RU2605798C2 - Method of regenerating particles filter for motor vehicle - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: invention relates to hybrid vehicles with internal combustion engines. In the method of a particles filter regeneration systems of a hybrid car engine exhaust gases perform regeneration and measure temperature in continuous mode at the particles filter input. Then modes of the car thrust are controlled with breaking the first stop of the engine, if the determined temperature is below the first preset temperature. If the first stop was not braked, the engine is stopped until the temperature at the particles filter input exceeds the second preset temperature depending on the load of the particles filter for the moment of regeneration request.

EFFECT: improved optimization of the regeneration filter and higher comfort of the hybrid car control.

10 cl, 1 dwg

Description

The invention relates to the field of hybrid automobile vehicles equipped with an internal combustion engine with an exhaust gas system containing a particle filter. In particular, the invention relates to the field of methods for removing harmful substances from such vehicles of such automobiles, the internal combustion engine of which is capable of stopping during certain driving phases.

Hybrid cars are equipped with several drive devices that are triggered by alternative energy sources. These alternative energy sources are fuel, gasoline or diesel and electric.

Internal combustion engines using fuel emit solid particles, the removal of which is constantly ensured by a particle filter, which is included in the exhaust circuit. The particle filter is combined with a catalytic device, which is placed at the inlet of the particle filter in the direction of gas circulation. Such a catalytic device is designed to clean the exhaust gases leaving the engine, previously before they enter the filter in which these particles settle. The removal of settled particles is carried out by burning at a temperature of the order of 450 ° C to 750 ° C, while a lower range of less than 550 ° C is possible if the filter is so-called additive, that is, if an additive such as cerine or iron.

Even if the particle filter is additive to obtain such temperatures, and these temperatures are usually higher than the temperature of the exhaust gases of a diesel-type internal combustion engine, resorting to means to increase the thermodynamics of the engine, for example, by calibrating the engine in accordance with special modes of engine operation, such as the initial delay injection and / or adjustment of the intake pressure and / or implementation after injection. The engine load can also be increased when using electricity consumers, the use of which is regulated depending on the need.

A specific problem facing hybrid vehicles is the shutdown of the internal combustion engine that they are equipped with when the hybrid vehicle uses an alternative energy source to operate an auxiliary engine, in particular an electric engine. When the internal combustion engine stops, the temperature in the exhaust system decreases rapidly, and there is no gas in the exhaust system. In the case of an attempt to regenerate the particle filter, it is harmful, since it delays the moment when the burning of particles starts, or it will slow down such burning (when it already started before the heat engine stopped) or it will just stop it. As a result of this, the simplest solution for maintaining regeneration of the particle filter is to prevent the heat engine from stopping if the control unit of the particle filter requires its regeneration.

However, such a decision can cause a “negative” reaction of the driver, who does not understand why his car does not work more like a “hybrid”, in particular, if he presses the “clean electric mode” button. To ensure operation in the electric mode, it is necessary to establish a strategy that minimizes the negative effects of shutting down the heat engine.

To prevent interruption of particle filter regeneration when the engine is stopped, Patent Application FR 2925938 proposed blowing hot air into the exhaust system, combining fuel injection with this operation to maintain an exothermic reaction in the catalyst.

In document EP 0987139, it was proposed to adapt the control of the operation of the additional engine depending on the temperature determined in the catalyst. More specifically, the auxiliary engine provides power, which is adjusted depending on such a determination of temperature, while lowering the temperature of the catalyst causes a decrease in the amount of additional current needed to minimize the assistance supplied to the engine.

From patent application FR 2956878, a particle filter regeneration method is known which comprises an exhaust gas system connected to an internal combustion engine that a hybrid vehicle is equipped with, according to which, if regeneration is in progress, although a request to stop the internal combustion engine is sent after activation alternative drive of the car, continuously determine the temperature at the inlet of the particle filter, compare a certain temperature with a given temperature and prohibit engine shutdown in morning combustion, at least if the determined temperature is below the first predetermined temperature, as long as at least the detected temperature is above a second predetermined temperature value, at which the internal combustion engine stop is permitted.

Thus, if the particle filter is at a temperature exceeding the first predetermined temperature, in other words, if regeneration is in progress, and the thermodynamics of the particle filter are satisfactory, then the heat engine is stopped. On the contrary, when the troubles caused by these stops become very significant, when the temperature at the inlet of the particle filter is very low, you should turn on the heat engine or stop it from stopping.

The objective of the present invention is to improve the method known from patent application FR 2956878 in such a way as to optimize the possibility of regeneration of the particle filter while minimizing the impact on the client and maximally preserve the hybrid mode. In particular, it consists in adapting the regeneration strategy depending on the mass as follows: when the particle filter is lightly loaded with soot, you can afford to have a longer regeneration, but the more the filter is filled with particles, the more short and effective regeneration is required.

This problem is solved by the method of regenerating a particle filter, which contains an exhaust gas system associated with an internal combustion engine with which a hybrid vehicle is equipped, according to which during the regeneration process the temperature at the inlet of the particle filter is continuously determined and the GMF coordinator controlling the vehicle’s traction will hold the first stop of the internal combustion engine, at least if the measured temperature is below the first set temperature (T of the first stop), and if ervaya stop was prohibited, will provide a stop of the heat engine, while the temperature at the particulate filter inlet is above the second predetermined temperature (Tamont FAP), depending on the load of the particle filter when the regeneration request.

It is preferable to distinguish between a first set temperature and a second set temperature, designating a first set temperature for initially prohibiting engine shutdown between the two phases of starting the car, and a second set temperature for allowing stopping the engine when the measured particle filter temperature is sufficient to regenerate it.

In a preferred embodiment of the invention, soot loading is also taken into account for the specific determination of the zone when the traction is provided only by electric means (TEP zone for Traction Electrique Pure), for example, under significant soot loads and a complete travel ban in the TEP zone. In other words, control laws in hybrid mode usually do not depend only on the mode and torque requested by the driver and battery charging, but also on soot loading.

In an embodiment of the invention, the prohibition of stopping the engine depending on the first predetermined temperature depends, in addition, on determining the temperature outside the car and comparing it between this specific outside temperature and the predetermined outside temperature. So, take into account a more or less large volume of outside air for cooling the exhaust system.

The invention also relates to a method for restarting a heat engine, which also takes into account soot loading and, in addition, minimizes the driver’s influence on providing regeneration in good conditions.

So, after stopping the heat engine allowed during the regeneration phase of the particle filter in accordance with an embodiment of the invention, the heat engine is restarted when conditions for restarting are created, taking into account soot loading at the beginning of regeneration. Alternatively, consider the loading of soot at the time of the restart.

In an embodiment, the restart condition is a particle filter inlet temperature lower than the third temperature threshold, called the restart temperature threshold, wherein said restart threshold of said start is adapted to be loaded with soot at the start of regeneration or, in accordance with an embodiment, depending on the soot load at moment of restart.

In the embodiment selected by the restart condition, the maximum allowed stop time of the heat engine can also be set, and this maximum stop time of the heat engine is adjusted depending on the soot loading of the particle filter at the beginning of regeneration or at the time of restart.

Preferably, the input for this maximum duration takes into account the vehicle speed at the moment the heat engine was stopped and the outside temperature, while the soot load is taken as a multiplying factor (less than 1) to reduce this maximum duration.

In an embodiment, the restart condition is the maximum permitted duration for the regeneration phase, wherein said maximum duration for regeneration depends on soot loading at the start of regeneration or at the time of the restart.

When the restart of the heat engine is called up to verify the reliability of one of the restart conditions indicated above, it is preferable to choose the second level of regeneration maintenance for the method, in other words, if there are two levels of regeneration maintenance, then the second level, which creates great difficulties for consumption, is immediately selected a level of great difficulty (but also more effective). For these various levels of the method, a threshold is used, in particular, in patent EP 1281852, which describes specific injection methods for the regeneration phases of the filter of particles of level 1 and level 2 (these methods of levels 1 and 2 are, of course, different from methods carried out outside the regeneration phases )

However, when restarting the engine, it is preferable to resort to the activation request of electrical consumers (which cause an increase in engine thrust and, thus, exhaust gas temperature), while the activation request can be stopped when the temperature at the inlet of the particle filter reaches the upper critical temperature for activation electrical consumers. In addition, it is also possible to use a method for loading a car battery that will be stopped when the temperature at the inlet of the particle filter reaches the upper critical temperature value for the method of recharging the battery, while the upper critical temperature values are specified depending on the soot loading at the beginning of regeneration or moment of restart.

In accordance with the detailed description of the method proposed in the present invention, as soon as the regeneration of the particle filter is turned on, the controller of this regeneration (called the FAP supervisor) informs the GMF coordinator, the first role of which is to select the operation mode “heat engine only”, “electric motor only” or mixed mode depending on the mode request by the driver (depending, for example, on the degree of pressing the accelerator pedal) and the required electric load.

This information delays the transition to electrical mode under certain conditions.

Thus, the temperature at the inlet of the particle filter is continuously determined (called the inlet temperature with respect to the direction of gas circulation in the exhaust system), a certain temperature is compared with the first threshold temperature and the stop of the internal combustion engine is prohibited, at least if the certain temperature is less than the first threshold temperature T the first stop, called the Tamont FAP threshold, the delay of the first stop.

If the engine stop has not been delayed, the next engine stop request can be made as soon as the temperature at the inlet of the particle filter does not fall below the limit value of the regeneration feasibility (second threshold temperature) of the Tamont FAP. It should be recalled that the GMF supervisor will constantly search for the requested moment mode when optimizing vehicle consumption, and that, therefore, even if the first stop was allowed, it will not necessarily be performed by the GMF supervisor if, for example, the requested torque at a given time is too great.

If, after the temperature drops below this second threshold value, the temperature at the FAP input rises above this limit value, then the engine stop is allowed again.

This second threshold temperature is specified depending on the mass of soot present in the particle filter. The higher the soot load, the higher the threshold. For example, this threshold could be 400 ° C when the particle filter load is below its nominal load (nominal load means the load below which regeneration is not turned on), 430 ° C when the soot load is nominal, and 460 ° C as soon as soot mass of 1.5 will exceed this nominal value.

The auxiliary engine remains on and the particle filter regeneration conditions are fulfilled, while stopping the internal combustion engine is permitted. Such satisfactory conditions correspond, in particular, to a suitable particle filter temperature with respect to the second threshold temperature, preferably taking into account the external temperature and / or speed measured during the initialization of the particle filter regeneration operation. More precisely, the temperature of the particle filter is sufficient when compared with the second threshold temperature, which corresponds to the boundary value of the feasibility of regeneration, while the car moves only with the help of an additional engine. The use of only an additional engine is, however, adapted from a coordinator who uses a predetermined and specific area of pure electric traction (TER) to the phases of the regeneration of the particle filter with specific retention points. This adaptation of the TEP zone takes into account not only the regeneration of the particle filter, but also the soot loading of the particle filter: the more soot in the filter, the more the TEP zone will be reduced. For example, this TER zone could be zero as soon as the soot load exceeds 1.5 times the nominal value.

Preferably, the prohibition of engine shutdown, depending on the first threshold temperature, is further dependent on the definition of the external environment surrounding the vehicle and the comparison of this external determined temperature and the external set temperature. Thus, more or less large volumes of outside air are taken into account for cooling the exhaust system.

When allowing the engine to stop, several specific criteria are provided for the repeated forced start of the internal combustion engine after the coordinator's command to stop it. These specific criteria themselves depend on the soot load and correspond, for example, to the three following options:

- if the measured temperature at the inlet of the particle filter is lower than the third restart threshold, called the start temperature, the input start threshold T, that is, the restart of the internal combustion engine, is forced. The value of the Tamont FAP restart threshold is adapted for soot loading with FAP: the more particles there are in the filter, the higher the threshold. For example, this threshold could be fixed at 390 ° С, when there are no particles in the FAP, at 420 ° С, when there is no nominal soot loading, and 450 ° С, as soon as the mass of soot exceeds 1.5 times the nominal value;

- if the stop of the internal combustion engine is carried out in the process of the first specified duration, which is very long, then the TER work is considered as very long due to comparison with the indicated first duration, and in order not to complicate the cases of effective regeneration of the particle filter, it is necessary to restart internal combustion engine. This possible option corresponds mainly to safety in the event that the information provided by the temperature sensor at the inlet of the particle filter would be incorrect without the sensor itself not to be faulty. This predetermined duration is preferably read from cartography depending on the vehicle’s speed, on the one hand (speed at the moment when the engine is stopped), and ambient temperature, on the other hand, since these two parameters affect the cooling rate of the exhaust system. In addition, this mapping is preferably adjusted depending on the mass of soot present in the particle filter: the more particles in the filter, the shorter the maximum stopping time. For example, this threshold could be 1 minute when there are no particles in the FAP, 45 seconds when there is a nominal soot load, and 20 seconds when the soot mass exceeds the minimum value by 1.5 times;

- if the regeneration request lasts too long, the heat engine restarts and the internal combustion engine runs continuously until the regeneration is over or when the driver breaks the contact. This maximum regeneration duration follows from the curve of the percentage of soot already regenerated, while the percentage of soot already regenerated is calculated continuously according to the FAP supervisor and adapts depending on the mass of soot present in the particle filter: the more soot particles in the filter, the shorter duration. For example, this threshold could be 10 minutes when the soot load is less than the nominal value, 8 minutes when there is a nominal soot load, and 5 minutes as soon as the soot load is 1.5 times the nominal value.

It should be noted that regeneration at nominal mass can begin to take place when the driving conditions are favorable in relation to the conditions of the “normal” movement of the driver, taking into account his driving history.

When the request to restart the engine is completed, the GMF coordinator starts the heat engine again. Thus, the most adapted control method of control should be selected.

It is advisable that when a restart is requested after evaluating the conditions for restarting, the heat engine is put into an increased regeneration mode for immediate transfer to the regeneration process without delay.

When the regeneration of the particle filter has begun, the corresponding electrical consumers with which the vehicle is equipped are also activated. By appropriate electrical consumers is meant electrical means that are directly involved in the regeneration (for example, heating means), but especially available means that are not controlled by the driver, the inclusion of which will create an increase in torque and, thus, indirectly, the temperature of the exhaust gases. These available means are, for example, electrical resistances (such as a heated front window or a heated rear window).

When the required temperature conditions for the particle filter are reached, electrical consumers are turned off to minimize vehicle consumption. When conditions worsen, electrical consumers can be switched back on.

The disconnection of electrical consumers is preferably carried out as soon as the temperature at the inlet of the particle filter reaches the upper critical level for switching on electrical consumers.

This critical temperature level for switching on the electrical consumers, after which the switching on of the electrical consumers is delayed, preferably depends on the soot loading of the particle filter. For example, this threshold could be set at 500 ° C, when the load is less than the nominal load, at 520 ° C, when the soot load is nominal, and at 550 ° C, as soon as the soot mass exceeds 1.5 times the nominal value.

The inclusion, on the contrary, can be requested again if the temperature at the inlet of the particle filter drops below the lower threshold, which can be selected depending on the soot loading of the particle filter, for example, set to 460 ° C, when there are no particles in the FAP, at 480 ° C when the soot loading is nominal, and at 500 ° C, as soon as the soot mass exceeds 1.5 times the nominal value.

Complementing or replacing the method of turning on electrical consumers, it is also possible to provide a method of charging the battery.

An example of a method for charging a battery is shown in FIG. 1, which depicts a weather forecasting method as described in patent application FR 2952974.

At the first stage A, the amount of accumulated energy Estock in the electric storage device is determined. We are talking about the amount of energy transmitted to an electric storage device to ensure full charge. This amount of stored energy 1 depends on the charge level of the drive at the time of determination, but may also depend on environmental factors such as the outdoor temperature or the internal temperature of the drive.

At the second stage B, the power P1 supplied to the drive for supplying its stored energy Estok for a predetermined time Tmini is determined.

In the comparison step C, the supplied power P1 and the minimum predetermined power Pmini are compared.

Pmini and Tmini are values that can be determined in the engine control device and can be adapted depending on the use in question (the location of the particle filter relative to the engine, the length of the exhaust system, etc.). When used in a classic car, the duration Tmini, necessary for the engine load to have a significant effect on the temperature of the gases at the inlet of the particle filter due to the thermal inertia of the exhaust, is from 120 to 180 seconds.

If the power P1 intended for supply is greater than or equal to the minimum power Pmini, power P1 is supplied to the drive for a given duration Tmini at the stage of increasing the load of the heat engine D.

If the power P1 intended for supply is lower than the minimum power, the minimum power Pmini is supplied to the drive for a duration that allows the drive to be fully charged at the stage of minimizing the load of the heat engine E.

In the framework of the present invention, when the temperature at the inlet of the particle filter reaches the upper critical temperature for the method of charging the battery, the method slows down. This temperature ceiling preferably depends on the soot loading of the particle filter.

For example, this ceiling can be installed at 480 ° C to load soot less than the nominal load, at 500 ° C for nominal soot loading and at 550 ° C with soot amount exceeding 1.5 times the nominal value.

On the contrary, the activation of the method will begin if the temperature at the inlet of the particle filter drops below the lower limit for the method of charging the battery. This lower threshold value may also depend on the soot loading of the particle filter.

For example, this lower limit can be set at 450 ° C for soot loading less than the nominal load, at 460 ° C for nominal soot loading and at 500 ° C as soon as the soot mass is 1.5 times higher than the nominal value.

It should be noted that, in addition, it is preferable to provide a muted version in the event of a malfunction in measuring the temperature at the inlet of the particle filter or the outside temperature. In this case, engine shutdown methods can no longer be used. So, if a request for regeneration is received, although one of the sensors is faulty, the heat engine will continue to operate normally, despite the presence of malfunctions. Any shutdown of the heat engine will be prohibited, and operation in purely electric mode will be impossible.

The method proposed in the present invention, allows to optimize the operation of the regeneration of the particle filter with a total minimized duration. The best energy efficiency is obtained when the internal combustion engine works simultaneously with the operation of the additional engine only if the vehicle controls, in particular, a computer or coordinator, based on the measurement of the particle filter temperature, carried out continuously in real time. The engine load during the restart phases causes an instantaneous reduced dilution of the fuel in the oil. The driver receives the phases of the car’s movement only from the additional engine, and it is allowed to stop the internal combustion engine during the regeneration of the particle filter. Electric consumers are switched off depending on the measurement of the particle filter temperature, as soon as an increase in car consumption is ensured. The regeneration of the particle filter is effective regardless of the state of loading of the latter with selective activation of the vehicle’s energy resources, which is adapted to reduce energy losses.

Claims (10)

1. A method for regenerating a particle filter, including an exhaust system connected to an internal combustion engine that a hybrid car is equipped with, according to which the particles are regenerated and continuously measured at the inlet of the particle filter and the vehicle’s traction modes are controlled by the GMF coordinator, which allows you to slow down the first stop of the internal combustion engine, at least if the detected temperature is lower than the first set temperature (T of the first stop), and if the first the stop was not braked, the heat engine is authorized to stop until the temperature at the inlet of the particle filter exceeds the second set temperature (Tamont FAP), which depends on the load of the particle filter at the time of the regeneration request. 2. The method according to p. 1, characterized in that the first set temperature and the second set temperature are distinguished, with a first set temperature for initially inhibiting the internal combustion engine between the two phases of restarting the car, and a second set temperature for allowing the engine to stop when the measured temperature particle filter is satisfactory in terms of its regeneration. 3. The method according to one of the preceding paragraphs, characterized in that the said prohibition of engine shutdown depending on the first predetermined temperature depends, in addition, on determining the temperature outside the car and comparing between this outside temperature and the upper set temperature. 4. The method according to p. 1, characterized in that after an allowed shutdown of the heat engine during the regeneration phase of the particle filter, the restart of the heat engine is forced when certain conditions for restart are met, while the above conditions take into account soot loading at the start of regeneration or at the time of repeated start up. 5. The method according to p. 4, characterized in that the condition for restarting is the temperature at the inlet of the particle filter, lower than the third temperature threshold, called the threshold temperature of the restart, and the said threshold temperature of the launch is adapted depending on the soot load when starting regeneration or at the time restart 6. The method according to p. 4, characterized in that the condition for restarting is the maximum stopping time of the heat engine, while the maximum duration is adjusted depending on the soot loading of the particle filter at the start of regeneration or at the time of restart. 7. The method according to p. 6, characterized in that the said duration of the engine stop before correction depends on the speed of the car at the moment when the heat engine was stopped, and on the temperature outside the car. 8. The method according to p. 4, characterized in that the condition for restarting is the maximum permitted duration of the regeneration phase, while the mentioned maximum duration depends on the soot loading at the start of regeneration or at the time of restarting. 9. The method according to p. 4, characterized in that when a restart is requested as a result of checking the conditions for restarting, the heat engine is started in accordance with the regeneration of the increased level. 10. The method according to p. 4, characterized in that when the restart is carried out according to the results of evaluating the restart conditions, the electrical consumers and / or the battery charging method are activated, said activation stops when the temperature at the inlet of the particle filter reaches the critical temperature ceiling to activate the electrical consumers or ceiling critical temperature for the method of charging the battery, while the above-mentioned upper values of the critical temperature are specified depending on the soot load when starting regeneration walkie-talkie or at the time of restart.

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