CA2486278C - A method in controlling an engine of a forest machine and a forest machine - Google Patents
A method in controlling an engine of a forest machine and a forest machine Download PDFInfo
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- CA2486278C CA2486278C CA2486278A CA2486278A CA2486278C CA 2486278 C CA2486278 C CA 2486278C CA 2486278 A CA2486278 A CA 2486278A CA 2486278 A CA2486278 A CA 2486278A CA 2486278 C CA2486278 C CA 2486278C
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- engine
- tree trunk
- forest machine
- trunk
- power
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23D—PLANING; SLOTTING; SHEARING; BROACHING; SAWING; FILING; SCRAPING; LIKE OPERATIONS FOR WORKING METAL BY REMOVING MATERIAL, NOT OTHERWISE PROVIDED FOR
- B23D59/00—Accessories specially designed for sawing machines or sawing devices
- B23D59/001—Measuring or control devices, e.g. for automatic control of work feed pressure on band saw blade
-
- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01G—HORTICULTURE; CULTIVATION OF VEGETABLES, FLOWERS, RICE, FRUIT, VINES, HOPS OR SEAWEED; FORESTRY; WATERING
- A01G23/00—Forestry
- A01G23/02—Transplanting, uprooting, felling or delimbing trees
- A01G23/08—Felling trees
-
- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01G—HORTICULTURE; CULTIVATION OF VEGETABLES, FLOWERS, RICE, FRUIT, VINES, HOPS OR SEAWEED; FORESTRY; WATERING
- A01G23/00—Forestry
- A01G23/02—Transplanting, uprooting, felling or delimbing trees
- A01G23/095—Delimbers
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- Life Sciences & Earth Sciences (AREA)
- Biodiversity & Conservation Biology (AREA)
- Ecology (AREA)
- Forests & Forestry (AREA)
- Environmental Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Control Of Vehicle Engines Or Engines For Specific Uses (AREA)
- Combined Controls Of Internal Combustion Engines (AREA)
Abstract
A forest machine and method in the control of an engine of the forest machine, which forest machine performs manipulation of tree trunks in such a way that the properties of the tree trunk subject to manipulating operations are determined by means of measurements of the tree trunk by the forest machine. Properties of a single tree trunk, determined at the beginning of its manipulation or to be updated during the manipulation of the tree trunk, are used to estimate, automatically in advance, power levels required by manipulating operations to be carried out on the tree trunk, before the tree trunk is subjected to the manipulating operations. On the basis of this, the function of the engine of the forest machine is automatically optimized by affecting the control parameters of the engine to provide the power levels by optimizing the efficiency of the engine.
Description
I
A METHOD IN CONTROLLING AN ENGINE OF A FOREST MACHINE, AND A
FOREST MACHINE
Field of the Invention The invention relates to a method in the control of an engine used as the primary power source for a forest machine. The invention also relates to a forest machine fitted to perform manipulation of tree trunks on a terrain.
Background of the Invention For harvesting, several forest machines are known which move on a terrain, such as harvesters. In the harvesters, a boom assembly is used, whose end is provided with a harvesting device, so-called harvesting head. By means of the harvesting head, an upright growing tree trunk can be cut, felled, delimbed, and further cut into logs of desired length. The tree trunks thus treated can be collected from the terrain aboard a moving forest machine equipped with a loading grapple, i.e. a forwarder. In the load space of the forwarder, the tree trunks are transported further, for example, to the side of a drivable forest road. There are also known combined machines in which the functions of a harvester and a forwarder have been combined, wherein the loading grapple may be replaced with a harvesting head that is also suitable for loading.
Alternatively, in the combined machine, it is possible to use several boom assemblies for harvesting and loading functions separately.
The primary power source used for forest machines of the above-mentioned type is typically a diesel engine which further rotates a hydraulic pump. The purpose of the hydraulic pump is to convert the mechanical energy produced by the diesel engine (rotational speed, torque of the engine) to hydraulic energy (volume flow, pressure produced by the pump). The hydraulic energy contained in the hydraulic system of the forest machine is further used to drive the actual hydraulic actuators of the forest machine. The hydraulically driven actuators, for example in a harvester, include hydraulic driving motors coupled to the wheels, hydraulic cylinders of the frame steering, hydraulic cylinders moving the boom assembly, as well as various hydraulic cylinders and motors included in the harvesting head. To the diesel engine used as the primary power source can also be coupled a number of various hydraulic DOCSTOR: 1953121\1 pumps which may be placed, for example, one after the other on the same driving shaft. Separate hydraulic pumps may be provided, for example, for the driving motors, the boom assembly, or the harvesting head.
In forest machines of prior art, the diesel engine is arranged to rotate the hydraulic pump/pumps substantially at a constant speed of rotation when the forest machine is in operation. The hydraulic pump driven at a constant speed of rotation is, in turn, arranged to provide either a given constant pressure level on the main line of the hydraulic system or to operate in a load-sensing manner, wherein the main line is always supplied with a pressure level and a volume flow according to the need. From the main line of the hydraulic system, hydraulic power is taken, for example, by the hydraulic actuators of the harvesting head via their respective control valves according to their respective needs.
In a situation in which the loading of the hydraulic system increases so high that the torque required of the diesel- engine driving the hydraulic pump exceeds the capacity of the diesel engine, the production of vol-ume flow by the hydraulic pump is reduced, if necessary, so that the hydraulic pressure in the main line of the hydraulic system can be maintained substantially on the desired level. The above-mentioned limitation in the power of the hydraulic system is typically implemented by changing the so-called control angle affecting the stroke volume of the hydraulic pump.
The speed of rotation of the diesel engine is conventionally kept con-stant with a mechanical governor in connection with the injection pump of the engine, to increase or decrease the fuel supply to the engine, if necessary. Consequently, the governor thus, in a way, increases or disengages the throttle of the engine to maintain a constant speed of rotation when the output of the diesel engine required by the hydraulic pump varies in different situations. During maximum output of the engine, said restriction of the power of the hydraulic system is used, if necessary; in other words, the volume flow (control angle) produced by the hydraulic pump is reduced to prevent a situation in which the torque of the diesel engine required by the hydraulic pump exceeds the maximum capacity of the engine, and the speed of rotation of the diesel engines may drop.
In forest machines, particularly harvesters, the total need for hydraulic power varies to a great extent according to the operation conducted by the forest machine at the time. In the case of the harvester, these func-tions can be roughly divided into, firstly, the movement of the harvester by driving on the terrain of the ground for logging and, when the har-vester stays still, the manipulation of tree trunks by means of the boom and the harvesting head connected to the same. Hereinbelow, refer-ence to these functions will be briefly made by the terms transport and harvesting.
Harvesting can be divided further into different steps which include, for example, the movement of the boom and the manipulation of a tree trunk by felling, cross-cutting and delimbing. With respect to the power demand,for example felling and cross-cutting' are'Toperations which will temporarily require a high hydraulic power, whereas the movement of the empty boom without a tree trunk in the grip of the harvesting head, the working machine staying still, will only require a relatively low hydraulic power.
To maintain the efficiency of the forest machine as high as possible, it is known to be important that, for example in harvesting, the speed of rotation of the diesel engine must not drop during the felling and cutting of trees which temporarily require high hydraulic powers, because this will significantly slow down the harvesting or affect directly on the qual-ity of the timber to be manipulated. In the worst case, a drop in the speed of rotation of the engine, for example, during cross-cutting, may cause a temporary deceleration in the sawing, and a cracking of the tree trunk in the longitudinal direction when under torque and sup-ported by the harvesting head, which reduces significantly the value of the trunk being manipulated. During delimbing, in turn, the feeding of the trunk at the harvesting head may, for example, stop at a particularly thick branch because of insufficient engine power. As a result, said manipulation operation is significantly slowed down or must be repeated.
A METHOD IN CONTROLLING AN ENGINE OF A FOREST MACHINE, AND A
FOREST MACHINE
Field of the Invention The invention relates to a method in the control of an engine used as the primary power source for a forest machine. The invention also relates to a forest machine fitted to perform manipulation of tree trunks on a terrain.
Background of the Invention For harvesting, several forest machines are known which move on a terrain, such as harvesters. In the harvesters, a boom assembly is used, whose end is provided with a harvesting device, so-called harvesting head. By means of the harvesting head, an upright growing tree trunk can be cut, felled, delimbed, and further cut into logs of desired length. The tree trunks thus treated can be collected from the terrain aboard a moving forest machine equipped with a loading grapple, i.e. a forwarder. In the load space of the forwarder, the tree trunks are transported further, for example, to the side of a drivable forest road. There are also known combined machines in which the functions of a harvester and a forwarder have been combined, wherein the loading grapple may be replaced with a harvesting head that is also suitable for loading.
Alternatively, in the combined machine, it is possible to use several boom assemblies for harvesting and loading functions separately.
The primary power source used for forest machines of the above-mentioned type is typically a diesel engine which further rotates a hydraulic pump. The purpose of the hydraulic pump is to convert the mechanical energy produced by the diesel engine (rotational speed, torque of the engine) to hydraulic energy (volume flow, pressure produced by the pump). The hydraulic energy contained in the hydraulic system of the forest machine is further used to drive the actual hydraulic actuators of the forest machine. The hydraulically driven actuators, for example in a harvester, include hydraulic driving motors coupled to the wheels, hydraulic cylinders of the frame steering, hydraulic cylinders moving the boom assembly, as well as various hydraulic cylinders and motors included in the harvesting head. To the diesel engine used as the primary power source can also be coupled a number of various hydraulic DOCSTOR: 1953121\1 pumps which may be placed, for example, one after the other on the same driving shaft. Separate hydraulic pumps may be provided, for example, for the driving motors, the boom assembly, or the harvesting head.
In forest machines of prior art, the diesel engine is arranged to rotate the hydraulic pump/pumps substantially at a constant speed of rotation when the forest machine is in operation. The hydraulic pump driven at a constant speed of rotation is, in turn, arranged to provide either a given constant pressure level on the main line of the hydraulic system or to operate in a load-sensing manner, wherein the main line is always supplied with a pressure level and a volume flow according to the need. From the main line of the hydraulic system, hydraulic power is taken, for example, by the hydraulic actuators of the harvesting head via their respective control valves according to their respective needs.
In a situation in which the loading of the hydraulic system increases so high that the torque required of the diesel- engine driving the hydraulic pump exceeds the capacity of the diesel engine, the production of vol-ume flow by the hydraulic pump is reduced, if necessary, so that the hydraulic pressure in the main line of the hydraulic system can be maintained substantially on the desired level. The above-mentioned limitation in the power of the hydraulic system is typically implemented by changing the so-called control angle affecting the stroke volume of the hydraulic pump.
The speed of rotation of the diesel engine is conventionally kept con-stant with a mechanical governor in connection with the injection pump of the engine, to increase or decrease the fuel supply to the engine, if necessary. Consequently, the governor thus, in a way, increases or disengages the throttle of the engine to maintain a constant speed of rotation when the output of the diesel engine required by the hydraulic pump varies in different situations. During maximum output of the engine, said restriction of the power of the hydraulic system is used, if necessary; in other words, the volume flow (control angle) produced by the hydraulic pump is reduced to prevent a situation in which the torque of the diesel engine required by the hydraulic pump exceeds the maximum capacity of the engine, and the speed of rotation of the diesel engines may drop.
In forest machines, particularly harvesters, the total need for hydraulic power varies to a great extent according to the operation conducted by the forest machine at the time. In the case of the harvester, these func-tions can be roughly divided into, firstly, the movement of the harvester by driving on the terrain of the ground for logging and, when the har-vester stays still, the manipulation of tree trunks by means of the boom and the harvesting head connected to the same. Hereinbelow, refer-ence to these functions will be briefly made by the terms transport and harvesting.
Harvesting can be divided further into different steps which include, for example, the movement of the boom and the manipulation of a tree trunk by felling, cross-cutting and delimbing. With respect to the power demand,for example felling and cross-cutting' are'Toperations which will temporarily require a high hydraulic power, whereas the movement of the empty boom without a tree trunk in the grip of the harvesting head, the working machine staying still, will only require a relatively low hydraulic power.
To maintain the efficiency of the forest machine as high as possible, it is known to be important that, for example in harvesting, the speed of rotation of the diesel engine must not drop during the felling and cutting of trees which temporarily require high hydraulic powers, because this will significantly slow down the harvesting or affect directly on the qual-ity of the timber to be manipulated. In the worst case, a drop in the speed of rotation of the engine, for example, during cross-cutting, may cause a temporary deceleration in the sawing, and a cracking of the tree trunk in the longitudinal direction when under torque and sup-ported by the harvesting head, which reduces significantly the value of the trunk being manipulated. During delimbing, in turn, the feeding of the trunk at the harvesting head may, for example, stop at a particularly thick branch because of insufficient engine power. As a result, said manipulation operation is significantly slowed down or must be repeated.
In the design of a forest machine, such as a harvester, the category of the size and capacity of the diesel engine used as the primary power source must be, in practice, selected so that the maximum output of the engine is sufficient for performing even the most power demanding operations, such as felling and cross-cutting, without recurrent unde-sired drops in the speed of rotation of the engine due to overloading.
The power source must also be capable of overcoming situations in which, for example, several hydraulic functions of the boom and the harvesting head are applied simultaneously during the manipulation of a heavy trunk. Consequently, the selection falls on a diesel engine whose power and torque properties provide an optimum compromise of the needs occurring in practice.
However, it is the maximum needs of the functions of the forest machine which primarily determine the size, nature and operating mode, to be kept substantially constant, for the engine to be selected for the forest machine; consequently, the arrangements of prior art are not operating in the range of the best efficiency when said engine is loaded with a partial load only. In practice, maximum output of the engine and the hydraulic system is required only occasionally, and during most of the operating time, a partial power substantially lower than the maximum capacity is applied. As a result, the efficiency and the specific fuel consumption of the engine are not optimal during typi-cal use of the forest machine according to arrangements of prior art.
The reason for the poor efficiency with partial loads can be understood in the following way. According to prior art, the engine is only aimed at keeping its speed of rotation at a constant level, corresponding to the respective valid need for the speed of rotation, wherein the power out-put of the engine, in practice, also follows the engine output required by the hydraulic pump at each time. However, since the engine is not subjected to any other control parameters representing more closely the on-going working situation or particularly the forthcoming situation, the readiness for power production is always at a maximum level in the arrangements of prior art. In other words, the engine is ready to pro-duce more power up to its maximum capacity only by increasing the throttle, if this is required by the power intake of the hydraulic pump from the shaft of the engine. In situations of partial loading, this readi-ness for power production which is unnecessarily high and redundant to be maintained, reduces the efficiency of the engine, because the 5 settings effective on the method of fuel supply into the engine are con-tinuously "maintained" optimal for the maximum output only. With par-tial outputs, these settings prevent the operation of the engine at an optimal efficiency, thereby increasing the fuel consumption of the engine, which is further manifested, for example, as an increase in the quantity of harmful exhaust gas emissions.
Furthermore, a mode of the forest machine is known from prior art, in which the driver of the harvester when in light work, for example work-ing in a stand marked for cutting and containing only relatively small trunks, manually adjusts the level of the constant speed of rotation used in the diesel engine to a lower constant level than normally in a situation when the maximum output of the engine is not likely to be used. This procedure reduces the engine's readiness for power pro duction and thereby reduces the total fuel consumption of the working machine, but it also significantly increases the risk of an undesired drop in the speed of rotation of the engine, for example, when the harvester hits particularly strong points in the trunk or branches during delimbing or cross-cutting. The procedure also decelerates the functions of the working machine as the continuously more slowly rotating hydraulic pump produces, on the desired pressure level, volume flows which are smaller than normally. Moreover, in a diesel engine equipped with a conventional mechanical control means, a reduction in the speed of rotation from the range of the nominal speed of rotation will also involve shifting off the range of the best efficiency of the engine. In practice, the driver cannot manually adjust the level of the speed of rotation con-tinuously as the work proceeds, but he must select a constant rotation speed level suitable for the job.
It is a primary aim of the present invention to provide a quite new method in the automatic control of the engine of a forest machine, which method enables the operation of the engine used as the primary power source for the forest machine with a better efficiency than before and thereby with a lower fuel consumption and also with significantly smaller exhaust gas emissions. The invention also relates to a forest machine implementing the method.
The basic idea of the invention is to optimize, by prediction, the control parameters of the primary power source of a forest machine, preferably a diesel engine equipped with an electronic control unit ECU, by adjusting the power source to produce a suitable and sufficient power level needed for each operation to be performed by the forest machine, without maintaining a redundant readiness for power production, wherein said operations can be performed more economically than in prior art and causing as little emissions to the environment as possible.
For understanding the basic principle of the invention, it is essential to notice that a given partial power level of the engine, for example 50 %
of the maximum power indicated for the engine, can be produced in modernry electronically controlled engines at different efficiencies by-, selecting -the control parameters of the engine in different ways. In other words, with different values of the control parameters, the fuel consumption of the engine is different, even though the same partial output of 50 % were taken from the engine in all these situations.
Reciprocally, the readiness of the engine for power production is also different with different values of the control parameters. In this context, the readiness for power production refers, first of all, to the maximum output of the engine with said values of the control parameters, but also to the way in which the engine reacts, i.e. its "aggressiveness"
when the power demand is suddenly changed. As a result, it is possi-ble to optimize the control parameters of the engine in relation to each operation to be carried out by the forest machine in such a way that the engine economically provides the sufficient power output for each operation but without maintaining an unnecessarily high readiness for power production, which thus has the disadvantage of a distinct reduc-tion in the efficiency.
In view of the fluency of working with the forest machine, the above-mentioned selection of the control parameters of the engine must be essentially made by predicting the operations of manipulating a tree trunk with the forest machine, wherein it is possible to minimize the risk of an unnecessary drop in the speed of rotation of the engine during said manipulating operations.
The invention relates particularly to such forest machines, for example harvesters, which are used for the manipulation of tree trunks on a terrain in such a way that the properties of the tree trunk subject to manipulating operations at the time are determined by means of one or more measurements of said tree trunk by the forest machine and/or by means of information entered by the driver of the forest machine into the systems of the forest machine.
One example of such measurements, known as such, is the measurement of the felling diameter of the tree trunk by the harvesting head when the harvesting head grips the upright growing tree trunk for the felling of the trunk. The diameter and the length of the trunk can be measured in ways known as such, also when the harvesting head shifts its grip of the tree trunk during delimbing and cross-cutting of the trunk.
The driver of the harvester, in turn, can, in a way known as such, enter information about the wood species of the trunk to be manipulated at the time, into the system of the harvester at the beginning of the manipulation of said trunk. On the basis of this information, the harvester can, in a way known as such, determine, for example, the estimated conicality and length of the tree trunk, and by using this so-called trunk prognosis determined for the single trunk, mark said tree trunk for cross-cutting, i.e.
make a sawing layout for cutting the trunk in an optimal way into wood products for different classes of length and diameter.
According to the invention, the properties of a single tree trunk, such as the trunk prognosis, defined at the beginning or during the manipulation DOCSTOR: 1953159\1 of said tree trunk, are used to estimate the power levels required by the manipulating operations to be carried out on said tree trunk by predic-tion, i.e. already before said manipulating operations are started. Such manipulating operations may include, for example in a harvester, the sawing for felling the tree trunk during harvesting, and the delimbing and cross-cutting of the trunk according to the sawing layout.
Consequently, the present invention is characterized in that informa-tion, such as a trunk prognosis, collected of a single tree trunk under manipulation into the system of the forest machine is used for estimat-ing by prediction in advance those power levels of the actuators of the forest machine, which will be required for the operations to be carried out for the trunk. This makes it possible that, according to the invention, it is now possible to further set the control parameters of the engine used as the primary power source for the forest machine in a signifi-cantly more specific manner so that one or more power levels required for the manipulation, of, said single tree trunk are, provided as economi cally and with as small exhaust gas emissions as possible.
According to one embodiment of the invention, for the tree trunk to be manipulated, only the highest power level required for its manipulation is estimated in advance, and the control parameters of the engine are optimized in view of this single power level only.
According to another embodiment of the invention, the power levels required for the manipulation of a tree trunk are estimated for several operations to be carried out on the trunk separately. Such operations include, for example, sawing for felling, feedings of the trunk required by delimbing at the harvesting head, and cross-cuttings of the trunk.
For these operations, several values are determined for control parameters, wherein the operation of the engine is optimized for each trunk and further for each operation. In the most advanced embodi-ment, each operation to be carried out for the tree trunk is performed by using separately optimized control parameters of the engine.
In an advantageous embodiment of the invention, the engine of the forest machine is a diesel engine, in which the fuel supply is controlled by an electronic control unit ECU instead of a mechanical control device. This makes it possible to set the control parameters for the engine in a versatile way so that the power required of the engine each time can be produced at an optimal efficiency, for example, by select-ing in each situation the most suitable control graph of those stored in the electronic control unit of the engine.
Said control graphs contain informaton relating to the scheduling and feed volumes related to the fuel supply of the engine, and the different control graphs can thus be used to affect the efficiency of the engine and further the maximum output to be achieved with said settings of the engine and the behaviour of the engine in situations of sudden changes in the load. The last mentioned adjustment, affecting the sen-sibility of the engine to react, is commonly called droop control.
In a second embodiment of the invention, also the speed of rotation of the engine is automatically selected by prediction according to the situation. In a third embodiment of the invention, the operation of the engine is optimized by actively adjusting the settings of the charger of the engine, typically a variable geometry turbocharger (variable nozzle turbocharger).
The present invention provides significant advantages to prior art.
Thanks to the invention, it is possible to significantly reduce the fuel consumption of the forest machine and thereby also the exhaust gas emissions caused by the forest machine. As the control parameters and the speed of rotation of the engine are automatically selected to be suitable for each situation, also the mechanical loading and wear caused to the engine and the other devices and parts of the forest machine are decreased, which reduces the need for maintenance of the forest machine and prolongs the lifetime of its engine and devices.
The invention also contributes to the reduction of noise levels caused by the forest machine, which is important for the working environment as well as for the driver of the machine.
In the following, the invention will be described in more detail by using, as examples, advantageous embodiments of the invention with refer-ence to the appended drawings, in which 5 Fig. 1 shows, in a principle view, the functions of a forest machine of prior art, Fig. 2 shows, in a principle view, the functions of a forest machine according to the invention, and Fig. 3 shows, in a principle chart, the optional torque graphs of an engine equipped with an electronic control unit.
Figure 1 shows, in a principle view, the functions of a forest machine of prior art. Figure 2 shows, in a corresponding manner, the functions of a forest machine according to the invention. In Figs. 1 and 2, only such functions are presented as examples which are essential for under-standing the principles of the present invention. For anyone skilled in the art, it will be obvious that in Figs. 1 and 2, the hydraulic system of the forest machine is illustrated in a very simplified manner and not in its entirety for all its parts but for those parts only which are necessary for describing the principles of the invention.
In Fig. 1, the engine 10 of the forest machine, which is typically a turbo-charged diesel engine, is arranged, according to prior art, to rotate, at a given constant speed of rotation, a hydraulic pump 11 which provides the main line 12 of the hydraulic system with either a given substan-tially constant pressure level or, under a load-sensing control, a given pressure level and volume flow. The constant pressure level is typically applied in the use of the functions of the harvesting head 21, and there may also be several different constant pressure levels to be selected for different purposes. The load-sensing control is typically used in connection with the functions of the boom 20.
The speed of rotation of the engine 10 is set to a given constant level by means of measurement 13 of the speed of rotation and a control device 14 for the engine. Conventionally, the measurement 13 of the speed of rotation and the operation of the control device 14 of the engine are connected to a mechanical governor for the injection pump of the diesel engine. The pressure level in the main line 12 is adjusted by means of a pressure measurement 15 and a control device 16 affecting the hydraulic pump 11.
From the main line 12 of the hydraulic system of the forest machine, the hydraulic power is transferred further via control valves V1-VN to different hydraulic actuators H1-HN, such as hydraulic cylinders and motors for the boom 20 and the harvesting head 21. The control valve V1-VN for a single actuator H1-HN controls, on the basis of the control signal 23 controlling the same, the volume flow and pressure of hydraulic fluid from the main line 12 to the respective actuator accord-ing to the operation performed by the actuator at the time. From the control valves V1-VN, control lines are also typically coupled to the control device 16 of the hydraulic pump 11, wherein these control lines are used to control the hydraulic system to operate either at a given constant pressure level or in a load-sensing way, depending on the control valve V1-VN and the function used at the time. Said control lines, which are not shown in Figs. 1 and 2, can be implemented either hydraulically or electrically.
The measuring and control system 22 of the forest machine is arranged, in ways known as such, to control the operations of the for-est machine according to control commands 25 from the driver. By means of measurement data 24 obtained from the harvesting head 21 and relating to the respective tree trunk subject to manipulation, the measuring and control system 22 draws up a trunk prognosis for the trunk to be manipulated, and by utilizing the trunk prognosis, marks the trunk for cross-cutting, i.e., divides it in a given manner into wood prod-ucts of different classes in length and diameter. According to the saw-ing layout obtained on the basis of the marking for cross-cutting, the measuring and control system 22 helps the driver, in ways known as such, for example by adjusting the functions of the harvesting head 21 in such a way that during the delimbing and cutting of the trunk, the trunk is automatically stopped for cross-cutting at locations complying with the sawing layout (sawing window), wherein the driver only needs to accept the cutting to be performed at the proposed location. If necessary, the driver can transfer the cutting to take place at a desired location, if the trunk has local defects, such as crooks, which have not been taken into account in the sawing layout complying with the trunk prognosis.
The measuring functions of the harvesting head 21, known as such, include the measurement of the diameter of the trunk under manipula-tion, and the measurement of the length of the trunk during the forward feeding of the trunk at the harvesting head 21.
The first trunk prognosis of the trunk to be manipulated is obtained when the harvesting head 21 of the forest machine grips the upright growing trunk at its butt end for a felling cut. At the same time, the driver preferably enters information in the measuring and control sys-tem 22 about the wood species of the trunk to be manipulated. The trunk prognosis and the marking for cross-cutting can be made more specific during the manipulation of the trunk when more detailed infor-mation is obtained e.g. on the conicality of the trunk. When making the trunk prognosis, the measuring and control system 22 can, in a way known as such, utilize information stored in its memory about trunks manipulated previously on said lot. This information can be used to specify, for example, the estimate on the conicality of the trunk and/or the knottiness of the trunk.
The sawing layout, made on the basis of the trunk prognosis, can, on one hand, be based on so-called value marking for cross-cutting, to cut as valuable pieces of the trunk as possible. On the other hand, the sawing layout can be implemented by using so-called distribution marking for cross-cutting, wherein the aim is to produce wood products belonging to different classes of length and diameter in a given propor-tion. In its simplest form, the sawing layout may be based on cutting the trunk to pieces of equal length.
The present invention is characterized in that information collected, by methods known as such, in the measuring and control system 22 about the single tree trunk to be manipulated, for example a sawing layout made on the basis of the trunk prognosis, is utilized for the estimation in advance of those power levels of the actuators H1-HN of the forest machine which will be required by the manipulating operation to be car-ried out on the trunk.
The forest machine of the invention, shown in Fig. 2, comprises a power control system 30 implementing the method according to the invention, which is arranged to control the functions of the engine in a way to be described in more detail below.
The power control system 30 is connected to a data transmission con-nection 31 with the measuring and control system 22 of the forest machine in such a way that the properties of the tree trunk under manipulation, determined at the beginning of its manipulation and/or updated during its manipulation, are available to the power control system 30. Via the data transmission connection 31, the power control system 30 also receives information about the operations to be carried out next to said trunk, for example via the sawing layout formed by the measuring and control system 22. According to the invention, this information is used by the power control system 30 to estimate the power levels required for the manipulating operations to be carried out on said tree trunk before said manipulating operations are started. On the basis of this, the power control system 30 further optimizes the functions of the engine 10 by means of the control 32 in such a way that the suitable control parameters of the engine 10, such as the speed of rotation level, the graphs controlling the fuel supply, the set-tings of the supercharger, and the droop control, have been set avail-able by prediction even before said operation is started. The timing data required for said prediction is obtained by the power control sys-tem 30 from the measuring and control system 22 via the data trans-mission connection 31.
In an advantageous embodiment of the invention, the engine 10 is a diesel engine equipped with an electronic control unit ECU, wherein the function and nature of the engine 10 can be optimized by selecting the most suitable of the control data stored in the form of graphs or charts in the electronic control unit ECU.
Figure 3 shows, in a principle view, some torque graphs M1-MN as a function of the speed of rotation of the engine. The different torque graphs M1-MN are obtained in a way known as such by means of con-trol data of the fuel supply (quantity injected, timing of injection) stored in the memory of the electronic control unit ECU. The engine can be set to function according to a given torque graph by changing the con-trol parameters of the engine electrically in a way known as such. With different settings and thereby different torque graphs, the engine gives different maximum outputs, and also the efficiency of the engine varies according to the graph selected at the time. In addition to the different torque graphs, the droop control of the engine can be changed electri-cally to affect the sensitivity of the engine to react to changes in the loading of the engine. At low droop values, the speed of rotation of the engine can drop only a little by an increase in the load, but at high droop values, the speed of rotation of the engine can, in a correspond-ing manner, temporarily drop lower when the load is suddenly increased.
If the engine 10 is a supercharged engine, preferably an engine equipped with a turbocharger, the function of the supercharger can also be controlled by prediction according to the invention. From engine technology, it is known as such to use variable geometry turbo-chargers to reduce exhaust gas emissions on the basis of exhaust gas recirculation EGR. According to the invention, the electronic control unit ECU of the engine can be fitted to control the operation of such a vari-able geometry turbocharger in such a way that the supercharging pres-sure produced by the supercharger is suitably increased in advance before the engine is loaded. An increase in the supercharging pressure also makes it possible to increase the fuel quantity supplied to the en-gine faster, wherein the engine's capacity to react to changes in the load is substantially improved.
According to the invention, for a given manipulating operation of a tree trunk, the control parameters of the engine can be used to set, for example, the torque graph used by the engine, the droop control, the settings of the supercharger, as well as the level of constant speed of rotation to a suitable level in advance, wherein said manipulating operation can be performed at an optimum efficiency but still avoiding an excessive undesired variation in the speed of rotation of the engine during said manipulating operation.
The control data for the fuel supply to the engine, stored in the form of charts or graphs in the control unit ECU, are typically entered by the engine manufacturer. These charts, which have been stored in advance in the memory of the control unit ECU and which can be 10 selected by means of the control parameters, make it possible to test the emission and noise levels of the engine at different modes and have them approved in advance by authorities.
However, the invention is not limited solely to the selection of various 15 pre-programmed charts and graphs stored in advance in the control unit ECU, but it is also possible that the control parameters are used to directly affect the fuel injection quantities, the timing of injection, or the setting of the supercharger in real time. In such an embodiment, the power control system 30, in a way, assumes some of the functions which are normally performed by the control unit ECU.
When the tree trunk under manipulation is, for example, sufficiently small, it is possible, according to the invention, to reduce the constant speed of rotation of the engine 10. The advantage of this embodiment is that when the speeds of rotation of the engine 10 and the hydraulic pump 11 are reduced, losses and wear which are caused in them, for example by friction, are also reduced. Also, the noise caused by the devices at lower speeds of rotation is at a significantly lower level.
In the simplest embodiment of the invention, the control parameters of the engine 10 and the maximum power level determined by means of them are set constant for the time of the whole harvesting of a single tree trunk. Alternatively, the control parameters of the engine can be changed separately, for example for the felling, delimbing and cross-cutting of a single tree trunk.
By means of the invention, it is also possible to determine the power levels required for moving the boom and the control parameters of the engine, optimized for their production, in a situation in which the boom is moved when the harvesting head has gripped the trunk to be manipulated. The weigt of the trunk and thereby the power levels required for moving it can be estimated, for example, on the basis of the trunk prognosis and the wood species. In cross-cutting, the change in the weight of the remaining trunk can be estimated by means of the trunk prognosis when the cross-cutting of the trunk proceeds according to the sawing layout.
In its simplest form, the automatic selection of the control parameters of the engine of the forest machine according to the invention can be made, for example, solely on the basis of the felling diameter of the trunk and/or the wood species of the trunk. In more advanced optimi-zation according to the invention, the selection of the power levels is made on the basis of the trunk prognosis and/or the sawing or manipulating layout of the trunk, derived from the trunk prognosis.
In the control of the engine of the forest machine, preferably the delays in the different control methods are taken in account. The selection of the different torque graphs M1-MN or droop values by electrically affecting the electronic control unit ECU is fast and has a substantially immediate effect on the function of the engine. Compared with the above-mentioned variables, the effect of adjusting the speed of rotation of the diesel engine is distinctly slower, the delay in major changes in the speed of rotation being even in the order of a few seconds. In the change of the settings of the supercharger and the supercharging pressure, the delays typically fall in the middle ground between the above-mentioned delays.
Naturally, it is obvious that if the power control system is utilized when the forest machine is transferred from one harvesting location to another, it is possible to select control parameters for the engine which are economically suitable for the transport. The selection of the power level and thereby the control parameters of the engine can also be made by the driver of the forest machine who may, in certain situations, set edge conditions for the automatic control of the engine by the power control system 30, or the driver may also, if necessary, manually by-pass the power control system 30, forcing the forest machine to a specific power control mode.
In one embodiment of the invention, the power control system 30 is arranged to give the driver of the forest machine feedback of the fuel consumption of the forest machine, wherein the driver is motivated to work in such a way that the fuel consumption remains as low as possi-ble.
By the present invention, it is possible to significantly reduce the fuel consumption of the forest machine per produced cubic metre of timber.
This reduces the operating costs of the machine, but furthermore, par-ticularly the emissions from the forest machine to the environment are also distinctly reduced. This is important, because in view of the whole life cycle of the forest machine, about 80 % of the environmental load caused by the forest machine is due to emissions from the diesel engine. Furthermore, the invention also reduces the loading and wear-ing of the engine and devices of the forest machine, as well as reduces the noise level caused by the forest machine.
By combining the modes and system structures presented in connec-tion with the above embodiments of the invention, it is possible to pro-vide various embodiments of the invention which comply with the spirit of the invention. Therefore, the above-presented examples must not be interpreted as restrictive to the invention, but the embodiments of the invention can be freely varied within the scope of the inventive features presented in the claims hereinbelow.
For example, it is obvious that in the estimation of the power levels required by the operations to be carried out on the tree trunk, these power levels do not need to be determined, for example, in kilowatts or corresponding absolute values, but it is also possible to use other parameters which describe the power demand and the loading of the engine caused by the operation.
The power source must also be capable of overcoming situations in which, for example, several hydraulic functions of the boom and the harvesting head are applied simultaneously during the manipulation of a heavy trunk. Consequently, the selection falls on a diesel engine whose power and torque properties provide an optimum compromise of the needs occurring in practice.
However, it is the maximum needs of the functions of the forest machine which primarily determine the size, nature and operating mode, to be kept substantially constant, for the engine to be selected for the forest machine; consequently, the arrangements of prior art are not operating in the range of the best efficiency when said engine is loaded with a partial load only. In practice, maximum output of the engine and the hydraulic system is required only occasionally, and during most of the operating time, a partial power substantially lower than the maximum capacity is applied. As a result, the efficiency and the specific fuel consumption of the engine are not optimal during typi-cal use of the forest machine according to arrangements of prior art.
The reason for the poor efficiency with partial loads can be understood in the following way. According to prior art, the engine is only aimed at keeping its speed of rotation at a constant level, corresponding to the respective valid need for the speed of rotation, wherein the power out-put of the engine, in practice, also follows the engine output required by the hydraulic pump at each time. However, since the engine is not subjected to any other control parameters representing more closely the on-going working situation or particularly the forthcoming situation, the readiness for power production is always at a maximum level in the arrangements of prior art. In other words, the engine is ready to pro-duce more power up to its maximum capacity only by increasing the throttle, if this is required by the power intake of the hydraulic pump from the shaft of the engine. In situations of partial loading, this readi-ness for power production which is unnecessarily high and redundant to be maintained, reduces the efficiency of the engine, because the 5 settings effective on the method of fuel supply into the engine are con-tinuously "maintained" optimal for the maximum output only. With par-tial outputs, these settings prevent the operation of the engine at an optimal efficiency, thereby increasing the fuel consumption of the engine, which is further manifested, for example, as an increase in the quantity of harmful exhaust gas emissions.
Furthermore, a mode of the forest machine is known from prior art, in which the driver of the harvester when in light work, for example work-ing in a stand marked for cutting and containing only relatively small trunks, manually adjusts the level of the constant speed of rotation used in the diesel engine to a lower constant level than normally in a situation when the maximum output of the engine is not likely to be used. This procedure reduces the engine's readiness for power pro duction and thereby reduces the total fuel consumption of the working machine, but it also significantly increases the risk of an undesired drop in the speed of rotation of the engine, for example, when the harvester hits particularly strong points in the trunk or branches during delimbing or cross-cutting. The procedure also decelerates the functions of the working machine as the continuously more slowly rotating hydraulic pump produces, on the desired pressure level, volume flows which are smaller than normally. Moreover, in a diesel engine equipped with a conventional mechanical control means, a reduction in the speed of rotation from the range of the nominal speed of rotation will also involve shifting off the range of the best efficiency of the engine. In practice, the driver cannot manually adjust the level of the speed of rotation con-tinuously as the work proceeds, but he must select a constant rotation speed level suitable for the job.
It is a primary aim of the present invention to provide a quite new method in the automatic control of the engine of a forest machine, which method enables the operation of the engine used as the primary power source for the forest machine with a better efficiency than before and thereby with a lower fuel consumption and also with significantly smaller exhaust gas emissions. The invention also relates to a forest machine implementing the method.
The basic idea of the invention is to optimize, by prediction, the control parameters of the primary power source of a forest machine, preferably a diesel engine equipped with an electronic control unit ECU, by adjusting the power source to produce a suitable and sufficient power level needed for each operation to be performed by the forest machine, without maintaining a redundant readiness for power production, wherein said operations can be performed more economically than in prior art and causing as little emissions to the environment as possible.
For understanding the basic principle of the invention, it is essential to notice that a given partial power level of the engine, for example 50 %
of the maximum power indicated for the engine, can be produced in modernry electronically controlled engines at different efficiencies by-, selecting -the control parameters of the engine in different ways. In other words, with different values of the control parameters, the fuel consumption of the engine is different, even though the same partial output of 50 % were taken from the engine in all these situations.
Reciprocally, the readiness of the engine for power production is also different with different values of the control parameters. In this context, the readiness for power production refers, first of all, to the maximum output of the engine with said values of the control parameters, but also to the way in which the engine reacts, i.e. its "aggressiveness"
when the power demand is suddenly changed. As a result, it is possi-ble to optimize the control parameters of the engine in relation to each operation to be carried out by the forest machine in such a way that the engine economically provides the sufficient power output for each operation but without maintaining an unnecessarily high readiness for power production, which thus has the disadvantage of a distinct reduc-tion in the efficiency.
In view of the fluency of working with the forest machine, the above-mentioned selection of the control parameters of the engine must be essentially made by predicting the operations of manipulating a tree trunk with the forest machine, wherein it is possible to minimize the risk of an unnecessary drop in the speed of rotation of the engine during said manipulating operations.
The invention relates particularly to such forest machines, for example harvesters, which are used for the manipulation of tree trunks on a terrain in such a way that the properties of the tree trunk subject to manipulating operations at the time are determined by means of one or more measurements of said tree trunk by the forest machine and/or by means of information entered by the driver of the forest machine into the systems of the forest machine.
One example of such measurements, known as such, is the measurement of the felling diameter of the tree trunk by the harvesting head when the harvesting head grips the upright growing tree trunk for the felling of the trunk. The diameter and the length of the trunk can be measured in ways known as such, also when the harvesting head shifts its grip of the tree trunk during delimbing and cross-cutting of the trunk.
The driver of the harvester, in turn, can, in a way known as such, enter information about the wood species of the trunk to be manipulated at the time, into the system of the harvester at the beginning of the manipulation of said trunk. On the basis of this information, the harvester can, in a way known as such, determine, for example, the estimated conicality and length of the tree trunk, and by using this so-called trunk prognosis determined for the single trunk, mark said tree trunk for cross-cutting, i.e.
make a sawing layout for cutting the trunk in an optimal way into wood products for different classes of length and diameter.
According to the invention, the properties of a single tree trunk, such as the trunk prognosis, defined at the beginning or during the manipulation DOCSTOR: 1953159\1 of said tree trunk, are used to estimate the power levels required by the manipulating operations to be carried out on said tree trunk by predic-tion, i.e. already before said manipulating operations are started. Such manipulating operations may include, for example in a harvester, the sawing for felling the tree trunk during harvesting, and the delimbing and cross-cutting of the trunk according to the sawing layout.
Consequently, the present invention is characterized in that informa-tion, such as a trunk prognosis, collected of a single tree trunk under manipulation into the system of the forest machine is used for estimat-ing by prediction in advance those power levels of the actuators of the forest machine, which will be required for the operations to be carried out for the trunk. This makes it possible that, according to the invention, it is now possible to further set the control parameters of the engine used as the primary power source for the forest machine in a signifi-cantly more specific manner so that one or more power levels required for the manipulation, of, said single tree trunk are, provided as economi cally and with as small exhaust gas emissions as possible.
According to one embodiment of the invention, for the tree trunk to be manipulated, only the highest power level required for its manipulation is estimated in advance, and the control parameters of the engine are optimized in view of this single power level only.
According to another embodiment of the invention, the power levels required for the manipulation of a tree trunk are estimated for several operations to be carried out on the trunk separately. Such operations include, for example, sawing for felling, feedings of the trunk required by delimbing at the harvesting head, and cross-cuttings of the trunk.
For these operations, several values are determined for control parameters, wherein the operation of the engine is optimized for each trunk and further for each operation. In the most advanced embodi-ment, each operation to be carried out for the tree trunk is performed by using separately optimized control parameters of the engine.
In an advantageous embodiment of the invention, the engine of the forest machine is a diesel engine, in which the fuel supply is controlled by an electronic control unit ECU instead of a mechanical control device. This makes it possible to set the control parameters for the engine in a versatile way so that the power required of the engine each time can be produced at an optimal efficiency, for example, by select-ing in each situation the most suitable control graph of those stored in the electronic control unit of the engine.
Said control graphs contain informaton relating to the scheduling and feed volumes related to the fuel supply of the engine, and the different control graphs can thus be used to affect the efficiency of the engine and further the maximum output to be achieved with said settings of the engine and the behaviour of the engine in situations of sudden changes in the load. The last mentioned adjustment, affecting the sen-sibility of the engine to react, is commonly called droop control.
In a second embodiment of the invention, also the speed of rotation of the engine is automatically selected by prediction according to the situation. In a third embodiment of the invention, the operation of the engine is optimized by actively adjusting the settings of the charger of the engine, typically a variable geometry turbocharger (variable nozzle turbocharger).
The present invention provides significant advantages to prior art.
Thanks to the invention, it is possible to significantly reduce the fuel consumption of the forest machine and thereby also the exhaust gas emissions caused by the forest machine. As the control parameters and the speed of rotation of the engine are automatically selected to be suitable for each situation, also the mechanical loading and wear caused to the engine and the other devices and parts of the forest machine are decreased, which reduces the need for maintenance of the forest machine and prolongs the lifetime of its engine and devices.
The invention also contributes to the reduction of noise levels caused by the forest machine, which is important for the working environment as well as for the driver of the machine.
In the following, the invention will be described in more detail by using, as examples, advantageous embodiments of the invention with refer-ence to the appended drawings, in which 5 Fig. 1 shows, in a principle view, the functions of a forest machine of prior art, Fig. 2 shows, in a principle view, the functions of a forest machine according to the invention, and Fig. 3 shows, in a principle chart, the optional torque graphs of an engine equipped with an electronic control unit.
Figure 1 shows, in a principle view, the functions of a forest machine of prior art. Figure 2 shows, in a corresponding manner, the functions of a forest machine according to the invention. In Figs. 1 and 2, only such functions are presented as examples which are essential for under-standing the principles of the present invention. For anyone skilled in the art, it will be obvious that in Figs. 1 and 2, the hydraulic system of the forest machine is illustrated in a very simplified manner and not in its entirety for all its parts but for those parts only which are necessary for describing the principles of the invention.
In Fig. 1, the engine 10 of the forest machine, which is typically a turbo-charged diesel engine, is arranged, according to prior art, to rotate, at a given constant speed of rotation, a hydraulic pump 11 which provides the main line 12 of the hydraulic system with either a given substan-tially constant pressure level or, under a load-sensing control, a given pressure level and volume flow. The constant pressure level is typically applied in the use of the functions of the harvesting head 21, and there may also be several different constant pressure levels to be selected for different purposes. The load-sensing control is typically used in connection with the functions of the boom 20.
The speed of rotation of the engine 10 is set to a given constant level by means of measurement 13 of the speed of rotation and a control device 14 for the engine. Conventionally, the measurement 13 of the speed of rotation and the operation of the control device 14 of the engine are connected to a mechanical governor for the injection pump of the diesel engine. The pressure level in the main line 12 is adjusted by means of a pressure measurement 15 and a control device 16 affecting the hydraulic pump 11.
From the main line 12 of the hydraulic system of the forest machine, the hydraulic power is transferred further via control valves V1-VN to different hydraulic actuators H1-HN, such as hydraulic cylinders and motors for the boom 20 and the harvesting head 21. The control valve V1-VN for a single actuator H1-HN controls, on the basis of the control signal 23 controlling the same, the volume flow and pressure of hydraulic fluid from the main line 12 to the respective actuator accord-ing to the operation performed by the actuator at the time. From the control valves V1-VN, control lines are also typically coupled to the control device 16 of the hydraulic pump 11, wherein these control lines are used to control the hydraulic system to operate either at a given constant pressure level or in a load-sensing way, depending on the control valve V1-VN and the function used at the time. Said control lines, which are not shown in Figs. 1 and 2, can be implemented either hydraulically or electrically.
The measuring and control system 22 of the forest machine is arranged, in ways known as such, to control the operations of the for-est machine according to control commands 25 from the driver. By means of measurement data 24 obtained from the harvesting head 21 and relating to the respective tree trunk subject to manipulation, the measuring and control system 22 draws up a trunk prognosis for the trunk to be manipulated, and by utilizing the trunk prognosis, marks the trunk for cross-cutting, i.e., divides it in a given manner into wood prod-ucts of different classes in length and diameter. According to the saw-ing layout obtained on the basis of the marking for cross-cutting, the measuring and control system 22 helps the driver, in ways known as such, for example by adjusting the functions of the harvesting head 21 in such a way that during the delimbing and cutting of the trunk, the trunk is automatically stopped for cross-cutting at locations complying with the sawing layout (sawing window), wherein the driver only needs to accept the cutting to be performed at the proposed location. If necessary, the driver can transfer the cutting to take place at a desired location, if the trunk has local defects, such as crooks, which have not been taken into account in the sawing layout complying with the trunk prognosis.
The measuring functions of the harvesting head 21, known as such, include the measurement of the diameter of the trunk under manipula-tion, and the measurement of the length of the trunk during the forward feeding of the trunk at the harvesting head 21.
The first trunk prognosis of the trunk to be manipulated is obtained when the harvesting head 21 of the forest machine grips the upright growing trunk at its butt end for a felling cut. At the same time, the driver preferably enters information in the measuring and control sys-tem 22 about the wood species of the trunk to be manipulated. The trunk prognosis and the marking for cross-cutting can be made more specific during the manipulation of the trunk when more detailed infor-mation is obtained e.g. on the conicality of the trunk. When making the trunk prognosis, the measuring and control system 22 can, in a way known as such, utilize information stored in its memory about trunks manipulated previously on said lot. This information can be used to specify, for example, the estimate on the conicality of the trunk and/or the knottiness of the trunk.
The sawing layout, made on the basis of the trunk prognosis, can, on one hand, be based on so-called value marking for cross-cutting, to cut as valuable pieces of the trunk as possible. On the other hand, the sawing layout can be implemented by using so-called distribution marking for cross-cutting, wherein the aim is to produce wood products belonging to different classes of length and diameter in a given propor-tion. In its simplest form, the sawing layout may be based on cutting the trunk to pieces of equal length.
The present invention is characterized in that information collected, by methods known as such, in the measuring and control system 22 about the single tree trunk to be manipulated, for example a sawing layout made on the basis of the trunk prognosis, is utilized for the estimation in advance of those power levels of the actuators H1-HN of the forest machine which will be required by the manipulating operation to be car-ried out on the trunk.
The forest machine of the invention, shown in Fig. 2, comprises a power control system 30 implementing the method according to the invention, which is arranged to control the functions of the engine in a way to be described in more detail below.
The power control system 30 is connected to a data transmission con-nection 31 with the measuring and control system 22 of the forest machine in such a way that the properties of the tree trunk under manipulation, determined at the beginning of its manipulation and/or updated during its manipulation, are available to the power control system 30. Via the data transmission connection 31, the power control system 30 also receives information about the operations to be carried out next to said trunk, for example via the sawing layout formed by the measuring and control system 22. According to the invention, this information is used by the power control system 30 to estimate the power levels required for the manipulating operations to be carried out on said tree trunk before said manipulating operations are started. On the basis of this, the power control system 30 further optimizes the functions of the engine 10 by means of the control 32 in such a way that the suitable control parameters of the engine 10, such as the speed of rotation level, the graphs controlling the fuel supply, the set-tings of the supercharger, and the droop control, have been set avail-able by prediction even before said operation is started. The timing data required for said prediction is obtained by the power control sys-tem 30 from the measuring and control system 22 via the data trans-mission connection 31.
In an advantageous embodiment of the invention, the engine 10 is a diesel engine equipped with an electronic control unit ECU, wherein the function and nature of the engine 10 can be optimized by selecting the most suitable of the control data stored in the form of graphs or charts in the electronic control unit ECU.
Figure 3 shows, in a principle view, some torque graphs M1-MN as a function of the speed of rotation of the engine. The different torque graphs M1-MN are obtained in a way known as such by means of con-trol data of the fuel supply (quantity injected, timing of injection) stored in the memory of the electronic control unit ECU. The engine can be set to function according to a given torque graph by changing the con-trol parameters of the engine electrically in a way known as such. With different settings and thereby different torque graphs, the engine gives different maximum outputs, and also the efficiency of the engine varies according to the graph selected at the time. In addition to the different torque graphs, the droop control of the engine can be changed electri-cally to affect the sensitivity of the engine to react to changes in the loading of the engine. At low droop values, the speed of rotation of the engine can drop only a little by an increase in the load, but at high droop values, the speed of rotation of the engine can, in a correspond-ing manner, temporarily drop lower when the load is suddenly increased.
If the engine 10 is a supercharged engine, preferably an engine equipped with a turbocharger, the function of the supercharger can also be controlled by prediction according to the invention. From engine technology, it is known as such to use variable geometry turbo-chargers to reduce exhaust gas emissions on the basis of exhaust gas recirculation EGR. According to the invention, the electronic control unit ECU of the engine can be fitted to control the operation of such a vari-able geometry turbocharger in such a way that the supercharging pres-sure produced by the supercharger is suitably increased in advance before the engine is loaded. An increase in the supercharging pressure also makes it possible to increase the fuel quantity supplied to the en-gine faster, wherein the engine's capacity to react to changes in the load is substantially improved.
According to the invention, for a given manipulating operation of a tree trunk, the control parameters of the engine can be used to set, for example, the torque graph used by the engine, the droop control, the settings of the supercharger, as well as the level of constant speed of rotation to a suitable level in advance, wherein said manipulating operation can be performed at an optimum efficiency but still avoiding an excessive undesired variation in the speed of rotation of the engine during said manipulating operation.
The control data for the fuel supply to the engine, stored in the form of charts or graphs in the control unit ECU, are typically entered by the engine manufacturer. These charts, which have been stored in advance in the memory of the control unit ECU and which can be 10 selected by means of the control parameters, make it possible to test the emission and noise levels of the engine at different modes and have them approved in advance by authorities.
However, the invention is not limited solely to the selection of various 15 pre-programmed charts and graphs stored in advance in the control unit ECU, but it is also possible that the control parameters are used to directly affect the fuel injection quantities, the timing of injection, or the setting of the supercharger in real time. In such an embodiment, the power control system 30, in a way, assumes some of the functions which are normally performed by the control unit ECU.
When the tree trunk under manipulation is, for example, sufficiently small, it is possible, according to the invention, to reduce the constant speed of rotation of the engine 10. The advantage of this embodiment is that when the speeds of rotation of the engine 10 and the hydraulic pump 11 are reduced, losses and wear which are caused in them, for example by friction, are also reduced. Also, the noise caused by the devices at lower speeds of rotation is at a significantly lower level.
In the simplest embodiment of the invention, the control parameters of the engine 10 and the maximum power level determined by means of them are set constant for the time of the whole harvesting of a single tree trunk. Alternatively, the control parameters of the engine can be changed separately, for example for the felling, delimbing and cross-cutting of a single tree trunk.
By means of the invention, it is also possible to determine the power levels required for moving the boom and the control parameters of the engine, optimized for their production, in a situation in which the boom is moved when the harvesting head has gripped the trunk to be manipulated. The weigt of the trunk and thereby the power levels required for moving it can be estimated, for example, on the basis of the trunk prognosis and the wood species. In cross-cutting, the change in the weight of the remaining trunk can be estimated by means of the trunk prognosis when the cross-cutting of the trunk proceeds according to the sawing layout.
In its simplest form, the automatic selection of the control parameters of the engine of the forest machine according to the invention can be made, for example, solely on the basis of the felling diameter of the trunk and/or the wood species of the trunk. In more advanced optimi-zation according to the invention, the selection of the power levels is made on the basis of the trunk prognosis and/or the sawing or manipulating layout of the trunk, derived from the trunk prognosis.
In the control of the engine of the forest machine, preferably the delays in the different control methods are taken in account. The selection of the different torque graphs M1-MN or droop values by electrically affecting the electronic control unit ECU is fast and has a substantially immediate effect on the function of the engine. Compared with the above-mentioned variables, the effect of adjusting the speed of rotation of the diesel engine is distinctly slower, the delay in major changes in the speed of rotation being even in the order of a few seconds. In the change of the settings of the supercharger and the supercharging pressure, the delays typically fall in the middle ground between the above-mentioned delays.
Naturally, it is obvious that if the power control system is utilized when the forest machine is transferred from one harvesting location to another, it is possible to select control parameters for the engine which are economically suitable for the transport. The selection of the power level and thereby the control parameters of the engine can also be made by the driver of the forest machine who may, in certain situations, set edge conditions for the automatic control of the engine by the power control system 30, or the driver may also, if necessary, manually by-pass the power control system 30, forcing the forest machine to a specific power control mode.
In one embodiment of the invention, the power control system 30 is arranged to give the driver of the forest machine feedback of the fuel consumption of the forest machine, wherein the driver is motivated to work in such a way that the fuel consumption remains as low as possi-ble.
By the present invention, it is possible to significantly reduce the fuel consumption of the forest machine per produced cubic metre of timber.
This reduces the operating costs of the machine, but furthermore, par-ticularly the emissions from the forest machine to the environment are also distinctly reduced. This is important, because in view of the whole life cycle of the forest machine, about 80 % of the environmental load caused by the forest machine is due to emissions from the diesel engine. Furthermore, the invention also reduces the loading and wear-ing of the engine and devices of the forest machine, as well as reduces the noise level caused by the forest machine.
By combining the modes and system structures presented in connec-tion with the above embodiments of the invention, it is possible to pro-vide various embodiments of the invention which comply with the spirit of the invention. Therefore, the above-presented examples must not be interpreted as restrictive to the invention, but the embodiments of the invention can be freely varied within the scope of the inventive features presented in the claims hereinbelow.
For example, it is obvious that in the estimation of the power levels required by the operations to be carried out on the tree trunk, these power levels do not need to be determined, for example, in kilowatts or corresponding absolute values, but it is also possible to use other parameters which describe the power demand and the loading of the engine caused by the operation.
Claims (24)
1. A method in the control of an engine used as the primary power source for a forest machine, the method comprising the steps of:
performing manipulation operations of tree trunks on a terrain using a forest machine by driving actuators of the forest machine;
determining, at the beginning of or during the manipulation operations of a single tree trunk, properties of the tree trunk subject to the manipulation operations by means of one or more measurements of said tree trunk, said one or more measurements being carried out by the forest machine;
estimating automatically in advance, on the basis of the determined properties of the tree trunk, before performing one or more further manipulation operations of the tree trunk, one or more power levels of the actuators required by said one or more further manipulating operations of said tree trunk; and on the basis of the estimation:
affecting control parameters of the engine used as the primary power source, the control parameters being used for adjusting the engine to produce a given power level, by automatically optimizing the efficiency of the engine and by providing a power level sufficient for said one or more power levels required for the further manipulation operations of the tree trunk.
performing manipulation operations of tree trunks on a terrain using a forest machine by driving actuators of the forest machine;
determining, at the beginning of or during the manipulation operations of a single tree trunk, properties of the tree trunk subject to the manipulation operations by means of one or more measurements of said tree trunk, said one or more measurements being carried out by the forest machine;
estimating automatically in advance, on the basis of the determined properties of the tree trunk, before performing one or more further manipulation operations of the tree trunk, one or more power levels of the actuators required by said one or more further manipulating operations of said tree trunk; and on the basis of the estimation:
affecting control parameters of the engine used as the primary power source, the control parameters being used for adjusting the engine to produce a given power level, by automatically optimizing the efficiency of the engine and by providing a power level sufficient for said one or more power levels required for the further manipulation operations of the tree trunk.
2. The method according to claim 1, wherein the method further comprises:
determining the properties of the tree trunk also by means of information related to the tree trunk and entered into the forest machine by the driver of the forest machine.
determining the properties of the tree trunk also by means of information related to the tree trunk and entered into the forest machine by the driver of the forest machine.
3. The method according to claim 1 or 2, wherein the method further comprises:
optimizing harmful emissions or the noise level of the engine of the forest machine.
optimizing harmful emissions or the noise level of the engine of the forest machine.
4. The method according to any one of the preceding claims 1 to 3, wherein the method further comprises:
optimizing the speed of rotation of the engine.
optimizing the speed of rotation of the engine.
5. The method according to any one of the preceding claims 1 to 4, wherein the engine is equipped with an electronic control unit, and wherein the method further comprises:
oprimizing the function of the engine by using the control parameters to make a selection between settings pre-programmed in the electronic control unit of the engine and affecting the fuel supply.
oprimizing the function of the engine by using the control parameters to make a selection between settings pre-programmed in the electronic control unit of the engine and affecting the fuel supply.
6. The method according to any one of the preceding claims 1 to 4, wherein the engine is equipped with an electronic control unit, and wherein the method further comprises:
optimizing the function of the engine by using the control parameters to make a selection between settings pre-programmed in the electronic control unit of the engine and affecting the fuel supply, namely torque graphs, such that the engine gives different maximum outputs.
optimizing the function of the engine by using the control parameters to make a selection between settings pre-programmed in the electronic control unit of the engine and affecting the fuel supply, namely torque graphs, such that the engine gives different maximum outputs.
7. The method according to any one of the preceding claims 1 to 4 wherein the engine is equipped with an electronic control unit, and wherein the method further comprises:
optimizing the function of the engine by making a selection between various droop settings of the engine.
optimizing the function of the engine by making a selection between various droop settings of the engine.
8. The method according to any one of the preceding claims 1 to 7, wherein the engine is equipped with a supercharger, and wherein the method further comprises:
optimizing the function of the engine by affecting settings of the supercharger of the engine.
optimizing the function of the engine by affecting settings of the supercharger of the engine.
9. The method according to any one of the preceding claims 1 to 8, wherein the method further comprises:
determining said one or more power levels required for the further manipulation of the tree trunk on the basis of a trunk prognosis for the tree trunk.
determining said one or more power levels required for the further manipulation of the tree trunk on the basis of a trunk prognosis for the tree trunk.
10. The method according to any one of the preceding claims 1 to 9, wherein the method further comprises:
determining said one or more power levels required for the further manipulation of the tree trunk on the basis of a sawing layout formed for the tree trunk.
determining said one or more power levels required for the further manipulation of the tree trunk on the basis of a sawing layout formed for the tree trunk.
11. The method according to any one of the preceding claims 1 to 10, wherein the method further comprises:
determining said one or more power levels required for the further manipulation of the tree trunk on the basis of the diameter of the tree trunk.
determining said one or more power levels required for the further manipulation of the tree trunk on the basis of the diameter of the tree trunk.
12. The method according to any one of the preceding claims 1 to 11, wherein the method further comprises:
determining said one or more power levels required for the further manipulation of the tree trunk on the basis of the wood species of the tree trunk.
determining said one or more power levels required for the further manipulation of the tree trunk on the basis of the wood species of the tree trunk.
13. A forest machine for performing manipulation of tree trunks on a terrain, the forest machine comprising:
an engine used as the primary power source;
actuators for performing the manipulation of tree trunks;
a measuring and control system for determining properties of a tree trunk subject to manipulating operations of the forest machine at the time, by means of one or more measurements carried out by the measuring and control system, and for storing or updating the determined properties of the tree trunk at the beginning of the manipulation of the tree trunk or during the manipulation of the tree trunk;
a power control system;
wherein the power control system is configured to estimate automatically in advance, on the basis of the determined properties of a single trunk and before performing one or more further manipulation operations of the tree trunk, one or more power levels of the actuators required by said one or more further manipulating operations of the tree trunk; and wherein the power control system is further configured to optimize the efficiency of the engine automatically on the basis of estimation, by affecting control parameters of the engine, the control parameters being used for adjusting the engine to produce a given power level, and by providing a power level sufficent for said one or more power levels required for the further manipulation operations of the tree trunk.
an engine used as the primary power source;
actuators for performing the manipulation of tree trunks;
a measuring and control system for determining properties of a tree trunk subject to manipulating operations of the forest machine at the time, by means of one or more measurements carried out by the measuring and control system, and for storing or updating the determined properties of the tree trunk at the beginning of the manipulation of the tree trunk or during the manipulation of the tree trunk;
a power control system;
wherein the power control system is configured to estimate automatically in advance, on the basis of the determined properties of a single trunk and before performing one or more further manipulation operations of the tree trunk, one or more power levels of the actuators required by said one or more further manipulating operations of the tree trunk; and wherein the power control system is further configured to optimize the efficiency of the engine automatically on the basis of estimation, by affecting control parameters of the engine, the control parameters being used for adjusting the engine to produce a given power level, and by providing a power level sufficent for said one or more power levels required for the further manipulation operations of the tree trunk.
14. The forest machine according to claim 13, wherein the measuring and control system is further configured to determine properties of the tree trunk by means of information related to the tree trunk and entered in the measuring and control system by the driver of the forest machine.
15. The forest machine according to claim 13 or 14, wherein said power control system is further configured to optimize harmful emissions or the noise level of the forest machine.
16. The forest machine according to any one of the preceding claims 13 to 15, wherein said power control system is further configured to optimize the speed of rotation of the engine.
17. The forest machine according to any one of the preceding claims 13 to 16, wherein the engine is equipped with an electronic control unit;
and wherein the power control system is configured to optimize the function of the engine by using the control parameters to make a selection between settings pre-programmed in the electronic control unit of the engine and affecting the fuel supply.
and wherein the power control system is configured to optimize the function of the engine by using the control parameters to make a selection between settings pre-programmed in the electronic control unit of the engine and affecting the fuel supply.
18. The method according to any one of the preceding claims 13 to 16, wherein the engine is equipped with an electronic control unit;
and wherein the electronic control unit is configured to optimize the function of the engine by using the control parameters to make a selection between settings pre-programmed in the electronic control unit of the engine and affecting the fuel supply, namely torque graphs, such that the engine gives different maximum outputs.
and wherein the electronic control unit is configured to optimize the function of the engine by using the control parameters to make a selection between settings pre-programmed in the electronic control unit of the engine and affecting the fuel supply, namely torque graphs, such that the engine gives different maximum outputs.
19. The forest machine according to any one of the preceding claims 13 to 16, wherein the engine is equipped with an electronic control unit;
and wherein the power control system is configured to optimize the function of the engine by using the control parameters to make a selection between different droop settings of the engine.
and wherein the power control system is configured to optimize the function of the engine by using the control parameters to make a selection between different droop settings of the engine.
20. The forest machine according to any one of the preceding claims 13 to 19, wherein the engine is equipped with a supercharger, and wherein said power control system is configured to optimize the function of the engine by affecting settings of the supercharger of the engine.
21. The forest machine according to any one of the preceding claims 13 to 20, wherein the power control system is configured to determine said one or more power levels required for the further manipulation of the tree trunk on the basis of a trunk prognosis for the tree trunk.
22. The forest machine according to any one of the preceding claims 13 to 21, wherein the power control system is configured to determine said one or more power levels required for the furthe rmanipulation of the tree trunk on the basis of a sawing layout formed for the tree trunk.
23. The forest machine according to any one of the preceding claims 13 to 22, wherein the power control system is configured to determine said one or more power levels required for the further manipulation of the tree trunk on the basis of the diameter of the tree trunk.
24. The forest machine according to any one of the preceding claims 13 to 23, wherein the power control system is configured to determine said one or more power levels required for the further manipulation of the tree trunk on the basis of the wood species of the tree trunk.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FI20020957 | 2002-05-21 | ||
| FI20020957A FI111183B (en) | 2002-05-21 | 2002-05-21 | Procedure for control of forest machine engine and forest machine |
| PCT/FI2003/000387 WO2003096794A1 (en) | 2002-05-21 | 2003-05-20 | A method in controlling an engine of a forest machine and a forest machine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2486278A1 CA2486278A1 (en) | 2003-11-27 |
| CA2486278C true CA2486278C (en) | 2012-03-13 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2486278A Expired - Fee Related CA2486278C (en) | 2002-05-21 | 2003-05-20 | A method in controlling an engine of a forest machine and a forest machine |
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| AU (1) | AU2003227795A1 (en) |
| CA (1) | CA2486278C (en) |
| DE (1) | DE10392696T5 (en) |
| FI (1) | FI111183B (en) |
| SE (1) | SE527297C2 (en) |
| WO (1) | WO2003096794A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| FI119394B (en) * | 2005-12-02 | 2008-10-31 | Ponsse Oyj | Method for controlling the power of a forestry machine |
| FI122061B (en) * | 2007-05-28 | 2011-08-15 | Ponsse Oyj | Arrangement in connection with forestry machine power source |
| RU2522525C2 (en) * | 2012-11-01 | 2014-07-20 | Лев Николаевич Шобанов | Method for machine guidance on object |
| AU2013408441B2 (en) * | 2013-12-20 | 2018-05-10 | Komatsu Forest Ab | Indicating of unsharp teeth at a disc saw by measuring of speed of rotation |
| DE102016003752B4 (en) * | 2016-03-26 | 2022-06-09 | Audi Ag | Method for operating a drive device of a motor vehicle and corresponding drive device |
| SE540505C2 (en) * | 2016-05-17 | 2018-09-25 | Log Max Ab | A tree harvesting machine, a tree harvesting monitoring system, a tree harvesting head, a method for controlling operation of a tree harvesting head and a method for monitoring operation of a tree harvesting machine |
| EP3424296B1 (en) * | 2017-07-04 | 2023-11-29 | Andreas Stihl AG & Co. KG | Method for determining an item of information for adjusting an adjustable component of a combustion motor drive system of a gardening and/or forestry device, gardening and/or forestry device system and garden and/or forestry device |
| FI20185718A1 (en) | 2018-08-30 | 2020-03-01 | Ponsse Oyj | Method for controlling a power transmission device, system and forest machine |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE388752B (en) * | 1975-03-06 | 1976-10-18 | Volvo Bm | DEVICE FOR CUTTING TREES OF TREES |
| US5394342A (en) * | 1993-02-26 | 1995-02-28 | Macmillan Bloedel Limited | Log scanning |
| SE9703236L (en) * | 1997-09-09 | 1999-03-10 | Rolf Modd | Device for operation of a processing unit |
| FI20002683A0 (en) * | 2000-12-07 | 2000-12-07 | Taehkae Ab Oy | Plant and procedure for handling logs |
-
2002
- 2002-05-21 FI FI20020957A patent/FI111183B/en not_active IP Right Cessation
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2003
- 2003-05-20 DE DE10392696T patent/DE10392696T5/en not_active Withdrawn
- 2003-05-20 WO PCT/FI2003/000387 patent/WO2003096794A1/en not_active Application Discontinuation
- 2003-05-20 AU AU2003227795A patent/AU2003227795A1/en not_active Abandoned
- 2003-05-20 CA CA2486278A patent/CA2486278C/en not_active Expired - Fee Related
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2004
- 2004-11-05 SE SE0402685A patent/SE527297C2/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| FI20020957A0 (en) | 2002-05-21 |
| DE10392696T5 (en) | 2005-05-25 |
| SE0402685L (en) | 2004-11-05 |
| FI111183B (en) | 2003-06-13 |
| SE527297C2 (en) | 2006-02-07 |
| SE0402685D0 (en) | 2004-11-05 |
| WO2003096794A1 (en) | 2003-11-27 |
| CA2486278A1 (en) | 2003-11-27 |
| AU2003227795A1 (en) | 2003-12-02 |
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| Date | Code | Title | Description |
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| EEER | Examination request | ||
| MKLA | Lapsed |
Effective date: 20170523 |