DE19813992A1 - Free piston combustion engine with electrical energy delivery e.g. for hybrid automobile, heating plant or mobile current generator - Google Patents

Abstract

The engine has a non-metallic permanent magnet piston (1), linearly oscillated within an engine cylinder (9) via the combustion pressure and cooperating inductive coils (12), positioned around the cylinder, providing a voltage output. Piston position sensors (9), e.g. Hall elements, controlling electromagnetic, electro-hydraulic, or electro-pneumatic engine valves.

Description

State of the art

It is known from the patent classes F 01 B - 11/00; F 02 B - 71/00 that free piston engines usually with mechanical energy extraction through racks, Lever mechanisms etc. can be constructed.

The disadvantage of this solution is that these machines

• - require extensive sealing measures,
• - contain a lot of moving and lubricated parts and
• - Frictional losses occur at the power transmission devices.

Another variant is in DE-OS 30 29 287 (patent class F 02 B - 71/00) described.

The problems of this solution can be seen in the following points in particular:

• - sealing problems at the open ends of the cylinders,
• - poor exhaust behavior due to unburned oil in the exhaust caused by the applied mixture lubrication,
• - Flushing losses due to the working principle according to the two-stroke process in connection with external mixture formation.

In addition, machines are known which extract the energy from the system make electrical (inductive) way (cf. patent class H 02 K 7/18 in particular DE-OS 44 13 351 A1).

These represent a significant improvement over the machines with mechanical energy extraction. The solution described in DE-OS 44 13 351 A1 has the following problems:

• - Movable cable for power supply to the field coil (designated 1.2.1.1 there) required,  
• - insufficient lubrication and cooling,
• - sealing problems between the right and left motor-generator unit,
• - Versatility.

task

This invention aims to improve the overall efficiency of internal combustion engines improve the number of moving parts (crank mechanism etc.) and the friction losses minimize and save seals. Furthermore, a reduction in Wear and thus the maintenance effort can be achieved.

solution

According to the invention, these problems are solved in that a freely in one Permanent magnet piston arranged in a closed cylinder through the Combustion pressure is periodically moved back and forth and thereby one in the coil Voltage induced, which causes current to flow. This represents the useful energy of the machine described.

Description: Exemplary embodiment

The invention is explained in more detail below with the aid of a schematic drawing.

The free-piston internal combustion engine essentially consists of a cylinder ( 9 ) with flushing slots (inlet slots 7 , outlet slots 8 ) in which there is a freely movable piston (permanent magnet 1 , piston body 2 ) with a depression ( 3 ). A coil or a coil system ( 12 ) is arranged around the cylinder. The cylinder is closed at both ends by cylinder heads ( 5 ) with injection and ignition device ( 6 ). The lubrication channel ( 4 ) is formed by a taper in the central area of the piston. The lubricant inlet ( 10 ) is arranged in the cylinder wall. Furthermore, sensors ( 13 ) are arranged in the cylinder wall. The blowing device ( 11 ) communicates with the inlet slots. The machine also includes an electronic controller that is connected to the coil / coil system, the injector, the igniter and the injector, and the sensors.

For the functionality of the invention, the material properties of some parts of Meaning. In particular, these are the pistons that have a inside  Contains permanent magnets, the cylinder that does not have a magnetic flux disabling material.

Furthermore, the shapes of the piston crown and inner cylinder head limit must be like this be coordinated so that the volume converges towards zero when compressed, to prevent the piston from colliding with the cylinder head. It can be one enough small recess for the ignition electrodes in the piston crown, the no collision possible under normal operating conditions.

The mode of operation of the free-piston internal combustion engine (in the case of internal mixture formation, Coil system) is as follows:

Start phase

The piston is in any position. To start the machine, use the blowing device conveyed air into the cylinder. After that is in the coil system creates a magnetic traveling field that exerts a force on the piston and thus in it Movement in the direction of the cylinder head currently further away (in this example be it the cylinder head in subsystem A). Through this movement the air in the Cylinder compressed between this cylinder head and the piston. If the flushing slots are closed by the piston and sufficient compression is achieved through the injector fuel into the cylinder interior of subsystem A injected. The fuel-air mixture is then ignited by the Igniter. The combustion of the fuel-air mixture causes one Pressure increase in the cylinder interior of subsystem A. This pressure causes the Piston moved in the direction of the cylinder head of subsystem B. If successful Combustion follows normal operation from this point in time, otherwise the Starting process can be repeated.

Normal operation

While combustion takes place in subsystem A, fresh air in subsystem B promoted. After opening the flushing slots in subsystem A, the burned fuel Air mixture through the outlet slot into the exhaust system. At the same time, the Blower fresh air into the cylinder interior of subsystem A promoted. Due to the inertia of the piston, its movement continues, causing the air in  Subsystem B is compressed. When the flushing slots are closed by the piston and sufficient compression is achieved by the injector Fuel injected into the cylinder interior of subsystem B. Then the Ignition of the fuel-air mixture by the ignition device. The combustion of the The fuel-air mixture causes an increase in pressure in the interior of the cylinder Subsystem B. This pressure pushes the piston towards the cylinder head from Subsystem A moves. While combustion takes place in subsystem B, fresh air is in Subsystem A funded. After opening the flushing slots in subsystem B, the burned stream flows Fuel-air mixture through the outlet slot into the exhaust system. Because of the sluggishness the piston continues to move, which in turn causes the air in subsystem A is compressed. This process is repeated periodically.

The times for ignition and injection, as well as the amount of air delivered determined by the electronic control.

The continuous periodic piston movement causes an alternating voltage in the Coil / the coil system induced, which causes a current flow. This represents the Useful energy of the machine described.

Achieved advantages

The advantages of the invention compared to conventional internal combustion engines of the same power consist in:

• - improvement in overall efficiency,
• - reduction of exhaust emissions,
• - reduction in size and thus reduction in mass,
• - wide scalability of the size,
• - saving of sealing elements,
• - Freedom of spatial arrangement in a special application (no mechanical Power transmission),
• - simplification of warehousing, since only a few wear parts are contained,
• - Possibility of operating with different fuels, due to the possibility a variable compression ratio.

application areas

The described invention can be used, for example, as a hybrid drive for vehicles in Cogeneration plants and in mobile power generators are used.  

Reference list

0

Control unit

1

piston

2nd

Piston coating

3rd

Piston bowl

4th

Piston taper

5

Cylinder head

6

combined injection and ignition device

6.1

Igniter

6.2

Injector

7

Inlet duct

8th

Exhaust duct

9

cylinder

10th

Lubricant inflow

11

Blowing device

12th

Coils / coil system

13

Sensors

14

Iron sheet (electrical sheet)

15

Insulating layer

1

(Inner cylinder wall)

16

Insulating layer (between the iron sheets)

17th

Iron sheet separation (separation optionally offset and by

16

isolated)

18th

Injector

19th

check valve

20th

Inlet valve

21

Exhaust valve

22

Valve actuation (electromagnetic, electro-hydraulic or electro-pneumatic)

23

Fuel pump

24th

ignition coil

Claims (11)

1. Free-piston internal combustion engine with electrical energy extraction, characterized in that
that a non-metallic, permanently magnetic piston in a cylinder is caused to oscillate linearly by combustion pressure, and the energy is extracted from the system inductively by coils arranged around the cylinder,
that the rinsing process takes place via rinsing slots, and the machine works according to the two-stroke principle with reverse, cross or cross-flow rinsing,
that the fuel is introduced into the combustion chamber via an injection valve or a combination injection valve / spark plug,
that the moving parts are lubricated through one (or more) lubricant supply opening in the cylinder and lubrication groove (s) in the piston,
that position sensors (optical, inductive or based on Hall effect) are installed in the flushing channels, which tell the control system the current position of the piston (see Fig. 1). 2. Free-piston internal combustion engine with electrical energy decoupling according to claim 1, characterized in that two or more of the systems described above are arranged in parallel (both side by side as well as one behind the other) and firmly connected to one another, and execute the oscillating movement with a phase offset of 180 degrees in order to achieve this Keep the entire system as vibration-free as possible (see Fig. 2). 3. Free-piston internal combustion engine with electrical energy decoupling according to claim 1, characterized in that the purging process takes place via electromagnetically, electro-hydraulically or electro-pneumatically controlled valves (see Fig. 3). 4. Free-piston internal combustion engine with electrical energy extraction according to claim 1, characterized in that the cylinder of the machine consists of layered, electrically insulated iron sheets (electrical sheet) with an insulating layer on the cylinder inner wall to improve the magnetic flux and thus the efficiency (see Fig. 4). 5. Free-piston internal combustion engine with electrical energy extraction according to claim 1, characterized in that the fuel injection takes place indirectly (before the inflow slot) (see. Fig. 5). 6. Free-piston internal combustion engine with electrical energy extraction according to claim 1, characterized in that a check valve is arranged in front of the inlet slot, which prevents the exhaust gas from flowing out through the inlet slot (see Fig. 6). 7. Free-piston internal combustion engine with electrical energy extraction according to claim 3, characterized, that iron particles are arranged in the cylinder wall and thus an improvement in magnetic flux is reached. 8. Free-piston internal combustion engine with electrical energy extraction according to claim 1, characterized, that the cylinder inner wall and the piston surface with a sliding coating (e.g. ceramic) is provided to minimize the friction between these parts and avoid lubrication of the machine if possible. You can Lubrication channel and lubricant supply are not required. 9. Free-piston internal combustion engine with electrical energy extraction according to claim 1, characterized, that self-ignition of the fuel takes place with a correspondingly high compression (optional elimination of the ignition device). 10. Free-piston internal combustion engine with electrical energy extraction according to claim 1, characterized, that the detection of the piston position by measuring and evaluating the Currents / voltages in the coil system instead of through the sensors. 11. Free-piston internal combustion engine with electrical energy extraction according to claim 1, characterized in that the machine works according to the four-stroke principle. The valves required for this are operated hydraulically or electromagnetically. The piston movement is supported during the intake and compression cycle by current flow in the coils (see Fig. 3).