with a common fuel supply rail designated by the general reference 13 and connected to fuel supply means designated by the general reference 14, including 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 for 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 of 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 temperature sensor 22 placed between the catalyst 6 and the particle filter 7 delivers to the control means 17 and more particularly to the calculator 18, information on the temperature of the catalyst at the outlet thereof.

The computer 18 then compares this temperature at the outlet of the catalyst to a safety threshold value to regulate the operation of the engine in order to prevent the temperature at the outlet of the catalyst from exceeding this safety threshold.

This avoids any degradation of the catalyst.

The control of the operation of the engine is carried out in a conventional manner to regulate this temperature.

This is illustrated in FIG. 2, in which there is illustrated at 25, the acquisition of the temperature at the outlet of the temperature sensor 22, by the control means 17 and more particularly the computer 18. This computer 18 then compares this temperature at a safety threshold value S, at 26, to regulate if necessary at 27, the operation of the engine and of the members associated with it in order to prevent this temperature from increasing too much and causing degradation of the catalyst by exceeding the safety threshold.

 This safety threshold value S can for example be stored in the storage means 19 associated with the computer 18.

Claims (2)

<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 particulate filter by combustion of the particles trapped therein by initiating a phase of multiple injections of fuel into the engine cylinders during the ur expansion phase, and in that the control means (17) comprise means (18) for comparing the temperature at the outlet of the catalyst (6), supplied by a corresponding temperature sensor (22), to a value safety threshold (S), to regulate (at 27) the operation of the engine in order to prevent this catalyst temperature from exceeding this threshold. 2. System according to claim 1, characterized in that the temperature sensor (22) is arranged between the catalyst (6) and the particle filter (7) in the exhaust line.