DE3343677A1 - Reduction of the heat and pollutant emissions in diesel engines - Google Patents

Abstract

It is shown that in diesel engines, reduction of the NOx emissions and reduction of the CO - , CH - and CO2 emissions is possible without power and consumption losses, if both the combustion process and the engine cooling, the exhaust turbine and the arrangement of the catalytic converter and the soot filter are designed with this objective in mind. The measures for the CO2/air balance are achieved by suitable elements for combustion of vegetable oil instead of fossil fuels.

Description

T i t e 1: Reduction of heat and pollutant

emissions from diesel engines The reduction of NOx emissions at Diesel engines in combination with the reduction of noise and waste heat emissions as well as the hydrocarbon compounds including CO2 requires that the previous conflict of goals that existed between the NO and the CO and CH reduction, is also resolved, as is the conflict of objectives between harmless exhaust gases and optimal ones Consumption values at all.

Since both the NO bond costs heat and the unburned CH and CO components mean heat losses, there is no physical conflict between Removal of pollutants and optimization of the engine heat balance.

The opposing processes of CH- and CO on the one hand and NO, on the other hand, because in all previous work processes in the engine always all cylinder air is mixed with the fuel. Even with the antechamber or vortex chamber there is an excess of oxygen in the chamber in the lower partial load range, and in the The air in the cylinder becomes even more violent in the further course of the process mixed with the fuel gas from the chamber.

In the German patent P 2 241 355 it is recognized that it is possible to remove the excess air from the combustion zone air by means of a high air swirl to separate that in the rotating heap of mass the heavier, because not burning, air is separated and centrifuged on the combustion chamber wall. This excess air remains but exposed to increasing heating in the given shape of the combustion chamber. So arise still more NO bonds than will be accepted by future emissions legislation will.

With these procedures, the CO and CH values are also used for future requirements still too high, because with the shape of the combustion chamber shown, the one in the central combustion zone any unburned CO and CH residues first emerge from the combustion chamber and in the course of the expansion stroke no longer with the one coming out of the combustion chamber too late Excess air to be mixed.

In order to meet the future emission requirements, the mitt2 241 355 given possibilities can be extended to the effect that the between the burning zone and combustion chamber wall rotating excess air before the stoichiometrically burned Combustion zone air flows out of the combustion chamber, also in the Cylinder space rests against the cylinder wall and thus prevents unnecessary work in the hot combustion chamber NO gases arise and there are unnecessary CO or CH gases on the cold cylinder wall stay. So where, according to the teaching given so far, there are sharp edges to close off the combustion chamber were necessary, an outlet was provided for the new function, which the excess air no longer lets flow out last, but first.

Especially when it comes to plant-based instead of fossil fuels Use oils to also reduce the increase in CO2 in the free atmosphere, it is important to store oxygen-rich air on the cylinder wall in order to prevent the slideway to protect from the combustion residues of the vegetable oil. Vegetable oil has against Petroleum has the advantage that it must first grow before it can be burned in the engine. In order to be able to grow, the plant must emit at least as large a proportion of CO2 from the air, as released into the air when the vegetable oil is burned will. But before 100% vegetable oil instead of crude oil in the engine ran without problems can be, the combustion process must be changed so that the fuel does not accumulate on the nozzle, combustion chamber walls or piston sealing jacket and cylinder liner. Vegetable oil must be sufficiently preheated and until it is completely burned in the hot Burning zone are kept. In order to achieve this, a number of measures must be taken go beyond P 2 241 355. No rotation is allowed the air mass disturbing edges, such as valve pockets or those shown in P 2 241 355 sharp inflow edges at the combustion chamber opening or for the fuel jet provided incision (nozzle nozzle). The outflow from the The combustion chamber is so facilitated by a turned bevel with a large radius that only the greater kinetic energy that comes from the rotation of the fresh air results, is enough to get this I, 'ift: ant ii first from the flrennrain' flow as soon as the piston begins its downward movement. The start of burning falls and the piston reversal movement together, so the excess air is quickly withdrawn the heating, so that the formation of NO is prevented. The direction of flow of the Excess air is controlled by the new slope so that the edge of the bowl and The piston crown is less heated. This in turn allows the shown static heavy-duty ferrum pistons with one already arranged above the piston rings tightly fitted running surface that does not adhere to combustion residues in the piston sealing jacket housed piston rings can come.

Furthermore, the previous water cooling can be replaced by an oil cooling and instead of 5 cylinders there are now only 3 cylinders for the same Performance required.

All of these follow-up results from the lower heating of the Material and the lower heat losses of the working gas are also shortened the evaporation and burning times of the fuel, so that previously for single-jet combustion required start of burning before TDC can be shortened considerably. That is, the Excess air can therefore escape in good time before oxygen is released from it for NO binding is taken. There is also an excess of oxygen in good time available in the cylinder to post-burn CO and CH.

For high-revving smaller diesel engines with this called Duotherm Combustion process, the intake valve is opened briefly during the exhaust stroke, so that additional fresh air is blown into the exhaust gas, including the reduction to 3 cylinders in a group is particularly important because with four-stroke engines and 3 Cylinders, the firing order and valve opening times have approximately the same crank angle.

The group of three also gives the greatest charging effect, so the Previous performance disadvantages for diesel engines are eliminated and emission regulations are not hampered by performance degradation.

The noise emissions of the diesel engine are already reduced by the low rate of pressure increase reduced in the case of single-jet combustion. Due to the more precise mixing and thus faster and later combustion, they are further reduced, as well as by the narrower running clearances of the iron piston to the previous aluminum piston.

The arrangement of an additional CO-CH catalyst at the turbine inlet and a soot and particle filter at the turbine outlet brings with the increased exhaust gas temperatures the cylinder volume reduced by a ratio of 5 to 3, due to the lower material heating became possible, good efficiencies for pollution and noise abatement.

The reduction of heat emissions, i.e. fuel consumption, is 3 to 2 from the previously common chamber diesel to the new Duotherm engine. the The previous radiator front for water cooling is no longer required, the remaining oil radiator is tailored to the requirements for cabin heating. With certain vegetable oils the circuit for cooling, lubrication and fuel can be interconnected will. With mineral oil lubrication, only the lubricant and coolant are the same.

The opposite wheel of the oil pump carries the two with 3 cylinders Counterweights for balancing mass moments. Sufficient for the cooling air of the oil cooler also with truck diesels of this type electric fan.

By installing the entire injection technology in the cylinder head the cylinder head heat is also used to preheat the fuel.

The set goal with the help of an improved diesel engine Combustion process, the performance disadvantages compared to the gasoline engine, which in terms of pollutant and heat emissions is far inferior to the diesel engine, to eliminate is on can be reached along the suggested route.

Description of the picture Fig. I The piston (1) with its combustion chamber (2) has at its opening (3) a bevel (4) with a radius (5) into the combustion chamber (2) passes. In the middle of the combustion chamber (6), the hot combustion zone (7) rotates around the the excess air (8) rotates around, the higher the speed, the lower the lower Temperature and thus greater mass energy than the gases in the combustion zone (7).

As soon as the piston (1) has passed the cylinder chamber (9) after its reversal point enlarged in the cylinder (10), the excess air (8) flows over the radius first (5) and the incline (4) in the cylinder space (9) and is stored on the cylinder (10) on. As the piston (1) descends further, the combustion zone air (7) is released from the outflowing excess air (8) drawn. This creates in the cylinder space (9) the same arrangement as it was before in the combustion chamber (2).

An iron alloy is provided as the material for the piston (1), which only expands to the extent of the cylinder (10) when the heating is low. So the slide (11) on the sealing jacket (12) above the first piston ring (13) can be arranged where they provide an effective preliminary seal due to their tight running clearance results.

The injection nozzle (14) is arranged above the slope (4), whereby a cutout (snout) in the combustion chamber opening (3) is avoided. The fuel jet (15) extends through the edge of the combustion chamber in the direction of the combustion chamber wall hindered and affected the rotating air at around 60% of the largest combustion chamber diameter.

The theoretical point of impact (16) is in the lower quarter of the Combustion chamber (2). Due to the air swirl, the jet (15) is first in the circular path diverted.

Fig. II shows a cross section of the motor housing (17).

On the housing (17) sits the cylinder head (18), in which the inlet swirl channel (19) and the outlet channel (20) is cast. In the lower part is the cylinder (10) only cooled by the inner oil splashes (21) and (22). In the upper part, from the Sealing jacket (12) is covered, an external cooling (23) is provided, for which also Oil can be provided as a coolant.

The oil coolant is fed into the oil cooler (25) by the oil pump (24) and promoted from there into the oil sump (26). An electric fan is used to convey the cooling air (27) used. Sit on the wheel (28) of the oil pump (24) rotating in the opposite direction to the crankshaft the balance weights (29) for the moments of inertia released in 3-cylinder engines cylinders 1 and 3.

The camshaft (30) has a pre-cam for the inlet valve (31), which opens the inlet valve (31) briefly in the exhaust stroke to provide fresh air for the CO and CH reduction in the cylinder (10) to blow. Additionally but CO and CH can also be reduced by the fact that in the case of the Working method greatly increased exhaust gas temperature a catalytic converter (32) between the engine and exhaust gas turbo (33) is arranged. The inevitable bursts of smoke of the charged Diesel engines are intercepted by the soot filter (34), into which the exhaust gases flow radially and passed axially into the exhaust line (35).

Claims (14)

Claims The reduction of heat and pollutant emissions in diesel engines by separating the combustion air from the tfbersc.hußluft about the previous result achieved with chamber and chamberless diesel engines addition, characterized in that the separation of the working air in stoichiometric mixed combustion zone air (7) and excess air (8) also outside the combustion chamber is retained in the cylinder chamber (9), and this is achieved by shaping the combustion chamber (4) and (5) is achieved, which has the effect that the excess air exiting first (8) the combustion zone air (7) draws in and the combustion chamber material before heating and the Working air protects against cooling, and thus without thermodynamic losses Renewable fuels are used to compensate for the CO2 air balance can. 2. The reduction of heat and pollutant emissions according to claim 1, characterized in that the fuel jet through the edge of the combustion chamber at its Expansion in the direction of the combustion chamber wall is prevented, the rotating air mass at about 60% of the largest combustion chamber diameter and the theoretical point of impact lies in the lower quarter of the combustion chamber. 3. The reduction of heat and pollutant emissions according to claim 1, characterized in that the ratio of the area of the combustion chamber opening to The combustion chamber diameter is the ratio of the combustion zone air to the total working air at full load. 4. The reduction of heat and pollutant emissions according to claim 1, characterized in that the helix angle (4) is determined so that the exiting excess air does not detach itself from the piston crown and for about the same Flow rate is measured. 5. The reduction of heat and pollutant emissions according to claim 1 and following, characterized in that the combustion time and the with the combustion rate controlled by the injection quantity to that required according to claim 1 Sequence of gas exit from the combustion chamber are coordinated. 6. The reduction of heat and pollutant emissions according to claim 1, characterized in that in the exhaust stroke by a brief pre-opening of the Inlet valve fresh air is mixed with the exhaust gas flowing out to reduce the CO and Burn remains of CH fuel. 7 The reduction of heat and pollutant emissions according to claim 1, characterized in that the reduction in CO and CH fuel residues in takes place a catalytic converter, which is arranged between the engine and the exhaust gas turbine. 8. The reduction of heat and pollutant emissions according to claim 1, characterized in that the exhaust gases at the exit of the turbine radially into a Soot and particle filters are passed and only in or after the filter into the axial flow are deflected towards the outlet pipe. 9. The reduction of heat and pollutant emissions according to claim 1, characterized in that the rate of evaporation of vegetable Fuels is boosted by placing them in the hottest part of the combustion zone be injected. 10. The reduction of heat and pollutant emissions according to claim 1, characterized in that the vegetable fuel in one in the cylinder head integrated injection pump and preheated in a nozzle. 11. The reduction of heat and pollutant emissions according to claim 1 and following, characterized in that the sealing jacket of the piston by the constructive dimensioning of the piston crown so little heat is supplied that it already can be made gas-tight above the first ring that the rings through Vegetable oil residues cannot stick together and great gas tightness for starting the engine with vegetable oil is given. 12. The reduction of heat and pollutant emissions according to claim 1 and following, characterized in that the required we temperatures in Catalytic converters can be made by having only 3 cylinders instead of 4 or 5 Cylinders are used, which are combined into an exhaust group, and so on the effectiveness of the CO-CH catalytic converter, the exhaust gas turbine and the exhaust gas filter as well as the air swirl in the cylinder increases. 13. The reduction of heat and pollutant emissions according to claim 1, characterized in that in the further reduction of NO in the combustion zone (7) a catalytic converter is also provided. 14. The reduction of heat and pollutant emissions according to claim 1 and following, characterized in that the as late as possible Burning process required faster evaporation of the fuel achieved is that the fuel serves as a lubricant and coolant and thus always on constant temperature is kept as high as required for vegetable oil is.