WO2014135200A1

WO2014135200A1 - Combustion engine comprising a linear generator and a return spring

Info

Publication number: WO2014135200A1
Application number: PCT/EP2013/054407
Authority: WO
Inventors: Johannes Wollenberg
Original assignee: Siemens Aktiengesellschaft
Priority date: 2013-03-05
Filing date: 2013-03-05
Publication date: 2014-09-12

Abstract

The invention relates to a combustion engine comprising a cylinder (1), in which a piston (2) of the combustion engine is linearly displaceable. The piston (2) oscillates in the cylinder (1) between a top dead centre (OT1) and a bottom dead centre (UT1). A first end face (3) of the piston (2) delimits a combustion chamber (4) of the combustion engine on one side. The rotor (6) of an electric machine is positioned on the outer surface (5) of the piston (2) and the stator (8) of the electric machine is positioned on the outer surface (7) of the cylinder (1). The stator (8) of the electric machine interacts electrically with the rotor (6) of said machine. The stator (8) of the electric machine is connected to a converter unit (9) in order to transmit electric energy bi-directionally. A spring force (F1) acting in the direction of the combustion chamber (4) is applied to a second end face (11) of the piston (2) by means of a spring device (12).

Description

description

Internal combustion engine with linear generator and Rückholfe ^¬ the

The present invention relates to a Verbrennungskraftma ^¬ machine,

wherein the internal combustion engine has a first cylinder,

wherein in the first cylinder, a first piston of the internal combustion engine is guided linearly, so that the first piston oscillates in the first cylinder between a first top dead center and a first bottom dead center,

- Wherein a first end face of the first piston a first combustion chamber of the internal combustion engine unilaterally be ^¬ limits.

Such internal combustion engines are well known. In particular, every common car engine works on this principle.

In a conventional internal combustion engine, the linear ^¬ movement of the piston is converted by means of a crankshaft in a rota ^¬ toric movement. However, it is also already known loading, the linear movement of the piston directly to the nut ^¬ zen, for example, for generating electrical energy. For example, reference is made to US Pat. No. 2,900,592 A or to the entry "free piston machine" in German Wikipedia (printed on 02 November 2012).

The use of a free-piston machine for generating electric ^¬ cal energy offers due to the fact that a Um ^¬ tion of the linear movement of the piston is omitted in a rotational movement, the potential of a simple structure and a good efficiency. This is against as disadvantages against ^¬ that the movement of the piston must be stabilized by means of a complex scheme and that the extremely high Accelerations of the piston can adversely affect the combustion process during the power stroke.

The object of the present invention is to develop an internal combustion engine of the type mentioned in the further that it is compact, works reli ^¬ permeable and with high efficiency and is easily controlled operable. The object is achieved by an internal combustion engine with the features of claim 1. Advantageous Ausgestaltun ^¬ gene of the internal combustion engine according to the invention are Ge ^¬ subject matter of the dependent claims 2 to 10. According to the invention an internal combustion engine of the type initially mentioned is a ^¬ configured by

that the rotor of a first electric machine is arranged on a lateral surface of the first piston,

that the stator of the first electric machine is arranged on a lateral surface of the first cylinder,

- That the stator of the first electric machine electrically interacts with the rotor of the first electric machine,

- That the stator of the first electric machine for bidirectional transmission of electrical energy is connected to a first inverter unit and

- That a second end face of the first piston is acted upon by ei ^¬ ner first spring means on the first combustion chamber to a first spring force.

Due to the arrangement of the rotor and the stator of the first electric machine directly on the lateral surfaces of the first piston and the first cylinder, the internal combustion engine can be made very compact. The bidirectional transmission of electrical energy between the stator of the first electric machine and the first converter unit enables in a simple manner a defined and optimized control of the movement of the first piston. On- Due to the loading of the second end face of the first piston with the first spring force load peaks of the electrical components of the internal combustion engine can be minimized.

In a preferred embodiment, the first spring means comprise a non-variable and / or a variable Fe ^¬ dereinrichtung. In the case of the presence of both the non-variable and the variable spring device, the two spring devices can alternatively be arranged next to one another or one behind the other.

In the simplest case, the internal combustion engine has no further cylinder except the first cylinder and no other piston except the first piston. In this case, the first piston operates as a rule in accordance with the two-stroke ^¬ principle.

In a preferred embodiment of the inventive combustion engine is provided,

- That in the first cylinder, a second piston of the internal combustion engine is guided linearly, so that the second piston oscillates in the first cylinder between a second top dead center and a second bottom dead center, - that a first end face of the second piston, the first combustion chamber of the internal combustion engine also one-sided limited,

that the rotor of a second electric machine is arranged on a lateral surface of the second piston,

that the stator of the second electric machine is arranged on the lateral surface of the first cylinder,

- That the stator of the second electric machine electrically interacts with the rotor of the second electric machine,

- That the stator of the second electric machine for bidirectional transmission of electrical energy is connected to a second inverter unit and - That a second end face of the second piston is acted upon by a second spring means on the first combustion chamber to a second spring force. This configuration offers several Variationsmöglichkei ^¬ th.

For example, in this configuration it is possible for the first spring device and the second spring device to have mutually different spring characteristics.

Alternatively, or in addition to use mutually different spring characteristics, it is possible that the first converter unit and the second converter unit are driven individually by one of the converter units common control device, so that the first piston is not moving pop u la ^¬ lig uniformly to the second flask. The movement of the two pistons must be similar. In particular, the movements must have the same fundamental frequency. However, they can have a phase offset, possibly time-variable, with respect to one another. Thus, for example, despite a constant stroke of both pistons, a variable displacement can be effected. Also, as an alternative or in addition to a variation of the displacement, harmonics of the movements of the two pistons may be different from each other.

The second spring device may comprise a non-variable and / or a variable spring device, analogous to the first spring device. Again, the two spring devices may alternatively be arranged side by side or one behind the other.

In the above-explained embodiment - including their possible variations - the first piston and the second piston usually also work according to the two-stroke principle. In a further preferred embodiment of the internal combustion engine according to the invention is provided

that the internal combustion engine has a second cylinder,

that in the second cylinder, a second piston of the internal combustion engine is linearly guided,

- That the second piston is mechanically coupled to the first piston, so that the first piston and the second piston always move uniformly,

- That a first end face of the second piston, a two ^¬ th combustion chamber of the internal combustion engine unilaterally be ^¬ limits,

- that the second electrical machine is disposed on a lateral surface of the second cylinder of the Sta ^¬ gate,

- That the stator of the second electric machine electrically cooperates with the rotor of the second electric machine, and

- That the stator of the second electric machine for bidirectional transmission of electrical energy is connected to a second inverter unit.

In this embodiment, the first piston and the second piston may alternatively operate according to the two-stroke principle or according to the four-stroke principle.

The above-described characteristics, features and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more clearly understood in connection with the following description of the embodiments, which will be described in more detail in conjunction with the drawings. 1 to 3 each show an internal combustion engine.

According to FIG. 1, an internal combustion engine has a first cylinder 1. In the first cylinder 1, a first piston ben 2 of the internal combustion engine linearly guided. The first piston 2 oscillates in the first cylinder 1 between a first top dead center OT1 and a first bottom dead center UT1. A first end face 3 of the first piston 2 bounds a first combustion chamber 4 of the internal combustion engine on one side. Incidentally, the first combustion chamber 4 of the internal combustion engine is limited by the first cylinder 1.

The first piston 2 has a cross section. The cross section can be circular. Alternatively, the cross section may for example be elliptical or oval. Other shapes are possible, for example, a polygonal cross-section, in particular with rounded corners. On a lateral surface 5 of the first piston 2, the rotor 6 of a first electric machine is arranged. The rotor 6 may include, for example, as shown in FIG 1 permanent magnets. In this case, the first electric machine is designed as a permanently excited synchronous machine. Alternatively, the rotor 6 could have a winding and the first electric machine thereby be configured as an electrically excited synchronous machine. Wiede ^¬ rum alternatively, the first electric machine could be formed ^¬ example as an asynchronous machine. Other configurations are possible.

On a lateral surface 7 of the first cylinder 1, the Sta ^¬ tor 8 of the first electric machine is arranged. The stator 8 interacts electrically with the rotor 6 of the first electric machine. At least in this area - ie in the area in which the stator 8 is arranged - the first cylinder 1 is preferably made of a non-magnetizable material, for example of aluminum or a sufficiently temperature-resistant plastic.

The stator 8 of the first electric machine is connected according to FIG. 1 to a first converter unit 9. Between the stator 8 of the first electric machine and the first Judge unit 9 can bidirectional electrical energy over ^¬ wear. The first electric machine can thus - depending on the control of the first inverter unit 9 - alternatively be operated as a generator or as a motor. As a result, in particular during the working stroke of the first piston 2, the movement of the first piston 2 can be specifically delayed and ^accelerated , thereby optimizing fuel consumption, emissions and / or power output of the internal combustion engine. The corresponding control of the first converter unit 9 is effected by a control device 10.

One of the first end face 3 opposite second end ^¬ surface 11 of the first piston 2 is acted upon by a first Fe ^¬ dereinrichtung 12 having a first spring force Fl. The first spring force Fl acts in such a way that the first piston 2 to the first combustion chamber 4 to be acted upon by the first spring force Fl, that the first piston 2, therefore, from ^¬ continuously from the bottom dead center UT1, is driven to the top dead center OT1 to. The first spring means 12 can DIE sem purpose, a non-variable spring device 13 umfas ^¬ sen, for example a coil spring 13. Alternatively, may comprise the first spring means 12 is a variable spring device 14, such as a gas spring 14. Again, alternatively, the first spring means 12 both non-variable as well as a variable spring means 13, 14 include. According to FIG 1, the non-variable Federein ^¬ direction 13 and the variable spring means 14 are arranged nebenei ^¬ Nander. Alternatively, they could be arranged one behind the other.

The configuration of the internal combustion engine of Figure 2 is based on the configuration of the internal combustion engine ge ^¬ Mäss Fig. 1 Below, therefore, only the additional embodiments are explained in detail.

According to FIG 2, in addition, a second piston 15 is linearly guided in the first cylinder 1. The second piston 15 oscillates - analogous to the first piston 2 - between a second upper Dead center OT2 and a second bottom dead center UT2. Also similarly to the first piston 2 defines a first end ^¬ surface 16 of the second piston 15, first the (common) combustion chamber 4 of the internal combustion engine of Figure 2 unilaterally. On a lateral surface 17 of the second piston 15, the rotor 18 of a second electric machine is arranged. The rotor 18 of the second electric machine may be formed in the same manner as or otherwise than the rotor 6 of the first electric machine. On the lateral surface 7 of the first cylinder 1, the stator 19 of the second electric machine is arranged wei ^¬ terhin. The stator 19 of the second electric machine interacts electrically with the rotor 18 of the second electric machine, analogous to the interaction of the stator 8 and the rotor 6 of the first electric machine. The ^stator 19 of the second electric machine is connected to a second converter unit 20. As with the first converter unit 9, electrical power can be transmitted bidirectionally between the stator 19 of the second electric machine and the second converter unit 20. Also, the second electric machine can thus - depending on the control of the second converter unit 20 - alternatively be operated as a generator or as a motor. The controller 10 also controls the second inverter unit 20. The first converter unit 9 and the second order ^¬ inverter unit 20 are thus driven by a common control device 10th Analogous to the first piston 2 and the second piston 15, a second end face 21 of the second piston 15 is acted upon by ei ^¬ ner second spring means 22 to the first combustion chamber 4 to a second spring force F2. The above ^¬ statements on the first spring means 12 are analogously applicable. In particular, the second spring device 22 may comprise a non-variable and / or a variable spring device 23, 24 analogous to the first spring device 12, for example a spiral spring 23 and / or a gas spring 24. Again, in the case of the presence of both Federein ^¬ directions 23, 24 alternatively, an arrangement of the non-variable and the variable spring means 23, 24 next to each other or in succession possible.

It is possible that the first spring device 12 and the second spring device 22 have the same spring characteristics. Alternatively, however, it is also possible for the first spring device 12 and the second spring device 22 to have mutually different spring characteristics. As a result, it is possible in particular to set different natural oscillation modes from one another.

Analogous to the use of the same spring characteristics, it is possible to control the first power converter unit 9 and the second Umrich ^¬ tereinheit 20 similarly. Alternatively, it is possible, depending ^¬ but that the first converter unit 9 and the two ^¬ te inverter unit are controlled individu ^¬ ell 20 of the control device 10th This can in particular be effected that the first piston 2 does not move completely uniformly to the second piston 15.

The design of the internal combustion engine according to FIG 3 is based on the design of Verbrennungskraftmaschi- ne according to FIG 1. Below, therefore, only the additional ^¬ union embodiments are explained in detail.

In the embodiment of the internal combustion engine according to FIG. 3, the internal combustion engine has a second cylinder 25. In the second cylinder 25, a second piston 26 of the internal combustion engine is guided linearly. In the Ver ^¬ combustion engine according to FIG 3, the second piston 26 is mechanically coupled via a coupling device K with the first piston 2. This ensures that the first piston 2 and the second piston 26 always move uniformly. The second piston 26 thus oscillates, as does the first piston 2, between the first top dead center OT1 and the first bottom dead center UT1. A first end face 27 of the second piston 26 defines a second combustion chamber 28 on one side. The other sides of the second combustion chamber 28 are ^¬ limited - analogous to the first combustion chamber 4 - from the second cylinder 25.

On a lateral surface 29 of the second piston 26 of the Läu ^¬ fer 30 a second electric machine is arranged. The rotor 30 of the second electric machine can - analogously to the rotor 18 of the second electric machine of FIG. 2 - be designed in the same way as or in another way as the rotor 6 of the first electric machine. On a lateral surface 31 of the second cylinder 25, the stator 32 of the second electric machine is arranged. Analogously to the second electric machine of FIG. 2, the stator 32 and the rotor 30 of the second electric machine interact electrically. Also, the stator 32 of the second electric machine is connected to a second inverter unit 33 analogously to the stator 19 of the second electric machine of FIG. 2 so that bidirectional electric power is provided between the stator 32 of the second electric machine of FIG. 3 and the second inverter unit 33 of FIG energy can be übertra ^¬ gen.

In the embodiment of the engine according to FIG 1 the first piston 2 operates generally in accordance with the two stroke principle ^¬. Likewise, in the embodiment of the internal combustion engine according to FIG. 2, the first piston 2 and the second piston 15 generally work according to the two-stroke principle. The arrows in the first combustion chamber 4 into and out of the first combustion chamber 4 are to indicate in Figures 1 and 2, the influx of fresh gas and the effluent of exhaust gas.

Also in the configuration of the internal combustion engine ge ^¬ Mäss FIG 3, the first piston 2 and the second piston 26 may operate according to the two-stroke principle. If, in the embodiment of the internal combustion engine according to FIG. 3, the working ^{shafts of} the first and second pistons 2, 26 alternate However, the internal combustion engine of FIG 3 alternatively work according to the four-stroke principle.

For proper operation of the internal combustion engine according to the invention, it is necessary to detect the position of the first piston 2 and optionally also the position of the second Kol ^¬ bens 15 and the direction of movement of the first piston 2 and optionally also of the second piston 15. This detection can be done for example by means of a magnetic or optical linear measuring system. Other detection ^¬ options are given.

The present invention has many advantages. Thus, in particular by the spring-assisted return of the first piston 2 and possibly also the second piston 15, 26 to the respective top dead center OT1, OT2 to the required peak power of the first electric machine and possibly also the second electric machine can be significantly reduced ^¬ , Nevertheless, an optimization of the combustion process can take place by appropriate activation of the first converter unit 9 and possibly also of the second converter unit 20, 33.

Although the invention in detail has been illustrated approximately example in more detail by the preferred execution and described, the invention is not ^¬ limited by the disclosed examples and other variations can be derived by those skilled thereof, without departing from the scope of the invention.

Claims

claims

1. internal combustion engine,

wherein the internal combustion engine has a first cylinder (1),

- wherein in the first cylinder (1) a first piston (2) of the internal combustion engine is guided linearly, so that the first piston (2) in the first cylinder (1) between a first top dead center (OT1) and a first bottom dead point (UT1) oscillates,

- wherein a first end face (3) of the first piston (2) ei ^¬ nen first combustion chamber (4) of the internal combustion engine limited on one side,

- Wherein on a lateral surface (5) of the first piston (2) of the rotor (6) of a first electric machine is arranged,

- Wherein on a lateral surface (7) of the first cylinder (1) of the stator (8) of the first electric machine is arranged,

- Wherein the stator (8) of the first electric machine electrically interacts with the rotor (6) of the first electric machine,

- Wherein the stator (8) of the first electric machine for bidirectional transmission of electrical energy to a first inverter unit (9) is connected and

- Wherein a second end face (11) of the first piston (2) by means of a first spring means (12) on the first combustion chamber (4) is acted upon by a first spring force (Fl).

2. Internal combustion engine according to claim 1, characterized in that the first Federeinrich ^¬ device (12) comprises a non-variable and / or a variable spring means (13,14).

3. Internal combustion engine according to claim 1 or 2, since ^{¬ characterized in} that the first piston (2) operates according to the two-stroke principle.

4. internal combustion engine according to claim 1 or 2, since ^{¬ characterized}

in that in the first cylinder (1) a second piston (15) of the internal combustion engine is guided linearly, so that the second piston (15) in the first cylinder (1) between a second top dead center (OT2) and a second bottom dead center ( UT2) oscillates,

- That a first end face (16) of the second piston (15) also limits the first combustion chamber (4) of the internal combustion engine,

- that on a lateral surface (17) of the second piston (15) of the rotor (18) is arranged a second electric machine,

- That on the lateral surface (7) of the first cylinder (1) of the stator (19) of the second electric machine is arranged,

- That the stator (19) of the second electric machine electrically cooperates with the rotor (18) of the second electric machine,

- That the stator (19) of the second electric machine for bidirectional transmission of electrical energy to a second inverter unit (20) is connected and

- That a second end face (21) of the second piston (15) by means of a second spring means (22) on the first combustion chamber (4) is acted upon by a second spring force (F2).

5. Internal combustion engine according to claim 4, characterized in that the first spring device (12) and the second spring device (22) have different spring characteristics from each other.

6. Internal combustion engine according to claim 4 or 5, since ^{¬ characterized in} that the first inverter unit (9) and the second converter unit (20) by a the inverter units (9,20) common control device (10) are individually controlled, so that the first piston (2) does not move completely uniformly to the second piston (15).

7. Internal combustion engine according to claim 4, 5 or 6, characterized in that the two ^¬ th spring means (22) comprises a non-variable and / or a variable spring means (23, 24).

8. Internal combustion engine according to one of claims 4 to 7, characterized in that the first piston (2) and the second piston (15) operate according to the second ^¬ act principle.

9. Internal combustion engine according to claim 1 or 2, d a c e c e s e c e n e,

- that the internal combustion engine has a second cylinder (25),

in that in the second cylinder (25) a second piston (26) of the internal combustion engine is guided linearly,

- That the second piston (26) is mechanically coupled to the first piston (2), so that the first piston (2) and the second piston (26) always move uniformly,

a first end face (27) of the second piston (26) unilaterally limits a second combustion chamber (28) of the internal combustion engine,

in that the rotor (30) of a second electric machine is arranged on a lateral surface (29) of the second piston (26),

in that the stator (32) of the second electrical machine is arranged on a lateral surface (31) of the second cylinder (25),

- That the stator (32) of the second electric machine with the rotor (30) of the second electric machine electrically cooperates and

- That the stator (32) of the second electric machine for bidirectional transmission of electrical energy to a second inverter unit (33) is connected.

10. Internal combustion engine according to claim 9, characterized in that the first piston (2) and the second piston (26) operate according to the two-stroke principle or according to the four-stroke principle.