DE2719683A1 - Rotary piston engine with stratified charge - has eccentric driven pump jet to give stratified injection for pilot flame - Google Patents

Abstract

The engine is of epithrocoid construction and has a fuel pump jet unit (40) receiving fuel from a low pressure source and a hydraulic booster to produce a stratified charge in the working chamber. The pump jet is a 'T' shaped housing containing a servo valve unit (70) a cylinder piston unit (72) a pump push rod (74) a flow regulator (76) and a jet nozzle (78). The boosted pressure enters via a union (60) to act on the piston cylinder unit (72). The pressure is transferred to the push rod which presses fuel from the flow regulator into the jet nozzle. The injection pressure is boosted to approximately 700 atmospheres owing to the surface differences between piston (100) and push rod (74). The pump jet is fitted adjacent to the spark plug so that the initial injection is ignited to act as a pilot flame for the main injection.

Description

CURTISS-WRIGHT CORPORATION, Wood-Ridge, N.J., U.S.A.

Rotary piston internal combustion engine with charge stratification

The invention relates to a rotary piston internal combustion engine with charge stratification, which has a housing with a multi-arched inner contour and a housing that can be rotated on the eccentric of an eccentric shaft Has piston, which together delimit working chambers, the volume of which changes when the piston rotates, with im Housing air inlet and exhaust gas outlet openings, at least one Injection nozzle supplied by a fuel pump for injecting fuel into at least partially compressed air and a Spark plug are provided near the injector.

It is known that the harmful constituents in the exhaust gas of internal combustion engines are considerably reduced by charge stratification can be. This is understood to mean a system in which the fuel-air mixture in the combustion chamber is not the usual homogeneous fuel-rich or stoichiometric mixture of fuel and air, but an inhomogeneous mixture with at least one zone in which a fuel-rich or stoichiometric Mixture is present, the ignition of which causes the ignition of fuel in zones with a relatively poor fuel-air mixture. In Known rotary piston internal combustion engines with charge stratification (see, for example, US Pat. No. 3,894,518) have two fuel injection nozzles and two separate high pressure fuel pumps are required. There fuel nozzles and volumetric fuel injection pumps are expensive, these charge stratification systems are not costly with conventional fuel systems

709849/0719

competitive. In addition, there is a precise regulation of the fuel injection more difficult to achieve because such fuel injection pumps (see also, for example, US Pat. No. 2,565,685) below high mechanical shock effects, uncontrolled dynamic processes, fluctuations in delivery from cycle to cycle, post-injection and other disadvantages. It is therefore difficult to obtain accurate amounts of fuel using such fuel injection pumps and pressures when supplying fuel to one injector to achieve a pilot flame and to the other The injection nozzle must be precisely adhered to over the entire working range of the machine in accordance with the speed and the load.

It is desirable to ignite the main amount of fuel by means of a pilot flame, as this ignition method ensures reliable ignition by means of a spark plug alone is not achieved at every load and speed.

Accordingly, the invention is based on the object of a charge layer system for rotary piston internal combustion engines that have a high-pressure pilot and a high-pressure main fuel injection made possible by means of a single low-pressure fuel pump, and is therefore relatively cheap.

The charge stratification system according to the invention is characterized in that that the injection nozzle as a pump nozzle with hydraulic Reinforcement is formed, and that a fuel control system is provided for regulating the fuel supply to the pump nozzle is to this at a certain eccentric shaft rotation angle a small amount of fuel for ignition by the spark plug and Generation of a pilot flame and on it the same and / or a second pump nozzle one of the speed and load of the internal combustion engine to supply the appropriate amount of fuel that is ignited by the pilot flame.

709849/0719

The fuel control system has a delivery line from one Fuel source to the or each pump nozzle, a return line from the pump nozzle to the fuel source and an accumulator in the delivery line. A low-pressure pump is arranged in the delivery line, the delivery side of which is connected to the reservoir is to supply this fuel under pressure. In addition, means are provided which are in accordance with the position of the Eccentric shaft supplies fuel from the accumulator through the delivery line to the or each pump nozzle. In the reflux line can a throttle valve responsive to engine speed to reduce that injected by the pump nozzle (s) Control fuel amount.

Two embodiments of the invention are described below with reference to the drawings. It shows:

1 shows a cross section through a rotary piston internal combustion engine in trochoid design in schematic representation,

2 shows a schematic representation of the entire fuel injection system according to the invention,

3 shows a longitudinal section of a pump nozzle with hydraulic Reinforcement, which is used in the injection system according to FIG. 2,

Fig. 4 is a longitudinal section of a distributor in the Injection system of Fig. 2 is used,

Fig. 5 is a cross section of a throttle device with variable Cross section used in the injection system of Fig. 2,

6 shows a cross section similar to FIG. 1 of a rotary piston internal combustion engine in trochoid design with a modified injection system, and

709549/0719. 4th

7 is a diagram showing three different forms of fuel injection shows that can be achieved by setting the injection system accordingly.

Reference is first made to FIGS. 1 and 2, in which 10 generally indicates an injection system for a rotary piston internal combustion engine 12 of the trochoid type is designated.

As shown in FIG. 1, the rotary piston internal combustion engine 12 has a housing with side parts 14 and a jacket 16, the inner surface 18 of which has the shape of a two-arched epitrochoid. The housing encloses a working space 20 in which a piston 22 is rotatably mounted on the eccentric 24 of an eccentric shaft 26. The piston 22 has three piston flanks 28 which form three corners 30. With the housing, the piston 22 delimits three working chambers A, B, C, which successively increase their volume and then decrease it again when the piston 22 rotates like a planet within the working space 20. The piston 22 has at its corners 30 sealing strips 32 and on one end face 34, not shown, axial seals, by which the working chambers A, B, C are separated from each other A occurs. Furthermore, the jacket 16 has an outlet channel through which the burnt gases are pushed out of the working chamber which is pushing out (in FIG. 1 working chamber C). In order to supply fuel to the working chamber B, the injection system 10 is provided.

This system is shown in full in FIG. 2, and it has a pump nozzle 40 with hydraulic amplification, which is carried out by a fuel delivery line 42 with a source of fuel, for example a tank 44, is connected to receive fuel via a low pressure pump 46 and an accumulator 48. The pump nozzle 4o is arranged in the jacket 16 in order to inject fuel into the working chamber B. The pump nozzle 40 is also provided with a Return line 50 connected to return excess fuel to reservoir 44. In the return line 50 is one Throttle device 5> 2 with variable passage cross-section

709849/0719 ₅

provided, which depends on the machine 2719683 speed controlled and connected for this purpose with a centrifugal regulator 54 or other device which is responsive to the speed of the eccentric shaft 26. A distributor 56 is via a line 58 to the memory 48 and connected via a line 60 to the pump nozzle 40 in order to supply the latter with fuel under pressure. Excess fuel can flow back from the manifold 56 via a line 62 and the return line 50 to the container 44. On the line 62 a check valve 64 is provided, which prevents fuel from the return line 50 through the line 62 can flow to the distributor 56. In the jacket 16 of the machine housing, a spark plug 66 is arranged, which is from the pump nozzle 4o injected fuel ignites. As will be described later, the spark plug 66 does not serve the whole To ignite fuel, which is injected into the working chamber B depending on the speed and load of the engine. Of the Drive or control of the pump 46, the variable throttle device 5? and the distributor 56 is carried out by corresponding Connection to the eccentric shaft 26. This connection is indicated schematically by the dashed line 68.

In Fig. 3, a pump nozzle 4o is shown which is able to To supply fuel to the working chambers in a controlled amount and with the necessary pressure. The pump nozzle 40 has a substantially T-shaped housing, which has a servo valve sub-unit 70, a cylinder-piston sub-unit 72, a pump tappet 74, an inflow valve 76 and a nozzle subassembly 78 receives. the Control valve subassembly 70 includes a spool 80 that is reciprocable in a bore and two sections 82 and 84 for controlling the flow of fuel into and out of the The cylinder-piston sub-unit 72 has an inlet duct 86 and an outlet duct 88. The inlet channel 86 is in communication with the fuel supply line 42, in which the fuel is held by the memory 48 at an increased pressure, for example 70 Atu. The valve body 80 is closed by a spring pressed to the left in FIG. 3 in order to shut off the inlet channel 86.

709949/0719

A plunger 92 acts on the end of the remote from the spring 90 Valve body 8o to the valve body 8o under the action of the pressure of the fuel from the distributor 56 via the line 60 is fed to one end of the plunger 92 to bring it into an open position. This fuel, which is under the pressure in the The accumulator 48, that is to say, for example, is under a pressure of 70 atmospheres, is fed to the plunger 92 via a throttle point 94. When the grooves 96 in the section 84 the cylinder 98 of the cylinder piston subassembly 72 connect to the inlet channel 86, fuel flows into the cylinder 98 in order to reach the piston 100 of the cylinder-piston subassembly 72 to exert a lot of pressure. This pressure on the piston 100 pushes the plunger 74 downwards, which in turn Forces fuel into and through the nozzle subassembly 78 through passages 102. The injection pressure is extraordinary high due to the area ratios of piston 100 and plunger 74. If piston 100 has an effective area that is ten times that of the tappet 74 and when the fuel pressure in the cylinder 98 is 70 AtU, the pressure exerted on the fuel by the plunger 74 is 700 AtU. The jet needle lo4 of the nozzle subassembly 78 is controlled by the pressure in the Fuel supply line 42, which via the inlet channel 86, the channel I06 and another channel, not shown, with the space is connected above the nozzle needle 104, acted upon in the closing direction. The channel I06 is arranged in the housing and connects the inflow valve 76 with the inlet channel 86. When the fuel flow to the plunger 92 via the line 60 through the manifold 56 is shut off, the spring 90 moves the piston valve 80 to the left in FIG. 3, so that the inlet channel 86 is shut off and the grooves in section 82 connect cylinder 98 to exhaust port 88. In this position, the piston 100 is due of the higher pressure at the lower end of the plunger 74 moves upwards. This creates a pressure drop across the inflow valve 76, thereby opening it and allowing fuel from the inlet port through port I06 into ports 102 and to the lower end of the

- 7 709849/0719

Can flow bore in which the plunger 74 is arranged. Any leakage of fuel within the pump nozzle 4o is passed through channels (not shown) to the return flow connection 107 for the purpose of recirculation supplied to fuel tank 44 via line 50.

According to the first exemplary embodiment of the invention, at least one of the grooves 96 in the piston slide section 84 is longer than that other or designed differently to an initial connection of the intake port 86 with the cylinder 98 and thereby an initial injection through the nozzle subassembly 78. This initial injection takes place with the ignition by the spark plug 66 coordinated to ignite the fuel and create a pilot flame in working chamber B.

As shown in FIG. 4, the manifold 56 has a housing I08 a bore 110 in which a rotary valve 112 is arranged. The rotary valve 112 has an extension 114 with which it is connected to a drive shaft, for example the eccentric shaft 26. The housing 1O8 has an inlet passage 116, which with the Line 58 is connected and receives fuel from this. A Outlet passage 118 in housing I08 is connected to conduit 60 to intermittently deliver fuel to plunger 92 of the servo control valve subassembly 70 feed. A return channel 120 is connected to the pump nozzle 4o by means of a line 122 in order to Receiving fuel and through lines 62 and 50 in the Fuel tank 44 returned. The rotary valve 112 has in its outer surface a longitudinal groove 124 which is dimensioned so that it can connect the inlet channel 116 to the outlet channel II8 and thus, when the rotary valve 112 is rotated, underfoot intermittently supplies high pressure to the plunger 92 and thus causes an intermittent displacement movement of the piston valve 80. The rotary valve 112 is also provided with a bore 126 which the return flow channel 120 intermittently with a Outlet port 128 connects from which line 62 extends.

709849/0719

The throttle device 52 (FIG. 5) has a housing I30 with a bore 134 in which a cylindrical rotary valve 132 is arranged. The rotary valve I32 has a cross hole I36, which in the open position of the throttle device in connection with an inlet channel 138 and an outlet channel I4o in the housing I30 stands. An inlet port 142 connects the inlet port I38 with one part of the return flow line 50, while an outlet connection 144 connects the outlet channel 14o with the other part of the return flow line 50 connects. At one end of the rotary valve I32 is a lever 146 attached, which in turn is connected to the controller 54, a rotation of the rotary valve I32 and a movement of the transverse bore 136 relative to inlet and outlet ports I38 and I4o and thus to effect a change in the passage cross section as a function of the speed of the eccentric shaft 26. This change in cross-section through the throttle 52 serves to reduce the amount of return flow from the pump nozzle 4o through the return line 50 and thus changing the injection quantity.

The memory 48 shown schematically in Fig. 2 has a flexible partition wall 148, a gas chamber 150 and a Fuel chamber I52 separates from each other. The gas chamber I50 will with compressed gas, for example air or nitrogen, with a pressure that is slightly lower than the fuel pressure, for example 70 atmospheres is acted upon. When the internal combustion engine is started and the pump 46 begins to deliver, the partition wall 148 in FIG Deformed towards the gas chamber I50. When the distributor 56 the fuel chamber I52 of the accumulator 48 with the line 60 connects to move the piston valve 80 and the delivery line 42 via the inlet channel 86 in communication with the cylinder 98 to bring the cylinder-piston sub-unit 72, the intermediate wall 148 deforms rapidly towards the fuel chamber 152, whereby Fuel is supplied to the pump nozzle 4o.

After the internal combustion engine has started, the distributor 56 operates fuel injection through nozzle subassembly 78 in FIG the working chamber B. As can be seen from Fig. 3, at the beginning of the movement of the piston valve 80 due to the (at least

709849/0719 _ _g _

Al

a) longer groove 96 in section 84 causes a first flow of fuel into cylinder 98. This initial fuel flow displaces the piston 100, which in turn effects an initial injection of fuel through the nozzle subunit 78 into the working chamber B. Simultaneously with this fuel injection, the spark plug 66 is activated in order to ignite the fuel and to generate a pilot flame in the working chamber B. As the piston slide 80 continues to move, the inlet passage 86 is brought into full communication with the cylinder 98, thereby moving the piston 100 by an amount determined by the speed and the load on the engine. This later fuel injection phase can be viewed as the main injection phase. The fuel of this main injection phase is not ignited by the spark plug 66, but by the pilot flame that was generated by the initial injection. The duration of this main injection phase and thus the amount of fuel injected is controlled by the variable throttle 52, specifically as a function of the speed of the eccentric shaft 26. For each working chamber A, B, C, the process described above is repeated when the piston J52 the has reached the relevant position relative to the nozzle sub-unit 78 of the pump nozzle 40.

In Fig. 7, there are three fuel injection graphs with different ones Pilot injection quantities P and main injection quantities H shown for a specific engine and for a specific one Load and speed can be achieved by changing one or more of the following factors:

a) Change in fuel pressure in accumulator 48

b) Changing the shape of one or more grooves 96 in the section 84 of the spool valve 80, making the pilot fuel injection phase is changed,

709849/0719

c) Changing the cross-sectional areas of the inlet and outlet channels I38 and 140 and the cross-bore 1J> 6 of the variable throttle 5 ² in order to change the flow cross-section of the throttle and thus the return speed of the servo control valve subassembly 70.

In FIG. 6, a charge stratification system I60 is corresponding to one Second exemplary embodiment of the invention is shown, which basically differs from the charge layer system 10 of FIG only differs in that, instead of the one pump nozzle 4o, two pump nozzles are arranged in the internal combustion engine 162.

In view of the great similarity of the two charge layer systems 10 and I60 and the rotary piston internal combustion engines 12 and 162, are the parts of the charge stratification system I60 and the internal combustion engine 162 are denoted by the same reference numerals.

As shown in Figure 6, the charge stratification system includes two pump nozzles 164 and 166, each structurally the same of the pump nozzle 4o, which is shown in detail in Fig. 3, with the exception that the servo control valve subassembly 70 each of the two pump nozzles 164 and 166 is modified so that the pump nozzle 164, which is assigned to the spark plug 66, only injects the fuel necessary to generate a pilot flame, while the pump nozzle I66 injects fuel into the working chamber B is injected in the amount that is necessary for a specific engine speed and load, i.e. the main fuel injection causes. In order to coordinate the action of the pump nozzles 164 and 166, the manifold 168 is modified by arrangement a second (not shown) set of outlet and return channels 118 and 120, which is provided with a second longitudinal groove 124, which is shown in dashed lines in Fig. 4, cooperates in the rotary valve 112, so that the servo control valve subunits

- 11 -

709B49 / 0719

of the two pump nozzles 164 and 166 are actuated one after the other and in relation to the rotation of the eccentric shaft 26. For the supply and return of fuel to and from the pump nozzles 164 and 166, the supply line 42 and the return line are used 50 connected to branches 170 and 172, respectively, from which lines 174, I76 and I78, I80 to the pump nozzles 164 and 166 lead. Alternatively, junction 172 could be omitted and each return branch line I78 and I80 directly to the variable Throttle 52 are connected, which then also as a junction would work. This double connection of the variable throttle 52 is shown in Fig. 5 by a second, in dashed lines Connection 182 shown is indicated.

The mode of operation of the charge stratification system I60 is same as that of the system 10. The only difference is that the pump nozzle 164 serves only perform the pilot fuel injection while the pump nozzle 166 is performing the main injection.

Without departing from the scope of the invention, more than one pump nozzle 166 could also be provided for the main injection. In addition, the pump nozzles 164 and I66 or the (single) Pump nozzle 40 can be provided at a different point in jacket 16 and / or in side parts 14. Also need the items the pump nozzles are not arranged in a common housing.

The illustrated and described charge stratification method for a four-stroke rotary piston internal combustion engine of the trochoid type enables extremely accurate fuel injection in accordance with engine speed and load, as well as a reliable ignition of the fuel, so that the fuel consumption is improved and the harmful constituents

709849/0719

parts in the exhaust gas are considerably reduced. The inventive Charge stratification system can be used in terms of injection quantity and timing for a specific rotary piston internal combustion engine the trochoid design can be optimized. Furthermore, it is a Binspritzsystem, which is only one Fuel feed pump required for a plurality of injection nozzles or processes.

- patent claims -

709849/0719

/ ff

Blank page

Claims (1)

Patent claims 1. Rotary-piston internal combustion engine with a stratified charge, the "^ has a housing with mehrbogiger Tnnenkontur and a rotatable on the eccentric of an eccentric shaft piston, which together define working chambers, the volume change upon rotation of the piston, wherein the housing air inlet and exhaust Outlet openings, at least one injection nozzle for injecting fuel into at least partially compressed air and a spark plug are provided near the injection nozzle, characterized in that the injection nozzle is designed as a pump nozzle (40) with hydraulic amplification and that a fuel control system (10) for the regulation of the fuel supply to the pump nozzle (4o) is provided that the pump nozzle (4o) at a certain eccentric shaft rotation angle a small amount of fuel for ignition by the spark plug (66) and generation of a pilot flame and the same and / or a second pump nozzle (166 ) one of the speed and the load on the internal combustion engine Schine supplies the appropriate amount of fuel, which is ignited by the pilot flame. 2. Rotary piston internal combustion engine according to claim 1, characterized in that the pump nozzle (40) is a piston-cylinder sub-unit (72), the piston (100) of which can be acted upon by the fuel delivered by a fuel pump (46) is and acts on a plunger (74), the area of which is significantly smaller than the area of the piston (100) and which applies high pressure to the fuel to be injected. 709849/0719 0RI6INAL INSPECTED 5. Rotary piston internal combustion engine according to claim 1, characterized characterized in that the fuel control system has a fuel supply line (42) for connecting a fuel source (44) with the or with the pump nozzles (40 or 166) that the Pump nozzle (s) through a return line (50) to the fuel source (44) are connected that in the inflow line (42) a memory (48) is arranged and a pump (46) whose The delivery side is connected to the accumulator (48) in order to supply the latter with fuel under pressure, depending on the eccentric shaft rotation angle effective control means (56) the flow of fuel from the accumulator (48) to the pump nozzle (4o) or the pump nozzles (164, 166) are provided, and that the return line (50) has a throttle (52) whose Cross-section depending on the speed of the eccentric shaft (26) is variable in order to control the injection quantity. 4. Rotary piston internal combustion engine according to claim 1, characterized in that several pump nozzles (164, 166) in one Are arranged at a distance from one another in the housing of the internal combustion engine and a pump nozzle (164) in the immediate vicinity the spark plug (66) is provided, and that the fuel control system is designed so that it is in the immediate Near the spark plug (66) arranged pump nozzle (164) for generating a pilot flame and then the or the supplies other pump nozzles (166) with an amount of fuel corresponding to the speed and load of the internal combustion engine, which is ignited by the pilot flame. 5. Rotary piston internal combustion engine according to claim 4, characterized in that the pump nozzle (4o) is a piston-cylinder sub-unit (72), and the fuel control system (10) - 15 - 709849/0719 a pump (46) containing a portion of the fuel from a fuel source (44) under pressure from the pump nozzle (40) to act on the piston (74) of the piston-cylinder sub-unit (72), and another part of the Fuel to be injected through the pump nozzle (4o) into the working chamber (B) due to the action of the Piston (74). April 29, 1977
Sp / bä 709849/0719