DE10355621A1 - Control unit, for I.C. engine, has electrical motor control unit which is controlled, such that air is prevented from being drawn into engine when exhaust gas-air-fuel ratio is rich - Google Patents

Abstract

Engine control unit comprises a NOx storage material in an exhaust gas line, a turbocharger connected to the engine, an electrical motor control unit for driving an electrical motor and controlling regeneration of the electrical performance. The air is prevented from being drawn into the engine when the exhaust gas-air-fuel ratio is rich, and NOx is released from the NOx storage material. Engine control unit comprises a NOx storage material (29) (reduction catalyst) in an exhaust gas line (6) of an I.C. engine, for storing NOx when the exhaust gas-air-fuel ratio of the incoming gas is lean, and for releasing NOx when the exhaust gas-air-fuel ratio of the incoming gas is rich or stoichiometric, a turbocharger (11) connected to the engine, an electrical motor (11b) for changing the charge pressure through a drive of a turbine-compressor unit (11a) of the turbocharger and for regenerating electrical performance using the exhaust gas energy, and an electrical motor control unit (16, 21) for driving the motor and controlling the regeneration of the electrical performance. The electrical motor control unit is controlled, such that air is prevented from being drawn into the engine when the exhaust gas-air-fuel ratio is rich, and NOx is released from the NOx storage material. An Independent claim is also included for a control process for an I.C. engine using the above control unit.

Description

TECHNOLOGICAL BACKGROUND 1 , Technical field

The invention relates to a Control device and a control method for an internal combustion engine with a NOx storage material in the exhaust pipe and a turbocharger with an electric motor set up in the turbine-compressor unit.

Since the demands lately for improvements in fuel economy and clean Exhaust gases have increased, lean-burn engines and the like for the practical Use developed. Usually comes with a lean-burn engine either a combination of a NOx storage material and one Three-way catalytic converter or an exhaust gas purification catalytic converter of the NOx storage reduction type used to during to reduce the lean NOx released. In this way the rate of reduction of the NOx contained in the exhaust gas is increased. The NOx storage material has the function of lean air-fuel ratio incoming Exhaust gas NOx (nitrogen oxide) and store at a rich or stoichiometric Air-fuel ratio release the stored NOx. Accordingly stores the NOx storage material temporarily NOx, which releases at a lean air-fuel ratio of the exhaust gas and releases the stored NOx at a rich or stoichiometric Air-fuel ratio of the exhaust gas, which is then released using the three-way catalytic converter is degraded (in the case where the exhaust gas purification catalyst a NOx storage reduction catalyst the exhaust gas purification catalytic converter removes the NOx itself). Around Forced mining of the stored NOx can be a so-called (in specialist circles also known as a "rich spike") by the air-fuel ratio of the exhaust gas is briefly greased.

An internal combustion engine in which an enrichment tip action is carried out is known, for example, from Japanese Patent Application Laid-Open No. JP 2001-55946 A known. In this internal combustion engine, the boost pressure is increased by means of a turbocharger in order to achieve better atomization of the fuel injected in large quantities during the enrichment spike action. When the enrichment peak action is carried out in an internal combustion engine with a turbocharger, however, the exhaust gas energy and the boost pressure also increase. Accordingly, it is difficult to obtain a rich air-fuel ratio of the exhaust gas. In addition, the JP 2001-55946 A known internal combustion engine to obtain better atomization of the fuel increases the boost pressure even more (which means that the amount of intake air continues to increase). Accordingly, it is questionable whether the air-fuel ratio of the exhaust gas can be enriched sufficiently and the effect of the enrichment peak action can be achieved sufficiently.

SUMMARY THE INVENTION

According to the invention is on an internal combustion engine a turbocharger with one set up in a turbine compressor unit Electric motor provided. Accordingly, it is possible to go through a drive of the electric motor for driving the turbine-compressor unit the turbocharger to support the charging or the electric motor Regeneration of electrical power using exhaust gas energy to cause.

The object of the invention is now based, a control device and a control method for an internal combustion engine to provide that enable that with a forced enrichment of the air-fuel ratio of the exhaust gas and release of NOx (nitrogen oxide) from a NOx storage material NOx (during a rich tip action or the like) made of the NOx storage material NOx reliable and released quickly.

This task is solved by a control device with the features of claim 1 or a control method with the Mermkalen of claim 7. Preferred embodiments are subject to Expectations.

Claim 1 relates to a control device for one Internal combustion engine with one in an exhaust pipe of the internal combustion engine provided NOx storage material that stores NOx when that Air-fuel ratio of the inflowing Exhaust gas is lean and releases stored NOx when the air-fuel ratio of the Exhaust gas rich or stoichiometric is, a turbocharger provided on the internal combustion engine, a Electric motor driven by the turbine-compressor unit of the turbocharger change the boost pressure and Regenerate electrical power using the exhaust gas energy can, and an electric motor control device for driving the Electric motor and performing a controller for the regeneration of electrical power. The Electric motor control device controls the electric motor so that the in the internal combustion engine Air quantity to be sucked is reduced if the exhaust gas / air / fuel ratio is greased and released NOx stored from the NOx storage material becomes.

The claim 7 relates to a control method for an internal combustion engine with a vorese in an exhaust pipe of the internal combustion engine The NOx storage material that stores NOx when the air-fuel ratio of the exhaust gas of the incoming exhaust gas is lean and releases stored NOx when the air-fuel ratio of the exhaust gas is rich or stoichiometric is provided on the internal combustion engine Turbocharger and an electric motor, which can change the boost pressure by driving the turbine-compressor unit of the turbocharger and regenerate electrical power using the exhaust gas energy. According to the method according to the invention, the electric motor is controlled in such a way that the amount of air to be sucked into the internal combustion engine is reduced when the exhaust gas / air / fuel ratio is greased and NOx stored from the NOx storage material is released.

By means of those described above Control device and the control method described above for one Internal combustion engine can by reducing the amount of intake air using the Electric motor with a forced enrichment of the air-fuel ratio of the Exhaust gas and a release of NOx from the NOx storage material the air-fuel ratio of the Exhaust gas faster and more reliably change to a rich air-fuel ratio and thus the effect of the NOx removal quickly and reliably receive. If the intake air volume is reduced by reducing the Electric motor to be fed electrical power is reduced, unnecessary consumption prevent electrical energy and therefore the energy efficiency increase. With an increase the electrical power regenerated by the electric motor can be regenerate more electrical power and therefore the energy efficiency increase further.

The one to be sucked into the internal combustion engine The amount of air can therefore be reduced in that the electric motor supplied electrical power is reduced.

The in the internal combustion engine too The amount of air sucked in can be reduced in particular by that the electrical to be supplied to the electric motor Power quantity is reduced to zero.

If the electrical to be supplied to the electric motor Power is zero, the electric motor is used for regeneration caused by electrical power.

The one to be sucked into the internal combustion engine Air volume can be reduced by changing the amount of air Electric motor regenerated electrical power is increased.

Furthermore, the electric motor control device have the function of opening to control the throttle valve of the internal combustion engine and to reduce it the opening of the intake air volume reduce the throttle valve.

The exemplary embodiments presented above and other embodiments, features and advantages and the commercial importance of this invention emerge from the following detailed description of examples embodiments the invention with reference to the accompanying drawings, in which:

1 4 is a schematic representation of the configuration of an internal combustion engine with a control device according to an embodiment of the invention; and

2 10 is a flowchart of an electric motor controller according to an embodiment of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

An embodiment of a control device according to the invention is explained below with reference to the accompanying drawings. 1 shows an internal combustion engine 1 with a control device according to the embodiment.

The internal combustion engine 1 according to the embodiment is a multi-cylinder internal combustion engine. In 1 only one of the cylinders is shown. In the internal combustion engine 1 is by means of an injector 2 Fuel on the piston crown of a piston 4 in a cylinder 3 injected. In the internal combustion engine 1 stratified charge combustion can take place. The internal combustion engine 1 is a so-called lean-burn engine. Stronger charging by means of the turbocharger explained below and lean-burn combustion can not only achieve high performance but also high fuel efficiency.

In the internal combustion engine 1 is via an intake pipe 5 in the cylinder 3 air drawn in by a piston 4 compresses fuel into one on the piston crown of the piston 4 trained cavity injected, and a rich air-fuel mixture near a spark plug 7 enriched and for combustion by the spark plug 7 inflamed (ie stratified charge combustion takes place). if the fuel injection takes place during the intake stroke, normal homogeneous combustion can take place. An inlet valve 8th establishes a connection between the cylinder 3 and the suction pipe 5 or breaks this connection. The exhaust gas generated during combustion is fed into an exhaust pipe 6 pushed out. An exhaust valve 9 establishes a connection between the cylinder 3 and the exhaust pipe 6 or breaks this connection. In the intake line 5 are an air filter in the downstream direction 10 , an air flow meter 27 , (a turbocharger unit or) a turbocharger 11 , a charge air cooler 12 , a throttle valve 13 and the like.

The air filter 10 is a filter for removing dirt and dust in the intake air. The air flow meter 27 in the embodiment is a hot wire airflow meter that detects the intake air amount as a mass flow. The turbocharger 11 is between the suction pipe 5 and the exhaust pipe 6 provided and carries out a charging. In the turbocharger 11 a turbine wheel and a compressor wheel are connected via a rotary shaft (hereinafter this arrangement is simply referred to as a "turbine-compressor unit 11a '' designated).

The turbocharger 11 is in the embodiment as a turbocharger with an electric motor 11b which is integrated so that the rotary shaft of the turbine-compressor unit 11a as the output shaft of the electric motor 11b serves. The electric motor 11b can act as an electrical generator that generates electrical power using exhaust gas energy. The turbocharger 11 can also function as a normal turbocharger, which only performs a charge using the exhaust gas energy. The turbocharger 11 can also be charged by a positive drive of the turbine-compressor unit 11a by means of the electric motor 11b carry out.

It is also possible to drive the electric motor 11b via the turbine compressor unit 11a to generate electrical power using the exhaust gas energy in a regenerative manner and to recover the electrical power thus generated. The electric motor 11b essentially comprises one on the rotary shaft of the turbine-compressor unit 11a attached rotor and a stator provided on the circumference of the rotor. Downstream of the turbocharger 11 is in the suction line 5 the air-cooled intercooler 12 provided that reduces the temperature of the intake air. The temperature is the increase in pressure due to turbocharger charging 11 increased accordingly. The temperature of the intake air is determined by the charge air cooler 12 reduced to increase charging efficiency.

Downstream of the intercooler 12 is the throttle valve 13 provided that adjusts the amount of intake air. The throttle valve 13 is in the embodiment a so-called electronically operated throttle valve. The degree of operation of an accelerator pedal 14 is from an accelerator pedal position sensor 15 detected. An ECU 16 defines the opening of the throttle valve 13 based on the detection result and other information. The throttle valve 13 is by one on the throttle valve 13 attached servomotor 17 open closed. Furthermore, is on the throttle valve 13 a throttle position sensor 18 attached to the opening of the throttle valve 18 detected.

Downstream of the throttle valve 13 is a pressure sensor 19 provided the pressure (ie boost pressure / intake pressure) in the intake line 5 detected. The sensors 15 . 18 . 19 . 27 are connected to the ECU 16 and submit to the ECU 16 the acquisition results. The ECU 16 is an electronic control unit which is basically provided with a CPU, ROM, RAM and the like. The injector 2 who have favourited Spark Plug 7 , the electric motor 11b and the like are connected to the ECU 16 and are sent via signals from the ECU 16 driven. They also have an adjustable valve control mechanism 2 that determines the opening / closing timing of the intake valve 8th controls, one with the electric motor 11b connected control unit 21 , a battery 22 and the like with the ECU 16 connected.

The control unit 21 has both the function of a rectifier / inverter for converting the voltage from the electrical power due to the regeneration of electrical power by means of the electric motor 11 is obtained, as well as the function of controlling the drive of the electric motor 11b , The electrical power obtained as a result of the regeneration of electrical power is after the voltage conversion by the control unit 21 the battery 22 fed. In the exhaust pipe 6 is upstream of the turbocharger 11 an air-fuel ratio sensor 28 provided for detecting the air-fuel ratio of the exhaust gas. The air-fuel ratio sensor 28 is connected to the ECU 16 and transmits the results of the acquisition. The air-fuel ratio sensor 28 is a so-called linear air-fuel ratio sensor in the embodiment, which can linearly detect the air-fuel ratio from the lean air-fuel ratio range to a rich air-fuel ratio range.

Downstream of the turbocharger 11 is an exhaust gas purification catalyst 23 intended. The exhaust gas purification catalyst 23 is a normal three-way catalytic converter in the exhaust pipe 6 is provided in an upstream area. The temperature of the exhaust gas purification catalyst 23 is increased more rapidly due to the temperature of the exhaust gas during a cold start to the temperature at which the exhaust gas purification catalyst is in an active work area, whereby the catalytic function can be maintained quickly. Downstream of the exhaust gas purification catalyst 23 is a NOx storage reduction exhaust gas purifying catalyst (hereinafter simply referred to as "NOx storage reduction catalyst") 29 intended. The NOx storage reduction catalyst 29 is created by further providing a NOx storage material on the three-way catalytic converter. The NOx storage reduction catalyst 29 has both the function of a normal three-way catalytic converter and the function of the NOx storage material. The NOx storage reduction catalyst 29 therefore acts in particular as the NOx storage material.

The NOx storage reduction catalyst 29 is created by, in addition to noble metals such as platinum, palladium and rhodium, alkali metals (for example K, Na, Li, Cs), alkaline earth metals (for example Ba, Ca) and. on a carrier whose surface is coated with a thin layer of aluminum oxide Rare earth metals (e.g. La, Y) can be provided. The NOx storage reduction catalyst 29 can store NOx contained in the exhaust gas when the engine is at a. lean air-fuel ratio is operated. Therefore, the NOx storage reduction catalyst 29 Both the function of storing and not reducing the NOx contained in the exhaust gas as well as the function of a three-way catalytic converter, ie the function of HC, CO and NOx contained in the exhaust gas, which occurs during combustion at an air-fuel ratio in the Close to the stoichiometric air-fuel ratio occurs.

That in the NOx storage reduction catalyst 29 stored NOx is released when combustion takes place at a rich or stoichiometric air-fuel ratio, and reduced for decomposition by HC and CO contained in the exhaust gas (during this process, HC and CO are oxidized and thus also reduced). If it is established that the amount of the NOx storage reduction catalyst 29 stored NOx comes close to the storage capacity, for example if the operation in the lean combustion area continues, the so-called enrichment peak action can accordingly be forcibly carried out by briefly operating the internal combustion engine with a rich air-fuel ratio in order to reduce stored NOx.

An EGR (ie exhaust gas recirculation) line is also provided 24 for returning exhaust gas from the exhaust pipe 6 (ie, the upstream side of the air-fuel ratio sensor 28 ) in the suction line 5 (ie one downstream of a pressure sensor 19 trained expansion tank). On the EGR line 24 is an EGR valve 25 provided to adjust the amount of exhaust gas recirculation. The opening of the EGR valve 25 is through the ECU 16 controlled. Near the crankshaft of the internal combustion engine 1 is a crankshaft position sensor 26 provided for detecting the rotational position of the crankshaft. The crankshaft position sensor 26 can detect the engine speed depending on the position of the crankshaft.

The internal combustion engine control system according to the invention is described below. 2 10 shows a flowchart of the control according to the embodiment.

The control in the in 2 The flowchart shown is performed in parallel with an air-fuel ratio control and a normal electric motor control. The electric motor control illustrated in the flowchart is performed by an interruption of the normal electric motor control. In normal electric motor control, the degree of support from the electric motor is boosted 11b (ie the amount of the electric motor 11b electrical power to be supplied) is determined on the basis of a target and actual boost pressure and the electric motor 11b causes, instead of a regeneration of electrical power, charging support depending on the operating state of the internal combustion engine 1 perform. The ECU 16 cooperates with the control unit 21 and controls the electric motor 11b on. The ECU 16 and the control unit 21 act as an electrical control device.

First, it is determined (S200) whether there is a request for a peaking action (hereinafter referred to as a "peaking action request"). A peak enrichment action request occurs while the air-fuel ratio control is running. In the aforementioned air-fuel ratio regulation / control, an enrichment peak action can be carried out. This leads to a request for enrichment peaks depending on which fuel injection quantity is controlled. If necessary, the intake air volume through the throttle valve 13 or the exhaust gas recirculation amount through the EGR valve 25 controlled. For example, if operation continues in the lean-burn region, NOx in the NOx storage reduction catalytic converter 29 enriched. Accordingly, if the operation of the internal combustion engine 1 continues in the lean-burn region for several tens of seconds, an enrichment peak action is carried out over several tenths of a second up to one second.

if there is no enrichment peak action request, control is according to the in 2 shown flowchart to the end. On the other hand, if there is a request for an enrichment peak action, it is first determined (S210) whether the electric motor 11b in such a way that it is driven by the control unit 21 is controlled, and then the amount of intake air is reduced. The fact that the electric motor 11b is driven means the electric motor 11b is supplied with electrical power and supports charging. Therefore, if an affirmative answer is obtained in step S210, the supply of electric power to the electric motor 11b and the charging support caused thereby by the electric motor 11b interrupted (S220). The regeneration of electrical power is then initiated (S230).

By interrupting the charging support and initiating the regeneration of electrical power, the rotation of the turbine-compressor unit is stopped 11a resistance is opposed, thereby reducing the amount of intake air. By reducing the amount of intake air during the peak enrichment action, the degree of enrichment can be increased further and a larger amount of NOx can be released reliably. In the embodiment, this becomes the NOx storage reduction catalyst 29 released NOx through the NOx storage reduction catalyst 29 self-dismantled. Because the intake air quantity directly through the control of the electric motor 11b is reduced, the state in which the air-fuel ratio is rich can be quickly realized. Accordingly, the effect of the greasing tip action comes to light quickly.

On the other hand, if a negative answer is obtained in step S210, it is then determined (S240) whether the regeneration of electrical power by the electric motor is already in progress 11b takes place. If a negative answer is obtained in step S240, that is, if neither charging support nor regeneration of electrical power by the electric motor 11b regeneration of electrical power is initiated (S230), thereby reducing the intake air volume. In this case too, the effect of the greasing tip action can be obtained reliably and quickly. If an affirmative answer is obtained in step S240, the amount of electric power regeneration is increased (S250). As in the case of the embodiment, in the event that the control unit 21 performs variable control of the amount of electric power regeneration, the amount of intake air is reduced, for example, by increasing the amount of electric power regeneration.

If a maximum amount of electrical power is already being generated, the throttle valve may open 13 are reduced, etc. The regeneration of electric power initiated in step S230 or the regeneration of electric power, the power generation amount of which was increased in step S250, continues over a predetermined time (S260). The predetermined time can be determined, for example, on the basis of the enrichment peak action time. If the air-fuel ratio changes quickly to a rich air-fuel ratio anyway, the current state can of course also be maintained. Accordingly, a sufficient effect can only be obtained by, as in the case of the embodiment, reducing the amount of intake air using the electric motor 11b over the predetermined time and changing the air-fuel ratio to a rich air-fuel ratio. The optimal time is determined experimentally and set in advance as the predetermined time. Furthermore, the predetermined time can have a fixed value or can be regulated in such a way that it is dependent on the boost pressure and the degree of enrichment (the air-fuel ratio during the enrichment peak action, the difference in the air-fuel ratios before and after the enrichment peak action or the like) is changeable.

After the amount of intake air is reduced by the electric motor 11b the process returns to the normal state over the specified time (S270). Specifically, as explained above, the amount of support for charging by the electric motor 11b (ie, that of the electric motor 11b amount of electric power to be supplied) is decided on the basis of the target and actual boost pressure; the electric motor continues 11b based on the boost assist control depending on the condition of the internal combustion engine 1 instead of the control that causes the electric motor 11b to regenerate electric power. Thereafter, when the spike action is performed again, that in the flowchart of 2 shown control performed. In the embodiment, the electric power regeneration is initiated and the amount of electric power regeneration corresponding to the reduction in the amount of intake air by the electric motor 11b elevated. Accordingly, the advantage is achieved that the energy efficiency can be increased by the regeneration of electrical power.

During the enrichment peak action, a sudden or step-like change in the output torque of the internal combustion engine can occur 1 result. In particular, when the rich spike action is performed during operation in the lean-burn region, the air-fuel ratio changes abruptly from a lean air-fuel ratio to a rich air-fuel ratio. Accordingly, there is a likelihood that a moment jump will be noticeable. Therefore, in the embodiment, the ignition timing is adjusted (in the late direction) such that the output torque before and after the enrichment peak action is essentially unchanged.

However, the invention is not limited to the embodiment explained above. In the embodiment explained above, for example, in the case where the enrichment peak action is carried out (ie in the case where the air-fuel ratio of the exhaust gas is forcedly enriched and NOx is released from the NOx storage material), when the electric motor 11b of the turbocharger is driven (ie, when boost assistance takes place), the electric motor 11b stopped and the regeneration of electrical power initiated. However, since the effect of reducing the intake air quantity can also be obtained solely by interrupting the drive of the electric motor, it is also possible to stop only the driven electric motor.

Furthermore, the NOx storage material stores (ie the NOx storage reducti ons catalyst) tend to be SOx (sulfur oxide) more permanent than NOx. Therefore, a sulfur component contained in the fuel or engine oil is stored in the NOx storage reduction catalyst as SOx, with the result that the capacity for storing NOx is reduced, which can cause so-called SOx poisoning. In order to avoid SOx poisoning, however, the greasing tip action can be carried out. This enrichment spike action releases both NOx and SOx. Accordingly, the reduction in the amount of intake air by appropriate control of the electric motor 11b in any case forms an essential part of the invention.

A control device according to the invention for an internal combustion engine therefore comprises a NOx storage material (for example the NOx storage reduction catalyst). 29 that stores NOx when the air-fuel ratio of the exhaust gas of the incoming exhaust gas is lean and releases stored nitrogen oxide NOx when the air-fuel ratio of the exhaust gas of the incoming exhaust gas is rich or stoichiometric, one at the internal combustion engine 1 provided turbocharger 11 , an electric motor 11b that boost pressure by driving the turbine compressor unit 11a of the turbocharger 11 change and regenerate electrical power using the exhaust gas energy, and an electric motor control device 16 . 21 to control the electric motor 11b that the electric motor 11b controls so that the amount of intake air is reduced when the air-fuel ratio of the exhaust gas is greased and in the NOx storage material 29 stored NOx is released. This control device or the control method carried out by the control device enable the reliable release of NOx from the NOx storage material.

It should be noted that the term "storage" here the restraint a substance (solid, liquid, gaseous molecules) through adsorption, adhesion, Absorption, trapping, occlusion and / or the like means.

Claims (12)

Control device for an internal combustion engine comprising: one in an exhaust pipe ( 6 ) of the internal combustion engine ( 1 ) provided NOx storage material ( 29 ) that stores NOx when the exhaust gas air-fuel ratio of the incoming exhaust gas is lean and releases NOx when the exhaust gas air fuel ratio is rich or stoichiometric at the internal combustion engine ( 1 ) provided turbocharger ( 11 ), an electric motor ( 11b ), which is driven by a turbine-compressor unit ( 11a ) of the turbocharger ( 11 ) can change the boost pressure and regenerate electrical power using the exhaust gas energy, and an electric motor control device ( 16 . 21 ) to drive the electric motor ( 11b ) and performing a control for the regeneration of electrical power, characterized in that the electric motor control device ( 16 . 21 ) the electric motor ( 11b ) controls so that the in the internal combustion engine ( 1 ) the amount of air to be sucked in is reduced if the exhaust gas / air / fuel ratio is greased and made of the NOx storage material ( 29 ) stored NOx is released. Internal combustion engine control device according to claim 1, characterized in that the electric motor control device ( 16 . 21 ) the amount of the electric motor ( 11b ) electrical power to be supplied is reduced to the internal combustion engine ( 1 ) reduce the amount of air to be sucked in. Internal combustion engine control device according to claim 1 or 2, characterized in that the electric motor control device ( 16 . 21 ) the amount of the electric motor ( 11b ) to be reduced to zero electrical power to be fed into the internal combustion engine ( 1 ) reduce the amount of air to be sucked in. Internal combustion engine control device according to claim 3, characterized in that the electric motor control device ( 16 . 21 ) the electric motor ( 11b ) can regenerate electrical power if the amount of the electric motor ( 11b ) electrical power to be supplied is reduced to zero. Internal combustion engine control device according to claim 1, characterized in that the electric motor control device ( 16 . 21 ) the amount of the electric motor ( 11b ) regenerated electrical power increases to the in the internal combustion engine ( 1 ) reduce the amount of air to be sucked in. Internal combustion engine control device according to claim 5, characterized in that the electric motor control device ( 16 . 21 ) also has the function of opening a throttle valve ( 13 ) of the internal combustion engine ( 1 ) and the opening of the throttle valve ( 13 ) of the internal combustion engine ( 1 ) reduced. Control method for an internal combustion engine with an in an exhaust pipe ( 6 ) of the internal combustion engine ( 1 ) provided NOx storage material ( 29 ) that stores NOx when the exhaust gas air-fuel ratio of the incoming exhaust gas is lean and releases NOx when the exhaust gas air fuel ratio is rich or stoichiometric at the internal combustion engine ( 1 ) provided turbocharger ( 11 ) and an electric motor ( 11b ), which is driven by a turbine compressor ter unit ( 11a ) of the turbocharger ( 11 ) can change the boost pressure and regenerate electrical power using the exhaust gas energy, characterized in that the electric motor ( 11b ) is controlled so that the in the internal combustion engine ( 1 ) the amount of air to be sucked in is reduced if the exhaust gas / air / fuel ratio is greased and made of the NOx storage material ( 29 ) stored NOx is released. Internal combustion engine control device according to claim 7, characterized in that the amount of the electric motor ( 11b ) electrical power to be supplied is reduced. Internal combustion engine control device according to claim 7 or 8, characterized in that the amount of the electric motor ( 11b ) electrical power to be supplied is reduced to zero. Internal combustion engine control device according to claim 9, characterized in that the electric motor ( 11b ) is caused to regenerate electrical power when the amount of the electric motor ( 11b ) electrical power to be supplied is reduced to zero. Internal combustion engine control device according to claim 7, characterized in that the amount of the electric motor ( 11b ) regenerated electrical power is increased. Internal combustion engine control device according to claim 11, characterized in that the opening of the throttle valve ( 13 ) of the internal combustion engine ( 1 ) is reduced.