Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
  • F02P19/00—Incandescent ignition, e.g. during starting of internal combustion engines; Combination of incandescent and spark ignition
  • F02P19/02—Incandescent ignition, e.g. during starting of internal combustion engines; Combination of incandescent and spark ignition electric, e.g. layout of circuits of apparatus having glowing plugs
  • F02P19/025—Incandescent ignition, e.g. during starting of internal combustion engines; Combination of incandescent and spark ignition electric, e.g. layout of circuits of apparatus having glowing plugs with means for determining glow plug temperature or glow plug resistance
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
  • F02P19/00—Incandescent ignition, e.g. during starting of internal combustion engines; Combination of incandescent and spark ignition
  • F02P19/02—Incandescent ignition, e.g. during starting of internal combustion engines; Combination of incandescent and spark ignition electric, e.g. layout of circuits of apparatus having glowing plugs
  • F02P19/021—Incandescent ignition, e.g. during starting of internal combustion engines; Combination of incandescent and spark ignition electric, e.g. layout of circuits of apparatus having glowing plugs characterised by power delivery controls
  • F02P19/022—Incandescent ignition, e.g. during starting of internal combustion engines; Combination of incandescent and spark ignition electric, e.g. layout of circuits of apparatus having glowing plugs characterised by power delivery controls using intermittent current supply

Definitions

• the present invention relates to a method and system for controlling a glow plug, with a low-voltage power supply, of an air / fuel mixture of a diesel engine.
• a diesel engine requires a certain temperature so that the combustion reaction of the air / fuel mixture can take place.
• the engine is cold, the only compression of the air / fuel mixture does not make it possible to reach the ignition temperature, and it is then necessary to preheat the air / fuel mixture by means of glow plugs.
• the ignition temperature is the temperature at which the combustion reaction of the air / fuel mixture becomes spontaneous.
• High-voltage glow plug means a spark plug which is supplied at a nominal voltage of 1 1 volts, and by low-voltage glow plug, a spark plug which is supplied at a nominal voltage of less than 1 volts (4.5 volts). for example).
• the high-voltage glow plugs take longer than the low-voltage glow plugs to reach the ignition temperature of the air / fuel mixture, because during the so-called BOOST phase of the preheating, low-voltage spark plugs of 4.5 Nominal volts will be supplied with overvoltage at 11 volts. From where a very fast rise in temperature. That is why the duration of the BOOST (overvoltage supply) must be perfectly controlled to avoid overheating leading to the deterioration of the candles.
• BOOST overvoltage supply
• a low-voltage glow plug can not support, without risk of damage, two intensive heating phases too close together.
• An object of the invention is to provide an improved method and system for controlling a low-voltage, low-cost glow plug.
• a method of controlling a glow plug, low voltage power supply, an air / fuel mixture of diesel engine Said candle is supplied with electrical voltage by pulses having a predetermined amplitude and duration, the amplitude being less than a maximum amplitude.
• the amplitudes and durations of the electric voltage pulses supplying said spark plug are managed according to first parameters comprising preceding pulse durations and durations separating previous successive pulses.
• first parameters comprising preceding pulse durations and durations separating previous successive pulses.
• the previous pulses delivered to the glow plugs are taken into account, which makes it possible to avoid uses in which these would be deteriorated. Also, it avoids the use of a sensor for measuring the temperature provided by the glow plugs to the air / fuel mixture.
• said first parameters comprise engine operating parameters, and / or an available electrical voltage from which the electrical supply voltage of said spark plug is provided, and / or information representative of the activation / deactivation of the spark plug. the engine alternator, and / or a desired temperature to be provided by said spark plug.
• said operating parameters of the engine comprise the temperature of the heat transfer fluid for regulating the engine temperature, and / or the atmospheric pressure, and / or the temperature of the fresh intake air of the engine. and / or the speed of rotation of the engine. Such data are generally already available because necessary for the operation of other devices on board the vehicle.
• said pulse management comprises a preheating phase that can be implemented before starting the engine when the alternator is activated.
• said pulse management comprises a heating phase that can be implemented during a motor start.
• said pulse management comprises a post-heating phase that can be implemented following a start of the motor.
• said pulse management includes a heating off phase.
• said pulse management comprises an additional heating phase that can be implemented during an established operation of the motor.
• said preheating phase comprises a rapid preheating step implemented by one of said pulses of amplitude equal to said maximum amplitude.
• said preheating phase comprises a pre-heat pre-heating step implemented by one of said pulses, of a predetermined amplitude less than said maximum amplitude.
• the spark plug manufacturing dispersion is taken into account by mapping the duration of the pulse of said fast preheat step, when the desired temperature to be supplied by the spark plug is greater than a threshold temperature, and calculating the duration of the pulse of said fast preheating step as a function of the square of the ratio of a reference electric voltage and the available electrical voltage from which the supply voltage of said spark plug is supplied, and a reference time to reach the desired temperature to be provided by the candle under said reference voltage at a reference temperature.
• the manufacturing dispersion of the spark plug is taken into account by progressively increasing the amplitude of said pulse of the heating phase when the engine is started.
• the amplitude of said pulse is increased when, at startup, the rotational speed of the motor does not reach a first predetermined rotational speed in a first predetermined time.
• said gradual increase in pulse amplitude is a function of said amplitude of the pulse, and is less than a maximum increase.
• the time wear of said spark plug is taken into account, by adapting the amplitudes of said pulses over time, by using a corrective factor depending on the difference between a measured rotational speed of the engine and a rotational speed of the engine. reference for a reference engine operating point.
• the temperature supplied by said spark plug is evaluated and the magnitude of said predetermined pulses is adjusted using a closed loop integral proportional regulator.
• a low voltage electrical power supply glow plug control system a diesel engine air / fuel mixture, including controlled voltage supply means for the electric power supply.
• said candle adapted to deliver pulses having a predetermined amplitude and duration, the amplitude being less than a maximum amplitude.
• the system further comprises an electronic control unit provided with means for managing said supply means, said electronic control unit being able to remain energized for a predetermined period of time after a motor stop.
• Said management means comprise means for determining the value of first parameters comprising preceding pulse durations and durations separating previous successive pulses.
• FIG. 1 shows an embodiment of a system according to one aspect of the invention
• FIG. 2 is a block diagram of a method according to one aspect of the invention
• FIG. 3 illustrates an example of operation of a method according to one aspect of the invention
• Figures 4, 5 and 6 illustrate the consideration of the manufacturing dispersion of the glow plugs according to one aspect of the invention
• FIG. 7 illustrates taking into account the candle manufacturing dispersion in one embodiment of a method according to one aspect of the invention
• FIG. 8 illustrates the taking into account of the temporal wear of the candles in a method according to an embodiment of the invention.
• a diesel engine 1 is provided with four glow plugs 2 with low-voltage power supply.
• An alternator 3 is connected to the diesel engine 1 via a connection 3a, and an electric battery 4 supplies the system with electrical voltage via connections 4a.
• a controlled voltage supply module 5 of the glow plugs 2 of the diesel engine 1 delivers pulses, having a predetermined amplitude and duration, to the glow plugs 2.
• An electronic control unit 6 comprises a management module 7 of the controlled voltage supply module 5 of the candles 2.
• the controlled module 5 may be a module belonging to the electronic control unit 6.
• Determining means for example sensors or calculation modules, make it possible to determine operating parameters of the motor 1 and to transmit them via a connection 8 to the electronic control unit 6.
• engine operating parameters comprise the temperature T fC regulating coolant engine temperature 1, and / or the atmospheric pressure P tm, and / or the temperature T air from the fresh air inlet of the motor 1, and / or rotational speed
• the electronic control unit 6 furthermore receives, as input parameters, the available electric voltage Ubat supplied by the electric supply battery 4, a parameter P os _acc representative of the position of the accelerator pedal, and a piece of information I a / d_ait representative of the activation / deactivation of the alternator 3 of the motor 1, respectively by connections 9, 10 and 11.
• the electronic control unit 6 receives as input a temperature T BOU gie_des desired that the glow plugs 2 are provided.
• the temperature Tb OR gie_des to be provided by the glow plugs 2 is provided by a map 12 by means of a connection 12a, from parameters transmitted to the electronic control unit 6.
• the management module 7 comprises a determination module 13 for the value of first parameters comprising previous pulse durations and durations separating pulses. previous successive delivered by the controlled module 5 to the glow plugs 2.
• a phase PO in which the motor is stopped, and the electronic control unit 6 is energized or not is represented.
• the system is in this PO phase following a power supply voltage failure of the alternator 3, for example when the ignition is turned off by means of the ignition key.
• a predetermined period generally of the order of ten minutes, the electronic control unit 6 remains energized, and beyond this predetermined time, the electronic control unit 6 is no longer energized.
• a preheating phase P1 makes it possible to implement the heating of the air / fuel mixture by the glow plugs 2 before starting the engine 1.
• a heating phase P2 during a starting of the engine makes it possible to implement the heating of the air mixture / fuel during engine start 1.
• a post-heating phase P3 following a start of the engine 1 makes it possible to implement the heating of the air / fuel mixture by the glow plugs 2 following a start of the engine 1.
• a heating stop phase P4 makes it possible to stop the heating of the air / fuel mixture by the glow plugs 2.
• an additional heating phase P5 makes it possible to implement heating of the air / fuel mixture, when this is necessary, in operation of the engine 1 in the steady state. This may be necessary, for example when taxiing at altitude, where the decrease in atmospheric pressure (less air) affects the performance of the engine (degradation of combustion).
• the preheating phase P1 before starting the engine 1 comprises a step Mi I waiting for heating, a step M12 fast pre-preheating, a step M 13 rapid preheating, a step M 14 of maintaining heating, and a step M15 shutdown heating.
• a plurality of transitions between the stages of the preheating phase P1 before starting the engine 1 are possible.
• the amplitude of the electrical voltage supply pulse of the candles is zero.
• the rapid preheating step M12 makes it possible, for reasons of electrical consumption, to supply the glow plugs 2 with PWM-PRE-BOOST amplitudes strictly less than 100% for a period of time TEMPS_PRE_BOOST.
• [U bat The duration TEMPS_PRE_BOOST of the fast preheating state M12 depends on previous pulse durations and periods of time between previous successive pulses, the temperature Tf C of the heat transfer fluid for regulating the temperature of the engine 1, the air temperature T. the fresh air from the engine 1, the available electric voltage Ubat supplied by the electric battery 4, and the atmospheric pressure P a tm-
• the fast preheating step M 13 is implemented by means of a supply pulse of amplitude equal to the maximum amplitude PWM_MAX, or in other words, expressed as a percentage of the maximum amplitude PWM_MAX, a amplitude
• PWM_BOOST 100% for a time TIME_BOOST.
• the electric voltage Ubat supplied by the battery is greater than the threshold voltage U s , it is possible to limit the PWM supply amplitude of the candles 2.
• the heating maintaining step M 14 makes it possible to maintain the desired temperature Tb OR gie_des, and reached at the end of the last step M13 carried out with rapid preheating.
• the desired temperature Tb OR gie_des is maintained for a duration TEMPS_MAINTIEN_CHAUFFAGE which depends on the temperature Tf C of the coolant, the desired temperature
• the amplitude PWM_MAINTIEN_CHAUFFAGE depends on the voltage Ubat provided by the battery 4 and the desired temperature Tb OR gie_des to maintain.
• the temperature is dependent on the temperature Tf C of the coolant, the atmospheric pressure
• the step M15 of stopping the maintenance of heating corresponds to a cut of the heating just before the effective launching of the phase P2 of heating during a starting of the motor 1.
• the amplitude PWM_ARRET_MAINTIEN_CHAUFFAGE 0% (cutout heating) .
• the amplitude PWM_CHAUFFAGE_DEMARRAGE depends on the voltage Ubat provided by the battery 4 and the temperature Tbou g ies_des desired.
• the desired start temperature depends on the temperature Tf c of the coolant, the atmospheric pressure P a tm and the temperature T air of the intake air.
• M31 postheating step comprising two stages M31 and M31b of postheating first and second post-heating, and a step M32 stop postheating.
• the latter can not be maintained at an elevated temperature for a too long duration.
• a candle 2 can withstand a temperature of 1000 ° C for three minutes of post-heating, it may not be able to withstand 1100 ° C for more than 15 seconds only.
• Two sub-steps M31 and post-heating M31b are therefore used.
• a first sub-step M31 has post-heating time and temperature adjustable according to the initial conditions of the engine, that is to say, before starting.
• a second sub-step M31b post-heating of varying duration and temperature depending on the operating conditions of the motor 1.
• the temperature TEMPERATURE_POST_CHAUFFAGE_1 depends on the temperature Tf C of the heat transfer fluid, the temperature obtained at the end of the rapid preheating step M 13, the atmospheric pressure P a tm and the temperature T air of the intake air of the motor 1.
• the TEMPERATURE_POST_CHAUFFAGE_2 temperature depends on the temperature Tf C of the coolant, temperature TEMPERATURE_POST_HAUFFAGE_1, the atmospheric pressure P atm , the temperature T air intake air, the speed V mo t of rotation of the engine, and motor torque C mo t-
• PWM_POST_CHAUFFAGE_1 and PWM_POST_CHAUFFAGE_2 depend on the voltage Ub at supplied by the battery 4 and the respective post-heating temperatures TEMPERATURE_POST_
• the post - heating stop step M32 corresponds to a cut of the heating provided by the glow plugs 2, the amplitude of the control pulses is zero or in other words, expressed as a percentage of the maximum amplitude,
• the auxiliary heating phase P5 comprises an intermediate heating step M51, and an intermediate heating stopping step M52.
• the assistance of the glow plugs 2 is requested, for example when the combustion is degraded due to taxiing at altitude, or for any special need for heat in the combustion chamber of the engine.
• the intermediate heating temperature, to be supplied by the glow plugs 2 depends on the temperature T fc of the coolant, the atmospheric pressure P a tm, the air intake temperature T air , the speed V mo t rotation of the engine 1, and the engine torque C mo t- The amplitude
• PWM_CHAUFFAGE_INTERMÉDIAIRE depends on the voltage Ubat provided by the battery 4 and the intermediate heating temperature Tb OR gie_des desired.
• Transition Management U uses time counters.
• the time counters considered are as follows.
• a time counter COMPTEUR_POWER_LATCH is initialized to zero at each entry in the phase PO, when the voltage supply of the alternator 3 is cut off, for example by a contact key.
• HEATING is initialized to zero at each input, by the transitions t 2 or to 2 , in the step M 14 for maintaining heating.
• a time counter COUNTER_FIRE_MAINTIEN_ HEATING is initialized to zero at each entry in the step M15 of stopping the maintenance of heating, by the transitions to3 or t 3 , and at each exit of the preheating phase P1 through the transition t 4 .
• a time counter COUNTER_POST_HEATING is initialized to zero at each entry in the step M31 of post-heating, by the transition t 6 .
• a time counter COUNTER_POST_HEATING_1 is initialized to zero at each entry in sub-step M31a of first post-heating, by the transition t 6 .
• a time counter COUNTER_POST_HEATING_2 is initialized to zero at each entry in sub-step M31b of second post-heating, by the transition t 6 and at each return in sub-step M31b of second post-heating by the transition tio-
• a time counter COMPTEUR_BOOST includes the steps M12 of preheating and M13 fast preheating. Its incrementation starts with the pre-preheating step M12 and continues in the fast preheating step M 13. The counting or timing ends at the exit of the step M 13 rapid preheating.
• the COUNTER_BOOST counter always returns from the last value kept in memory until it has been initialized to zero.
• the time counter COMPTEUR_BOOST is initialized to zero each time the sum of the time counters COMPTEUR_POWER_LATCH + COUNTER_ARRET_MAINTIEN_ HEATING exceeds a threshold time t seU ii_ref necessary for the cooling of the candle, generally of the order of 1 to 4 minutes.
• An INTERMEDIATE HEAT COUNTER time counter is initialized to zero at each input in the intermediate heating step M51 by the transmission t 14 .
• INTERMEDIATE is initialized to zero at each entry in step M52 stopping intermediate heating, by the transition tis.
• TEMPS_PRE_BOOST + TEMPS_BOOST which is a first function Fl of the temperature T fc of the heat transfer fluid, atmospheric pressure P tm, the air temperature T of the intake air, and the voltage Ubat of the battery.
• time counter TEMPS_PRE_BOOST is a second function F2 of the temperature T fc of the coolant, the pressure of the atmospheric pressure P a tm, the temperature T air of the intake air, and the voltage Ubat provided by the battery 4
• time counter TEMPS_BOOST is a third function F3 of the temperature T fc of the coolant, the atmospheric pressure P a t m , the temperature T air of the intake air, and the Ubat voltage supplied by the battery 4.
• COUNTER_HOT_MAIN_TIME is less than the time threshold t seU ii_ref, and that TEMPS_PRE_BOOST is less than
• COUNTER_HOT_CURRENT_NOTE lower than t se ii ref And that COUNTER_BOOST is greater than the sum
• the minimum threshold time t u ii_mini corresponds to the minimum delay that must be expected since the end of a rapid preheating step M 13, to be able to restart a rapid preheating step
• the transition to3 is performed when the temperature Tf C of the coolant, the atmospheric pressure P atm and the temperature T air intake air, are such that the preheating phase Pl is unnecessary.
• the transition ti is a transition from the rapid preheating stage M 12 to the rapid preheating stage M 13.
• the transition t 2 represents the transition from the preheating step M13 to the heating holding step M14.
• transition t 3 represents the stopping of the preheating, to preserve the state of the glow plugs 2, if the start has not begun beyond a maximum duration
• COUNTER_MAINTIEN_CHAUFFAGE is greater than TIME_MAINTIEN_CHAUFFAGE_MAX, the transition t 3 is carried out, and the maintenance of the heating is stopped.
• transition t 4 if the engine is in the start-up phase and the temperature of the engine 1 is lower than a maximum threshold temperature T se u ii_max, or if the temperature of the engine 1 is lower than a maximum threshold temperature T u se ii_max and the speed V mo t of rotation of the engine 1 is greater than a minimum threshold rotation speed TV seU ii_mini, the transition t 4 is performed, and the phase P2 of heating during a start of the engine 1 is carried out.
• the transition ts is performed when during the heating phase P2 during a start of the engine 1, the engine 1 has stalled, and the step M15 of stopping the maintenance of the heating is performed.
• transition t 6 is carried out when the engine 1 is considered as autonomous, after having started, and the post-heating phase P3 is then activated.
• the transition t 7 is performed at the end of the first sub-step M31 a of post-heating.
• the duration TIME_POST_CHAUFFAGE_1 of the first sub-step M31 a of post-heating is a function F 4 of the temperature Tf C of the coolant, of the atmospheric pressure P a tm, of the temperature T air of the air of admission, desired at the end of the step M 13 rapid preheating.
• step M31a of first post-heating is stopped, to go to step M31b of second post- heater.
• the transition tg causes the stopping of the post - heating step M31, either because the duration TIME_POST_CHAUFFAGE_2 of the second substep M31b of post - heating has elapsed, or because the speed of rotation V rot and the torque C word of the engine are too high.
• the duration TEMPS_POST_CHAUFFAGE_2 of the second sub-step M31b of post-heating is a function F 5 of the temperature Tf C of the coolant, of the atmospheric pressure P a t m , of the temperature T air intake air, and the temperature assumed reached at the end of the sub-step M31 a of first post-heating.
• transition tio makes it possible to reactivate sub-step M31b of second post-heating as long as the maximum post-heating time allowed DUREE_MAX_POST_CHAUFFAGE has not elapsed.
• the transition t ⁇ is carried out, and the step M32 of the post-heating stop is activated. .
• the transition t 12 is carried out if the alternator is undervoltage (for example by putting the contact by the ignition key), and that the engine stalled.
• the step M15 for stopping the heating hold is reactivated.
• transition t 13 makes it possible to definitively stop the post-heating phase P3. If COUNTER_POST_HEATING is greater than
• the transition t 13 is carried out, and phase P3 of post-heating is stopped definitively.
• the phase P4 heating stop is activated.
• Transition t 14 is performed if the temperature of engine water is lower than the temperature T Seui i min minimum threshold, the C engine torque mo t is less than the minimum engine torque C min, the atmospheric pressure P tm is below a minimum threshold pressure P m in, and that the voltage Ubat supplied by the battery 4 is lower than a minimum threshold voltage voltage V min .
• the transition t 14 can also be carried out through a request for assistance to the alternator to meet any particular need of thermal in the combustion chamber of the engine.
• the intermediate heating step M51 which is activated.
• the tis transition is used to stop the intermediate heating beyond a predetermined TIME - WARM TIME, depending on the operating conditions of the motor 1.
• TIME_INTERNAL HEATING is greater than TIME_INTERNAL HEATING, the transition t 15 is performed, and the step M52 of intermediate heating stop is activated.
• the transition t 16 is carried out if the temperature of the air / fuel mixture is higher than the minimum threshold temperature
• COUNTER_HITCH_INTERNAL_HIDING is greater than a minimum threshold DUREE_HAUFFAGE_INTERMEDIAIRE_MIN
• the heating is then stopped.
• Figure 3 illustrates an example of operation according to one aspect of the invention.
• the rapid pre-preheating step M 12 starts with a supply of the candles having an amplitude of
• the step M 13 of fast preheating is activated, with a supply of candles 2 of maximum amplitude PWM_MAX, during a duration TEMPS_BOOST.
• the temperature of the air / fuel mixture of the engine increased significantly during the rapid preheating step M 13, to reach T boost .
• the heating holding step M 14 is activated, in order to maintain the temperature of the spark plugs 2 or of the air / fuel mixture at the Tboost temperature.
• the amplitude of the supply of the glow plugs 2 is PWM_MAINTIEN_CHAUFFAGE% of PWM_MAX, until moment i 4 which starts phase P2 of starting of the engine 1.
• the amplitude of the supply of the spark plugs is PWM_CHAUFFAGE_DEMARRAGE% of PWM_MAX, up to a time is of beginning of the step M31 a of first post - heating following the starting of the motor 1.
• step M31 the supply of candles has an amplitude equal to PWM_POST_CHAUFFAGE1_A% of PWM_MAX.
• the second post-heating step M31b is activated, with a power supply of amplitude.
• the first post-heating step M31 is reactivated, with an amplitude of the power of the glow plugs 2 equal to PWM_POST_CHAUFFAGE1_B% of PWM_MAX.
• the temperature of the air / fuel mixture is rapidly brought to a level allowing a start of the engine 1, and maintain such a temperature after starting the engine 1.
• One difficulty lies in the calibration of the duration of the step III 3 of rapid preheating taking into account the manufacturing dispersions of the glow plugs 2.
• the manufacturing dispersions can be important if the temperature required at the end of step M 13 rapid preheating is greater than a threshold temperature Ts.
• the duration TEMPS_BOOST of the fast preheating step M13 is determined from a map comprising, as input parameters, the temperature Tf C of the coolant, the atmospheric pressure P a tm, the temperature
• the duration TIME_BOOST of the fast preheating step M13 is governed by the equation:
• TEMPS_BOOST is the duration of the fast preheating step M13
• Ubat is the voltage supplied by the battery.
• TIME_REF is a reference time to reach the desired temperature of the candle under a reference voltage of the battery 4, and at an ambient temperature of 20 ° C.
• Ubat_ref is the reference voltage of the battery.
• FIG. 4 illustrates the manufacturing dispersion characteristics of the candles 2. It appears that the desired temperature at the end of the rapid preheating step M13 may not be guaranteed with mini candles providing a minimum temperature in the temperature range due to manufacturing dispersion. A high risk of bad or no start then exists.
• the PWM amplitude of the voltage supply applied to the spark plugs is progressively increased, in the event of detection of a bad start, or of a non-starting.
• the spark plugs 2 are supposed to be energized at steady state, with a power PWM amplitude of less than 100% (as illustrated in FIG.
• any controlled increase in the supply PWM amplitude or electrical voltage applied to the spark plugs 2 does not cause excessive overheating. Therefore, if in the start-up phase (step 20), the speed of rotation V word of the motor 1 does not reach the minimum rotation speed V min in a given time td_min (step 21), the amplitude PWM is corrected, as explained in Figure 7, in order to gradually increase the temperature of the candle. A predetermined correction p, expressed as a percentage, depending on the value of the current PWM amplitude, is applied (step 22).
• Xi can not exceed a predetermined maximum value X ma ⁇ (steps 24 and 26), in order to guarantee the protection of the candles 2.
• the last correction Xi applied to the supply PWM amplitude before the motor 1 is recognized as autonomous, is stored in memory (steps 27). It is directly used at the next iteration (step 29). The adaptation ends as soon as the engine 1 becomes autonomous
• step 28 because the process only concerns the PWM amplitude at startup.
• this learning makes it possible to ensure a start with mini candles having a rapid preheat Tboost temperature much lower than that obtained with nominal candles.
• TEMPS_BOOST rapid preheating can be stalled on a maximum candle, in order to allow to limit the rise in temperature or overheating of the candles maxi during the application of the process. If necessary, learning can be done on several starts.
• the amplitude PWM applied to the candles 2 over time is adapted to the behavior changes of the candles 2.
• the speed V mo t of rotation of the engine is analyzed under operating conditions of the engine 1 at idle (steps 30 and 31).
• An analysis can be performed post-heating, or intermediate heating.
• a transition condition for intermediate heating may be a learning request.
• the speed V mo of rotation of the motor is provided by a speed sensor of the motor 1.
• the speed V word can be evaluated on average over one or more cycles of two engine revolutions when the required operating conditions of the engine 1 are filled
• the average reference speed V ref is for example established when the engine is new.
• the amplitude PWM is corrected when the difference ⁇ V between the measured average speed V moy and the reference speed V ref exceeds a minimum threshold ⁇ V min .
• the adaptation takes place as long as the required conditions are fulfilled and as long as the difference in absolute value remains greater than the predetermined threshold ⁇ V min (steps 36 and 37).
• step 38 If the deviation is positive (step 38), an attempt is made to increase the PWM amplitudes (steps 39 and 40).
• step 38 If, on the contrary, the deviation is negative (step 38), an attempt is made to reduce the PWM amplitudes (steps 41 and 40).
• a correction p expressed as a percentage, depending on the value of the current PWM amplitude, is applied.
• Xi can not exceed a predetermined maximum value X ma ((steps 42 and 43), in order to guarantee the protection of the glow plugs 2.
• F_COR 1 + Xi is applied to the predetermined PWMs during the heating of the candles (step 44).
• the management of the controlled amplitude of the power supply voltage supplied to the spark plugs can be adapted automatically by means of a corrector or regulator PI (Proportional Integral).
• PI Proportional Integral
• Either the spark plugs 2 and / or the control module 5 are equipped with a device that makes it possible to directly measure the spark plug temperature, or the control module 5 is equipped with a device for measuring or estimating the electric voltage. U and the electric current I consumed by the heating element of the candle.
• the U / I ratio makes it possible to deduce the instantaneous resistance of the heating element, and at this instantaneous resistance value corresponds a temperature value of the spark plug or the air / fuel mixture.
• the determination of a temperature setpoint for each heating step or phase instead of a control PWM amplitude is predetermined as a function of the engine operating conditions (temperature Tf C of the coolant, temperature of the intake air, atmospheric pressure P a tm, electric voltage Ubat, supplied by the battery, motor speed V mo t of rotation, and engine torque C word ). It is continuously or recurrently compared with the information representative of the temperature of the candle returned to the electronic control unit 6. According to the temperature difference ⁇ T between the reference temperature representative of the actual temperature, the regulator PI automatically regulates the control amplitude PWM in order to maintain the temperature of the candle 2 substantially equal to the set temperature.

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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)
• Electric Propulsion And Braking For Vehicles (AREA)
• Ignition Installations For Internal Combustion Engines (AREA)

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