JP2008138582A - Temperature control device of heat generation means - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem where it is difficult to accurately control the temperature of a globe plug 24 projecting on a combustion chamber 20 of a diesel engine 10 by feedforward control. <P>SOLUTION: A cylinder block 16 of the diesel engine 10 is provided with a water temperature sensor 30. In an ECU 40, cooling water temperature THW1 detected by the water temperature sensor 30 is stored in a permanent memory holding memory 42 such as an EEPROM with a turning-off operation of an ignition switch IG. When temperature control of the globe plugs 24 is executed by turning on an ignition switch IG again, electric energy supplied to the globe plugs 24 is set based on variation of the current cooling water temperature THW2 with respect to the above cooling water temperature THW1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a temperature control device for a heat generating means for performing an energization operation on the heat generating means in order to feedforward control the temperature of the heat generating means protruding into a combustion chamber of an internal combustion engine.

  As this type of temperature control device, for example, a predetermined power amount (rated power) for controlling the temperature of a glow plug as a heating element protruding into a combustion chamber of a diesel engine to a target temperature is adapted in advance. It is well known that the temperature of the glow plug is controlled to a target temperature by an energization operation of electric power. Furthermore, it is also known that when starting the temperature control of the glow plug, an energization operation with an electric energy (initial electric energy) larger than the predetermined electric energy is performed in order to quickly raise the temperature of the glow plug to the target temperature. Yes. The initial power amount is adapted to an amount appropriate for raising the temperature of the glow plug to the target temperature.

  By the way, the controllability of the temperature of the glow plug when restarting the diesel engine depends on the initial value of the temperature of the glow plug. That is, for example, when the time from the start to the restart of the diesel engine is excessively short, there is a possibility that the temperature of the glow plug has not yet sufficiently decreased. In this case, if the initial electric energy is used when the diesel engine is restarted, the temperature of the glow plug may rise significantly above the target temperature.

Therefore, conventionally, for example, as seen in Patent Document 1 below, it has also been proposed to maintain the temperature control device on for a period during which the temperature of the glow plug is assumed to be sufficiently reduced when the diesel engine is stopped. . As a result, when the elapsed time from the stop to restart of the diesel engine is excessively short, the temperature control device can reduce the initial electric energy by grasping that the elapsed time is short, and thus the glow plug High controllability of temperature can be maintained.
JP 2004-108189 A

  However, it takes a long time for the temperature of the glow plug that has actually increased to sufficiently decrease. For this reason, in the said control apparatus, there exists a possibility that the ON time of the control apparatus after the stop of a diesel engine may become excessively long, and there exists a possibility that the power consumption of a battery may increase by extension.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to more appropriately perform an energization operation to the heat generating means in order to feedforward control the temperature of the heat generating means protruding into the combustion chamber of the internal combustion engine. It is an object of the present invention to provide a temperature control device for a heat generating means.

  Hereinafter, means for solving the above-described problems and the operation and effects thereof will be described.

  According to the first aspect of the present invention, the energization by the feedforward control is performed based on the amount of change in the temperature having a correlation with the operation history of the internal combustion engine from the stop of the temperature control device to the start of the temperature control of the heating means. A variable means for variably setting the operation mode is provided.

  The temperature change of the heat generating means during the period from when the temperature control apparatus is stopped to when the temperature control apparatus is started this time and the temperature control of the heat generating means is started depends on the length of the same period. On the other hand, due to the temperature rising during operation of the internal combustion engine, there are temperature parameters having a correlation with the operation history, such as the cooling water temperature and exhaust temperature of the internal combustion engine. The amount of change of the temperature parameter in the period has a correlation with the length of the period. In the above invention, attention is paid to the fact that the change amount of the temperature parameter is a parameter having a correlation with the period. That is, according to this property, the amount of change in the temperature parameter is also correlated with the amount of decrease in the temperature of the heat generating means. Therefore, by variably setting the energization operation mode based on the change amount of the temperature parameter, it is possible to perform an energization operation appropriate for the initial value of the temperature of the heat generating means, and to control the target temperature with high accuracy.

  According to a second aspect of the present invention, in the first aspect of the invention, the variable means increases the amount of power supplied at the start of the temperature control as the amount of change increases.

  The larger the temperature parameter change amount, the longer the period from the stop of the temperature control device to the start of the temperature control, so the temperature of the heating means is also considered to decrease. In this regard, in the above invention, the temperature of the heat generating means can be quickly controlled to the target temperature regardless of the length of the period by increasing the power supply amount as the change amount of the temperature parameter increases.

  According to a third aspect of the present invention, in the first or second aspect of the invention, the variable means changes the variable setting mode in accordance with the temperature when the temperature control device is stopped.

  The lower the temperature of the temperature parameter at the time of stopping the temperature control device, the smaller the amount of change in the temperature parameter for the longer period from when the temperature control device is stopped to when the temperature control of the heating means is started. This means that the period depends not only on the amount of change in the temperature parameter but also on the value of the temperature parameter when the temperature control device is stopped. In the above invention, in view of this point, by changing the variable setting mode according to the value of the temperature parameter when the temperature control device is stopped, from the time when the temperature control device is stopped until the temperature control of the heating means is started. It is possible to variably set the energization operation mode more appropriately according to the period.

  According to a fourth aspect of the present invention, in the third aspect of the present invention, the heating means can control the temperature as desired by setting the power supplied by the energization operation to a predetermined rated power smaller than the maximum value. The variable means sets the rated power to the amount of power supplied to the heat generating means when the temperature control is started when the temperature when the temperature control device is stopped is equal to or lower than a predetermined temperature. It is characterized by that.

  When the temperature parameter is low when the temperature control device is stopped, the change of the temperature parameter in the period from the stop of the temperature control device to the start of temperature control of the heating means becomes slow. For this reason, when the temperature of the temperature parameter when the temperature control device is stopped is low, it is difficult to specify whether the change of the temperature parameter is slow or the period is short based on the change amount. Therefore, in the above invention, by setting the amount of power supplied to the heat generating means to the rated power under such circumstances, excessive power is supplied in a situation where the period of time is short and the temperature of the heat generating means is not sufficiently lowered, and the heat generating means is overheated. Can be avoided.

  According to a fifth aspect of the present invention, in the invention according to the fourth aspect, the variable means includes a condition that the temperature when the temperature control device is stopped is equal to or less than a predetermined temperature, and the change amount is a predetermined threshold value. When the logical product condition of the following condition is satisfied, the amount of power supplied to the heat generating means at the start of the temperature control is set as the rated power.

  Even if the temperature parameter is low when the temperature control device is stopped, if the amount of change is large, the period from when the temperature control device is stopped to when the temperature control of the heat generating unit is started is long. It can be judged. For this reason, in such a situation, it is desirable to set the energization operation mode according to the period in order to quickly set the temperature of the heating means to the target temperature. In this regard, in the above invention, when the condition that the temperature when the temperature control device is stopped is equal to or lower than a predetermined temperature and the condition that the amount of change is equal to or less than a predetermined threshold are simultaneously satisfied, The power supplied to is the rated power. For this reason, variable setting of the energization operation mode according to the period can be performed as much as possible, and as a result, the temperature of the heat generating means can be controlled more appropriately.

  According to a sixth aspect of the present invention, in the invention according to any one of the first to fifth aspects, the heat generating means sets the power supplied by the energization operation to a predetermined rated power smaller than a maximum value, so that the temperature is increased. Can be controlled as desired, and the variable means uses, as the change amount, a basic pattern that shifts the supply power accompanying the start of the temperature control from a power larger than the rated power to the rated power. The correction is based on this.

  According to the above invention, the target temperature can be realized by supplying the rated power during the temperature control of the heat generating means. However, at the start of temperature control of the heat generating means, if the rated power is supplied, the time until the target temperature is followed may be longer. On the other hand, according to the above-mentioned invention, as the supply power accompanying the start of the temperature control, the heating means is provided from the time when the temperature control device is stopped by providing the basic pattern for shifting from the power larger than the rated power to the rated power. Except when the period until the temperature control is started is excessively short, the temperature of the heating means can be quickly set to the target temperature with this basic pattern. And when the said period is short, it can avoid that the temperature of a heat generating means rises excessively by correct | amending a basic pattern.

  The invention according to claim 7 is the invention according to any one of claims 1 to 6, wherein at least one of the means for detecting the temperature of the cooling water of the internal combustion engine and the means for detecting the exhaust temperature of the internal combustion engine is detected. An acquisition means for acquiring a value is further provided, wherein the variable means uses the detection value acquired by the acquisition means as a temperature having a correlation with the operation history of the internal combustion engine.

  In the above invention, by using the detection value of the means for detecting the cooling water temperature of the internal combustion engine and the means for detecting the exhaust temperature of the internal combustion engine, the temperature control of the heat generating means is started from when the temperature control device is stopped. It is possible to acquire temperature information having a significant correlation with the period.

(First embodiment)
Hereinafter, a first embodiment in which a temperature control device for heat generating means according to the present invention is applied to a temperature control device for a glow plug mounted on an in-vehicle diesel engine will be described with reference to the drawings.

  FIG. 1 shows the overall configuration of the engine system according to the present embodiment.

  As shown in the figure, the intake passage 12 of the diesel engine 10 is communicated with a combustion chamber 20 defined by a cylinder block 16 and a piston 18 by an opening operation of the intake valve 14. In the combustion chamber 20, the tip of the fuel injection valve 22 is disposed so as to protrude. As a result, fuel can be supplied to the combustion chamber 20 by injection. The combustion chamber 20 is provided with a glow plug 24 as heat generating means protruding into the combustion chamber 20.

  When the fuel is injected into the combustion chamber 20, the fuel self-ignites due to the compression of the combustion chamber 20, and energy is generated. This energy is taken out as rotational energy of the output shaft (crankshaft 26) of the diesel engine 10 via the piston 18. A crank angle sensor 28 that detects the rotation angle of the crankshaft 26 is provided in the vicinity of the crankshaft 26. Further, cooling water flows through the cylinder block 16 in order to suppress the temperature rise of the diesel engine 10 due to the combustion of the fuel. The cylinder block 16 is provided with a water temperature sensor 30 for detecting the temperature of the cooling water.

  After the fuel is injected into the combustion chamber 20 through the fuel injection valve 22 and combustion occurs, the gas used for the combustion is discharged into the exhaust passage 34 as exhaust gas by the opening operation of the exhaust valve 32. The exhaust passage 34 is provided with an exhaust temperature sensor 36 for detecting the exhaust temperature.

  The electronic control unit (ECU 40) includes a microcomputer and a constant memory holding memory 42. Here, the always-on memory holding memory 42 is a backup RAM that always holds the power supply state regardless of the state of the ignition switch IG (power switch of the ECU 40), a non-volatile memory that always holds data regardless of whether power is supplied, or the like. A storage device that holds data regardless of the state of the power switch.

  The electric power of the battery B is supplied to the ECU 40 via the ignition switch IG, the main relay 44, and the power supply line L1. The main relay 44 short-circuits the battery B and the power supply line L1 when the ignition switch IG is turned on or a drive signal is input from the signal line L2. For this reason, when the ignition switch IG is turned on, the battery B and the power supply line L1 are brought into conduction by the main relay 44, so that the electric power of the battery B is supplied to the ECU 40.

  On the other hand, the ECU 40 monitors the on / off state of the ignition switch IG via the signal line L3 when electric power is supplied from the battery B. When the ignition switch IG is turned off, a drive signal is output to the main relay 44 via the signal line L2 in order to continue power supply to the ECU 840 until the post-processing performed before stopping the ECU 40 is completed. . Thereby, even after the ignition switch IG is turned off, the electric power of the battery B is supplied to the ECU 80 via the main relay 44 and the power supply line L1 until the post-processing is completed.

  The ECU 40 operates various actuators such as the fuel injection valve 22 on the basis of detection values of various sensors that detect the operation state of the diesel engine 10 and user requests, and thereby output characteristics (output torque, exhaust gas) of the diesel engine 10. Control). In particular, the ECU 40 controls the temperature of the glow plug 24 via a glow plug drive circuit (GDU 50) in order to improve the ignitability of fuel when the diesel engine 10 is cold started.

  The GDU 50 includes a control circuit 52 and a switching element 54. Here, the switching element 54 conducts and blocks between the battery B and the glow plug 24. On the other hand, the control circuit 52 is a circuit for turning on and off the switching element 54 based on a command from the ECU 40. That is, when a command value (command duty) of a duty signal corresponding to the amount of power supplied to the glow plug 24 is output from the ECU 40, the control circuit 52 operates the switching element 54 so that the command duty is obtained. Here, the command Duty is set to a value for setting the amount of supplied power for setting the temperature of the glow plug 24 to the target temperature regardless of the fluctuation of the voltage of the battery B. The target temperature is set to a temperature that improves the ignitability at the time of cold start of the diesel engine 10 and is equal to or lower than the allowable upper limit temperature of the glow plug 24.

  FIG. 2 shows an energization mode of the glow plug 24 by the cooperation of the ECU 40 and the GDU 50. Specifically, FIG. 2A shows the transition of the voltage of the battery B, FIG. 2B shows the transition of the command duty output from the ECU 40, and FIG. 2C shows the switching element 54 in the GDU 50. A transition of the operation duty is shown, and a transition of the energization amount of the glow plug 24 is shown in FIG. As shown in the figure, since the command duty is corrected in accordance with the transition of the voltage of the battery B, an appropriate energization is performed so that the temperature of the glow plug 24 becomes the target temperature regardless of the voltage of the battery B. 24.

  The glow plug 24 according to the present embodiment has a power supply (rated power) that is lower than the maximum power supplied by the battery B (power supplied when the voltage of the battery B is set to 100% Duty at a reference voltage (for example, “12 V”)). ), Which can set the temperature of the glow plug 24 to the target temperature. Therefore, the ECU 40 may set the command duty to a predetermined value less than “100%” in order to set the temperature of the glow plug 24 to the target temperature. However, if the command Duty is set to the predetermined value from the start of temperature control of the glow plug 24, the temperature of the glow plug 24 cannot be quickly set to the target temperature. For this reason, in this embodiment, when starting temperature control, the basic pattern about the electric power supply made to transfer from electric power larger than rated electric power to rated electric power is used.

  FIG. 3 shows an aspect of temperature control start processing of the glow plug 24 using the basic pattern. Specifically, FIG. 3A shows the transition of the command duty, and FIG. 3B shows the transition of the temperature of the glow plug 24.

  As shown in the figure, the command duty becomes the maximum value when the temperature control is started, and thereafter, gradually shifts to a value Da corresponding to the rated power. Thereby, supply electric power can be shifted in steps from a maximum value to rated electric power. Here, in the present embodiment, the number of reduction steps of the supplied power when shifting to the rated power is set to “2” or more (here, “3” is illustrated). This is because the temperature of the glow plug 24 can be controlled to the target temperature by adapting the period of maximum value, but thereafter the supplied power is reduced to the rated power at a stroke as shown by the two-dot chain line in the figure. This is because the temperature of the glow plug 24 may once decrease. This is because, even if the temperature of the tip portion of the glow plug 24 once reaches the target temperature, the rear end portion of the glow plug 24 and the cylinder of the diesel engine 10 are still at a low temperature, so that heat energy flows to them. It is thought that this is a phenomenon that occurs in In order to avoid such a situation, in the present embodiment, the number of reduction steps of the supplied power when shifting to the rated power is set to “2” or more.

  When feedforward control of the temperature of the glow plug 24 is performed using the basic pattern, the controllability depends on the initial temperature of the glow plug 24 at the start of temperature control of the glow plug 24. Here, since the energization of the glow plug 24 is stopped after the start of the diesel engine 10 is completed, the temperature of the glow plug 24 is lowered to the ambient temperature in order to realize a thermal equilibrium state with the surroundings. Therefore, normally, at the time of cold start of the diesel engine 10 where it is desired to start the temperature control of the glow plug 24, the temperature of the glow plug 24 is the ambient temperature (eg, “−40 ° to −20 °”). Match. Although there is a range in temperature at this time, this can be ignored in comparison with the difference between the ambient temperature and the target temperature (for example, “1000 ° C.”). Therefore, in such a case, the temperature of the glow plug 24 can be appropriately controlled to the target temperature by feedforward control using the basic pattern.

  However, for example, when the ignition switch IG is turned on and the temperature control of the glow plug 24 is started and then the ignition switch IG is turned off and turned on again in a short time, the glow plug 24 is It still does not achieve thermal equilibrium with its surroundings. FIG. 4 illustrates a temperature control mode of the glow plug 24 in such a state. Specifically, FIG. 4A shows the transition of the operation mode of the ignition switch IG, FIG. 4B shows the transition of the temperature of the glow plug 24, and FIG. 4C shows the transition to the glow plug 24. The transition of the amount of power supply (command duty) is shown.

  As shown in the figure, in this case, when the temperature control (re-energization) of the glow plug 24 is performed again, the temperature of the glow plug 24 does not coincide with the ambient temperature and is in a high temperature state. In this case, the temperature of the glow plug 24 rises above the target temperature by supplying power using the basic pattern.

  On the other hand, for example, as shown in FIG. 5, if the supplied power at the start of the temperature of the glow plug 24 is the rated power, it can be said that the actual temperature can be prevented from rising beyond the target temperature. The followability to the target temperature is reduced. 5A to 5C correspond to the previous FIG. 4A to FIG. 4C.

  Therefore, in the present embodiment, the basic pattern is corrected based on the amount of change in the cooling water temperature detected by the water temperature sensor 30 from when the ECU 40 stops until the temperature control of the glow plug 24 starts. The coolant temperature has a correlation with the operation history of the diesel engine 10. For this reason, the coolant temperature rises with the operation of the diesel engine 10. When the diesel engine 10 is stopped in this state, the cooling water temperature gradually decreases. Here, the amount of decrease in the cooling water temperature in the period from when the diesel engine 10 is stopped and the ECU 40 is stopped until when the temperature control of the glow plug 24 is started again in accordance with the ON operation of the ignition switch IG is as described above. Depends on the length of the period. For this reason, the length of the said period can be grasped | ascertained based on the variation | change_quantity of the said cooling water temperature. By correcting the basic pattern according to the length of the period thus grasped, the temperature of the glow plug 24 can be prevented from rising above the target temperature due to the energization operation.

  FIG. 6 shows a temperature control mode of the glow plug 24 according to the present embodiment. Specifically, FIG. 6A shows the transition of the operation mode of the ignition switch IG, FIG. 6B shows the transition of the state of the ECU 40, and FIG. 6C shows the power supplied to the glow plug 24. The transition of the amount (command duty) is shown, and the transition of the cooling water temperature is shown in FIG.

  As shown in the figure, the coolant temperature decreases as the ignition switch IG is turned off. On the other hand, when the ignition switch IG is turned off, the ECU 40 stores the coolant temperature THW1 at that time and then stops. Thereafter, when the ignition switch IG is turned on again, the ECU 40 calculates a change amount ΔTHW of the current cooling water temperature THW2 with respect to the cooling water temperature THW1 when the ignition switch IG is turned off. This amount of change ΔTHW has a correlation with the time “T3−T1” from when the ignition switch IG is stopped until it is turned on again this time. Therefore, the temperature control of the glow plug 24 is performed while correcting the basic pattern based on the change amount ΔTHW. Specifically, in the present embodiment, correction is performed to shorten the period during which the amount of supplied power is maximized. This is because the purpose of raising the temperature of the glow plug 24 to the target temperature during the period in which the amount of supplied power is maximum. For this reason, when the amount of change ΔTHW is small and the time “T3-T1” from when the ignition switch IG is stopped to when it is turned on again is considered short, the temperature of the glow plug 24 is not sufficiently lowered. Since the initial temperature is considered high, the time for supplying the maximum amount of power is corrected to be shortened.

  However, as shown in FIG. 7, when the coolant temperature THW1 when the ignition switch IG is turned off is low, the time “T3-T1” from when the ignition switch IG is turned off to when it is turned on again this time However, the amount of change ΔTHW in the cooling water temperature is small. For this reason, in such a situation, it is determined whether the amount of change ΔTHW is small because the time “T3−T1” is short or because the cooling water temperature THW1 is low and the cooling water temperature decreases slowly. You may not be able to. For this reason, in such a situation, when the temperature control of the glow plug 24 is started, the rated power is supplied in order to avoid the temperature of the glow plug 24 from exceeding the target temperature.

  8 and 9 show the temperature control processing procedure of the glow plug 24. FIG. The process shown in FIG. 8 is repeatedly executed by the ECU 40, for example, at a predetermined cycle.

  In the series of processes shown in FIG. 8, it is first determined in step S10 whether or not the ignition switch IG has been turned off. When it is determined that the ignition switch IG is turned off, the detected value (cooling water temperature THW1) of the water temperature sensor 30 at that time is always stored in the memory holding memory 42. Thereafter, the ECU 40 stops energization of the ECU 40 by turning off the main relay 44.

  The process shown in FIG. 9 is triggered by an ON operation of the ignition switch IG.

  In the series of processing shown in FIG. 9, first, in step S20, the detection value (cooling water temperature THW2) of the water temperature sensor 30 is acquired. In the subsequent step S22, it is determined whether or not the glow plug 24 is energized. Here, for example, it may be determined that there is an energization request when the coolant temperature THW2 is equal to or lower than a predetermined temperature. When it is determined that there is an energization request, in step S24, a change amount ΔTHW of the current cooling water temperature THW2 with respect to the cooling water temperature THW1 when the ignition switch IG is turned off is calculated.

  After such processing, when the absolute value of the change amount ΔTHW is equal to or less than the threshold value ΔT (step S26: YES) and the coolant temperature THW1 is equal to or less than the specified temperature THW0 (step S28: YES), the process proceeds to step S30. The rated power is supplied from the beginning of the temperature control of the glow plug 24. As illustrated in FIG. 7, when the cooling water temperature THW1 is low, the reason why the change amount ΔTHW is small is that the time from when the ignition switch IG is stopped until it is turned on again this time “T3-T1 "Is short, or because the rate of decrease in the cooling water temperature is dull.

  On the other hand, when the absolute value of the change amount ΔTHW is larger than the threshold value ΔT (step S26: NO), or when the coolant temperature THW1 is higher than the specified temperature THW0 (step S28: NO), the process proceeds to step S32. The basic pattern is corrected based on the change amount ΔTHW. Specifically, here, the maximum power supply time of the basic pattern is multiplied by the correction coefficient shown in FIG. The correction coefficient increases as the change amount ΔTHW increases and converges to “1”. For this reason, as the change amount ΔTHW is larger, the maximum power supply time to the glow plug 24 is closer to that in the basic pattern. When the correction coefficient is “0”, it is desirable to correct the entire basic pattern so that the rated power flows, not just the correction of the maximum power supply time.

  When a negative determination is made in step S22 shown in FIG. 9 or when the processes in steps S30 and S32 are completed, this series of processes is temporarily ended.

  According to the embodiment described in detail above, the following effects can be obtained.

  (1) Based on the amount of change ΔTHW in the cooling water temperature, the energization operation mode by feedforward control is variably set. As a result, it is possible to perform an appropriate energization operation for the initial temperature of the glow plug 24 and to control the target temperature with high accuracy.

  (2) The larger the amount of change ΔTHW, the greater the amount of power supplied at the start of temperature control. Thereby, the temperature of the glow plug 24 can be quickly controlled to the target temperature regardless of the length of time from when the ignition switch IG is stopped until it is turned on again.

  (3) When the coolant temperature THW1 is equal to or lower than the specified temperature THW0, the amount of power supplied to the glow plug 24 at the start of temperature control is set as the rated power. As a result, depending on the amount of change ΔTHW, the glow plug 24 may be overheated even in a situation where it is difficult to identify the length of time from when the ignition switch IG is stopped to when it is turned on again. It can be avoided.

  (4) As a condition for setting the rated power at the start of temperature control, a logical product condition of a condition that the coolant temperature THW1 is equal to or less than the specified temperature THW0 and a condition that the change amount ΔTHW is equal to or less than the threshold value ΔT is used. Thereby, the temperature of the glow plug 24 can be controlled more appropriately.

  (5) The supply power accompanying the start of temperature control is set by correcting the basic pattern for shifting from the power larger than the rated power to the rated power based on the change amount ΔTHW. As a result, the temperature of the glow plug 24 can be quickly set to the target temperature with this basic pattern, except when the time from when the ignition switch IG is stopped until it is turned on again is excessively short. And when the said period is short, it can avoid that the temperature of the glow plug 24 rises excessively by correct | amending a basic pattern.

  (6) By using the coolant temperature as a temperature having a correlation with the operation history of the diesel engine 10, temperature information having a significant correlation with the time from when the ignition switch IG is stopped until it is turned on again is acquired. Can do.

(Second Embodiment)
Hereinafter, the second embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  FIG. 11 shows a temperature control processing procedure of the glow plug 24 according to the present embodiment. This process is started when the ignition switch IG is turned on. In FIG. 11, the same steps as those in FIG. 9 are given the same step numbers for the sake of convenience.

  In this series of processes, after the process of step 24, in step S40, the basic pattern is corrected based on the variation ΔTHW and the coolant temperature THW1. This is because the degree of decrease in the coolant temperature associated with turning off the ignition switch IG depends on the coolant temperature THW1 when the ignition switch IG was previously turned off. In this correction, a map that defines the relationship between the variation ΔTHW and the correction coefficient when the coolant temperature THW1 shown in FIG. 12A is a high temperature TH and the coolant temperature THW1 shown in FIG. 12B is a low temperature TL. This is performed by using either or both of a map that defines the relationship between the amount of change ΔTHW and the correction coefficient. That is, when the coolant temperature THW1 matches any one of these temperatures, the correction coefficient is determined by the corresponding map. On the other hand, when the coolant temperature THW1 is not any of these temperatures, the final correction coefficient is determined by interpolation calculation of the correction coefficient determined from each map.

  Here, the correction coefficient is set to take a larger value with a smaller change amount ΔTHW as the coolant temperature THW1 is lower. This is because the cooling water temperature decreasing speed associated with turning off the ignition switch IG becomes duller as the cooling water temperature THW1 when the ignition switch IG was previously turned off is lower.

  In the present embodiment, the correction coefficient is a coefficient that uniformly corrects a power supply period that is greater than the rated power, as shown in FIG. For this reason, when the correction coefficient is “0”, the rated power is supplied.

  According to the present embodiment described above, the following effects can be obtained in addition to the effects according to the above-described effects of the first embodiment.

  (7) The correction coefficient can be calculated more appropriately by providing a map that defines the relationship between the change amount ΔTHW and the correction coefficient for each of the plurality of cooling water temperatures THW1.

(Third embodiment)
Hereinafter, the third embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  In the present embodiment, the exhaust gas temperature detected by the exhaust gas temperature sensor 36 is used instead of the cooling water temperature detected by the water temperature sensor 30. Since the exhaust temperature also has a significant correlation with the operation history of the diesel engine 10, the amount of change in the exhaust temperature in the period from when the ignition switch IG is stopped until it is turned on again appropriately represents the length of the same period Parameter. The temperature control of the glow plug 24 according to the present embodiment can be realized by setting the cooling water temperature to the exhaust gas temperature in FIGS.

  However, the map that defines the relationship between the change amount of the exhaust temperature and the correction coefficient shown in FIG. 13 makes the change degree of the correction coefficient relative to the change of the change gentle compared to the map shown in FIG. It is desirable. This is because the exhaust temperature has a lower rate of decrease than the cooling water temperature.

  Also according to the present embodiment described above, it is possible to obtain effects according to the above-described effects of the first embodiment.

(Other embodiments)
Each of the above embodiments may be modified as follows.

  In the second embodiment, each of the two values of the coolant temperature THW1 is provided with a separate map, but each of the three or more values may be provided with a separate map. Furthermore, a two-dimensional map that defines the relationship between the coolant temperature THW1, the variation ΔTHW, and the correction coefficient may be used.

  When the coolant temperature THW1 is high to some extent, it is considered that the diesel engine 10 has been sufficiently warmed up by the operation of the diesel engine 10. For this reason, in this case, it is considered that time has passed since the energization operation of the glow plug 24 was completed. Therefore, when the cooling water temperature THW1 when the ignition switch IG is off is equal to or higher than a predetermined temperature (for example, near the assumed maximum temperature of the cooling water temperature) when the diesel engine 10 is warmed up, the basic pattern is You may make it use.

  In the third embodiment, the cooling water temperature in the first embodiment is replaced with the exhaust temperature, but the cooling water temperature in the second embodiment or the modified example thereof may be replaced with the exhaust temperature.

  -As a basic pattern, it is not restricted to what was illustrated by the said embodiment. For example, the configuration may be such that the supplied power is continuously reduced to the rated power after the maximum power supply period ends.

  In addition, the feedforward control is not limited to correcting the basic pattern related to the supplied power amount according to the change amount ΔTHW, but may directly set the supplied power pattern based on the change amount ΔTHW or the like.

  The temperature having a correlation with the temperature of the diesel engine 10 is not limited to those exemplified in the above embodiments. For example, both of these temperature parameters may be used in combination. Further, for example, if the diesel engine 10 is mounted on a vehicle equipped with an automatic transmission (AT), the temperature of the AT hydraulic fluid may be used. Furthermore, for example, in the case of a device provided with detection means for detecting the temperature in the drive circuit for driving the fuel injection valve 22, the temperature may be used.

  -The structure of GDU50 is not restricted to what was illustrated by the said embodiment. At this time, the ECU 40 is not limited to the command value for supplying power to the glow plug 24 as the command duty, and for example, the supplied power amount itself may be used as the command value.

  -The internal combustion engine is not limited to a compression ignition type internal combustion engine such as a diesel engine, but even a spark ignition type internal combustion engine such as a gasoline engine burns to compensate for a decrease in fuel ignitability when starting in a low temperature state. If the heating means protruding in the room is provided, it is effective to apply the present invention to the temperature control.

The figure which shows the whole structure of the engine system concerning 1st Embodiment. The time chart which shows the electricity supply operation aspect of the glow plug concerning the embodiment. The time chart which shows the control aspect at the time of the temperature control start of the glow plug concerning the embodiment. The time chart which shows the problem of temperature control of a glow plug. The time chart which shows another problem of temperature control of a glow plug. The time chart which shows the temperature control aspect of the glow plug concerning the said embodiment. The time chart which shows the temperature control aspect of the glow plug concerning the embodiment. The flowchart which shows the process sequence of the temperature control of the glow plug concerning the embodiment. The flowchart which shows the process sequence of the temperature control of the glow plug concerning the embodiment. The figure which shows the map used for the temperature control of the glow plug concerning the embodiment. The flowchart which shows the process sequence of the temperature control of the glow plug concerning 2nd Embodiment. The figure which shows the map etc. which are used for the temperature control of the glow plug concerning the embodiment. The figure which shows the map used for the temperature control of the glow plug concerning 3rd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Diesel engine, 20 ... Combustion chamber, 24 ... Glow plug, 30 ... Water temperature sensor, 36 ... Exhaust temperature sensor, 40 ... ECU (one Embodiment of the temperature control apparatus of a heat generating means).

Claims (7)

In the temperature control device of the heat generating means for performing energization operation to the heat generating means in order to feedforward control the temperature of the heat generating means protruding into the combustion chamber of the internal combustion engine,
Variable means for variably setting the power supply operation mode by the feedforward control based on the amount of change from the stop of the temperature control device to the start of temperature control of the heat generating means for the temperature having a correlation with the operation history of the internal combustion engine A temperature control device for heat generating means.   2. The temperature control apparatus for a heating means according to claim 1, wherein the variable means increases the amount of power supplied at the start of the temperature control as the change amount increases.   3. The temperature control device for a heating means according to claim 1, wherein the variable means changes the variable setting mode according to the temperature when the temperature control device is stopped. The heating means can control the temperature as desired by setting the power supplied by the energization operation to a predetermined rated power smaller than the maximum value,
The variable means is characterized in that when the temperature when the temperature control device is stopped is equal to or lower than a predetermined temperature, the amount of power supplied to the heat generating means at the start of the temperature control is the rated power. The temperature control device for heat generating means according to claim 3.   The variable means is configured such that when a logical product condition of a condition that the temperature when the temperature control device is stopped is equal to or lower than a predetermined temperature and a condition that the amount of change is equal to or lower than a predetermined threshold is satisfied. 5. The temperature control device for power generation means according to claim 4, wherein an amount of electric power supplied to the heat generation means at the start of temperature control is the rated power. The heating means can control the temperature as desired by setting the power supplied by the energization operation to a predetermined rated power smaller than the maximum value,
The said variable means correct | amends the basic pattern which transfers the electric power accompanying the start of the said temperature control from the electric power larger than the said rated electric power to the said rated electric power based on the said variation | change_quantity. The temperature control device for the heating means according to any one of the above. An acquisition means for acquiring a detection value of at least one of a means for detecting the temperature of the cooling water of the internal combustion engine and a means for detecting the exhaust temperature of the internal combustion engine;
The temperature control of the heating means according to any one of claims 1 to 6, wherein the variable means uses a detection value acquired by the acquisition means as a temperature having a correlation with an operation history of the internal combustion engine. apparatus.

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