Control device, transport refrigeration apparatus, and control method

Abstract

To provide a control device capable of properly controlling energization to a glow plug, a refrigerating device for transportation, and a control method.SOLUTION: The control device includes an acquisition unit which acquires information indicating a terminal voltage of a starting battery of the engine, a pre-glow period calculation unit which calculates a pre-glow period which is a time from an operation start of a glow plug which heats a combustion chamber of the engine to a drive start of a starter of the engine based on the terminal voltage, a glow plug control unit which turns on the glow plug at a start time of the pre-glow period and turns off the glow plug when starting of the engine is successful, and a prohibition period setting unit which sets a prohibition period which is a period in which turning on of the glow plug is prohibited after the glow plug is turned off.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a control device, a transport refrigeration device, and a control method. [Background technology]

[0002] In the refrigeration device for land transport described in Patent Document 1, the heat generation amount of starting aid components such as glow plugs is increased or decreased depending on the length of time the engine is stopped, and the heat generation amount of the starting aid components is set based on an estimated value of the outside temperature. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-234322 Summary of the Invention [Problem to be solved by the invention]

[0004] In the refrigeration device for land transport described in Patent Document 1, the amount of heat generated by the starting aid can be adjusted based on the length of time the engine is stopped and the estimated outside temperature, thereby ensuring reliable starting of the engine and extending the life of the starting aid.

[0005] The lifespan of a glow plug decreases as the glow plug temperature increases and as the number of times it is energized increases. Glow plugs become hot when they are energized for a long time or at a high voltage, or when they are energized multiple times consecutively with short de-energization intervals. Repeated energization with short de-energization intervals can occur, for example, when restarting an engine after a failed start. In this case, the engine remains stopped, so the engine stop time does not change between the first and second energizations. Therefore, the refrigeration system for land transportation described in Patent Document 1 has a problem in that some kind of countermeasure may be required to deal with repeated energization with short de-energization intervals.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a control device, a transport refrigeration device, and a control method that can appropriately control the supply of electricity to glow plugs. [Means for solving the problem]

[0007] In order to solve the above-described problems, a control device according to the present disclosure includes an acquisition unit that acquires information indicating a terminal voltage of a starting battery of an engine, a pre-glow period calculation unit that calculates a pre-glow period, which is a time from when a glow plug that heats a combustion chamber of the engine starts to be driven until a starter of the engine starts to be driven, based on the terminal voltage, a glow plug control unit that turns on the glow plug at the start of the pre-glow period and turns off the glow plug when the engine is successfully started, and a prohibition period setting unit that sets a prohibition period, which is a period during which turning on of the glow plug is prohibited after the glow plug is turned off, and the glow plug control unit does not turn on the glow plug during the prohibition period.

[0008] The transport refrigeration unit according to the present disclosure includes the control device, the engine, and a refrigeration unit that operates using the engine as a power source.

[0009] The control method according to the present disclosure includes the steps of: acquiring information indicating a terminal voltage of a starting battery of an engine; calculating a pre-glow period, which is a time period from when a glow plug that heats a combustion chamber of the engine starts to be driven until when a starter of the engine starts to be driven, based on the terminal voltage; turning on the glow plug at the start of the pre-glow period; turning off the glow plug when the engine is successfully started; and setting a prohibition period, which is a period during which turning on of the glow plug is prohibited after the glow plug is turned off; and in the step of turning on the glow plug at the start of the pre-glow period, the glow plug is not turned on during the prohibition period. [Effects of the Invention]

[0010] According to the control device, transport refrigeration device, and control method of the present disclosure, it is possible to appropriately control the supply of electricity to the glow plug. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a block diagram illustrating a configuration example of a transport refrigeration device according to a first embodiment of the present disclosure. [Figure 2] 1 is an electrical circuit diagram showing a configuration example of a transport refrigeration device according to a first embodiment of the present disclosure. [Figure 3] FIG. 2 is a diagram illustrating an example of an engine start sequence according to the first embodiment of the present disclosure. [Figure 4] FIG. 3 is a diagram showing temperature rise characteristics of the combustion chamber of the engine according to the first embodiment of the present disclosure. [Figure 5] FIG. 4 is a diagram showing engine startability when the engine is hot according to the first embodiment of the present disclosure. [Figure 6] FIG. 3 is a diagram showing the temperature drop characteristics of the glow plug according to the first embodiment of the present disclosure. [Figure 7] 3A and 3B are diagrams for explaining an example of control of a glow plug according to the first embodiment of the present disclosure. [Figure 8] 3A and 3B are diagrams for explaining an example of control of a glow plug according to the first embodiment of the present disclosure. [Figure 9] 4 is a flowchart showing an example of operation of the transport refrigeration device according to the first embodiment of the present disclosure. [Figure 10] 4 is a flowchart showing an example of operation of the transport refrigeration device according to the first embodiment of the present disclosure. [Figure 11] 4 is a flowchart showing an example of operation of the transport refrigeration device according to the first embodiment of the present disclosure. [Figure 12] FIG. 10 is a diagram illustrating an example of an engine start sequence according to a second embodiment of the present disclosure. [Figure 13] 10 is a flowchart showing an example of operation of the transport refrigeration system according to the second embodiment of the present disclosure. [Figure 14] 10 is a flowchart showing an example of operation of the transport refrigeration system according to the second embodiment of the present disclosure. [Figure 15] FIG. 1 is a schematic block diagram illustrating the configuration of a computer according to at least one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] A control device, a transport refrigeration device, and a control method according to an embodiment of the present disclosure will be described below with reference to Figures 1 to 15. Note that the same or corresponding components in each figure are designated by the same reference numerals, and descriptions thereof will be omitted as appropriate.

[0013] First Embodiment FIG. 1 is a block diagram showing an example configuration of a transport refrigeration system 1 according to an embodiment of the present disclosure. FIG. 2 is an electrical circuit diagram showing an example configuration of a transport refrigeration system 1 according to a first embodiment of the present disclosure. The transport refrigeration system 1 shown in FIG. 1 is installed in a truck for land transport, a container for rail transport, or the like. The transport refrigeration system 1 includes a diesel engine 11, a refrigerator 12, a generator 13, a battery 14, a control board 15, and an AC (alternating current) / DC (direct current) converter 16. The control board 15 is an example configuration of a "control device" according to the present disclosure.

[0014] The refrigerator 12 includes a compressor 121, a condenser 122, an expansion valve 124, an evaporator 123, a refrigerator control board 125, refrigerator sensors 126, and auxiliary equipment such as a fan (not shown). The refrigerator 12 works in conjunction with the control board 15 and controls the temperature inside a compartment installed in a truck, container, or the like, for example, for freezing or refrigeration, based on output signals from the refrigerator sensors 126. The refrigerator sensors 126 include a plurality of sensors, such as a temperature sensor and a pressure sensor. The refrigerator control board 125 is configured using a computer, such as a microcontroller. The compressor 121 is an electric compressor equipped with a driving motor M1. The motor M1 is controlled by the refrigerator control board 125.

[0015] The diesel engine 11 is a power source used to drive the compressor 121. The diesel engine 11 is one example of an "engine" according to the present disclosure and will also be referred to as the "engine 11" hereinafter. The diesel engine 11 is an engine for a refrigerator 12, separate from an engine for driving a truck, for example. The operation of the diesel engine 11 is controlled by a control board 15. The diesel engine 11 includes a glow plug 111 for heating a combustion chamber of the diesel engine 11, a temperature sensor 112 for detecting the temperature of the cooling water of the diesel engine 11, and a starter (motor) 113 as a starting device for the diesel engine 11. The glow plug 111 includes a resistance heater that heats its tip when energized. The pre-heating time required for the glow plug 111 to heat up to a temperature required to start the diesel engine 11 is referred to as a pre-glow time. The diesel engine 11 also includes actuators (not shown), such as a fuel injection device and a fuel pump, and sensors (not shown), such as an engine rotation speed (rotational speed) sensor.

[0016] The transport refrigeration system 1 also includes a relay (relay 181 in FIG. 2) that turns on or off the energized state of the glow plug 111, and a relay (relay 182 in FIG. 2) that turns on or off the energized state of the starter 113. The relay 181 shown in FIG. 2 includes a contact 181a and a coil 181b. The relay 182 shown in FIG. 2 includes a contact 182a and a coil 182b. In the example shown in FIG. 2, the positive terminal of the battery 14, one end of a series circuit of the starter 113 and the contact 182a, one end of a series circuit of four parallel circuits of glow plugs 111 (hereinafter simply referred to as glow plugs 111) and the contact 181a, and the positive power supply terminal of the control board 15 are connected to a + (plus) terminal 161 of the AC / DC converter 16. In addition, the negative terminal 162 of the AC / DC converter 16 is connected to the negative terminal of the battery 14, the other end of the series circuit between the starter 113 and contact 182a, the other end of the series circuit between the glow plug 111 and contact 181a, and the negative power supply terminal of the control board 15.

[0017] The battery 14 is a storage battery used when starting the diesel engine 11, and is one example of a "starting battery" according to the present disclosure. The battery 14 is, for example, a lead battery. When starting the diesel engine 11, actuators for warming up and supplying fuel, a starter for starting, and the like are driven by power supplied from the battery 14.

[0018] The generator 13 is mechanically driven by the diesel engine 11 via a belt 17 to generate three-phase AC power. The AC power generated by the generator 13 is converted into DC power by an AC / DC converter 16 and used to charge the battery 14 and to operate the refrigerator 12, the control board 15, etc.

[0019] The control board 15 controls each part (each device) in the transport refrigeration system 1, such as the diesel engine 11 and the refrigerator 12. For example, the control board 15 starts and stops the diesel engine 11 and controls the output of the diesel engine 11 according to the load on the refrigerator 12. As shown in FIG. 2 , the control board 15 includes a computer 151 such as a microcontroller, MOSFETs (metal-oxide semiconductor field-effect transistors) 152 and 153, and the like. The MOSFET 152 controls the conduction state (operating state) of the glow plug 111 by turning on or off the coil 181b and turning on or off the contact 181a. The MOSFET 153 controls the conduction state (operating state) of the starter 113 by turning on or off the coil 182b and turning on or off the contact 182a. The control board 15 also receives an output signal from a temperature sensor 112.

[0020] The control board 15 includes the following units as functional blocks configured by a combination of hardware such as a computer 151 and software such as a program executed by the computer 151. That is, the control board 15 includes, as functional blocks, an acquisition unit 15F1, a start instruction issuing unit 15F2, a pre-glow period calculation unit 15F3, a glow plug control unit 15F4, a starter control unit 15F5, a prohibition period setting unit 15F6, and a restart control unit 15F7.

[0021] The acquisition unit 15F1 acquires information indicating the terminal voltage of the battery 14 for starting the diesel engine 11, information indicating the coolant temperature of the diesel engine 11 detected by the temperature sensor 112, and the like.

[0022] The start instruction issuing unit 15F2 issues an instruction to start the engine start sequence shown in FIG. 3, for example. FIG. 3 is a diagram showing an example of the engine start sequence according to the first embodiment of the present disclosure. In FIG. 3, the horizontal axis represents time, and the vertical axis represents the ON / OFF of the glow plug 111 and the ON / OFF of the starter 113. In the example shown in FIG. 3, a start instruction is issued at time t1 (immediately thereafter), and the glow plug 111 is changed from OFF to ON. Next, at time t2, when a pre-glow period Tpg has elapsed since time t1, the starter 113 is changed from OFF to ON. Next, at time t3, the diesel engine 11 is successfully started. At time t3, the glow plug 111 is changed from ON to OFF, and the starter 113 is changed from ON to OFF. In addition, the period from time t3 to time t4 is set as a pre-glow inhibit period Tb. The start instruction issuing unit 15F2 issues a start instruction, for example, when a user instructs the diesel engine 11 to start, when the refrigeration machine control board 125 instructs the diesel engine 11 to start, or when restarting the diesel engine 11 after failing to start.

[0023] In the example shown in FIG. 3, the pre-glow period Tpg is a time corresponding to the above-mentioned pre-glow time, and in this embodiment, it is a time from when the glow plug 111 starts operating until the start of driving the starter 113 of the diesel engine 11. Also, the pre-glow prohibition period Tb is a period during which the glow plug 111 is prohibited from being turned on after it is turned off. The pre-glow prohibition period Tb corresponds to the "prohibition period" according to the present disclosure. During the pre-glow prohibition period Tb, the glow plug 111 is not turned on. In the example shown in FIG. 3, the glow plug 111 is turned on at time t4 after the pre-glow prohibition period Tb has elapsed.

[0024] The pre-glow period calculation unit 15F3 calculates a pre-glow period Tpg, which is the time from when the glow plug 111 starts to operate until the start of driving the starter 113, based on the terminal voltage of the battery 14. Note that the pre-glow period calculation unit 15F3 may calculate the pre-glow period Tpg based on the terminal voltage of the battery 14 and the coolant temperature of the diesel engine 11.

[0025] Here, referring to FIGS. 4 to 6, the characteristics of the glow plug 111 during operation or non-operation will be described. FIG. 4 is a diagram showing the temperature increase characteristics of the engine combustion chamber according to the first embodiment of the present disclosure. FIG. 5 is a diagram showing the engine starting performance during engine heat according to the first embodiment of the present disclosure. FIG. 6 is a diagram showing the temperature decrease characteristics of the glow plug 111 according to the first embodiment of the present disclosure.

[0026] FIG. 4 shows the experimental results of the temperature change of the glow plug 111 when the terminal voltage Vph of the glow plug 111 is set as the voltages V11, V12, or V13, with the horizontal axis being the energization time of the glow plug 111 and the vertical axis being the temperature of the glow plug 111. The temperature of the glow plug 111 was measured by a thermocouple temporarily installed for the experiment (note that since the temperature of the glow plug 111 becomes high, it is not practical in the device of this embodiment to measure it by permanently installing a temperature sensor). Incidentally, Vph is the glow plug terminal voltage [V] (= Vbat - ΔV), Vbat is the battery terminal voltage [V], and ΔV is the voltage drop (between the battery terminal and the glow plug). Also, the voltages V11, V12, and V13 have the relationship of V11 < V12 < V13. The solid line represents the characteristics when Vph = V11, the dashed line represents the characteristics when Vph = V12, and the chain line represents the characteristics when Vph = V13. The time from the start of energization until reaching the upper limit temperature (the upper limit temperature at which it can be stably used) is the shortest in the case of V13 and the longest in the case of V11. It can be seen that the higher the glow plug terminal voltage and the longer the energization time, the easier it is for the glow plug 111 to increase in temperature and reach the upper limit temperature.

[0027] FIG. 5 shows a curve representing the change in engine coolant temperature over time after the engine is stopped, with the horizontal axis representing elapsed time and the vertical axis representing engine coolant temperature. It also displays circles on the curve indicating the quality of engine startability when the pre-glow period Tpg is set to 0 seconds (when the glow plug 111 is not activated). Black circles represent good cases (e.g., the engine started with almost no white smoke at the exhaust pipe outlet), and white circles represent bad cases (e.g., the engine started but white smoke was generated). When the engine is hot after being stopped, the combustion chamber temperature is high, ensuring good startability even without pre-glow. In the example shown in FIG. 5, good startability can be ensured even without pre-glow if the coolant temperature is above temperature Twa.

[0028] Figure 6 shows the change in temperature after the glow plug is de-energized, with the horizontal axis representing the time the glow plug is de-energized and the vertical axis representing the glow plug temperature. Figure 6 shows that it takes time for the glow plug to cool down. For example, if the glow plug is re-energized without cooling it sufficiently, it will quickly reach its upper limit temperature.

[0029] The pre-glow period calculation unit 15F3 refers to a table TBL1 as shown in, for example, FIG. 7, and calculates the pre-glow period Tpg based on the terminal voltage Vbat of the battery 14. Also, in the example shown in FIG. 7, the pre-glow period calculation unit 15F3 calculates the pre-glow period Tpg based on the terminal voltage Vbat of the battery 14 and the cooling water temperature Twts. FIG. 7 classifies the battery voltage value Vbat [V] immediately before the start of pre-glow into cases where Vbat ≤ V1, cases where V1 < Vbat ≤ V2, and cases where V2 < Vbat ≤ V3, and also classifies the engine cooling water temperature Twts immediately before the start of pre-glow into cases where Twts ≥ Twa (see FIG. 5) and cases where Twts < Twa, and sets the value of the pre-glow period Tpg. However, the voltage V1 < V2 < V3, and the times T1 > T2 > T3. The lower the voltage, the longer the time. When the cooling water temperature Twts is equal to or higher than a predetermined temperature (temperature Twa), the pre-glow period Tpg is set to zero. In this case, the pre-glow period calculation unit 15F3 sets the pre-glow period Tpg to zero when the cooling water temperature is equal to or higher than the predetermined temperature. In the table TBL1 shown in FIG. 7, the times T1, T2, and T3 are constants, but as shown in FIG. 8, the pre-glow time Tpg may be continuously changed linearly (or curvilinearly) according to the voltage value Vbat. Also, the classification of the engine cooling water temperature Twts is not limited to two cases and may be three or more. Also, the classification of the battery voltage value Vbat may be two or less or four or more.

[0030] The glow plug control unit 15F4 controls the glow plug 111 to be on or off. The glow plug control unit 15F4, for example, turns on the glow plug 111 at the start of the pre-glow period Tpg (time t1 in FIG. 3) and turns off the glow plug 111 when the diesel engine 11 starts successfully (time t3 in FIG. 3). Also, in the present embodiment, the glow plug control unit 15F4 does not turn on the glow plug 111 during the pre-glow prohibition period Tb.

[0031] The starter control unit 15F5 controls the starter 113 to be turned on or off. For example, the starter control unit 15F5 turns on the starter 113 when the pre-glow period Tpg has elapsed (at the end) (time t2 in FIG. 3). The starter control unit 15F5 also determines, for example, whether the engine has been successfully started, and turns off the starter 113 after the engine has been successfully started (time t3 in FIG. 3). Note that the engine has been successfully started when, for example, the diesel engine 11 has been continuously driven at an idling speed for a predetermined period of time.

[0032] The prohibition period setting unit 15F6 sets a pre-glow prohibition period Tb which is a period during which the glow plug 111 is prohibited from being turned on after the glow plug 111 is turned off. The pre-glow prohibition period Tb may start after the glow plug 111 is turned off, or may start after the glow plug 111 and the starter 113 are turned off. The pre-glow prohibition period Tb is set to a value such that no problem occurs even if the glow plug 111 is turned on for a time period obtained by adding together the pre-glow period Tpg shown in Fig. 7 and the time from activation of the starter 113 to start of the engine (the time from time t2 to time t3 in Fig. 3 (cranking time)) when the pre-glow prohibition period Tb has elapsed after the glow plug 111 is turned off.

[0033] For example, if engine start is not successful even after driving the starter 113 for a predetermined time limit, the restart control unit 15F7 reissues the start instruction (or causes the start instruction issuing unit 15F2 to reissue the start instruction) when predetermined conditions (hereinafter also referred to as restart conditions) are satisfied. The time limit can be set based on a limit value for the continuous operation time of the starter 113, etc. If the time limit has elapsed, the starter 113 is temporarily turned off, and then, if the restart conditions are satisfied, the starter 113 is turned on again to attempt to start the engine. The restart condition is, for example, a condition in which starting the engine is difficult, but there is a possibility that starting will be successful if a retry is made. The restart condition is, for example, a condition in which the temperature of the engine coolant is in a predetermined low temperature state, a condition in which the charge state of the battery 14 is at a minimum state required for starting the starter 113, etc.

[0034] Next, an example of the operation of transport refrigeration unit 1 will be described with reference to Figs. 9 to 11. Figs. 9 to 11 are flowcharts showing an example of the operation of transport refrigeration unit 1 according to the first embodiment of the present disclosure. The process shown in Fig. 9 is repeatedly executed at a predetermined cycle after control board 15 is started up. The process shown in Fig. 10 is called by the process of step S122 in Fig. 9. The process shown in Fig. 11 is repeatedly executed at a predetermined cycle after control board 15 is started up. First, the process shown in Fig. 9 will be described.

[0035] (1) Example of operation at start-up of control board 15 (before time t1 in FIG. 3): When the processing shown in FIG. 9 starts, starter control unit 15F5 determines whether or not starter 113 is on (step S101). If starter 113 is not on (step S101: NO), glow plug control unit 15F4 determines whether or not glow plug 111 is on (step S102). If glow plug 111 is not on (step S102: NO), glow plug control unit 15F4 determines whether or not a start command has been issued (step S103). If a start command has not been issued (step S103: NO), glow plug control unit 15F4 ends the processing shown in FIG. 9.

[0036] (2) Example of operation when the start instruction issuing unit 15F2 issues a start instruction (at time t1 in FIG. 3): When the process shown in FIG. 9 starts, the starter control unit 15F5 determines whether the starter 113 is on or not (step S101). If the starter 113 is not on (step S101: NO), the glow plug control unit 15F4 determines whether the glow plug 111 is on or not (step S102). If the glow plug 111 is not on (step S102: NO), the glow plug control unit 15F4 determines whether a start instruction is present or not (step S103). If a start instruction is present (step S103: YES), the glow plug control unit 15F4 determines whether the current period is during the pre-glow inhibit period Tb or not (step S104). If the current period is not during the pre-glow inhibit period Tb (step S104: NO), the acquisition unit 15F1 acquires the battery voltage Vbat (step S105). Next, the acquisition unit 15F1 acquires the coolant temperature Twts (step S106). Next, the pre-glow period calculation unit 15F3 calculates the pre-glow period Tpg (step S107). Next, the glow plug control unit 15F4 determines whether the pre-glow period Tpg is greater than "0" (step S108). If the pre-glow period Tpg is greater than "0" (step S108: YES), the glow plug control unit 15F4 turns on the glow plug 111 (step S109), starts the pre-glow period Tpg (starts timing) (step S110), and ends the processing shown in FIG. 9. On the other hand, if the pre-glow period Tpg is not greater than "0" (step S108: NO), the starter control unit 15F5 turns on the starter 113 (step S111), and ends the processing shown in FIG. 9.

[0037] (3) Example of operation after time t1 and before time t2 in FIG. 3: When the process shown in FIG. 9 starts, the starter control unit 15F5 determines whether the starter 113 is on or not (step S101). If the starter 113 is not on (step S101: NO), the glow plug control unit 15F4 determines whether the glow plug 111 is on or not (step S102). If the glow plug 111 is on (step S102: YES), the glow plug control unit 15F4 determines whether the pre-glow period Tpg has elapsed or not (step S112). If the pre-glow period Tpg has not elapsed (step S112: NO), the glow plug control unit 15F4 ends the process shown in FIG. 9.

[0038] (4) Example of operation when the pre-glow period Tpg has elapsed (at time t2 in FIG. 3): When the process shown in FIG. 9 starts, the starter control unit 15F5 determines whether the starter 113 is on or not (step S101). If the starter 113 is not on (step S101: NO), the glow plug control unit 15F4 determines whether the glow plug 111 is on or not (step S102). If the glow plug 111 is on (step S102: YES), the glow plug control unit 15F4 determines whether the pre-glow period Tpg has elapsed or not (step S112). If the pre-glow period Tpg has elapsed (step S112: YES), the glow plug control unit 15F4 ends the pre-glow period Tpg (ends timing) (step S113). Next, the starter control unit 15F5 turns on the starter 113 (step S111), and the process shown in FIG. 9 ends.

[0039] (5) Example of operation after time t2 and before time t3 in FIG. 3: When the process shown in FIG. 9 starts, starter control unit 15F5 determines whether starter 113 is on or not (step S101). If starter 113 is on (step S101: YES), starter control unit 15F5 determines whether engine start is successful or not (step S114). If engine start is not successful (step S114: NO), starter control unit 15F5 determines whether the time limit has elapsed or not (step S115). If the time limit has not elapsed (step S115: NO), starter control unit 15F5 ends the process shown in FIG. 9. On the other hand, if the time limit has elapsed (step S115: NO), the glow plug control unit 15F4 turns off the glow plug 111 (step S119), the prohibition period setting unit 15F6 sets the pre-glow prohibition period Tb and starts (starts timing) the pre-glow prohibition period Tb (step S120), the starter control unit 15F5 turns off the starter 113 (step S121), and the process proceeds to the processing when the time limit has elapsed shown in FIG. 10 (step S122).

[0040] (6) Example of operation when engine start is successful (at time t3 in FIG. 3): When the process shown in FIG. 9 is started, the starter control unit 15F5 determines whether the starter 113 is on or not (step S101). If the starter 113 is on (step S101: YES), the starter control unit 15F5 determines whether engine start is successful or not (step S114). If engine start is successful (step S114: YES), the glow plug control unit 15F4 turns off the glow plug 111 (step S116), the prohibition period setting unit 15F6 sets a pre-glow prohibition period Tb and starts (starts timing) the pre-glow prohibition period Tb (step S117), the starter control unit 15F5 turns off the starter 113 (step S118), and the process shown in FIG. 9 ends.

[0041] (7) Operation example when the start instruction issuing unit 15F2 issues a start instruction during the pre-glow prohibition period Tb (after time t3 and before time t4 in FIG. 3): When the processing shown in FIG. 9 starts, the starter control unit 15F5 determines whether the starter 113 is on or not (step S101). If the starter 113 is not on (step S101: NO), the glow plug control unit 15F4 determines whether the glow plug 111 is on or not (step S102). If the glow plug 111 is not on (step S102: NO), the glow plug control unit 15F4 determines whether a start instruction is present or not (step S103). If a start instruction is present (step S103: YES), the glow plug control unit 15F4 determines whether the pre-glow prohibition period Tb is in progress or not (step S104). If it is during the pre-glow inhibit period Tb (step S104: YES), the starter control unit 15F5 turns on the starter 113 (step S111), and the process shown in FIG. 9 ends.

[0042] (8) Processing when time limit has elapsed (processing shown in FIG. 10): When the processing shown in FIG. 10 starts, the restart control unit 15F7 determines whether the restart condition is met (step S201). If the restart condition is met (step S201: YES), the restart control unit 15F7 reissues the start instruction (or causes the start instruction issuing unit 15F2 to reissue) (step S202), and ends the processing shown in FIG. 10. On the other hand, if the restart condition is not met (step S201: NO), the restart control unit 15F7 executes processing for engine start failure (step S203), and ends the processing shown in FIG. 10. The processing for engine start failure is, for example, processing such as notifying the user of the failure.

[0043] (9) Processing shown in Fig. 11: When the processing shown in Fig. 11 is started, the prohibition period setting unit 15F6 determines whether or not it is in the pre-glow prohibition period Tb (step S301). If it is in the pre-glow prohibition period Tb (step S301: YES), the prohibition period setting unit 15F6 determines whether or not the pre-glow prohibition period Tb has elapsed (step S302). If the pre-glow prohibition period Tb has elapsed (step S302: YES), the prohibition period setting unit 15F6 ends the pre-glow prohibition period Tb (step S303) and ends the processing shown in Fig. 11. If it is not in the pre-glow prohibition period Tb (step S301: NO), or if the pre-glow prohibition period Tb has not elapsed (step S302: NO), the prohibition period setting unit 15F6 ends the processing shown in Fig. 11.

[0044] (Variant) In the operation example shown in FIG. 9, the start of the pre-glow prohibition period Tb (step S117 or step S120) is executed before the starter 113 is turned off (step S118 or step S121), but the order of steps S117 and S118 and steps S120 and S121 may be reversed so that the pre-glow prohibition period Tb starts after the starter 113 is turned off.

[0045] (Action and effect) The control board 15 (control device) and transport refrigeration device 1 configured as described above include an acquisition unit 15F1 that acquires information indicating the terminal voltage of the starting battery 14 of the diesel engine 11, a pre-glow period calculation unit 15F3 that calculates a pre-glow period Tpg, which is the time from when the glow plug 111 that heats the combustion chamber of the diesel engine 11 starts to operate until the start of driving of the starter 113 of the diesel engine 11, based on the terminal voltage of the battery 14, a glow plug control unit 15F4 that turns on the glow plug 111 at the start of the pre-glow period Tpg and turns off the glow plug 111 when the diesel engine 11 is successfully started, and a prohibition period setting unit 15F6 that sets a pre-glow prohibition period Tb, which is a period during which the glow plug 111 is prohibited from being turned on after it is turned off. The glow plug control unit 15F4 does not turn on the glow plug 111 during the pre-glow prohibition period Tb. This configuration makes it possible to prevent repeated energization with short de-energized intervals, thereby appropriately controlling energization of the glow plug 111. Furthermore, according to this embodiment, the number of times the glow plug 111 is energized can be reduced and excessive temperature rise can be prevented, thereby extending the life of the glow plug 111 and improving the reliability of the transport refrigeration system 1.

[0046] The acquisition unit 15F1 acquires information indicating the coolant temperature of the diesel engine 11, and the pre-glow period calculation unit 15F3 can calculate the pre-glow period Tpg based on the terminal voltage and the coolant temperature. According to this configuration, the pre-glow period Tpg can be adjusted based on the terminal voltage and the coolant temperature, so that the current supply to the glow plug 111 can be appropriately controlled.

[0047] Furthermore, the pre-glow period calculation unit 15F3 sets the pre-glow period Tpg to zero when the coolant temperature is equal to or higher than a predetermined temperature Twa. According to this configuration, unnecessary pre-glow can be omitted, and therefore, the current supply to the glow plug 111 can be appropriately controlled.

[0048] In this embodiment, the diesel engine 11 is a power source for the refrigerator 12 (one example of the configuration of the "refrigeration device" of the present disclosure).

[0049] The transport refrigeration unit 1 also includes a control board 15 (control device), a diesel engine 11, and a refrigerator 12 (refrigeration unit) that operates using the diesel engine 11 as a power source.

[0050] Moreover, the control method according to this embodiment includes a step (S105) of acquiring information representing the terminal voltage of a starting battery of the engine, a step (S107) of calculating, based on the terminal voltage, a pre-glow period, which is the time from when the glow plug that heats the combustion chamber of the engine starts to operate until the start of driving the engine starter, a step (S109) of turning on the glow plug at the start of the pre-glow period, a step (S116) of turning off the glow plug when the engine is successfully started, and a step (S117) of setting a prohibition period, which is a period during which turning on of the glow plug is prohibited after the glow plug is turned off, and in the step (S109) of turning on the glow plug at the start of the pre-glow period, the glow plug is not turned on during the prohibition period (step S109 is not executed in the flow after step S104: YES).

[0051] Second Embodiment In low-temperature environments, chemical changes in batteries such as lead-acid batteries slow down, increasing their internal resistance. Additionally, as batteries age, they tend to become power-inefficient, preventing the starter from turning and worsening engine starting. Therefore, in the second embodiment, when the outside temperature is low, the glow plugs are turned off during cranking, and power is allocated to turning the starter. The low outside temperature determination is based on the outside air temperature detected by the outside temperature sensor of the refrigerator 12, the coolant temperature of the diesel engine 11 detected by the temperature sensor 112 of the diesel engine 11, or the like (for example, one or both of these).

[0052] Fig. 12 is a diagram showing an example of an engine start sequence according to the second embodiment of the present disclosure. Figs. 13 and 14 are flowcharts showing an example of the operation of the transport refrigeration system 1 according to the second embodiment of the present disclosure. In the first embodiment, as shown by the dashed line in Fig. 12, the glow plugs 111 are turned off when the diesel engine 11 is successfully started (at time t3), whereas in the second embodiment, as shown by the solid line, the glow plugs 111 are controlled to be turned off at the end of the pre-glow period Tpg (at time t2). With this configuration, the current consumed during cranking (from time t2 to time t3) does not include the current consumption ΔI by the glow plugs 111, and therefore the current consumption during cranking (the sum of the current consumption of the starter 113 and the glow plugs 111) can be kept low.

[0053] In the process of the second embodiment shown in FIG. 13, the processes of steps S401 to S402 shown in FIG. 14 are added after the process of step S113. The flows shown in FIG. 13 and FIG. 14 are connected to each other by connectors C1 and C2. In the process shown in FIG. 14, the glow plug control unit 15F4 of the second embodiment determines whether or not a predetermined temperature (the engine coolant temperature or the temperature detected by the external temperature sensor of the refrigerator 12) is below a predetermined low temperature threshold (step S401). If the predetermined temperature is below the predetermined low temperature threshold (step S401: YES), the glow plug control unit 15F4 turns off the glow plug 111 (step S402), and the process proceeds to step S111 (FIG. 13). If the predetermined temperature is not below the predetermined low temperature threshold (step S401: NO), the process proceeds to step S111 (FIG. 13). It should be noted that when the glow plug 111 is turned off in step S402, the glow plug 111 remains in the turned off state in step S116 or step S119 which is executed thereafter.

[0054] <Other embodiments> Although the embodiments of the present disclosure have been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like are also included within the scope of the gist of the present disclosure. For example, in the configuration shown in Fig. 1, AC / DC converter 16 is provided at the output of generator 13, but generator 13 may be replaced by a generator (alternator) capable of outputting DC power, and AC / DC converter 16 may be omitted. Furthermore, compressor 121 may be driven by diesel engine 11 as a compressor without electric motor M1.

[0055] <Computer configuration> FIG. 15 is a schematic block diagram illustrating the configuration of a computer according to at least one embodiment. The computer 90 includes a processor 91 , a main memory 92 , a storage 93 , and an interface 94 . The above-mentioned control board 15 (control device) is implemented in a computer 90. The operations of the above-mentioned processing units are stored in the form of a program in a storage 93. A processor 91 reads the program from the storage 93, loads it into a main memory 92, and executes the above-mentioned processing in accordance with the program. The processor 91 also allocates storage areas in the main memory 92 corresponding to the above-mentioned storage units in accordance with the program.

[0056] The program may be for realizing some of the functions to be performed by the computer 90. For example, the program may be combined with other programs already stored in storage or other programs implemented in other devices to perform the functions. In other embodiments, the computer may include a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device) in addition to or instead of the above configuration. Examples of PLDs include PAL (Programmable Array Logic), GAL (Generic Array Logic), CPLD (Complex Programmable Logic Device), and FPGA (Field Programmable Gate Array). In this case, some or all of the functions realized by the processor may be realized by the integrated circuit.

[0057] Examples of storage 93 include a hard disk drive (HDD), a solid state drive (SSD), a magnetic disk, a magneto-optical disk, a compact disc read-only memory (CD-ROM), a digital versatile disc read-only memory (DVD-ROM), and a semiconductor memory. Storage 93 may be an internal medium directly connected to the bus of computer 90, or an external medium connected to computer 90 via interface 94 or a communication line. Furthermore, when this program is distributed to computer 90 via a communication line, computer 90 that receives the program may load the program into main memory 92 and execute the above-described processing. In at least one embodiment, storage 93 is a non-transitory tangible storage medium.

[0058] <Additional Notes> The control board 15 (control device) and transport refrigeration unit 1 described in each embodiment can be understood, for example, as follows.

[0059] (1) A control device according to a first aspect includes an acquisition unit that acquires information indicating a terminal voltage of a starting battery of an engine, a pre-glow period calculation unit that calculates a pre-glow period, which is a time period from when a glow plug that heats a combustion chamber of the engine starts to be driven until when a starter of the engine starts to be driven, based on the terminal voltage, a glow plug control unit that turns on the glow plug at the start of the pre-glow period and turns off the glow plug when the engine is successfully started, and a prohibition period setting unit that sets a prohibition period, which is a period during which turning on the glow plug is prohibited after the glow plug is turned off, and the glow plug control unit does not turn on the glow plug during the prohibition period. According to this aspect and each of the following aspects, it is possible to appropriately control the supply of electricity to the glow plug.

[0060] (2) A control device according to a second aspect is a control device according to (1), wherein the acquisition unit acquires information representing the engine coolant temperature, and the pre-glow period calculation unit calculates the pre-glow period based on the terminal voltage and the coolant temperature.

[0061] (3) A control device according to a third aspect is the control device of (1) or (2), wherein the pre-glow period calculation unit sets the pre-glow period to zero when the cooling water temperature is equal to or higher than a predetermined temperature.

[0062] (4) A control device according to a fourth aspect is the control device of (1) to (3), wherein the glow plug control unit turns off the glow plug at the end of the pre-glow period when the predetermined temperature is equal to or lower than a predetermined temperature threshold. Note that the predetermined temperature may be any temperature at which it is possible to recognize that the starting battery is in a predetermined low temperature state, and may be, for example, at least one of the ambient temperature of the starting battery, the temperature detected by a sensor for detecting the temperature of the battery provided in the starting battery, the outside air temperature, and the engine coolant temperature.

[0063] (5) A control device according to a fifth aspect is the control device according to any one of (1) to (4), wherein the engine is a power source for the refrigeration device.

[0064] (6) A transport refrigeration unit according to a sixth aspect includes the control device of (1) to (5), the engine, and a refrigeration unit that operates using the engine as a power source. [Explanation of symbols]

[0065] 1...Transportation refrigeration equipment 11...Diesel engine 12...Freezer 13...Generator 14...Battery 15...Control board 15F1…Acquisition part 15F2...Start instruction issuing department 15F3…Pre-glow period calculation section 15F4...Glow plug control unit 15F5...Starter control unit 15F6…Prohibition period setting section 15F7...Restart control section

Claims

1. an acquisition unit that acquires information representing a terminal voltage of a starting battery for the engine; a pre-glow period calculation unit that calculates a pre-glow period, which is a time period from when a glow plug that heats a combustion chamber of the engine starts to when a starter of the engine starts to be driven, based on the terminal voltage; a glow plug control unit that turns on the glow plug at the start of the pre-glow period and turns off the glow plug when the engine has been successfully started; a prohibition period setting unit that sets a prohibition period during which the glow plug is prohibited from being turned on after the glow plug is turned off; Equipped with The glow plug control unit does not turn on the glow plug during the prohibited period. Control device.

2. the acquisition unit acquires information representing a coolant temperature of the engine; The pre-glow period calculation unit calculates the pre-glow period based on the terminal voltage and the coolant temperature. The control device according to claim 1 .

3. The pre-glow period calculation unit sets the pre-glow period to zero when the cooling water temperature is equal to or higher than a predetermined temperature. The control device according to claim 2 .

4. The glow plug control unit turns off the glow plug at the end of the pre-glow period when the predetermined temperature is equal to or lower than a predetermined temperature threshold. The control device according to claim 3 .

5. The engine is a power source for the refrigeration device. The control device according to claim 4.

6. The control device according to any one of claims 1 to 5; the engine; a refrigeration device that operates using the engine as a power source; A transport refrigeration device comprising:

7. obtaining information representing a terminal voltage of a starting battery of the engine; calculating a pre-glow period, which is a time period from when a glow plug for heating a combustion chamber of the engine starts to when a starter of the engine starts to be driven, based on the terminal voltage; turning on the glow plug at the start of the pre-glow period; turning off the glow plug when the engine has successfully started; setting a prohibition period during which the glow plug is prohibited from being turned on after the glow plug is turned off; Including, In the step of turning on the glow plug at the start of the pre-glow period, the glow plug is not turned on during the prohibited period. Control method.

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