WO2000012825A1

WO2000012825A1 - Diesel rammer

Info

Publication number: WO2000012825A1
Application number: PCT/EP1999/005366
Authority: WO
Inventors: Nikodemus Heinz; Stefan Mewes; Winfried Scheid
Original assignee: Delmag Maschinenfabrik Reinhold Dornfeld Gmbh & Co. I.K.
Priority date: 1998-08-27
Filing date: 1999-07-27
Publication date: 2000-03-09
Also published as: CA2341680A1; DE19838838A1; CN1314963A; EP1108094A1; JP2002523657A

Abstract

According to the invention, the composition of the air-fuel mixture in a diesel rammer is controlled depending on the momentary working conditions of said diesel rammer. For this purpose, different sensors, especially a fall height sensor, are provided, said fall height sensor consisting of individual position detectors (64-i) which are mounted spaced from the cylinder (12) in axial direction.

Description

Diesel ram

The invention relates to a diesel ram according to the preamble of claim 1.

Such diesel rams have been in use on construction sites for many years to drive piles or other ramming material such as sheet piling and the like into the ground. With such diesel rams, the percussion pistons typically have a weight between 1 t and 5 t, rammed material can be rammed into the ground quickly and relatively inexpensively.

The rams operate under manual control of the fuel supply. A ram driver determines the amount of fuel required by visually checking the progress of driving in and the jump height of the percussion piston. The general rule here is that if the floor is too soft, some of the impact energy must be absorbed by the cylinder itself, since the hammer has only a limited stroke and strikes the end wall of the cylinder if the floor is too soft. Conversely, it can happen with very hard ground that the percussion piston jumps very high, so that there is also a risk of damage to the diesel ram or it can even be expected that the percussion piston will shoot out of the upper end of the cylinder in an uncontrolled manner, which leads to serious accidents .

The present invention is therefore a diesel ram according to the preamble of claim 1 are formed so that the amount of fuel supplied per stroke is automatically dosed in accordance with the respective operating requirements.

This object is achieved by a

Diesel ram with the features specified in claim 1.

In the diesel ram according to the invention, the amount of fuel required for the next field is derived from the momentary dynamics of the field just processed. As already indicated above, the jump height of the percussion piston can be used to estimate the hardness of the subsurface and thus the further advance of the material to be expected when the percussion piston hits the impact piece. Comparable information is provided by the movement of the hammer on the last stroke. The speed at which the percussion piston moves past a predetermined measuring point after the mixture has been ignited is also a measure of the impact force obtained in each case. Further parameters that can be taken into account when metering the fuel are the temperature in the combustion chamber or the temperature reached in the outlet and / or the pressure prevailing in the combustion chamber. A measure of the completeness of the combustion of the fuel is the soot content in the exhaust gas.

With simple requirements for the quality of the automatic fuel metering, only one of the aforementioned sensors can be used. In the case of more complex metering, it is also possible to use several of the sensors mentioned in claim 1 and to use their output signals in a predetermined hierarchy to regulate the amount of fuel or to use them weighted in a predetermined manner together to meter the amount of fuel. It goes without saying that the amount of air brought to the combustion can be controlled analogously in order to set the desired ramming result. Overall, according to the invention, the composition of the fuel / air mixture ignited in the combustion chamber is controlled as required.

Advantageous developments of the invention are specified in the subclaims.

The development of the invention according to claim 2 is advantageous with regard to a particularly precise metering of the fuel emissions.

The development of the invention according to claim 3 is advantageous when there is only a limited amount of time available for the fuel dispensers, but the amount of fuel per cycle should nevertheless be adjusted within wide limits.

The development of the invention according to claim 4 allows the intensity of the next stroke to be controlled briefly when fuel has already been added to the combustion chamber.

The development of the invention according to claim 5 is advantageous with regard to a robust and reliably working position measurement of the percussion piston even under tough operating conditions.

According to claim 6, a single detector can be used simultaneously for position measurement and for speed measurement.

The development of the invention according to claim 7 allows It is to distribute the various position detectors on the cylinder of the diesel ram in such a way that no unacceptable local weakening of the mechanical strength results.

In those cylinder areas in which the cylinder does not have to withstand large internal pressures and predominantly has management tasks, the position detectors can also be arranged according to claim 8, which is mechanically and also simpler in terms of the wiring.

The development of the invention according to claim 9 is also preferred with regard to simple mounting of the position detectors and simple cabling.

With the development of the invention according to claim 10 it is achieved that the detector support bar is stable over long times and does not affect the movement of the percussion piston.

The development of the invention according to claim 11 allows a position measurement of the percussion piston without mechanical intervention in the cylinder. This further development is therefore particularly suitable for retrofitting an automatic fuel metering on existing diesel rams.

The development of the invention according to claim 12 makes it possible to provide information about the expected jump height of the percussion piston at an early stage. The earlier the expected jump height of the percussion piston is known, the more time is available for dosing the amount of fuel.

With the training according to claim 13 it is achieved that an expected too high jump height is automatically recognized.

In the case of a diesel ram, the compression or the available combustion air is reduced if the percussion piston shows an excessive jump height.

In the case of a diesel ram, the system automatically monitored when the expected jump height of the percussion piston could lead to a safety problem.

According to claim 16, this automatic detection of a situation which is questionable for safety reasons can be used to immediately stop driving forces acting on the percussion piston and to prevent a subsequent impact cycle, even if a quantity of fuel has already been introduced into the combustion chamber for the next cycle.

The development according to claim 17 is advantageous on the one hand with regard to a reliable connection of the movable wall segment to the cylinder, as is desired for normal operation of the diesel ram. At the same time, however, the movable wall segment can also be quickly moved into its open position.

According to claim 18, a mechanically particularly reliable and simple position transmitter for the percussion piston is obtained.

According to claim 19, the output signal of the force sensor can be corrected in such a way that an overall linear signal which varies with the position of the percussion piston is obtained. With the development of the invention according to claim 20, the advantage is obtained that the density of soot particles obtained during combustion is measured undiluted. In addition, the density of the soot particles is measured at a point at which there is a high flow rate both when the combustion gases are expelled and when fresh combustion air is drawn in, so that the light barrier is cleaned well.

The development of the invention according to claim 21 is also advantageous with regard to good self-cleaning of the light barrier.

With the development of the invention according to claim 22, a well laminar flow is obtained in the vicinity of the optical members of the light barrier.

The further development of the invention according to claim 23 enables the influence of the various sensors on the fuel metering to be predefined in accordance with the importance attached to them.

According to claim 24, the weighted composition of the various error signals can be carried out in a simple manner.

With a diesel ram according to claim 25, such actual values that are already stable and well in the vicinity of their target value can be completely removed from the control loop or their influence on the control can be removed and then the control can be refined taking other parameters into account, for example more stable after adjustment Jump heights the further metering of the fuel quantity depending on the concentration the soot particles entrained in the combustion gases and / or depending on the CO content of the combustion gases.

Irregularities in the operation of diesel rams can also result from irregularities in the distribution of a constant amount of fuel in the combustion chamber. In the case of a diesel ram according to claim 26, the fuel is supplied to the fuel trough formed in the upper side of the impact piece through lines, not as a free jet. The fuel is then distributed largely independently of the possibly unstable flow conditions in the combustion chamber.

The lubricants that are used in diesel rams are at least partially burned during a combustion process. The development of the invention according to claim 27 makes it possible to take into account the contribution to driving the piston obtained by the combustion of the lubricants.

In the case of a diesel pile driver, the penetration of the pile material into the ground is continuously monitored. From the per stroke (given energy) received

Feed of the pile can be concluded from the hardness of the areas of the soil that have just been pierced.

With the development of the invention according to claim 29, it is easy to obtain a precise position of the pile to the end of the pile driving. The cooperation of the feed encoder with the end of the pile, in particular with a striking hood placed on the latter, ensures that the feed measurement is not caused by those occurring during the pile driving Vibration is influenced, since the feed measurement can take place in those times in which the pile material stands still between successive blows.

The development of the invention according to claim 30 is advantageous in terms of keeping jerky movements and vibrations away from the actual transducer. When the pile is struck, the flexible measuring means is relieved and gently adjusts itself to the new position of the pile under later bias.

With a diesel ram according to claim 31, the entire history of ramming a pile can be documented. In this way a clear profile of the local hardness of the soil is obtained.

In the case of a diesel pile driver according to claim 32, one has an overview of the total amount of fuel emitted during the driving of the pile. The hardness of the various layers of the earth can also be seen from this. The stored injection quantities can also serve as initial values for the adaptation of the fuel quantity to the local hardness of the ground when ramming another pile in the immediate vicinity.

According to claim 33, a more precise measurement of the local hardness of the soil and a continuous dynamic determination of the current load-bearing capacity of the pile are obtained. If desired, the ramming can be terminated after a specified load-bearing capacity has been saved, thus saving overall ramming time.

The development of the invention according to claim 34 allows documentation of the development of the load-bearing capacity of the ramming material over the entire ramming time. This also provides a clear overview of the hardness and resilience of the penetrated layers of earth and, for example, allows ramming to be stopped in a hard layer of earth below which a softer layer lies again when a further pile to be rammed in the neighborhood.

The invention is explained in more detail below on the basis of exemplary embodiments with reference to the drawing. In this show:

Figure 1: an axial section through a diesel ram and a schematic diagram of a device for automatic dosing of the pro

Cycle amount of fuel supplied depending on the respective operating conditions;

Figure 2: a development of the inner surface of the cylinder of the diesel ram shown in Figure 1;

FIG. 3 shows a block diagram of a position and speed detector working together with the percussion piston of the diesel hammer;

FIG. 4: shows a block diagram of a circuit which provides an output signal corresponding to the expected jump height of the percussion piston;

Figure 5 is a block diagram of an error signal unit used in the automatic fuel metering device; FIG. 6 shows a block diagram of a circuit for forming an overall error signal from a large number of individual error signals assigned to different operating parameters;

FIG. 7: a block diagram of a control stage of the automatic fuel metering device of the diesel ram;

Figure 8: a similar representation as Figure 2, but in which a modified diesel ram is shown.

FIG. 8: a representation similar to FIG. 1, but in which a variant of the metering of the fuel and the supply of the fuel to the combustion chamber is shown;

FIG. 9: a representation similar to FIG. 2, but in which a modified diesel ram is shown; and

Figure 10: a similar representation as Figure 1, but in which a modified diesel ram is shown.

In Figure 1, 10 schematically denotes a diesel ram. It has a cylinder 12 which is open at the top and closed at the bottom by an end wall 14. The end wall 14 has a central opening 16, in which a shaft section 18 of an impact piece, indicated overall by 20, is guided. The striking piece 20 has a piston section 22 which carries sealing rings 24 and runs in the lower section of the cylinder 12. At the end of the shaft section 18 located outside the cylinder 12, a striking section 26 is provided, the lower end face 28 of which is spherically curved.

The striking piece 20 works together with the top of a striking hood 30, which is shown in dashed lines in FIG. 1 as well as a pile 32 carrying it, which is to be rammed into the ground.

In the interior of the cylinder 12, a percussion piston, designated 34 overall, is guided. This has a piston section 36 with sealing rings 40. A weight section 44 having large axial dimensions lies above the piston section 36. The weight of the percussion piston 34 is typically in the range between 1 t and 5 t.

The percussion piston 34, together with the percussion piece 20 and the cylinder 12, delimits a combustion chamber 46. The combustion chamber 46 is connected to the ambient atmosphere via a working nozzle 48. The working nozzle 48 has an axis that rises obliquely upwards and serves to supply fresh combustion air to the combustion chamber and to remove combustion gases from the combustion chamber, as is customary in two-stroke diesel engines.

An injection nozzle 50 is inserted into the lower portion of the peripheral wall of the cylinder 12. This is connected via a 2/2 solenoid valve 52 to the outlet of a fuel feed pump 54, which draws in from a fuel reservoir 56. The fuel delivery pump 54 is preferably one by a hydraulic motor

58 driven feed pump. The hydraulic motor 58 is fed from the hydraulic network of a vehicle (not shown) carrying the diesel ram 10. To limit the delivery pressure of the fuel delivery pump 54, a pressure relief valve 60 is provided, which leads back from the delivery side of the delivery pump 54 to the reservoir 56.

The solenoid valve 52 is controlled by a control unit 62, which operates as a function of a plurality of sensors.

The control unit 62 works primarily as a function of the instantaneous position of the percussion piston 34. In order to be able to determine this, position detectors 64-1, 64-, which follow one another axially and in the circumferential direction, are at regular intervals along the helical line in the wall. 2, ... 64-i inserted flush

The position detectors 64 can, for example, work according to the eddy current principle, as shown in FIG. A sensor coil 66 is connected to an operating circuit 68, through which a sensor coil 66

AC is maintained. Depending on whether or not the sensor coil 66 is facing a section of the percussion piston 34, the sensor coil 66 is damped differently. This can be determined by the operating circuit 68, and this is constructed overall so that it provides an output signal corresponding to the damping of the sensor coil 66 at its output. This output signal shows the juxtaposition of the percussion piston 34 with a large value and a non-juxtaposition of the percussion piston with a low value. piston 34. The speed at which the percussion piston 34 passes the sensor coil 66 can be derived from the steepness of the signal edges lying between the two output voltage values. The output signal of the operating circuit 68 is provided on the one hand on an output line 70 and on the other hand is given to a differentiating circuit 72. This thus represents a signal on a further output line 74, which corresponds to the piston speed.

The various position detectors 64 -i are connected to inputs of the control unit 62, as indicated for some of the position detectors. By evaluating the output signals of the position detectors 64 -i, the control unit 62 can thus determine where the lower edge of the percussion piston 34 is located and at what speed it is moving up or down. The position detectors 64 thus together form a combined position and speed sensor 76 which cooperates with the percussion piston 34.

It is understood that the position detectors 64-i do not only cooperate with the lowermost edge of the piston section 36, as initially assumed above for the sake of simplicity in the description of the operation of the position detectors 64 -i. The upper edge of the piston section 36 and the lower edge of the piston section 38 also cooperate with the position detectors in an analogous manner. In order to improve the resolution of the displacement measurement, these edges are offset against the lower edge of the piston section 36 in such a way that these further control edges of the percussion piston 34 cooperate with the position detectors 64 -i each time the percussion piston 34 rotates by one third or two thirds of the Distance between two neighboring position detectors 64 -i moved on. The control unit 62 can recognize which of the control edges has just actuated a position detector, taking into account the last received output signals.

A light barrier unit, generally designated 78, is also attached to the working nozzle 48 of the cylinder 12. This comprises a transmitting part 80, which emits an IR laser beam clocked at a predetermined frequency, and a correspondingly clocked receiving part 82, which receives the laser beams.

The transmitting part 80 has an optical output part 84, e.g. a quartz part which has a dome-shaped polished end surface projecting into the working socket 48. Correspondingly, the receiving part 82 has an optical input part 86, which can also be made of quartz and which has a spherical end surface projecting into the working connection 48. Output part 84 and input part 86 are positioned so that their two

End faces 86, 90 lie with their base line on the inner surface of the work nozzle 48. In this way, the end faces 86, 90 are exposed to the currents in the working nozzle 48 and are constantly flushed out. The density of the soot particles in the combustion gases can be measured from the weakening of the laser beam running from the transmitting part 80 to the receiving part 82.

To increase the sensitivity, the axis of the laser beam can also be aligned more parallel to the axis of the work nozzle 48, for which purpose, for example, the receiving part 82 can be moved to the position indicated by the dashed line in FIG. 1 and the axes of the transmitting part 80 and the receiving part 82 can be tilted accordingly. The free end of the working nozzle 48 also carries a CO sensor 88, a CH sensor 90 and a temperature sensor 92. These are arranged in the flow path of the gases flowing through the working nozzle 48 and measure the content of the combustion gases in carbon monoxide or unburned hydrocarbons and Temperature of the fresh combustion air sucked into the combustion chamber 46 and of the combustion gases emerging from the combustion chamber 46. The outputs of the sensors 88, 90 and 92 are connected to further inputs of the control unit 62.

Another temperature sensor 94 is arranged in the lower section of the combustion chamber 46. This can be a pressure test inserted into the peripheral wall of the cylinder 12. For some applications it is also sufficient to couple a temperature sensor to the outside of the peripheral wall of the cylinder 12 in the area of the combustion chamber.

In the lower section of the combustion chamber 46, a pressure sensor 96 is also provided, which is embedded pressure-tight in the outer wall of the cylinder 12 and which measures the pressure curve when the combustion air is compressed, when the fuel / air mixture burns off and when the combustion gases expand. The temperature sensor 94 and the pressure sensor 96 are connected to further inputs of the control unit 62.

Furthermore, a relief opening 98 is provided in the lower region of the combustion chamber 46. This is connected to a buffer tank 102 via a throttle 100 and a 2/2 solenoid valve 101. The normally closed solenoid valve is controlled by the control unit 62. A position sensor, generally designated 104, is provided for the striker 20. This includes a force sensor 106, which is embedded in a deeper, axially parallel blind bore 108 of the end wall 14. A sensor spring 110 engages on the force sensor 106 and rests with its upper end on the underside of the piston section 22. The output signal of the position sensor 104 is also passed on to the control unit 62, which outputs this output signal according to a predetermined characteristic, for example by means of the digitized one

Output signal addressable correction memory can be formed, linearized.

FIG. 2 illustrates the position of the various position detectors 64-i, the CO sensor 88, the CH sensor 90, the temperature sensor 94 and the pressure sensor 96 as well as the working nozzle 48 and the relief opening 98 in development of the inner surface of the cylinder 12.

Figure 4 shows how the output signals of the various

Position detectors 64 can be used to predict the jump height of the percussion piston 34 starting shortly after the fuel / air mixture is ignited.

The various position detectors 64-1, 64-2, etc., which in addition to the position signal also provide a speed signal, as described above with reference to FIG. 3, are connected to different inputs of an extrapolator 112.

After the mixture has been ignited, the extrapolator 112 first receives a signal from the lowest position detector 64-1, which indicates that the lower edge of the percussion piston is just passing this position detector. Further The extrapolator 112 receives information from the position detector 64-1 about the speed at which the percussion piston 34 passes the detector. From these two values, the extrapolator 112 can determine how high the percussion piston 34 is likely to rise according to a predetermined algorithm (free fall) or from stored values determined by experiment. A short time later, the extrapolator 112 receives a similar pair of signals from the position detector 64-2. From this, the extrapolator can determine a new probable jump height of the percussion piston 34, it being able to derive information about the frictional forces acting on the percussion piston 34 from the deviation between the first pre-calculation and the second pre-calculation. The extrapolator can then provide this information to another

Use extrapolation of the anticipated jump height that extrapolator 112 makes when it receives its output signal combination from position detector 64-3.

In this way, an output signal is obtained at an output H of the extrapolator 112, which initially very quickly but still has a certain error, but then increasingly reproduces the expected jump height of the percussion piston 34. It goes without saying that the output signal of the extrapolator 112 can then also be used to recognize when the percussion piston 34 has reached its full respective jump height.

The extrapolator 112 outputs an output signal corresponding to the instantaneous speed of the percussion piston 34 at a further output V.

The position detectors 64 -i and the extrapolator 112 permit the expected impact time in an analogous manner starting from the top dead center of the percussion piston 34 of the percussion piston 34 on the striking piece 20. A corresponding signal is provided at an output Z.

According to FIG. 4, the extrapolator 112 works with one

Compression value memory 114 together, in which (in the case of new diesel rams determined by tests, later derived by self-learning from the output signals of the pressure sensor 96) those compression values are stored which are usually (averaging over a predetermined number of previous impact cycles, for example 50 cycles) is obtained when the percussion piston 34 passes a certain position detector 64 -i at a certain speed when climbing or falling. The amount of combustion air available for later ignition in the combustion chamber 46 can also be calculated directly from these compression values. A corresponding output signal is output at an output P of the extrapolator 112.

In the manner described above, the movement of the percussion piston 34 and the amount and the pressure of the combustion air in the combustion chamber 46 can thus be determined well before the next mixture is ignited. So you have time to dose the amount of fuel in a way that is desired with regard to the desired driving performance, the desired mixing ratio and with regard to environmental considerations. The addition of fuel can be extended over a longer period of time, which favors a reproducible supply of the fuel. In the known diesel rams, on the other hand, a predetermined fuel volume is always delivered into the combustion chamber 46 within a short period of time shortly before the bottom dead center of the percussion piston 34 is reached. since its lower edge mechanically operates an operating lever of a fuel injection pump directly.

The output signals from sensors 78 and 88 to 96 and the output signal of extrapolator 112 can be taken into account when metering fuel:

An analog / digital converter 118-i is provided for each of these sensors, which are denoted neutral in FIG. 5 by 116 -i. The output signal of the A / D converter 118-i is connected to the one input of a digital subtraction circuit 120-i. The latter receives its second input signal from a memory cell 122-i of a computer 124 belonging to the control unit 62. This memory cell contains the setpoint for the measured variable under consideration. An error signal E-i associated with the measured value under consideration is obtained at the output of the subtracting circuit 120-i. The unit formed by components 116-122 is referred to below as an error signal generator and bears the reference symbol 126-i.

The extrapolator 112 and the position detectors 64-i connected to it likewise form a sensor digitization unit, corresponding to the connection in series of a sensor 116-i and an A / D converter 118-i in the sense of FIG. 5.

FIG. 6 shows how the output signals of the various error signal generators 126-i can be weighted to form an overall error signal, the weighting, which can be changed over time, being used to specify which of the measured variables in the control the Geraisch composition more, which should contribute less. For this purpose, a total of 128 error signal combination circuit designated 128 contains multipliers 130-i, one of whose inputs are connected to the outputs of the various error signal generators 126-i. The other inputs of the digital multipliers 130-i are connected to memory cells 132 -i of the computer of the control unit 162 already mentioned above in connection with the memory cells 124 -i. Memory cells 132-i contain changeable multiplication factors. The

Output signals of the multipliers 130-i are combined by a digital adding circuit 134 to form an overall error signal E.

A weight control circuit 136, which may be formed by a programmable microprocessor, also receives the output signals of the error signal generators 126-i. The weighting control circuit 136 currently determines, with consideration of the error signals E-i, according to predetermined criteria, with what weight the individual

Error signal generators 126-i should contribute to fuel quantity control. Thus, the weighting control circuit 136 can stipulate that if a constant jump height of the striking piston 34 has been determined over a plurality of cycles, further working cycles of the diesel rammers 12 are operated with predominant consideration of environmental parameters, that is to say with a view to minimizing the soot particle release. Conversely, if the weighting control circuit 136 detects dangerous operating conditions, it is preferable to use the corresponding measured value size for metering the fuel quantity, in which case the other measured values are put aside. For example, the weighting control circuit 136 can, for example, if it detects that the impact piece 20 has been moved so far in a stroke that the underside of its piston Cut 22 comes dangerously close to the top of the end wall 14, make the amount of fuel for the next stroke cycle exclusively or predominantly as a function of the output signal of the position sensor 104 by setting the multiplier memory cell 132 -i associated with this measured value accordingly high.

As can be seen from FIG. 1, a flap 138 is provided in the lower region of the circumferential wall of the cylinder 12 for extreme hazards. This can be pivoted about schematically indicated hinges 140 and is normally held in a position via locking parts 142 in which it sits tightly in the peripheral wall of the cylinder 12. The closing parts 142 have predetermined breaking points 144 which can be opened by electrically controllable detonators 146. These are operated by the control unit 62.

The exit of the step height extrapolator is used to determine the imminence of an extreme hazard

112 connected to a digital comparator 148 (see FIG. 4). Its second input is connected to a memory cell 150 of the computer 124 contained in the control unit 62, in which there is a maximum jump height at which damage to the diesel ram or the impact piston 34 being thrown out of the cylinder 12 must be expected. The comparator 148 then generates an output signal if the jump height predicted by the extrapolator 112 is greater than the maximum tolerable jump height stored in the memory cell 150.

As shown in FIG. 7, a four-digit counter 152 is incremented by the output signal of the comparator 148. If the impact piston 34 is thus ascertained four times that the maximum permissible jump height is likely to be exceeded, a signal is generated at the output of counter 152, by means of which an amplifier 154 detonates the detonators 146. As a result, the interior of the cylinder 112 is immediately relieved of pressure.

As can also be seen in FIG. 7, the step height output signal H of the extrapolator 112 is also fed to the control terminal of a monostable multivibrator 156 which is controllable in its pulse length. The output signal is used via an AND gate 158 and a power amplifier 160 to control the electromagnet of the solenoid valve 52. A quantity of fuel is thus fed into the combustion chamber 46, as is necessary so that the percussion piston receives the same desired height in the next stroke cycle.

The second input of the AND gate 158 has the output signal of the comparator 148 inverted by an inverter 162. The fuel supply to the combustion chamber 46 is thus interrupted as long as an impermissibly high jump height is predicted in the current working cycle.

The output signal of the comparator 148 also serves to trigger a monostable multivibrator 164, the output signal of which actuates an alarm device 168 shown as a loudspeaker via an amplifier 166.

A relief control circuit 174 is acted upon by the error signal generator 118 -P assigned to the pressure in the combustion chamber. This is only activated by the computer of the control unit 62 if more fuel has already been dispensed into the combustion chamber 46 than according to The latest information about the operating conditions of the diesel ram is necessary for the next impact cycle, for which the output signal of the monostable multivibrator 156, which is inverted by a further inverter 175, is characteristic. The relief control circuit 174 controls the magnet of the solenoid valve 101 via an AND gate 176, the second input of which is connected to the output of the inverter 175, and via an amplifier 176. A portion of the compressed air in the combustion chamber 46 is then released into the buffer container 102, where it is no longer available for combustion purposes. The fuel already supplied to the combustion chamber 46 is thus burned under poorer combustion conditions, which results in a reduction in output for the current impact cycle.

In the modified exemplary embodiment according to FIG. 8, the fuel is supplied directly to a fuel trough 178 formed in the striking piece 22 via a radial fuel channel 180 formed in the striking piece, which is in the vicinity of the fuel trough

178 contains a check valve 182, which opens in the direction of the fuel well 178, blocks in the opposite direction. The fuel channel is like out of the

Drawing can be seen angled and has an axial section containing the check valve 182 and a radial section leading to the circumferential surface of the piston section 22. The piston section 22 of the impact piece 20 now has a larger axial dimension, so that the fuel channel 180 is in all positions tightly connected to an axially extending fuel discharge slot 184, which is formed in the circumferential wall of the cylinder 12 and with a fuel supply opening 186 communicates. The solenoid valve 52 is connected to the fuel feed opening 186. In this way, a smooth supply of the fuel to the fuel well, which is independent of flows in the combustion chamber and is uniform in the circumferential direction, is obtained.

The exemplary embodiments described above have in common that the metering of the amount of fuel supplied to the combustion chamber 46 takes place automatically and without human intervention in accordance with different criteria. You get a more effective and gentle ramming of the pile.

The exemplary embodiment according to FIG. 9 differs from that according to FIGS. 1 and 2 in that those of the position detectors 64 -i, which are located in the colder region of the cylinder 12, in which no high pressures occur, are arranged on a carrier strip 188. The position detectors, which are arranged on the carrier strip 188, have the same axial distance as the position detectors arranged on a helical line in the lower region of the cylinder 12. The carrier strip 188 is made of a heat-resistant plastic material which has little friction with metal. The entire support bar is in one

Recessed groove 190, which is machined into the inner surface of the cylinder. This facilitates the mounting and wiring of the position detectors 64 -i.

The further modified exemplary embodiment according to FIG. 10 initially differs from that according to FIG. 1 in that instead of a plurality of position detectors 64-i distributed in the axial direction, a single position sensor 198 is provided, which is mounted on a rod 200 attached to the upper end of the cylinder 12 the Axis of the cylinder 12 is arranged lying above the upper end of the cylinder so that it is not reached by the percussion piston 34 under all normal operating conditions. The position sensor 198 works according to the radar principle, the waves being either light, in particular infrared radiation, electromagnetic waves in the MHz and GHz range or ultrasonic waves. Such position sensors are known per se to the person skilled in the art. The control unit 62 continuously evaluates the output signal of the position sensor 198 and can in turn derive a speed signal by differentiation. The evaluation of the position signal and the speed signal, as emitted by the position sensor 198, is again carried out analogously to that described above with reference to FIGS. 1 to 7.

Another difference of the diesel ram 10 according to FIG. 10 to that according to FIG. 1 is that the solenoid valve 52 is brought into the open position by the control unit 62 for a constant period of time. To do this, the controllable clock generator 156 is simply connected to a constant signal source which specifies the width of the pulse generated. The control of the fuel quantity takes place in the diesel ram according to FIG. 10 in that a variable throttle 202 is inserted into the connecting line between the solenoid valve 52 and the injection nozzle 50 and is adjusted by a servomotor 204. The latter is controlled again by the control unit 62.

As shown in FIGS. 1 and 10, the cylinder 12 carries a plurality of lubricant nozzles 206 distributed at a higher point in the circumferential direction, which are connected to the outlet of a 2/2 solenoid valve 208. This is also done by the control unit 62 actuates and connects the lubricant nozzles 206 to the outlet of a lubricant pump 210, which draws in from a lubricant reservoir 212, for a predetermined period of time selected with regard to a required amount of lubricant. To limit the lubricant pressure, a pressure relief valve 214 is provided which leads back from the outlet of the lubricant pump 210 to the reservoir 212.

From the opening time for the solenoid valve 208, which he himself specifies, the control unit 62 knows which amount of lubricant has been delivered into the interior of the cylinder 12 by the lubricant nozzles 206 at the given delivery pressure of the lubricant pump 210. Experience has shown that part of this amount of lubricant burns during the next combustion cycle. Knowing the amount of lubricant, the control unit 62 can then subtract the energy contribution made during the later combustion from the burning portion of the amount of lubricant from the amount of fuel required to achieve the desired jump height of the percussion piston 34.

It goes without saying that the opening time of the lubricant nozzles 206 can be set in phases so that these lubricants are applied to the outer surface of the percussion piston

Spray 34 (either during the upward stroke and / or the downward stroke), and / or can also be placed so that the lubricant nozzles 206 spray lubricant directly onto the cylinder wall when the percussion piston 34 is located above the lubricant nozzles 206. Depending on the phase position in which the lubricant nozzles 206 are activated, different partial quantities of the injected quantity of lubricant will burn. The control unit 62 also takes this into account. As can be seen from FIGS. 1 and 10, a feed encoder, generally designated 216, works together with the striking hood 30. This comprises a flexible measuring part 218, the upper end of which is fastened to an arm 220 carried by the striking hood 30. The measuring cable 218 is wound on a drum 224 in its lower section. Their angular position is measured by a resolver 226, which is connected to an input of the control unit 62. The drum 224 is kept constant via a magnetic slip clutch 228

Torque load maintained, which is driven by a hydraulic or electric motor 230. In this way, the measuring cable 218 is normally kept under constant tension. If the impact hood 30 is struck, a sag initially forms in the measuring cable 218, so that the rest of the feed encoder 216 is not subjected to an abrupt load. During that time, which then passes until the next blow (spinning upwards and falling down again of the impact piston 34), the motor 230 has sufficient over the slip clutch 228

Time to tension the measuring rope 218 again. The now changed output signal of the resolver 226 shows exactly how much the case 32 was rammed into the earth during the impact considered. The control unit 62 takes over the output signal of the resolver 226 as a reference value at the first impact and then knows after each further impact how far the tip of the pile 32 lies below the surface of the earth.

As can be seen from FIGS. 1 and 10, a memory 232 is assigned to the control unit 62. In this, the control unit 62 stores the injected fuel quantity and the output signal of the resolver 226 as a function of the number of the stroke that has just been carried out. The load capacity of the pile can be calculated later (or the control unit 162 in real time) from these values, since the quotient of the amount of fuel injected and the further advance of the pile obtained with this amount of fuel is a measure.

By outputting the data held in the memory 232 or the updated development of the load-bearing capacity of the pile, one obtains a meaningful log of the entire ramming process and thus a proof of the quality of the work carried out. Up to now, such proof of quality could not be provided or only with great effort.

As can be seen from the above description of exemplary embodiments, a diesel pile driver according to the invention thus enables driven material to be driven into the ground with low energy consumption, low environmental pollution (soot, exhaust gases) and documented quality.

Claims

claims

1. Diesel ram with a cylinder (12), with an impact piece (20) guided in a lower end wall (14) of the cylinder (12), with an impact piston (34) guided in the cylinder (12), which with the impact piece (20) cooperates and, together with the latter and the cylinder (12), delimits a combustion chamber (46) which communicates with the surroundings via a working opening (48) provided in the circumferential wall of the cylinder (12) and which is connected via a fuel supply (50 to 56) Fuel is supplied, characterized in that at least one sensor from the following group of sensors is carried by the cylinder (12): a position sensor (76) which cooperates with the percussion piston (34), a speed sensor (which cooperates with the percussion piston (34)) 76), a temperature sensor (94) thermally coupled to the combustion chamber (46), a pressure sensor (96) connected to the combustion chamber (46), a particle communicating with the working opening (48) sensor (78), a CO sensor (88) connected to the working opening (48), a CH sensor (90) connected to the working opening (48) and a position sensor (104 ); and that a control unit (62) is provided which controls the composition of the fuel / air mixture generated in the combustion chamber (46) as a function of the output signal of at least one of these sensors.

2. Diesel ram according to claim 1, characterized in that the control unit (62) the fuel delivery time of fuel supply (50 to 56) controls.

3. Diesel ram according to claim 1 or 2, characterized in that the control unit (62) controls the fuel delivery rate of the fuel supply (50 to 56).

4. Diesel ram according to one of claims 1 to 3, characterized in that the control unit (62)

Air volume in the combustion chamber (46) controls.

5. Diesel ram according to one of claims 1 to 4, characterized in that the position sensor (76) has a plurality in the axial direction of successive position detectors (64-i).

6. Diesel ram according to claim 5, characterized in that the position detectors (64-i) in addition to a position signal additionally provide a speed signal, for which purpose they e.g. are each connected to a differentiating circuit (72) which generates a speed signal from the edges of the output signal of the connected position detector (64-i).

7. Diesel ram according to claim 5 or 6, characterized in that at least part of the position detectors

(64-i) is arranged along a helical line on the cylinder (12).

8. Diesel ram according to one of claims 5 to 7, characterized in that at least one upper

Group of position detectors (64-i) is arranged along a surface line of the cylinder (12).

9. Diesel ram according to claim 8, characterized in that at least a portion of the along a surface line arranged position detectors (64-i) is arranged on a detector support bar (188) inserted into the inner surface of the cylinder (12), preferably inserted flush.

10. Diesel ram according to claim 9, characterized in that the detector support strip (188) is made of a temperature-resistant plain bearing material, in particular of a heat-resistant plastic which has low friction on metal.

11. Diesel ram according to one of claims 1 to 4, characterized in that the position sensor (198) is a contactless sensor with an end face of the percussion piston (34), in particular one according to the electromagnetic radar principle, the infrared radar principle or the ultrasound -Radar principle works.

12. Diesel ram according to one of claims 1 to 11, characterized by an extrapolator (112) which extrapolates the expected jump height of the percussion piston (34) from the output signal of the position sensor (76).

13. Diesel ram according to claim 12, characterized in that a step height comparator (72) which is acted upon by the step height output signal (H) of the extrapolator (112) responds when the expected step height of the percussion piston (34) is greater as a desired jump height.

14. Diesel ram according to claim 13, characterized by a communicating with the combustion chamber (46)

Servo pressure relief valve (101), which is controlled by the output signal of the step height comparator (72).

15. Diesel ram according to one of claims 11 to 14, characterized by a safety comparator (148) which is connected to the step height output signal (H) of the extrapolator (112) and provides an output signal when the latter provides an output signal which is larger as a maximum allowable jump height.

16. Diesel ram according to claim 15, characterized in that a movable wall segment (138) of the cylinder (12), which forms part of the limitation of the combustion chamber (46), is controlled into an open position by the output signal of the safety comparator (148) .

17. Diesel ram according to claim 16, characterized in that the movable wall segment (138) over

Predetermined breaking points (144) are connected to the cylinder (12) and can be broken open by detonators (146) which are ignited depending on the output signal of the safety comparator (148).

18. Diesel ram according to one of claims 1 to 17, characterized in that the position sensor

(104) has a feeler spring (110) which engages on the impact piece (20) and is supported on the cylinder (12) via a force sensor (106).

19. Diesel ram according to claim 18, characterized by a correction memory addressed with the output signal of the force sensor.

20. Diesel ram according to one of claims 1 to 19, characterized in that the particle sensor has a light barrier (78) which extends through a working nozzle (48) forming the working opening.

21. Diesel ram according to claim 20, characterized in that the light barrier (78) has a transmitting part (80) and a receiving part (82), the optical window elements (84, 86) extend into the interior of the work nozzle (48).

22. Diesel ram according to claim 21, characterized in that the window elements (84, 86) have spherical, preferably spherical end faces.

23. Diesel ram according to one of claims 1 to 22, characterized in that the various sensors (118-i) used to control the fuel combustion each have an associated error circuit (120-i, 122-i), which is a deviation of the respective sensor output signal provides a signal corresponding to a setpoint signal, and that an error signal combination circuit (128) is provided, which weights the output signals of the various error circuits (118-i) to form an overall error signal (E).

24. Diesel ram according to claim 23, characterized in that the error signal combination circuit (128) for each of the error signals received has a multiplier circuit (130-i) which, in addition to the corresponding error signal, receives the output signal of an associated multiplier memory (132-i) , and an adder circuit (134) which adds the output signals of the various multiplier circuits (130-i).

25. Diesel ram according to claim 24, characterized by a multiplier control circuit (136) which is supplied with the various error signals and which, depending on the latter, sets the contents of the multiplier memories (132-i).

26. Diesel ram according to one of claims 1-25, characterized in that the power supply device

(50 to 56) has a fuel feed channel (180) formed in the striker (20), which leads to a fuel trough (178) formed in the top of the striker (20).

27. Diesel ram according to one of claims 1-26, which has a lubricant supply device (206 to 214), characterized in that the control unit (62) controls the composition of the fuel / air mixture by the lubricant supply device ( 206 to 214) lubricant quantity taken into account.

28. Diesel ram according to one of claims 1-27, characterized by a feed transmitter (216) connected to the control unit (62), which emits signals corresponding to the current depth of penetration of a pile (32) into the ground.

29. Diesel ram according to claim 28, characterized in that the feed encoder (216) with the upper

End of the pile to be driven (32), in particular cooperates with a striker hood (30) placed on the upper end of the pile to be driven (32).

30. Diesel ram according to claim 29, characterized in that the feed encoder (216) has a flexible measuring means (218) which with a biased Aufwik- keltrommel (224) cooperates, which in turn is connected to an angle encoder (226).

31. Diesel ram according to claim 30, characterized by a memory (232) connected to the control unit (62), in which the output signals of the feed transmitter (216), which are present after a ramming cycle, are stored.

32. Diesel ram according to one of claims 1-31, characterized by a memory (232) connected to the control unit (62), in which the fuel quantities emitted in each case of a ramming cycle are stored.

33. Diesel ram according to one of claims 29-32, characterized in that the control unit (62) for each ram cycle from the fuel quantity and the feed of the pile (32) calculates the load capacity of the pile (32).

34. Diesel ram according to claim 33, characterized in that the control unit (62) stores the load-bearing capacity values of the rammed material (32) obtained in successive ramming cycles in a memory (232) as a function of the feed.