DK162853B - PROCEDURE FOR IMPROVING THE PROCEDURAL REGULATION WITH A STAMP COMBUSTION ENGINE AND A STAMP COMBUSTION ENGINE FOR EXERCISING THE PROCEDURE - Google Patents

Description

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DK 162853 B

The present invention relates to a method for improving the walking regularity of a three or multi-cylinder piston combustion engine in stationary operating mode, at which the indicated mean pressure of at least one 5 cylinder is changed, as well as a piston combustion engine for carrying out the method.

The control and monitoring of the operation of such piston-combustion engines, for example with diesel engines 10, has so far been carried out by monitoring the speed of the output shaft or shaft of a machine driven by the engine. The control itself is effected by means of changes in the amount of injection for all injection pumps, which in a particular cycle are connected to the individual cylinders.

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This known form of control takes into account and controls the constant of the rpm in such a way that it changes in the same way for all cylinders by changing the injection amount, assuming that the injection rate is equal in all cylinders.

Publication C33 / 85 of the Institution of Mechanical Engineers Conference 1985-2, pages 15-24 (Mechanical Engineering Publications Limited, London), with the contribution "Vehicle Condition Monitoring and Fault Diagnosis", shows a measurement model and the possibility of detecting faulty cylinders in a multi-cylinder diesel engine in a crank stationary state. RPM fluctuations are thereby considered by Fourier analysis.

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Another type of speed control is described in EP Publication No. 0 113 510, in which, relative to a found operating speed on the motor shaft, the rotational speed deviation and the time difference for a predetermined rotational angle interval are measured, after which this rotational deviation is assigned cyclically to a predetermined range of ignition.

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2, and a control acts against the rotational speed deviation on the injection time of the allocated cylinders to achieve an equal rotational speed oscillation over all pivot angle intervals measured on the motor shaft.

5 Such adjustments hardly take into account torsional oscillations in the participating axle system and the effect of these oscillations on the driven assemblies, which torsional oscillations are thus not taken into account in the known speed control so far.

Cases are provided where this type of steering is insufficient and in which the differences in the rotational speed of the shafts or the resulting angular velocity changes within a rotation can be disruptive. For example, this torque fluctuation produced by irregular walking can be disruptive to diesel powered electric machines such as generators. In such systems, for example, powered by 20 slow-moving two-stroke diesel engines (for example, 80-120 rpm), the first and second-order torque oscillation frequency (single or double rotational frequency) is close to the generator's electric e-frequency . Thereby, it may occur that the amplitudes of torsional oscillations of these orders are dynamically enlarged several times, whereby the mechanical shaft system in interconnected operation as a whole oscillates against the rigid interconnected network, which can, for example, lead to power commuting. In an independent grid (island operation) this can again lead to flicker.

It is therefore the object of the invention to overcome the disadvantages stated and to ensure a substantially improved smooth running time for a piston-combustion engine.

This object is achieved by a method of 35

DK 162853 B

3, the method according to the invention is characterized in that the torsional vibrations of the drive shaft system are minimized in at least one order, the 5 torsional vibrations being measured in the first process step on the drive shaft or on a shaft with a drive shaft kinematically with a torsional vibration measuring device, the measured torsional vibrations in the second method. 10 is subjected to a Fourier analysis for torsional oscillations, correction factors for changing the indicated mean pressure for at least two cylinders are determined in a third process step in a unit of calculations from the found values and 15 positions of the torsional oscillation amplitudes and from comparison with predetermined torsional oscillations induced by the single cylinders, and the correction factors in a fourth process step cause a change in the amount of injection per injection from the injection pump on at least one of these two cylinders.

The invention further relates to a piston-combustion engine 25 of the type which is three- or multi-cylinder and wherein the indicated mean pressure of at least one cylinder is changed to improve the stationary regularity, which engine is used for carrying out the process.

The dependent claims relate to advantageous particular embodiments of the method, respectively, of the piston combustion engine.

The invention will be explained in more detail below with reference to the accompanying drawings, in which:

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FIG. 1 is a schematic representation of a six-cylinder diesel engine with generator and a system according to the invention to improve the operation of the diesel engine; Figures 2, 2A, 2B and 2C each schematically show a six-cylinder powered ship diesel engine with an on-board generator for a grid on board and a plant according to the invention for improving the diesel engine's regular operation; 3 shows a pole diagram of the first-order torsional oscillations of the crankshaft in a six-cylinder diesel engine or a shaft driven by the diesel engine, respectively.

A six-cylinder two-stroke diesel engine 1 with a supercharger unit 11 and a shaft 12 drives a generator 2, whereby the rotor of the generator, as shown in the drawing, is mounted directly on the extension of the shaft 12 or the rotor shaft can be coupled to the shaft 12 of the diesel engine 1. Their amplitude and angular position, respectively, are continuously measured with a torsion oscillator 3 at the shaft end 123 and fed to a Fourier analyzer 4. In the Fourier analyzer 4, the Fourier division of the torsional oscillations is performed in the joints of different order.

First, injection pumps 61, 62, 63, 64, 65, 66, each belonging to a cylinder 161, 162, 163, 164, 165, 166, inject a predetermined amount of fuel that is mutually identical into the cylinders. As soon as the diesel engine has reached the 30 stationary operating state, a switch 45 is closed and the Fourier analyzer's Fourier signals arrive at an injection pump controller 5 which includes a calculator, such as on the basis of the first and second order joints, e.g. a cranking method explained by FIG. 3, and when compared to a desired state, determine:

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5 1. Which cylinder or cylinders 161, 162, 163, 164, 165, 166 cause the emergence of torsional turns of this order, and 5 2. What correction of the amount of injection into which cylinders are needed to minimize torsional turns of this order.

For example, since the crankshaft star method is a simple approximation method, the minimization of torsional turns is iterative, that is, in several cycles or steps. At each step, correction signals are generated which are fed to the respective injection pump 61, 15 62, 63, 64, 65, 66. Due to the correction, a new stationary state of the diesel engine 1 is set.

Once reached, the torsional oscillations are again measured and analyzed in a new control cycle, and on the basis of the analysis results, other correction signals are generated and the 20 torsional oscillations are further minimized.

As a rule, a favorable stationary operating condition is obtained with minimal, non-interfering torsional oscillations, for example, of the first and second order or of higher orders in the shaft 12 25 after some control cycles of the type described.

The control cycle thereby extends advantageously over the duration of several duty cycles (revolutions) of the diesel engine 1. This ensures that the stochastic changes of the induced cylinder mean pressure from ignition to ignition in the individual cylinders 161, 162, 163, 164, 165, 166 only negatively affects the torsional vibration signal to be utilized.

For example, for detecting the torsional oscillations a device commercially available under the designation is suitable

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6 "Angular Incremental Encoder", Type G 70 from Litton Company. For example, an injection pump suitable for changing the amount of injection is disclosed in DE Publication No. 31 00 725.2-13.

Five Fourier analyzers are also known and are commercially available (for example, CAT 2515 from the company Genrad).

A two-stroke diesel engine 1 in FIG. 2 with six cylinders 161 to 166 pulls through a shaft 22 a ship screw 7. The other 10 end of the shaft 22 of the diesel engine is connected by a coupling 18 to an exchange gear 8 which pulls a hydraulic pump 81. This pump 81 is part of a hydrostatic gear which together with a hydrostatic motor 82 forms a closed hydraulic pressure medium circuit. The supply of this circuit with hydrostatic pressure medium, for example oil, is conducted through a low pressure station 83 which contains a pressurized reservoir, a feed pump, an overflow line with an overflow valve, filter and so on. The hydrostatic motor 82 pulls through an axle 89 an electric generator 9. The shaft 89, and thus the generator 9, is monitored by a measurement sensor 84, from which the measured actual value is passed to a revolution controller 85 and in which the actual value is compared. with the predetermined desired value. The generator 9 supplies the electrical energy to the ship's electrical grid 100. In the case of deviations between actual and desired value, the amount of pressure medium flowing through the hydrostatic motor 82 is thereby changed as the control signals are fed to a setting means in the motor 82 through a signal line 86. In this example, a torque oscillation meter 3 measures the torsion oscillations in the shaft of the generator 9. The correction signals applied to injection pumps 61, 62, 63, 64, 65, 66 are determined in the same manner as described above for the system of FIG. 1. The torsional vibrations produced by the diesel engine 1 are partially transferred through the hydrostatic circuit to the engine 82 and to the generator shaft.

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In the embodiment shown in FIG. 2A diesel shaft system 1, the shaft 17 of the diesel engine 1 pulls through the clutch 71 and the shaft 73 the adjustable ship screw 72. The shaft 17 'of the diesel engine on the other side of the diesel engine pulls through a gear 91 the generator 9 which supplies the electric current to the ship network 100. , respectively, their amplitude and angular position, are measured with the torsional oscillation meter 3 on the shaft of the generator 9 and fed continuously to the Fourier analyzer 10. In the Fourier analyzer 4, the Fourier division of the torsional oscillations is carried out at the joints of different order and then a comparison is made with the prior given desired values. The correction signals for changing the amount of injection for the injection pumps 61, 62, 63, 15 64, 65, 66 are determined in the injection pump control 5, which comprises a calculator, on the basis of, for example, the first and second order joints, for example by the crank star method, which is explained by FIG. Third

20 In the embodiment of FIG. 2B diesel diesel system pulls the shaft 17 of the diesel engine through the clutch 71 shaft 73 with the adjustable ship screw 72. The gear 92 is connected to the shaft of the diesel engine 1 as a side gear, and pulls through a clutch 94 the generator 9. The generator 9 supplies electrical energy to the ship network 100. Also here, the torsional oscillations in the shaft of the generator 9 are continuously determined with the torsional oscillation meter 3 in terms of amplitude and angular position, and passed to the Fourier analyzer 4. Here, too, the division of the torsional oscillations takes place in different order in the Fourier analyzer 4 and then the comparison with predetermined desired values.

In the embodiment shown in FIG. 2C diesel diesel system shaft 17 of diesel engine 1 pulls through shaft 71 shaft 73 with adjustable ship screw 72. In this system, gear 93 is pulled directly from shaft 73 and in turn pulls through the shaft 73.

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8 the generator 94 generator 9. The generator 9 supplies electrical energy to the ship network 100. Again, the amplitude and angular position of the torsional vibrations are measured continuously and fed to the Fourier analyzer 4. In the Fourier analyzer 4, the Fourier division of the torsional oscillations occurs as a result of different order and then a comparison with predetermined desired values takes place. The determination of the correction signals for the injection pumps 61, 62, 63, 64, 65, 66 can be effected at systems 2Ά, 2B, 2C in the same manner as described in FIG. First

The improvement of the operation of the diesel engine 1 and of the powered generator requires that the diesel engine be substantially in a steady state of operation. This is generally the case for marine diesel plants and even more so for marine diesel systems with adjustable ship screw for extended periods of time at sea. For example, the hydraulic or mechanical gears 91, 92, 93 manage to keep the rpm of generator 9 constant within certain rpm limits, as may be the case with ship propulsion systems with non-adjustable ship screw. As a ship has several generators on board, the group drawn by the propulsion diesel engine is only engaged when sailing on the high seas, where the propulsion motor runs at a constant speed.

It is also possible to put the rotor of the generator 9 directly on the shaft 73, and dimension the generator for a specific speed which corresponds to the speed of the diesel engine in continuous operation. Then the gear 93 and the clutch 94 would fall into, for example, a system as shown in FIG. 2C. In this case, the torsional oscillations would be measured with the torsional oscillation meter 3 on shaft 73 or shaft 17.

35 By means of FIG. 3, the crank star method is explained to determine the correction factors for correcting the injection amount to minimize the first-order torsional fluctuations. The crank star method assumes, for example, the simplifying assumption that 9

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5 - the indicated cylinder mean pressure of a cylinder does not deviate by more than 5% from the desired value, the perturbation amplitude grows linearly with the perturbation and the phase remains the same, 10 - the measured perturbation, that is, a measured torsional oscillation, can be minimized by correcting the the indicated mean cylinder pressure in two or in particular a cylinder, that is, the disturbance is caused by the relevant cylinders.

The engine ignition is assumed to be 1, 6, 2, 4, 3, 5. In the pole diagram 19, the calculated first order torsional vibration vectors 191-196 in the shaft of a six-cylinder engine 20 are plotted punctured for all six cases where one of the cylinders produces a 5% reduction of the indicated cylinder agent pressure. These vectors form the so-called first order correction crunch star. The ends of these vectors lie on a circle whose center point M is not 25 in the pole diagram's fulcrum, but is offset by a vector 190. This vector 190 corresponds to the torsional oscillation vector of the ideal, i.e., fully equalized taotor.

Subtracting this vector 190 from each of the individual vectors 191-196 30 gives the offset correction crank loss 191'-196 '.

This calculated crank star 191'-196 'now serves to determine the corrections of the indicated cylinder mean pressure in one or more cylinders.

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For example, if a torsional oscillation S (amplitude and phase) is measured on the shaft and the vector is plotted into the offset correction crank loss star, then S lies between two vectors in the offset correction crank loss star, in our example between the vectors 191 'and 196', or coincides with the direction of one of the vectors 191 ^ 196 ^ The division of the amplitude vector S into the two vectors S! and S6 in the direction of the two vectors in the correction cranking star are thus interpreted as the interference from the two cylinders 1 and 2. The correction cranking star is based on the assumption of a smaller output from the disturbed cylinder, but since the cylinder can also provide too much, division is calculated on the correct vector basis.

This basis is a pair of the vectors Zx, Z6, Z3 and Z4. Thus, the correction factor for the two cylinders in a park combination appears directly from the correction crank loss star.

In fact, one or more cylinders may be disturbed. The simplified assumption that attributing each disturbance to, for example, two cylinders usually makes it necessary to implement the minimization iteratively, that is, in several steps. A single correction factor before only one cylinder appears when the vector of the measured disturbance coincides with one of the vectors 191 '-196'.

Although the calculation of the correction factors for the first-order perturbations here for the sake of clarity is explained by a graphical example, it is useful to find the correction factors in the injection pump control 5 by calculation, i.e. numerically. By analogy, the correction factors for minimizing torsional oscillations can also be determined.

35 The described form of minimization of torsional oscillations has in practice proved very favorable. The invention is in the

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11 are limited to the described examples, but include any methods for improving the piston combustion engine operating regularity in which correction factors affecting the indicated mean pressure are found otherwise.

The invention was explained by means of examples relating to diesel engines. In principle, the method is applicable to any piston combustion engine with volumetric fuel supply to the cylinders.

Claims (10)

A method of improving the walking regularity of a three or multi-cylinder piston internal combustion engine in stationary operating mode, at which the indicated mean pressure of at least one cylinder is changed, characterized in that the torsional shaft system's torsional oscillations are minimized by at least one order, the drive shaft or on a shaft (12, 22) connected to the drive shaft with a torsional oscillation measuring device (3), the measured torsional oscillations in another method step are subjected to a Fourier analysis for torsional oscillations, correction factors for changing the indicated mean pressure for at least two cylinders are determined in a third process step in a unit of calculation based on the values and phase positions of the torsional oscillation amplitudes and from comparison with predetermined torsional oscillations induced by the individual cylinders (161, 162, 163, 164, 165, 25 166) and correction factor in a fourth process step, a change in the amount of injection per injection from the injection pump (61, 62, 63, 64, 65, 66) by at least one of these two cylinders. Method according to claim 1, characterized in that the first and second order torsional vibrations are minimized. 35 Method according to one of claims 1 and 2, characterized in that the minimization of the torsional oscillations occurs iteratively in several steps. Method according to one of Claims 1 to 3, characterized in that the torsional oscillations are measured at the shaft (123) of an electric generator (2, 9; 91, 92, 93) driven directly by the shaft of the piston combustion engine (1). (12) or through a gear (8, 81, 82, 83) or which is an extension (123) of the piston 10 (12) of the combustion engine (1) and that by minimizing the torsional shaft of the generator shaft (123, 89) also the torsional oscillations in the piston-combustion engine shaft (12). Piston internal combustion engine of the type which is three or 15 cylinders and wherein the indicated mean pressure of at least one cylinder is altered to improve the operating regularity of the stationary motor for use in the method of claim 1, characterized in that: that the piston combustion engine (1) has a device 20 (3) for measuring the torsional oscillations in the drive shaft or in a further shaft coupled thereto, a Fourier analyzer (4), to which the torsional oscillation measurement values are applied, a calculating unit (5) from which phase and amplitude of the joints in the Fourier analysis and from the comparison with 25 predetermined torsional oscillations induced by the cylinders (161, 162, 163, 164, 165, 166), determine fuel injection rate correction signals for at least one cylinder and one injection device ( 61, 62, 63, 64, 65, 66) to which the correction signals are fed, which injection device injectes it onto the g round of the correction signals, the fuel quantity in the cylinder changed, thus changing the indicated cylinder mean pressure for this cylinder. 6. Piston-combustion engine according to claim 5, characterized in that it has 3-12 cylinders. DK 162853 B 14 Piston internal combustion engine according to claim 5 or 6, characterized in that it is a slow-moving two-stroke diesel engine. 5 Piston-combustion engine according to one of claims 5-7, characterized in that an axial extension of the shaft of the piston-combustion engine is designed as a shaft for an electric generator and that the device (3) for measuring 10 of the torsional vibrations is arranged in such a way that it measures the torsional oscillations of the generator shaft (123). Piston combustion engine according to one of claims 5-8, characterized in that a gear (8, 81, 82, 83; 91, 92) is arranged between the main shaft (12) of the piston combustion engine (1) and a side shaft (89). 93) and that the device (3) for measuring torsional oscillations is arranged so as to measure the torsional oscillations (9, 89). 20 Piston internal combustion engine according to any one of claims 5-9, characterized in that a common unit of calculation exists for the Fourier analysis of the torsional oscillations for comparison with predetermined desired values and for determining the correction signal for changing the injection device (61, 62, 63, 64, 65, 66) injection course.