WO2002070878A1

WO2002070878A1 - A rotary engine

Info

Publication number: WO2002070878A1
Application number: PCT/SE2002/000402
Authority: WO
Inventors: Kaare B. Vatne
Original assignee: Abiti Ab
Priority date: 2001-03-07
Filing date: 2002-03-07
Publication date: 2002-09-12
Also published as: JP2004527682A; SE0100744D0; WO2002070878A8; SE0100744L; EP1399658A1

Abstract

A combustion engine (10) comprises compression and drive units (30, 40) with co-rotating elements (30a, 30b, 40a, 40b) and at lease one external combustion chamber (20) influid communication with the units. Each of theunites (30, 40) has two co-operating lobes (30a, 30b, 40a, 40b) rotatable ina housing on shafts (50, 60, 70 ,80) with opposite rotational directiosn, the respective lobe shafts of theunits being in connection wiht each other. the lobes are arranged to control the inlet (20a) and outlet (20b) to an dfor the at least one combustion chamber and the atmosphere. The outlet (20b) of the at least one combustion chamber (20) extends radially towards its assocated lobe (40a, 40b) or the drive unit (40).

Description

A ROTARY ENGINE

Field of the Invention

The present invention relates to a combustion engine comprising compression and drive units with co-rotating elements and at least one external combustion chamber in fluid communication with the units.

Prior Art

The most common engines or plants using gas combustion are divided into two types, of which the first type uses an external combustion chamber and the second type uses an internal combustion chamber.

The most common engines using gas combustion in an external combustion chamber are gas turbines. Gas turbines are widely used in different applications, e g they are used for propulsion in aircraft, submarines, ships, and cars, and also for power and/or heat generation in power plants .

The most common combustion engines with an internal combustion chamber are Otto and Diesel engines. They are also used for propulsion in aircraft, submarines, ships, and cars, and for power and/or heat generation in power plants .

One difference between the two above-mentioned types of engines is that in gas turbines the parts transferring the energy from the gas, the turbines, rotate as well as the drive shaft, thereby eliminating the need for a connecting rod and a crankshaft, as in a Otto or Diesel engine. Moreover, the torque arm, i e each turbine blade, has the same length during an entire revolution of the drive shaft . In Otto and Diesel engines on the other hand the parts transferring the energy from the gas, the pistons, move back and forth in an essentially linear motion. The essentially linear motion is perpendicular to the longitudinal axis of the crankshaft, i e the axis of rotation for the crankshaft. Therefore, the length of the torque arm for transferring the essentially linear motion from each piston by way of a connecting rod and a crank shaft into rotating motion for the drive shaft changes at each point of the essentially linear movement of the piston.

Another fairly common combustion engine with an internal combustion chamber is a Wankel engine or a rotary engine. Here, the part transferring the energy from the gas, the piston, rotates inside the appropriately shaped combustion chamber. The piston is attached to a crankshaft by way of an eccentric and a gear wheel for transferring the energy of the gas into rotation of the drive shaft around its longitudinal axis. The energy from the gas affects the piston in both the radial and tangential direction but the piston does not rotate in a wholly circular or linear path around the longitudinal axis of the crankshaft due to the eccentric and the gear wheel. Here, the length of the torque arm for the piston also changes somewhat at each point of the movement during the rotation of the crank and drive shaft .

The main difference between the Wankel engine and a gas turbine is essentially the same as for the Otto and Diesel engine.

One difference between the Wankel engine and the Otto or Diesel engine is that there is no wholly linear movement for the piston in the radial direction of the crankshaft in the Wankel engine, whereby the changes in mass forces are smaller generating less engine vibrations. Another difference is that the length of the torque arm for the Wankel piston generally does not change as much as for the Otto or Diesel engine giving a less varying torque on the crankshaft . Summary of the Invention

The main objects of the present invention are to enhance the durability of a rotary engine by making the length of the torque arm for transferring the power from the gas combustion into rotational motion of the crankshaft constant, reduce the vibrations of the rotary engine by simplifying the balancing/counterweighting of the rotating parts, and generally combine the advantages of an engine having an external combustion chamber with the advantages of an engine having an internal combustion chamber. These objects are achieved by a rotary engine according to the invention. A combustion engine in the form of a rotary engine according to the invention comprises - like a turbine - compression and drive units with co- rotating elements, and at least one external combustion chamber in fluid communication with the units. Each of the units has two co-operating lobes rotatable in a housing on shafts with opposite rotational directions, the respective lobe shafts of the units being in connection with each other. Furthermore, the lobes are arranged to control the inlet and outlet to and from the at least one combustion chamber and the atmosphere .

Brief Description of the Drawings The present invention will now be described in further detail, reference being made to the accompanying drawings, in which:

FIG 1 is a view in section of a first embodiment of an engine according to the invention, FIG 2 is a longitudinal view in section of the engine in FIG 1,

FIG 3 is a longitudinal top view in section of the engine in FIG 1 with its housing omitted,

FIG 3A is a side view of the engine in FIG 3, FIG 4 is a top view in section of a modified upper part of the engine in FIG 1,

FIG 5 is a view in section of a second embodiment of the engine according to the invention, FIG 6 is a longitudinal view in section of the engine in FIG 5,

FIG 7, in a sectional view, illustrates one phase in a drive cycle of the engine in FIG 1,

FIG 8 is a view in section of another phase in the drive cycle of the engine in FIG 1,

FIG 9 is a view in section of yet another phase in the drive cycle of the engine in FIG 1, and

FIG 10 is a view in section of an additional phase in the drive cycle of the engine in FIG 1, FIG 11 is a view in section of one phase in a compressor cycle of the engine in FIG 1,

FIG 12 is a view in section of another phase in the compressor cycle of the engine in FIG 1,

FIG 13 is a view in section of yet another phase in the compressor cycle of the engine in FIG 1 , and

FIG 14 is a view in section of an additional phase in the compressor cycle of the engine in FIG 1.

Detailed Description of the Invention FIG 1 shows a front view in section of a first embodiment of a rotary engine 10 with a pair of external combustion chambers 20. The rotary engine is enclosed by a housing 11, which comprises two end parts 12 and 13, two separating parts 14 and 15, and one middle part 16, this is more clearly shown in FIG 2. The rotary engine comprises at least two units 30 and 40, each unit comprising a pair of rotating parts, the units being displaced in relation to each other in the longitudinal direction of the rotary engine. In this embodiment, the rotating parts in each unit have the same form and size and rotate in the same plane, each rotating part forms a swept circular volume during one revolution. The middle part 16 encloses the main part of the rotating parts, wherein the two separating parts 14 and 15 of the middle part 16 encloses the remaining part of the rotating parts and separates the middle part 16 from the end parts 12 and 13. The pair of external combustion chambers 20 is placed in the middle part. The first unit 30, in the following referred to as a compressor unit and having a pair of compressor lobes 30a and 30b, works as a compressor for compressing air to be used in a gas combustion. The second unit 40, in the following referred to as a drive unit and having a pair of drive lobes 40a and 40b, is driven by a gas expansion in the gas cycle after the gas combustion in the combustion chambers 20. Each of the two units is enclosed by a cavity formed by the middle part 16 and one of the separating parts 14 or 15. The right side of the middle part 16 and the separating part 15 encloses the compressor unit 30. The left side of the middle part 16 and the separating part 14 encloses the drive unit 40. The rotary engine 10, i e the housing 11 and its associated parts 12, 13, 14, 15 and 16 are connected by, e g screws, bolts, welding, shrink-fit or any other means known to a person skilled in the art . The housing has an essentially oblong shape corresponding to each unit 30 and 40 being placed side-by-side, as shown in FIG 1. In FIG 2, each of the two external combustion chambers 20 has an inlet 20a, which is in communication with the upper part of the associated compressor lobe 30a or 30b of the compressor unit 30. Each of the two external combustion chambers 20 also has an outlet 20b, which is in communication with the upper part of the associated drive lobe 40a or 40b of the drive unit 40. The outlets of the combustion chambers are shaped as expansion nozzles and have the same discharge direction as the direction of movement for the lobes, i e the discharge of gas occurs in the same direction as the direction of rotation for each lobe. This means that at least one outlet 20b of the combustion chambers 20, or, preferably, each outlet extends and discharges the gas in the radial direction of the rotational axes of the rotary engine 10. Furthermore, one or more outlets 20b of the combustion chambers 20 discharging the gas radially may be used together with at least one outlet discharging the gas tangentially in relation to the periphery of the circle created by the rotation for each lobe 30a, 30b, 40a and 40b. The construction of the rotary engine will only be described with reference to Figs. 1-6, whereas the function of the rotary engine will be described with special reference to Figs. 7-14. In FIG 1 the two units 30 and 40 are in communication with each other through the external combustion chambers 20, which preferably are placed above the units and extend in the axial/longitudinal direction of the rotary engine 10. This is more clearly shown in FIG 2. The external combustion chambers may also be placed below the two units 30 and 40 by rotating/turning the engine upside down, i e 180° in relation to the position in FIG 2.

In this first embodiment of the rotary engine 10, shown in Figs. 1-3, the compressor lobes 30a and 30b of the compressor unit 30 are attached to rotating shafts. The first compressor lobe 30a is attached to a first rotating hollow shaft 50, and the second compressor lobe 30b is attached to a second rotating hollow shaft 60. The drive lobes 40a and 40b of the drive unit 40 are attached to solid rotating shafts, whose centre axes coincide with the centre axes of the hollow shafts 50, 60 of the compressor unit 30. The first drive lobe 40a is attached to a third rotating shaft 70, and the second drive lobe 40b is attached to a fourth rotating shaft 80. The third and fourth solid rotating shafts 70 and 80 have an outer to

K \ o o O l

Ω CQ Φ- 3 0J ft φ. μ- CD o 0J 0 tf O w Ω øJ ^ P- CD 0J

Ω rt •» ø H- 0J CQ 0⁾

0 Φ. CQ O 0J 1=1

0J Hi o O CQ P

H tr 0J rt tr

- Ω t CD φ.

CD 0J 0" CD 3 X o i-r- H J 13 tr

0J CD CD 0 H- ; 0⁾ 3 CD CQ Hi ø 0 Hi

CD 3 13 rt PJ CQ 0 μ- CD rt 0J μ- ii

CQ 1 Ω ø^J tr CQ 0

H- Ω rt CD CD O ø CD

3 H- H- 0

H- ii <! Ω 13 tr 0J l-¹ Ω CD 0 0 CD H tr

0J 0 I-¹ ii ør ii I-¹ 13 rr

^ 13 CD μ-

0J ii CQ ø rt ii CD PJ CD LQ

0 ør CQ 0J Ω x

0J CQ 0 CD tr p. øJ 13 <! 0 Pi P. PJ μ- ϋ CD ϋ ø CQ i-T CD 0 J CQ Ω

0J i- CD SD H tr rt tr

CD CQ 0 0 0⁾

Ml H CQ p. Ω <! 13 ii

1 0J CD t CD 0 CQ

3 tr 0 J 0J i CD

0 rr ϋ 0 rt rt

0 H- H-

^ 0 ø^J CQ 0

HI 0⁾ <! CD CD l-h

CD 0⁾

CD CQ CD ø CD

H CQ ^ ø P. X ø^J CQ 0 LQ \ tr

Φ CD ft tr H- 0 0⁾

0 -r CD 0 i rt CD CQ CD CQ

0 μ- Ω rt tr 0⁾ CD ) μ- tr

CD I-¹ 0J O ø ØJ CQ

CQ 3 0⁾ ø ØJ

^ CD ^ rt ø CQ

H- ø^J CD CD

0 tr Ω u CD CO

0⁾ ii o CQ

CD 0 tr CQ J

0J Hi LQ øJ M l-h a 1 CQ J 3 O rt tr 1 ø CD O CD

P. PJ ii

pair or unit 30 or 40 rotate in opposite directions in circles around their associated, rotating shafts 50, 60, 70 or 80. These circles or swept volumes are in the same plane for each pair of lobes and formed essentially "side by side", similar to the muzzles of a side-by-side shotgun or a pair of binoculars, but overlap each other somewhat in the middle. The overlapping means that each pair of lobes 30a and 30b, and 40a and 40b interact similar to gear wheels with only two teeth. The tooth function is created by two surfaces, one involute-shaped surface at each end of the half-moon, i e surfaces 30' and 30" on each compressor lobe and surfaces 40' and 40" on each drive lobe. Each surface has the form of a gear-wheel tooth cut in half in the radial direction of the gear wheel. Moreover, the half- circular form for each lobe gives a valve function, i e the lobes alternately close and open the external common combustion chamber 20, the intake channels 90a and 90b, and the exhaust channels 100a and 100b during rotation. However, the units 30 and 40 may at some point or points of time during the rotation of the lobes be in communication with each other, i e the external combustion chamber may not be completely closed at one unit when the other unit is open or opens. This means that a small overlapping exists shortly and an exchange of gases between the units occurs at these points during the emptying of the exhaust gases, but this occurs only a short while during the rotation and has no significant effect on the efficiency of the rotary engine 10.

The compressor and drive lobes 30a, 30b and 40a, 40b have the same half-circular cross-section but may have different cross-sections, heights or thicknesses. The compressor and drive lobes may have different cross- sections; for example each of the compressor lobes could have a cross-section that is larger or smaller than the cross-section for the associated drive lobe or vice versa. ) w ) t > * o o KM o

0 μ- P. P. rt Ω o PJ O £ rt μ- 0 Ω 0 13 CQ 13 0 rt 13 rt rt ØJ Ω 3 HT LQ LQ Ω rt H

0 ø μ- >i ø 0 0 rt ø 0 tr ii 0 Hi 0J rt øJ ϋ € ØJ πr HT O HT 0 o Φ φ μ- 0 0 Hi rt Ω 3 μ- H 3 rt 3 rt ø Φ Φ 3 μ- øJ μ- 0 μ- μ- μ- tr 0 Φ ii 0J <!

LT 3 ii

H ϋ φ <! tr 0 μ- 13 rt ii LQ ϋ 0J ii Ω Ω Φ 0 H r ^r μ- ϋ μ- 13 tr rt φ Φ ø Φ μ- ø φ CQ Φ Pi h-¹ rt ø ϋ HT Φ CQ 0 13 CQ X ^ LQ φ μ- Ω ø ϋ 0 tr rt ØJ CQ ø CQ rt 13 rt ØJ tr rt φ Φ 0 . ^ ø ø ø 13 tr 0 ØJ ØJ rt LQ Φ

CQ CQ μ- 0 φ rt CQ HT CQ HT CQ Φ 0J CQ Hi rt μ- 0 Φ φ øJ rr ^• : φ CQ Φ CQ Ω μ- 0 ø μ- Φ 0J rt I CQ Hi ø en O ii Hi CQ CQ μ- tr Pi Φ rt CQ tr Ω μ> ø ø μ- μ- 3 0 μ- ii 0 <! IQ φ O μ- H ø rt CQ CQ CQ i Φ rt ØJ rt rt HT O 0J 0 o LQ CQ rr CQ ø 0 ø Φ Hi Φ Ω φ M ϋ o tr Ω tr Ω φ ~ CQ tr 2 0 HT Φ i H 3 o O Ω 13 CQ tr μ- tr Φ 0 0 CQ Φ μ- HT 0 LQ 13

0J CQ μ- Φ. 13 rt Ω Ω øJ rt μ- 3 0 0 rt Φ ø H Hi 3 0 0 rt Φ rt Hi CQ Φ i μ- ø o 0 μ- HT 0 CQ tr rt 13 0 ϋ 0 CQ φ ØJ 13 ϋ £, 0 Ω tr tr 0 0⁾ 0 ii Φ

ØJ N CQ I 0J 3 φ CQ ϋ i rt tr Ω ø Ω H 3 tr LQ ii μ- ii 3 tr CQ

0 Φ Ω μ- CQ CQ 3 3 Hi Φ CQ Φ 0 Ω 0 i ø 0 Φ 0⁾ H μ- μ- 0 ØJ Ω Φ Φ Φ CQ

Pi 0 CQ μ- rt ζj¹ 0 0 13 μ- CQ 13 CD 3 0 ϋ Φ 3 3 CQ ^■ : 0 Ω rt CQ ØJ μ- rt CQ Hi 0

ØJ 3 tr 0J Φ ø ϋ ri ø CQ ØJ <£> •« 13 ii CQ [~_? 13 CQ tr HT 0 CQ Ω ø HT Hi Hi H μ¹ 0 13 HT LQ ii μ- Φ rt 0 μ- o ϋ ii ØJ μ- Φ H 0 ØJ Φ P. 0 Φ 0 3 Φ o P. Ø μ- φ Φ Ω rt Ω øJ i i øJ => Φ φ LQ H Φ K CQ HT μ- CQ ø LQ £, 0 øJ Ω o H LQ øJ tr φ t 0 CQ CQ 3 ø CQ CQ øJ ø Φ μ- Φ tr Ω Ω ^>< rt 0 tr P μ- tr μ- Pi rt φ P. Φ CQ 0 ø⁾ ø CQ 13 ø 0 CQ 0 z < ØJ Ω Ω ø⁾ μ- 0 rt tr

Φ CQ Hi ii μ- μ- rt Hi 0 0 0 h-¹ 3 ii 0 0 μ- Φ rt ØJ i Ω 3 μ- tr Ω Φ

0 Ω 0 ØJ μ- 0 Hi ø 13 0J P. P. K 0 rt ØJ H tr tr rt μ- • HT 13 0 Φ 0 CQ

Hi ii ø ø rt <! ø μ- LQ 0 LQ Ω P-. μ- *< Ω Φ Φ HT ØJ O ii ø ø φ Pi tr φ ii ii φ 0 tr CQ CQ 0 CD 0 X ø CQ H3 Ω Φ rt 0J rt øJ rt φ 3 CQ Ω rt 3 O Φ rt CQ LQ g 0 3 Pi tr μ- HT tr 0J CQ ØJ tr Pi ii tr CQ 0 rt ø μ- rt 0 CQ μ- 13 tr øJ rt rt μ- & tr 0⁾ 0 μ- Φ CQ 0 ØJ Φ CQ CQ CQ μ- φ φ μ- tr μ- ø rt 3 ø ii μ- LQ 0 0J < μ- Φ 0 ii Hi CQ Hi 13 Φ 0 Ω tr ø C Φ ø μ- tr Ω 13 μ- Φ 0 ø φ LQ φ ø CQ Pi Φ Hi 0 φ tr H PJ " Φ tr

Hi LQ ø μ- rt 0 ii ø rt CQ Hi _^ 0 Φ Ø φ s- Hi φ φ rt φ μ- μ- tr Hi rt rt 3 φ HT CD Ω 0 rt rt 0J 0 rt ii μ- ØJ Hi HT rt H 0J LQ ii 13 CQ μ- μ- Φ- tr 13 CQ Ω Φ 0 rt 0 μ- Φ Ω tr μ- 0 ø tr φ rt Φ Ω 0 μ- Φ 0 ø Ω LQ

CQ ϋ Φ ii ø^j o Φ ii CQ 0 ii HT 3 0 Φ 0 Pi Φ ØJ ø tr 0J HT ii Ω tr ii 0J tr φ rt Φ >P CQ Φ 0 3 3 Φ 3 φ CQ 3 0 ø rt Ω ØJ Ω φ tr 0 μ- H

CQ ø rt CQ Φ CQ i 3 ø ø rt 13 CQ CD rt 13 rt tr Φ 0 CQ 0 Pi φ i CQ φ 13 μ- X CQ ø μ^j 0 CQ ø rt 0J ii 0J $ ØJ rt CQ tr 0 0J 3 <! rt ii 0 0 P. r, 3 rt 0 CQ ø rt tr φ μ- HT LQ Φ 3 0 O μ- s- tr Φ tr Ω rt 13 3 Ω 0 φ tr μ- ii rt H φ μ- Φ i rt μ- μ- Φ Ω Ω Φ Φ CQ φ Hi ii 0 ØJ 0 Φ HT 0 ii ØJ tr H P. 0J

< Φ μ- CQ H ii PJ Ω 1 CQ 0 0J • CQ 13 • 13 CD tr 0 Φ *< 0J ø

Φ P. < CQ ØJ ø CQ LQ ØJ CQ • 0 rt Hi 0 Hi øJ 0 φ ØJ Φ 0J Ω rt CQ ii HT

\. ϋ φ ø K øJ rt Φ rt rt P. μ- μ- ι-3 ϋ 0 0 μ- Hi m CQ 3 • ø 0 tr CQ ØJ LQ 0J 'TJ rt φ H μ- ii 0J μ- ø ι-3 0 ii HT - 0 tr tr Φ P. 3 0 Φ < ø tr ς 0 < 0 Φ rt LQ μ- 0 LQ tr Ω ø CQ Φ Ω Φ CQ P Φ ØJ Hi 13 CQ ii CQ ϋ Φ ϋ Φ

13 Φ ø 0 Ω Φ 0 ø Φ μ- 0 rt 0 € rt CQ ii ϋ ø CQ tr rt ii HT 0 • rt øJ rt μ- μ- 0 •- CQ co 3 £ IT μ- 0 μ- Φ i tr 0 Φ ØJ 0J HT

0 tr ø rt ø øJ 3 rt 3 Ω 13 μ- 13 Φ 0 0J Hi < 0J 0 CQ 13 0 tr t Φ ii

CQ μ- 0 3 øJ Φ μ- 0 3 ϋ rt øJ rt i 0 ø Φ Ω 0 13 ø rt CD Φ tr φ 0J Ω i μ- μ- Q μ- tr ØJ 3 0 0 ØJ rt 3 Φ Φ t μ- HT φ Pi o i Φ 0 HT 0 Φ Ω 0 3 <! o rt ØJ ø 0 P. i tr 13 ØJ CQ K Φ tr ØJ *^. ii ø 3 M 3 CQ CQ HT 0 0 Φ ø Ω CQ CQ HI ϋ ø ω rt "< CQ o μ- 0 0J r « ØJ tr μ- ii ø⁾ μ- rt μ- 0 rt Φ CQ 0 HT 0 0 ϋ <! tr P. 0 Φ 0 ^ 3 0J 0 Ω Φ -

CQ CQ S CQ ϋ μ- rt Hi tr CQ ϋ Φ Hi 0 Φ 0J Φ Φ i ii ø 0 0 13 Hi ØJ - 0 rt Φ μ- 3 CQ 1 CQ Φ CQ rt rt 0J CQ tr tr ØJ 0 φ tr

ØJ •> rt 0⁾ rt CQ rt 0 πr CQ μ- Ω 3 0 - Φ 0 P. Φ rt rt Φ Q tr rt tr ii 0J rt ø Φ HT 0 tr O Hi ~. CQ P. CQ tr CQ φ rt h-¹ øJ Φ rt 0J rt Φ tr 0 rt <! 0 ø^j Φ tr Φ HT PJ LQ LQ Φ CQ rt Φ ii s: CQ ØJ 0J Φ ø φ Φ rt μ- CQ 0 ii tr 13

CQ Φ 0J φ

40, i e the first pair of drive lobes 40a and 40b, are in communication with the inlets of the preferably somewhat larger second drive/expansion stage, i e the second pair of drive lobes, instead of the atmosphere. The inlets of the first drive/expansion stage are in communication with the external combustion chamber 20, as shown in FIG 1. This means that the last drive/expansion stage in the multistage drive/expansion unit would have its inlets in communication with the outlets 100a and 100b of the preceding drive/expansion stage and its outlets 100a and 100b in communication with the atmosphere.

Each of the lobes moves in a circular path around the longitudinal axis of its associated rotating shaft 50, 60, 70 or 80, and due to its essentially half-circular shape an empty volume or cavity is created opposite each lobe seen in the radial direction. This cavity works as a compression chamber 110 in the compressor unit 30 and as an expansion chamber 120 in the drive unit 40 for each lobe. Here, two compressor chambers 110, one for each compressor lobe 30a and 30b, in the compressor unit, and two expansion chambers 120, one for each drive lobe 40a and 40b, in the drive unit are used. The compression of air and the main expansion of gases occur in the associated chamber due to the gear-wheel function and the half-moon shape of the lobes, which enables a reduction and/or an increase of the compression and expansion chambers 110 and 120, respectively.

In FIG. 1 and 2 cooling ducts 130 for cooling the rotary engine 10 are shown schematically. The cooling ducts are located in the housing 11 of the rotary engine and are placed essentially symmetrically around the external combustion chamber 20, the lobes 30a, 30b, 40a, and 40b, and the intake and exhaust channels 90a and 90b and 100a and 100b. Alternatively, these cooling ducts may be placed at any other location fulfilling the cooling requirements as is readily understood by a person skilled in the art. The rotary engine 10 has at least one ignition plug 140 located in each external combustion chamber 20 adjacent the two units 30 and 40, as well as at least one fuel injection system 200, as is clearly shown in FIG 2. In this embodiment , shown in FIG 2 , three gear wheel systems are required for driving and synchronising the rotating parts of the rotary engine. A front gear wheel system 210 is located to the left, a middle gear wheel system 220, which is placed adjacent the compressor unit 30 to the right, and a third gear wheel system 230 further to the right. The front gear wheel system 210 synchronises the rotation of the drive lobes 40a and 40b of the drive unit in relation to each other. The middle gear wheel system 220 synchronises the rotation of the compressor lobes 30a and 30b of the compressor unit in relation to each other. The third gear wheel system 230 functions both as a drive and reversing device for driving the two compressor lobes in the compressor unit and changing the direction of rotation for the two compressor lobes in relation to each other. Each of the compressor lobes 30a and 30b in the compressor unit 30 is attached to its associated hollow rotating shaft 50 and 60, respectively, whereby each hollow rotating shaft is supported by its associated solid rotating shaft 70 or 80. The support of the solid rotating shafts is achieved by way of a bearing between each solid rotating shaft and its associated hollow rotating shaft. The bearing enables axial movements of each compressor lobe in relation to each drive lobe in response to axial loads and/or heat expansion so that no unnecessary loads are built up. The function and location of the gear wheels will be explained in more detail in this description with reference to FIG 3.

FIG 3 shows a top view in section of the rotary engine 10 with the drive unit 40 to the left and the compressor unit 30 to the right. FIG 3A illustrates a side view of the third gear wheel system 230 for clarity reasons. In FIG 3, the synchronising and driving gear wheel systems 210, 220 and 230 are shown in more detail. The front gear wheel system 210 comprises two front gear wheels 211 and 212 in engagement with each other. The front gear wheel 211 is attached to the solid rotating shaft 70 and the other front gear wheel 212 is attached to the solid rotating shaft 80. The middle gear wheel system 220 comprises two middle gear wheels 221 and 222 in engagement with each other. The first middle gear wheel 221 is attached to the hollow rotating shaft 50 and the other middle gear wheel 222 is attached to the hollow rotating shaft 60. The two middle gear wheels 221 and 222 synchronise the mutual rotation of the compressor lobes 30a and 30b and drive the hollow rotating shaft 50 and the first compressor lobe 30a. The third gear wheel system 230 comprises three gear wheels 231, 232 and 233 in engagement with each other. The first gear wheel 231 is attached to the solid rotating shaft 70. The second gear wheel 232 is attached to a separate shaft or pin (not shown) and reverses the direction of rotation for the compressor lobes in relation to the drive lobes. The third gear wheel 233 is attached to the hollow rotating shaft 60, thereby driving the compressor lobe 30b and the middle gear wheel system 220 that drives the other hollow rotating shaft 50 and the other compressor lobe 30a. The change of rotational direction due to the second gear wheel 232 of the third gear wheel system means that, in this embodiment, each compressor lobe rotates in the opposite direction to the associated drive lobe having the same axis of rotation. The first compressor lobe 30a rotates in the opposite direction in relation to the drive lobe 40a and the second compressor lobe 30b rotates in the opposite direction in relation to the drive lobe 40b. The hollow rotating shafts 50 and 60 have the same dimensions except for the length. The hollow rotating shaft 50 is shorter than the hollow rotating shaft <_υ t t *—. o o o rt tr

Φ u μ-

CQ rt

0

0 tr φ rt s-

Φ

Φ ø rt tr

Φ rt s;

0

Φ ø

P- 3

0

CQ μ- rt μ-

0

CQ μ- ø

CQ μ-

Pi φ rt tr

Φ

combustion chamber giving different compression ratios is possible, as is readily understood by a person skilled in the art .

With reference to FIG 4, the piston 410 of the mechanism 400 may be moved by any other means than an electrically driven servomotor 430, for example a hydraulically, pneumatically or mechanically driven motor. The device may also be a membrane connected to the piston, the membrane enclosing a volume that may be increased or decreased by filling it or emptying it with a fluid, thereby pushing the piston back and forth. Alternatively, the membrane could be in direct contact with the combustion chamber 20, i e it could be integrated as a part or in whole of an inner wall in the combustion chamber. Then, an increase or decrease of fluid in the volume enclosed by the membrane would increase or decrease the volume of the combustion chamber in relation to the bulging or curving membrane .

Figs. 5-6 illustrate another embodiment of the rotary engine 10 in a view similar to Figs. 1-2. Here, the same numerals are used as in Figs. 1-4. In FIG 5, the construction of the drive lobes 40a and 40b, the two expansion chambers 120, and the exhaust ports 100a and 100b are essentially the same as for the embodiment illustrated in FIG 1. The only difference is the shape of the exhaust ports 100a and 100b. The exhaust ports 100a and 100b are somewhat wider in FIG 5 compared to FIG 1. However, the main differences between the embodiment in Figs. 1-4 and this embodiment are apparent by comparing the compressor unit 30, associated attachment, driving and synchronising means together with the shape of the external, common combustion chamber 20 in the two embodiments with reference to Figs. 1-4 and 5-6, respectively.

In FIG 6 the compressor unit 30 is located to the right and the drive unit 40 to the left as in FIG 2. In this embodiment, all of the lobes, i e the compressor and drive lobes 30a, 30b, 40a and 40b, are attached to the rotating shafts 70 and 80, thereby eliminating the need for the hollow rotating shafts 50 and 60 in the first embodiment in Figs. 1-3. This means that the compressor lobe 30a has the same direction of rotation as the drive lobe 40a, and the compressor lobe 30b has the same direction of rotation as the drive lobe 40b but in the opposite direction compared to the lobes 30a and 40a. For synchronising and driving the two units 30 and 40 only the front gear wheel system 210, shown to the left, which comprises the two gear wheels 211 and 212, is required. The middle and third gear wheel systems 220 and 230 in the first embodiment shown in FIG 2 is therefore eliminated in this embodiment. The front gear wheel system 210 synchronises the solid rotating shaft 70 and the associated compressor lobe 30a and drive lobe 40a in relation to the other solid rotating shaft 80 and the other compressor lobe 30b and drive lobe 40b. The appropriate synchronisation of each compressor lobe 30a or 30b in relation to its associated drive lobe 40a or 40b is achieved by turning the corresponding two lobes 30a and 40a, or 30b and 40b into the proper angle, i e in an angular displacement, in relation to each other. After that, the drive lobe and associated compressor lobe are firmly attached to the rotating associated shaft 70 or 80.

Other differences between the first embodiment in FIG 2 and the second embodiment of the rotary engine 10 in FIG 6 refer to the shape of the external common combustion chambers 20 and the location of the intake ports 90a and 90b for the compressor unit 30. Here, in FIG 6, the inlets 20a of the combustion chambers are located below the compressor unit 30 (compare with FIG 2) , and the outlets 20b are located above the drive unit 40, as in FIG 2. This makes the combustion chambers longer, whereby the location and number of ignition plugs 140 may have to be changed in relation to the first embodiment in FIG 2, so that a sufficient combustion is achieved. The location and number of nozzles for the fuel injection system 200 may also have to be changed for the same purpose as the ignition plugs. The intake ports 90a and 90b for intake of air into the compressor unit is placed above the compressor unit in FIG 6 in comparison with the intake ports placed below the compressor unit in the first embodiment shown in FIG 2. In this second embodiment, the rotary engine 10 may be redesigned or simply turned upside down, whereby the inlets and outlets of the combustion chambers, and the intake and exhaust ports would be placed in opposite positions in relation to FIG 6. Figs. 7-14 illustrate the drive/expansion and compressor cycle for the drive and compressor units 30 and 40, respectively, in the first embodiment of the rotary engine 10 shown in Figs. 1-2. Figs. 7-10 show four phases in the drive/expansion cycle, and Figs. 11-14 show four phases in the compressor cycle. In Figs. 7-10, the drive lobe 40a to the left rotates in the counter-clockwise direction and the drive lobe 40b to the right rotates in the clockwise direction. In Figs. 11-14, the compressor lobe 30a to the left rotates in the clockwise direction and the compressor lobe 30b to the right rotates in the counter-clockwise direction.

In FIG 7, the outlet 20b of the external combustion chamber 20 in communication with the drive lobe 40a is being opened in that the involute-shaped end 40' of the drive lobe passes the outlet 20b. At this moment, the exhaust outlet 100a has been open since about half a revolution of the drive lobe 40a, i e about 180°, and has been emptying the expansion chamber 120 from the exhaust gases of the prior combustion and expansion. The other outlet 20b of the other combustion chamber in communication with the drive lobe 40b has also been open for about half a revolution, i e about 180°.

In this position, shown in FIG 7, for the drive lobe 40b to the right, the combustion and drive cycle is completed and its associated exhaust outlet 100b is being opened. Now, the discharge of exhaust gas from the combustion chamber 20 and the expansion chamber 120 to the right starts and the combustion chamber, i e the outlet

20b, is closed by the drive lobe 40b when its involute- shaped end 40' passes the outlet. When the drive lobe 40b closes the combustion chamber to the right, the compressor lobe 30b opens its inlet 20a of the combustion chamber and simultaneously closes its intake port 90b. Then, the compressor lobe 30b starts its compression cycle, as shown in FIG 13, while the drive lobe 40b discharges the exhaust gas from the prior combustion cycle.

During a short while in FIG 13 there is a free passage formed between the two compressor lobes 30a and

30b. This means that the remaining amount of compressed air in the other compressor lobe 30a flows into the compression chamber 110 of the compressor lobe 30b and is added to the compression cycle. After this, the compressor lobe 30b compresses the air during about half a revolution, i e about 180°, until its involute-shaped end 30' reaches the associated inlet 20a of the combustion chamber and subsequently closes it. This is shown in FIG 14 just before the involute-shaped end reaches the inlet 20a of the combustion chamber.

In FIG 14, when the compressor lobe 30b has closed the inlet 20a of its associated combustion chamber 20, the drive lobe 40b opens the outlet 20b of its associated combustion chamber. Just before the drive lobe 40b opens its outlet 20b the other drive lobe 40a has closed the free way between the two lobes, so that the combustion and subsequent expansion cycle for the drive lobe 40b can start. Simultaneously, or just before the combustion chamber is opened in that the involute-shaped end 40" of the drive lobe 40b reaches the outlet 20b, as shown in FIG 10, the combustion is ignited by the ignition plugs 140 (not shown) . The involute-shaped end 40" of the drive lobe 40b passes the outlet and the combustion gas discharges from the combustion chamber during expansion. The gas flows into the expansion chamber 120, thereby increasing the pressure against the inner walls of the expansion chamber. This means that the involute-shaped end 40" and its surface, which is perpendicular to the direction of rotation, i e extends in the axial/longitudinal direction of the rotating shaft 70 and 80, are pressed/moved in the clockwise direction, thereby rotating the drive lobe 40b. The expansion of the combustion gas starts shortly after the involute-shaped end 40" of the drive lobe 40b has passed the position shown in FIG 10. The expansion of the combustion gas ends just before or in the same moment as the drive lobe 40b opens its exhaust port 100b when its involute-shaped end 40" reaches the exhaust port about half a revolution later, as shown in FIG 7.

In FIG 7, the drive lobe 40a located to the left is shown in its position just before its expansion/drive cycle starts, i e when the drive lobe 40a opens the outlet 20b of its associated combustion chamber 20. This means that the compressor lobe 30a just has or is about to end its compressor cycle by closing its inlet 20a of the associated combustion chamber. In essentially the same moment, as shown in FIG 12, the compressor lobe 30a to the left has just ended or is ending its compression cycle and closes or has just closed the inlet 20a of its associated combustion chamber, and the at least one ignition plug 140 (not shown) ignite or is about to ignite the combustion. The combustion starts and the combustion gas discharges out of the combustion chamber and flows into the expansion chamber 120 of the drive lobe 40a. The involute-shaped end 40' of the drive lobe 40a is pushed/pressed by the increased pressure due to the gas expansion against the inner walls of the expansion chamber forcing the drive lobe 40a into rotation in the counter-clockwise direction. The drive lobe 40a is driven/rotated about half a revolution, i e about 180°, by the gas expansion until the involute-shaped end 40' reaches the exhaust port 100a, where the exhaust/discharge of exhaust gas starts. A short while or a certain angle, preferably between 10° and 50° of revolution, after the exhaust port 100a has been opened, the outlet 20b of the combustion chamber associated with the drive lobe 40a is closed when its involute-shaped end 40" passes the outlet. During the expansion/drive cycle for the drive lobe 40a the compressor lobe 30a has rotated about half a revolution, i e about 180°, and sucked in a new amount of air from its intake port 90a.

When the drive lobe 40a closes the outlet 20b the compressor lobe 30a closes its intake port 90a as its involute-shaped end 30' passes it and starts compressing the new air, as is shown in FIG 14. The compression of air is performed during about half a revolution of the compressor lobe 30a, i e about 180° of revolution, until the involute-shaped end 30' passes the inlet 20a of the associated combustion chamber 20 and closes it, as shown in FIG 12. FIG 13 shows another position of the compressor lobe 30a a short while after the closing of the combustion chamber in FIG 12.

In FIG 8 the optimal position for opening the exhaust port 100a of the drive lobe 40a is shown. Here, the discharge of exhaust gas from the expansion chamber 120 to the left is about to take place. Shortly thereafter, the expansion or drive cycle for the drive lobe 40b is about to start when its involute-shaped end 40" passes the outlet 20b of the combustion chamber 20 to the right. OJ t t

KM o KM o KM o KM

weight or eccentric. This means that the centre of mass for each lobe is displaced in the radial direction of the associated rotating shaft and does not coincide with the centre of the shaft. Therefore, vibrations in the rotary engine 10 may occur. However, this can be perfectly counter-balanced by placing a counter-weight, which corresponds to the unbalance created by its associated lobe, in the appropriate opposite position in relation to its associated lobe, at the associated gear wheel, which drives and/or synchronises the associated lobe.

Furthermore, each or at least two of the lobes 30a, 30b, 40a and 40b may have a shape/profile corresponding to the shape of a screw in a screw compressor for achieving the same function as a screw compressor.

Engine Housing First end part Second end part First separating part Second separating part Middle part External combustion chamber a A pair of inlets of the combustion chamber b A pair of outlets of the combustion chamber First unit (compressor unit) a First rotating part (first compressor lobe) b Second rotating part (second compressor lobe) Second unit (drive unit) a First rotating part (first drive lobe) b Second rotating part (second drive lobe) First rotating shaft (first hollow shaft) Second rotating shaft (second hollow shaft) Third rotating shaft (first solid shaft) Fourth rotating shaft (second solid shaft) a Intake port (to the left) b Intake port (to the right) 0a Exhaust port (to the left) 0b Exhaust port (to the right) 0 Compression chamber 0 Expansion chamber 0 Cooling ducts 0 Ignition plug 0 Fuel injection system 0 Front gear wheel system 1 First front gear wheel 2 Second front gear wheel 0 Middle gear wheel system 1 First middle gear wheel 2 Second middle gear wheel 230 Third gear wheel system

231 First gear wheel

232 Second gear wheel

233 Third gear wheel

400 Mechanism for variable compression

410 Piston

420 Piston stem

430 Motor

Claims

1. A combustion engine (10) comprising compression and drive units (30,40) with co-rotating elements

(30a, 30b, 40a, 40b) and at least one external combustion chamber (20) in fluid communication with the units, each of the units (30,40) has two co-operating lobes (30a, 30b, 40a, 0b) rotatable in a housing on shafts (50,60,70,80) with opposite rotational directions, the respective lobe shafts of the units being in connection with each other, and the lobes are arranged to control the inlet (20a) and outlet (20b) to and from the at least one combustion chamber and the atmosphere, c h a r a c t e r i z e d in that the outlet (20b) of the at least one combustion chamber (20) extends radially towards its associated lobe (40a, 40b) of the drive unit (40) .

2. A combustion engine (10) according to claim 1, wherein the lobe shafts (50,60,70,80) are in connection with each other by drive and synchronising means (210-233) in the form of gear wheels.

3. A combustion engine (10) according to claim 1 or

2, wherein the rotating lobes (30a, 30b, 40a, 40b) rotate with an angular displacement in relation to each other.

4. A combustion engine (10) according to claim 1, wherein each rotating lobe (30a, 30b) in the compressor unit

(30) rotates in the same direction as its associated rotating lobe (40a, 40b) in the drive unit (40) .

5. A combustion engine (10) according to claim 1, wherein each rotating lobe (30a, 30b) in the compressor unit

(30) rotates in the opposite direction in relation to its associated rotating lobe (40a, 40b) in the drive unit (40) .

6. A combustion engine (10) according to any of the preceding claims, wherein each of the rotating lobes

(30a, 30b, 40a, 40b) is shaped as a semi-circular lobe, preferably a half-circular lobe, whereby a chamber (110,120) corresponding to the remaining empty volume opposite each rotating lobe is formed.

7. A combustion engine (10) according to claim 6, wherein each rotating lobe (30a, 30b, 40a, 40b) is attached to its associated rotating shaft (50,60,70,80) in the same way as an counter-weight or eccentric, whereby a counter-weight is attached in the appropriate position opposite the associated rotating lobe so that the unbalance created by the lobe during rotation is perfectly counterbalanced.

8. A combustion engine (10) according to any of the preceding claims, wherein the volume of the external combustion chamber (20) is variable by way of an adjustable mechanism (400) with a part (410) movable in one direction for reducing the volume and in another direction for increasing the volume of the external combustion chamber.

9. A combustion engine (10) according to any of the preceding claims, wherein the rotating lobes (30a, 30b) in the compressor unit (30) have the same cross-section and length as the rotating lobes (40a, 40b) in the drive unit (40) .

10. A combustion engine (10) according to any of the preceding claims, wherein the rotating lobes (30a, 30b) in the compressor unit (30) have the same cross-section as the rotating lobes (40a, 40b) in the drive unit (40) but are thicker or longer in the axial direction.

11. A combustion engine (10) according to any of the preceding claims, wherein the rotating lobes (30a, 30b) in the compressor unit (30) have a different cross-section in comparison to the rotating lobes (40a, 40b) in the drive unit (40) .

12. A combustion engine (10) according to any of the preceding claims, wherein the rotating lobes (30a, 30b) in the compressor unit (30) have a varying cross-section in the longitudinal direction, i e a conical shape, in comparison to the rotating lobes (40a, 40b) in the drive unit (40) .

13. A combustion engine (10) according to any of the preceding claims, wherein the rotating lobes (30a, 30b) in the compressor unit (30) have the same cross-section as the rotating lobes (40a, 40b) in the drive unit (40) but have a conical shape in the axial direction.

14. A combustion engine (10) according to any of the preceding claims, wherein the outlet (20a) of the at least one external combustion chamber (20) is formed as an expansion nozzle in communication with the drive unit (40) .

15. A combustion engine (10) according to claim 7, wherein each corresponding counter weight is placed opposite but not in the same plane as the associated rotating lobe.

16. A combustion engine (10) according to any of the preceding claims, wherein at least two compression units (30) are in communication with each other in that a first compression unit has its outlets in communication with the inlets of a subsequent compression unit, which in turn has its outlets in communication with the external combustion chamber (20) , whereby the at least two compression units perform a compressor function similar to a multi-stage compressor.

17. A combustion engine (10) according to any of the preceding claims, wherein at least two drive units (40) are in communication with each other in that a first drive unit has its outlets in communication with the inlets of a subsequent drive unit, which in turn has its outlets in communication with the atmosphere, whereby the at least two drive units perform an expansion function similar to a multi-stage turbine.