In recent years, along with China's rapid development of economy, excavator was widely used in engineering construction, rescue, building, municipal administration, farmland, water conservancy etc., and every profession and trade is also increasingly high to the energy-conservation requirement of excavator.
For realizing the Energy Saving Control of excavator; Generally adopt control of hydraulic pressure minus flow and electronics rotating speed induction control technology both at home and abroad; These technology had once reduced the oil consumption of hydraulic crawler excavator significantly, but because the operating load of excavator own is changeable, caused diesel engine substantial deviation economic work district; Cause fuel utilization ratio not high, especially under the situation of high rotating speed, little load.The situation of changing load has determined under traditional control technology, to be difficult to further improve energy-saving effect.
Minus flow excavator control system Principles of Regulation are: the pressure before the control valve speed control muffler is caused the pumpage governor motion; Big more through the throttle orifice flow; Then pilot pressure is big more before the restriction; Explain that the flow that pump provides is not used by load fully, but oil sump tank, so pumpage is more little.The controlled pressure (minus flow feedback pressure) that is the pump stroking mechanism is inverse ratio with pumpage, and is as shown in Figure 1.
As shown in Figure 2, said minus flow excavator control system comprises: moment of torsion proportioning valve 11, permanent PCU Power Conditioning Unit 12 and minus flow adjusting device 13, it is used to control two main pumps of excavator, i.e. front pump and back pump.Said control system compares actual engine speed and rotating speed of target, falls fast situation according to motor, through regulating moment of torsion proportioning valve 11 electric currents; The maximum absorption torque of restrictive pump; Change pump delivery indirectly, thus the absorbed power of adjustment pump, the power match of realization pump and motor.
The major defect of above-mentioned minus flow excavator control system has:
(1). the discharge capacity of two main pumps can not independent regulation;
(2). can't realize that intelligent pressure cuts off function (wheel cylinder pressure cut off, variable pressure cut off), spill losses is bigger;
(3). the negative pressure signal that is used to feed back is the unnecessary pressure loss;
(4). regulate the method underaction of pump absorbed power and discharge capacity through the moment of torsion electromagnetic valve;
(5). according to present control mode, system does not have more potentiality can dig, and becomes the bottleneck of performance of further lifting excavator.
The specific embodiment
Below will combine accompanying drawing that the full power control system of plant equipment of the present invention is elaborated.
Need to prove that the plant equipment that full power control system of the present invention can be applicable to includes but not limited to: excavator, loader, land leveller, crane, rotary drilling rig, concrete mixer or the like.
See also Fig. 3, the full power control system of plant equipment of the present invention comprises: detecting unit, two main pump pressure sensors, engine operating parameter acquiring unit, two electric proportional pressure-reducing valves and control module.
Said detecting unit is used for the control pressure signal that the said plant equipment operating personnel of sensing send to two main pumps.If said plant equipment is provided with minus flow feedback hydraulic loop choke valve; Then as a kind of optimal way; Detecting unit can adopt two minus flow pressure sensors, and each minus flow pressure sensor can be provided with respect to a minus flow feedback hydraulic loop choke valve, with the pressure signal before the choke valve of the corresponding minus flow feedback hydraulic of sensing loop; The relation that can be inversely proportional to according to handle stroke and minus flow pressure signal is confirmed the demand of user to machine speed.As shown in Figure 4, minus flow pressure sensor 21 (the minus flow pressure sensor figure of another one pump does not show) is provided with respect to minus flow feedback hydraulic loop choke valve.
In addition; Said detecting unit can be used for the manipulation pressure in the said handle guide of sensing loop, for example respectively with respect to the operating grip setting of said plant equipment; Directly the manipulation pressure with handle guide loop compares, and gets and handles the pressure sum as control pressure signal.
In addition, the setting that it should be appreciated by those skilled in the art that said detecting unit is not with the above-mentioned limit that is depicted as.
Said two main pump pressure sensors are used to detect the pressure of two main pump outlets.As shown in Figure 4, main pump pressure sensor 22 (another one main pump pressure sensor figure does not show) is arranged on plant equipment, for example the output pressure mouth of excavator main pump.
Said engine operating parameter acquiring unit is arranged in the engine operation loop of said plant equipment, is used to obtain the power output and the rotating speed of said motor.For example, said engine operating parameter acquiring unit can comprise throttle actuator, and its feedback position according to throttle actuator can obtain power output and the rotating speed that starts function to provide.In addition, said engine operating parameter acquiring unit also can comprise engine speed sensor, is used for actual speed of sensing motor or the like.
It should be appreciated by those skilled in the art that the mode that said engine operating parameter acquiring unit obtains the running parameter of motor is not to exceed with said.
Said two electric proportional pressure-reducing valves are separately positioned on the controlled pressure mouth of two main pumps of plant equipment.As shown in Figure 4, electric proportional pressure-reducing valve 23 (another one electricity proportional pressure-reducing valve figure does not show) is arranged on plant equipment, for example the discharge capacity controlled pressure mouth of excavator main pump.
Said control module 24 is connected with said detecting unit, two main pump pressure sensors, engine operating parameter acquiring unit and two electric proportional pressure-reducing valves; The power that is used for said two main pumps of calculation of pressure of two main pumps outlets that two main pump control pressure signal, said two main pump pressure sensors according to said detecting unit institute sensing are detected; And based on the power output of said motor and rotating speed output control signal corresponding to said two electric proportional pressure-reducing valves, to realize control to said two main pump power.
The course of work of the full power control system of above-mentioned plant equipment is as shown in Figure 5, at first, and by the control pressure signal P of detecting unit according to two minus flow pressure sensor senses, two pumps
Ctr2, detect pressure P 1 and the P2 that two main pumps export by two main pump pressure sensors, subsequently, control module 24 is according to control pressure signal P
Ctr2And the pressure P 1 of two main pump pressure port calculates two pump power W with P2
PumpThen with the demand power W of pump
PumpWith the power output W that can provide motor at this moment
MotorCompare, result relatively has following three kinds of situation:
Show that promptly the demand power of pump exceeds the power output of motor, for avoiding motor because of overload stall even flame-out, control module can be with two pump delivery q
2Reduce.Subsequently, the electric proportional pressure-reducing valve that control module is scheduled to through inquiry is controlled the correspondence table of electric current and pumpage, can draw actual electric proportional pressure-reducing valve control electric current I
2, thus, output corresponding control current I
2To two electric proportional pressure-reducing valves to control two pumpages.
Show that the engine output of this moment exceeds the power of pump, control module can make engine output set according to the power of pump according to the thought of " what are used, what are given ", and tabling look-up draws W
PumpThe time corresponding engine speed N ' (N '＜N) as the new setting rotating speed of motor, calculate corresponding discharge capacity q according to engine speed again
1 ', q
2 ', make two pump works under big discharge capacity, efficient is higher, and can effectively reduce engine scuffing and noise, through inquiring about the predetermined electric proportional pressure-reducing valve control electric current and the correspondence table of pumpage, can draw actual electric proportional pressure-reducing valve control electric current I
1 ', I
2 ', thus, output corresponding control current I
1 ', I
2 'To two electric proportional pressure-reducing valves, engine speed is to N ' simultaneously.
Show that the power output of motor this moment just in time satisfies the demand of hydraulic system.Calculate two corresponding pump delivery q according to the present engine rotational speed N
1 ", q
1 ",, can draw actual electric proportional pressure-reducing valve control electric current I through inquiring about the predetermined electric proportional pressure-reducing valve control electric current and the correspondence table of pumpage
1 ", I
2 ", thus, output corresponding control current I
1 ", I
2 "To two electric proportional pressure-reducing valves to control two pumpages.
In sum, the full power control system of plant equipment of the present invention is compared with existing minus flow control system, and main advantage is:
(1). realize the independent regulation of double pump discharge capacity, regulated flexibly, improved the operating efficiency of pump.
(2). can realize the pressure cut off of intelligent alterable, system pressure is controlled under the cut-out pressure value of setting, reduce the draining loss of overflow valve.
(3). engine speed is regulated according to user's operational requirements automatically.
(4). pump often is operated in big discharge capacity, and efficient is high.
(5). the real realization " with what, what are given ", excavator more efficiently, more energy-conservation.
The foregoing description is just listed expressivity principle of the present invention and effect is described, but not is used to limit the present invention.Any personnel that are familiar with this technology all can make amendment to the foregoing description under spirit of the present invention and scope.Therefore, rights protection scope of the present invention should be listed like claims.