JP2009121275A - Electric power supply method to glow plug and vehicular power supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric power supply method to a glow plug, capable of securing minimum glow preheating necessary for start of a diesel engine in accordance with the deterioration degree and remaining capacity of an on-vehicle battery and enabling starter drive. <P>SOLUTION: In this electric power supply method to the glow plug for preheating the diesel engine, each time the diesel engine is started (S3), before the glow plug is energized (S3), the voltage value of the on-vehicle battery is detected as an open circuit voltage value (S1). After the glow plug is energized and temperature rise is completed (S5), a value of voltage after temperature rise and electric current value of the on-vehicle battery are detected (S7), and based on the detected electric current value, value of voltage after temperature rise and open circuit voltage value, a minimum voltage value of the on-vehicle battery when the starter is driven is predicted (S9, 11). When it is determined that the predicted minimum voltage value is a predetermined voltage value or lower (S13), energizing of the glow plug during drive of the starter is restricted or stopped (S19). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a glow plug that preheats a diesel engine from an in-vehicle battery that is charged by an in-vehicle generator linked to the diesel engine, and a power supply method to a glow plug that supplies power to a starter that starts the diesel engine, and The present invention relates to a vehicle power supply device.

Since the diesel engine installed in the vehicle cannot be started by itself, it is equipped with a starter (electric motor) for starting, and the glow plug protruding from the combustion chamber is energized to preheat above the combustible temperature of the fuel. After that, it starts with a starter.
The rapid temperature rise type glow plug, at the start of temperature rise, applies DC12V (in-vehicle battery voltage) and flows a large current to rapidly raise the temperature. After the temperature rises to the target temperature, The rated voltage defined by the plug (usually about DC 4-7V) is maintained to prevent overheating.

For this reason, rapid temperature rise type glow plugs may overheat due to energization exceeding the rated voltage, resulting in disconnection. Therefore, control such as limiting the energization time during preheating is required, and preheating is also required. After completion of (temperature increase), it is necessary to control the temperature by voltage limitation or the like.
The energization of the glow plug is controlled by using the heater resistance value of the glow plug corresponding to the target temperature as an index, based on the energization time determined in advance according to the temperature state or the vehicle battery voltage value. Further, even when the voltage of the in-vehicle battery is lowered, the specified input power (temperature increase performance) is maintained and the glow plug is controlled to be heated to a predetermined target temperature.

Patent Document 1 includes a pre-glow priority unit that waits for the energization control by the pre-glow unit to end and then shifts to the energization control by the cranking glow unit even if the key switch is switched to the start position during the pre-glow. A glow plug control device is disclosed in which the temperature of the engine is rapidly increased to reliably start the engine.
In Patent Document 2, the duty ratio of the voltage waveform applied to the glow plug is calculated based on the voltage value applied from the battery to the glow plug following the energization control by the pre-glow means, and this duty ratio is applied to the glow plug. There is disclosed a glow plug energization control device provided with transition glow means for PWM-controlling the energization of the current. As a result, the temperature of the resistance heater is prevented from dropping after the pre-glow step is completed, and the engine startability is improved.
Japanese Patent Laid-Open No. 2004-232906 Japanese Patent Laid-Open No. 2004-232907

Since the diesel engine is not started when preheating by glow energization is started, the on-vehicle generator (alternator) is stopped, and a current of about several tens to 100 A is supplied from the on-vehicle battery to the glow plug. At the starter start time, as shown in FIG. 3, a starter current (inrush current) of several hundred amperes (for example, 858 A) flows instantaneously through the starter.
Therefore, when the engine is started, a voltage drop due to glow energization occurs, and as shown in FIG. 3, a voltage drop (for example, 7.1 V) due to starter start occurs. It will be done. Therefore, depending on the deterioration level (SOH; State Of Health) and remaining capacity (SOC; State Of Charge) of the vehicle-mounted battery, the battery voltage may drop to a level at which starter drive and cranking operation cannot be maintained, and the engine may not start. There's a problem.

In addition, conventionally, glow energization time adjustment (extension) is performed in order to compensate for a temperature increase rate decrease and a temperature decrease due to a voltage drop during starter driving, so that the amount of power supplied from the in-vehicle battery increases, There was a problem that the voltage drop progressed, the starter drive and cranking operation could not be performed normally, and the engine could not be started.
The present invention has been made in view of the circumstances as described above, and in the first invention, the minimum glow preheating necessary for starting the diesel engine can be secured according to the deterioration degree and remaining capacity of the on-vehicle battery, It is an object of the present invention to provide a power supply method to a glow plug that enables starter driving.
In the second and third inventions, an object of the present invention is to provide a vehicle power supply device that can ensure the minimum glow preheating necessary for starting a diesel engine according to the deterioration degree and remaining capacity of a vehicle-mounted battery and that enables starter driving. And

  According to a first aspect of the present invention, there is provided a method for supplying power to a glow plug, wherein a glow plug for preheating the diesel engine and the diesel engine are started from an in-vehicle battery charged by electric power generated by an in-vehicle generator linked to the diesel engine. In the method of supplying power to a glow plug for supplying power to a starter, each time the diesel engine is started, before energizing the glow plug, the voltage value of the in-vehicle battery is detected as an open voltage value, and the glow plug After the temperature rise is completed, the voltage value after the temperature rise of the in-vehicle battery is detected, and when the voltage value after the temperature rise is detected, the current value of the in-vehicle battery is detected, and the detected current value Based on the post-temperature rise voltage value and the open circuit voltage value, the minimum voltage value of the in-vehicle battery at the time of driving the starter is predicted. It is determined whether or not the predicted minimum voltage value is equal to or lower than a predetermined voltage value. When it is determined that the predicted minimum voltage value is equal to or lower than the predetermined voltage value, energization to the glow plug is restricted or stopped when the starter is driven. Features.

  A vehicle power supply device according to a second aspect of the invention includes an in-vehicle generator that generates power in conjunction with a diesel engine, an in-vehicle battery that is charged with electric power generated by the in-vehicle generator and supplies electric power to a plurality of electric loads, A glow plug that preheats the diesel engine, and a vehicle power supply that supplies power from the vehicle battery to a starter that starts the diesel engine. Each time when the glow plug is started, a means for acquiring the voltage value detected by the voltage detecting means as an open voltage value before energizing the glow plug, and the voltage detecting means after energizing the glow plug and finishing the temperature rise. Means for acquiring the post-temperature increase voltage value detected by the vehicle, and when the means acquires the post-temperature increase voltage value, the on-vehicle battery Means for detecting a current value; means for predicting a minimum voltage value of the in-vehicle battery when the starter is driven based on the current value detected by the means, the voltage value after the temperature increase, and the open-circuit voltage value; Means for determining whether or not the predicted minimum voltage value is less than or equal to a predetermined voltage value, and restricts energization to the glow plug when the starter is driven when it is determined that the means is less than or equal to the predetermined voltage value Or a limiting means for stopping.

  In the power supply method to the glow plug according to the first invention and the vehicle power supply device according to the second invention, the in-vehicle battery is charged by the in-vehicle generator that generates power in conjunction with the diesel engine, and power is supplied to a plurality of electric loads. Supply. Electric power is supplied from a vehicle-mounted battery to a glow plug for preheating the diesel engine and a starter for starting the diesel engine. Each time the diesel engine is started, the voltage value detected by the voltage detecting means is acquired as the open voltage value before the glow plug is energized. After the glow plug is energized and the temperature rise is completed, the post-temperature rise voltage value detected by the voltage detecting means is acquired, and the current value of the in-vehicle battery is detected when the post-temperature rise voltage value is obtained. Based on the detected current value, the voltage value after the temperature rise, and the open circuit voltage value, the minimum voltage value of the on-vehicle battery at the time of driving the starter is predicted, and it is determined whether or not the predicted minimum voltage value is equal to or less than the predetermined voltage value. . When it is determined that the voltage is not more than the predetermined voltage value, the energization to the glow plug is limited or stopped when the starter is driven.

  The vehicle power supply device according to a third aspect of the invention is characterized in that the restriction means is configured to intermittently energize the glow plug when the starter is driven.

  According to the method for supplying power to the glow plug according to the first aspect of the invention, the minimum pre-heating required for starting the diesel engine can be ensured according to the deterioration degree and the remaining capacity of the in-vehicle battery, and starter drive is possible. A power supply method to the glow plug can be realized.

  According to the vehicle power supply device of the second and third aspects of the invention, it is possible to ensure the minimum preheating by the glow plug necessary for starting the diesel engine according to the deterioration degree and the remaining capacity of the in-vehicle battery and to enable the starter drive. A vehicle power supply device can be realized.

Hereinafter, the present invention will be described with reference to the drawings illustrating embodiments thereof.
FIG. 1 is a block diagram showing a main configuration of an embodiment of a method for supplying power to a glow plug and a power supply device for a vehicle according to the present invention.
In this vehicle power supply device, an alternator (on-vehicle generator, AC generator) 1 generates power in conjunction with a diesel engine 3. The generated voltage is controlled at a constant voltage by the regulator 2 attached to the alternator 1 adjusting the field current of the alternator 1.

  The electric power generated by the alternator 1 is rectified in the alternator 1 and then charged to the in-vehicle battery 4 and supplied to an electric load in the vehicle. The voltage detection means 5 in a power control ECU (Electronic Control Unit) 12 detects and acquires the voltage value of the in-vehicle battery 4, and the current detector 13 detects the input / output current of the in-vehicle battery 4 and detects it. The signal is given to the power supply control ECU 12. An on / off signal of the starter switch 16 is given to the power control ECU 12.

The output voltage of the in-vehicle battery 4 is applied to an electrical load such as the seat heater 9 and the air conditioner 10 via the accessory switch 11, and is also applied to the starter 15 that is turned on / off by the starter switch 16.
The output voltage of the in-vehicle battery 4 is also applied to the glow control unit 7 via the preheating switch 8, and the voltage controlled by the glow control unit 7 protrudes from a precombustion chamber (not shown) of the diesel engine 3. It is applied to the glow plug 6 (shown separately in FIG. 1). The on / off signal of the preheating switch 8 is given to the power supply control ECU 12.

  When the preheating switch 8 is turned on, the glow control unit 7 applies the voltage of the in-vehicle battery 4 to the glow plug 6 to rapidly increase the temperature by a large current, and the glow plug 6 is targeted by the heater resistance value of the glow plug 6. When it is detected that the temperature has been reached, a notification signal is given to the power supply control ECU 12. In addition to notifying the driver with an unillustrated indicator lamp, the voltage applied to the glow plug 6 is maintained at the rated voltage defined by the glow plug 6 to prevent overheating, and the power supply control ECU 12 When the instruction signal is given, the voltage applied to the glow plug 6 is controlled according to the instruction signal.

FIG. 2 is a block diagram showing a circuit configuration of the in-vehicle battery 4, the glow control unit 7, the glow plug 6, and the starter 15 (however, switches are omitted). The open-circuit voltage value of the in-vehicle battery 4 is VO, the internal resistance value is Rb, the resistance value including the cable portion of the glow control unit 7 and the glow plug 6 is Rg, and the resistance value including the cable portion of the starter is Rs.
Before the preheating is started when the voltage of the in-vehicle battery 4 is applied to the glow plug 6, the input / output current of the in-vehicle battery 4 is set to 0 (ignoring dark current), and the voltage detected by the voltage detection means 5 is The open-circuit voltage value of the battery 4 can be set. The open-circuit voltage value of the in-vehicle battery 4 has a substantially linear relationship with the remaining capacity of the in-vehicle battery 4, and the remaining capacity can be obtained from the open-circuit voltage value.

If the voltage Vg and current Ig of the in-vehicle battery 4 when the applied voltage is maintained at the rated voltage specified by the glow plug 6 after the glow plug 6 is heated to the target temperature, the in-vehicle battery 4 The internal resistance value Rb is
Rb = (VO−Vg) / Ig (1)
Can be obtained.
Even when the same glow current Ig flows, when the remaining capacity is small and the degree of deterioration is high, the internal resistance value Rb is large, so that the voltage Vg of the in-vehicle battery 4 is low, and even if the remaining capacity is the same, The voltage relationship of the in-vehicle battery 4 is as shown in FIG. Here, SOH = ((full charge capacity at the time of deterioration (Ah)) / (initial full charge capacity (Ah))) × 100%.

If the internal resistance value Rb of the in-vehicle battery 4 is obtained and the resistance values Rg and Rs are known, the voltage drop ΔV (voltage drop) at the start of the starter 15 is
ΔV = VO · Rb / (Rb + Rg · Rs / (Rg + Rs)) (2)
Can be obtained.
The starting current and voltage drop of the starter 15 are as shown in FIG. 3, for example.
After the glow plug 6 is heated to the target temperature, the voltage Vg of the in-vehicle battery 4 when the applied voltage is maintained at the rated voltage defined by the glow plug 6, and the voltage drop Δ when the starter 15 is started The relationship with V (drop voltage) is as shown in FIG. 5 (however, it rises and falls according to the open circuit voltage value VO).

In the present embodiment, the voltage drop ΔV (voltage drop) at the start of the starter 15 is predicted by calculation based on the obtained open circuit voltage value VO and internal resistance value Rb as described above. Further, the voltage drop ΔV (voltage drop) when the open circuit voltage value VO and the internal resistance value Rb are obtained in advance is obtained by actual measurement or calculation, and recorded as a table in the memory 14 in the power supply control ECU 12 for reference. You may make it do.
If the voltage drop ΔV (voltage drop) at the start of the starter 15 can be predicted, the minimum voltage value of the in-vehicle battery 4 at that time can be calculated and predicted by VO−ΔV.

The operation of the vehicular power supply apparatus having such a configuration will be described below with reference to the flowchart shown in FIG.
First, the power supply control ECU 12 reads the voltage value V of the in-vehicle battery 4 detected by the voltage detection means 5, and stores and updates it as the open voltage value VO (S1). Next, it is determined whether or not the preheating switch 8 is turned on (S3). If the preheating switch 8 is not turned on, the voltage value V of the in-vehicle battery 4 detected by the voltage detection means 5 is read and stored as an open voltage value VO. Update (S1).

If the preheating switch 8 is turned on (S3), the power control ECU 12 waits for a signal from the glow control unit 7 to notify that the glow plug has been sufficiently preheated and has reached the target temperature ( S5) When a signal to be notified is given, the voltage value Vg and current value Ig of the vehicle-mounted battery 4 at that time are read (S7).
Next, the power supply control ECU 12 predicts the voltage drop ΔV at the start of the starter 15 from the expressions (1) and (2) (S9), and then calculates VO−ΔV to start the starter 15 at the start. Is predicted (S11).

Next, the power supply control ECU 12 determines whether or not the predicted minimum voltage value Vs is equal to or less than a predetermined voltage value (S13). The predetermined voltage value is determined based on the voltage value of the in-vehicle battery 4 that can normally drive and crank the starter 15 and start the engine.
If the minimum voltage value Vs is equal to or less than the predetermined voltage value (S13), the power supply control ECU 12 waits for the starter switch 16 to turn on (S17), and then restricts the energization of the glow plug 6 to the glow control unit 7 After starting (S19), the starter 15 is started (S21). Next, the process waits until the starter switch 16 is turned off (S23), and the process ends.

When the power supply control ECU 12 restricts the energization of the glow plug 6 to the glow control unit 7 (S19), the power supply control ECU 12 stops the energization of the glow plug 6 or allows the PWM-controlled pulse current to flow (intermittently). ). Further, the difference between the minimum voltage value Vs and the predetermined voltage value (S13) may be calculated, and the conduction current may be subjected to PWM control according to the calculated difference.
If the minimum voltage value Vs is not less than the predetermined voltage value (S13), the power supply control ECU 12 waits for the starter switch 16 to turn on (S15), starts the starter 15 (S21), and then starts the starter switch. Waiting for 16 to turn off (S23), the process ends.

It is a block diagram which shows the principal part structure of embodiment of the electric power supply method to the glow plug which concerns on this invention, and the power supply device for vehicles. It is a block diagram which shows the circuit structure of a vehicle-mounted battery, a glow control part, a glow plug, and a starter. It is a wave form diagram which shows the example of the starting current at the time of starter start, and a voltage drop. It is a characteristic view which shows the relationship between the glow current and the voltage of the vehicle battery. It is a characteristic view which shows the relationship between the voltage of the vehicle-mounted battery at the time of glow plug energization, and the voltage drop at the time of start of a starter. It is a flowchart which shows the operation example of the power supply device for vehicles which concerns on this invention.

Explanation of symbols

1 Alternator (on-vehicle generator, AC generator)
3 Diesel engine 4 On-board battery 5 Voltage detection means 6 Glow plug 7 Glow control unit (limitation means)
8 Preheating switch 12 Power control ECU (voltage detecting means, predicting means, judging means, limiting means)
13 Current detector 14 Memory 15 Starter 16 Starter switch

Claims (3)

A power supply method to a glow plug for preheating the diesel engine and a glow plug for supplying power to a starter for starting the diesel engine from an on-vehicle battery charged by power generated by an on-vehicle generator linked to the diesel engine In
Each time the diesel engine is started, before the glow plug is energized, the voltage value of the in-vehicle battery is detected as an open-circuit voltage value. When the post-voltage value is detected and the post-temperature rise voltage value is detected, the current value of the in-vehicle battery is detected, and based on the detected current value, the post-temperature rise voltage value, and the open-circuit voltage value, the starter Predicting the minimum voltage value of the in-vehicle battery at the time of driving, determining whether or not the predicted minimum voltage value is less than or equal to a predetermined voltage value, A method for supplying power to a glow plug, wherein energization to the glow plug is limited or stopped during driving. An in-vehicle generator that generates power in conjunction with a diesel engine, an in-vehicle battery that is charged with electric power generated by the in-vehicle generator and supplies electric power to a plurality of electric loads, and a voltage detection means that detects a voltage value of the in-vehicle battery In a vehicle power supply device that supplies power from the in-vehicle battery to a glow plug that preheats the diesel engine, and a starter that starts the diesel engine,
Each time the diesel engine is started, before energizing the glow plug, means for acquiring the voltage value detected by the voltage detection means as an open voltage value, and after energizing the glow plug and raising the temperature, Means for acquiring a voltage value after temperature increase detected by the voltage detection means; means for detecting a current value of the in-vehicle battery when the means acquires a voltage value after temperature increase; and a current value detected by the means , Means for predicting the minimum voltage value of the on-vehicle battery when the starter is driven based on the post-temperature rise voltage value and the open circuit voltage value, and whether the minimum voltage value predicted by the means is equal to or less than a predetermined voltage value And a limiting means for limiting or stopping energization to the glow plug when the starter is driven when it is determined that the means is below a predetermined voltage value. Use power supply.   The vehicular power supply apparatus according to claim 2, wherein the limiting means is configured to intermittently energize the glow plug when the starter is driven.

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