DE3529388A1 - Intake pipe for a multi-cylinder internal combustion engine - Google Patents

Abstract

In an intake pipe for a multi-cylinder internal combustion engine with a manifold, from which one single pipe branches off for each cylinder, the single pipes being interconnected by connecting pipes in the area between the manifold and the internal combustion engine, in order to increase the power of the internal combustion engine valve devices are provided in the connecting pipes, which devices close the connecting pipes in the lower speed range of the internal combustion engine.

Description

The invention relates to an intake manifold for a multi-cylinder combustion Engine according to the preamble of claim 1.

A generic intake manifold is, for example, the Japanese one Patent abstract 54-137516 or 56-138456 removable. Are connecting pipes are provided between adjacent individual pipes, which in the higher speed range of the internal combustion engine the volume increase efficiency and thus to higher performance to contribute to the internal combustion engine. The connecting pipes should in the higher speed range, the length of the individual tubes is effective reduce.

However, it has been shown that with such an intake manifold satisfactory torque and performance behavior of the Brenn Engine is achievable, in particular there is an imbalance sufficient torque yield in the lower speed range of the internal combustion engine machine and a torque drop at medium speeds and Full load.

Such single-flow intake manifolds could not prevail to achieve high torque at low speeds (long suction paths - resonance charging) and high performance at high speeds (high gas throughput due to short suction paths). Such an intake manifold design is particularly important, however Internal combustion engines with several gas inlet valves per cylinder, because here the gas throughput in the high speed range due to the large outer inlet cross-sections is increased.

There were therefore two-flow intake manifolds with one double each cylinder  tube or two individual tubes and valve means in one each zelrohr proposed to thus in the lower speed range Fuel-air supply via a single pipe, at higher ones However, speeds over both single pipes (or the entire double tube) to be carried out (e.g. DE-PS 30 44 292, GB-A 2 010 962). Derar However, due to the inevitable jumps, suction pipes are in their cross-sectional shape is not completely satisfied with flow dynamics posed, expensive to manufacture and often result in additional control of the second cross-sectional area to uncomfortable driving behavior (Acceleration shocks).

The object of the invention is a structural and fluid dynamic to create inexpensive suction pipe of the generic type, which high torque in the lower speed range and high speed pay high performance enables, especially with internal combustion machines with several intake valves per cylinder.

This object is achieved with the features of claim 1. Contrary to the increasing trend to two-pipe suction pipes compli ornate geometry turned out to be absolutely unpredictable that with the measures according to the invention, that is, with a comparative wise little effort, excellent torque and performance behave, especially in an internal combustion engine with two on let valves, is achievable. You can start by raising the Torque in the lower speed range length and cross section of the Individual pipes are tuned so that an effective resonance charging takes place. Through the closed connecting pipes the vibration behavior of the gas flows is not disturbed.

In the upper speed range of the internal combustion engine, the Ven tilmittel in the open position, the length of the now zelrohre measured after the junction of the connecting pipes and in a simple manner on the desired performance behavior is tunable. This results in a geometrically simple intake manifold without any notable jumps in diameter.  

With a high gas throughput, the internal combustion engine is now operated via the shortened length of the individual pipes from the remaining individual pipe sections and supplied the connecting pipes, which is due to the, more favorable flow conditions a high performance even relatively small single pipe cross-sections. On the other hand, he are steeper even at low engine speeds (at full load) Torque increase and high torque values over the entire part load range; an effect like himself with double-flow, geometric complicated and complex intake manifolds is difficult to understand.

Advantageous developments of the invention are claims 2 to 4 removable, which is used to switch off a vibration partial dead volume through the connecting pipes in low rotation number range as well as good flow dynamics, especially with high gas flow rates in the intake manifold.

According to the features of claims 5 and 6, a further collection Pipe can be provided, which communicates with the connecting pipes and if necessary with the single line feeding the first manifold is bound. This can affect the performance of the internal combustion engine seem to be improved even further in the higher speed range, ins What is special is a turbulence-free, calm gas flow at high Throughput in the connecting pipes and the shortened individual pipes cuts ensured.

The valve means can be appropriate and convenient to assemble accordingly Claim 7 can be designed, the flap neck inexpensive Can be the same parts.

The control of the valve means can according to claim 8 electrically Provided a map is carried out. In doing so, each time dependent on the intake manifold pressure, on the position of the power control element and of the speed of the internal combustion engine one for the torque and performance of the internal combustion engine optimal position of the  Valve means set; the data can be in a micropro processor to be processed, which then via an output stage an electric servomotor at a predetermined adjustment curve controls. However, in a simplified control it can only be one Parameters, e.g. B. the exhaust back pressure in the exhaust pipe be drawn, the adjustment of the valve means the Ab pneumatic actuator exposed to gas back pressure.

To achieve an even fuller torque curve can be provided in further development of the invention according to claims 9 and 10, two connecting pipes or openings and a third, transverse to the individual pipes ver collecting pipe, the second and third effective single pipe length L 2 , L 3rd of the entire intake manifold.

In the partial load range, all connecting pipes are then through Valve means closed and it takes place along the entire length of the Individual pipes from the manifold to the combustion chamber inlets of the Brenn effective resonance charging instead.

At a higher speed of the internal combustion engine, the first connec tion pipes are turned on, so that a shortened individual pipe length L 2 is effective and the gas throughput through the intake pipe is increased. At even higher speeds, finally, with a further shortened single pipe length L 3, all connecting pipes are open, which, due to the even lower flow resistance in the intake pipe, ensures a relatively high torque up to the maximum speeds of the internal combustion engine.

Due to the features of claim 11, the construction of the suction tube and its weight can be reduced. Separate connection Pipes can be made in common by providing the connection openings Wall sections are eliminated.

The invention is described in more detail below on the basis of exemplary embodiments explained. The schematic drawing shows in  

Figure 1 shows an intake manifold according to the invention on a four-cylinder internal combustion engine.

Figure 2 shows an intake manifold according to the invention with a wide ren manifold on a five-cylinder internal combustion engine.

FIG. 3 shows a torque curve of an internal combustion engine having an intake manifold according to the invention;

Fig. 4 is a suction pipe in cross section with a centrally located, further manifold and two connec tion openings and

Fig. 5 shows another manifold with two additional Sam melrohren with connection openings.

A spark-ignited four-stroke internal combustion engine 10 ( FIG. 1) has four cylinders I to IV. The gas exchange per cylinder is controlled by two intake valves 12 and two exhaust valves 14 . The intake and exhaust valves are actuated in a known manner via camshafts, not shown. A suction pipe 18 is flanged to the inlet channels 16 leading into the cylinders I to IV.

The intake manifold 18 for supplying the internal combustion engine with a fuel-air mixture has four individual tubes 20, 22, 24, 26 and a manifold 28 . A flap connection piece 30 with a throttle flap 32 as a power control element is connected to the collecting pipe 28 .

The suction pipe 18 or the collecting pipe 28 is supplied with combustion air via lines (not shown) with an air filter and an air flow meter. The air flow meter is part of a fuel injection device, the injection valves 34 protrude into the individual tubes 20, 22, 24, 26 of the intake manifold 18 .

The respective adjacent individual pipes 20, 22 and 24, 26 are connected to one another by connecting pipes 36, 38 . In the connecting tubes 36, 38 are used as valve means for shutting off the connecting tube re flange-like flap piece 40 , in each of which a throttle valve 42 is rotatably mounted. On the axis of rotation of these throttle valves 42 , a lever 44 is attached, which is connected to an adjustment linkage 46 . The linkage 46 is actuated by means of an electric servomotor 48 such that the connecting pipes 36, 38 are opened or closed by the throttle valves 42 .

The length L ₁ and the cross section of the individual tubes 20, 22, 24, 26 is dimensioned such that the internal combustion engine 10 in a lower speed range of up to 5000 min ^-1 and closed connecting tubes 36, 38 emits a high torque. On the other hand, when the connecting tubes 36, 38 are effective, the length L _{2 of} the individual tubes 20, 22, 24, 26 is dimensioned such that even in the higher speed range of the internal combustion engine a high torque and accordingly a high power is output. The cross section of the connecting pipes 36, 38 is the same as the cross section of the individual pipes 20, 22, 24, 26th

The servomotor 48 is controlled by an electronic control unit 50 with an output stage. In the control unit 50 who the speed n of the internal combustion engine by means of a speed sensor 52 , by means of a pressure sensor 54 in the manifold 28 of the intake pipe pressure P downstream of the power control element 32 and by means of a sensor 56 the position α of the power control element 32 is entered. These data are processed via an integrated microprocessor in the control unit 50 with a stored characteristic map and the throttle valves 42 are adjusted via the servomotor 48 such that a high torque is present over the entire speed range of the internal combustion engine.

The torque-full-load curve shown in FIG. 3 of an internal combustion engine with the described intake manifold shows a sharp increase in section a , the internal combustion engine has reached its maximum at a speed of approximately 3000 min ⁻¹ . The connecting pipes 36, 38 are shut off by means of the throttle valves 42 . As the speed continues to increase, the torque corresponding to the curve section b begins to drop to a point c , from which, with the connecting pipes 36, 38 open , a higher torque is achieved via the curve section d . Finally, the dashed curve section e shows the torque curve with the connecting tubes always open.

The point c thus designates the point at which theoretically at full load, ie when the power control element or throttle valve 32 is open, the throttle valves 42 of the connecting pipes 36, 38 are reversed from their closed into the open position by means of the electric servomotor 48 . In practice, however, the opening of the throttle flap 42 begins before point c and only ends after point c , so that the throttle torque curve around point c is smoothed. Furthermore, a hysteresis can be provided in the reversal to exclude a constant switching of the Ventilmit tel at speeds around point c .

Torque curves, as shown in Fig. 3, can also be driven at their load conditions via the speed and the switching points are determined. At the same time, the relevant speed values, intake manifold pressures and the corresponding position of the power control element 32 are recorded and a corresponding characteristic diagram is created. After this, stored in the electronic control unit 50 , map is then controlled via the output stage of the electric servomotor 48 .

In the five-cylinder four-stroke internal combustion engine 58 shown in FIG. 2, an intake manifold 64 with five individual tubes 66, 68, 70, 72, 74 and a manifold 76 is flanged to the intake ducts 60 controlled by two intake valves 62 . From the individual pipes 66 to 74 branch connecting pipes 78, 80, 82, 84, 86 in a straight line extension, which open into a common, transverse to the individual pipes ver manifold 88 . The header pipe 88 is connected via a connecting line 90 to a single pipe section 92 , which is downstream of the power control member 94 .

Between the connecting pipes 78 to 86 and the individual pipes 66 to 74 , a flap nozzle 96 with a throttle valve 98 is used as valve means. When the throttle valves 98 are open, the individual tubes 66 to 74 are connected to one another via the manifold 88 . Furthermore, with high gas throughput in the intake manifold 64, combustion air can be drawn off directly downstream of the power control element 94 via the connecting line 90 .

The cross sections of the connecting pipes 78 to 86 are equal to the cross sections of the individual pipes 66 to 74 . The valve means or flaps 96 are close to the confluence of the connecting pipes in the individual pipes.

The control of the throttle valve 98 can in turn be as described for FIG. 1 be. Instead of the intake manifold pressure P , the combustion air throughput in the intake manifold can also be used as a parameter. In the case of an electrical fuel metering, the measured values can be taken directly from the air flow meter.

Fig. 4 shows an intake manifold 100 , which in turn is connected to a cylinder head 102 of a reciprocating piston internal combustion engine with inlet channels 104 and two inlet valves 106 per cylinder (only one inlet valve can be seen in the drawing). The individual pipes 108 with the effective length L 1 of the suction pipe 100 open into the collecting pipe 110 , which is connected to the rest of the individual pipe (with air filter, air flow meter, etc.).

The individual tubes 108 enclose a further collecting tube 112 which extends transversely to the individual tubes and which has a common wall 114 with the individual tubes 108 in the overlapping area. In this wall 114 two connecting openings 116, 118 are provided for each individual pipe 108 , which can be closed by connecting means or throttle valves 120, 122 . The connection openings 116, 118 thus define a second and third individual tube length L 2 , L 3 .

The intake manifold 100 can be formed in two parts with a parting line at the dashed line 128 to enable unimpeded assembly of the valve means 120, 122 . All throttle valves 120, 122 of the intake manifold 100 (with the exception of the power control element, not shown) are connected to one another via two shafts 124, 126 and are controlled in such a way that all the connection openings are initially closed (partial load range), then the throttle valves 122 are rotated and the connection openings 118 opened (at speeds around 4000 min ^-1 ) and finally at speeds <5000 min ^{-1 of} the internal combustion engine, the throttle valves 120 of the connection openings 116 are opened. In this case, a linkage connection with a corresponding empty gear can exist between the two shafts 124, 126, similar to register gasifiers. Otherwise, the throttle valves 120, 122 can be actuated by map control as described in FIG. 1.

In Fig. 5, the same parts with the same reference numerals are provided with Fig. 4 Chen. The intake manifold 130 shown is in turn composed of a manifold 132 and a single tube 134 with the length L 1 per cylinder of the internal combustion engine. At defined points of the individual tubes 132 , a second header tube 136 and a third collector tube 138 are arranged, each of which extends transversely to the individual tubes 134 . In each header tube 136, 138 are gene gene 140, 142 provided for each individual tube 134 , which define the effective individual tube lengths L 2 , L 3 and overlap with cross-sectional connection openings 144, 146 in the individual tubes 134 . Throttle valves 148, 150 are pivotally mounted in the connection openings 140, 142 .

The throttle valves 148, 150 can, however, also be arranged in separate valve connecting pieces, as in FIG. 1. The control of the throttle valve is carried out analogously to that described in FIG. 4. By switching on the third effective single pipe length L 3 , an even better tuning of the suction pipes according to FIG. 4 or 5 can be achieved, the torque curve of FIG. 3 being modifiable in accordance with curve section f . The switchover points result for the effective intake manifold length L 2 at point g and for the effective intake manifold length L 3 at point h . Since these switching points are dependent on the design of the internal combustion engine and the geometry of the intake manifold, the ones shown in FIG. 3 are only to be determined by way of example and empirically in a special application.

Claims (11)

1. Intake pipe for a multi-cylinder internal combustion engine, in particular for an internal combustion engine with two gas inlet valves per cylinder, with a manifold from which a single pipe branches off from each cylinder, with individual pipes in the area between the manifold and the internal combustion engine being connected to one another by connecting pipes , characterized in that the connecting pipes ( 36, 38; 78, 80, 82, 84, 86 ) by Ven tilmittel ( 40, 42; 96, 98 ) in the lower speed range of the internal combustion engine can be closed. 2. Intake pipe according to claim 1, characterized in that the valve means are arranged near the mouth of the connecting pipes in the individual pipes ( 20, 22, 24, 26; 66, 68, 70, 72, 74 ). 3. intake manifold according to claims 1 and 2, characterized ge indicates that the connecting pipes into the one cell tubes at an angle <90 °, but preferably in a straight line flow into. 4. intake manifold according to claims 1 and 2, characterized ge indicates that the cross-sections of the conn extension tubes essentially the same as the cross sections of the individual pipes are. 5. Suction pipe according to one or more of the preceding claims, characterized in that the connec tion pipes ( 78, 80, 82, 84, 86 ) in a further, transverse to the individual pipes ( 66, 68, 70, 72, 74 ) extending manifold ( 88 ) open. 6. intake manifold according to claim 5, characterized in that said further manifold is connected (88) with a first header supplying inlet conduit (92) having at least a power control element (92). 7. Intake pipe according to one or more of the preceding claims, characterized in that the valve means are throttle valves ( 42; 98 ) which are mounted in flange-like flap connections ( 40; 96 ), the flap connections being connected to the individual pipes. 8. Intake manifold according to one or more of the preceding claims, characterized in that the valve means electrically dependent on the intake manifold pressure downstream of the power control element ( 32; 94 ) and / or on the position α of the power control element and / or on the speed of the internal combustion engine are (map control). 9. Suction pipe according to one or more of the preceding claims, characterized in that the individual pipes ( 108 ) enclose the further, transverse collecting pipe ( 112 ) over a circumferential area and that in the collecting pipe ( 112 ) two each in each individual pipe ( 108 ) opening connecting pipe (connecting openings ( 116, 118 ) with valve means are provided, which define a second and a third effective single pipe length (L 2 , L 3 ) by these connecting pipes arranged offset over the circumference of the collecting pipe ( 122 ) and successively controllable are. 10. Intake pipe according to one or more of the preceding claims, characterized in that a third, transverse to the individual tubes ( 134 ) extending manifold ( 138 ) is provided, which via connecting pipes (Verbindungsöffnun gene ( 142, 146 ) and valve means with the individual pipes ( 134 ) is connected, the connecting tubes defining a third effective single tube length L 3 and the valve means of the second and third header tubes ( 136, 138 ) being able to be opened one after the other. 11. Intake pipe according to one or more of the preceding claims, characterized in that the white tere manifold ( 112 ) connects directly to the individual pipes ( 108 ) and with these in the covered area has a common wall ( 114 ) and that the connecting pipes by connection openings ( 116, 118 ) are formed in this wall ( 114 ).