CN104005818A - Current control method and system for urea nozzle - Google Patents
Current control method and system for urea nozzle Download PDFInfo
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- CN104005818A CN104005818A CN201410190776.4A CN201410190776A CN104005818A CN 104005818 A CN104005818 A CN 104005818A CN 201410190776 A CN201410190776 A CN 201410190776A CN 104005818 A CN104005818 A CN 104005818A
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- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 title claims abstract description 138
- 239000004202 carbamide Substances 0.000 title claims abstract description 138
- 238000000034 method Methods 0.000 title claims abstract description 26
- 238000005070 sampling Methods 0.000 claims abstract description 61
- 238000006243 chemical reaction Methods 0.000 claims abstract description 23
- 230000000087 stabilizing effect Effects 0.000 claims description 3
- 230000004044 response Effects 0.000 abstract description 6
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 3
- 230000006641 stabilisation Effects 0.000 description 3
- 238000011105 stabilization Methods 0.000 description 3
- 238000010531 catalytic reduction reaction Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000036962 time dependent Effects 0.000 description 2
- 238000003745 diagnosis Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
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Abstract
The invention provides a current control method and system for a urea nozzle. The system comprises a sampling module, a controller, a digital-analog conversion module, a threshold value setting module and a comparator. The sampling module converts an actual working current of the urea nozzle into a voltage to be fed back to the comparator. The controller converts a target current value into a target voltage value to be output to the digital-analog conversion module. The target current value within the first period of time is a peak current value, and the target current value formed after the first period of time is a maintaining current value. The digital-analog conversion module converts the target voltage value into an analog signal to be output to the comparator. The upper threshold value and the lower threshold value of the comparator are set to be a first threshold value and a second threshold value through the threshold setting module respectively. The comparator controls a voltage control switching tube of the urea nozzle to be switched off when the actual working voltage is larger than the first threshold value, and controls the switching tube to be switched on when the actual working voltage is smaller than the second threshold value. According to the current control method and system for the urea nozzle, the state of the voltage control switching tube of the urea nozzle can be controlled in a hardware mode, the response speed is higher, and the system reliability is improved.
Description
Technical field
The present invention relates to Motor Control Field, especially relate to a kind of current control method and system of urea nozzle.
Background technique
SCR (Selective Catalytic Reduction, selective catalytic reduction) system is used for realizing engines tail gas disposal, to reduce the discharge of nitrogen oxide.Wherein, urea nozzle is the critical component of SCR system, is mainly used in urea to inject exhaust duct from urea box.
The operating current waveform more complicated of the urea nozzle of SCR system needs larger operating current in the time opening, and needs afterwards less electric current to maintain.Therefore, how realizing the control to the operating current of urea nozzle in SCR system, is the problem that people are relatively concerned about.
At present, in the time that the operating current of urea nozzle is controlled, main by the single-chip microcomputer collecting work electric current with Reaction function, by the controlled signal of computing of single-chip microcomputer inside, to control the on state of voltage cut-out pipe of urea nozzle.Obviously, this mode need to be with the single-chip microcomputer of Reaction function by the controlled signal of internal arithmetic, and speed of response is slower, has reduced the reliability of system simultaneously.
Summary of the invention
The technical problem that the present invention solves is to provide a kind of current control method and system of urea nozzle, to realize the reliability that improves speed of response and improve system.
For this reason, the technological scheme of technical solution problem of the present invention is:
The invention provides a kind of current control system of urea nozzle, described system comprises:
Sampling module, after the real work current conversion of described urea nozzle is real work voltage, exports the first input end of comparator to;
Controller, for the target current value of described urea nozzle is converted to target voltage values, exports described target voltage values to D/A converter module; In first period of wherein starting working in described urea nozzle, the target current value of described urea nozzle is peak current value, and after described the first period, the target current value of described urea nozzle is for maintaining current value;
D/A converter module, for described target voltage values is converted to after analogue signal, exports the second input end of described comparator to;
Threshold value setting module, is respectively first threshold and Second Threshold for the upper lower threshold value that described comparator is set; Wherein, described first threshold is greater than described target voltage values, and described Second Threshold is less than described target voltage values;
Comparator, for in the time that described real work voltage is greater than described first threshold, output terminal output first controls signal to the voltage cut-out pipe of described urea nozzle, in the time that described real work voltage is less than described Second Threshold, output terminal output second controls signal to the voltage cut-out pipe of described urea nozzle;
Wherein, switching tube turn-offs described in described the first control signal control, switching tube conducting described in described the second control signal control.
Preferably, described system also comprises: diagnostic module;
Described diagnostic module is for judging according to the real work voltage of the working state of described switching tube and the output of described sampling module whether described system breaks down.
Preferably, described system also comprises: the first voltage follower;
Described the first voltage follower is arranged between described comparator and described switching tube, for after the signal of described comparator output is isolated and amplifying, exports described switching tube to.
Preferably, described system also comprises: second voltage follower;
Described second voltage follower is arranged between described comparator and described sampling module, for after the real work voltage of described sampling module output is isolated and amplifying, exports described comparator to.
Preferably, described system also comprises: reference diode;
Described reference diode is arranged between described comparator and described switching tube, for the signal of described comparator output is carried out, after voltage stabilizing, exporting described switching tube to.
Preferably, described sampling module comprises sampling resistor and voltage acquisition module; The electric current that described sampling resistor flows through is the real work electric current of described urea nozzle;
Described voltage acquisition module is for gathering the voltage at described sampling resistor two ends, as extremely described comparator of described real work Voltage-output.
Preferably, described threshold value setting module comprises the first resistance and the second resistance;
Described the first resistance is arranged between described sampling module and the first input end of described comparator, and described the second resistance is arranged between the first input end and described output terminal of described comparator.
The invention provides a kind of current control method of urea nozzle, described method comprises:
After sampling module is real work voltage by the real work current conversion of described urea nozzle, export the first input end of comparator to;
The target current value of described urea nozzle is converted to target voltage values by controller, exports described target voltage values to D/A converter module; In first period of wherein starting working in described urea nozzle, the target current value of described urea nozzle is peak current value, and after described the first period, the target current value of described urea nozzle is for maintaining current value;
D/A converter module is converted to described target voltage values after analogue signal, exports the second input end of described comparator to;
The upper lower threshold value that threshold value setting module arranges described comparator is first threshold and Second Threshold; Wherein, described first threshold is greater than described target voltage values, and described Second Threshold is less than described target voltage values;
Described comparator is in the time that described real work voltage is greater than described first threshold, output terminal output first controls signal to the voltage cut-out pipe of described urea nozzle, in the time that described real work voltage is less than described Second Threshold, output terminal output second controls signal to the voltage cut-out pipe of described urea nozzle;
Wherein, switching tube turn-offs described in described the first control signal control, switching tube conducting described in described the second control signal control.
Preferably, the current control system of urea nozzle comprises: described sampling module, described controller, described D/A converter module, described threshold value setting module, described comparator and diagnostic module;
Described method also comprises:
Described diagnostic module judges according to the real work voltage of the working state of described switching tube and the output of described sampling module whether described system breaks down.
Preferably, described method also comprises:
By the first voltage follower, the signal of described comparator output is isolated and amplify after export described switching tube to; And/or
By second voltage follower, the real work voltage of described sampling module output is isolated and amplify after export described comparator to.
Known by technique scheme, in the embodiment of the present invention, sampling module feeds back to comparator after the real work current conversion of urea nozzle is become to real work voltage, target current value is converted to target voltage values by controller, and after D/A converter module converts analogue signal to, also export comparator to.And the Second Threshold that threshold value setting module is set to the upper lower threshold value of comparator to be respectively greater than the first threshold of target voltage values and is less than target voltage values, therefore in the time that the real work voltage of sampling module sampling is greater than first threshold, the voltage cut-out pipe of comparator control urea nozzle turn-offs, thereby reduce the operating current of urea nozzle, in the time that the real work voltage of sampling module sampling is less than Second Threshold, the voltage cut-out pipe of comparator control urea nozzle is opened, thereby the operating current of the urea nozzle that raise, therefore ensured that the real work current stabilization of urea nozzle is near target current value.And within first period of starting working in urea nozzle, target current value is set to peak current value, thereby the real work electric current of controlling urea nozzle maintains near of Peak current, and after the first period, target current value is set to maintain current value, thereby the real work electric current of controlling urea nozzle maintains near that maintains electric current, realizes the demand of the operating current of urea nozzle.Visible the present invention is by the on state of the voltage cut-out pipe of hardware mode control urea nozzle, and without controller internal arithmetic, therefore speed of response is faster, has improved the reliability of system.
Brief description of the drawings
Fig. 1 is the oscillogram of the operating current of urea nozzle;
Fig. 2 is the structural representation of the specific embodiment of the current control system of urea nozzle of the present invention;
Fig. 3 is a kind of preferred circuit figure of sampling module provided by the invention;
Fig. 4 is a kind of preferred circuit figure of threshold value setting module provided by the invention;
Fig. 5 is a kind of preferred structure figure of urea nozzle current control system provided by the invention;
Fig. 6 is the circuit diagram of the reference diode of preferred setting provided by the invention;
Fig. 7 is the schematic flow sheet of the specific embodiment of the current control method of urea nozzle of the present invention.
Embodiment
The operating current waveform more complicated of the urea nozzle of SCR system, as shown in Figure 1, urea nozzle needs larger operating current (Peak electric current) in the time opening, and needs afterwards less electric current to maintain (Hold electric current).Therefore, how realizing the control to the operating current of urea nozzle in SCR system, is the problem that people are relatively concerned about.
At present, in the time that the operating current of urea nozzle is controlled, main by the single-chip microcomputer collecting work electric current with Reaction function, by the computing of single-chip microcomputer inside, the on state of output signal control urea nozzle switching tube.Obviously, this mode need to be with the single-chip microcomputer internal arithmetic of Reaction function, and speed of response is slower, has reduced the reliability of system simultaneously.
In addition, this mode also has following shortcoming:
The problem such as 1, the low and precision of current Reaction function ubiquity precision is non-adjustable.
2, need to select the single-chip microcomputer with Reaction function, cause the restriction in type selecting, cost is higher.
Refer to Fig. 2, the invention provides the specific embodiment of the current control system of urea nozzle, the present embodiment specifically comprises: sampling module 101, controller 102, D/A converter module 103, threshold value setting module 104 and comparator 105.
Sampling module 101, after the real work current conversion of urea nozzle is real work voltage, exports the first input end of comparator 105 to.
Sampling module 101 can Real-time Collection urea nozzle real work electric current, and by real work electric current according to a preset ratio, be converted to corresponding real work voltage.
Particularly, as shown in Figure 3, sampling module 101 can comprise sampling resistor Rc and voltage acquisition module 1001; The electric current that sampling resistor Rc flows through is the real work electric current of urea nozzle; Voltage acquisition module 1011 is for gathering the voltage at sampling resistor Rc two ends, as real work Voltage-output to comparator 105.Voltage acquisition module 1001 is specifically as follows voltage acquisition chip, example chip I NA193AIDBVR as shown in Figure 3.Now the magnitude of voltage of real work voltage is the product of the current value of real work electric current and the resistance of sampling resistor.As shown in Figure 3, it is 0.1 ohm that Rc can be set to example.
Controller 102, for the target current value of urea nozzle is converted to target voltage values, exports target voltage values to D/A converter module 103; In first period of wherein starting working in urea nozzle, the target current value of urea nozzle is peak current value, and after the first period, the target current value of urea nozzle is for maintaining current value.
When target current value is converted to target voltage values by controller 102, can be according to a preset ratio, this preset ratio and sampling module 101 in the time of conversion real work electric current and real work voltage based on preset ratio relevant.Controller can be specifically MCU.
Wherein, when the first period was opened by urea nozzle, need the Time dependent of large current work.And the current value of peak current value needed large electric current when to be urea nozzle open maintains current value and is the current value of needed less electric current after urea nozzle.
D/A converter module 103, for target voltage values is converted to after analogue signal, exports the second input end of comparator to.
D/A converter module 103 is specifically as follows DAC chip, for example a DAC121S101.
Threshold value setting module 104, is respectively first threshold and Second Threshold for the upper lower threshold value that comparator is set; Wherein, first threshold is greater than target voltage values, and Second Threshold is less than target voltage values.
What the first input end of comparator was inputted is the target voltage signal after digital-to-analog conversion, and the magnitude of voltage of this signal is target voltage values.Threshold value setting module 104 can be adjusted two upper lower threshold values of comparator, and target voltage values is in the threshold range of these two threshold value compositions.
As shown in Figure 4, threshold value setting module 104 can comprise the first resistance R 1 and the second resistance R 2.Comparator has first input end 3, the second input end 2 and output terminal 1.Wherein, the first resistance R 1 is arranged between the first input end 3 of sampling module 101 and comparator, and the second resistance R 2 is arranged between the first input end 3 and output terminal 1 of comparator.By adjusting the resistance of the first resistance R 1 and the second resistance R 2, just can realize the adjustment to two of comparator upper lower threshold values.As shown in Figure 4, the first resistance R 1 can be 1k ohm to example, and the second resistance R 2 can be 10k ohm.
Comparator 105, for in the time that real work voltage is greater than first threshold, output terminal output first controls signal to the voltage cut-out pipe 106 of urea nozzle, and in the time that real work voltage is less than Second Threshold, output terminal output second controls signal to the voltage cut-out pipe 106 of urea nozzle.Wherein, the voltage cut-out pipe 106 of the first control signal control urea nozzle turn-offs, voltage cut-out pipe 106 conductings of the second control signal control urea nozzle.
Comparator 105 has two input ends: first input end, the second input end, and an output terminal.Wherein, the second input end connects D/A converter module 103, and first input end connects sampling module 101, and goes up lower threshold values by threshold value setting module 104 to two of comparator 105: first threshold and Second Threshold are adjusted.Therefore, when the real work voltage being sent by sampling module 101 receiving when the first input end of comparator 105 is greater than first threshold, illustrate that now the real work electric current of urea nozzle exceeds target operating current more, therefore the output terminal of comparator 105 output first controls signal to the voltage cut-out pipe 106 of urea nozzle, thereby close the voltage cut-out pipe 106 of urea nozzle, to reduce real work electric current.When the real work voltage being sent by sampling module 101 receiving when the first input end of comparator 105 is less than Second Threshold, illustrate that now the real work electric current of urea nozzle is more lower than target operating current, therefore the output terminal of comparator 105 output second controls signal to the voltage cut-out pipe 106 of urea nozzle, thereby the voltage cut-out pipe 106 of conducting urea nozzle, to increase real work electric current, the real work current stabilization that has ensured urea nozzle by above-mentioned adjustment is near target current value.
Wherein, if real work voltage between first threshold and Second Threshold, comparator 105 can keep current output.
Comparator 105 is specifically as follows hysteresis comparator.
Known by technique scheme, in the embodiment of the present invention, acquisition module 101 by the real work Voltage-output of urea nozzle to comparator 105, target current value is converted to target voltage values by controller 102, and convert to after analogue signal through D/A converter module 103, also export comparator 105 to.And the Second Threshold that threshold value setting module 104 is set to the upper lower threshold value of comparator 105 to be respectively greater than the first threshold of target voltage values and is less than target voltage values, when the real work voltage of therefore sampling when sampling module 101 is greater than first threshold, the voltage cut-out pipe 106 that comparator 105 is controlled urea nozzle turn-offs, thereby reduce the operating current of urea nozzle, when the real work voltage of sampling when sampling module 101 is less than Second Threshold, comparator 105 is controlled the voltage cut-out pipe 106 of urea nozzle and is opened, thereby the operating current of the urea nozzle that raise, therefore ensured that the real work current stabilization of urea nozzle is near target current value.And within first period of starting working in urea nozzle, target current value is set to peak current value, thereby the real work electric current of controlling urea nozzle maintains near of Peak current, and after the first period, target current value is set to maintain current value, thereby the real work electric current of controlling urea nozzle maintains near that maintains electric current, realizes the demand of the operating current of urea nozzle.Visible the present invention is by the on state of the voltage cut-out pipe of hardware mode control urea nozzle, and without controller internal arithmetic, therefore speed of response is faster, has improved the reliability of system.
In addition, the present invention also has the following advantages:
1, no longer adopt the single-chip microcomputer with Reaction function, be therefore no longer subject to the accuracy limitations of Reaction function.
2, can module 104 adjustment precision be flexibly set passing threshold, the voltage disturbance of filtering sampling module,
3, without the single-chip microcomputer with Reaction function, reduced cost.
4, realized the operating current of flexible adjustment urea nozzle by adjustment aim current value.
In the present embodiment, acquisition module 101 can be Real-time Collection real work voltage, and exports comparator 105 to, thereby the system of the present embodiment is controlled the operating current of urea nozzle in real time.
Controller 102 can also be used for directly controlling the voltage cut-out pipe 106 of urea nozzle and close.For example, in the time that system need to be turn-offed urea nozzle, assign and turn-off order by MCU, shutoff voltage control switch pipe 106, the electric current continuous decrease of urea nozzle, finally reaches the function of shutoff.
As shown in Figure 5, the system of the present embodiment can also comprise diagnostic module 501.Diagnostic module 501 judges for the real work voltage of exporting according to the working state of the voltage cut-out pipe 106 of urea nozzle and sampling module 101 whether the system of the present embodiment breaks down.For example, if the high output terminal that diagnostic module is judged urea nozzle is high level always, and real work voltage is while being greater than first threshold voltage, judges and is shorted to power failure; If the high output terminal that diagnostic module is judged urea nozzle is low level always, and real work voltage is while being less than Second Threshold voltage, judges the open fault of urea nozzle.
Wherein, urea nozzle has two output pins, i.e. two output terminals, and an output terminal is for outflow of bus current, i.e. high output terminal.
Diagnostic module 105 can be that the result of diagnosis is sent to controller 102, is judged according to this result by controller 102.
As shown in Figure 5, in order further signal to be adjusted, the system of the present embodiment can also comprise: the first voltage follower 502, the first voltage follower 502 is arranged between the voltage cut-out pipe 106 of comparator 105 and urea nozzle, after isolating and amplify for signal that comparator 105 is exported, export the voltage cut-out pipe 106 of urea nozzle to.
As shown in Figure 5, in order further signal to be adjusted, the system of the present embodiment can also comprise: second voltage follower 503, second voltage follower 503 is arranged between comparator 105 and sampling module 101, after isolating and amplify for real work voltage that sampling module 101 is exported, export comparator 105 to.It should be noted that, if now the threshold value setting module of the present embodiment is specially the first resistance and the second resistance, now the first resistance is arranged between second voltage follower 503 and comparator 105.
As shown in Figure 6, can also comprise at the present embodiment: reference diode D1; Reference diode D1 is arranged between the voltage cut-out pipe 106 of comparator 105 and urea nozzle, carries out after voltage stabilizing for the signal that comparator 105 is exported, and exports the voltage cut-out pipe 106 of urea nozzle to.
Introduce the current control system of urea nozzle provided by the invention above, corresponding, the present invention also provides the current control method of urea nozzle, and method provided by the invention can be in the specific embodiment of arbitrary system provided by the invention.
Refer to Fig. 7, the invention provides the specific embodiment of the current control method of urea nozzle, the present embodiment comprises:
S701: after sampling module is real work voltage by the real work current conversion of urea nozzle, export the first input end of comparator to.
In this step, sampling module can be to be specifically real work voltage by a sampling resistor by real work current conversion.
S702: the target current value of urea nozzle is converted to target voltage values by controller, exports target voltage values to D/A converter module; In first period of wherein starting working in urea nozzle, the target current value of urea nozzle is peak current value, and after the first period, the target current value of urea nozzle is for maintaining current value.
When being opened by urea nozzle, needs the first period the Time dependent of large current work.
S703: D/A converter module is converted to target voltage values after analogue signal, exports the second input end of comparator to.
S704: the upper lower threshold value that threshold value setting module arranges comparator is first threshold and Second Threshold; Wherein, first threshold is greater than target voltage values, and Second Threshold is less than target voltage values.
What the second input end of comparator was inputted is the target voltage signal after digital-to-analog conversion, and the magnitude of voltage of this signal is target voltage values.Threshold value setting module can be adjusted two upper lower threshold values of comparator, and target voltage values is in the threshold range of these two threshold value compositions.
S705: comparator is in the time that real work voltage is greater than first threshold, output terminal output first controls signal to the voltage cut-out pipe of urea nozzle, in the time that real work voltage is less than Second Threshold, output terminal output second controls signal to the voltage cut-out pipe of urea nozzle; Wherein, the first control signal control switch pipe turn-offs, the second control signal control switch pipe conducting.
Wherein, if real work voltage between first threshold and Second Threshold, comparator can keep current output.
It should be noted that, in the present embodiment, the not circumscribed of execution sequence of step S701 and step S702-S704, also circumscribed not of the execution sequence of step S704 and step S702-S703, can successively carry out, and also can carry out simultaneously.The execution the present embodiment that wherein can circulate, controls the operating current of urea nozzle in real time thereby realize.
The present embodiment can be in the current control system of arbitrary urea nozzle provided by the invention.For example, this current control system can comprise sampling module 101, controller 102, D/A converter module 103, threshold value setting module 104, comparator 105 and diagnostic module 501.Now the described method of the present embodiment can also comprise: the real work voltage that diagnostic module is exported according to the working state of the voltage cut-out pipe of urea nozzle and sampling module 101 judges whether described system breaks down.
In the present embodiment, described method can also comprise:
Controller is directly controlled the voltage cut-out pipe conducting of urea nozzle or is closed.For example, in the time that system need to be turn-offed urea nozzle, assign and turn-off order by MCU, shutoff voltage control switch pipe 106, the electric current continuous decrease of urea nozzle, finally reaches the function of shutoff.
In the present embodiment, in order further signal to be adjusted, described method can also comprise:
By the first voltage follower, the signal of comparator output is isolated and amplify after export the voltage cut-out pipe of urea nozzle to; And/or
By second voltage follower, the real work voltage of sampling module output is isolated and amplify after export the voltage cut-out pipe of urea nozzle to.
The above is only the preferred embodiment of the present invention; it should be pointed out that for those skilled in the art, under the premise without departing from the principles of the invention; can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.
Claims (10)
1. a current control system for urea nozzle, is characterized in that, described system comprises:
Sampling module, after the real work current conversion of described urea nozzle is real work voltage, exports the first input end of comparator to;
Controller, for the target current value of described urea nozzle is converted to target voltage values, exports described target voltage values to D/A converter module; In first period of wherein starting working in described urea nozzle, the target current value of described urea nozzle is peak current value, and after described the first period, the target current value of described urea nozzle is for maintaining current value;
D/A converter module, for described target voltage values is converted to after analogue signal, exports the second input end of described comparator to;
Threshold value setting module, is respectively first threshold and Second Threshold for the upper lower threshold value that described comparator is set; Wherein, described first threshold is greater than described target voltage values, and described Second Threshold is less than described target voltage values;
Comparator, for in the time that described real work voltage is greater than described first threshold, output terminal output first controls signal to the voltage cut-out pipe of described urea nozzle, in the time that described real work voltage is less than described Second Threshold, output terminal output second controls signal to the voltage cut-out pipe of described urea nozzle;
Wherein, switching tube turn-offs described in described the first control signal control, switching tube conducting described in described the second control signal control.
2. system according to claim 1, is characterized in that, described system also comprises: diagnostic module;
Described diagnostic module is for judging according to the real work voltage of the working state of described switching tube and the output of described sampling module whether described system breaks down.
3. system according to claim 1, is characterized in that, described system also comprises: the first voltage follower;
Described the first voltage follower is arranged between described comparator and described switching tube, for after the signal of described comparator output is isolated and amplifying, exports described switching tube to.
4. system according to claim 1, is characterized in that, described system also comprises: second voltage follower;
Described second voltage follower is arranged between described comparator and described sampling module, for after the real work voltage of described sampling module output is isolated and amplifying, exports described comparator to.
5. system according to claim 1, is characterized in that, described system also comprises: reference diode;
Described reference diode is arranged between described comparator and described switching tube, for the signal of described comparator output is carried out, after voltage stabilizing, exporting described switching tube to.
6. system according to claim 1, is characterized in that, described sampling module comprises sampling resistor and voltage acquisition module; The electric current that described sampling resistor flows through is the real work electric current of described urea nozzle;
Described voltage acquisition module is for gathering the voltage at described sampling resistor two ends, as extremely described comparator of described real work Voltage-output.
7. system according to claim 1, is characterized in that, described threshold value setting module comprises the first resistance and the second resistance;
Described the first resistance is arranged between described sampling module and the first input end of described comparator, and described the second resistance is arranged between the first input end and described output terminal of described comparator.
8. a current control method for urea nozzle, is characterized in that, described method comprises:
After sampling module is real work voltage by the real work current conversion of described urea nozzle, export the first input end of comparator to;
The target current value of described urea nozzle is converted to target voltage values by controller, exports described target voltage values to D/A converter module; In first period of wherein starting working in described urea nozzle, the target current value of described urea nozzle is peak current value, and after described the first period, the target current value of described urea nozzle is for maintaining current value;
D/A converter module is converted to described target voltage values after analogue signal, exports the second input end of described comparator to;
The upper lower threshold value that threshold value setting module arranges described comparator is first threshold and Second Threshold; Wherein, described first threshold is greater than described target voltage values, and described Second Threshold is less than described target voltage values;
Described comparator is in the time that described real work voltage is greater than described first threshold, output terminal output first controls signal to the voltage cut-out pipe of described urea nozzle, in the time that described real work voltage is less than described Second Threshold, output terminal output second controls signal to the voltage cut-out pipe of described urea nozzle;
Wherein, switching tube turn-offs described in described the first control signal control, switching tube conducting described in described the second control signal control.
9. method according to claim 8, is characterized in that, the current control system of urea nozzle comprises: described sampling module, described controller, described D/A converter module, described threshold value setting module, described comparator and diagnostic module;
Described method also comprises:
Described diagnostic module judges according to the real work voltage of the working state of described switching tube and the output of described sampling module whether described system breaks down.
10. method according to claim 8, is characterized in that, described method also comprises:
By the first voltage follower, the signal of described comparator output is isolated and amplify after export described switching tube to; And/or
By second voltage follower, the real work voltage of described sampling module output is isolated and amplify after export described comparator to.
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| CN106988836A (en) * | 2015-10-20 | 2017-07-28 | 博世株式会社 | The control device of reducing agent injection apparatus |
| JP2018204524A (en) * | 2017-06-02 | 2018-12-27 | 株式会社デンソー | Fuel injection control device |
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| CN103321727A (en) * | 2012-03-21 | 2013-09-25 | 联创汽车电子有限公司 | Catalyst jetting and controlling circuit of automobile off-gas treating system |
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| CN1953311A (en) * | 2005-10-17 | 2007-04-25 | 力博特公司 | A control method for load current and device |
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| US20120255282A1 (en) * | 2009-12-15 | 2012-10-11 | Bosch Corporation | Control device and control method for reduction agent injection valve |
| CN102182577A (en) * | 2011-01-30 | 2011-09-14 | 潍柴动力股份有限公司 | Engine electronic control unit |
| US20130229294A1 (en) * | 2012-03-05 | 2013-09-05 | Kabushiki Kaisha Toshiba | Analog-to-digital converter |
| CN103321727A (en) * | 2012-03-21 | 2013-09-25 | 联创汽车电子有限公司 | Catalyst jetting and controlling circuit of automobile off-gas treating system |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106988836A (en) * | 2015-10-20 | 2017-07-28 | 博世株式会社 | The control device of reducing agent injection apparatus |
| CN106988836B (en) * | 2015-10-20 | 2020-10-20 | 博世株式会社 | Control device for reducing agent injection device |
| JP2018204524A (en) * | 2017-06-02 | 2018-12-27 | 株式会社デンソー | Fuel injection control device |
| JP7095233B2 (en) | 2017-06-02 | 2022-07-05 | 株式会社デンソー | Fuel injection control device |
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|---|---|
| CN104005818B (en) | 2016-08-17 |
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