FR3090740A1 - METHOD AND DEVICE FOR HEATING AT LEAST ONE PART OF AN AFTER-TREATMENT SYSTEM (ATS) OF AN INTERNAL COMBUSTION ENGINE - Google Patents

Abstract

The present invention relates to an assembly comprising an internal combustion engine (E) having an exhaust pipe (OP), an aftertreatment system (ATS) arranged on said exhaust pipe (OP) of a combustion engine internal (E) for treating the pollutants contained in an exhaust gas produced by the latter, the assembly further comprising means for heating at least part (ATS2) of said after-treatment system (ATS), in which said means comprise an electric turbine (EMT) arranged on said exhaust pipe (OP) and an electric heating device (HT) arranged on said exhaust pipe (OP) upstream of said at least one part (ATS2), wherein the electric heating device (HT) is supplied with electric energy generated by said electric turbine so as to increase a temperature of said at least one part (ATS2). Figure for the abstract: Figure 1

Description

Description

Title of the invention: Method and device for heating at least part of an aftertreatment system (ATS) of an internal combustion engine

Field of the invention

The present invention relates to a method and device for heating an ATS (aftertreatment system) of an internal combustion engine, in particular in the field of industrial vehicles.

Description of the prior art

The thermal management of T ATS is one of the major challenges to be met in order to meet future emission limits. Rapid warming and energy efficient temperature control are important.

In the field of diesel engines, the most temperature-sensitive ATS component is SCR (selective catalytic reduction). The SCR must operate above the so-called ignition temperature of 250 ° C. Indeed, at too low temperatures, the hydrolysis of the urea-based agent leads to the formation of crystals.

Similar considerations can be proposed for petrol engines fitted with a three-way catalyst (3WC).

The current thermal management approach, especially in the case of the diesel engine, is either to control the air flow, or to exacerbate fuel consumption to adjust the temperature and energy of the exhaust gas. . Generally, the air flow is controlled by a throttle at the inlet and / or outlet, a variation of valve timing and an uncooled EGR (exhaust gas recirculation), while conventional strategies to exacerbate fuel consumption in order to increase the energy and the temperature of the exhaust gas offer late injection timing or post-injection, even in combination with an exhaust throttle.

[0006] In gasoline engines, the implementation of enrichment strategies is usually based on the exacerbation of fuel consumption.

Another known method for managing the temperature of ATS is the installation of an electric heating device. However, the electrical energy drained by said electric heating device is high and, on cold starting, vehicle batteries may suffer from the activation of the electric heating device.

This is the main reason why the electric heating elements, even well known, have not been widely implemented, the flow control or the exacerbation of the fuel consumption described above being preferred. .

Summary of the invention

The main object of the present invention is to provide thermal management of the ATS after-treatment system of an internal combustion engine based on an electric heating device.

The essential principle of the invention is the implementation of an electric turbine coupled to an electric heating device arranged on the exhaust pipe, upstream of a device for reducing pollutants sensitive to temperature, such as a SCR or a 3WC.

According to a preferred embodiment of the invention, the heating device is exclusively connected to the generator driven by the turbine, so that the electrical energy generated is fully reused by the heating device. Preferably, no rechargeable battery is adopted.

Therefore, the thermal management system according to the present invention is electrically isolated, at least during the warming of ATS.

Thus, it can define an independent kit, equipped with its own temperature sensor and a control unit programmed to control the amount of mechanical energy which must be extracted by the exhaust gas produced by the engine to internal combustion. The kit can thus include the above electric turbine and an electric heating device directly associated with a part of the body of the turbine, forming a single component. In this case, the electric turbine can be controlled by actuating its variable geometry, or by acting on a relief valve arranged on a bypass path of the turbine itself. In addition, the bypass path can be made in the body of the electric turbine, so as to obtain a single autonomous device.

Alternatively, the heating system may include several components, some of which are already present in a vehicle, such as the engine control unit and the various sensors usually arranged with the ATS. The internal combustion engine can be fitted with a turbocharger unit, the turbine of which is arranged on the exhaust pipe, upstream of the electric turbine, and the mechanical energy extracted by the electric turbine can be adjusted by in addition to the mechanical energy extracted for the stimulation of the engine by the turbocharger.

In order to manage the amount of mechanical energy which must be extracted by the exhaust gas, the turbine can be of variable geometry so as to vary the section of outgoing flow, or can have a bypass with a valve. discharge arranged so as to ensure throttling in a manner proportional to the mechanical energy to be extracted by the electric turbine. In other words, the greater the throttle in the relief valve, the more the gas flow passes through the turbine and the more mechanical energy can be extracted.

By using an electrified turbine in combination with an electrically heated ATS, as an exhaust valve, the back pressure increases and the working point of the engine shifts towards a higher fuel consumption, differently from a valve d 'exhaust, the back pressure is not dissipated but used to generate energy reused at the same time in the warming of ATS.

According to a preferred embodiment of the invention, after heating, the turbine is bypassed. While, according to another preferred embodiment of the invention, the electric turbine is at least partially traversed by the exhaust gas produced by the internal combustion engine, and the electric generator is electrically disconnected by the heating device and connected to the vehicle electric bus to contribute to the generation of electrical energy.

According to another preferred embodiment of the invention which can be combined with any one of the preceding embodiments, the electric turbine is a part of what is called a “turbocharger of electric supercharging”, namely an assembly comprising a compressor arranged on the intake pipe of the internal combustion engine, a turbine arranged on the exhaust pipe of the same internal combustion engine, the turbine and the compressor sharing a common shaft, which in turn , defines the rotor of the above electric generator, or is mechanically connected to it.

In this case also, during heating, the electrical energy extracted depends on the available residual mechanical energy net of the stimulation energy necessary for the compression of fresh air at the inlet of the combustion engine. internal.

Advantageously, at low load, the VGT (variable geometry turbocharger) can be closed, therefore, the exhaust enthalpy collected increases, while the increase in mass air flow at entry can be avoided by braking the turbocharger by means of its own electric generator.

In this case also, after the heating, the electric generator is electrically disconnected from the electric heating device and connected to an electric vehicle bus.

Advantageously, turbomachines comprising the turbocharger are currently used to supercharge internal combustion engines, such components are therefore readily available on the market.

The proposed invention combines known technologies to obtain an effective temperature control of ATS based on the recovery by enthalpy of waste.

A first object of the present invention is a method of heating at least part of an aftertreatment system arranged on an exhaust pipe of an internal combustion engine to treat the pollutants contained in a exhaust gas produced by it, the method comprising the preliminary step of arranging an electric turbine on said exhaust pipe and an electric heating device on said exhaust pipe upstream of said at least one part, the method comprising the procedure of supplying the electric heating device with electric energy generated by said electric turbine so as to increase a temperature of said at least part.

A second object of the present invention is an assembly comprising an internal combustion engine having an exhaust pipe, a post-treatment system arranged on said exhaust pipe of the internal combustion engine for treating the pollutants contained in an exhaust gas produced by the latter, the assembly further comprising means for heating at least part of said after-treatment system, wherein said means comprise an electric turbine arranged on said exhaust pipe and a device electric heating device arranged on said exhaust pipe upstream of said at least one part, in which the electric heating device is supplied with electric energy generated by said electric turbine so as to increase a temperature of said at least one part.

Another object of the present invention is an internal combustion engine comprising said device.

The present invention can be applied to both a diesel engine and a gasoline engine.

These and other objects are achieved by means of the appended dependent claims, which describe preferred embodiments of the invention, which are an integral part of the present description.

Brief description of the drawings

The invention will appear clearly in the following detailed description, given by way of example and not limiting, to be read with reference to the attached drawings, in which:

[Fig-1] Figure 1 shows a diagram of a first embodiment of the invention;

[Fig.2] Figure 2 shows a slight variation of the embodiment of Figure 1; [Fig.3] Figure 3 shows a variation of the embodiment of Figure 1 or 2 of the invention;

[Fig-4] Figure 4 shows another variation of the embodiment of the invention, based on the diagram of Figure 1, according to a first operating condition;

[Fig.5] Figure 5 shows the embodiment of Figure 4 according to a second operating condition;

[Fig.6] Figure 6 discloses an additional embodiment of the invention exploiting the second operating condition disclosed in Figure 5.

The same numbers and reference letters in the figures denote identical or functionally equivalent parts.

According to the present invention, the expression "second element" does not imply the presence of a "first element", first, second, etc. are only used to improve the clarity of the description and should not be interpreted in a limiting manner.

Detailed description of the preferred embodiments

Examples of embodiments are now provided so that this disclosure is complete for those skilled in the art.

Figures 1 to 6 disclose an internal combustion engine E, preferably a diesel engine.

The engine E has an intake pipe IP and a discharge pipe OP, so that the engine draws fresh air from the environment through the intake pipe and rejects an exhaust gas into the environment via the OP (or exhaust) discharge pipe.

Along the discharge line, one or more reduction devices are arranged, and, only by way of example, they are grouped into two parts ATS1 and ATS2 of the ATS after-treatment system.

For example, for a diesel engine, the ATS1 part can include a DOC (diesel oxidation catalyst) and a DPL (diesel particle filter), while the ATS2 part can include a SCR (selective catalytic reduction) and a dosing module arranged immediately upstream of the SCR to introduce a urea-based reducing agent, usually called by its trade name, AdBlue.

Downstream from the ATS2 part, other components can be designed, such as a CUC (purification catalyst) and an ME silencer.

According to the present invention, an electric turbine EMT, comprising an electric generator EM and a turbine T operatively driving the electric generator EM, is arranged on the discharge pipe so as to produce electric energy from '' an enthalpy content of the exhaust gas.

The turbine is of variable geometry, or is of fixed geometry coupled to a branch pipe BP suitable for bypassing the turbine T, and, on said branch is arranged a relief valve WG which can be controlled in order to adjust the quantity of exhaust gas passing through the turbine T.

An HT electric heating device is arranged inside the discharge pipe, the heating device is for example arranged upstream of T ATS whole or only upstream of the device most sensitive to the temperature of T ATS .

According to Figure 1, the EMT electric turbine is arranged upstream of the ATS, while the HT electric heating device is arranged between the parts ATS1 and ATS2 of the ATS.

According to the present invention, the back pressure generated by the turbine T is converted into electrical energy used to heat the exhaust gas. As a result, not only does the engine work point change, but the energy content of the exhaust gas is trapped inside the ATS by the electric turbine and the electric heater.

Preferably, a direct electrical connection interconnects the electric generator EM by producing an electrically isolated assembly.

According to a preferred embodiment of the invention, the electric turbine and the heating device are made of a single component. The turbine itself defines part of the discharge line, therefore the heater can be arranged just downstream of the turbine scroll.

The electric turbine can also include a CU control unit, and a temperature sensor (not disclosed) in order to regulate the mechanical energy extracted by the T turbine based on the temperature of the exhaust gas.

It should be understood that the control unit can be provided with a CAN bus port in order to be connected to the vehicle data network and to acquire the exhaust gas temperature and the engine speed deployed on the data network.

According to a preferred embodiment of the invention, during the heating of ATS, the control unit CU can control the turbine, and thus the back pressure to be supplied to the internal combustion engine on the basis of other parameters as well, such as engine speed.

According to Figure 3, the engine has a turbocharger TCU "normal", like a turbine Tl driving a compressor Cl, in which the turbine is arranged on the discharge line upstream of the ATS and the compressor Cl is arranged on the intake pipe of the engine in order to supercharge the internal combustion engine.

Now, the CU control unit, which controls the electric turbine, can be programmed to produce a back pressure, which takes into account the back pressure produced by the turbocharger TCU.

In other words, the electric turbine completes the backpressure of the turbocharger boost pressor in order to maintain this backpressure over a predetermined range, as long as the reheating procedure is in progress.

The stimulation parameter can also be extracted by the vehicle data network, as described above.

According to another embodiment of the invention, the control unit is fully integrated in the ECU control unit (engine control unit) arranged to control at least the internal combustion engine. In this case, the control unit is already connected to the vehicle data network, it thus manages the stimulation level, the injection of fuel into the cylinders of the internal combustion engine, and can thus easily adjust the back pressure. of electric turbine.

In this case also, preferably, the electric generator EM and the electric heating device HT define an isolated circuit with respect to the electric bus of the vehicle. By “vehicle electric bus” is meant an electrical power network which has nothing to do with the data network in which the command and status messages are deployed.

Liguria 4 and 5 disclose another embodiment of the invention in which an E-TCU electric supercharging turbocharger is used.

The above electric turbine is part of the E-TCU.

The E-TCU is an assembly comprising a compressor C arranged on the intake pipe of the internal combustion engine, the turbine T arranged on the exhaust pipe of the same internal combustion engine, the turbine and the compressor. sharing a common shaft SH, which in turn defines the rotor of the above electric generator EM, or is mechanically connected to it.

Here, the negative torque of the generator, as above, is controlled at least during warming up, in order to supplement the mechanical energy necessary for the compressor C to reach a predetermined stimulation of the internal combustion engine. In this way, a predetermined back pressure value is reached and maintained.

In other words, this strategy, as above, makes it possible not to exceed a predetermined backpressure value.

Even if it is preferable, during warming, not to implement battery storage to power the electric heating device, after warming, the electric generator can be used to charge a battery, like a block - lithium battery or a supercapacitor, connected to the vehicle electrical network.

Many specific details are cited as examples of specific components, devices and methods in order to allow an in-depth understanding of the embodiments of the present disclosure. It will be obvious to those skilled in the art that specific details need not be used, that the exemplary embodiments can be in many different forms and that none of these examples should be interpreted as limiting the scope of the disclosure. In some exemplary embodiments, well-known processes, well-known device structures are disclosed.

This invention can be implemented advantageously in a computer program comprising program code means for performing one or more steps of this method, when this program is executed on a computer. For this reason, the patent must also cover such a computer program and the computer-readable medium which comprises a recorded message, such a computer-readable medium comprising the program code means for carrying out one or more steps of such a method, when this program is run on a computer.

Many changes, modifications, variations and other uses and applications of the present invention will become apparent to those of skill in the art after examining the specification and accompanying drawings which disclose preferred embodiments of the invention as described in the appended claims.

The features disclosed in the context of the prior art are only introduced in order to better understand the invention and not as a declaration on the existence of a known prior art. Furthermore, said characteristics define the context of the present invention, these characteristics must therefore be considered together with the detailed description.

Other details of implementation will not be described, because the person skilled in the art is capable of accomplishing the invention from the teaching of the description above.

Claims (1)

Claims [Claim 1] Method for heating at least part (ATS2) of an aftertreatment system (ATS) arranged on an exhaust pipe (OP) of an internal combustion engine (E) to treat the pollutants contained in a exhaust gas produced therefrom, the method comprising the preliminary step of arranging an electric turbine (EMT) on said exhaust pipe (OP) and an electric heater (HT) on said exhaust pipe (OP) upstream of said at least one part (ATS2), the method comprising the procedure consisting in supplying the electric heating device (HT) with electric energy generated by said electric turbine (EMT) so as to increase a temperature of said at least part (ATS2). [Claim 2] The method of claim 1, wherein said electric turbine (EMT) comprises a turbine (T) and an electric generator (EM) and wherein the electric heating device is exclusively connected to the generator driven by said electric generator, without any means of electrical storage. [Claim 3] Kit for heating at least part (ATS2) of an aftertreatment system (ATS) arranged on an exhaust pipe (OP) of an internal combustion engine (E) for treating the pollutants contained in a gas d exhaust produced by it, the kit comprising an electric turbine (EMT) suitable for being arranged on said exhaust pipe (OP) and comprising a turbine body, and in which an electric heating device (HT) is arranged in a part of the turbine body, and in which the electric turbine (EMT) is arranged to supply the electric heating device (HT) so as to increase, during use, a temperature of said at least one part (ATS2 ). [Claim 4] The kit of claim 3, further comprising a control unit (CU) operatively connected to a temperature sensor operatively arranged opposite the turbine body for measuring an exhaust gas flowing therein. ci, wherein the control unit is configured to regulate an operation of said electric turbine according to a temperature measured by said temperature sensor. [Claim 5] Kit according to claim 4, - in which said turbine is provided with a variable geometry and said operating adjustment acts on said variable geometry, or wherein said turbine has a fixed geometry and comprises a bypass path on which a relief valve (WG) is arranged and in which said operating setting acts on said relief valve (WG). [Claim 6] Assembly comprising an internal combustion engine (E) having an exhaust pipe (OP), an aftertreatment system (ATS) arranged on said exhaust pipe (OP) of the internal combustion engine (E) for treating pollutants contained in an exhaust gas produced by the latter, the assembly further comprising means for heating at least part (ATS2) of said after-treatment system (ATS), in which said means comprise an electric turbine ( EMT) arranged on said exhaust pipe (OP) and an electric heating device (HT) arranged on said exhaust pipe (OP) upstream of said at least one part (ATS2), in which the electric heating device (HT) is supplied with electrical energy generated by said electric turbine so as to increase a temperature of said at least one part (ATS2). [Claim 7] Assembly according to claim 6, in which said electric turbine is arranged upstream or downstream of said at least part of the after-treatment system (ATS). [Claim 8] An assembly according to claim 6 or 7, wherein said electric turbine (EMT) is included in an electric supercharging turbocharger (E-TCU), comprising a compressor (C) arranged on an intake pipe (IP) of the combustion engine internal (E); said electric turbine (EMT) comprising an electric generator (EM) and a turbine (T), which is arranged on the exhaust pipe (OP) of the same internal combustion engine; the turbine (T) and the compressor (C) sharing a common shaft (SH), which defines a rotor of the electric generator (EM), or which is mechanically connected thereto; wherein, during heating, said electric generator is controlled to supplement mechanical energy drained by the compressor (C) to stimulate the internal combustion engine, so as to reach a predetermined backpressure value. [Claim 9] An assembly according to claim 6 or 7, further comprising a turbocharger (TCU) comprising a compressor (Cl) arranged on an intake pipe (IP) of the combustion engine internal, an additional turbine (Tl), arranged on the exhaust pipe (OP) of the same internal combustion engine; the additional turbine (Tl) and the compressor (Cl) sharing a common shaft (SH); wherein said electric turbine (EMT) comprises an electric generator (EM) and a turbine (T) driving the electric generator (EM); during reheating, said electric turbine is controlled to complete a back pressure generated by the second turbine (T2) of said turbocharger (TCU) to stimulate the internal combustion engine. [Claim 10] Assembly according to any one of the preceding claims 6 to 9, in which, after heating, an electric generator (EM) of said electric turbine (EMT) is electrically disconnected from the electric heating device and connected to a bus electric vehicle. [Claim 11] The assembly of claim 10, further comprising an electric motor (EMU) connected directly or indirectly to an internal combustion engine crankshaft (CK), wherein said electric motor (EMU) is arranged to be added to said internal combustion engine (CK) crankshaft, and wherein said vehicle electric bus comprises power storage means (BAT) suitable for powering said electric engine (EMU).