Summary of the invention
In view of this, the fault detection method and the device that provide a kind of high pressure oil pump cannot set up low rail pressure are provided main purpose of the present invention, when setting rail pressure and theoretical fuel delivery and be less than or equal to minimum value to continue to be greater than in actual rail pressure, determine that high pressure oil pump cannot set up the failure cause of low rail pressure.
To achieve these goals, the invention provides the fault detection method that a kind of high pressure oil pump cannot be set up low rail pressure, comprising:
In two closed loop rail pressure control systems, when the actual fuel flow that utilizes fuel gauging unit controls to flow into high pressure oil pump is during for minimum discharge, detect the first actual rail pressure of common rail pipe, described pair of closed loop rail pressure control system adopts rail pressure outer shroud feedback control and current inner loop feedback control;
If described the first actual rail pressure perseverance is greater than setting rail pressure, judge whether the theoretical fuel delivery of fuel gauging unit in described pair of closed loop rail pressure control system is less than or equal to minimum threshold;
If described theoretical fuel delivery is less than or equal to minimum threshold, detect the actual current of described fuel gauging unit;
If described actual current not in setting range, determines that drive circuit or the wire harness of described fuel gauging unit breaks down with the difference of setting electric current;
If the difference of described actual current and setting electric current is in setting range, control described fuel gauging unit to set dutycycle work, and detect the second actual rail pressure of described common rail pipe, described setting dutycycle is that maximum duty cycle adds setting side-play amount, and the fuel flow that described setting dutycycle and described fuel gauging unit controls enter high pressure oil pump is inversely proportional to;
If the amplitude of variation of described the second actual rail pressure is not less than setting threshold, determine that characteristic drift fault appears in described fuel gauging unit;
If the amplitude of variation of described the second actual rail pressure is less than setting threshold, there was a mechanical failure to determine described high pressure oil pump.
Preferably, in said method, if described theoretical fuel delivery is greater than minimum threshold, determine that rail pressure outer shroud control problem appears in described pair of closed loop rail pressure control system.
Preferably, in said method, described mechanical failure comprises: when described fuel gauging unit is closed, gap greatly or the zero oil mass hole of high pressure oil pump is too small or obstruction.
Preferably, said method also comprises:
If drive circuit or the wire harness of described fuel gauging unit break down, send the first alarm signal;
If characteristic drift fault appears in described fuel gauging unit, send the second alarm signal;
If there was a mechanical failure for described high pressure oil pump, send the 3rd alarm signal;
If rail pressure outer shroud control problem appears in described double closed-loop control system, send the 4th alarm signal.
Preferably, in said method, adopts pressure sensor detects the first actual rail pressure or the second actual rail pressure of described common rail pipe.
The present invention also provides a kind of high pressure oil pump cannot set up the Fail detecting apparatus of low rail pressure, comprising:
The first detection unit, be used in two closed loop rail pressure control systems, when the actual fuel flow that utilizes fuel gauging unit controls to flow into high pressure oil pump is during for minimum discharge, detect the first actual rail pressure of common rail pipe, described pair of closed loop rail pressure control system adopts rail pressure outer shroud feedback control and current inner loop feedback control;
The first judging unit, for judging whether perseverance is greater than setting rail pressure to described the first actual rail pressure;
The second judging unit, while being greater than setting rail pressure for described the first actual rail pressure perseverance obtaining in described the first judging unit judgement, judges whether the theoretical fuel delivery of fuel gauging unit in described pair of closed loop rail pressure control system is less than or equal to minimum threshold;
The second detection unit, while being less than or equal to minimum threshold for the described theoretical fuel delivery obtaining in described the second judging unit judgement, detects the actual current of described fuel gauging unit;
The 3rd judging unit, for judge described actual current with the difference of setting electric current whether in setting range;
The first determining unit, not in setting range time, determines that drive circuit or the wire harness of described fuel gauging unit breaks down with the difference of setting electric current for the described actual current that obtains in described the 3rd judging unit judgement;
Control unit, be used for when described the 3rd judging unit judges that the described actual current obtaining and the difference of setting electric current are in setting range, control described fuel gauging unit to set dutycycle work, described setting dutycycle is that maximum duty cycle adds setting side-play amount, and the fuel flow that described setting dutycycle and described fuel gauging unit controls enter high pressure oil pump is inversely proportional to;
Described the first detection unit, also, for controlling described fuel gauging unit at described control unit to set after dutycycle work, detects the second actual rail pressure of described common rail pipe;
The 4th judging unit, for judging whether the amplitude of variation of described the second actual rail pressure is less than setting threshold;
The second determining unit, for when described the 4th judging unit judges that the amplitude of variation of described the second actual rail pressure obtaining is not less than setting threshold, determines that characteristic drift fault appears in described fuel gauging unit;
The 3rd determining unit, for when described the 4th judging unit judges that the amplitude of variation of described the second actual rail pressure obtaining is less than setting threshold, there was a mechanical failure to determine described high pressure oil pump.
Preferably, said apparatus also comprises:
The 4th determining unit, while being greater than minimum threshold for the described theoretical fuel delivery obtaining in described the second judging unit judgement, determines that rail pressure outer shroud control problem appears in described pair of closed loop rail pressure control system.
Preferably, in said apparatus, described mechanical failure comprises: when described fuel gauging unit is closed, gap greatly or the zero oil mass hole of high pressure oil pump is too small or obstruction.
Preferably, said apparatus also comprises:
The first transmitting element, while breaking down for the drive circuit of the described fuel gauging unit determined in described the first determining unit or wire harness, sends the first alarm signal;
The second transmitting element, while there is characteristic drift fault for the described fuel gauging unit of determining in described the second determining unit, sends the second alarm signal;
The 3rd transmitting element, when there was a mechanical failure for the described high pressure oil pump determined in described the 3rd determining unit, sends the 3rd alarm signal;
The 4th transmitting element, while there is rail pressure outer shroud control problem for the described double closed-loop control system of determining in described the 4th determining unit, sends the 4th alarm signal.
Preferably, in said apparatus, described the first detection unit, detects the first actual rail pressure or the second actual rail pressure of described common rail pipe specifically for adopts pressure sensor.
Visible, high pressure oil pump of the present invention cannot be set up fault detection method and the device of low rail pressure, under the unloaded idling operation of motor, if rail pressure is in closed loop control, and actual rail pressure is lasting bigger than normal and theoretical fuel delivery is less than or equal to minimum value, can get rid of rail pressure outer shroud control problem; If current closed-loop error in the reasonable scope, get rid of fuel gauging unit hardware circuit and wire harness problem; Utilize open loop diverter switch to set open loop dutycycle and add side-play amount for maximum duty cycle, if actual rail pressure amplitude of variation is less, get rid of fuel gauging element characteristics drifting problem, above three kinds of reasons are all excluded can be confirmed as high pressure oil pump mechanical reason and cause setting up low rail pressure, is generally high pressure oil pump zero oil mass hole too small or stop up.Visible, the present invention can accurately distinguish the fault mode that cannot set up low rail pressure, thereby is convenient to the eliminating of fault.
Embodiment
For making object, technological scheme and the advantage of the embodiment of the present invention clearer, below in conjunction with the accompanying drawing in the embodiment of the present invention, technological scheme in the embodiment of the present invention is clearly and completely described, obviously, described embodiment is the present invention's part embodiment, rather than whole embodiments.Embodiment based in the present invention, those of ordinary skills, not making the every other embodiment who obtains under creative work prerequisite, belong to the scope of protection of the invention.
Under paper, in which kind of situation, need to set up low rail pressure:
Motor is when the slow-speed of revolution or low-load, and the required fuel injection quantity of oil sprayer is less, now needs to utilize high pressure oil pump to set up lower common rail pipe pressure (low rail pressure), when common rail pipe pressure is lower, can controls more accurately oil sprayer and carry out oil spout.Because when the required fuel injection quantity of oil sprayer is less, if the pressure in common rail pipe is larger, common rail pipe discharge moment fuel injection quantity will be larger, will more difficult control for required low fuel injection quantity, so now need to utilize high pressure oil pump to set up low rail pressure, reduce the pressure in common rail pipe by reducing the amount of fuel being flowed in common rail pipe by high pressure oil pump.
Shown in Figure 4, Fig. 4 is the schematic flow sheet that a kind of high pressure oil pump provided by the invention cannot be set up the fault detection method of low rail pressure, and the step that realizes the method is as follows:
S401: in two closed loop rail pressure control systems, when the actual fuel flow that utilizes fuel gauging unit controls to flow into high pressure oil pump is during for minimum discharge, detect the first actual rail pressure of common rail pipe.
Described pair of closed loop rail pressure control system is the block diagram shown in Fig. 2, and this pair of closed loop rail pressure control system adopts rail pressure outer shroud feedback control and current inner loop feedback control.
Described fuel gauging unit is to control the proportional electromagnetic valve that enters high pressure oil pump import fuel flow, fuel gauging unit controls characteristic as shown in Figure 3, it is in the nature electromagnetic proportional valve, this valve feature is for reducing along with electric current increases fuel delivery, and electric current is proportional to dutycycle, therefore the larger fuel delivery of dutycycle is less, and the characteristic of fuel gauging unit itself can be drifted about along with service time.
Can utilize pressure transducer to detect high pressure co-rail system common rail pipe pressure, to obtain the first actual rail pressure of common rail pipe.
S402: if the first actual rail pressure perseverance of described common rail pipe is greater than setting rail pressure, whether the theoretical fuel delivery that judges fuel gauging unit in described pair of closed loop rail pressure control system is less than or equal to minimum threshold, if so, performs step S403, if not, perform step S410.
Illustrate, if the setting rail pressure under current working (the low rail pressure of the common rail pipe that this setting rail pressure is the required foundation of system) is 10MPa, but after the two closed loop rail pressure control systems shown in Fig. 2 regulate, the first actual rail pressure of common rail pipe continues to be greater than setting rail pressure, and drop to, do not set rail pressure place, knownly currently cannot set up required low rail pressure, now should detect the reason that cannot set up low rail pressure, and fault is investigated.
By judging whether the theoretical fuel delivery of exporting in two closed loop rail pressure control systems is less than or equal to minimum threshold, if the first actual rail pressure perseverance is greater than setting rail pressure and described theoretical fuel delivery is greater than minimum threshold, proof high pressure oil pump is controlled surplus in addition, can control and continue to regulate by rail pressure outer shroud, by controlling described fuel gauging unit, to reduce the fuel flow that enters high pressure oil pump, thereby can reduce the amount of fuel flowing in common rail pipe, finally make the first actual rail pressure of common rail pipe approach setting rail pressure; So, when the first actual rail pressure continues to be greater than when setting rail pressure and theoretical fuel feeding and being greater than minimum threshold, can determine that it is outer shroud control problem that high pressure oil pump cannot be set up the failure cause of low rail pressure, now, after determining failure cause, can stop faut detection, and by outer shroud is controlled and improved, to realize the object of setting up low rail pressure.
But if the theoretical fuel delivery of fuel gauging unit is less than or equal to minimum threshold in two closed loop rail pressure control system, can get rid of outer shroud control problem, now performs step 5403 and with continuation, fault is detected.
S403: the actual current that detects described fuel gauging unit.
S404: whether the actual current that judges described fuel gauging unit and the difference of setting electric current in setting range, if so, perform step S405, if not, performs step S 409.
Because no matter whether the first actual rail pressure follows setting rail pressure, as long as described fuel gauging unit hardware circuit and wire harness fault-free, the electric current of fuel gauging unit just can well be followed.So when current following error (actual current and the difference of setting electric current) when (in setting range), illustrates that drive circuit or the wire harness of described fuel gauging unit do not break down in rational margin of error; Otherwise, if when current following error (actual current and the difference of setting electric current) is not in rational margin of error when (in setting range), drive circuit or wire harness that fuel gauging unit is described break down, now, can the drive circuit of fuel gauging unit or wire harness be detected and be repaired after determining failure cause.
S405: control described fuel gauging unit to set dutycycle work, and detect the second actual rail pressure of described common rail pipe, described setting dutycycle is that maximum duty cycle adds setting side-play amount, and the fuel flow that described setting dutycycle and described fuel gauging unit controls enter high pressure oil pump is inversely proportional to.
Can utilize above-mentioned pressure transducer to detect high pressure co-rail system common rail pipe pressure, to obtain the second actual rail pressure of common rail pipe.
S406: whether the amplitude of variation that judges described the second actual rail pressure is less than setting threshold, if so, performs step S407, if not, performs step S408.
If described fuel gauging cell operation duty cycle adjustment is arrived maximum, and on the basis of maximum duty cycle, increase certain side-play amount, now detect the amplitude of variation of the second actual rail pressure of common rail pipe, if the amplitude of variation of the second actual rail pressure is large (amplitude of variation of the second actual rail pressure is not less than setting threshold), prove that fuel gauging unit still has control surplus, fuel delivery and calibration curve and the characteristic curve after characteristic drift between electric current (or dutycycle) that fuel gauging unit is described are inconsistent, now, can determine that characteristic drift fault appears in described fuel gauging unit, can revise and come by the demarcation again of curve in this case.
If but the amplitude of variation of the second actual rail pressure less (amplitude of variation of the second actual rail pressure is less than setting threshold), and now got rid of the above-mentioned three kinds of failure causes that cannot set up low rail pressure, just can determine it is that there was a mechanical failure for high pressure oil pump.
S407: there was a mechanical failure to determine described high pressure oil pump.
Wherein, the mechanical failure of described high pressure oil pump comprises: when described fuel gauging unit is closed, gap greatly or the zero oil mass hole of high pressure oil pump is too small or obstruction.
Because fuel gauging unit generally cannot be closed completely, when needs are set up low rail pressure, unnecessary fluid when fuel gauging unit is closed need to reflux and could set up low pressure through zero passage oil mass hole.
S408: determine that characteristic drift fault appears in described fuel gauging unit.
S409: drive circuit or the wire harness of determining described fuel gauging unit break down.
S410: determine that rail pressure outer shroud control problem appears in described pair of closed loop rail pressure control system.
High pressure co-rail system cannot be set up low rail pressure four large class reasons: rail pressure outer shroud control problem; Fuel gauging unit PWM drive circuit or wire harness have problem; Fuel gauging element characteristics curves shift; High pressure oil pump mechanical problem.Can different alarm signals be set for different fault modes, so that fault mode is distinguished, thereby carry out malfunction elimination for concrete fault.Specific as follows:
If drive circuit or the wire harness of 1 described fuel gauging unit break down, send the first alarm signal;
If characteristic drift fault appears in 2 described fuel gauging unit, send the second alarm signal;
If there was a mechanical failure for 3 described high pressure oil pumps, send the 3rd alarm signal;
If rail pressure outer shroud control problem appears in 4 described double closed-loop control systems, send the 4th alarm signal.
High pressure oil pump of the present invention cannot be set up the fault detection method of low rail pressure, under the unloaded idling operation of motor, if rail pressure in closed loop control, and actual rail pressure continues bigger than normal and theoretical fuel delivery and is less than or equal to minimum value, can get rid of rail pressure outer shroud control problem; If current closed-loop error in the reasonable scope, get rid of fuel gauging unit hardware circuit and wire harness problem; Utilize open loop diverter switch to set open loop dutycycle and add side-play amount for maximum duty cycle, if actual rail pressure amplitude of variation is less, get rid of fuel gauging element characteristics drifting problem, above three kinds of reasons are all excluded can be confirmed as high pressure oil pump mechanical reason and cause setting up low rail pressure, is generally high pressure oil pump zero oil mass hole too small or stop up.Visible, the present invention can accurately distinguish the fault mode that cannot set up low rail pressure, thereby is convenient to the eliminating of fault.
Shown in Figure 5, Fig. 5 is the structural representation that a kind of high pressure oil pump provided by the invention cannot be set up the Fail detecting apparatus of low rail pressure, and Fig. 5 cannot set up with the high pressure oil pump shown in Fig. 4 the device that the fault detection method of low rail pressure is corresponding, and this device comprises:
The first detection unit 1, be used in two closed loop rail pressure control systems, when the actual fuel flow that utilizes fuel gauging unit controls to flow into high pressure oil pump is during for minimum discharge, detect the first actual rail pressure of common rail pipe, described pair of closed loop rail pressure control system adopts rail pressure outer shroud feedback control and current inner loop feedback control;
The first judging unit 2, for judging whether perseverance is greater than setting rail pressure to described the first actual rail pressure;
The second judging unit 3, while being greater than setting rail pressure for described the first actual rail pressure perseverance obtaining in described the first judging unit 2 judgements, judges whether the theoretical fuel delivery of fuel gauging unit in described pair of closed loop rail pressure control system is less than or equal to minimum threshold;
The second detection unit 4, while being less than or equal to minimum threshold for the described theoretical fuel delivery obtaining in described the second judging unit 3 judgements, detects the actual current of described fuel gauging unit;
The 3rd judging unit 5, for judge described actual current with the difference of setting electric current whether in setting range;
The first determining unit 6, for when described the 3rd judging unit 5 judges that the described actual current obtaining and the difference of setting electric current be not in setting range, determines that drive circuit or the wire harness of described fuel gauging unit breaks down;
Control unit 7, for when described the 3rd judging unit 5 judges that the described actual current obtaining and the difference of setting electric current are in setting range, control described fuel gauging unit to set dutycycle work, described setting dutycycle is that maximum duty cycle adds setting side-play amount, and the fuel flow that described setting dutycycle and described fuel gauging unit controls enter high pressure oil pump is inversely proportional to;
Described the first detection unit 1, also, for controlling described fuel gauging unit at described control unit to set after dutycycle work, detects the second actual rail pressure of described common rail pipe;
The 4th judging unit 8, for judging whether the amplitude of variation of described the second actual rail pressure is less than setting threshold;
The second determining unit 9, for when described the 4th judging unit 8 judges that the amplitude of variation of described the second actual rail pressure obtaining is not less than setting threshold, determines that characteristic drift fault appears in described fuel gauging unit;
The 3rd determining unit 10, for when described the 4th judging unit 8 judges that the amplitude of variation of described the second actual rail pressure obtaining is less than setting threshold, there was a mechanical failure to determine described high pressure oil pump.
The 4th determining unit 11, while being greater than minimum threshold for the described theoretical fuel delivery obtaining in described the second judging unit 3 judgements, determines that rail pressure outer shroud control problem appears in described pair of closed loop rail pressure control system.
Wherein, described the first detection unit 1, detects the first actual rail pressure or the second actual rail pressure of described common rail pipe specifically for adopts pressure sensor.
Wherein, described mechanical failure comprises: when described fuel gauging unit is closed, gap greatly or the zero oil mass hole of high pressure oil pump is too small or obstruction.
In addition, said apparatus also comprises:
The first transmitting element 12, while breaking down for the drive circuit of the described fuel gauging unit determined in described the first determining unit 6 or wire harness, sends the first alarm signal;
The second transmitting element 13, while there is characteristic drift fault for the described fuel gauging unit of determining in described the second determining unit 9, sends the second alarm signal;
The 3rd transmitting element 14, when there was a mechanical failure for the described high pressure oil pumps determined in described the 3rd determining unit 10, sends the 3rd alarm signal;
The 4th transmitting element 15, while there is rail pressure outer shroud control problem for the described double closed-loop control system of determining in described the 4th determining unit 11, sends the 4th alarm signal.
High pressure oil pump of the present invention cannot be set up the Fail detecting apparatus of low rail pressure, under the unloaded idling operation of motor, if rail pressure in closed loop control, and actual rail pressure continues bigger than normal and theoretical fuel delivery and is less than or equal to minimum value, can get rid of rail pressure outer shroud control problem; If current closed-loop error in the reasonable scope, get rid of fuel gauging unit hardware circuit and wire harness problem; Utilize open loop diverter switch to set open loop dutycycle and add side-play amount for maximum duty cycle, if actual rail pressure amplitude of variation is less, get rid of fuel gauging element characteristics drifting problem, above three kinds of reasons are all excluded can be confirmed as high pressure oil pump mechanical reason and cause setting up low rail pressure, is generally high pressure oil pump zero oil mass hole too small or stop up.Visible, the present invention can accurately distinguish the fault mode that cannot set up low rail pressure, thereby is convenient to the eliminating of fault.
Also it should be noted that, in this article, relational terms such as the first and second grades is only used for an entity or operation to separate with another entity or control panel, and not necessarily requires or imply and between these entities or operation, have the relation of any this reality or sequentially.And, term " comprises ", " comprising " or its any other variant are intended to contain comprising of nonexcludability, thereby the process, method, article or the equipment that make to comprise a series of key elements not only comprise those key elements, but also comprise other key elements of clearly not listing, or be also included as the intrinsic key element of this process, method, article or equipment.The in the situation that of more restrictions not, the key element being limited by statement " comprising ... ", and be not precluded within process, method, article or the equipment that comprises described key element and also have other identical element.
Above-mentioned explanation to the disclosed embodiments, makes professional and technical personnel in the field can realize or use the present invention.To these embodiments' multiple modification, will be apparent for those skilled in the art, General Principle as defined herein can, in the situation that not departing from the spirit or scope of the present invention, realize in other embodiments.Therefore, the present invention will can not be restricted to these embodiments shown in this article, but will meet the widest scope consistent with principle disclosed herein and features of novelty.