WO2024156944A1

WO2024156944A1 - Method for regenerating a particulate filter of a hybrid vehicle

Info

Publication number: WO2024156944A1
Application number: PCT/FR2023/051911
Authority: WO
Inventors: Simon MICHAUT; Yohan MILHAU; Herve Delavier; Pascal Folliot
Original assignee: Stellantis Auto Sas
Priority date: 2023-01-27
Filing date: 2023-12-04
Publication date: 2024-08-02
Also published as: FR3145378A1

Abstract

One aspect of the invention relates to a method (100) for regenerating a particulate filter of a hybrid vehicle, comprising the steps of: - determining (101) the maximum torque that can be supplied by a rotating electrical machine; - determining (102) a loss torque of a heat engine when the heat engine is in fuel cut-off; - determining (103) the minimum torque that can be requested by a driver; - determining (104) a torque requested by a driver; and, if the maximum torque that can be supplied by the rotating electrical machine can compensate for, on the one hand, the loss torque plus the minimum torque and, on the other hand, the loss torque plus the requested torque, producing (105) fuel cut-off in the heat engine; and providing (106) the requested torque by means of the rotating electrical machine.

Description

DESCRIPTION

TITLE OF THE INVENTION: METHOD FOR REGENERATING A HYBRID VEHICLE PARTICLE FILTER

The present invention claims priority from French application 2300775 filed on 01/27/2023, the content of which (text, drawings and claims) is herein incorporated by reference.

[0001] One aspect of the invention relates to a process for regenerating a hybrid vehicle particle filter. Another aspect of the invention relates to a hybrid vehicle arranged to carry out the steps of the method.

[0002] The invention finds a particularly interesting application in the field of motor vehicles with electric hybridization, that is to say comprising a thermal engine and at least one rotating electric machine associated with a power battery.

[0003] The invention intends to propose a solution for optimally managing the regeneration of particle filters placed in the exhaust line of the combustion gases emitted by the thermal engine of a hybrid vehicle.

[0004] Automobile manufacturers strive to reduce or even eliminate pollution from their vehicles by different means, for example by reducing fuel consumption and/or by filtering exhaust gases.

[0005] Particulate filters were then developed and are now fitted to more and more vehicles, whether with gasoline or diesel engines. These filters, catalyzed or not, are generally made up of cylindrical ceramic blocks forming a multitude of parallel channels of small diameters (of the order of ten microns). The exhaust gases pass through the filter and the particles they contain are trapped in the channels. These particle filters work correctly but have the disadvantage of having to be regenerated regularly to eliminate the particles which tend to clog the filter channels.

[0006] The elimination of particles is generally carried out by combustion by heating the filter. When the temperature of the particle filter reaches a threshold, and in presence of oxygen, then the particles will burn and the filter will discharge the particles.

[0007] For a conventional motor vehicle, that is to say with a thermal engine only, when the particle filter is sufficiently loaded, strategies for controlling the thermal engine intervene to increase the temperature of the filter via, for example, a degradation of combustion of the heat engine in order to release more thermal energy to heat the filter. Once the particle filter is hot, that is to say when it has reached or exceeded its regeneration threshold temperature allowing the combustion of the particles, the supply of oxygen is made either during the deceleration phases depending on a request for driving power from the driver, either by injecting a mixture lean in fuel, therefore rich in oxygen, or by injecting air into the exhaust line by specific means. In a hybrid motor vehicle, for example comprising an electric engine that does not release the heat of a thermal engine, the torque contribution from the electric engine has the effect of reducing the frequency of life situations allowing the regeneration of the particle filter as envisaged in a conventional motor vehicle.

[0008] We know for example from document FR-B1 -3077341 a method for controlling the regeneration of a particle filter of a vehicle with a hybrid engine proposing a plurality of strategies for controlling the regeneration of the particle filter combining control of a heat engine with an electric motor. However, during a regeneration phase, when the electric motor is saturated, the heat engine is called upon to satisfy the driver's torque demand. In such a situation, the thermal engine is not in injection cut-off, and its torque is equal to the difference between the torque provided by the electric motor and the torque requested by the driver. This operating point is not optimal because the heat engine provides little torque, and the energy consumed by the electric motor is maximum.

[0009] The aim of the invention is to overcome the drawbacks of the prior art by proposing a process for regenerating a hybrid vehicle particle filter making it possible to avoid positioning the heat engine at a non-optimal torque point. to regenerate the particle filter. [0010] In this context, the invention thus relates, in its broadest acceptance, to a process for regenerating a hybrid vehicle particle filter, the process being remarkable in that it comprises, when the filter particle comprises a particle rate greater than a first threshold particle rate and a temperature greater than a threshold temperature, the steps, executed by vehicle control means, of:

Determine a maximum torque that a rotating electrical machine of the vehicle can provide;

Determine a pair of losses of a vehicle engine when the engine is in injection cut-off;

Determine a minimum torque that a vehicle driver can request;

Determine a torque requested by a driver of the vehicle;

If the maximum torque that the rotating electrical machine can provide is able to compensate, on the one hand, the torque of losses added to the minimum torque and, on the other hand, the torque of losses added to the requested torque;

Control an injection cut-off of the thermal engine; And

Provide the requested torque using the rotating electric machine.

[0011] Thanks to the method according to the invention, before controlling an injection cut-off of the heat engine, it is ensured that the rotating electric machine is able to compensate, on the one hand, for the loss torque of the heat engine supplied by the thermal engine when it is in injection cut-off to which we add the minimum torque that the driver of the vehicle can request when letting go and, on the other hand, the torque of losses of the thermal engine to which we adds the torque currently requested by the driver. Thus, if the torque requested by the driver does not change, we are certain that the rotating electric machine is able to satisfy the driver's wishes while placing the heat engine in injection cutoff in order to regenerate the particle filter. Furthermore, if the driver completely releases the accelerator pedal, it is also certain that the machine rotating electric is able to satisfy the driver's wishes while placing the engine in injection cut-off in order to regenerate the particle filter.

[0012] In addition to the characteristics which have just been mentioned in the previous paragraph, the process according to this aspect of the invention may present one or more complementary characteristics among the following, considered individually or in all technically possible combinations.

[0013] According to a non-limiting aspect of the invention,

The step of controlling an injection cut-off is carried out by gradually reducing an engine torque supplied by the thermal engine until the determined loss torque is reached, and

The step of providing the requested torque is carried out by compensating for the reduction in motor torque by a simultaneous progressive increase in machine torque supplied by the rotating electric machine.

[0014] According to a non-limiting aspect of the invention, the maximum torque that the rotating electric machine can provide is a function of a state of charge of a power battery arranged to electrically power the rotating electric machine and of characteristics of the rotating electric machine.

[0015] According to a non-limiting aspect of the invention, the maximum torque that the rotating electrical machine can provide is also a function of a state of wear of the rotating electrical machine.

[0016] According to a non-limiting aspect of the invention, the method comprises a step, executed by the control means, of stopping the step of controlling an injection cut-off of the heat engine if the particle content is less than one second threshold particle rate lower than the first threshold particle rate.

Another aspect of the invention relates to a hybrid vehicle comprising control means arranged to execute the steps of the method according to any of the aforementioned aspects of the invention.

[0018] According to a non-limiting aspect of the invention, the hybrid vehicle comprises a 48V or 400V type power battery.

The invention and its various applications will be better understood on reading the following description and examining the accompanying figures. [0020] [Fig. 1] illustrates, schematically, a hybrid vehicle according to a non-limiting aspect of the invention.

[0021] [Fig. 2] shows, schematically, the steps of a process according to a non-limiting aspect of the invention.

[0022] [Fig. 3] is a representative graph of torque curves.

Unless otherwise specified, the same element appearing in different figures presents a unique reference.

[0024] Figure 1 schematically illustrates a hybrid vehicle 1 conforming to a non-limiting implementation of the invention.

[0025] In a non-limiting manner, the hybrid vehicle 1 can be formed by a hybrid vehicle of the 48V or 400V type.

[0026] The hybrid vehicle 1 comprises:

A heat engine 2;

An exhaust line 3 of the combustion gases emitted by the heat engine 2

A particle filter 4 placed in the exhaust line 3 of the combustion gases emitted by the heat engine 2;

A clutch 5;

A rotating electric machine 6;

A 7 gearbox;

A front wheel shaft 8;

A 400V type power battery 9 arranged to electrically power the rotating electric machine 6;

Means of control 10.

[0027] In this non-limiting embodiment, when the clutch 5 is closed, the heat engine 2 is mechanically connected to the front wheel shaft 8 and is able to transmit a torque to the front wheel shaft 8 . [0028] Furthermore, when the rotating electric machine 6 is electrically powered by the power battery 9, the rotating electric machine 6 is able to transmit a torque to the front wheel shaft 8.

In other words, the heat engine 2 and the rotating electric machine 6 can be actuated simultaneously or independently of one another to transmit torque to the front wheel shaft 8.

The control means 10 are arranged to execute the steps of the process for regenerating a hybrid vehicle particle filter according to a non-limiting aspect of the invention illustrated in Figure 2.

[0031] In a non-limiting manner, the control means 10 can be formed by a vehicle control unit (better known by the acronym VCU for Vehicle Control Unit in English).

[0032] Figure 2 shows a step diagram of a mode of implementation of the method 100 according to the invention and Figure 3 shows torque curves as a function of time making it possible to illustrate the steps of the method 100.

[0033] More particularly, Figure 3 illustrates:

A maximum torque C1 that the rotating electric machine 6 can provide;

A motor torque C2 supplied by the heat engine 2;

A pair of losses C3 of the heat engine 2;

A minimum torque C4 that a driver of vehicle 1 can request;

A couple requested C5 by a driver of vehicle 1; And

A machine couple C6 supplied by the rotating electric machine 6.

The steps of the method 100 are executed by the control means 10 when the particle filter 4 has a particle content greater than a first threshold particle content and a temperature greater than a threshold temperature. To this end, sensors can transmit particle rate and temperature measurements to the control means 10 in order to compare them with the first threshold particle rate and the threshold temperature.

The method 100 includes a step of determining a maximum torque C1 that the rotating electric machine 6 can provide. [0036] In a non-limiting implementation, the maximum torque C1 that the rotating electric machine 6 can provide can be a function of a state of charge of the power battery 9 and of characteristics of the rotating electric machine 6.

The state of charge, also known by the acronym SoC (for State of Charge in English) can be provided by a battery control system (not illustrated) to the control means 10. The characteristics of the rotating electrical machine 6 can for example be recorded by the manufacturer in the control means 10. These characteristics can for example correspond to a maximum torque C1 that the rotating electrical machine 6 can provide at a given operating temperature.

[0038] The maximum torque C1 that the rotating electrical machine 6 can provide can also be a function of a state of wear of the rotating electrical machine 6. In a non-limiting manner, this state of wear can be determined by a number of hours of use of said rotating electric machine 6 or a total distance traveled by the vehicle 1.

[0039] The method 100 also includes a step, executed by the control means 10, of determining 102 a pair of losses C3 of the heat engine 2. This pair of losses C3 corresponds to the torque provided by the heat engine 2 when it is in injection cutoff. It can be recorded by the manufacturer in the control means 10.

The method 100 also includes a step, executed by the control means 10, of determining 103 a minimum torque C4 that a driver of the vehicle 1 can request. This minimum torque C4 corresponds for example to a set torque predetermined by the manufacturer and applied only in the event of release of the accelerator pedal of the vehicle 1. It can be recorded by the manufacturer in the control means 10 and can be used a slope of the road on which the vehicle is located and/or a vehicle load.

The method 100 also includes a step, executed by the control means 10, of determining a requested torque C5 by a driver of the vehicle 1. This torque request can be measured by an accelerator pedal movement sensor of the vehicle 1, then transmitted to the control means 10. This torque requested C5 by the driver is an instantaneous torque reflecting the driver's will at a given moment.

[0042] If the maximum torque C1 that the rotating electric machine 6 can provide is able to compensate, on the one hand, the loss torque C3 of the thermal engine 2 when it is in injection cut-off to which we add the minimum torque C4 that the driver is likely to request and, on the other hand, the loss torque C3 to which we add the torque requested C5 by the driver of the vehicle 1, the method 100 comprises the steps of:

Control 105 an injection cut-off of the thermal engine 2;

Provide 106 the requested torque C5 by means of the rotating electric machine 6.

[0043] The injection cut-off consists of a system which cuts off the supply of fuel to the injection pump of the thermal engine 2. This injection cut-off phase will allow the supply of oxygen into the particle filter 4 and therefore begin its regeneration.

[0044] In a non-limiting implementation illustrated in zone Z of FIG. 3, the step of controlling 105 an injection cut-off is executed by progressively reducing the engine torque C2 supplied by the thermal engine 2 until reaching the pair of losses C3 determined. The step of providing 106 the requested torque C5 is, for its part, executed by compensating the reduction in motor torque C2 by a simultaneous progressive increase in the machine torque C6 supplied by the rotating electric machine 6.

[0045] In summary, when the particle filter 4 has a particle content greater than a first threshold particle content, a temperature greater than a threshold temperature and the maximum torque C1 that the rotating electrical machine 6 can provide is capable of to compensate on the one hand, the pair of losses C3 to which the minimum torque C4 is added and, on the other hand, the pair of losses C3 to which the requested torque C5 is added, the control means 10:

Control 105 an injection cut-off of the thermal engine 2;

Provide 106 the requested torque C5 by means of the rotating electric machine 6. [0046] In the example illustrated, these steps of controlling 105 and supplying 106 begin on the right Za and end on the right Zb.

[0047] Indeed, at the level of the line Za, the maximum torque C1 that the rotating electrical machine 6 can provide is able to compensate for the addition of the loss torque C3 and the torque requested C5 by the driver of the vehicle 1. Thus, if there is an injection cut-off positioning the engine torque C2 on the loss torque C3 and the torque requested C5 by the driver does not change, we are certain that the capacity of the rotating electric machine 6 is sufficient to place the heat engine 2 in injection cutoff.

[0048] At the level of the line Za, the maximum torque C1 that the rotating electrical machine 6 can provide is also able to compensate for the addition of the loss torque C3 and the minimum torque C4 that the driver is likely to request. Thus, if there is an injection cut-off and the torque requested C5 by the driver decreases until it reaches the minimum torque C4, we are certain that the capacity of the rotating electric machine 6 is sufficient to place the thermal engine 2 in injection cutoff.

[0049] From the right Zb, as the torque requested C5 by the driver of vehicle 1 further decreases, the machine torque C6 is also reduced.

[0050] The method further comprises a step, executed by the control means 10, of stopping 107 the step 105 of controlling an injection cut-off of the heat engine 2 if the particle rate is lower than a second particle rate threshold lower than the first threshold particle rate.

[0051] To this end, sensors can transmit particle rate measurements to the control means 10 in order to compare them to the second threshold particle rate.

The different aspects of the invention mentioned above present numerous advantages. Among these, we can cite:

Satisfy the driver's torque demand; And

Effectively reduce the particle rate of a particle filter.

Claims

1. Method (100) for regenerating a particle filter (4) of a hybrid vehicle (1), said method (100) being characterized in that it comprises, when said particle filter (4) has a higher particle content at a first threshold particle rate and a temperature above a threshold temperature, the steps, executed by control means (10) of said vehicle (1), of:

- Determine (101) a maximum torque (C1) that a rotating electric machine (6) of said vehicle (1) can provide;

- Determine (102) a pair of losses (C3) of a heat engine (2) of said vehicle (1) when said heat engine (2) is in injection cut-off;

- Determine (103) a minimum torque (C4) that a driver of said vehicle (1) can request;

- Determine (104) a torque requested (C5) by a driver of said vehicle (1);

- If said maximum torque (C1) that said rotating electrical machine (6) can provide is able to compensate, on the one hand, said torque of losses (C3) added to said minimum torque (C4) and, on the other hand, said pair of losses (C3) added to said requested pair (C5);

- Control (105) an injection cut-off of said thermal engine (2); And

- Provide (106) said requested torque (C5) by means of said rotating electric machine (6).

2. Method (100) according to the preceding claim, characterized in that:

- The step of controlling (105) an injection cut-off is executed by progressively reducing an engine torque (C2) supplied by the heat engine (2) until reaching the determined loss torque (C3), and

- The step of providing (106) the requested torque (C5) is executed by compensating the reduction in said motor torque (C2) by an increase simultaneous progressive of a machine torque (C6) supplied by the rotating electric machine (6).

3. Method (100) according to any one of the preceding claims, characterized in that the maximum torque (C1) that the rotating electric machine (6) can provide is a function of a state of charge of a power battery ( 9) arranged to electrically power said rotating electric machine (6) and characteristics of said rotating electric machine (6).

4. Method (100) according to the preceding claim, characterized in that the maximum torque (C1) that the rotating electrical machine (6) can provide is also a function of a state of wear of said rotating electrical machine (6).

5. Method (100) according to any one of the preceding claims, characterized in that it comprises a step, executed by the control means (10), of stopping (107) the step of controlling (105) a cut-off injection of the heat engine (2) if the particle rate is lower than a second threshold particle rate lower than the first threshold particle rate.

6. Hybrid vehicle (1) characterized in that it comprises control means (10) arranged to carry out the steps of the method (100) according to any one of the preceding claims.

7. Hybrid vehicle (1) according to the preceding claim, characterized in that it comprises a power battery (9) of the 48V or 400V type.