Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D31/00—Use of speed-sensing governors to control combustion engines, not otherwise provided for
  • F02D31/001—Electric control of rotation speed
  • F02D31/007—Electric control of rotation speed controlling fuel supply
  • F02D31/009—Electric control of rotation speed controlling fuel supply for maximum speed control

Definitions

• the invention relates to a method and a device for speed controller function monitoring, in particular in a thrust monitoring function of a diesel engine control.
• an overrun monitoring function can be activated as an error handling function if the actual rotational speed is above the setpoint rotational speed by more than a predetermined threshold value.
• a predetermined period of time say one second, including all other retarding functions, the injection is switched off, ie. the drive duration of the injectors has been brought to zero.
• the provided in the engine control speed controller work depending on the application, ie type of manufacturer of the motor vehicle or depending on the motor vehicle with different parameter sets that lead to different response times of the speed controller.
• the injection upon intervention of the thrust monitor, for each parameter set, the injection must be shut off within the predetermined period of time to avoid an unjustified thrust monitor replacement response.
• a check of each parameter set must be carried out again for each vehicle type or field of application of the internal combustion engine. The checking is carried out with the aid of suitable simulations, wherein in particular it is checked that the manipulated variable is within the predetermined period of time, ie one second, leads to a stop of the injection. This is expensive.
• a method for monitoring a function of a speed control of an internal combustion engine includes detecting a speed overshoot when an actual speed of the engine exceeds a desired speed by more than a predetermined threshold, and, when a speed over is detected, limiting a speed control variable to a time-out maximum speed.
• the maximum manipulated variable may depend on a predetermined period of time after which the manipulated variable must be set to 0.
• the gradient with which the maximum manipulated variable decreases over time is constant.
• the gradient can be determined from a maximum manipulated variable, which indicates a maximum permissible manipulated variable in normal operation, divided by the predetermined period of time.
• the gradient may be determined from the current maximum manipulated variable divided by the predetermined period of time.
• the maximum manipulated variable may decrease over time in accordance with a gradient profile.
• the manipulated variable of the rotational speed control can be limited to a temporally increasing maximum manipulated variable, wherein the maximum manipulated variable increases up to a maximum manipulated variable which indicates a maximum permissible manipulated variable in normal operation.
• the maximum control variable when the setpoint speed is undershot by the actual speed, can be set directly to the maximum control variable, wherein the maximum control variable indicates a maximum permissible control variable during normal operation.
• a motor control for operating an internal combustion engine is provided with a control unit for providing a manipulated variable as a function of a desired rotational speed and an actual rotational speed; and a limiting unit for detecting a speed exceeding when the actual speed of the internal combustion engine exceeds the target speed by more than a predetermined threshold, and for limiting a control variable of the speed control to a time-decreasing maximum control variable when a speed overshoot is detected.
• control unit may comprise a P-controller part and an I-controller part, wherein the limiting unit has a common one of the P-controller part and the I-controller part.
• the control unit may include a P-controller part and an I-controller part, wherein the limitation unit is coupled to the I-controller part such that the limitation unit updates an integration output value of an integrator of the I-regulator part when limiting with a limit integrator value in each control cycle.
• Fig. 1 is a block diagram of a speed controller for a motor controller according to a first embodiment of the invention
• FIG. 2 is a block diagram of a speed controller for a motor controller according to another embodiment of the invention
• FIG. and Fig. 3 is a timing diagram illustrating the timing of the maximum torque depending on the actual engine speed.
• an engine system 1 with an internal combustion engine 2 and a speed control is shown schematically.
• the speed control is performed as an example as a PI controller and delivers depending on a differential speed .DELTA. ⁇ a manipulated variable S eg in the form of a set torque or an amount of fuel to be injected.
• the speed control comprises a differential element 5 for calculating a rotational speed difference between a desired rotational speed ⁇ s o ii provided externally (eg according to a driver's desired torque in a motor vehicle) and an actual rotational speed ooi st determined in the internal combustion engine 2.
• the differential rotational speed ⁇ becomes a proportional element 6 (P controller part) and an integrator 7 8I controller part) of the controller.
• the proportional element 6 and the integration element 7 respectively provide partial manipulated variables Si and S 2 , which are added in a summing element 8 in order to generate the manipulated variable S.
• a limiting member 10 is provided to which the information about the rotational speed difference ⁇ is supplied and which is activated as soon as the rotational speed difference ⁇ is greater than a threshold value SW, which is fixed. If the threshold value SW is not exceeded, the manipulated variable S is provided unchanged to the internal combustion engine 2. However, if the differential speed ⁇ is above the threshold value SW, the manipulated variable S of the speed control is limited to a maximum torque M max .
• the limiting member 10 In order to ensure that the manipulated variable S, with which the internal combustion engine 2 is controlled, in such an activated case, ie when the differential rotational speed ⁇ is above the threshold, brought to 0 within a predetermined period of time, which is indicated by T A is, the maximum torque M max over time is reduced linearly or according to a predetermined gradient profile (see time Tl).
• a manipulated variable S which corresponds to a torque above the maximum torque M max , is limited to M max .
• the reduction of the maximum torque M max over time is continued until M max either indicates 0 Nm or the differential speed ⁇ falls below the threshold value (see time T2).
• the maximum torque M max is continuously increased again from the currently attained maximum torque M max over the time t in the direction of a predefined maximum value, which, however, is not exceeded . If during the increase of the maximum torque M max again ⁇ exceeds the threshold value (see time T3), starting from the now reached maximum torque M max , the maximum torque M max is reduced linearly or according to a gradient profile until either 0 Nm is reached or until ⁇ falls below the threshold again. If ⁇ is above the threshold value SW and the maximum torque M max is already 0 Nm (see period between T3 and T4), then M max is kept at 0 Nm and thus the manipulated variable S is limited to 0 Nm.
• the manipulated variable delivered to the engine 2 is zero, that is, no fuel is injected into the engine 2.
• the maximum permissible torque M max is again increased according to a gradient.
• the gradient with which the maximum torque M max is reduced, as soon as the threshold value SW is exceeded by the differential rotational speed ⁇ , is determined by the time period in which the manipulated variable must be brought to zero, if the differential rotational speed ⁇ exceeds the threshold SW ü-.
• This time period T A can be, for example, one second.
• the gradient of the decrease in the maximum torque M max results, for example, from a predetermined maximum torque (corresponds to a maximum torque permissible in normal operation, shown as a solid thin horizontal line in the upper diagram of FIG. 3) divided by the predetermined time duration, so that at a prevailing maximum torque, the limit value is 0 Nm at the latest after the predetermined time period T A.
• the maximum torque M max can also be used for the gradient calculation.
• the amount of the gradient in the case of increasing the maximum torque M max as soon as the threshold value is again undershot by the differential speed is preferably selected to be the same as the gradient of the falling ramp of the maximum torque curve M max in the aforementioned case.
• the maximum torque M max is immediately set to the maximum torque. A torque jump does not arise because the manipulated variable components Si and S 2 are significantly below the maximum value.
• the limit value is usually stored in an existing EEPROM upon intervention of the limitation in a static data memory. In this way, it can be determined in a test whether the limitation had to intervene or whether the control parameters allow sufficiently fast speed control to meet the requirement for the manipulated variable reduction time.
• Fig. 2 shows a further embodiment of an engine system according to the invention.
• the same elements or elements of the same function are provided with the same reference numerals.
• the embodiment of FIG. 2 differs from the embodiment of FIG. 1 in that the limiting unit is not provided in the adjusting path between the summing member 8 and the internal combustion engine 2, but on the integrating member 7.
• the limiting unit 11 of the embodiment of FIG. like the limiting unit 10 of the embodiment of FIG. 1, receives the differential rotational speed ⁇
• Threshold SW and the predetermined period of time T A detects on the basis of an exceeding of the threshold value SW by the differential speed ⁇ , that the maximum torque M max should be limited.
• the value of the maximum torque M max which determines the limiting value, is determined as previously described in the example of the embodiment of FIG. 1.
• the partial manipulated variable Si provided by the proportional element 6 is subtracted, thereby determining a limit integration value with which before each integration cycle the integration output value (integration value from which at integration in one cycle is assumed) of the integration member 7 is updated. That is, when the present integrator value (integrator value after integration) is larger than the limit integration value provided by the constraint unit 11, the integration output value is updated to the limit integration value provided by the constraint unit 11. If the integration value 7 in the integration element 7 is smaller than the limit integration value provided by the limitation unit 11, no update takes place.
• the inventive method has the advantage that it can be ensured that the manipulated variable of the speed control reaches zero in any case after the predetermined period of time.
• T A a time period within which the maximum controller output torque (manipulated variable) is driven linearly from the maximum torque to the neutral value (manipulated variable 0) if the rotational speed is too high.
• the internal thrust monitoring does not respond incorrectly, which is checked for unjustified injection after a certain period of time, such as one second, thrust.
• a user can not unintentionally trigger such a fault, so that the controller application can be completely left to the user and does not have to be additionally checked with regard to the thrust monitoring.
• a PI D controller may be provided, but the differential component of the manipulated variable should not be acted upon by the limiting element and therefore should be added to the possibly already limited manipulated variable of the P and I component of the manipulated variable.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Combined Controls Of Internal Combustion Engines (AREA)
• Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
• Control Of Electric Motors In General (AREA)

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Publications (1)

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Citations (5)

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• 2007
  • 2007-07-11 DE DE102007032214A patent/DE102007032214A1/de not_active Withdrawn
• 2008
  • 2008-06-09 RU RU2010104399/06A patent/RU2461726C2/ru not_active IP Right Cessation
  • 2008-06-09 EP EP08774056A patent/EP2165062B1/de active Active
  • 2008-06-09 WO PCT/EP2008/057152 patent/WO2009007186A1/de active Application Filing
  • 2008-06-09 DE DE502008001667T patent/DE502008001667D1/de active Active
  • 2008-06-09 ES ES08774056T patent/ES2352097T3/es active Active
  • 2008-06-09 AT AT08774056T patent/ATE486204T1/de active
  • 2008-06-09 CN CN2008800240008A patent/CN101688485B/zh active Active

Patent Citations (5)

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