WO2008012006A2

WO2008012006A2 - Reciprocating-piston internal combustion engines

Info

Publication number: WO2008012006A2
Application number: PCT/EP2007/006313
Authority: WO
Inventors: Franz Brauers
Original assignee: Franz Brauers
Priority date: 2006-07-22
Filing date: 2007-07-17
Publication date: 2008-01-31
Also published as: WO2008012006A3; DE102006033960A1

Abstract

Proposed are novel reciprocating-piston internal combustion engines in which, in operation, the kinetic energy of the oscillating masses is buffered as potential energy at the dead centers at which the braking and acceleration forces are greatest, in order to thereafter be utilized for re-accelerating the oscillating masses. In this way, the majority of the acceleration and braking work is imparted no longer by the mechanism but by gas forces, so that the friction power losses are reduced and the mechanical efficiency is improved. In addition, the engines can all be designed to have extremely long strokes, such that their thermal efficiency is also improved on account of reduced wall heat losses. A more favourable efficiency results overall from these measures. In some engine concepts, the buffered potential energy can be discharged from the engine in the form of compressed air and stored in a compressed air accumulator, so that when using the internal combustion engine in a vehicle, braking energy buffering is possible. The stored compressed air can likewise be used to start the engine.

Description

description

Title: Reciprocating internal combustion engines

State of the art

Reciprocating internal combustion engines in which the kinetic energy of the oscillating masses is trapped on the respective opposite side by the build-up of potential energy are already described in DE-PS 409 919 and in particular in DE 199 23 021, but these predominantly use "exotic" Crank mechanisms, which have not been successful in practice so far.

Likewise already concepts are with

Brake energy intermediate storage in the form of compressed air has been proposed (for example DE 35 18 031, DE 199 46 711). These are very expensive, z.T. External compressors and a second drive unit are used to bring back the stored compressed air energy when accelerating the vehicle back to the drive.

In DE 25 50 567 an internal combustion engine with integrable pressure generation has been proposed, but not primarily to intercept the kinetic energy of the piston and also

".;"1_4- ,, - J- ^ l ~ i ~ -.- - l- ~~ - ^ Ti - ^• 1 - J -I-. , uxvui. tΛin »-ILG L / J. UL. Λ.C j. i, c uy um.) Lui Dj. ciuociici yxciwxouucuoμcιj.oπt! l to harness Lilly. The machine there also uses a crank mechanism, which causes a prolonged residence time of the working piston in Zündumkehrpunkt, as can be made possible with the Gelenkpleuel described in DE 30 30 615. To extend the residence time of the working piston in Zündumkehrpunkt a further variant is proposed in this document.

Besehrθibung

The motor according to claim 1 Fig.l.

The two working pistons 1 of a 2-cylinder 4-stroke internal combustion engine are interconnected to form a common unit 2 and have on their back another piston, which runs in a cylinder 3, in which only air is compressed and which is not fired.

By this arrangement it is achieved that during operation, the kinetic energy of the oscillating piston assembly 2 is cached in the lower reversal point in pressure-volume work. After opening the exhaust valves, the piston assembly 2 is accelerated back again by the built-pressure pad. The oscillating mass is thus no longer braked and accelerated by the mechanics as in conventional reciprocating engines, but in each case by the gas forces in the reversal points. In the upper reversal point, this is done by always one of the two working cylinders is in the compression stroke.

Since the size of the kinetic energy to be stored depends on the rotational speed of the engine, an actuating unit 6 is provided on the pneumatic cylinder 3, with which the compression of this cylinder and thus the height of the resulting final pressure can be adjusted according to the speed of the engine. Furthermore, the engine has two laterally arranged next to the engine block crossheads 4 and a crank mechanism 5, which is located above the cylinder head.

By the crossheads is achieved that the piston assembly 2 moves only linear. As a result, the high side forces and the associated friction losses, which occur in conventional engines on the piston skirt, shifted into the crossheads and can be better reduced there due to the oil pressure lubrication. Furthermore, the crossheads allow an extremely long-stroke design of the cylinder. This has the advantage that due to the favorable surface / volume ratio in the ignition point, when pressure and temperature and thus also the wall heat losses are greatest, the heat losses decrease significantly and a better thermal efficiency results. This is also improved by the fact that the working gas can remain due to the compression on the opposite side to the lower reversal point in the cylinder and not as in conventional engines already 40 ° before UT must be omitted.

The interconnection of the three pistons to a unit 2 also causes the largest part of the gas exchange work in the working cylinders and the compression work in the compressed air cylinder 3 drivetrain subtracted from the expansion work and only the difference is effective only on the crank mechanism. This also reduces the frictional losses, because these are proportional to the amount of the attacking forces.

Apart from the fact that the engine can be designed with a conventional arrangement of the crankshaft below the working piston, the "overhead" arrangement has some advantages: - Extension of the residence time of the working piston 1 in the Zündumkehrpunkt and thus isochoric combustion and increasing the speed, especially in diesel mode possible.

Reduction of the piston acceleration in the mechanically and thermally highly loaded Zündumkehrpunkt, which is important for a long-stroke engine with in principle higher average piston speed.

The connecting rods are loaded mainly on train and hardly on pressure and can be designed accordingly lighter.

The compressed air in the compressed air cylinder 3, which may well be up to 15 bar at high speeds, can be omitted via a valve 7 on this cylinder and transferred into a compressed air storage 8.

This acts as an engine brake, and thereby kinetic energy of the vehicle can be collected and stored in the sliding and braking operation of a vehicle. When starting and accelerating the vehicle compressed air can be released back into this cylinder via the valve 7 and thus support the drive.

The stored compressed air can also be used to start the engine and to realize start / stop driving.

The valve 7 is electromagnetically controlled. Since only air is switched at moderate pressures and temperatures, it can be small and light. If the compressed air accumulator 8 receives compressed air (braking operation), it opens as soon as pressure equality exists between compressed air cylinder 3 and compressed air accumulator 8. The actuator 6 is set to maximum compression.

If the compressed air accumulator 8 delivers compressed air (start-up operation), it opens in or shortly after TDC and can remain open in the event of a great need for acceleration until shortly before UT, before the venting valve 10 opens. When starting the engine, this makes sense in any case, so that the engine quickly comes to idle speed and the starting emissions remain low. The actuator 6 is set to minimum compression in these two cases.

The vent valve 10 on the compressed air cylinder 3, performed in Figure 6 as a mere lock in the cylinder wall, on the one hand has the function to admit new air of atmospheric pressure (or pre-compressed from a turbocharger) in this cylinder when compressed air for the purpose of

On the other hand, when for accelerating the vehicle compressed air was discharged from the memory 8 in the cylinder 3 back to direct the residual pressure in the air cylinder 3 on the turbocharger, so that it responds faster.

Since the compressed air transferred into the compressed air accumulator 8 is compressed and accordingly heated (by far over 200 ^° C.), the compressed air accumulator 8 is thermally insulated against its environment to the outside. Furthermore, the heat losses from the compressed air reservoir 8 out can be kept low, that in this a heat storage 9 (eg steel wool) is installed, which causes the temperature in the Compressed air accumulator 8 only increases moderately when filled with fresh compressed air.

Even without the options Brake Energy Buffering and Start / Stop, the engine has improved overall efficiency, mainly due to the reduced friction losses. However, additional fuel can be saved via these two additional functions, in particular in short-distance driving.

Since in this engine, three pistons are connected together to form a unit 2, the oscillating mass is relatively large, and for smooth operation, a mass balance makes sense. To compensate for the mass forces 1st order can be switched on the crank mechanism 5 in a known manner a rotating at a single speed balancing shaft. If the second-order inertia forces are to be compensated, at least one additional shaft, which revolves at twice the speed, would be necessary.

But there is another way.

If the motor is provided away from the crossheads 4 on both sides both above and below the power pistons with a crank gear 5 and 5 '(see Figures 2, 3 and 4) and both have the same connecting rod ratio and are the rotating masses on both crank gears the same size, then a complete mass balance (mass forces 1st and 2nd order, mass moments do not occur) can then be achieved if at each crank drive rotating at a single speed balancing shaft is turned on.

This situation is shown in Fig.3. The oscillating mass of the piston assembly 2 acts on two opposing crank mechanisms 5 and 5 ', to each of which a rotating at a single speed balance shaft 11 is turned on. As a result, the inertial forces of the 2nd order are automatically compensated, because the imbalance, which is caused by the einknickenden crank drive on the one hand, is always compensated straight by the resulting imbalance on the opposite crank mechanism.

Such a second crank mechanism would be very expensive for a second cylinder.

However, replacing the pneumatic cylinder 3 of FIG. 1 by two further working cylinders, so that one obtains a 4-cylinder internal combustion engine (see FIG. 2), this can be fully balanced despite the large oscillating mass, and the second crank mechanism. 5 'Also, the valve control for the second cylinder head can still be tapped so that it does not require a belt.

With the known ignition sequence expanding and sucking on one side and compressing and exhausts on the other side, the oscillating piston assembly 2 is always just tossed between two gas cushions a free piston, and the mechanical losses are minimal.

Further advantages result from the cross-heads 4 made possible long-stroke expediency.

In Fig 4a / b, an 8-cylinder internal combustion engine in plan and side view is shown, in which two blocks, each with four arranged in a rectangle cylinder are arranged opposite to each other (see DE 199 23 021 claim 15). The Firing order is such that always two diagonally opposite cylinders of one side ignite simultaneously, suck in the adjacent cylinders of this side and compress or evacuate the axially opposite cylinders.

As a result, the entire piston assembly 2, as well as the centrally arranged piston push rods 12, always symmetrically applied with expansion force, and it will be avoided lateral forces on the piston 1. Further, since all gas exchange work as well as a part of the compression work is subtracted from the expansion work, and only the difference in the crank mechanism is effective, the friction losses are minimal.

This machine can be fully balanced with a second opposing crank mechanism by a push rod 12 is guided through both cylinder blocks, which act on the above the cylinder heads arranged crossheads 4 and 4 ', to which the crank mechanisms 5 and 5' each with a simple speed rotating balancer shaft 11 are connected according to Figure 3.

The engines described so far have the disadvantage that they have unusual dimensions (they build relatively long) and on the other hand, that they can only be installed horizontally, because the crank mechanisms are located respectively on the cylinder heads.

In the following, therefore, modifications are described in particular of the concept shown in Fig.l, with the same or at least similar features and performance features, which, however, no longer or no longer have the aforementioned limitations to the extent. The in Figs. 5a and 5b illustrated 2-cylinder 4-stroke internal combustion engine has instead of crossheads via a motor housing 20 mounted Anlenkpleuel 14, which acts centrally on a yoke 17, on which also the two working piston 1 via the Kolbenpleuel 15 and the Kurbelpleuel 16 attached are.

The Anlenkpleuel 14 is designed by its radius forth so that the Kolbenpleuel 15 swivel in their cylinders only small and thus can take place a long-stroke design of the cylinder, with the advantages already mentioned. Furthermore, the Anlenkpleuel 14 causes the extensive linear guide of the working piston 1, so that the mixing friction on the piston skirt is only small and instead caused by the crank mechanism lateral forces are absorbed mainly in one of lubricated with pressure oil rotary motion on the yoke 17.

Centrally below the Anlenkpleuel 14 is a mechanical spring 18 which intercepts the oscillating mass at the lower reversal point and provides for their rear acceleration, so that even in this engine, the rear acceleration does not have to be applied by the crank mechanism and thus a more harmonious torque curve results.

Note: Previous engines with Gelenkpleuel have the disadvantage that thereby increase the oscillating masses and only in 2-stroke process all 360 ° crank angle in TDC they are intercepted by the compression gas pressure.

However, if two cylinders operating in 4-stroke mode are interconnected via a common Anlenkpleuel with spring element below it, so on the one hand, the increase in the On the other hand, it is no longer absorbed by the mechanics but by potential energy every 180 °, ie in all piston reversal points.

Instead of this mechanical spring 18, another element may be used to temporarily store the kinetic energy of the piston assembly, e.g. turn a compressed air cylinder or an electrical method. In electrical or electromagnetic methods, the intermediate energy storage in batteries or in capacitors can be done.

With a mechanical spring is

However, brake energy buffering is not possible. However, in order to be able to intercept different kinetic energies at different speeds, a device can be provided with which the bias of the spring is adjusted accordingly.

A modification of the principle of Figs. 5a and 5b is shown in FIG.

The Anlenkpleuel is hereby extended to a mounted in the engine block 20 rocker 19, and the storage element for temporary storage of the E _k i _{n of} the oscillating masses of the two working pistons located at the same height with these. This results in a very compact engine, which, when the storage element is designed as a compressed air cylinder, this counteracts as opposed to the piston 1 reciprocating piston even their oscillating mass, which should improve the running smoothness improving, so that a balance shaft is possibly superfluous. reference numeral

working piston

piston assembly

Air Cylinder

crossheads

crankshaft

actuator

Valve

Compressed air storage

heat storage

vent valve

balancer shaft

Piston push rods

articulation connecting rod

Kolbenpleuel

Kurbelpleuel

yoke

feather

seesaw

motor housing

Claims

Dr. Franz Brauers 12Patentansprüche

1. 2-cylinder 4-stroke internal combustion engine in a row arrangement with crosshead gear (4), characterized in that the two working pistons (1) to a common unit (2) are connected together and this opposite a device for storing the kinetic energy the oscillating masses is in potential energy.

2. 4-cylinder 4-stroke internal combustion engine with two rows of two cylinders, which are the same axis, with all four pistons are connected together to form a common unit (2) and the output via lateral crossheads (4), characterized characterized in that at the two cylinder heads each have a crank mechanism (5) and (5 ^λ ) is located with the same connecting rod ratio and attached to each crank mechanism for complete balancing of the machine rotating at a single speed balancing shaft.

3. 8-cylinder 4-stroke internal combustion engine with two blocks of four cylinders arranged in a rectangle, which are coaxially opposite, with all eight pistons to a common unit (2) are connected together, characterized in that the output via centrally guided between the cylinders guided push rods (12), which act on each one above the cylinder heads arranged crosshead (4) and (4 ') with crank mechanisms (5) and (5 ¹ ), both of which have the same connecting rod ratio and at which full balancing of the machine per a single speed rotating balancer shaft is mounted.

4. 2-cylinder 4-stroke internal combustion engine in a row arrangement, characterized in that the two working pistons (1) act on a common yoke (17) which is connected by a Anlenkpleuel (14) with the wall of the motor (20) in that the working pistons (1) are largely linearly guided in their cylinders, and that a device for storing the kinetic energy of the oscillating masses in potential energy is located underneath the Anlenkpleuels (14).

5. 2-cylinder 4-stroke internal combustion engine in a row arrangement, characterized in that the two working pistons (1) act on a common yoke (17) which is guided over a motor block (20) mounted rocker (19) which has at its other end a device for storing the kinetic energy of the oscillating masses in potential energy.

6. Internal combustion engine according to claims 1, 4 and 5, characterized in that the device for energy storage from a cylinder (3) in which a pump piston runs, consists, in which the energy is built up in the form of compressed air and which with an actuating unit ( 6), so that the compression ratio of this cylinder can be variably set depending on the rotational speed of the engine.

7. Internal combustion engine according to claims 1, 4 and 5, characterized in that the device for energy storage consists of a mechanical spring (18) whose bias is variable according to the speed of the motor.

8. Internal combustion engine according to claims 1, 4 and 5, characterized in that the device for

Energy storage from any other method, e.g. an electrical or a magnetic, and the energy in corresponding memory, e.g. Batteries or capacitors is cached.

9. internal combustion engine according to claim 1, characterized in that the crank mechanism (5) is located above the working cylinder on the cylinder head, such that the crank mechanism runs with reverse kinematics and thereby the residence time of the piston is extended in Zündumkehrpunkt.

10. Internal combustion engine according to claim 1, characterized in that the crank mechanism (5) is mounted off-center, such that the lateral forces produced at the crossheads (4) become minimal.

11. internal combustion engine according to claims 1, 4, 5 and 6, characterized in that in the compressed air cylinder (3) compressed compressed air is introduced into a pressure accumulator (8), which then acts as an engine brake so as to operate the internal combustion engine in a vehicle To buffer braking energy.

12. Internal combustion engine according to claims 1, 4, 5, 6 and 11, characterized in that the stored compressed air is returned during startup and acceleration of the vehicle back into the compressed air cylinder (3).

13. Internal combustion engine according to claims 1, 4, 5, 6 and 11, characterized in that still existing residual pressure in the compressed air cylinder (3) at the end of the expansion on the Turbine is routed to a possibly attached turbocharger, such that it starts faster and the turbo lag is reduced.

14. Internal combustion engine according to claims 1, 4, 5, 6 and 11, characterized in that the stored compressed air is used to start the engine and to operate the vehicle in start / stop mode.

15. Internal combustion engine according to claims 1, 4, 5, 6 and 11, characterized in that in the compressed air reservoir (8) has a heat storage (9), e.g. made of steel wool, which absorbs the with the in-cylinder (3) compressed and thus hot compressed air entrained heat and partially releases the outflow of compressed air, so that the compressed air reservoir (8) heated less and less heat losses are.