DE3236789A1 - Low-pressure diesel engine with rotary swivel supercharger - Google Patents

Abstract

A low-pressure diesel engine, particularly for powering a passenger motor vehicle, is proposed in which the maximum combustion pressures do not greatly exceed those of spark ignition engines and combustion temperatures over wide ranges are still lower than those in the spark ignition process, so that when used on existing models of this type the engine output can be increased without greater material stresses. The proposal is based on the combination of a diesel engine with a rotary swivel supercharger according to European Patent 0012329, the advantages of this device being retained: greatly reduced fuel requirement, particularly in the partial load range, engine characteristic approximating to the ideal tractive force hyperbola, low speed of rotation, reduced noise, fewer toxic exhaust gases. Use of a Fottinger converter as sole transmission is possible for passenger motor vehicles - even in reverse drive. In order to achieve the object of the invention the compression ratio is reduced in comparison to that of a naturally aspirated engine on the diesel principle to such an extent that ignition of the injected fuel would not take place and the necessary ignition temperature is ensured by heating of the charging air by the corresponding amount. The heating is preferably performed by a flame and its hot combustion gases in the charging air flow. Variants, for example use of electrical energy in any form, are possible. The invention is also applicable to 2-stroke engines. The heating of the charging air... Original abstract incomplete.

Description

Low-pressure diesel engine with a rotary swing loader.

The invention relates to an internal combustion engine that works according to the diesel process works and a rotary swing loader according to the European patent oo 12 329 using the exhaust gas energy, preferably as a free-falling charging unit, Feeds charge air under pressure in the entire engine working area and in which the compression ratio is lowered so far that also taking into account the heat of compression Charge air for the ignition of the injected fuel during the compression stroke of the rotor necessary temperature not reached at least under unfavorable ambient conditions will.

If you disregard known ignition aids, you can safely ignite of the injected fuel, a compression end temperature of around 5000 is required.

According to the gas laws, this requires a high for the normal naturally aspirated engine Compression ratio and correspondingly high pressure.

With car engines, which are still at a pass height and with considerable There are compression ratios of 23 : 1, which results in a final compression pressure of around 70 bar.

It was originally because of the better thermodynamic efficiency The constant pressure method provided by Diesel has been largely modified, sodaQ combustion pressures even above 100 bar are more likely to be regarded as normal.

These ibiotoren are then charged by exhaust gas turbochargers or Comprex can withstand much higher peak pressures, reaching 170 bar or can even be exceeded.

In order for these engines to withstand the high loads, they have to are built much heavier than gasoline engines. The higher weight requires a lot higher price, so that the diesel engine, which is far cheaper in terms of fuel consumption as a car drive only hesitantly prevailed. The rule is that only who drives more than 15,000 km / a, results in relative cost savings.

To remedy this unsatisfactory level of development by the peak pressures, especially in vehicle diesel engines, are comparable to those in inertia of the Otto process are reduced, is the purpose of the invention presented.

High engine weights are particularly uncomfortable in aircraft.

Therefore, there are strong forces in this field to solve the problem set to combine low fuel consumption with low engine weight.

The state of the development in this regard can be determined by the experiments by NASA, so-called 2-stroke low-pressure diesel engines for smaller aircraft to build. This procedure is in the USA journal "Opular Science", April eft 1982, page 103 and flgde. The basis of you is evidently a further developed one Hyperbar process, which in its basics in K. Zinner: Supercharging of internal combustion engines -2. Edition - 1980 - Bpringer-Verlag berlin, can be seen in section 9.7.

The process as developed by Teledine on behalf of NASA is shown schematically in FIG.

At the start of the internal combustion engine 1, this is made up of the compressor 2 and the turbine 3 existing unit driven by the powerful electric motor 4. Lurch the switched Air sucked in at 6 is supplied to valve 5 via the combustion chamber 7 of the turbine 3 and this begins to drive the loading unit 2-5. If the speed is high enough the charge air is heated by compression to approx. 3.7 bar by approx. 1230.

Now the motor 1 can with the heated one after switching the valve 5 Charge air are supplied and its exhaust gases then drive turbine 3 - even when it is switched off Combustion chamber 7.

The compression ratio of the engine has been reduced as far as possible the Ignition temperature for the injected fuel at a charge air temperature of 123 ° is reached. At a boost pressure of 3.7 bar, this means final compression pressures of 55 bar and so a final combustion pressure of 104 bar outside as "low", which is compared to the g @ given by 140 bar for standard diesel engines probably applies.

Incidentally, it is an air-air unit (not shown in FIG. 1) Provide a trained charge air cooler to avoid excessively high charge air temperatures during operation to reduce the amount of charge air. This is certainly necessary because it is a Turbo compressor acts, the pump limit of which is known to be the ratio of delivery rate and delivery head is limited.

In addition, the degree of efficiency is particularly high in the case of smaller units low that the combustion chamber is constantly for energy replenishment, especially in partial load areas must worry.

For car engines, which due to their large number of units not only for the Industries are interesting, but also a special one because of their environmental pollution require attention, this version is already physical in the case of low performance are not usable, but also not to be used because of the effort involved.

In contrast, according to the proposed invention, these mass engines should also be used favorable results are achieved. Not just because of the simple design and clear Apparatus, but also through oprimal behavior in partial load areas - the main field of work the PK @ engines -, due to their favorable characteristics for vehicles and low Consumption values with less polluting exhaust gas.

To solve this problem, the invention provides that at reduced compression ratio of the diesel engine not only through the charge air the pre-compression in the supercharger - which would only mean a shift and does not lead to an optimal pressure reduction in the engine - but by heating it up is heated to the extent that the ignition temperature at the end of the compression stroke of the engine is achieved at a significantly reduced pressure, so that with a suitable injection law the maximum combustion pressure in the order of magnitude that occurs in gasoline engines remain.

This heating of the charge air is preferably carried out without loss a combustion process in lacquer air flow, but it is also another heat source, z. B conversion of electrical energy, applicable.

A normal heating register with heat exchange to the charge air, or without direct mixing of heating gases and charge air is due to the efficiency this transfer is not so cheap and also expensive in terms of material. However One could later, when the engine is running, the: u the #drive of the aotation swing loader still use engine exhaust gases flowing off at a considerable temperature for heating. This would perhaps be in the partial load range and especially with the purge air requirement much more sophisticated 2-stroke engines. tan could also cause hot engine exhaust fumes add to the charge air to warm it up. This mixture could be used directly in the rotary rocker loader, where both gases flow side by side, no effort takes place.

The most practical is one with the one supplied by the rotary swing loader Compressed air-powered combustion of the diesel engine's fuel.

However, with the actually low share of heating energy, which will generally be below 5%, also possible, a more easily igniting medium, such as a liquid gas to use for additional heating.

The charge air heater is probably not ignited by a constantly burning one Pilot flame, but controlled electrically according to the tried and tested state of the art, e.g. through spark gaps or flame arcs. This also makes the Kontrol @ e easy to connect whether the heating is in operation, as well as its throttling until it is switched off in certain engine working areas.

In a vehicle drive, the preferred field of application of Invention, this ignition and control device is expedient with the starting process of the motor coupled.

It is particularly pointed out that this invention If the regulations applicable to the rotary vibratory loader are observed, it is ideally suited for use in 2-stroke diesel engines, as the required purge air is available at the same time. How the advantages of the invention are manifold and easy to use. The gasoline engine is slightly unrequented, so it is cheap to drive vehicles. Unfortunately, because the working mixture of the diesel engine is ignitable only within certain limits of the air ratio, it is basically a diesel engine with regard to the specific fuel consumption inferior, as can be seen in FIG.

In addition, its PV diagram is thermodynamically worse at part load, because cheap parts of the diagram are cut off.

In the case of the diesel engine, it is exactly the opposite. With him are omitted unfavorable parts of the diagram, so that it improves thermodynamically at part load.

Because the air ratio can only be changed within narrow limits, the Exhaust gas temperature in gasoline engines is always high, so that a lot of energy flows off. On the contrary In addition, the air ratio in the diesel engine is particularly high in the partial load range, which, according to Fig. 2, results in favorable fuel consumption and low exhaust gas temperatures leads.

In city traffic, a medium-sized car needs drive power on a level road of approx. 5 kw, which is a mean effective pressure for a 1.5-1 engine at 2,000 rpm pe of approx. 2 bar results.

Compared to this 2 bar, it is important that a gasoline engine must drive strongly throttled in this area - probably below 25% of the charge the full load - and accordingly a negative mean pressure of ci -0.75 bar carries along.

On the other hand, the supercharged swing charger engine according to the Dieitl method experiences an additional thrust especially at partial load when changing gas the difference between the boost pressure and the exhaust gas flowing to the turbocharger of at least +0.5 bar, calculated over the entire work cycle.

Compared to the 2 bar mean effective pressure of the required useful power So -o, 75 and + o, 5 bar are very significant amounts that reduce fuel consumption determine in city traffic.

Lower fuel consumption also means less toxic exhaust gas, in which the Nùx shares also because of the much lower temperatures of the engine work cycle at high air ratio in the proposed low-pressure diesel engine + Rotary swing loader are low.

The invention makes the proposed low pressure diesel engine so as light as the gasoline engine, but retains the advantages of the diesel engine with the ionization swinger: superior specific fuel consumption - especially in the partial load range, which is so important for car drives. High torques Favorable air conditions in the entire working range of the engine even at low engine speeds. The speed of the rotary vibratory loader adapted by the engine is its direct speed Coupling possible when starting the engine, so? without additional equipment immediately heated charge air is available, but also the scavenging air for a 2-stroke Diesel engine.

It should be noted that virtually every model of Otto engines when changing the cylinder cover for this low-pressure diesel process could be used: the pressures remain within the same limits and the temperatures become lower. The wieaerum makes a significant increase in performance without major Effort of the model possible. For convenient accommodation of e.g. a vortex chamber in the Cylinder covers, the valves can be made smaller, as the rotary rocker charger Compensates for flow losses.

There is no mutual dependency on the rotary rocker loader of flow rate and head and no restriction such as the surge limit of turbochargers. It doesn't bother him much if you let the engine open with heated charge air, because the reduction in the charge air mass is compensated for by increasing the charge pressure can be.

If the heating is arranged between the supercharger and the engine, 90 does the heating through Ic e expansion of the charge air. Therefore this arrangement rougher than the one before entering the compressor, because then the Loader has to cope with a larger volume.

The prior art provides a means for heating optimally the respective needs, the working range of the engine and the ambient conditions, adapt. bo, for example, you will be heated up higher at the start and later warmed up atir Engine the Reduce the heating and perhaps lay it out in such a way that you can do without it in the main work areas. rs is a matter of voting of the entire aggregate, whereby it is also important that the heating is by direct Flame and its expensive gases are not very expensive.

It is easy to prove that this direct heating of the La charge air by hot fire gases does not cause any significant disturbance of the air ratio or significant energy losses. At an air ratio of 2, 28.6 kg of air are required for 1 kg of fuel in the engine. In order to heat this amount of air by 1000 in addition to the compression heat, 720 kcal are required, i.e. about 72 g of diesel oil, which in turn requires 1 kg of air for combustion, i.e. 3.5; the amount of work, so that the air ratio changes to 1.93 - which would be negligible! The additional heating must also be taken into account in the absorption curve diagram of the motor; But since you will hardly go below an engine compression ratio of 7: 1 in order to maintain a favorable thermodynamic efficiency, a charge air compression of 2.5 bar can be expected without exceeding the maximum combustion pressures in a gasoline engine, provided that a corresponding injection law is used used for the charged diesel engine. Under favorable ambient conditions, however, this boost pressure already results in a sufficiently high charge air temperature so that there is no need for additional heating in full load operation. This means that the motor slack lines do not change in the decisive area compared to the usual values. The reduction in throughput by the However, heating is of no concern in the Pnfahrberêich and during partial load operation, since there is a considerable air ratio in any case.

An execution scheme of the proposed invention is based on the Fig. 3 given as a summary of the previous description.

The rotary oscillating loader 8 in FIG. 3 supplies the in its compression ratio appropriately adapted internal combustion engine according to the diesel process 9 with charge air. This is generated by the flame 10 through direct heat transfer and through mixing heated with their fire gases. nine ignition and control position 11 after the prior art controls this process, the heating intensity depending on the @ needs of safe ignition and not unnecessarily high temperature according to control e is regulated via heat sensor 12, for example. The flame 10 is produced by the fuel pump 15 saved.

14 is the temporary possible driving connection between the engine and rotary oscillating loader during the start-up process.

This is the state of the art in rotating oscillating link technology.

Instead of the flame 10, an electric heating system can also be used, for example or an arc of flame can be arranged.

It is also possible to heat the charge air at point 10 A heating register, not shown, which must be heated externally at the start :, while later, after the start of the engine, the register is heated by engine exhaust gases take place 9011-th.

Also a direct admixture of hot engine exhaust gases - after a different one initiated start of the engine - to the charge air is without graphic representation Understandable according to the state of the art. e The advantages of the low-pressure diesel engine according to the invention, including the incomparably favorable characteristics, come into effect particularly impressively when they are used in connection with the Use of such a facility zuir.

Drive of a highly motorized vehicle, e.g. a car, is considered. The transmission required between the vehicle and the engine can then be used as a Föttinger converter form. This @ m could also be followed by a distinctive mountain passage. It but could also be self-reinforcing according to the prior art, such as with a Rieseler gearbox and even reverse gear by reversing the function Integrate impeller and idler.

The gear pumps available for circulating the operating medium can thereby at the same time serve for locking-free braking.

The ratios are optimal when this transmission is a Trilok converter whose coupling point corresponds as closely as possible to the maximum engine torque.

Claims (11)

Low pressure diesel engine with rotary swing charger claims. 1. Combustion engine based on the diesel process, using a rotary oscillating loader using the exhaust gas energy, preferably as a free-moving charging unit. Loading # uft under pressure throughout the engine working area, with the compression ratio of the Elotoru is lowered so far that also taking into account the heat of compression the charge air at the Kompressionshuo des? ctors that for that of the injected fuel necessary temperature per se is not reached, characterized in that the Charge air is additionally heated before entering the working cylinder of the engine. 2. Device according to claim 1, characterized in that the heating the charge air takes place by arranging a heat source in the charge air flow. 3. Device according to claims 1 and 2, dad. gek. that a low-loss Heating through direct mixing of the charge air with fire gas. a combustion process he follows. 4. device according to claims 1 and 2, dad. gek. that a low-loss Heating through the arrangement of a heat source fed by electricity, flame arc or glow device, takes place in the charge air flow. 5. Einruchtung according to claims 1 to 4, dad. there?:. one after de state of the art trained control organ is provided, which ignition and the effectiveness of the heating device is monitored and regulated. 6. Establishment according to claims 1 to 3, dad. gek. that for heating a more flammable medium, e.g. propane gas, is used. 7. Device according to claims 1 to 5, dad. gek. that for heating the same medium is used that is used to operate the engine. 8. Device according to claims 1 to 7, dad gek. That the triggering the heating is coupled with the starting process, with an advance as well as a Protection against failure of the heating is provided. 9. Equipment according to Claims 1 to 8, as a low-pressure 2-stroke diesel engine, dad. gek. that at the start and in the work areas in which the energy of the engine gases even with additional heating for the rotary swing loader, a driving force is not sufficient There is a connection between the rotary vibratory loader and the engine, which is automatic is switched off as soon as the @core can be cleared. 10. Device according to one of claims 1 ois 9, which is used as a drive is used in a highly motorized vehicle, preferably in a car, dad. gek. that you use a hydrodynamic gearbox between the rotor and the vehicle Converter with or without mountain gear is connected downstream, the converter of the Trilok type corresponds and is designed so that its coupling point approximately the highest engine torque is equivalent to. 11. Device according to claim 10, dad. gek. that the converter alone represents the complete vehicle transmission, in which the reverse gear is also reversed the function of impellers and idlers is integrated, while that for the media circulation Existing gear pumps can also be used as wear-free brakes can.