DE102010022614A1 - Hot air engine e.g. diesel engine, for motor vehicle, has expansion- and compressor pistons including main gasket and thermally disconnected, where compressor power is directly transferred to bearing and crankshaft over connecting rod - Google Patents

Abstract

The engine has a ceramic valve, and expansion- and compressor pistons (5a, 5b) including a main gasket (9) i.e. piston ring arrangement, where the pistons are thermally disconnected. Compressor power is directly transferred to a bearing and a crankshaft over a connecting rod. Compressor cylinders and a guide bush of an expansion cylinder form a unit for refrigeration. Stroke cross-sections are assigned to relatively small motor vehicle-series-crankshaft by a lateral separation of total stroke space. A pressurized air reservoir is separated from a heat exchanger section by a check valve.

Description

The application relates to a novel design of a hot air engine according to the Ericsson principle and a specially designed valve for the inlet-outlet control.

Summary of the present application:

• 1. die besondere Anordnung der Zylinder in einer gruppenweise Zusammenfassung für jeweils ein Pleuel und mit externer Kurbelwellen-Anordnung gesondert von den Zylindern. Durch die spezielle Konstruktion wird eine drastische Senkung bei der Anzahl der Einzelteile und Lager erreicht und mindert so den Herstellungs-Aufwand und die Reibung und damit auch die thermischen Verluste deutlich.
• 2. ein speziell konzipiertes, keramisches Drehschieber-Ventil zur zweckmässigen Steuerung des Fluid-Stromes diskontinuierlich nach Ein- und Auslass wechselnd mittels Kraft sparender, kontinuierlicher Drehbewegung angetrieben.
• 3. eine richtungs-abhängige Trennung des Komressor-Ausgangs von der Aufheiz-Strecke um den Gegendruck und damit die nötige Kompressorleistung zu reduzieren.
• 4. verbesserte Expansionsfähigkeit durch möglichst vollständiges Ausspülen der restlichen Heißluft mit frischer Druckluft am Ende jeder Expansionsphase.

Registration subject is

• 1. the special arrangement of the cylinders in a group summary for each conrod and with external crankshaft assembly separately from the cylinders. Due to the special design, a drastic reduction in the number of individual parts and bearings is achieved and thus significantly reduces the manufacturing effort and the friction and thus also the thermal losses.
• 2. a specially designed, ceramic rotary valve valve for convenient control of the fluid flow discontinuously driven after inlet and outlet alternately by means of power-saving, continuous rotational movement.
• 3. a direction-dependent separation of the Comressor output from the heating-up section to reduce the back pressure and thus the required compressor power.
• 4. Improved capacity for expansion by flushing out the remaining hot air as completely as possible with fresh compressed air at the end of each expansion phase.

General basics:

The Ericsson principle:

As cold as possible air is pre-compressed and then heated by means of heat exchangers, thereby a further pressure increase is achieved and subsequently available as working energy by means of expansion cylinders via connecting rods to a crankshaft.

The outstanding feature of the Ericsson machine is the continuous combustion of any fuel to generate the working heat outside the working cylinder without the intermediary of steam.

The introduction of the hot, unburned exhaust air of the engine into the burner as preheated combustion air and a good thermal utilization allows.

The compressor volume is usually smaller than the expander volume.

Advantages / disadvantages of the Ericson engine

The overall construction has a relatively large footprint, but the engine is lightweight and low in material steam is not generated or used here and it eliminates all the associated risks and expenses. Special buildings are not necessary, an enclosure with container is sufficient.

As a result, the investment compared to conventional heating power plants are significantly lower.

The heat energy from the fuel is not cooled away, only the compression heat of the compressors and the frictional heat of the piston seals are to be cooled.

Thus, the engine does not have the usual waste heat losses, it works ideally adiabatic. By external combustion and operation of the engine with filtered fresh air, the engine operates regardless of the type of fuel, as long as the energy supply can be ensured.

Therefore, here low-grade fuels can be used and the operating costs are therefore much lower than when using high quality fuels such. B. in CHP.

Disadvantages are the large quantities which are required for low-grade fuels - especially for mobile operation - on the other hand, these fuel quantities are sufficient and unused in several economic areas - z. B. in agricultural operations and waste disposal.

The required triple heating capacity of the combustion systems makes for large electrical power -. For example, at 500 kWe with 1 500 kW burner - the use of two or four burners makes sense. The burners and the fuel supply are decisive for the space requirement.

Commitment:

The system is hardly suitable for mobile use. However, a use as a ship propulsion was realized by Ericsson.

The use is to be selected in the stationary area - preferably in the generation of electricity using cheap fuels (eg agricultural waste, flammable waste or extra biomass)

In contrast to internal combustion engines such as gasoline / diesel or gas engine, the hot-air engine of course has no problems with supplies such as biodiesel, vegetable oil, bio / landfill gas or alcohol. In individual cases, the burner must be adjusted as much as possible

Only with an Ericsson or Stirling engine, it is possible to use all fuels for power generation in areas below 5 megawatts down to 10 kW compared to the current cogeneration plants. Opposite the closed Stirling engine, the heat energy is passed on to the burner as a hot combustion supply air with the open Ericsson engine, keeping the system cool enough to cool off the heat, and several cylinders can be supplied with one heat source With containers and no steam line is used, these systems can usually be realized with investments as low as otherwise typical for CHP - - but without their high operating costs and mechanical vulnerability

This creates the opportunity for individual smaller economic units such as villages or farms to achieve self-sufficient power generation with the available energy sources in relation to the calorific value four times more efficient than with biogas plants and at a fraction of their costs and space requirements.

Materials that could previously only be used for heating purposes, can now be converted into electricity with such systems.

• • Motor-Probleme mit den Bio-Treibstoffen Pflanzenöl, Biodiesel, Biogas, und Schmierstoff-Unverträglichkeit
• • Einschränkungen bei den Brennmaterialien: außer für Pflanzenöl und Bio-Diesel/-Gas ist sonst nur noch für holzähnliche – Materialen genugend ausgereifte Technik verfügbar.
• • Geringe Ausnutzung der Biomasse: außer bei Holz werden nur geringe Mengen der Pflanzen-Energie tatsächlich fur die Stromerzeugung nutzbar – Biogasanlagen z. B. setzen ca. drei Viertel des Kohlenstoffes aus Biomassen energetisch ungenutzt als CO2 wahrend der Fermentierung frei; Bei Ölpflanzen wird nur der geringe Öl-Anteil – meist weniger als 10% der Pflanzenmasse – genutzt.

All the problems that occur with conventional biomass power generation

• • Engine problems with the bio-fuels vegetable oil, biodiesel, biogas, and lubricant incompatibility
• • Restrictions on fuel: except for vegetable oil and bio-diesel / gas, only technically mature technology is available for wood-like materials.
• • Low utilization of biomass: except for wood, only small amounts of plant energy can actually be used for power generation - biogas plants, for example. For example, about three-quarters of the carbon from biomass releases energy unused as CO2 during fermentation; In oil plants, only the low oil content - usually less than 10% of the plant mass - used.

Prior art and the innovations of the present application

In contrast to the newest found U.S. Patent # 7,028,476 from 2006, in which for this type of engine each expansion cylinder and each compressor cylinder claims its own connecting rod and a place on the crankshaft and separate piston seals as well as separate cooling zones, in the present application delimiting it two times two in opposite directions working cylinders - that is four - on a common connecting rod, and the associated compressors form a unit with one cylinder.

A compressor is thus operated in direct connection with the associated working piston and uses the same piston seal. This avoids that the power for the compressor drive from the working piston is passed through the crankshaft.

Depending on an expander and a compressor use the same piston seal. In such an embodiment, the number of required parts and friction losses are significantly lower.

The sum of the synchronized cross sections is much larger than in a series, V or Boxer arrangement of cylinders and the ratio of the summed cylinder diameter to the stroke length is hydraulically much better.

Because the compressor and expander are combined here, common cooling can be used for both. The thermal separation allows the cooling of the compressor and piston seal without the heat energy of the hot air is significantly reduced.

The above US application uses two camshafts and two poppet valves per working cylinder. This type of control is power-consuming and requires mandatory lubrication. Even if the controller u. U. can be performed with only one camshaft, this construction is not only power-consuming but also expensive to manufacture.

In addition, the desired thermal insulation in the expansion area is reduced by the poppet valves.

Second, the present application is distinguished by the use of a novel ceramic Dehschieber valve with energy-saving, continuous drive for the proper control of inlet / outlet flow to avoid these disadvantages.

It is z. B. one side of the rotary valve wing specially designed for the below explained flushing of the heating-up route by overflow.

A third distinction from the above US application is the separation of the compressor reservoir from the heat exchanger area by a check valve to avoid that the pressure increase in the heating of the pre-compressed air to the compressor and thus greater performance for the Compression requires. At the Ericsson logon, this separation was through the charge valve because the compressed air was not heated directly in the cylinder until the charge was completed.

Fourth, the present application is distinguished from the above US application in that here the heat exchanger area is rinsed as far as possible with cool, dense compressed air, so as to ensure the highest possible expansion capability of the air to be heated. This is due to a special design above ceramic valve and / or achieved by an additional short-term bypass venting at the end of the expansion process.

The heating of the fresh compressed air then takes place during the emptying phase.

In order to ensure the longest possible heat-up time, cylinder groups that are connected in series have a separate heat exchanger section. Separate compressed air tanks, however, are only necessary if the mechanical design or a cooled design makes this desirable.

The construction after U.S. Patent # 7,028,476 would z. B. For four expansion cylinders eight connecting rods and crankshaft bolts accordingly need: 4 for the expander and 4 for the compressors. In the proposed arrangement only a connecting rod and a crankshaft space is required. In addition, each crankshaft bolt receives two drive pulses per revolution of the two-stroke counter-rotating double piston.

Another advantage is that because of the distributed cylinder corresponding to the rather continuous load small and light crankshafts from normal car series production can be used and still output power of z. B. 500 kW can be achieved.
(eg with shafts for originally 200 kW drive power)

Wear and friction losses are further reduced in a timely manner by suitable coatings at the critical points. (eg DLC)

Because each group pulls during half a turn and pushes during the other half turn and the groups are arranged gegüber, the crankshaft bearings are laterally evenly loaded over a conventional structure in which always the same side is loaded This one-sided wear of the bearings is avoided and increases the life.

In the following, the individual components are explained in more detail on the basis of principle drawings on the boards 1-5 in the pictures 1-14.

Double piston unit:

The double-piston unit is basically designed like a free-flight piston and consists of the parts shown in Fig. 1:

LIST OF REFERENCE NUMBERS

1

Rotary valve for inlet / outlet of the working fluid

2

Cylinder head; Heat-insulated

3

Cylinder top; Heat-insulated

4

Cylinder lower part and compressor cylinder; cooled (air or water)

5

Combination piston, split and thermally separated for

5a

Expansion piston with the guide seal 9 , Heat-insulated

5b

Compression piston with the main seal (eg piston rings)

6

Reduction sleeve for compressor displacement

7

Compressor inlet

8th

Compressor outlet

9

Guide seal preferably non-contact

10

piston rod

Two double-piston units and the associated compressors are combined into a cylinder group and connected by means of a bridge.

At the bridge, the connecting rod-head joint is arranged in the manner of a piston pin bearing.

The piston rings can run far back in the cooled area due to the rigid piston / piston rod arrangement. As a result, the choice for slip coating is greater.

This can also allow the use of piston rings made of Teflon-carbon mixture.

The following additional components shown in Figure 2 are required for the function:
(Parts with numbers 1 - 10 as in picture 1)

LIST OF REFERENCE NUMBERS

11

bridge

12

Connecting rod bearing

13

pleuel

14

Crankshaft with crank-bolt bearings

15

Crankshaft cage with the crankshaft bearings

Caution - not shown because of the clarity:
The two opposite combination cylinders are fixed against each other.

The schematic, spatial view is shown in Figure 3.

It is a sixteen unit on a four-stage crankshaft to see.

The fixation of the double-piston units against each other is shown here as a continuous cylinder tube.

Ceramic rotary valve control valve

For the adapted control at a relatively high speed of 1,000-2,000 rpm, a special expansion cylinder rotary valve has been developed.

• • möglichst lange Öffnungszeiten während der Kolben-Bewegung in einer Richtung
• • Vermeidung der Nockenwelle wegen der verteilten Zylinder und um Kraft zu sparen
• • Je Zylinder nur eine gemeinsame Steuereinheit für Einlass und Auslass
• • Vermeidung von Teller-Ventilen und eine große Durchlass-Kapazität
• • Lange Öffnungs- und kurze Schließ-Intervall-Steuerung bei kontinuierlicher Drehung
• • Das Ventil soll wegen der Wärmedämmung aus kermischen Werkstoffen realisiert werden
• • Zu- und Abgänge sollen im Winkelbereich von 180° in 90°-Schritten frei wählbar sein.

Objective was

• • the longest possible opening times during piston movement in one direction
• • Avoiding the camshaft because of the distributed cylinders and to save power
• • Only one common inlet and outlet control unit per cylinder
• • Avoidance of disc valves and a large passage capacity
• • Long opening and short closing interval control with continuous rotation
• • Due to the thermal insulation, the valve should be made of kermic materials
• • Inlets and outlets should be freely selectable in the angular range of 180 ° in 90 ° increments.

The solution to the problem meets the three-way rotary valve shown in Figure 4 below, which - except the axis - is consistently made of ceramic material and thus ensures the thermal insulation and wear resistance.

The design allows the connections to be placed the same or alternately as required. The assignment for loading and clearing is defined by the angular offset of the segment discs (see Figure 6).

After assignment of the segment discs to the main body according to the desired arrangement of the connections, the individual parts of the rotary valve are connected by means of a high-temperature ceramic adhesive and then form a form-locking driven unit from the axis.

The axis can then no longer be removed from the rotary valve.

The valve is seated with the lower opening (I / O) on the respective expansion cylinder cover. The charging and emptying connections on the housing jacket are offset by 90 ° from the lower opening.

Figure 6 shows the individual parts:
A main turning body ( 1 ) is positively locked by an axis ( 2 ) and opens passage from the lower opening (I / O in Figure 4) of the valve shell for the half rotations in two different directions - depending on the direction of movement of the piston to the inlet or outlet for loading or broaching.

However, the double-angle longitudinal section of this main body does not provide any circumferential guidance and sliding bearing. In addition, the axle on the side covers obstructs the placement of large-volume connection openings.

These must therefore be arranged on the circumference of the main body of the valve. Since there is no room for the connections in the direction of the cylinder head, they must be offset against the I / O opening at a 90 ° angle. This will cause the segment discs ( 3 ) required to achieve a passage for turning angle greater than 90 °.

One segment disc each ( 3 ) opens and closes the side openings synchronously with the foot opening in the required directions. The segment discs are also positively driven.

The guide disc arranged on both sides ( 4 ) ensures a continuous guidance and bearing for the rotation in addition to the sealing rings (Simmerrings) of the axle in the two side covers of the valve (Figure 5).

The side covers also serve the cohesion and assembly of the valve on the cylinder cover.

Explanation of the control of the expansion cylinders:

Since the cylinders operate in two-stroke cycle, the valves rotate synchronously with the crankshaft, driven by conventional devices such. B. timing belt.

With four crank pins, two groups of double cylinder units are arranged on each side of the crank shaft.

In the process, the valves are in axial alignment for every two expansion cylinders.

For the inner expansion cylinders are four times two valves in flight.

The in-flight valves are driven by means of a common pulley on a durchgerendangetribene coupled at the required angle axis.

For the inner cylinders, the valves preferably form a closed row and share the intermediate side plates.

In order to give the valves possibly pre- or caster over the crankshaft, the two tension rollers are directly adjustable next to the crankshaft pulley.

It makes sense to drive groups with belts (chains). In the illustration, two belts run as output to the groups of a side via the crankshaft. See picture 8.

For more crank-seats, the principle is similar - z. B. eight-cylinder shaft.

Belt guide with position to cylinders and valves as well as crankshaft see picture 9.

flush

Figure 10 shows schematically the flow path with the new valve with overflow vane. (Note: the two segment discs are offset by 90 ° from the middle part (see Figure 7).

Thus, the respective paths are put through during a rotation angle of about 160 ° real - not as in the picture for less than 90 °.)

Procedure As soon as the shutter side of the rotary valve passes through the (I / O) opening, in synchrony with which the inlet segment disc releases the inlet and the piston has passed top dead center (TDC), charging begins. (Picture 10.1)

The emptying path is blocked during this phase by the outlet segment disc and the vanes of the rotary valve. Hot compressed air exerts force on the expander piston until it reaches its end position at bottom dead center (UT) of the crankshaft.

Now, the flushing blade of the rotary valve has reached the (I / O) opening and, despite the full cylinder, allows the hot residual air to escape via the exhaust air path (towards the burner). Thus, the purpose is achieved as completely as possible to renew the air in the heat exchanger to ensure maximum expansion by influx of cool and dense air. (Picture 10.2)

A bypass valve can assist or replace this process. The bypass valve should be designed in such a way that it only opens briefly for flushing briefly during the UT.

When the UT is exceeded, the emptying process begins. The piston pushes the expanded hot air out of the cylinder in the direction of the burner until the TDC. (Picture 10.3)

• – Mit Überschreiten des OT beginnt der Ablauf von neuem. (Bild 10.4)

The charging path is blocked during emptying by the segment disc and the blades of the rotary valve and can be thermally charged undisturbed.

• - If the TDC is exceeded, the process starts again. (Picture 10.4)

Figure 11 shows schematically the flow path with the new valve and a bypass valve.

Figure 12 shows for comparison the flow scheme of said US Patent

Figure 13 shows the flow scheme according to the present application

Figure 14 shows the flow diagram for the new process and flow path of the run with the assignment to the cylinder groups

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 7028476 [0021, 0034]

Claims (9)

An expansion piston and a compressor piston each form a unit and have only one common main seal (piston ring arrangement), but are thermally separated. As a result, the associated friction is almost halved. Loss and wear are reduced. Manufacturing effort for pistons and seals are reduced. By the combined piston, the compressor power is transmitted directly and not as in the U.S. Patent # 7,028,476 over the connecting rods, their bearings and the crankshaft. The losses over the connecting rod and shaft bearings and the corresponding wear account for these forces. Since the compressor cylinder and guide bushing of the expander cylinder form a unit, only one cooling is necessary and thus reduces the thermal losses. Manufacturing overhead for cooling and cylinder bushings is lowered. Due to the lateral offset and gegwärtliegende division of the total stroke space can be assigned to a relatively small series car crankshaft a multiple of displacement - cross-section than in engines commonly used arrangements. Manufacturing effort is reduced by avoiding expensive special waves The group arrangement of cylinders and compressors reduces the number of connecting rods, connecting rod head and foot bearings and the number of crank pin and shaft bearings by more than 85%. The manufacturing effort is reduced. The use of the new ceramic valve brings improved thermal insulation and reduces power consumption. The manufacturing effort is reduced compared to plate valves. Forward or caster of the valves relative to the crankshaft is achieved in a simple manner by adjusting the tension rollers. The additional purge function of the valve (and / or a bypass valve) enhances the expansion capability. The efficiency is increased The power consumed by the compressor is reduced by separating the compressed air resovier from the heat exchanger section. The separation is done by a check valve. The efficiency is increased

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