DE943202C - Working method for four-stroke internal combustion engine working with mixture compression and spark ignition - Google Patents

Description

Working method for with mixture compression and spark ignition working four-stroke internal combustion engine To the specific fuel consumption. from the internal combustion engines working with mixture compression and instant ignition To reduce, an increase in the compression ratio is generally sought. However, high-knock-resistant fuels must be used.

The present invention aims to reduce the specific Fuel consumption by increasing the thermodynamic efficiency, without that higher octane fuels would be required. Thereby individual measures applied that in mixture-compressing internal combustion engines, considered by themselves, are known per se, in their simultaneous application and coordination with one another but one. result in novel success ..

It is a combination of the following features: a) The aspirated The amount of charge is determined by closing the inlet valve before the end of the intake stroke of the piston so that the sucked-in fuel-air mixture in the working cylinder is subjected to stretching and thereby cooled; b) by appropriate dimensioning or formation of the compression space is the previously stretched charge during the compression stroke so highly compressed that its condition, conditioned by pressure and temperature. at full open throttle just below that by fuel property, - Combustion chamber shape and engine speed given. Knock limit lies; c) the outlet of the Combustion gases or the opening of the exhaust valve begins on or before they are reached of the outer dead center during the working stroke.

The feature a) has become known as a measure to avoid being charged. Machines to limit the boost pressure or to regulate the filling at part load. It is also known from steam engine construction that in constant pressure machines a, "Smaller filling related to the cylinder size due to further expansion Better utilization of the direct current process results than with a larger one Filling in the same cylinder is the case.

The features b) and c) are known in principle from textbooks. In the German patent specification 320921 is z. B. the application of features a) to c) described with the aim of further reaching the one known from steam engine construction Expansion. to transfer to constant pressure combustion engine with compression ignition and a possibility of regulating the amount of charge. create. Besides that this Patent specification on what was then still insufficient knowledge of the essence. . of the combustion process based and requires a pure constant pressure combustion, it also relates exclusively on a diesel process.

In contrast, the present invention provides a reduction the specific fuel consumption in mixture-compressing internal combustion engines aimed at, by increasing the »thermodynamic« efficiency, without that fuels with higher octane numbers would be required .. The kinetic Energy of the incoming charge for processing the fuel particles to a large extent can be used.

The invention provides for this by simultaneous application of these and other features, the stretch ratio versus the compression ratio increase and thereby achieve a higher thermodynamic efficiency.

The invention is based in detail on the fact that by earlier closing, of the inlet valve does not only limit the amount of charge drawn in, but rather. also by changing the inflow law, a back slide of the sucked in Avoided charge and the kinetic energy of the inflowing. Charge exploited will. In connection with this, a higher constructive compression ratio is possible, This is achieved by higher pistons or milling off the cylinder cover. Corresponding the smaller amount of charge and the larger .Dehungsrat can the outlet be opened later than usual, which means that the expansion and extension losses can be lowered.

The extent of the earlier closure of the inlet valve also determines the Size of the compression space, since at the end of compression the pressure and temperature of the Charge just at the limit given by the I <Uop strength of the fuel - a, be put. Both features can be chosen so that the reduction the amount of charge is just balanced in terms of performance, is achieved by increasing the thermodynamic. Efficiency and the utilization of the kinetic. Energy of incoming charge.

By using the kinetic energy of the incoming charge shortly before the earlier closure of the inlet valve in connection with an increased Compression ratio, which in turn is made possible by the earlier inlet closure is, as well as the fact that according to the smaller amount of charge and the larger Expansion ratio the outlet can be opened later than usual, thereby reducing the Expansion and outflow losses can be reduced, the overall effect is which is new and much cheaper than the previously known one, through expenditure the expected effect of the individual characteristics alone.

The invention enables better utilization of the working cylinder introduced amount of charge, bearing from the previously common view that a, more favorable Efficiency can only be achieved if the largest possible air weight in the Cylinder is introduced. is deliberately departed.

By the amount of advancement of the inlet closing time it becomes when using the invention proposals possible to achieve a torque curve, which with falling speed a sharp increase in torque with simultaneous Reduction of the specific fuel consumption. results.

About the favorable operating characteristics of the engine achieved in this way in terms of power and fuel consumption according to quantity and type, even with throttling the amount of charge by opening the throttle valve less, i.e. with - reduced Obtaining performance becomes the further. Invention proposed according to the mixture if the throttle valve is less open, well before the inner dead center is reached to ignite during the compression stroke (increased pre-ignition), so that also during partial load operation the maximum compression earth pressure is achieved through pre-combustion of a part of the mixture will. The ignition adjustment can be a function of the throttle valve opening take place.

The structure resulting from the method according to the invention has also the advantage that two different motors with the same components Uses can be produced, namely a series with higher Power and normal specific fuel consumption and one with lower Performance and extremely lower specific fuel consumption, with both Engines only the piston and the camshaft are different, but interchangeable with each other are.

Pistons. and camshaft of the second set can be the one according to the invention Process be designed accordingly, d. H. the cams of the camshaft are after the invention. procedure required valve opening or Adjusted closing times, while the pistons are made higher.

The method is also particularly suitable for the conversion or the Reconstruction of oversized doors, whose full maximum performance is not or only temporarily is needed on lesser. Fuel consumption, with almost the same Torque in the lower speed range and reduced maximum output. The invention accordingly, the compression ratio is suggested in these cases of subsequent conversion increase through higher pistons.

According to the proposal, the new valve timing is achieved by partially grinding off the old cam surface (approx. 0.5 mm), welding it on; Naturally hard material and re-grinding. the new. Cam shape achieved.

Due to the greater surface hardness of the applied. Tread material the valve acceleration can be increased and thus despite the shortened control time of the cams, respectively. Valve lift can be maintained. As a rule, by adjusting the Camshaft the timing of the exhaust port to be placed later.

The drawing shows the new process or the one resulting from it new construction explained in more detail, and. although Fig. i shows a schematic working diagram for normal gas exchange and the gas exchange modified according to the invention for full load, Fig. 2 the same for part load, Fig. 3 a, 3 b one. Cut through one modified according to the invention. Engine, Fig. Q. a modified according to the invention Camshaft in section.

The solid lines in Fig. I correspond to the normal Gas exchange at full load, while the dashed lines indicate the gas exchange ignited also indicate at full load. As you can see from this, is after the changed Moving the compression space from Vco with normal gas exchange to Vcl with the invention Gas exchange is reduced, either through a higher piston design or a corresponding one Change of the stroke ratio or the cylinder head. The valve closure of the intake stroke takes place in the method according to the invention already in point ES, so that how one can see from the dashed line in the diagram, pressure (and temperature) of the amount of charge, which is at I in the normal procedure, reduced to point II. Still will as a result of the reduction in the compression space marked by III, at Normal method also achieved compression pressure in the method according to the invention reached again, so that the pressure increase in combustion of the mixture in both Cases is the same.

The opening of the outlet valve, which in the normal process is already in Point Aö takes place, takes place in the method according to the invention only at point Aj; IV. At part load there is even a significant improvement compared to the normal procedure or pressure increase by the method according to the invention, achieved by the ignition in point V.Z., d. H. so before reaching the inner dead center of the compression stroke (after changing the ratios according to the invention). As the diagram shows Both the pre-compression pressure can be used in the case of partial load operation according to the method according to the invention as well as the final pressure achievable after combustion compared to the normal process can be increased.

Fig. 3 a shows a section through one according to the present Procedure. working cylinder i, whose. Normal piston 2 is increased by the height 3.

Fig. 3 b shows a. Section through one according to the present method. working cylinder i, in which the combustion chamber delimitation opposite the piston is lowered by the height 3.

With the associated camshaft q. the cam 5 is through. Welding a hard metal layer 6 (Fig. q.) Changed so that the closing or opening time of the associated. Valve 7 and, the corresponding setting time according to the procedure is modified.

Claims (5)

PATENT CLAIMS: i. Working method for with mixture compression and Instant spark ignition, four-stroke internal combustion engine, chine, characterized by the simultaneous use of the following in constant pressure injection internal combustion engines known measures: a) The amount of charge sucked in is known per se by closing the inlet valve before the end of the suction stroke of the piston so, limits that the sucked-in fuel-air mixture in the working cylinder of an expansion is subjected and thereby cooled; b) the previously stretched charge is in. an is known to compress so high during the compression stroke that you through. pressure and temperature related condition with throttle fully open just below the knock limit given by the fuel properties, the shape of the combustion chamber and the engine speed lies, so that ß the constructive compression ratio is higher than in four-stroke internal combustion engines without charge limitation; c) the outlet of the combustion gases or the opening of the outlet valve begins in a manner known per se before reaching the outer dead center during of the working stroke, but later than with four-stroke internal combustion engines without load limitation, possibly only in the outer dead center. 2. Procedure, according to. Claim i, thereby it indicates that the inlet closes on the intake stroke, at least 2o ° before it is reached the outer dead center takes place. 3. The method according to claim i and 2 for partial load operation when throttling the amount of charge by opening the throttle valve less, thereby marked, that the ignition during the compression stroke well before the inner dead center is reached takes place, so that by pre-combustion of a part of the mixture also during partial load operation the maximum final compression pressure is reached. 4. The method according to claim i to 3, characterized in that the ignition adjustment as a function of the throttle valve opening inevitably takes place. 5. Application of the method according to claim i to 4 on those four-stroke internal combustion engines that are converted to lower fuel consumption with almost constant torque in the lower speed range and reduced maximum power in that the existing camshaft and the setting time are modified by welding on naturally hard material and higher pistons, if necessary by Complement the existing pistons, are built in. Cited publications: German Patent Nos. 3a0 921, 648 807, 165 355, 66 267; Transactions of the ASME magazine, July 1947, p. 455; Hugo Güldner, The design and calculation of internal combustion engines and gas-fired systems, 3rd edition, Berlin 1922, p. 48a.