Untitled record

A supercharged internal combustion engine having a dual-drive supercharging system. Supercharged internal combustion engines whose supercharging fan is driven via a differential gear to obtain an engine speed independent supercharging pressure detection are known. They require a special design in order to give a desired boost pressure and torque curve, which increases steeply to lower speeds, without additional control elements.

This system can be added to an exhaust gas turbocharger, which is effective in contrast to its otherwise conventional operation even at low speed. This creates a charging system with two drives. Simplifying the same, German Patent 1170193 describes an internal combustion engine having such a system in which one drive is exhaust-driven while the other is the second output branch of a transfer case driven by the engine shaft and both act on a single blower.

This simple solution has the further disadvantage that the exhaust-driven supercharger adds only to the mechanical supercharger without detaching it, so that in such operating conditions in which the exhaust-driven supercharger could muster the required charge alone, yet additional and useless mechanical charging power must be expended ,

It is an object of the present invention to provide a method by means of which the exhaust-driven supercharger drive automatically and without any regulating devices supports the mechanical supercharger drive in a constantly variable manner, depending on the operating state, until completely detached and, moreover, also fully automatic, delivers power to the output shaft of the machine.

This object is achieved according to the invention in that the coming from the transfer case mechanical supercharger drive and the exhaust-driven drive combined with an acting on the fan shaft drive in a conventional manner via a second, smaller, acting as an addition or (and) transfer case differential gear are.

The mechanical supercharger drive can be in this case in certain operating conditions to a power to the Nutzleistungswelle dissipative output.

The increase in cost by a .solches second differential gear can be kept within limits that simple friction wheels are used to form the second, smaller differential gear, which is possible with the low drive torque of a very fast-running radial fan.

Further features of the invention are that in a conventional manner a reverse rotation lock is provided in the exhaust-driven drive, further, that the second differential gear in a conventional manner in varied form of a hydrodynamic transmission of Föttingerbauart with at least three wheels, and finally, that this Föttingergetriebe is equipped in a conventional manner with an organ for filling and emptying and thus in addition to its differential gear function that of a machine and the power output positively binding or separating clutch takes over.

It is known to combine by means of complicated gear and control organs a direct mechanical supercharger drive with an exhaust turbine engine so that they influence and complement each other, the turbine can also deliver excess power to the output shaft. In such arrangements, no differential drive is provided for the loader, but a complicated differential control member for controlling the speed of the directly driven supercharger has been constructed. Such solutions are due to lack of automatism and lack of simplicity of the proposed here considerably.

It has also been proposed by the same inventor to provide an exhaust gas turbine alone (without supercharger) with mechanical drive of the supercharger via transfer case and to let act mechanically directly on the Nutzleistungswelle. This arrangement is more suitable for relatively large machines. It offers the advantage of very high starting torques, but does not allow the mechanical supercharger drive to be supported by the exhaust-gas turbine drive or even automatically detached.

A known arrangement in which the exhaust turbine and supercharger are combined via a differential gear directly to the machine shaft, similar to the invention by the coupling of the loader drives in the differential gear, but it differs from her fundamentally in the rest of the scheme as well as in purpose and in effect. The rest of the scheme is different in that there are not two differential gear available, but just - in the coupling specified here - for ras work within the meaning of the invention are essential. The purpose is different, since the very purpose of the present invention, the gradual, automatic replacement of the mechanical drive, is neither sought nor maintained. The effect is finally different, because a reverse rotation of the turbine and power losses are accepted and because by the power dividing main distributor gear in the present invention, a completely different torque detection is obtained.

Also, the attachment of a freewheel such that in such an arrangement the differential gear becomes such only when the turbine starts to work proves only the inventive effort made on this field, but does not change the fundamental difference with the System of the present invention. Even such an arrangement neither allows the mechanical supercharger drive continuously detach until turbine power is delivered to the power output shaft, nor does it in combination with such an effect, the characteristic, automatically increasing steeply lower rotational speed torque detection of the present invention.

Hydrodynamic differential gears of the type proposed here as Varlantenausführung for the small differential gear are known per se, as noted, but not in the particular arrangement which is described here, especially not for driving a high-speed loader by means of two different drives. The simultaneous use of such a transmission as a non-positive separating clutch between machine = and power output shaft by means of a known per se for filling and emptying is also new. The progress made over the acquaintance by the new arrangement results from the above statements of itself.

The invention is explained in the figures.

F i g. Figure 1 illustrates an example embodiment in which a differential drive gear serves as an add-on gear. It is connected between the very fast rotating exhaust gas turbine shaft and the likewise high speed centrifugal load shaft; F i g. Fig. 2 shows a differential gear transmission as an addition gear. It is arranged so that one of its three shafts directly drives the medium-speed rotating shaft of a supercharging blower, while another is driven by a reduction gear from the exhaust turbine and the third is connected directly to the free output of the transfer case; F i g. FIG. 3 shows a small hydraulic torque converter as an addition gearbox. It is directly switched between high-speed exhaust turbine shaft, medium-speed supercharger shaft and free output of the transfer case.

In F i g. 1, M is the engine with the intake air line 9 and the exhaust line B. He drives in a known manner the transfer case 2, on the one hand, the power output shaft 11 emerges. On the other hand, the free output 3 comes out of the transfer case via gears 3 a and 3 b. This free output would drive directly in the normal design of such engines, the supercharger. In the arrangement according to the invention, it drives the satellites 4 of the addition gear 7. This organ consists in F g. 1 from a Reibraddiffferentialgetriebe. The sun gear 10 b of this transmission drives the centrifugal fan G, and the sun gear 10 a is driven by the exhaust gas turbine 5. This or the sun gear 10a according to the invention contain a not shown backstop, z. As in conventional freewheel design, so that they can not rotate in the opposite direction.

The arrangement operates as follows: The output 3 tries to drive both the turbine 5 and the blower 6 in the same sense. The backstop in the turbine drive but prevents rotation of the turbine in this sense (which is antipathetic for them), so that only the fan is driven. It is driven at twice the speed, as the satellites also rotate.

As soon as the exhaust gases act on the turbine, they drive the turbine in the right direction, ie in the opposite direction to the blower. Due to the interaction of the satellites, this reverse rotation of the turbine rotor causes an effort to drive the fan even faster and, on the other hand, depress the speed of the output 3. When the amount of exhaust gas has become sufficiently large, the turbine drives the fan all by itself, and the output 3 stands still. The turbine thus automatically releases the mechanical loader drive 3.

If exhaust gases are available beyond the necessary, predictable amount, then the exhaust gas turbine starts to drive the output 3 in the opposite direction. This means that the turbine now returns energy to the transfer case and drives the output shaft 11 in addition to the motor. At this moment, the addition gear 7 becomes a transfer case, and the main gear 2 becomes an addition gear.

In the manner described, the turbine outputs its excess power in the automatic transition to the power consumption point.

F i g. 2 shows another embodiment. The exhaust gas turbine 5 is here connected together with a Verdrängerverdichter 6. The addition gear consists of a bevel gear differential gear 7, which is located at the location of the spur gear 3 b in Fig. 1. Since Verdrängerverdichter rotate much slower than centrifugal compressor, a gear differential can be used here. But now to achieve the high speed of the turbine, a reduction gear 12 (reduction ratio about 1: $) between the turbine 5 and sun gear 10a is arranged. The arrangement of the F i g. 2 works the same way as the F i g. 1.

F i g. Fig. 3 shows another example embodiment which can be easily realized since it is very simple and without difficult mechanical problems.

Here the mechanical coupling of the high-speed turbine shaft is replaced by a hydraulic coupling, so that all difficulties are eliminated from this side.

The function of the addition gear is taken here by a hydraulic differential gear 7, which is built in the manner of a hydraulic Föttinger torque converter, but has three free waves. The gear 3 a, which forms the free output of the transfer case, drives the outer peripheral bell 4 of the torque converter 7. The exhaust gas turbine 5 drives the small central rotor 10 a. The larger central rotor 10 b drives the positive displacement blower 6.

This embodiment operates similar to the mechanical addition gear of the F i g. 1 and 2. It also allows for further simplification. In previous patent applications, it has been proposed to replace the conventional classic engine master clutch with a small hydraulic clutch in the differential drive supercharger drive train, e.g. B. by .eine hydraulic clutch at the location of the hydraulic D.rehmomentwandlers just described 7. The inputs and. Disconnection of the engine takes place in a conventional manner by filling or emptying of such a small hydraulic clutch. It is now proposed according to the invention to equip the Föttinger converter 7 with this coupling function in addition and thus replace him with the classic main clutch. In order to achieve this, it is only necessary to provide for the possibility that the Föttinger converter 7 will be filled when the clutch is engaged and emptied when the clutch is disengaged. The details of this manual or automatic operation are known to any person skilled in the art.