JP4415851B2 - Idle stop vehicle - Google Patents

Description

  The present invention relates to control of supply voltage to electrical components when shifting to an idle stop state in an idle stop vehicle.

Patent Document 1 describes an idle stop vehicle that suppresses fuel consumption by stopping the engine when the vehicle is stopped and restarting the engine when starting.
JP 2001-173481 A

  In the idle stop vehicle, the electric power generated by the alternator is supplied to the electrical component before the engine is stopped, and the electric power stored in the battery is supplied after the stop.

  However, there is a voltage difference between the generated power of the alternator and the discharged power of the battery, and when the idle stop is executed and the engine is stopped, the voltage of the power supplied to the electrical components changes suddenly and the Flickering occurs in lighting or pop sounds are generated on audio equipment.

  An object of the present invention is to suppress the occurrence of flickering of electrical components and pop sound of audio equipment due to a voltage difference at the time of transition to an idle stop state in an idle stop vehicle.

  The present invention lowers the power generation voltage of the generator over a predetermined time, and stops the engine when the power generation voltage of the generator is reduced to the discharge voltage of the battery and a predetermined idle stop permission condition is satisfied. .

  According to the present invention, since the supply voltage to the electrical component can be reduced to the battery discharge voltage before shifting to the idle stop state, the supply voltage to the electrical component is reduced when the idle stop is executed. A sudden decrease can be prevented. Therefore, flickering of lights, lighting, etc. and generation of pop sound in audio can be suppressed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a system configuration diagram showing an idle stop vehicle in the present embodiment.

  The engine 1 generates a driving force that is transmitted to the driving shaft 3 via the transmission 2 and generates a driving force for generating the required power of the electrical component 4 mounted on the vehicle 50. The motor generator 5 is connected to the engine 1 by winding a belt 7 around each pulley 6. A motor generator (MG) (generator) 5 rotates by the driving force of the engine 1 to generate electric power, and transmits the driving force to the engine 1 when the engine is started to perform cranking. The battery 8 stores power generated by the MG 5 and supplies power to the electrical component 4. Note that the electrical component 4 emits light and sound, such as a light, meter, illumination, audio, and navigation system.

  The vehicle speed sensor 9 detects the speed of the vehicle 50 and transmits it to the controller 10. The inhibitor switch 11 detects the mode of the transmission 2 determined by the shift position selected by the driver and transmits it to the controller 10. The accelerator pedal operation amount 12 sensor detects the operation amount of the accelerator pedal by the driver and transmits it to the controller 10. The brake pedal force sensor 13 detects the pedal force of the brake pedal by the driver and transmits it to the controller 10. The engine rotation speed sensor 14 detects the rotation speed of the engine 1 and transmits it to the controller 10. The controller 10 controls the power generation voltage of the MG 5 and the operation of the engine 1 based on the vehicle speed, the transmission mode, the accelerator pedal operation amount, the brake depression force, the engine rotation speed, and the storage state (SOC) of the battery 8.

  Next, control performed by the controller 10 will be described with reference to FIG. FIG. 2 is a flowchart showing the control of the idle stop vehicle in the present embodiment. This control adjusts the timing of the idle stop execution and the supply voltage decrease based on the SOC of the battery 8 when the vehicle 50 shifts to the idle stop state, while keeping the SOC of the battery 8 high. It is intended to suppress flickering of lights and lighting and the occurrence of pop sounds in audio.

  In step S1, it is determined whether the vehicle 50 stops. When it is determined that the vehicle 50 is to be stopped, the process proceeds to step S2, and when it is not determined that the vehicle is to be stopped, the process is ended. In step S1, the stop of the vehicle 50 is predicted, and the accelerator operation amount by the driver is zero, the brake pedal force is at least a predetermined value, the vehicle speed is at a predetermined speed or less, and the engine speed is at least a predetermined speed. When the vehicle is expected to stop.

  In step S2, it is determined whether or not the SOC of the battery 8 is greater than a predetermined value. If the SOC of the battery 8 is greater than the predetermined value, the process proceeds to step S3, and if the SOC is less than the predetermined value, the process proceeds to step S6. The predetermined value is a value such that the battery 8 is almost fully charged.

  In step S3, the power generation voltage of MG5 is reduced at a predetermined rate of change until the discharge voltage of battery 8 is reached. The supply voltage to the electrical component 4 is the power generation voltage (for example, about 14V) of the MG 5 while the engine 1 is operating, that is, when the MG 5 is operating. However, when the engine 1 stops, the MG 5 also stops. It becomes a discharge voltage (for example, about 12.5 V) by electric power.

  Therefore, the generated voltage of MG 5 is reduced to the discharge voltage of battery 8 in order to eliminate the voltage difference before and after the engine 1 is stopped. The predetermined rate of change at this time is a low rate of change that can be suppressed to such an extent that flickering of lights and lighting, pop noise in audio equipment, etc. does not occur, or to the extent that the passenger cannot recognize, and in this embodiment 1.5V / Sec or less is set.

  In step S4, it is determined whether an idle stop permission condition is satisfied. If the idle stop permission condition is satisfied, the process proceeds to step S5, and if not satisfied, the process is terminated. The idle stop permission condition is a state in which the mode of the transmission 2 selected by the driver is in the D range and the vehicle speed is zero.

  In step S5, idle stop is executed. In idling stop, the controller 10 stops fuel injection to stop the engine 1.

  On the other hand, when it is not determined in step S2 that the SOC of the battery 8 is greater than the predetermined value, the process proceeds to step S6, and it is determined whether the idle stop permission condition is satisfied. If the idle stop permission condition is satisfied, the process proceeds to step S7, and if not satisfied, the process is terminated.

  In step S7, the power generation voltage of MG5 is lowered to the discharge voltage of battery 8 at a predetermined rate of change. The predetermined change rate is the same as the change rate used in step S3.

  In step S8, it is determined whether or not the power generation voltage of MG5 is equal to or lower than the discharge voltage of battery 8. If the power generation voltage of MG5 is less than or equal to the discharge voltage of battery 8, the process proceeds to step S5 to execute idle stop, and if greater than the discharge voltage of battery 8, the process ends.

  Next, the operation of this embodiment will be described with reference to FIG. FIG. 3 is a time chart showing the control of the idle stop vehicle in the present embodiment. 3A shows a case where the present invention is not applied, FIG. 3B shows a case where the SOC of the battery 8 is higher than a predetermined value in the present embodiment, and FIG. 3C shows an SOC of the battery 8 in the present embodiment. Is shown when each is below a predetermined value.

  First, for comparison, a case where the present invention is not applied will be described with reference to FIG. Since the engine 1 is in operation, the MG 5 is operating, and the supply voltage to the electrical component 4 is the power generation voltage of the MG 5. When the idle stop permission condition is satisfied at time t2, the idle stop is executed, and MG5 also stops as the engine 1 stops. As a result, the supply voltage to the electrical component 4 rapidly decreases to the discharge voltage of the battery 8, thereby causing flickering in lights, lighting, etc. and popping sound in audio equipment.

  Next, a case where the present invention is applied and the SOC of the battery 8 is higher than a predetermined value will be described with reference to FIG. If the vehicle 50 is predicted to stop at time t1, the power generation voltage of the MG 5 is reduced to the discharge voltage of the battery 8 in preparation for the case where the idle stop permission condition is satisfied. At this time, if the voltage is suddenly lowered, there is a risk of flickering in lights, lighting, etc. and pop sound in the audio equipment, so the voltage is gradually lowered at a predetermined rate of change.

  Thereafter, when the idle stop permission condition is satisfied at time t2, the idle stop is executed. Even if the engine 1 is stopped by executing the idle stop, the supply voltage to the electrical component 4 remains the discharge voltage of the battery 8 and does not change, so that flickering in lights, lighting, etc. and pop sound generation in audio equipment are suppressed. Can do.

  Next, a case where the present invention is applied and the SOC of the battery 8 is not more than a predetermined value will be described with reference to FIG. After the vehicle 50 is predicted to stop at time t1, the voltage of MG5 is not lowered, so the supply voltage to electrical component 4 is the power generation voltage of MG5. The reason why the voltage of MG5 is not lowered is that the SOC of the battery 8 is below a predetermined value, so that the SOC is raised as much as possible before the engine 1 stops.

  Thereafter, even if the idle stop permission condition is satisfied at time t2, idle stop is not executed, and the power generation voltage of MG5 is lowered to the discharge voltage of battery 8. At this time, if the voltage drops rapidly, there is a risk of flickering in lights, lighting, etc. and pop sound in the audio equipment, so the voltage is gradually reduced at a predetermined rate of change. When the power generation voltage of MG5 drops to the discharge voltage of battery 8 at time t3, idle stop is executed and engine 1 is stopped. Thereby, since the supply voltage to the electrical component 4 remains the discharge voltage of the battery 8 and does not change, it is possible to suppress the occurrence of flickering in lights or lighting and the occurrence of pop sounds in audio equipment.

  As described above, in the present embodiment, control is performed so that the engine 1 is stopped by performing idle stop after the supply voltage to the electrical component 4 is lowered from the power generation voltage of the MG 5 to the discharge voltage of the battery 8 over a predetermined time. To do. As a result, it is possible to prevent the supply voltage to the electrical component 4 from abruptly decreasing from the power generation voltage of the MG 5 to the discharge voltage of the battery 8 at the time of transition to the idle stop state. Generation of sound can be suppressed. In addition, since generation of line noise due to fluctuations in the supply voltage can be suppressed, deterioration of audio reproduction sound quality can be suppressed, and the life of the power supply line to the electrical component 4 can be improved.

  Further, since the supply voltage to the electrical component 4 is reduced at a predetermined rate of change from the power generation voltage of the MG 5 to the discharge voltage of the battery 8, the idle stop is performed. It is possible to more reliably prevent the voltage from rapidly decreasing from the power generation voltage of the MG 5 to the discharge voltage of the battery 8.

  Furthermore, by setting the predetermined rate of change to a value of 1.5 V / sec or less, it is possible to suppress flickering of lights, lighting, etc. and pop sound in audio equipment, etc., so that the passenger cannot recognize it, so that more reliably Flickering of lights, lighting, etc., and pop sounds in audio equipment can be suppressed.

  Furthermore, when the vehicle 50 is predicted to stop and the SOC of the battery 8 is higher than a predetermined value, the power generation voltage of the MG 5 is immediately reduced to the discharge voltage of the battery 8, and then the idle stop permission condition is satisfied. When it is established and the engine 1 is stopped, the idle stop can be executed quickly. Therefore, flickering of lights and lighting and generation of pop sounds in audio and the like can be suppressed while improving fuel consumption.

  Furthermore, when the SOC of the battery 8 is equal to or lower than a predetermined value, the power generation voltage of the MG 5 is lowered after the predetermined idle stop permission condition is satisfied, and the power generation voltage of the MG 5 is lowered to the discharge voltage of the battery 8. Since the engine 1 is stopped by executing the idle stop, it is possible to prevent the supply voltage to the electrical component 4 from rapidly decreasing. Therefore, it is possible to suppress flickering of lights, lighting, etc. and generation of pop sound in audio or the like while improving the SOC of the battery 8 as much as possible before shifting to the idle stop state.

  Furthermore, since it is predicted that the vehicle 50 stops when the accelerator operation amount by the driver is zero, the brake pedaling force is equal to or greater than a predetermined value, and the vehicle speed is equal to or lower than the predetermined speed or the engine speed is equal to or lower than the predetermined speed. When the SOC of the battery 8 is high, the stop of the vehicle 50 can be predicted earlier, and the power generation voltage of the MG 5 can be lowered to the discharge voltage of the battery 8 before executing the idle stop. Therefore, it is possible to more reliably suppress the flickering of lights and lighting and the occurrence of pop sounds in audio.

  Although the embodiments of the present invention have been described above, the scope of application of the present invention is not limited to the described embodiments, and various modifications and changes can be made within the scope of the technical idea thereof. It is obvious that they are equivalent.

  For example, although the present embodiment has been described using an idle stop vehicle as shown in FIG. 1, the present invention is not limited to this and may be an idle stop vehicle as shown in FIGS. 4 and 5. In these configurations, the same control as described above is possible.

  The idle stop vehicle shown in FIG. 4 includes a battery 20 having a discharge voltage higher than that of the battery 8 of the present embodiment, and the supply voltage of the battery 20 is reduced by the DC / DC converter 21 before being supplied to the electrical component 4. It has a configuration.

  The idle stop vehicle shown in FIG. 5 includes an alternator 30 and a starter motor 31 instead of the motor generator 5 of the present embodiment. The alternator 30 is connected to the engine 1 and each pulley 32 by a belt 33 and is rotated by the driving force of the engine 1 to generate electric power. The starter motor 31 is connected to the engine 1 via a gear 34, and transmits a driving force to the engine 1 to start cranking when the engine is started. The battery 8 stores the generated voltage of the alternator 30 and supplies power to the starter motor 31 and the electrical component 4.

  Furthermore, the present invention can be applied to all kinds of idle stop vehicles not illustrated here.

  Moreover, although light, audio, etc. were illustrated as an electrical component, it should just emit light and a sound with the electric power supplied from the battery 8, without limiting to this.

It is a system configuration figure showing an idle stop vehicle in this embodiment. It is a flowchart which shows control of the idle stop vehicle in this embodiment. It is a time chart which shows the action | operation of the idle stop vehicle in this embodiment. It is the block diagram which showed the example of the idle stop vehicle which can apply this invention. It is the block diagram which showed another example of the idle stop vehicle which can apply this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 2 Transmission 3 Drive shaft 4 Electrical component 5 Motor generator (MG)
6 pulley 7 belt 8 battery 9 vehicle speed sensor 10 controller 11 inhibitor switch 12 accelerator pedal operation amount sensor 13 brake pedal force sensor 14 engine rotation speed sensor 20 battery 21 DC / DC converter 30 alternator 31 starter motor 32 pulley 33 belt 34 gear 50 vehicle

Claims (8)

Engine,
A generator that generates electric power by rotating by the driving force of the engine;
A battery for storing electric power generated by the generator;
An electrical component that operates by the generated voltage of the generator during operation of the engine and operates by a discharge voltage of the battery when the engine is stopped, and outputs at least one of light and sound;
Voltage control means for reducing the generated voltage of the generator to the discharge voltage of the battery over a predetermined time;
Idle stop control means for stopping the operation of the engine when the power generation voltage of the generator is reduced to the discharge voltage of the battery by the voltage control means and a predetermined idle stop permission condition is satisfied;
An idle stop vehicle comprising:   2. The idle stop vehicle according to claim 1, wherein the voltage control unit reduces the generated voltage of the generator to a discharge voltage of the battery at a predetermined rate of change.   The idle stop vehicle according to claim 2, wherein the predetermined change rate is 1.5 V / sec or less.   When the vehicle is predicted to stop and the battery storage state is higher than a predetermined value, the voltage control means reduces the power generation voltage of the generator before the predetermined idle stop permission condition is satisfied. The idle stop vehicle according to any one of claims 1 to 3, wherein   When the vehicle is predicted to stop and the storage state of the battery is less than or equal to a predetermined value, the voltage control means determines the power generation voltage of the generator after the predetermined idle stop permission condition is satisfied. The idle stop vehicle according to any one of claims 1 to 4, wherein the idle stop vehicle is lowered.   The idle-stop vehicle according to claim 4 or 5, wherein the vehicle is predicted to stop when an accelerator operation amount by a driver is zero, a brake pedaling force satisfies all of a predetermined value or more and a vehicle speed satisfies a predetermined speed or less. .   6. The vehicle is predicted to stop when the accelerator operation amount by the driver is zero, the brake pedal effort satisfies all of a predetermined value or more and the engine rotation speed satisfies a predetermined rotation speed or less. 6. Idle stop vehicle. An engine, a generator that rotates by the driving force of the engine to generate electric power, a battery that stores electric power generated by the generator, and an electrical component that outputs at least one of light and sound toward a passenger In the engine stop method of the idle stop vehicle provided,
Decreasing the power generation voltage of the generator over a predetermined time to the discharge voltage of the battery,
Stopping the operation of the engine when a power generation voltage of the generator is reduced to a discharge voltage of the battery and a predetermined idle stop permission condition is satisfied,
The engine stop method characterized by the above-mentioned.

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