DE102013201177A1 - Internal combustion engine system i.e. petrol engine system, for operating motor car, has pressure tank storing compressed fresh air, and air valve provided in cylinder for introducing fresh air from tank into combustion chamber - Google Patents

Abstract

The system (1) has a cylinder (3) provided with a combustion chamber (31) for performing combustion of an air/fuel mixture, and a fuel injection valve (6) for injecting fuel. A pressure tank (11) stores compressed fresh air, and an air valve (10) is provided in the cylinder for introducing the compressed fresh air from the pressure tank into the combustion chamber of the cylinder. A compressor (12) fills a pressure tank with the compressed fresh air, and is driven by energy sources e.g. electric motor (13), stirling motor and exhaust gas-driven turbine. The pressure tank is made of metal and/or fiber-glass/composite material.

Description

Technical area

The present invention relates to engine systems with internal combustion engines, in particular measures for supplying fresh air into combustion chambers of an internal combustion engine.

State of the art

In conventional internal combustion engines, air is supplied via an air supply section. Particularly in gasoline engines, the fresh air flowing into the combustion chambers of the cylinders results from the intake effect caused by a piston movement in the cylinders of the internal combustion engine. The amount of fresh air sucked by the piston movement in the cylinders is controlled by a throttle valve provided in the air supply portion, so that the amount of air existing in the combustion chambers of the cylinders for the pending combustion can be adjusted.

In order to improve the dynamic response of internal combustion engines increasingly exhaust gas driven charging devices are provided, which support the promotion of fresh air into the combustion chambers of the cylinder.

Disclosure of the invention

According to the invention, an engine system with an internal combustion engine according to claim 1 are provided.

Further advantageous embodiments of the present invention are specified in the dependent claims.

• – mindestens einen Zylinder mit einem Brennraum zum Durchführen einer Verbrennung eines Luft-/Kraftstoffgemischs;
• – ein Kraftstoffeinspritzventil zum Einspritzen von Kraftstoff, insbesondere in den Brennraum des Zylinders;
• – einen Druckbehälter zum Speichern von komprimierter Frischluft;
• – jeweils mindestens ein Luftventil pro Zylinder zum Einlassen von komprimierter Frischluft aus dem Druckbehälter in den Brennraum des betreffenden Zylinders.

According to a first aspect, an engine system is provided with an internal combustion engine. The engine system includes:

• - At least one cylinder with a combustion chamber for carrying out combustion of an air / fuel mixture;
• A fuel injection valve for injecting fuel, in particular into the combustion chamber of the cylinder;
• A pressure vessel for storing compressed fresh air;
• - Each at least one air valve per cylinder for admitting compressed fresh air from the pressure vessel into the combustion chamber of the cylinder in question.

The previous method of supplying fresh air to the cylinders of an internal combustion engine has a number of disadvantages:

The fresh air supply via the intake manifold has in the dynamic operation of the internal combustion engine a relatively slow dynamic behavior of the amount of air admitted into the cylinder.

Furthermore, a conventional internal combustion engine has the disadvantage that the components present in the air supply section cause energy losses. Thus, for example, the intake of fresh air caused by the piston movement in the combustion chambers of the cylinder charge exchange losses and the operation of the camshaft for the valve clearance generates additional friction losses.

Using an exhaust gas driven supercharger to provide an increased pressure of the fresh air to be supplied, additional residual energy of the combustion exhaust gas is used to drive the supercharger, resulting in increased exhaust backpressure and thus also reducing the power of the engine.

Further disadvantages in the use of the conventional air supply system consist in the inaccuracy of Beimessung the flowing into the combustion chambers of the cylinder air flow, so that a complex exhaust aftertreatment is necessary.

One idea of the above engine system is to provide a compressed air reservoir from which the amount of fresh air needed to operate the internal combustion engine is taken. As a result, the previous disadvantages of internal combustion engines, which are associated with the slow dynamic behavior of the air system in the dynamic operation of the internal combustion engine, can be avoided.

The use of a compressed air reservoir as a source of the fresh air required for the combustion has the advantage that fresh air in the required amount can be introduced directly into the combustion chambers of the cylinder or can flow. The Beimessung the fresh air into the combustion chambers of the cylinder can be done by simple air valves and components such as throttle or a charging device are no longer necessary. The amount of injected fresh air can be adjusted by the opening time of the air valves.

The decompression of the air flowing from the pressure vessel into the combustion chambers of the cylinder leads to a cooling, so that the combustion chambers of the cylinders can be cooled accordingly. This improves the knocking behavior of the internal combustion engine. In addition, it is possible for the amount of air to be injected for the combustion in the combustion chambers of the cylinder cylinder-individual What can be useful for HCCI (Homogeneous Charge Compression Ignition) operation?

Furthermore, by the above engine system, the number of required for determining the reaching into the combustion chambers fresh air sensors can be significantly reduced. Thus, the commonly used sensors, namely hot air mass sensor, throttle position sensor, angle sensor for the intake camshaft, other pressure and temperature sensors and the like when using the pressure vessel as a source of fresh air are no longer necessary. Instead, one could get along for the determination of the exact Beimessung the fresh air into the cylinder with a pressure and a temperature sensor for the fresh air compressed in the pressure vessel.

Furthermore, the volume of the pressure vessel may exceed 10 times the total volume of the cylinders of the internal combustion engine.

According to one embodiment, a compressor may be provided to fill the pressure vessel with compressed fresh air.

In particular, the compressor can be driven by a plurality of energy sources, in particular by an electric motor and / or a Stirling engine and / or an exhaust-driven turbine.

Furthermore, the Stirling engine may have a first air cylinder coupled to an exhaust discharge section of the internal combustion engine and a second air cylinder thermally insulated from the first air cylinder.

Furthermore, an air conditioning valve may be provided to extract compressed compressed fresh air from the pressure vessel, to decompress and to provide the decompression cooled fresh air for cooling.

Furthermore, a control unit may be provided to control the injection valve and the air valve so that an air / fuel mixture is formed before a combustion cycle.

It can be provided that one or more auxiliary pressure vessels are coupled to the pressure vessel in order to increase the storage volume for compressed air. In particular, the secondary pressure vessel may have a variable volume.

According to a further aspect, the secondary pressure vessel is coupled to the pressure vessel via a one-way valve so that compressed air from the secondary pressure vessel flows into the main pressure vessel as soon as the pressure of the compressed air in the secondary pressure vessel is higher or higher by a certain amount than in the main pressure vessel.

According to a further embodiment, the secondary pressure vessel may be coupled via a pressure-controlled valve to the pressure vessel, wherein the pressure-controlled valve opens as soon as the pressure in the main pressure vessel exceeds a predetermined absolute value.

It can be provided that the secondary pressure vessel is coupled via an electronically controllable valve with the pressure vessel, wherein a control unit is provided to control the electronically controllable valve so that compressed air flows from the secondary pressure vessel in the main pressure vessel as soon as the pressure of the compressed air in the Secondary pressure vessel is higher or higher by a certain amount than in the main pressure vessel, and / or that the pressure-controlled valve is opened when the pressure in the main pressure vessel exceeds a predetermined absolute value.

Brief description of the drawing

Preferred embodiments of the present invention will be explained in more detail with reference to the accompanying drawings. It shows:

1 a schematic representation of an engine system with an internal combustion engine, the air is supplied via a pressure vessel;

2 a schematic representation of another engine system with an internal combustion engine, the air is supplied via a pressure vessel and a secondary pressure vessel;

3 a schematic representation of another engine system with an internal combustion engine, the air is supplied via a pressure vessel and a secondary pressure vessel;

4 a schematic representation of another engine system with an internal combustion engine, the air is supplied via a pressure vessel and a secondary pressure vessel.

Description of embodiments

1 shows a schematic representation of an engine system 1 with an internal combustion engine 2 (In the embodiment shown, a gasoline engine), of which by way of example a cylinder 3 is shown. The engine system 1 serves for example for operating a (not shown) motor vehicle. The cylinder 3 includes a combustion chamber 31 , which at one end by a movable piston 32 is completed.

At one the piston 32 opposite cylinder head 33 is an ignition device 5 provided in a combustion stroke in the combustion chamber 31 of the cylinder 3 Ignite air / fuel mixture located and thereby an expansion movement of the piston 32 to effect.

Furthermore, a fuel injection valve 6 provided to fuel directly into the combustion chamber 31 of the cylinder 3 inject. In an exhaust stroke following the combustion stroke becomes an exhaust valve 7 in the cylinder head 33 opened and combustion exhaust gas via a Abgasabführungsabschnitt 8th pushed out.

Via an air valve 10 becomes the internal combustion engine 2 Fresh air is supplied from a pressure vessel 11 is removed. The pressure vessel 11 is located in an area of the motor vehicle that has an ambient temperature or a temperature that is significantly lower than the temperature near the engine. The pressure vessel 11 may be formed, for example, of metal and / or of a fiberglass and / or composite material. In particular, glass fiber material has the advantages of low weight or high compressive strength.

Due to the pressure difference between the pressure vessel 11 and the combustion chamber 31 of the cylinder 3 the air flows when opening the air valve 10 in the combustion chamber 31 and relaxes here. This will make the cylinder 3 cooled as the expanding air cools.

The control of the air valve 10 , the ignition device 5 , the fuel injection valve 6 and the exhaust valve 7 is from a control unit 15 controlled. The control of the internal combustion engine 2 is essentially similar to the control of a conventional internal combustion engine, with only the opening of the air valve 10 for admitting a certain amount of air is made so that a predetermined, z. B. a possible stoichiometric, combustion of the air / fuel mixture in the combustion chamber 31 of the cylinder 3 can be done.

The dimension of the amount of fresh air to be injected into the combustion chamber can be determined by providing opening times for the air valves 10 be made, the control unit 15 about one on the pressure vessel 11 arranged pressure and temperature sensor 9 corresponding state variables in the pressure vessel 11 and from this the corresponding opening times of the air valves 10 can determine.

The loading of the pressure vessel 11 with compressed air via a compressor 12 which is either electric motorized by means of an electric motor 13 or can be driven by another source of energy. The compressor 12 sucks fresh air through an air filter 16 on, compresses them and passes the compressed fresh air through a cooling device 17 for cooling the compressed fresh air into the pressure vessel 11 ,

By the compression of the fresh air in the pressure vessel 11 remove the resulting compression heat, the pressure vessel 11 continue to be provided with a cooling device, eg with cooling fins. As a result, the heat generated there is dissipated into the environment.

Depending on the size of the pressure vessel 11 An additional use for an air conditioner can be provided, since the over an air conditioning valve 18 from the pressure vessel 11 Exhausted air cools due to their expansion and thus would be suitable for cooling the passenger compartment of a motor vehicle.

In the present embodiment, the compressor 12 continue via a Stirling engine 19 operated, the temperature difference between the exhaust side of the engine 2 and the environment uses a mechanical drive of the compressor 12 to reach.

The Stirling engine 19 Includes two air cylinders, each using a connecting rod with a drive wheel 20 are connected. A first air cylinder 22 is near the exhaust removal section 8th arranged there to absorb the heat of the combustion exhaust gas. The heat of the combustion exhaust gas is preferably via cooling fins 21 in the exhaust discharge portion 8th extracted from the combustion exhaust gas and the first air cylinder 22 of the Stirling engine 19 fed.

By the heat removed from the combustion exhaust gas expands in the first air cylinder 22 located air volume and causes a force on a first connecting rod 25 , causing the drive wheel 20 is driven. During a compression movement of the piston in the first air cylinder 22 is the heated air through a regenerator 23 in a second air cylinder 24 pressed, which is remote from the motor and is thus in an environment with ambient temperature.

As the operating speeds of a Stirling engine 19 compared to that of the compressor 12 For the compression of fresh air required speed is low, a suitable translation must be provided to those of the Stirling engine 19 increase the speed provided.

The one from the first air cylinder 22 in the second air cylinder 24 transported air has a high temperature and is in the second air cylinder 24 , which may be provided in accordance with cooling fins, cooled, whereby the pressure in the cylinder chamber decreases and a corresponding movement of the piston of the second air cylinder 24 causes. This movement is via a second connecting rod 27 to the drive wheel 20 forwarded.

In essence, the operation of the Stirling engine 19 Reference is made to the prior art and will be omitted herein for a more detailed description.

The use of the temperature of the combustion exhaust gas leads to no increased exhaust backpressure and thus not to a loss of efficiency during operation of the internal combustion engine 2 ,

Should have the compression performance of the Stirling engine 19 is not provided to maintain a pressure in the pressure vessel 11 sufficient, so can the electric motor 13 be switched on. This also applies to the warm-up operation of the internal combustion engine 2 in which there is insufficient temperature difference to the operation of the Stirling engine 19 is available.

The pressure vessel 11 represents a reservoir for all cylinders 3 of the internal combustion engine 2 dar. The volume of the pressure vessel 11 is preferably in proportion to the combustion chamber volume of the cylinder 3 of the internal combustion engine 2 chosen big. Preferably, the volume of the pressure vessel should be 11 at least 10 times the total maximum combustion chamber volume of all cylinders 3 be. The air pressure inside the pressure vessel 11 should be during operation of the internal combustion engine 2 at least 10 bar, preferably 20 bar, to allow a sufficiently fast intake of fresh air into the cylinder 3 to reach. It can be provided, depending on the requested load, the air pressure in the pressure vessel 11 adapt.

Alternatively or in addition to the Stirling engine 19 can also drive other power sources for the compressor 12 can be used, such as a turbine for converting the exhaust gas enthalpy of the combustion exhaust gas, as used for example in an exhaust gas driven supercharger (turbocharger).

The first air cylinder 22 of the Stirling engine 19 is to the Abgasabführungsabschnitt 8th coupled, wherein heat conduction fins in Abgasabführungsabschnitt 8th are provided to receive the heat of the combustion exhaust gas and the first air cylinder 22 be forwarded. By suitable shaping of the heat conduction fins and by a catalytic coating, the function of the catalyst with the function of heat transfer to the first air cylinder 22 of the Stirling engine 19 be combined.

Between the pressure vessel 11 and the second air cylinder 24 of the Stirling engine 19 and the internal combustion engine 2 and the first air cylinder 22 of the Stirling engine 19 can be a thermal insulation 28 be provided to ensure that the pressure vessel 11 and the second air cylinder 24 of the Stirling engine 19 not by the waste heat of the internal combustion engine 2 to be heated.

When choosing the volume of the pressure vessel 11 It should be borne in mind that with a lower volume, the regulation of the maximum pressure in the pressure vessel 11 faster is possible. Furthermore, less energy is needed for the first charge before engine start to the pressure vessel 11 to replenish to an operating pressure. Furthermore, in a smaller pressure vessel 11 less energy stored in the form of compressed air, so that effects of any explosion in case of damage to the printing system are reduced.

By contrast, the pressure vessel should 11 have a sufficiently large volume to provide the longest possible discharge time, without additional compressed air is provided. This makes it possible to stop the compression for a short time. Furthermore, allows a larger pressure vessel 11 the adaptation to the longer time constant when the energy for the compressor 12 obtained from thermal recovery systems.

The above configuration sees a pressure vessel 11 whose volume is chosen so as to take into account the above-mentioned aspects.

In the in 2 illustrated embodiment, the pressure vessel is constructed in two parts. The pressure vessel 11 represents a main pressure vessel. Next to the main pressure vessel 11 is a secondary pressure vessel 41 provided, which is also designed for storing compressed air. The secondary pressure tank 41 is with the main pressure vessel 11 over a connecting line 45 connected in which a flow restrictor 46 is provided.

In the secondary pressure tank 41 is a cylinder plate 42 slidably provided, the internal volume of the pressure vessel 41 almost hermetically seals and the internal volume in the pressure vessel 41 can adapt variably. The cylinder plate 42 is by a spring 43 acted upon, so on the cylinder plate 42 a nearly constant force in the direction of a reduction of the volume of the pressure vessel 41 acts.

The flow limiter 46 limits the energy transfer in case of a strong pressure drop in one of the pressure vessels 11 . 41 , Furthermore, the effect of the spring 43 applied cylinder plate 42 that compressed air into the secondary pressure tank 41 flows as soon as a certain air pressure in the main pressure vessel 11 present, which is capable of the inner volume of the pressure vessel 41 expand. The volume in which the stored compressed air is stored, in this case automatically adapts to the amount of available compressed air.

At the secondary pressure tank 41 can be a position sensor 47 be provided, which suitably the position of the cylinder plate 42 detected and thus can determine what amount of air in the volume of the pressure vessel 41 is stored.

In 3 another embodiment is shown. In contrast to the embodiment of 2 is another secondary pressure vessel 51 provided, which is formed without a spring and cylinder plate. In addition to the flow limiter 46 is a one-way valve 47 and a pressure-controlled valve 48 in the connection line 45 are provided. The one-way valve 47 and the pressure-controlled valve 48 are arranged parallel to each other. The one-way valve 47 is adapted to the compressed air from the pressure vessel 41 in the main pressure vessel 11 to flow as soon as the pressure of the compressed air in the pressure vessel 41 is higher or higher by a certain amount than in the main pressure vessel 11 ,

The pressure-controlled valve 48 is designed to open as soon as the pressure in the main pressure vessel 11 exceeds a certain absolute value. Thus, the compressed air reaches the main pressure vessel 11 quickly their working pressure, due to the pressure threshold of the pressure-controlled valve 48 is predetermined, and then fills the pressure vessel 41 , This configuration has the advantage that the secondary pressure vessel 41 is easier and easier to train by eliminating the spring and cylinder plate. Therefore, the secondary pressure tank 41 , in particular its internal volume, assume any shape and can therefore be easily integrated into an existing engine system.

Another embodiment is in 4 shown. The additional secondary pressure tank 51 of the 3 is not about the one-way valve 47 and the pressure-controlled valve 48 but with an electronically controllable valve 49 with the main pressure vessel 11 connected. This electronically controlled valve 49 is from the control unit 15 controlled. The amount of air in the additional pressure tank 51 thus, depending on the pressure and temperature sensor 9 measured pressure in the main pressure vessel 11 to be controlled.

Regarding the embodiments of the 2 to 4 can the air conditioning valve 18 also directly with the pressure vessel 41 connected so that when using the air conditioner not the pressure of the compressed air in the pressure vessel 11 is reduced, but only the pressure in the pressure vessel 41 ,

Of course, in addition to the above-described secondary pressure vessels 41 . 51 also further in each case corresponding to the pressure vessel 11 and / or to the respective secondary pressure vessel 41 . 51 be coupled.

The design of storing the compressed air in several pressure vessels has the advantage that when the engine is started or when compressed air resumes with empty pressure vessels, the pressure in the pressure vessel quickly becomes high and thus usable 11 can be constructed when loading the pressure vessel 41 . 51 With compressed air is suppressed or delayed.

The thermal recovery systems, such as using the above Stirling engine 19 , typically have very high time constants. In case of load fall or braking, therefore, the case may occur that of the compressor 12 More compressed air is provided than can be supplied to the internal combustion engine. Conversely, when there is a load increase, there is a greater need for compressed air, which can only be provided with a delay because of the inertia of a thermal recovery system. To buffer the inertia of Druckluftbereitstellung a larger storage volume for the compressed air is appropriate.

Claims (13)

Engine system ( 1 ) with an internal combustion engine ( 2 ), comprising: - at least one cylinder ( 3 ) with a combustion chamber ( 31 ) for performing combustion of an air / fuel mixture; A fuel injection valve ( 6 for injecting fuel; - a pressure vessel ( 11 ) for storing compressed fresh air; - at least one air valve ( 10 ) per cylinder ( 3 ) for introducing compressed fresh air from the pressure vessel ( 11 ) into the combustion chamber of the cylinder ( 3 ). Engine system ( 1 ) according to claim 1, wherein the volume of the pressure vessel ( 11 ) 10 times the total volume of the cylinders ( 3 ) of the internal combustion engine ( 2 ) exceeds. Engine system ( 1 ) according to claim 1 or 2, wherein a compressor ( 12 ) is provided to the pressure vessel ( 11 ) with compressed fresh air to fill. Engine system ( 1 ) according to claim 3, wherein the compressor ( 12 ) is drivable by a plurality of energy sources, in particular by an electric motor ( 13 ) and / or a Stirling engine and / or an exhaust-driven turbine. Engine system ( 1 ) according to claim 4, wherein the Stirling engine ( 19 ) a first with a Abgasabführungsabschnitt ( 8th ) of the internal combustion engine ( 2 ) coupled first air cylinder ( 22 ) and a second, from the first air cylinder ( 22 ) thermally insulated arranged air cylinder ( 24 ) having. Engine system ( 1 ) according to one of claims 1 to 5, wherein an air conditioning valve ( 18 ) is provided to compressed fresh air from the pressure vessel ( 11 ), and to decompress the fresh air cooled by the decompression for cooling. Engine system ( 1 ) according to one of claims 1 to 6, wherein a control unit ( 15 ) is provided to the fuel injection valve ( 6 ) and the air valve ( 10 ) so that an air / fuel mixture is formed before a combustion cycle. Engine system ( 1 ) according to one of claims 1 to 7, wherein the fuel injection valve ( 6 ) for injecting fuel into the combustion chamber ( 31 ) of the cylinder ( 3 ) is provided. Engine system ( 1 ) according to one of claims 1 to 8, wherein one or more auxiliary pressure vessel are coupled to the pressure vessel to increase the storage volume for compressed air. Engine system ( 1 ) according to claim 9, wherein the secondary pressure vessel has a variable volume. Engine system ( 1 ) according to one of claims 9 and 10, wherein the secondary pressure vessel is coupled via a one-way valve to the pressure vessel, so that compressed air from the secondary pressure vessel flows into the main pressure vessel as soon as the pressure of the compressed air in the secondary pressure vessel is higher or at least a certain amount higher as in the main pressure vessel. Engine system ( 1 ) according to one of claims 9 to 11, wherein the secondary pressure vessel is coupled via a pressure-controlled valve to the pressure vessel, wherein the pressure-controlled valve opens when the pressure in the main pressure vessel exceeds a predetermined absolute value. Engine system ( 1 ) according to claim 9, wherein the secondary pressure vessel is coupled via an electronically controllable valve to the pressure vessel, wherein a control unit is provided to control the electronically controllable valve so that compressed air flows from the secondary pressure vessel into the main pressure vessel as soon as the pressure of the compressed air in the Secondary pressure vessel is higher or at least a certain amount higher than in the main pressure vessel, and / or that the pressure-controlled valve is opened when the pressure in the main pressure vessel exceeds a predetermined absolute value.

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