WO2017116369A1

WO2017116369A1 - Exhaust gas recirculation system which takes advantage of the pressure pulsations

Info

Publication number: WO2017116369A1
Application number: PCT/TR2016/050549
Authority: WO
Inventors: Volkan ARAN; Cetin GUREL; Onur BARIS
Original assignee: Ford Otomotiv Sanayi A.S.
Priority date: 2015-12-30
Filing date: 2016-12-28
Publication date: 2017-07-06

Abstract

The present invention relates to an exhaust gas recirculation system (1) which takes advantage of the pressure pulsations, which moves so as to catch the pulsations stemming from the intermediate junction of two or more cylinder exhausts, or which rotates continuously, and which operates synchronously with the exhaust timing of the engine.

Description

SPE C IFICATIONS

EX HA UST GAS R E CIRC U LAT ION SY ST E M W H IC H TA K E S A DVANTAG E OF T H E PR E SSU R E PU L SAT IONS F i el d of the I nventi on

The present invention relates to an exhaust gas recirculation system which takes advantage of the pressure pulsations, which moves so as to catch the pulsations stemming from the intermediate junction of two or more cylinder exhausts, or which rotates continuously, and which operates synchronously with the exhaust timing of the engine.

Background of the Invention In the internal combustion engines, some harmful gasses such as carbon monoxide (CO), nitrogen oxide (NOx), hydrocarbon (HC) emerge as the result of the combustion. Releasing of these harmful gasses which emerge as the result of the combustion directly to the atmosphere is extremely dangerous for the environment and the health of the living beings, and it is prohibited. Before releasing these harmful gasses which emerge as the result of the combustion to the atmosphere, they have to be reduced to the levels which are defined by the regulations. In the internal combustion engines, there are a lot of systems and applications in order to reduce the harmful gasses to acceptable emission values. One of these applications is the exhaust gas recirculation, exhaust gas recycling (EGR) system. In the EGR system, some amount of the exhaust gasses is rei ncl uded i n the combusti on process. Some gasses which emerge as the result of the combustion in the engine are not burnt in the engine, they reduce the combustion temperature of the engine, and hence cause the harmful gasses to be exhausted through the exhaust system. By the E GR system, these gasses that are not f ul ly burnt i n the engi ne are rei ncl uded i n the combustion process and thus the combustion temperature of the engine is reduced and the forming of the nitrogen oxide gas is reduced. The presently used EGR systems is connected to the exhaust manifold via a pipe, and it sends the exhaust gas to the i ntake manif ol d. T he f I ow of the E G R gas to the intake manifold is possible if and only if the pressure at the exhaust manifold is greater than the pressure at the i ntake manif ol d, and the pressure difference at some working points does not give an opportunity to send high rates of E GR and/or to send the exhaust gas to the manifold. Especially at lower revolutions where the highest torque is given, it might not be possi bl e to send the exhaust gas to the i ntake manifold in diesel engines. In such cases, assistance is taken from actuators such as variable geometry exhaust turbocharger valve which increases the recycling pressure of the exhaust gas. The increased exhaust pressure causes the engine to spend more fuel in order to yield the same torque. In the other method that is applied for the insufficient exhaust pressure, recycling lines for the low-pressure exhaust gasses are added. In this application, a line from the output of the turbine to the input of the compressor is installed, and with this line, it is enabled that the gas flows into the manifold whenever desired. However, this additional line brings along durability risks for the compressor and the parts of the intake manifold, and an additional cost. Another technical problem of the presently used E GR systems is that the EGR valves are designed in order to use the static pressure difference at the exhaust manifold. The opening and closing reaction times of the E GR valves are not appropriate to react at the speed of the crank shaft. The present techniques are developed towards controlling the flowrate of the E GR independently from the angl e of the crank. T he f I owrate of the E G R cannot be control I ed at the crank angl e speed using the presently used throttle, conical valves, and unsynchronized actuators. There are fast rotating valves present which are more adequate for the crank speed, and which are used for catching the pressure pulsations at the intake manifold. However, these valves aim to momentarily reduce the intake pressure, they do not ai m to use the exhaust pressure of the system. T he said valves are driven and their speeds are controlled by an electric motor. The said valves are designed as rotati ng, butterfly and conical, they cannot rotate operati ng accordi ng to the crank angle, and at high speeds, they cannot rotate at the multiples of the angular speeds of the engine, they are not suitable for the time interval and input output selection. In another application that is used in the present technique, in order to use the pressure pul sati ons, passive systems cal I ed " R eed V al ves" are added on the exhaust. However, these systems cause very high losses of pressure, and this situation, in turn, causes loss in efficiency, and increases the energy that is spent by the compressor. Y et in another application, by applying venturi (Haldex Varivent V enturi) to the E G R i nput at the cl ean ai r i nput si de of the engi ne, the f I ow of the exhaust gas is made easy. However, as well in this system, a pressure loss in experienced, and in order to reach the same manifold pressure, the required manifold pressure is increased. In the E G R system that are used i n the present technique, generally the exhaust gas is sent to the intake manifold with the help of a valve. The valves that are used in these applications are not of a structure that can adapt to the speed of the crank. On the other hand, various technical problems are experienced while adapting the valves that can operate in accordance with the speed of the crank shaft to the E GR system. The valves that can operate compatibly with the speed of the crank shaft cause pressure I osses and i ncrease the fuel consumpti on. T he additi onal compressor lines that are included in the system in order to overcome this problem, in turn, bring additional costs. In the U nited States patent document numbered U S6116223 i n the background of the invention, cam mechanism is used in order to move the timing of the EGR valves simultaneously with the exhaust valves. In order to install the suggested system structure in the said document, changes have to be made in the base engine design. In the patent and utility model documents numbered US6116223, US5435519 and C N202970959 in the background of the invention, also similar technical problems are present. T he criteria that is taken i nto account whi I e di recti ng the exhaust gas to the i ntake manifold is the difference of pressure. In the internal combustion engines, the times when the exhaust pressure is the highest at the output of every cylinder are the outputs of the cylinders which are at the exhaust stroke at that time, and the said cylinder goes to the intake stroke when the crank shaft turns a little bit more, and the exhaust pressure drops. With the invention that is the subject of the application, the high exhaust pressure is connected to the intake manifold, and thus the flow potential of the exhaust gas which is directed to the intake manifold is held at the maximum level. With the patent that is the subject of the application, a system which is simultaneous with the speed of the engine, and which will connect the appropriate cylinder output or outputs to the intake manifold at every pulsation is developed.

Obj ects of the Invention The object of the invention is to realize an exhaust gas recirculation system which takes advantage of the pressure pulsations which increases the potential of the flow of the E G R by usi ng the pressure pulsati ons at the i nput of the E G R system.

Another object of the invention is to realize an exhaust gas recirculation system which takes advantage of the pressure pulsations, which connects the high exhaust pressure to the intake manifold, and thus holds the flow potential of the exhaust gas which is directed to the intake manifold at the best level.

Y et another object of the invention is to realize an exhaust gas recirculation system which takes advantage of the pressure pulsations which operates simultaneously with the engine speed. Y et another object of the invention is to realize an exhaust gas recirculation system which takes advantage of the pressure pulsations, which can utilize the pressure pulsations at the input of the E GR system, and in which the exhaust inputs and outputs can be selected by the virtue of the multiple input valve.

Y et another object of the invention is to realize an exhaust gas recirculation system whi ch takes advantage of the pressure pul sati ons whi ch uti I i zes the present potenti al by taking advantage of the pulsations which arise during the combustion in the engine, and which renders the potential that is generated during the combustion usable without generating additional exhaust pressure, solely by preventing dampening.

Y et another object of the invention is to realize an exhaust gas recirculation system whi ch in overfed engi nes regul ates the turbi ne i nput pressure usi ng the E G R system, whi ch balances the pul sati ons at the i nput of the turbi ne and thus enabl es i ncreasi ng of the efficiency of the turbine.

Short Description of the Invention

In the exhaust gas recirculation system that is defined in the first claim and the dependent claims thereof in order to realize the objects of the present invention, a flow control valve or disk is connected between the exhaust output of the cylinder and the intake manifold. The flow control valve or disk is controlled via an electric motor or according to the operation of the engine. Here, the movement can be controlled by a timing belt, as well as it can be achieved by an extra motor having a phase control. By the movement of the flow control valve or disk, the appropriate cylinder exhaust output is connected to the intake manifold. It can be applied in all the situations where exhaust manifold can be connected by a single piece, or cylinder groups or individually. The flow control valve or disk rotates continuously or i n a ti med manner, operati ng synchronously with the exhaust ti mi ng of the engi ne ( M) i n order to catch the cyl i nder exhaust pulsations. T he flow control valve or disk continuously connects the high exhaust pressure to the intake manifold, thus keeping the flow potential of the exhaust gas at the best level. Detailed Description of the Invention

An exhaust gas recirculation system realized in order to fulfill the objects of the present invention is illustrated in the attached figures, where: F igure 1. Schematic view of the exhaust gas recirculation system.

F igure 2. Schematic view of the flow control valve that is used inside the exhaust gas recirculation system.

F igure 3. Schematic view of the flow control valve and the driving apparatus. F igure 4. Schematic view of the flow control valve in another position.

F igure 5. Schematic view of the engine, the intake manifold, and the cylinder exhaust output.

F igure 6. Schematic view of the connection of the flow control disc and the belt pulley.

F igure 7. Schematic view of the moving discs.

F igure 8. Schematic view of the fixed disc.

E lements shown in the figures are individually numbered, and the correspondence of these numbers are given as f ol I ows: 1. Exhaust gas recirculation system.

2. Cylinder exhaust output

21. First output

22. Second output

3. Turbine

4. Gas return line

5. Intake manifold 6. Flow control valve

61. First exhaust input

62. Second exhaust input

63. Manifold output

64. Body

7. Driving apparatus

8. Flow control disc

81. First moving disc

82. Fixed disc

83. Second moving disc

84. Belt pulley mounting piece

85. Channel

86. Hole M . E ngine

K . Belt pulley

The exhaust gas recirculation system (1) which takes advantage of the pressure pulsations, which moves so as to catch the pulsations stemming from the i ntermedi ate j uncti on of the cyl i nder exhausts of the engi ne ( M ), or whi ch rotates continuously, and which operates synchronously with the exhaust timing of the engine comprises;

- at least one cylinder exhaust output (2) which has more than one cylinders,

- at I east one gas return I i ne (4) whi ch carri es the exhaust gas stemmi ng from the cylinder exhaust output (2) to the intake manifold (5),

- at least one flow control valve (6) and/or flow control disc which is connected to the cylinder exhaust output (2), which is directed to one of the cylinder exhaust outputs (2) according to the exhaust timing of the engine, and which enables the exhaust gas to be directed to the intake manifold (5). By the inventive exhaust gas recirculation system (1), in every pulsation the appropriate cylinder output or outputs are caught synchronously with the engine (M) speed and connected to the intake manifold (5), the exhaust gas is directed to the intake manifold synchronously with the exhaust openings.

By the i nventive exhaust gas reci rculati on system ( 1 ) it became possi bl e to receive more power from the turbine (3) by balancing the pressure fluctuations that are formed in the exhaust manifold. By this way, a higher intake manifold (5) pressure is achieved by a lower exhaust pressure, and thus a better fuel consumption is achieved.

In an embodiment of the application, the waste gas that is formed during the operati on of the engi ne ( M) arrives to the cyl i nder exhaust output (2). T he cyl i nder exhaust output (2) might be of different structures depending on the type of the engine (M) and its number of cylinders. In an embodiment of the invention, the cylinder exhaust output (2) comprises at least one first output (21) and at least one second output (22). The first output (21) and the second output (22) can change depending on the number of cylinders of the engine (M) or the groups of exhaust manifolds. In an embodiment of the invention, there is one output for every one of the cyl i nders of the engine (M).

In an embodiment of the invention, the cylinder exhaust output (2) is connected to the turbine (3). The turbine (3) rotates with the exhaust gas pressure that is stemmi ng from the cyl i nder exhaust output (2) .

In an embodiment of the invention, a gas return line (4) is present between the cylinder exhaust output (2) and the intake manifold (5). The gas return line (4) carries the exhaust gas generated during the combustion from the cylinder exhaust output (2) to the intake manifold (5). The gas return line (4) is utilized when the exhaust gas at the cylinder exhaust output (2) is going to be directed to the combustion chamber of the engine (M9 again, in other words, when the EGR system is going to be activated.

In an embodiment of the invention, the exhaust gas flow that is realized via the gas return line (4) is controlled via the gas control valve (6). The flow control valve (6) is activated when the gas that is taken from the cyl i nder exhaust output (2) is goi ng to be redirected to the intake manifold (5), and enables the flow of the exhaust gas.

In an embodiment of the invention, the flow control valve (6) is a three-way valve and it preferably comprises at least one first exhaust input (61), at least one second exhaust input (62) and at least one manifold output (63). The first exhaust input (61), the second exhaust input (62) and the manifold output (63) are located on the body (64). In an embodiment of the invention, the body (64) is moveable, and according to the moving direction of the body (64), the first exhaust input (61) and the second exhaust i nput (62) are connected to the cyl i nder exhaust output (2), and the manifold output (63) is connected to the intake manifold (5) via the gas return I i ne (4) . T he f i rst exhaust i nput (61 ) and the second exhaust i nput (62) are connected to the cylinder exhaust output (2). The amount of the exhaust gas that is going to flow to the intake manifold (5) is adjusted using the flow control valve (6). The flow control valve (6) is driven preferably by a driving apparatus (7) or a similar device (Figure 3). The driving apparatus (7) that drives the flow control valve (6) operates at a suitable speed and phase with respect to the angle of the valve and/or the crank shaft. In here, the driving force that is transmitted to the valve is preferably transmitted to the crank shaft via a timing belt directly or via a power transmitting method that can enable synchronizing, via a sprocket/pulley. The driving apparatus (7) that controls the flow control valve (6) is adapted to operate in order to connect to the i ntake manifold (5) at the ti me when the exhaust pressure is high. T he drivi ng apparatus (2) is adapted to connect the related exhaust output (2) to the intake manifold (5) at the time when the exhaust pressure is high. The driving apparatus (7) if preferably connected to the crank indirectly via simultaneous/synchronous transmission members such as a timing belt chain, or the like, or pneumatic, hydraulic, or electric driven. The driving apparatus (7) can totally close the gas passage to the i ntake manifold (5) by movi ng the flow control valve (6) i n different manners. The flow control valve (6) can rotate proportionally with the speed of the engine (M) and simultaneously with the exhaust times as well as it can move and it can be moved at certai n positi ons.

In an embodiment of the invention, the operation of the exhaust gas recirculation system (1) is as follows: The flow control valve (6) is connected between the cylinder exhaust output (2) and the intake manifold (5). The flow control valve (6) is moved by the driving apparatus (7). The flow control valve (6) preferably moves circularly. The first exhaust input (61) and the second exhaust input (62) are connected to the cyl i nder exhaust outputs (2) with the movement of the f I ow control valve (6). The flow control valve (6) rotates continuously or in a timed manner, operati ng synchronously with the exhaust ti mi ng of the engi ne ( M) i n order to catch the cylinder exhaust (2) pulsations. By the rotating movement of the flow valve (6), the first exhaust input (61) or the second exhaust input (62) is connected to the cylinder exhaust output (2) on which the pulsation takes place, and the exhaust gas is directed to the intake manifold (5). By this way, the flow control valve (6) selects the exhaust of which ones of the two or more cylinders is going to be sent to the intake manifold (5). The flow control valve (6) continuously connects the high exhaust pressure to the intake manifold (5), thus keeping the flow potential of the exhaust gas at the best I evel . T he f I ow control valve (6) connects the exhaust output (2) to the intake manifold (5) at the time when the pressure is high, synchronously with the speed of the engine (M).

In an embodi ment of the i nventi on, the di recti ng of the exhaust gas that i s stemmi ng from the cylinder exhaust output (2) to the intake manifold (5) or to the gas return line (4) is enabled by the flow control disc (8). The flow control disc (8) is controlled by the driving apparatus (7). The flow control valve (8) controls the amount of the exhaust gas that is going to flow to the intake manifold by turning the flow control disc (8). In an embodiment of the invention, the flow control disc (8) is preferably connected to the belt pulley of the timing belt (K) using the belt pulley mounting piece (84), and it rotates circularly depending on the movement of the belt pulley (K). The flow control disc (8) comprises at least one first moving disc (81), at least one fixed disc (82), at least one second moving disc (83) and belt pulley mounti ng pi ece ( 84) .

The first moving disk (81) can be rotated by a driving apparatus (7) as well as working by receiving the driving force from the engine (M) via a belt or a chain. T he f i rst movi ng di sc ( 81 ) operates so as to al I ow the gas f I ow when the gas pressure at the cylinder exhaust output (2) is high. In order to achieve this timing, a channel (85) which makes the flow of the gas possible is present on the moving disc in a manner that it reciprocates a certain exhaust opening angle. The fixed disk (82) is present right under the fi rst movi ng disk (81 ). T he fixed disk (82) is preferably i n a shape of half a disc. The fixed disc (82) allows the flow only when the pressure of the exhaust gas is high, and additionally, it can stop the flow of the exhaust gas with the help of the second moving disc (83) at the preferred time. The second moving disc (83) is preferably under the fixed disc (82). The second moving disc (83) enables adjusting of the flowrate of the exhaust gas and when preferred it enables stopping the flow according to its position. The second moving disc (83) can be driven by an electric motor.

T he f i rst movi ng disc (81 ) and the second movi ng disc (83) are present on the front and the back of the flow control disc (8), and between these moving discs (81, 83) the fixed disc (82) is present. T he movi ng discs (81 , 83) rotate around the fixed disc (82).

In an embodiment of the invention, the first moving disc (81), the second moving disc (83) and the fixed disc (82) are present inside an enclosed body. According to the rotation of the moving discs (81, 83), when the channels (85) that are on the moving discs (81, 83) overlap with the hole (86) that is on the fixed disc (82), the exhaust flow is enabled from inside the control disc (8). Unless the channels (85) overlap with the hole (86), no exhaust gas flow from the flow control disc (8) takes place. The channels (85) can preferably be in a circular shape, and in the sizes of half a circle, quarter a circle. In an embodiment of the invention, the operation of the exhaust gas recirculation system (1) is as follows: The flow control disc (8) is connected between the cylinder exhaust output (2) and the intake manifold (5). The flow control disc (8) is moved by the driving apparatus (7) or is driven by connecting to the belt pulley (K) of the engine (M). There are two moving discs (81, 83) and a fixed disc (82) present inside the f I ow control di sc ( 8) . T he movi ng di scs ( 81 , 83) al I ow the gas f I ow, i n a manner that their openings are adjusted according to the time when the gas pressure at the cylinder exhaust output (2) is high. The moving discs (81, 83) rotate according to the operation of the engine (M) and allow the gas flow from inside the channels (85) at the times when the gas pressure is high. By this way, the flow control disc (8) continuously connects the high exhaust pressure to the intake manifold (5), thus keepi ng the f I ow potenti al of the exhaust gas at the best I evel . T he f I ow control di sc (8) connects the exhaust output (2) to the intake manifold (5) at the time when the pressure is high, synchronously with the rotation of the engine (M).

Claims

C L AIM S

1. An exhaust gas reci rcul ati on system ( 1 ) whi ch takes advantage of the pressure pulsations, which moves so as to catch the pulsations stemming from the intermediate junction of the cylinder exhausts of the engine (M), or which rotates conti nuously, and whi ch operates synchronously with the exhaust ti mi ng of the engine, comprising;

- at least one cylinder exhaust output (2) which has more than one cylinders,

- at I east one gas return I i ne (4) whi ch carri es the exhaust gas stemmi ng from the cylinder exhaust output (2) to the intake manifold (5), and characterized by

- at least one flow control valve (6) and/or flow control disc which is connected to the cylinder exhaust output (2), which is directed to one of the cylinder exhaust outputs (2) according to the exhaust timing of the engine, and which enables the exhaust gas to be directed to the intake manifold (5).

2. An exhaustgas recirculation system (1) according to Claim 1 characterized by the flow control valve (6) comprising at least one first exhaust input (61), at least one second exhaust input (62), at least one manifold output(63) and a body (64) and which is preferably a three-way valve.

3. An exhaustgas recirculation system (1) according to Claim 2 characterized by the moving body (64) on which the first exhaust input (61), the second exhaust input (62), and the manifold output (63) are present.

4. An exhaustgas recirculation system (1) according to Claim 1 characterized by the flow control valve (6) which comprises the body (64) which connects the first exhaust input (61) and the second exhaust input (62) consecutively to the cylinder exhaust output (2), and which connects the manifold output (63) to the intake manifold (5) via the gas return line (4).

5. An exhaustgas recirculation system (1) according to Claim 1 characterized by the driving apparatus (7) that is adapted to drive the flow control valve (6), operate it at a suitable speed and phase with respect to the angle of the valve and/or the crank shaft.

6. An exhaustgas recirculation system (5) according to Claim 5 characterized by the driving apparatus (7) that is adapted to operate so as to connect the flow control valve (6) to the intake manifold at the time when the exhaust pressure is high.

7. An exhaustgas recirculation system (5) according to Claim 5 characterized by the drivi ng apparatus (7) that is adapted to total ly close the gas flow to the i ntake manifold (5) by moving the flow control valve (6) in different ways.

8. An exhaustgas recirculation system (1) according to Claim 1 characterized by the flow control valve (6) which rotates continuously or in a timed manner, operati ng synchronously with the exhaust ti mi ng of the engi ne ( M ) i n order to catch the cylinder exhaust (2) pulsations.

9. An exhaustgas recirculation system (1) according to Claim 1 characterized by the flow control valve (6) which selects the exhaust of which ones of the two or more cylinders is going to be sent to the intake manifold (5), and which is adapted to continuously connect the high exhaust pressure to the intake manifold (5).

10. T he exhaust gas recirculation system (1) which takes advantage of the pressure pulsations, which moves so as to catch the pulsations stemming from the intermediate junction of the cylinder exhausts of the engine (M), or which rotates conti nuously, and whi ch operates synchronously with the exhaust ti mi ng of the engine comprises;

- at least one cylinder exhaust output (2) which has more than one cylinders, - at I east one gas return I i ne (4) whi ch carri es the exhaust gas stemmi ng from the cylinder exhaust output (2) to the intake manifold (5), and characterized by

- at least one flow control disc (8) which is connected to the cylinder exhaust output (2), whi ch is di rected to one of the cyl i nder exhaust outputs (2) accordi ng to the exhaust timing of the engine, and which enables the exhaust gas to be directed to the intake manifold (5), and which comprises moving discs (81, 83) and fixed disc (82) which move over each other.

11. An exhaust gas recirculation system (1) according to Claim 10 characterized by the flow control disc (8) which is connected to the belt pulley of the timing belt (K) using the belt pulley mounting piece (84), and which rotates circularly depending on the movement of the belt pulley (K).

12. An exhaust gas recirculation system (1) according to Claim 10 characterized by the flow control disc (8) comprising at least one first moving disc (81), at least one fixed disc (82), at least one second moving disc (83) and belt pulley mounting piece (84).

13. An exhaust gas recirculation system (1) according to Claim 10 characterized by the first moving disk (81) which can be rotated by a driving apparatus (7) as wel I as worki ng by receivi ng the drivi ng force from the engi ne ( M) via a belt or a chain.

14. An exhaust gas recirculation system (1) according to Claim 10 characterized by the fixed disc (82) which allows the flow only when the pressure of the exhaust gas is high, and additionally, which can stop the flow of the exhaust gas with the help of the second moving disc (83) at the preferred time.

15. An exhaust gas recirculation system (1) according to Claim 10 characterized by the second moving disc (83) which is located under the fixed disc (82), which enables adjusting of the flowrate of the exhaust gas and when preferred which enables stopping the flow according to its position.

16. An exhaust gas recirculation system (1) according to Claim 10 characterized by the first moving disc (81), and the second moving disc (83) which rotate around the fixed disc (82).

17. An exhaust gas recirculation system (1) according to Claim 10 characterized by the first moving disc (81) which has channels (85) on it, the second moving disc (83), and the fixed disc (82) which has a hole (86) on it.

18. An exhaust gas recirculation system (1) according to Claim 10 characterized by the flow control disc (8) which enables the flow of the exhaust gas from inside of itself according to the rotation of the moving discs (81, 83), when the channels (85) that are on the moving discs (81, 83) overlap with the hole (86) that is on the fixed disc (82).