NO143816B - COMBUSTION ENGINE, SPECIAL DIESEL ENGINE WITH EXHAUST GAS SHOPS - Google Patents

Description

The invention relates to an internal combustion engine, in particular a diesel engine, with an exhaust gas turbocharger and with a diversion channel for the charge air to the exhaust channel in front of the turbine as well as the diversion channel arranged throttling means with a continuously variable flow cross-section, which throttling means provide a pressure difference between the outlet of the compressor and the inlet of the turbine.

From DT-OS 2 120 687, a bypass line is known for the direct continuous flow of fresh air delivered from the compressor to the exhaust gases from the engine. A combustion chamber is arranged in front of the turbine. The combustion chamber is fed with the exhaust gas and the fresh air supplied through the bypass line.

From the German patent document 693277 it is known to regulate the charging pressure in internal combustion engines by means of a control valve. This valve is regulated manually or depending on operating values, for example the fuel supply, or the flight height in the case of airplanes.

In DT-OS 1 451 910, an internal combustion engine is shown with an exhaust gas turbo line, where non-return valves are arranged in a diversion.

From the Swiss patent document 508 127 it is

known an air supply device for an internal combustion engine, where a bypass line contains a valve for separating the inlet and outlet line. The valve is operated manually or automatically and is kept open as long as fuel is supplied.

From US patent 2,654,991, a supercharged engine with a bypass is known. An automatically controlled throttle is provided. The throttle includes an air-balanced valve whose angular position is controlled by the pressure prevailing at the compressor outlet. The valve is thus not controlled by the pressure on the upstream and downstream side.

From Swedish patent 343 9 20, a supercharged engine with a bypass is known. In the passage there is a valve. The valve remains open only as long as fuel is supplied to the injection nozzle. It is thus an on-off valve that is not intended to provide a pressure difference.

The task that forms the basis of the present invention is to retain the advantages associated with a diversion channel which is constantly open during operation and suitable for the transfer of the entire amount of air not occupied by the combustion engine, and at the same time above all to provide a flushing. In addition, the thrust of the combustion gas from the cylinders must also be reduced, whereby the engine's efficiency can be increased.

According to the invention, this is achieved by the fact that the throat means are in the main case exclusively controlled by the pressures that prevail in front of and behind the throat, as an increase in the pressure behind the throat results in a reduction of the passage cross-section of the throat and an increase in the pressure in front of the throat causes a

increasing the passage cross-section of the throat, so that the pressure difference provided by the throat means changes in the same direction as the pressure in the diversion channel in front of the throat.

The fact that the control of the flow cross-section

is mainly only caused by the pressures in front of and behind the throat, means that the provided pressure difference will be independent of the amount of air that flows through the throat. In the event of a change in the amount of air, the flow cross-section will automatically adjust itself in such a way under the influence of the pressures that the corresponding pressure difference is maintained. At a certain pressure in front of the throttling point, the pressure difference achieved as a result of the throttling will therefore remain constant, even when the speed of the engine and thus the amount of air taken up changes significantly, which leads to significant changes in the amount of air flowing through the diversion channel.

On the other hand, for the sake of the plant's optimal operation, it is of great importance that the pressure difference provided by the throttling means changes in the same direction as the pressure in the diversion channel in front of the throttling point, i.e. that the thick-difference should rise with rising pre-compression pressure and should fall with falling pre-compression pressure . Appropriately, the change in the pressure difference is a linear or substantially linear function of the change in the precompression pressure, i.e. the pressure in front of the throttle.

The consequence of this is that the ratio between the turbocompressor's compression ratio and the turbine's relaxation ratio remains constant. This means that the required drive energy for the turbine at all times is achieved with the lowest possible gas temperature. A further consequence of the change in the pressure difference depending on the pre-compression pressure is that you get the best flushing conditions for the cylinders in the engine.

The control of the throttling means in the diversion channel mainly only by means of the prevailing pressures in front of and behind the throttling point represents a feature whose advantage has been explained above. What is new in this context is such a control of the throttle that the pressure difference provided by the throttle changes in the same direction as the pre-compression pressure prevailing in front of the throttle. What is also new is the application of this throttling in a diverting channel that is constantly open during operation, which enables the compressor to work close to its pump line.

As the transport work for the exhaust gases is reduced, the effective mean pressure is obviously increased as a value that corresponds to differences between the pressure in front of the choke means and behind the choke means.

Furthermore, the engine can be allowed to work with high pre-compression pressures, as the compressor works close to the pumping limit.

According to an advantageous embodiment of the invention, the throat means contain an arranged in the diversion channel, with a fixed seat cooperating throat organ.

This throat organ or throat valve body can be firmly connected to an equalizing piston which is affected by the pressure that prevails in the diversion channel before or behind the throat. Advantageously, elastic means can be used which keep the throat open.

Further features of the invention will emerge from the claims and the advantages will be elucidated in more detail in connection with the discussion of preferred embodiments of the invention.

According to a special device according to the invention, which can be used in cases where there is a combustion chamber which receives a supply of fresh air through a primary inlet which supplies fresh air to a combustion chamber, as well as an inlet for secondary air for the introduction of fresh air into a mixing chamber, the aforementioned throat means comprise , in parallel, a first throttle member with variable flow cross-section arranged so that the throttle is passed through by secondary air and which first throttle induces, between the front part of the bypass duct (the part connected to the compressor) and the rear part of the bypass duct (the part connected with the combustion chamber), a pressure difference which is a rising function (preferably linear or substantially linear) of the pressure prevailing in the front part of the channel, and a second throat member with a variable flow cross-section which is exposed to the pressure difference created by the first throat member and is arranged so that the second pass through the larynx s of primary air and regulates the supply of primary air as this throttle produces a flow cross-section for the primary air which is flushed by the pressure that prevails in the rear or front part of said diversion channel, which control follows a specific law.

Preferably, said second throttle device controls, among other things, a regulation device for the fuel supply to the combustion chamber so that a ratio is achieved for primary air and fuel which ensures good combustion stability.

It will thus be understood that a relationship is maintained between the flow cross-section S ps which is open to the primary air, and the flow cross-section Ss which is passed through by the secondary air.

If ^p denotes the pressure difference on both sides of said first laryngeal organ, and P denotes the pressure that prevails in the front part of the diversion channel, one can write the linear growth function that connects AP and P in the following way:

where et and 8 are two coefficients.

Furthermore, one has that this pressure difference A<p> is proportional to the specific weight m of the fresh air and the square of its velocity V:

where k is a first approximation constant.

From the two equations above, one can then derive the expression for the speed V:

The sum of the duct cross-sections S p and S s is linked to the total supply Q of fresh air in the diversion duct, according to the following equation:

where S is a function of P, i.e. S = f (P), where F (P) expresses

P. P

the specific law that connects the cross-section S^ with the pressure P, and one can then eliminate the velocity by replacing this with the pressure function:

Under these conditions, the primary air supply Qp will only depend on the pressure P, according to the equation:

The supply of secondary air QQ is always equal to the difference between the total supply flowing through the diversion channel and the supply of primary air Qp.

According to a favorable embodiment according to the invention, said first throat means consists of a movable set which encloses on one side of said second throat means and also the regulation device for fuel supply....

The movable set which forms said first throat can thus consist of a cylinder which is externally provided with a throat member which cooperates with a fixed seat, the second throat then consisting of one or more openings taken out in this cylinder, as well as a rod that covers or uncovers this or these openings, which rod is driven by a piston where one side is exposed to the pressure in the rear or front part of the diversion channel, and the other piston side takes up a counter pressure and a spring pressure, and so that the rod or piston is preferably connected to regulating bodies for fuel supply.

The invention will be understood more easily in connection with the following description which is linked to the attached drawings which are not to be understood as limiting, but describe preferred embodiments of the invention, and where: Fig. 1 schematically shows a supercharged diesel engine equipped with a combustion chamber which has a single fresh air - intake, and otherwise equipped according to the invention. Fig. 2 schematically shows a supercharged diesel engine provided with a combustion chamber with two fresh air inlets, and constructed according to an embodiment of the invention where the combustion chamber is provided with a "return" injector. Fig. 3 schematically shows a supercharged diesel engine equipped with a combustion chamber with two fresh air supplies and constructed according to an embodiment of the invention, where the combustion chamber is equipped with a "non-return" injector. Fig. 4 shows a part of an important part of the engine in fig. 2, which illustrates a variant of the invention. Fig. 5 reproduces a curve relating to the operation of the motor according to the invention.

The diesel engine shown in fig. 1 has the reference number 101 and is supercharged with a turbo compressor group with the reference number 102.

The turbo compressor group 102 consists of a compressor 10 3 which supplies compressed air for supply to the engine through a supply line, and a turbine 104 which drives said compressor 103 via a shaft 105, the turbine 104 itself being driven by means of the exhaust gas from the engine 101.

A circulation channel 106 is arranged which ensures a direct and permanent supply of fresh air from the compressor 103 to the exhaust gas from the engine.

Preferably, a combustion chamber 107 is arranged in front of the turbine 104, where the combustion chamber 104 receives a supply of exhaust gas and fresh air that is diverted through the discharge channel 106.

According to the invention, there are arranged throttle bodies 108 with variable recirculation cross-section, arranged so that the throttle body is passed through by air diverted through the bypass channel 106, the throttle body 108 providing, between the front part of the diversion channel 106 (the part connected to the compressor 103) and the rear part of the diversion 106 (the part connected to the turbine 10 4 via the combustion chamber 107) a pressure difference P which is an increasing function, preferably linear or substantially linear, of the pressure prevailing in the front part. This linear function can be written:

where a<1> and 3' denote two coefficients.

According to a first embodiment which is shown in 1 fig. 1, the throat member 108 consists of a throat member 108a placed in the diversion channel 106 in accordance with a fixed seat 108e.

The throttle 108a may be carried by a rod or shaft 108b, one end of which is connected to a balance or equalizing piston 108c which slides in a cylinder, or better 'connected to the diversion channel 106 through a deformable wall 108d.

The diameter of the throttle 108a and the diameter of the piston 108c are adjusted so that the throttle body 108a is in equilibrium,

' of the pressure P acting on the front part and the inner surface of the piston 108c,

of the pressure P - Ap acting against the rear,

and of the atmospheric pressure acting on the outside of the piston 108c.

Spring organs can also act on the throat organ 10 8a to determine the coefficient 3' according to the law Ap = a'p + 8'.

These spring means can consist of a spring 109 and/or of the inherent elasticity of the deformable wall 108d.

In order to be able to vary the coefficient 6', one can use regulating devices with which one can adjust the resultant force acting on the throat organ 108a by means of elastic systems, these regulating devices can consist of a nut 110 which changes the tension on the spring.

This device is particularly interesting because the pressure difference created by the throttle body 108 can then be adapted to the installation of which the supercharged engine is a part. In particular, the pressure difference can be adapted to the pressure drop that occurs through a filter device 111 located at the entrance to the compressor 10 3 and/or the pressure drop through a noise pot 112 at the exit from the turbine 104.

A viscous damping member, which is described in more detail below, can advantageously act on the throat member 108a to absorb vibrations of aerodynamic origin to which the throat member 108a is exposed. This viscous damper works advantageously on the basis of a viscous liquid that is under variable pressure.

A device will be described more specifically below

according to the invention which relates to the case where the combustion chamber receives fresh air supply through a primary air intake for the introduction of fresh air to the combustion chamber and the supply of secondary air for the introduction of fresh air to a mixing chamber.

Reference is made to fig. 2 illustrating a diesel engine having the reference number 1, the engine is supercharged from a turbocharger with the reference number 2.

The turbo compressor group 2 comprises a compressor 3

which supplies compressed air to the engine through the line 4, and a turbine 5 which drives the compressor 3 via the shaft 6, this turbine 5 is itself driven by the exhaust gas from the engine 1.

A diversion channel 7 is arranged which causes direct and permanent passage of fresh air supplied by the compressor 3 to the exhaust gas from the engine.

A combustion chamber 8 is arranged in front of the turbine 5, the combustion chamber 8 receives a supply of exhaust gas through a line 9 and of fresh air diverted through the line 7.

The combustion chamber 8 receives a further supply of fuel through the injector 10 fed from the pump 11 which sucks from a reservoir 12.

As regards the supply to the combustion chamber 8 of exhaust gas and fresh air, a system is used after which the combustion chamber is supplied.

through an intake channel for fresh air 13 for introducing fresh air into the combustion chamber 14,

through an intake of exhaust gas 15 for the introduction of exhaust gas to a mixing chamber 16 located after the combustion chamber 14,

and through an intake for secondary air 17 for the introduction of fresh air at the level of said mixing chamber 16.

The intake for fresh air 13 can consist of a central channel 18 arranged coaxially in the combustion chamber 8, the intake for exhaust gas can then be constituted by a first ring-shaped channel or line 19 which surrounds said central channel 18, and finally the intake for secondary air 17 can consist of a second annular channel 20 surrounding the first annular channel 19.

According to the invention, it is arranged:

first throat member 21 with variable flow cross-section, arranged in such a way that secondary air flows through, this first throat 21 forming, between the front part of the diversion channel 7 (the part connected to the compressor 3) and the rear part of the diversion channel (the part which is connected to the combustion chamber 8) a pressure difference Ap which is a rising function, preferably linear or essentially linear, of the pressure P which prevails in the front part,

and a second throat member 22 with variable flow-1 cross-section which is exposed to the pressure difference AP which is created by said first throat member 21 and which is flowed through by primary air, where said second throat member 22 has a normal flow cross-section for primary air which is adapted to the pressure P - Åp which prevails in the rear part of the diversion channel 7, as this adaptation or control follows a specific law.

Advantageously, the second throat organ 22 also controls a control device for the supply of fuel 2 3 and regulates the amount of fuel injected into the combustion

-LU

the chamber 8 so that a ratio between the supply of primary air and fuel is achieved which provides good combustion stability, i.e. a ratio which is as close as possible to the stoichiometric ratio.

It will thus be seen that the fresh air which is diverted to the diversion duct 7 is divided into: primary air which is branched off to the primary air intake 13 and said second throttle 22 for supply to the combustion zone 14 in the combustion chamber 8, and secondary air which is branched off to the secondary air intake 17 and first throttle 21 for supply to the mixing zone 16 in the combustion chamber 8.

The delivery of air flowing in the bypass duct 7 varies within a ratio of 1 to 10 according to whether the engine is operating during normal operation or the engine is operating during slow operation (combustion chamber pulled out maximum).

In contrast, the supply of fuel required for the operation of the combustion chamber 8 will be self-evidently enabled by the turbo compressor group 2 at the start of the engine, and sufficient fuel supply to maintain the operation of the combustion chamber 8 during normal operation (an idle time) has a ratio of about 30:1.

The stability of the combustion in the combustion chamber is optimal if the supply of pre-combustion air, i.e. the supply of air branched off to the primary air intake is close to the amount required for stoichiometric ratio.

As explained above, the sum of the cross-sections S^ + Sg of the flow channels (which are respectively available for the flow of primary air and secondary air) is thus determined by the values for the compressor back pressure P and by the supply Q of fresh air to the diversion channel 7. Under these conditions and for the organization of the supply of fresh air and secondary air, it is sufficient to regulate one of these secondary flow openings, while the other is adjusted through the difference, consequently regulating the flow channel S^ which is open to primary air.

As regards the aforementioned specific law which is followed between, on the one hand, the flow cross-section S for primary air and, on the other hand, the back pressure P - Ap which prevails in the rear part of the diversion channel 7, this can be chosen so that one takes into account the operation of the combustion chamber together with the entire engine-turbocharger group. One will later come back to this law in more detail after two embodiments of the invention have been described below, where the first concerns a supply to the combustion chamber through an injector of the "return" injector type (fig. 2), and where the second concerns means a supply to the combustion chamber through an injector of the "non-return" type (see fig. 3).

According to a particularly simple embodiment of the invention

with regard to construction, and which can give rise to two designs, resp. illustrated in fig. 2 and 3, said first throat member 21 consists of a movable set that encloses said second throat member 22 as well as the regulation system for the supply of fuel 23.

Thus, the movable system in the form of the first throat 21 can consist of a cylinder 24 which externally has a throat member 25 in cooperation with a fixed seat 26. Under these conditions, said second throat member 22 can consist of one or more openings 27 which is taken out in the cylinder 24 with a rod 28 covering or uncovering the hole or holes 27 in such a way that the shaft or rod 28 forms a piston where one of the piston sides is exposed to the pressure from the primary air and the other piston side is exposed to the counter pressure Pc and for the pressure from the spring 29, so that the rod 28 is connected to the fuel supply regulator 23.

) Opening or covering the hole or holes 27 of the shaft 28 which makes up the piston rod can be done by providing the piston with one or more openings 28a which are taken out in the piston skirt 28b.

When it comes to the counter pressure against the piston rod

> 28 this can be equal to atmospheric pressure. In certain cases, and in order to shift the regulation range, you can choose a back pressure Pc that is higher than atmospheric pressure, it is then particularly easy

to arrange a regulation chamber 30 which is in connection with

the relevant side of the rod 28 and is likewise in connection with atmospheric pressure via the throttle opening 31, where the regulation chamber receives a supply of compressed air through a flexible line 32. This compressed air permanently exits the regulation chamber 30 through the throat opening 31 and creates an overpressure in the regulation chamber 30 which then the back pressure forms Pc.

For this purpose, it is particularly advantageous to connect the soft line 32 which opens into the regulation chamber 30, with a line within the motor installation where cold compressed fresh air circulates. You can then place a tap line 52 between the engine 1 and the inlet cooler R which exits into the flexible line 32 after passing through a regulating device 5 3 which adjusts the back pressure Pc to a value between atmospheric pressure and the back pressure P.

A regulating spring 33 is inserted and acts on the movable throat set 21, the spring 33 regulating the parameter 3 in the linear function kp = aP + B, and provides the pressure difference created by said first throat member 21. The effect of the regulating spring 33 can advantageously is regulated in the event of installation against a movable installation 34.

However, said first throat member 21 could be exposed to aerodynamic vibrations, and it is advantageous to provide the movable throat set 21 with a viscous damping device 6 3 as shown in fig. 4, where like reference numbers refer to the same organs in fig. 2. This viscous damper 6 3 can receive a supply of a viscous liquid 6 4 under variable pressure. The pressure on this fluid source will replace the spring action and the pressure change will replace the action of the moving spring system.

When it comes to the regulating body for the supply of fuel 23, two designs can be used which resp. is illustrated in fig. 2 and 3.

The embodiment shown in fig. 2 operates with a "return" injector 10 for supply to the combustion chamber 8.

The pump 11 feeds under constant pressure to the injector 10 through a supply channel 35, and in addition, fuel that is not injected into the combustion chamber is returned through a return channel 36 which is fed back to the output regulator 23 through a flexible line 37.

This supply regulator for fuel can pass

of a movable member 38 connected through the shaft 69 with the rod 28 belonging to said second throat member 22, the regulating effect being achieved through a variable opening 39, this variable opening or nozzle can take the form of an opening with continuous variation (a needle that sticks more or less into the opening) or can have a discontinuous system (blocking or uncovering of openings).

Preferably, this variable nozzle 39 consists of at least one needle 38 which is designed conically and which protrudes longer or shorter into the opening 70.

The fuel supplied by the flexible line 37 occupies an inlet chamber 40 and is forced to pass through the nozzle opening 39 before the fuel flows into a chamber 41, from where it is finally led through the flexible line 42 to the container 12 through the low-pressure line 43.

By examining fig. 2 it can be seen that when the pressure resting on the rod 28 belonging to the second throttle 42 increases, the rod 28 will be displaced to the left, which results in: firstly, that the recirculation cross-section for the second throttle 22 becomes smaller, which entails a reduction of the primary air supply,

and secondly, a displacement of the movable needle member 38 in the fuel regulator 23 to the left which increases the cross-section of the nozzle flow opening 39 and consequently increases the supply of fuel in the return line 36 with a consequent reduction of the fuel supply which is injected into the combustion chamber.

When the pressure on the rod 28 decreases, the reverse will naturally occur.

In fig. 3, the same reference numbers will denote them

same organs as in fig. 2, but the combustion chamber 8 is supplied with fuel through a "non-return" injector 10a. This injector 10a receives a supply from a pump 1a which in turn sucks from the reservoir 12 via a fuel supply regulator 23 and a supply line 35a.

The supply regulator 23 may consist of a movable member 38a connected to the shaft 69a and the rod 28 belonging to said second throttle member 22, the regulating effect being achieved by means of a variable nozzle opening 39a, the latter may have a continuous cross-sectional variation (a needle that sticks more or less deeply into in the orifice) or a discontinuous variation (blockage or release of the orifice).

Preferably, the variable nozzle 39a consists of at least: a conical needle 68a which protrudes more or less into the opening 70a.

The fuel supplied through the flexible line 37a enters the inlet chamber 40a and is forced to pass the variable nozzle opening 39a before it exits into the chamber 41a from where it passes through the flexible line 42a to the injector 10a through a high pressure line 43a.

In order to maintain a constant pressure difference on both sides of the variable nozzle opening 39a, a rod regulator 44 is used.

This rod regulator 44 consists of a cylinder 45 in which a free piston 46 slides which covers or frees an opening 47 which is taken out in the cylinder wall 45.

The free stamp thus forms:

firstly, a chamber 48 which is located next to the opening 47 and is connected to the inlet opening 40a of the fuel supply regulator 23,

and secondly, a chamber 49 which is located at the opposite end of the opening 47, and is connected to the intermediate chamber 41a belonging to the fuel supply regulator 23.

The floating piston 46 is thus exposed to the pressure difference that exists between the entrance chamber 40a and the intermediate chamber 41a and to the action of a fan 50 which acts in accordance with this pressure difference.

The opening 47 is in connection with an output line 54 which opens into the fuel reservoir 12.

It can be seen from fig. 3 that when the pressure exerted on the rod 28 belonging to the second throttle 22 increases, the rod 28 will be displaced to the left, which results in: firstly, a reduction in the flow cross-section for the second throttle member 22, which results in a reduced supply of primary air,

and secondly, a displacement of the movable needle member 38a and 68a belonging to the fuel regulator 23 to the left and consequently a reduction of the flow cross-section through the variable nozzle 39a, which in turn leads to a reduced supply of fuel to the injector 10a through the supply channel 35a.

When the pressure exerted on the rod 28 decreases, these phenomena will naturally be the reverse.

As for the rod regulator 44, this works so that the floating piston 46 more or less closes the opening 47. The displacement of the floating piston 46 is very small and consequently the force exerted by the spring 50 on the floating piston 46 is practically constant and by this due to the pressure difference between the entrance chamber 40a and the rest chamber 41a essentially constant regardless of the pressure prevailing in the pre-draining chamber 8 and regardless of the supply of injected fuel.

The size of this pressure difference is adjusted by adjusting the spring 50 and for this purpose a movable device 51 can be used against which the spring 50 presses.

It will thus be seen that the supply of fuel through the variable nozzle opening 39a depends exclusively on the through-flow cross-section and thus exclusively depends on the supercharging pressure via the position of the rod 28 belonging to the second throttle 22.'

When one has chosen one or the other of the two designs illustrated in fig. 2 and 4 or fig. 3, one can choose the relevant system for positioning the second throttle 22 and one influences via the spring 29 which acts on the rod 28 belonging to the second throttle 22 the control law that applies between the cross section S^ and the rear pressure P - 4p, or the difference between this back pressure P - AP and the counter pressure Pc which prevails in the regulation chamber 30.

To each size of the cross-section S P corresponds a value for primary air supply Q P and thus a certain amount of supply of fuel Q which is introduced into the combustion chamber, and the size of this fuel supply is determined by the position of the variable nozzle.

Based on the engine's function, the aim is to regulate the supply of fuel Q and prevent, within the limits set by the combustion chamber, the supercharge pressure from falling below a predetermined level,

and enables starting of the turbocharger group before the engine,

enable the combustion chamber to operate

"a night light" that can quickly be increased to full performance without the risk of switching off.

Under these conditions, one must follow a system or a law for the supply of fuel Q which is to be introduced into the combustion chamber as a function of the back pressure P - Ap or the pressure difference between the back pressure P - Ap and the back pressure Pc that prevails in the control chamber 30, as the specified law states as an example of curve 5, where the supercharging pressure P (the relative pressure expressed in atmospheres) has been plotted along the abscissa and the supply of fuel Q supplied to the combustion chambers t has been plotted along the ordinate.

In the absence of back pressure (the pressure in the control chamber 30 = atmospheric pressure), the operating point for the combustion chamber will shift along the curve, if this operating point is stabilized at point K (slow-running engine), it will fall towards point C when the load on the engine increases to approx. 20% of maximum load and up to outside the operating point between C and D (combustion chamber "en veilleuse").

The introduction of a back pressure in the regulation chamber 30 makes it possible to shift this curve towards higher pressure and increase the threshold value for the overcharge pressure.

This simple pneumatic shift of the control range can be used to achieve a switch-on during slow operation, it is also possible to use this shift of the control range to speed up the engine's temperature rise (as the engine runs slowly when the combustion chamber delivers full performance and there are heat exchangers between hot air from the compressor and engine coolant).

Furthermore, the introduction of a back pressure which can rise to the overcharge pressure will make it possible to carry out, by means of the displacement of the regulation area, a height compensation; when the atmospheric pressure decreases, a back pressure equal to the supercharging pressure can be applied, which causes the mentioned other throat organs to open completely and the combustion chamber to deliver full performance (primary air supply and fuel supply have maximum values).

Thanks to the invention, one can thus simultaneously regulate the supply of injected fuel in the combustion chamber 8 and the supply of primary air by influencing the arrangement of the aforementioned second throat organs 22 (the opening 27 and the opening 28a) and the voltage (and possibly the regulation)

on the springs 29 and 50. In this way, it is ensured that the air-fuel mixture in the combustion zone 14 has a mixing ratio that is sufficiently close to stoichiometric to achieve good combustion stability at all engine speeds.

Claims (16)

1. Combustion engine, in particular diesel engine, with an exhaust gas turbocharger and with a diversion channel for the charge air to the exhaust channel in front of the turbine as well as throttling means arranged in the diversion channel with a continuously variable flow cross-section, which throttling means provide a pressure difference between the outlet of the compressor and the inlet of the turbine, characterized in that the throttling means (108, 21, 22) in the main is exclusively controlled by the pressures that prevail in front of and behind the throat, as an increase in the pressure behind the throat leads to a reduction in the passage cross-section of the throat and an increase in the pressure in front of the throat leads to an increase in the passage cross-section of the throat, so that the pressure difference provided by the throat means changes in the same direction as the pressure in the diversion channel (106, 7) in front of the throat. 2. Combustion engine according to claim 1, characterized in that the throttling means (108, 21, 22) include a movable regulating device which is connected to surfaces that are affected by the pressures that prevail in the diversion channel (106, 7) in front or behind the throttling point, the effective total surface which is incurred by the pressure prevailing in front of the throat is smaller than the effective total surface which is incurred by the pressure prevailing behind the throat. 3. Combustion engine according to one of claims 1 or 2, characterized in that the throttle means include a throttle valve body (108a or 25) cooperating with a fixed seat. 4. Internal combustion engine according to claim 3, characterized in that the throttle valve body (108a or 25) is connected to an equalizing piston (108c or 28) which is incurred by the pressure prevailing in the diversion channel (106, 7) before or behind the throttle point. 5. Combustion engine according to one of claims 1 - 4, characterized in that the movable part (valve body 108a or 25) of the throttle means and which is controlled by the prevailing pressure in front and behind the throttle in the diversion channel (106, 7) is also under the influence of elastic means (109 or 108d or 33) which keep the throttle open, especially when before the start of the exhaust gas turbocharger and the internal combustion engine there is equal pressure on both sides of the throttle. 6. Combustion engine according to claim 5, characterized in that the elastic means (109 or 108d or 33) are adjustable. 7. Internal combustion engine according to one of the claims 1 - 6, characterized in that the movable part (108a or 25) of the throttle means and which is controlled by the prevailing pressure in front of and behind the throttle in the diversion channel (106, 7) is under the influence of a liquid damper ( 63). 8. Combustion engine according to one of claims 1 - 7, characterized in that the throttle means (21, 25, 26) are connected to the secondary air flow of a combustion chamber (8) fed with air through the diversion channel (7) whose primary air flow is branched off from the secondary airflow in front of the larynxes. 9. Combustion engine according to claim 8, characterized by a further throttling device (regulating means 24, 27, 28, 28a) for the primary air quantity and controlled by the prevailing pressures in front of or behind the throttling point. 10. Combustion engine according to claim 9, characterized in that the throat organ for the primary air consists of two relative movable parts (22, 28) which form a passage opening with a variable cross-section for primary the air, one part (22) of which is connected to the movable part (25) of the throat means (21) and the other part (28) is affected by the pressure prevailing behind the throat. 11. Combustion engine according to claim 10, characterized in that the part (28) of the throat organ for the primary air which is under the influence of the pressure prevailing behind the throat point is supported elastically, for example by means of a spring (29) against the other part (22) of the primary air regulating means , ie the said second part is connected to the movable part (25) of the throat means (21). 12. Combustion engine according to claim 11, characterized in that the part (22) of the primary air throat organ which is connected to the movable part (25) of the throat means (21) consists of a tube provided with a side opening (27), in which a cup-like pusher open towards the combustion chamber (28) is displaceable, which pusher forms the second part of the primary air throat organ and in its side wall has an opening (28a) cooperating with the aforementioned opening (27). 13. Internal combustion engine according to one of claims 9-12, characterized in that the throttle for the primary air controls a device (23) for regulating the amount of fuel injected into the combustion chamber (8). 14. Combustion engine according to claim 13, characterized in that the adjustable part (38) of the device (2 3) for the injected fuel quantity is connected to the part (28) of the primary air regulating means which is affected by the pressure behind the throttle. 15. Internal combustion engine according to claim 14, characterized in that the adjustable part (38) of the device (23) for the injected fuel quantity consists of a conical needle (68 or 68a) which projects through an opening (70 or 70a), the free cross-section between the needle and the opening edge, in a manner known per se, either directly determines the quantity of fuel injected or the quantity of fuel transported by the fuel pump, but not to be injected. 16. Combustion engine according to one of claims 9 - 15, characterized in that the part (28) of the primary air regulating means which controls the injected fuel quantity can be placed under a variable back pressure which is preferably a pneumatic back pressure on its side facing away from the combustion chamber.