Method for controlling a traction device for an automatic vehicle equipped with an electrically heated combustion gas treatment device.

Abstract

The internal combustion engine (1) comprises at least one intake valve (22), at least one exhaust valve (23) for combustion gases produced by the internal combustion engine (1), and a plurality of cylinders (2, 3, 4) each provided with a fuel injector (6, 7, 8), and an operating temperature (T S 2. A method for controlling a traction device for a motor vehicle comprising a treatment device (18) for combustion gases operating from an exhaust valve (23), the treatment device (18) being located downstream of the exhaust valve (23).

Description

Technical Field

[0001] The present invention relates generally to reducing the emissions of pollutants by an automotive vehicle internal combustion engine.

[0002] More particularly, the present invention relates to a method for controlling a traction device for an automotive vehicle for reducing the emissions of pollutants by a spark ignition or compression ignition internal combustion engine, and to a related traction device.

Background Art

[0003] A spark ignition engine is understood to mean any internal combustion engine in which combustion is initiated by a spark plug in the combustion chamber of the engine, for example a gasoline, alcohol, LPG or gas engine.

[0004] A compression ignition engine is understood to mean any internal combustion engine in which combustion is initiated by an increase in pressure in the combustion chamber of the engine, for example a diesel engine consuming diesel fuel.

[0005] Generally, at least one combustion gas treatment device, referred to as a catalyst or catalytic converter, is installed in the exhaust of the engine to treat combustion gases such as hydrocarbons, carbon monoxide or other nitrogen oxides emitted by the engine.

[0006] In the case of a spark ignition engine, for example, the device can be a three-way catalyst. In the case of a compression ignition engine, for example, the device can be an oxidation catalyst.

[0007] The efficiency of the catalyst is related to its temperature. When the catalyst is cold, i.e. at a temperature below its operating temperature, the catalyst does not operate or operates hardly at all. As a result, cold starts of the engine and operation during the first few seconds are accompanied by high emissions of pollutants.

[0008] The adjustments typically used in engines aim to reduce the efficiency of engine combustion. In controlled ignition engines, this generally involves adjusting the engine's ignition timing advance, thus offsetting the combustion toward gas expansion, a process traditionally referred to as under-advance. This results in an increase in exhaust gas temperature, and consequently, catalyst temperature, which reaches its operating temperature more quickly. In compression ignition engines, the same offset of combustion can generally be achieved by introducing a late phase in which fuel is injected into the engine cylinders.

[0009] However, despite the favorable rise in catalyst temperature, under-advancing or retarding injection operation simultaneously results in engine instability, excessive fuel consumption, and increased emissions of pollutants in particular. For example, in controlled ignition engines, the engine requires a larger airflow and, as a result, a larger fuel flow to maintain a corresponding richness, leading to an increase in exhaust flow and therefore an increase in the amount of pollutants emitted. In compression ignition engines, the airflow drawn into the engine is generally unchanged, but the fuel flow required to generate torque increases, combustion efficiency is compromised, and pollutant emissions are increased.

[0010] Another strategy to reduce the operation of engines with compromised combustion efficiency is to equip the vehicle's traction system with an electrically heated catalyst, in which heating occurs through convection between a heating grid and a monolith that forms the catalyst.

[0011] The quality of heat exchange between the grid and the catalyst is therefore crucial for the catalyst to reach its operating temperature quickly.

[0012] As described in U.S. Patent No. 5,357,752, one solution involves injecting an additional airflow upstream of the catalyst through an annular space located at the catalyst inlet.

[0013] However, this solution remains complex and expensive, as it requires the installation of additional components and modification of the catalyst to accommodate the air intake. Moreover, the solution is bulky and increases the mass of the traction device. [Overview of the Initiative]

[0014] Therefore, the present invention is directed toward proposing a method for controlling a traction device that overcomes these disadvantages and enables the catalyst to reach its operating temperature more rapidly without promoting catalyst heating and increasing the emission of pollutants.

[0015] Therefore, proposed is an internal combustion engine comprising a plurality of cylinders, each provided with at least one intake valve, at least one exhaust valve for combustion gases produced by the internal combustion engine, and a fuel injector, and a method for controlling a traction device for an automatic vehicle, comprising a device for processing combustion gases operating from an operating temperature, the device comprising a processing unit located downstream of the exhaust valve.

[0016] In addition, the traction device includes an electric heating means and control device for heating the combustion gas treatment device. The temperature of the combustion gas treatment device is compared to an operating threshold temperature, and as long as the temperature of the combustion gas treatment device is below the threshold temperature, the heating means of the combustion gas treatment device is activated, and the supply of fuel to one or more cylinders of the engine is cut off.

[0017] Advantageously, the control device can perform the following steps: determining the speed of the traction device and the depression of the accelerator pedal; calculating the torque setpoint of the traction device as a function of the determined speed of the traction device and the determined depression of the pedal; and controlling the deactivation of the fuel supply to one or more cylinders as a function of the calculated torque setpoint of the traction device.

[0018] More advantageously, the control method may include control by a control device of the opening rate of the intake and exhaust valves of the cylinder from which the fuel supply is cut off.

[0019] According to another advantageous feature, the control method may include the distribution by the control device of the torque of the traction device to be supplied between the traction device's electric motor and the control ignition engine when the temperature of the processing device is below the operating threshold temperature.

[0020] Preferably, when the temperature of the treatment device is below the operating threshold temperature, the control device cuts off the fuel supply to all cylinders of the controlled ignition engine, and the entire torque of the traction device is supplied by the electric motor.

[0021] Preferably, the control method includes the determination by a control device of the difference between the temperature of the processing device and the operating threshold temperature, and the distribution of torque for the traction device to be supplied by the electric motor and the internal combustion engine, respectively, as a function of the determined difference.

[0022] The present invention also relates to an internal combustion engine comprising a plurality of cylinders, each of which is provided with at least one intake valve, at least one exhaust valve for combustion gases produced by the engine, and a fuel injector, and to a traction device for an automatic vehicle comprising a treatment device for combustion gases that operates from an operating temperature, the treatment device being located downstream of the exhaust valve.

[0023] In addition, the traction device includes an electric heating means for heating the processing device, a temperature sensor configured to record the temperature of the processing device, and a control device configured to activate the heating means for the processing device and cut off the fuel supply to one or more cylinders of the engine as long as the temperature of the processing device is below an operating threshold temperature.

[0024] Preferably, the control device is configured to: determine the speed of the traction device and the depressure of the accelerator pedal; calculate the torque setpoint of the traction device as a function of the determined speed and the determined depressure; and control the cessation of fuel supply to one or more cylinders as a function of the calculated torque setpoint of the traction device.

[0025] Advantageously, the control device may be able to control the degree to which the intake and exhaust valves of the cylinders from which the fuel supply is cut off are opened.

[0026] More preferably, the traction device can include an electric motor, and the control device is configured to command at least a partial traction of the motor vehicle by the electric motor as long as the temperature of the processing device is below the operating threshold temperature.

[0027] Preferably, the control device is configured to cut off the supply of fuel into all cylinders of the internal combustion engine and to command the overall supply of torque of the traction device by the electric motor when the temperature of the processing device is below the operating threshold temperature.

[0028] Preferably, the control device is configured to determine the difference between the temperature of the processing device and the operating threshold temperature and to determine the distribution of the torque to be supplied respectively by the electric motor and the internal combustion engine as a function of the determined difference.

[0029] The invention further relates to a motor vehicle comprising a traction device as described above.

[0030] Other objects, advantages and features will become apparent from the following description, given by way of example only and with reference to the accompanying drawings.

Brief Description of the Drawings

[0031] [Figure 1] It is a diagram schematically illustrating a traction device including an engine connected to a processing device for combustion gases generated by the engine, which is a controlled ignition type internal combustion engine according to an embodiment of the present invention. [Figure 2] It is a cross-sectional view of a cylinder of a controlled ignition engine as illustrated in FIG. 1. [Figure 3] It is a diagram illustrating a method for controlling a traction device for a motor vehicle including an electrically heated combustion gas processing device.

Embodiments of the Invention

[0032] As illustrated in Figure 1, the internal combustion engine 1 of the traction device comprises multiple cylinders 2, 3, and 4. In the illustrated example, the engine 1 is provided with three cylinders 2, 3, and 4. In the example illustrated by Figure 1, the engine is of the controlled ignition type, but it may also be a compression ignition engine without departing from the scope of the present invention.

[0033] Each cylinder 2, 3, and 4 is equipped with its respective fuel injectors 6, 7, and 8, which can be supplied with fuel via a duct 5, such as a common fuel rail 5.

[0034] Air 10 is supplied to the supply duct 9 and, advantageously, proceeds to each cylinder 2, 3, and 4 via the respective intake ducts 11, 12, and 13.

[0035] In this representation, exhaust ducts 14, 15, and 16 for the combustion gases produced by engine 1 extend from cylinders 2, 3, and 4, respectively. The three exhaust ducts 14, 15, and 16 extend toward a common duct 17 which is connected to a treatment device 18 for the combustion gases produced by engine 1.

[0036] In addition, the treatment apparatus 18 operates from an operating temperature and corresponds to, for example, a three-way catalyst for the simultaneous treatment of nitrogen oxides, carbon monoxide, and hydrocarbons. Other types of treatment apparatus 18 can be considered as variations, for example, the apparatus may be a nitrogen oxide trap, not limited thereto. For example, if the engine is of the compression ignition type, the apparatus may be an oxidation catalyst. In addition, the treatment apparatus 18 includes means 21 for determining the temperature of the apparatus 18, for example, a temperature sensor 21. In a very common variation, which may also be included here, is a model that is a function of a set of engine operating parameters, including at least engine speed, engine torque, and engine coolant temperature, which makes it possible to obtain, for example, the temperature of the catalyst 18.

[0037] In the illustrated example, the processing unit 18 is located upstream of an exhaust silencer 19, which is intended to exhaust the gas 20 processed by the processing unit 18.

[0038] Figure 2 illustrates a cross-sectional view of one of the cylinders 2, 3, and 4 of engine 1. In the illustrated example, the three cylinders 2, 3, and 4 are similarly configured. Cylinder 2, as depicted, comprises a combustion chamber 24, a piston 25, and a spark plug 26.

[0039] In addition, cylinder 2 is equipped with an intake valve 22 and an exhaust valve 23 for the combustion gases produced by engine 1. Of course, it is conceivable that each cylinder 2, 3, and 4 may be provided with an additional intake valve 22 and an additional exhaust valve 23. Valves 22 and 23 are shown in the open position.

[0040] As illustrated in Figures 1 and 2, fuel injectors 6, 7, and 8 are connected to the control unit 27.

[0041] Preferably, the intake valve 22, exhaust valve 23, and temperature sensor 21 are also connected to the control device 27 in the same way.

[0042] Furthermore, the traction device includes an electric heating means 28 for heating the processing apparatus 18. In the illustrated example, the processing apparatus 18 includes a heating grid 28 positioned to face the monolith 29 of the processing apparatus 18.

[0043] The temperature T of the combustion gas treatment device is the operating threshold temperature T. S It is compared to this.

[0044] The catalyst temperature is generally below its operating threshold temperature when engine 1 is cold, especially during startup and the first few seconds of engine operation.

[0045] The temperature T of the combustion gas treatment device 18 is, in step 30, its operating threshold temperature T S When the value is less than the specified value, the heating means of the processing unit is activated, and the fuel supply to one or more cylinders 2, 3, and 4 is cut off.

[0046] On the other hand, the operation of the intake valve 22 and exhaust valve 23 is kept constant, and the valves open and close according to the normal operation of the engine.

[0047] In the illustrated example, the heating means 28 is activated by a control device 27, which cuts off the injection of fuel into one of the cylinders, i.e., cylinder 2.

[0048] Preferably, in the illustrated example, with respect to a controlled ignition engine, the ignition of the spark plug in the cylinder where fuel injection is cut off is also cut off. Only the opening and closing of the intake valve 22 and exhaust valve 23 continues to operate normally.

[0049] In this configuration, when the intake valve 22 and exhaust valve 23 open in accordance with the normal operation of the engine, the air 10 injected into the intake duct 11 passes through the cylinder 2 toward the exhaust duct 14. The air can then be directed toward the treatment device 18.

[0050] When the treatment device 18 reaches its operating threshold temperature and begins to efficiently treat the pollutant emissions from engine 1, the fuel supply to all cylinders 2, 3, and 4 is re-established.

[0051] Of course, it is possible to cut off the fuel supply to multiple cylinders 2, 3, and 4.

[0052] The opening of the intake valve 22 and exhaust valve 23 of the cylinders not supplied with fuel thus allows air to pass toward the treatment apparatus 18. This increased airflow and its contact with the heating means 18 has the consequence of promoting heat exchange between the heating means 28, in this case the heating grid and the catalyst monolith 18, leading to a more rapid rise in the temperature of the treatment apparatus 18. The treatment apparatus 18, and in particular the monolith, has an operating threshold temperature T S This leads to a rapid reduction in hydrocarbon production, resulting in a decrease in pollutant gas emissions.

[0053] The increase in airflow within the processing device 18 is therefore generated without any modification of the traction device or the incorporation of any additional elements. In addition, the control method according to the present invention is applicable to both direct injection engines and indirect injection engines.

[0054] Furthermore, the control device 27 may have a mechanism to control the degree to which the intake valves 22 and exhaust valves 23 of cylinders 2, 3, and 4 are opened, thereby cutting off the fuel supply. In this way, the valves 22 and 23 may be opened completely or partially.

[0055] Furthermore, the control device 27 can be configured to control the cessation of fuel supply to one or more cylinders as a function of the torque setting value of the traction device.

[0056] For this purpose, the control device 27 calculates a torque set value for the traction device as a function of the traction device speed and the depression of the accelerator pedal, which are determined in advance.

[0057] In the case of a hybrid automatic vehicle, the control device 27 may also be configured to control the distribution of torque to be supplied between the electric motor and the internal combustion engine when the temperature of the processing device is below the operating threshold temperature.

[0058] For example, when the temperature of the processing unit is below the operating threshold temperature, the control unit 27 cuts off the fuel supply to all cylinders 2, 3, and 4 of the internal combustion engine 1, and the entire torque of the traction device is supplied by the electric motor.

[0059] Unless the treatment device 18 is not operating and is unable to treat the pollutants emitted by the operating internal combustion engine, the electric motor operates independently, and the torque of the traction device is ensured without the emission of pollutants.

[0060] In addition, the control device 27 controls the temperature T of the processing device and the operating threshold temperature T. S There may be measures to determine the difference between the two and the electric motor, and to distribute the torque of the traction device to be supplied by the electric motor and the internal combustion engine, respectively, as a function of the determined temperature difference.

[0061] For example, the temperature T of the processing unit 18 is its operating threshold temperature T. SAs the temperature approaches the target temperature, that is, as the determined temperature difference decreases, the control device 27 allocates more torque to the internal combustion engine 1, which is supplied by the traction device, and gradually re-establishes fuel injection into the multiple cylinders 2, 3, and 4. The internal combustion engine 1 then gradually starts up, with the emission of pollutants thus minimized.

[0062] Measures may also be taken to implement the above-described control method in engines other than those of automatic vehicles.

Claims

1. A method for controlling a powertrain for an automated vehicle, wherein the automated vehicle is an internal combustion engine (1), which comprises a plurality of cylinders (2, 3, 4) each provided with at least one intake valve (22), at least one exhaust valve (23) for combustion gases produced by the internal combustion engine (1), and fuel injectors (6, 7, 8), and an operating temperature (T Ｓ A combustion gas treatment device (18) that operates from the exhaust valve (23), comprising a combustion gas treatment device (18) located downstream of the exhaust valve (23), wherein the powertrain comprises an electric heating means (28) and a control device (27) for heating the combustion gas treatment device (18), and the temperature (T) of the combustion gas treatment device (18) is set to an operating threshold temperature (T). Ｓ ) is compared with (30), and the temperature (T) of the combustion gas treatment device (18) is compared with the threshold temperature (T Ｓ As long as it is less than ), the heating means (28) for the combustion gas treatment device (18) is activated (31), the fuel supply to one or more cylinders (2, 3, 4) of the internal combustion engine (1) is cut off, and the intake valve (22) and exhaust valve (23) of one or more cylinders (2, 3, 4) are opened and closed. The method includes the distribution by the control device (27) of the torque of the powertrain to be supplied between the electric motor of the powertrain and the internal combustion engine (1) when the temperature (T) of the combustion gas treatment device (18) is less than the operating threshold temperature (TS), A method characterized in that, when the temperature (T) of the combustion gas treatment device (18) is below the operating threshold temperature (TS), the control device (27) cuts off the fuel supply to all of the cylinders (2, 3, 4) of the internal combustion engine (1), and the entire torque of the powertrain is supplied by the electric motor.

2. The control device (27) performs the following steps: Determination of the speed of the powertrain and the depression of the accelerator pedal, Calculation of the torque set value of the powertrain as a function of the determined speed of the powertrain and the determined pedal depression, Control of stopping the fuel supply to one or more (2) cylinders of the powertrain as a function of the calculated torque setting value, and The method according to claim 1, characterized by carrying out the following.

3. The method according to claim 1 or 2, characterized in that the control device (27) controls the opening rate of the intake valve (22) and the exhaust valve (23) of the cylinder (2) whose fuel supply is cut off.

4. The temperature (T) and the operating threshold temperature (T) of the combustion gas treatment apparatus (18) Ｓ The method according to claim 1, characterized in that the control device (27) determines the difference between and ), and the distribution of the torque of the powertrain to be supplied by the electric motor and the internal combustion engine (1), respectively, as a function of the determined difference.

5. A powertrain for an automatic vehicle, wherein the automatic vehicle comprises an internal combustion engine (1), which has a plurality of cylinders (2, 3, 4) each provided with at least one intake valve (22), at least one exhaust valve (23) for combustion gases produced by the internal combustion engine (1), and fuel injectors (5, 6, 7), and an operating temperature (T Ｓ A processing device (18) for the combustion gases that operates from the exhaust valve (23), the processing device (18) being located downstream of the exhaust valve (23), the powertrain comprising an electric heating means (28) for heating the processing device (18), a temperature sensor (21) configured to record the temperature of the processing device (18), and the temperature (T) of the processing device being set to an operating threshold temperature (T Ｓ A control device (27) is provided which is configured to activate the heating means (28) of the processing device (18) as long as the value is less than ), cut off the supply of fuel to one or more cylinders (2, 3, 4) of the internal combustion engine, and open and close the intake valve (22) and exhaust valve (23) of one or more cylinders (2, 3, 4), The powertrain comprises an electric motor, and the control device (27) is configured to command the traction of the automatic vehicle by the electric motor, at least partially, as long as the temperature (T) of the processing device (18) is below the operating threshold temperature (TS). A powertrain characterized in that the control device (27) is configured to cut off the fuel supply to all cylinders (2, 3, 4) of the internal combustion engine (1) and to command the electric motor to supply the entire torque of the powertrain when the temperature (T) of the processing device (18) is below the operating threshold temperature (TS).

6. The aforementioned control device: The speed of the powertrain and the depression of the accelerator pedal are determined. The torque setting value of the powertrain is calculated as a function of the determined speed and the determined pedal depression. Controls the cessation of fuel supply to one or more cylinders (2) as a function of the calculated torque setting value of the powertrain. The powertrain according to claim 5, characterized in that it is configured as follows.

7. The powertrain according to claim 5 or 6, characterized in that the control device (27) can control the opening rate of the intake valve (22) and the exhaust valve (23) of the cylinder (2) from which the fuel supply is cut off.

8. The control device (27) controls the temperature (T) of the processing device (18) and the operating threshold temperature (T) Ｓ The powertrain according to claim 5, characterized in that it is configured to determine the difference between and , and to determine the distribution of the torque to be supplied by the electric motor and the internal combustion engine (1), respectively, as a function of the determined difference.

9. An automatic vehicle comprising the powertrain according to any one of claims 5 to 8.

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