JP2013106509A - Decelerating energy regenerative system for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a regenerative function work in a light load region during constant speed travel in a gently declining slope road, in mounting a decelerating energy regenerative system later on a vehicle originally used without mounting the regenerative system.SOLUTION: The decelerating energy regenerative system 1 for controlling a bidirectional DC-DC converter 14 by a signal from an output of a G sensor 10, can be mounted on the vehicle. When the signal from the output of the G sensor 10 is a deceleration direction larger than 0 m/s, a standby battery means 16 is charged. Regenerative operation can be performed, and fuel consumption can be improved, at an engine 2a load, in which the vehicle speed is maintained by operating an accelerator pedal with minute power, during travel in the gently declining slope road.

Description

  The present invention uses the vehicle kinetic energy at the time of deceleration to regenerate the power generated by the vehicle generator to the reserve power storage means, and supplies power to the vehicle electrical load from the reserve power storage means at times other than at the time of deceleration. A deceleration energy regeneration system that improves fuel efficiency by reducing the amount of power generated by the vehicle generator when it is not decelerating, especially by minimizing the number of wiring connections between the deceleration energy regeneration system and the vehicle. The present invention relates to a deceleration energy regeneration system for a vehicle, which can be easily mounted on a vehicle.

  This type of technology includes a vehicle power source including a vehicle generator driven by a traveling engine and main power storage means, a backup power storage means, and a bidirectional connection between the vehicle power supply and the backup power storage means. A DC-DC converter that can be switched and connected in both directions, and can detect the running state of the vehicle by means of an electronic arithmetic unit and charge the reserve power storage means when decelerating. It is known to switch and control the DC-DC converter so that the charged power is discharged with priority over the main power storage means and supplied to the vehicle electrical load.

  Further, the electronic arithmetic unit inputs an idling, acceleration, constant speed running, deceleration, engine stop, or fuel cut signal to the signal receiving terminal, and whether or not the vehicle is decelerating from the input signal. It is discriminated (see Patent Document 1).

  More specific deceleration state detection means include an acceleration sensor (hereinafter referred to as G sensor), a vehicle speed sensor (vehicle speed differential value), a brake pedal stroke sensor, a pedaling force sensor, a brake fluid pressure sensor, and the like (patent) Reference 2).

  Furthermore, the deceleration state of the vehicle can be detected based on the vehicle speed, throttle opening degree, and brake on / off detection results (see Patent Document 3).

  In addition, a technique is disclosed in which acceleration / deceleration is detected from the number of rotations of a generator mounted on a vehicle, and the set value of the generated voltage is changed according to the state of the acceleration / deceleration (Patent Document 4). reference).

  On the other hand, as an additional concept, in addition to the deceleration state detection means described above, a concept is disclosed in which a downhill road existing on a preceding road is identified using a navigation system and power regeneration is actively performed on the downhill road (Patent Document 5). reference).

JP-A-6-296332 JP 2010-104086 A Japanese Patent Application Laid-Open No. 7-310566 JP-A-11-252997 JP 2011-116223 A

  Considering global environmental problems and energy consumption problems in recent years, the improvement of vehicle fuel efficiency is an important technology not only for newly developed and produced new models, but also for measures in use process vehicles that are already on the market. It is a problem.

  Therefore, one aspect of the problem is that the conventional technology disclosed in Patent Documents 1 to 3 is used in retrofitting such a regeneration system in a use process vehicle that is not equipped with a vehicle deceleration energy regeneration system that is significant for improving fuel efficiency. According to the above, in order to determine the deceleration state of the vehicle, wiring means such as an idling switch, a fuel cut signal, a vehicle speed sensor, a brake pedal stroke sensor, a pedaling force sensor, and a brake fluid pressure sensor are required. This is a difficult point.

  According to the prior art disclosed in Patent Document 4, although the wiring means is unnecessary, a dedicated generator with a rotation speed detection function is required, and the cost of the deceleration energy regeneration system including the dedicated generator is reduced. There is a problem of increasing.

  Another aspect of the problem is to improve the regeneration efficiency of the deceleration energy regeneration system of the vehicle. That is, all of the prior arts disclosed in any of Patent Documents 1 to 4 regenerate vehicle kinetic energy as electric power only when the vehicle is decelerated.

  However, on the assumption that the vehicle travels on a gentle downhill road, the vehicle speed may decrease due to engine power loss caused by a known pumping loss or the like when the engine throttle valve is fully closed, that is, when the foot is released from the accelerator pedal. is there. In such a case, the driver gives a small operation amount to the accelerator pedal to maintain the vehicle speed.

In that case, the idling switch is not ON. Further, since the engine needs to continue combustion, the fuel cut does not occur. Furthermore, the brake pedal is not operated. In addition, the vehicle speed has not decreased.
Accordingly, since the state is not distinguished from the above deceleration state from these states, the kinetic energy of the vehicle is not regenerated.

  On the other hand, theoretically, if the regenerative action is applied when traveling at a constant speed on the gentle downhill road, the vehicle speed decreases due to the negative torque of the engine due to the regenerative action. It is thought that the vehicle speed cannot be maintained.

  However, when the vehicle is traveling on the gentle downhill road at a constant speed in an actual road environment, the driver generally operates the accelerator pedal even when the road surface gradient slightly increases downward. The vehicle speed is increased by not following the change of the gradient. At that moment, each factor for determining the deceleration is “not decelerating”. In addition, although the vehicle speed is in the acceleration direction, the vehicle regenerates the kinetic energy of the vehicle by using the regenerative action. At the same time, it is desirable to suppress the increasing vehicle speed.

  As described above, in the determination of the activation / stop of the regeneration function, the driver's accelerator operation with respect to the change in the road surface gradient cannot be the theoretical optimum operation. Therefore, the operation of the regeneration function can be performed only by the conventional deceleration state determination means. The deceleration energy of the vehicle cannot be regenerated efficiently by optimizing the above.

Therefore, as a new concept, there is one that positively activates the regeneration system on downhill roads by identifying the road surface gradient as disclosed in Patent Document 5.
According to this technology, even if there is a slight difference in the amount of accelerator pedal operation by the driver compared to the ideal throttle opening value that can maintain the vehicle speed, the engine load is small as a whole on a downhill road. Since the regenerative operation can be made to work positively in a wide driving range, the deceleration energy regeneration range of the vehicle widens, which is advantageous for improving fuel efficiency.

  However, the regenerative operation should be stopped when the driver performs an intentional acceleration operation even on a downhill. However, it is desirable to control the operation of the regenerative system based not only on the road surface gradient but also on many control factors such as the traveling speed of the vehicle, the accelerator operation amount, the engine speed, and the like.

  However, in order to perform regenerative control based on such many control factors, it is necessary to cooperate with the navigation system and collect various sensor information, so the connection wiring between the vehicle and the deceleration energy regeneration system increases. In addition, since a large-scale control device using a microprocessor or the like is necessary, there is a problem in that it is difficult to mount on the in-use vehicle and the cost is increased.

  Therefore, it is conceivable to use the G sensor mounted on the vehicle to operate the deceleration energy regeneration system when the output signal of the G sensor is in the deceleration direction of the vehicle. That is, since the G sensor outputs a signal in the same direction as that when decelerating due to gravitational acceleration even on a downward slope on a downhill road, the regeneration system can be controlled according to the road surface slope without using the navigation system.

  However, since the output of the G sensor when the vehicle is stopped on a downgraded road surface continues to output a signal in the same direction as the deceleration state due to the gravitational acceleration, the regeneration system is in spite of the vehicle being stopped. The problem that will work will occur. Conversely, when the vehicle is traveling on an uphill road, the G sensor output outputs a signal in the same direction as that during acceleration in accordance with the gravitational acceleration of the uphill road. Even when shifting to slow deceleration by braking, there is a problem that the regenerative system does not operate because the G sensor output is not in the deceleration direction.

  As a means for solving such a problem, a technique is known in which a G sensor signal and a wheel speed sensor signal are combined to separate and calculate a vehicle traveling direction acceleration and a road surface gradient. However, in order to realize this, wiring means is required between the vehicle and a large-scale control device using a microprocessor or the like is required. There is a problem of inviting.

  The invention of the present application has been devised in view of the problems as described above, and can be installed in a process-use vehicle by simply connecting an existing main storage battery and a deceleration energy regeneration device, and includes the gentle downhill road described above. It is an object of the present invention to provide a vehicle deceleration energy regeneration system capable of actively regenerating deceleration energy in a minute engine load region in a running state of the vehicle with a simple configuration and at a low price.

In order to achieve the above object, according to the invention described in claim 1, a vehicle power source including a vehicle generator driven by a traveling engine and a main power storage unit, a reserve power storage unit, and the vehicle power source are provided. And a bidirectional DC-DC converter connected between the auxiliary power storage means, a G sensor for detecting deceleration in the traveling direction of the vehicle, an output signal of the G sensor, and an average traveling speed of the vehicle A high-pass filter with a frequency close to the road gradient change period per unit time as a cutoff frequency, and whether the output signal of the high-pass filter outputs a signal in a deceleration direction greater than 0 m / s ^{2 of the} G sensor A deceleration detecting means for detecting the charge, and the reserve power storage means is charged when the deceleration detecting means detects a deceleration, and the charged electric power is used at times other than when the deceleration is detected. And a control means for controlling the bidirectional DC-DC converter so as to discharge and supply the vehicle electrical load with priority over the main power storage means, and a vehicle deceleration energy regeneration system is proposed. Is done.

  According to a second aspect of the present invention, in addition to the structure of the first aspect, the cutoff frequency of the high pass filter is 0.0001 Hz to 0.01 Hz.

According to a third aspect of the present invention, in addition to the configuration of the first aspect or the second aspect, the deceleration detection means has a deceleration threshold value for determining deceleration of 0.1 m / s ^2. To 0.5 m / s ² .

  According to the invention described in claim 4, in addition to the configuration described in any one of claims 1 to 3, the control means includes a voltage value of the main power storage means and a voltage value of the reserve power storage means. The bidirectional DC-DC converter is configured to stop the operation of charging the reserve power storage means when the difference voltage between the two becomes a predetermined value or less.

  According to the invention described in claim 5, in addition to the configuration described in any one of claims 1 to 3, the control means is configured such that the voltage value of the reserve power storage means becomes a predetermined value or less. In addition, the bidirectional DC-DC converter is configured to stop the operation of discharging the reserve power storage means.

According to the invention described in claim 6, in addition to the configuration described in any one of claims 1 to 5, the control means is configured such that the output signal of the high-pass filter is based on 0 m / s ^{2 of the} G sensor. The charge / discharge current of the reserve power storage means is controlled in proportion to the signal generated through the low-pass filter from the output signal of the deceleration detection means for detecting whether or not a large deceleration direction signal is output. It is characterized by that.

  According to the above configuration, the backup power storage unit, the bidirectional DC-DC converter, the G sensor, the high-pass filter, the deceleration detection unit, and the control unit are configured integrally. Such a deceleration energy regeneration system can be easily mounted on an in-use vehicle simply by connecting to a vehicle battery.

According to the vehicle deceleration energy regeneration system of claim 1, the deceleration detection means detects from the G sensor output that the signal passing through the high-pass filter is a deceleration direction greater than 0 m / s ² and decelerates. Since the reserve power storage means is charged in accordance with the deceleration detection, the minute engine load in which the driver maintains a vehicle speed by giving a minute operation amount to the accelerator pedal when traveling on the gentle downhill road. Even in the case of the region, the G sensor can detect the deceleration equivalently by the magnitude of the gravitational acceleration according to the descending slope of the downhill road, so that the reserve power storage means is charged and the kinetic energy of the vehicle is regenerated. .

In addition, immediately after the vehicle reaches an ascending slope from a flat road while the vehicle is traveling, the acceleration in the traveling direction of the vehicle decreases due to the traveling load due to the road surface gradient, and deceleration acceleration is generated. However, since the G sensor simultaneously receives acceleration in an acceleration direction smaller than 0 m / s ² equivalently depending on the magnitude of gravitational acceleration in the upward gradient, the deceleration detection means does not detect deceleration but depends on the traveling load. The regenerative system does not operate accidentally due to a decrease in vehicle speed.

In addition, since the high-pass filter is provided for the output of the G sensor, when the vehicle stops on a downhill road, the G sensor output signal indicates a predetermined deceleration state corresponding to the gravitational acceleration. Since the high-pass filter output signal becomes equivalent to 0 m / s ² after a predetermined time, the regenerative operation is stopped, and the electric power charged in the reserve power storage means is discharged with priority over the main power storage means and supplied to the vehicle electrical load. As a result, the load on the vehicular generator is reduced and fuel efficiency is improved.

In addition, since the high-pass filter is provided for the output of the G sensor, the G sensor output is accelerated according to the gravitational acceleration of the upward gradient when the vehicle continuously travels on the upward gradient road for a predetermined period. The high-pass filter output signal is equivalent to 0 m / s ² after a predetermined time even though a signal in the same direction as the time is being output, so that the deceleration detection is performed when the vehicle slowly decelerates while traveling uphill. The means can promptly detect deceleration and charge the reserve power storage means to regenerate the kinetic energy of the vehicle.

  According to the vehicle deceleration energy regeneration system of claim 2, the cutoff frequency of the high-pass filter is a frequency close to a road gradient change period per unit time at an average traveling speed of the vehicle. The deceleration detection signal detected by the deceleration detection means is used for the deceleration continuation time when the vehicle is traveling on a flat road and the downhill road continuation time encountered during traveling. It is possible to obtain a deceleration detection time sufficient to charge the reserve power storage means.

According to the vehicle deceleration energy regeneration system of claim 3, the deceleration detection means has a deceleration acceleration threshold value for determining vehicle deceleration from 0.1 m / s ² to 0.5 m / s ^2. Even when the vehicle travels at a constant speed on a gentle downhill road with a slight downward slope from the flat road, it can be reliably detected as a downhill road, and at the same time, erroneously decelerates when traveling on the flat road at a constant speed Is not detected.

  In addition, according to the vehicle deceleration energy regeneration system according to claims 4 and 5, since unnecessary operation of the bidirectional DC-DC converter is prevented, the deceleration energy regeneration system is directly connected to the vehicle battery. Even if connected, the bidirectional DC-DC converter current is not consumed as a dark current while the vehicle is stopped, so that problems such as battery exhaustion do not occur.

According to the vehicle deceleration energy regeneration system according to claim 6, the deceleration for detecting whether or not the output signal of the high-pass filter outputs a signal in a deceleration direction larger than 0 m / s ^{2 of the} G sensor. Since the charge / discharge current of the reserve power storage means is controlled in proportion to the signal generated from the output signal of the detection means via the low-pass filter, the vertical vibration generated during traveling on a flat road of the vehicle causes the Since the control current of the bidirectional DC-DC converter does not change suddenly even when the output signal of the deceleration detection means is turned ON / OFF in a short time, there is a problem of voltage fluctuation of the main power storage means of the vehicle and generation of power supply noise. Absent.

It is a figure showing typically the deceleration energy regeneration system of vehicles concerning one embodiment of the present invention. In the deceleration energy regeneration system of the vehicle concerning one embodiment of the present invention, it is a figure showing the control mode when vehicles run on a flat road. In the deceleration energy regeneration system of the vehicle concerning one embodiment of the present invention, it is a figure showing the control mode when a vehicle shifts from a flat road to a downhill road. In the deceleration energy regeneration system of the vehicle concerning one embodiment of the present invention, it is a figure showing the control mode when a vehicle stops on a downhill road. In the deceleration energy regeneration system of the vehicle concerning one embodiment of the present invention, it is a figure showing the control mode when a vehicle shifts from a flat road to an uphill road. It is a figure which shows the implementation aspect of the deceleration detection means of the deceleration energy regeneration system of the vehicle which concerns on one Embodiment of this invention. It is a figure which shows the implementation aspect of the control means and bidirectional | two-way DC-DC converter of the deceleration energy regeneration system of the vehicle which concerns on one Embodiment of this invention. It is a figure which shows the control mode when the vehicle drive | works the uneven road in the deceleration energy regeneration system of the vehicle which concerns on one Embodiment of invention.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram schematically showing a vehicle deceleration energy regeneration system according to the present invention, wherein 1 is a vehicle deceleration energy regeneration system according to the present invention, 2 is a vehicle generator 2b driven by a traveling engine, and A power source for the vehicle including the main power storage means 2c, 10 is a G sensor that is incorporated in the deceleration energy regeneration system 1 of the vehicle and detects the deceleration of the vehicle. The G sensor 10 is connected to the constant voltage power supply VDD and the ground VSS. Then, a power supply for operation is supplied, and a deceleration signal is input from the terminal 15 a to the deceleration detection means 15 through a high-pass filter constituted by the capacitor 11, the resistor 12, and the resistor 13. Further, the deceleration detecting means 15 is connected to a constant voltage power supply VDD and a ground VSS and supplied with operating power.

  Next, the output terminal 15b of the deceleration detecting means 15 is connected to the control means 17, and the control means 17 is connected to the main power storage means 2c via the terminal T1 and is connected to the terminal 14b for reserve power storage. The bidirectional DC-DC converter 14 that charges and discharges the means 16 is controlled.

  The vehicle deceleration energy regeneration system 1 is configured to be connected to the ground potential of the main power storage means 2c via a terminal T2.

  As shown in FIG. 6, the deceleration detection means 15 compares the signal 15a from the high-pass filter with the divided potential 153a of the resistor 151 and the resistor 152 obtained by dividing the voltage between the constant voltage power supply VDD and the ground VSS. The comparator 153 is configured, and an output signal of the comparator 153 is output from the terminal 15b.

The divided potential 153a is set to be equal to the signal output from the G sensor when the vehicle is 0.3 m / s ^{2 in} the deceleration direction.

  As shown in FIG. 7, the details of the control means 17 are received at the output terminal 15b of the deceleration detection means 15 and input to one terminal of the error amplifier 173 through a low-pass filter formed by a resistor 171 and a capacitor 172. It is. The other terminal of the error amplifier 173 receives an output signal of a current detection amplifier 176 that differentially amplifies both ends of a current detection resistor 175 inserted in series with the output terminal of the bidirectional DC-DC converter 14.

  In FIG. 7, the bidirectional DC− is input by inputting the voltage of the terminal 14a connected to the high potential side of the main power storage means 2c and the signal of the terminal 14b connected to the high potential side of the reserve power storage means 16. The DC converter 14 includes drive determination means 174 for controlling operation / stop of drive circuit means 143 (to be described later).

  Next, as shown in FIG. 7, the bidirectional DC-DC converter 14 drives the output signal 141 of a triangular wave oscillation circuit (not shown) and the output signal of the comparator 142 to which the output signal of the error amplifier 173 is inputted. By inputting to the circuit means 143 and driving the transistor group 144 in a complementary manner, one end of the coil 145 is driven by a known PWM, and the current flowing through the current detection resistor 175 is variable in both directions. .

With the above-described configuration, the vehicle deceleration energy regeneration system 1 according to the present invention controls the control when the output signal of the G sensor 10 through the high-pass filter is greater than 0.3 m / s ^{2 in the} vehicle deceleration direction. The means 17 drives the bidirectional DC-DC converter 14 by PWM so that a predetermined current flows from the main power storage means 2c to the standby power storage means 16 to control the kinetic energy of the vehicle. It acts to regenerate to 16.

When the output signal of the G sensor 10 is less than 0.3 m / s ^{2 in} the deceleration direction of the vehicle, the control means 17 drives the bidirectional DC-DC converter 14 by PWM, and the reserve power storage means 16 is controlled to discharge a predetermined current from the main power storage means 2c to the main power storage means 2c, and the electric power charged in the reserve power storage means 16 is discharged in preference to the main power storage means 2c and supplied to the vehicle electrical load. The fuel generator 2b acts to reduce fuel consumption by reducing the load.

  Further, the drive determination means 174 detects the voltage of the main power storage means 2c from the terminal 14a and also detects the voltage of the reserve power storage means 16 from the terminal 14b, and the voltage of the main power storage means 2c and the reserve power storage means 16 When the voltage difference is small, the drive circuit means 143 of the bidirectional DC-DC converter 14 is stopped because the charging voltage of the reserve power storage means 16 is saturated.

In addition, the drive determination means 174 detects the voltage of the reserve power storage means 16 from the terminal 14b, and when the voltage of the reserve power storage means 16 is in a low voltage state close to 0V, the bidirectional DC- The drive circuit means 143 of the DC converter 14 is stopped.
By acting in this way, the drive determining means 174 detects a state where charging / discharging of the reserve power storage means 16 is unnecessary and stops the operation of the bidirectional DC-DC converter 14, so that the deceleration energy of the present invention is reduced. Even if the regenerative system is directly connected to the battery of the vehicle, the operating current of the bidirectional DC-DC converter 14 is not consumed as a dark current while the vehicle is stopped.

  Next, with reference to FIG. 2, the operation mode of the deceleration energy regeneration system of this invention in a vehicle running state is demonstrated. FIG. 2 shows a state where the vehicle is traveling on a flat road with acceleration / deceleration. Section {circle around (1)} is a section where the vehicle is accelerated at a constant speed from the stop state, and the output of the G sensor 10 outputs a predetermined constant voltage in the non-decelerating direction. In this section, the output signal of the high-pass filter (capacitor 11, resistor 12, resistor 13) outputs a voltage waveform that is substantially equal to the output of the G sensor 10, so that the deceleration detection means 15 does not decelerate the vehicle. Determination is made to send a control signal to the control means 17 of the bidirectional DC-DC converter 14 so that a predetermined discharge current flows from the reserve power storage means 16 to the main power storage means 2c.

  The high-pass filter continuously transmits the output signal state of the G sensor 10 to the deceleration detection means 15 during a period when the output state of the G sensor 10 indicates either acceleration or deceleration. Therefore, it is desirable that the cut-off frequency composed of the capacitor 11, the resistor 12, and the resistor 13 is about 0.003 Hz.

When the vehicle shifts to constant speed in section ( ² ), the output signal of the G sensor 10 becomes a voltage value (1/2 VDD) equivalent to 0 m / s ^2, but the output signal of the high-pass filter is In 1 ▼, since the capacitor 11 has accumulated a certain amount of electric charge, the acceleration in the deceleration direction of the vehicle is indicated for a certain time in the falling derivative of the output signal of the G sensor 10, and thereby the deceleration The output signal of the detection means 15 determines that the vehicle is in a decelerating state, and controls the bidirectional DC-DC converter 14 so that a predetermined charging current flows from the main power storage means 2c to the reserve power storage means 16. A control signal is sent to the means 17.

  In this way, immediately after the vehicle has been in the acceleration state for a certain time and immediately after shifting to constant speed, it is determined that the deceleration detection means is decelerating even though the vehicle traveling speed is not in the deceleration state. And acts to regenerate the kinetic energy of the vehicle. This is because, in general, the accelerator operation when the driver makes a transition from acceleration to constant speed is accompanied by an overshoot in the deceleration direction, so the actual engine load is negative during the overshoot period. In many cases, the vehicle speed is hardly reduced by the inertial moment of the vehicle body. In such a case, it is desirable that the vehicle is in a decelerating state and the regeneration function is activated. However, in the deceleration energy regeneration system of the present invention, the regeneration function operates so as to charge the reserve power storage means 16 in the section (2).

  Further, in the constant speed traveling sections of section (3), section (5) and section (7), the output signal of the high-pass filter outputs a voltage waveform substantially equal to the output of the G sensor 10, so that the deceleration detection is performed. The means 15 judges that the vehicle is not decelerated, and sends a control signal to the control means 17 of the bidirectional DC-DC converter 14 so that a predetermined discharge current flows from the reserve power storage means 16 to the main power storage means 2c. Since the electric power that has been sent out and charged to the reserve power storage means 16 is supplied to the vehicle electrical load, fuel efficiency can be improved.

  Further, in the deceleration traveling sections of section (4) and section (6), the output signal of the high-pass filter outputs a voltage waveform substantially equal to the output of the G sensor 10, so that the deceleration detection means 15 causes the vehicle to decelerate. Determining that it is in a state, sending a control signal from the main power storage means 2c to the control means 17 of the bidirectional DC-DC converter 14 so that a predetermined charging current flows to the reserve power storage means 16; Since the reserve power storage means 16 is charged, the deceleration energy of the vehicle is regenerated.

  As described above, in the deceleration energy regeneration system of the present invention, the high-pass filter consisting of a predetermined constant is added to the output signal of the G sensor, so that not only kinetic energy regeneration during vehicle deceleration but also acceleration of the vehicle is achieved with a simple configuration. Since the regenerative operation in the negative engine load region during the accelerator operation overshoot period of the driver immediately after shifting from traveling to constant speed traveling can be automatically performed, the kinetic energy regeneration region of the vehicle is expanded.

Next, FIG. 3 shows a state in which the vehicle shifts from a flat road to traveling on a downhill road. Section (1) is a section where the vehicle is traveling on a flat road, and the output of the G sensor 10 outputs a voltage value (1/2 VDD) equivalent to 0 m / s ² . In this section, the output signal of the high-pass filter (capacitor 11, resistor 12, resistor 13) outputs a voltage waveform that is substantially equal to the output of the G sensor 10, so that the deceleration detection means 15 does not decelerate the vehicle. Judgment is made and a control signal is sent from the reserve power storage means 16 to the control means 17 of the bidirectional DC-DC converter 14 so that a predetermined discharge current flows to the main power storage means 2c.

  When the vehicle shifts to downhill traveling in section (2), the vehicle speed increases as the vehicle traveling load decreases, but the output signal of the G sensor 10 detects the gravitational acceleration according to the road surface gradient and detects the vehicle's speed. Outputs a voltage value equivalent to the deceleration direction. Therefore, the output signal of the high-pass filter indicates the acceleration in the deceleration direction of the vehicle in the section (2), whereby the output signal of the deceleration detection means 15 determines that the vehicle is in a deceleration state, and A control signal is sent from the power storage means 2 c to the control means 17 of the bidirectional DC-DC converter 14 so that a predetermined charging current flows to the reserve power storage means 16.

  Furthermore, in section (2), the vehicle speed decreases and becomes constant due to the driver's accelerator operation. Even during this period, the output signal of the G sensor 10 detects the deceleration accompanying the decrease in the vehicle speed and the gravitational acceleration due to the road surface gradient. Therefore, the output signal of the deceleration detection means 15 determines that the vehicle is in a decelerating state, and the vehicle kinetic energy is regenerated.

The deceleration detection means 15 is set to about 0.3 m / s ^{2 in} order to enable detection of a road surface gradient of about 3% on a general gentle downhill road at a deceleration threshold value for determining deceleration of the vehicle. Is desirable.

  As described above, when the vehicle shifts from flat road traveling to downhill traveling, the G sensor detects the gravitational acceleration due to the road gradient even though the traveling speed of the vehicle is not in a decelerating state. The deceleration detection means 15 determines that the deceleration is equivalent, and acts to regenerate the kinetic energy of the vehicle.

  As described above, the deceleration energy regeneration system of the present invention uses the output signal of the G sensor to determine the deceleration of the vehicle when the G sensor detects the gravitational acceleration on the road slope of the downhill road, and the regeneration system Since it is configured to operate, not only the kinetic energy regeneration during vehicle deceleration but also the road gradient on the downhill road is detected at the same time by simple configuration, so that the vehicle motion in the minute load region of the engine where the vehicle speed is not decelerated. Since energy regeneration can be performed automatically, the kinetic energy regeneration area of the vehicle is expanded.

Next, FIG. 4 shows a state where the vehicle is stopped while traveling on a downhill road. Section {circle around (1)} is a section where the vehicle is traveling on a downhill road. For example, when the vehicle is traveling on a downhill road with a 5% downward slope, the output of the G sensor 10 is 0.5 m / in the deceleration direction of the vehicle. s ² corresponding to output a voltage value. When such a traveling condition continues for a predetermined period, the capacitor 11 of the high-pass filter has a voltage value equivalent to 0.5 m / s ² on the G sensor side of the capacitor 11 and 0 m / s on the resistor 12 / resistor 13 side. The capacitor 11 is charged so as to have a voltage value equivalent to s ² (1 / 2VDD). Therefore, in the section (1), the deceleration detecting means 15 determines that the vehicle is not in a decelerating state, and the bidirectional DC-DC converter so that a predetermined discharge current flows from the reserve power storage means 16 to the main power storage means 2c. A control signal is sent to 14 control means 17.

  Subsequently, in the section {circle around (2)} in which the vehicle stops, the deceleration according to the decrease in the traveling speed of the vehicle acts on the G sensor 10, so that the output voltage of the G sensor 10 changes in the deceleration direction, and When the output voltage of the high-pass filter changes substantially equally in the deceleration direction, the deceleration detection means 15 determines that the vehicle is in a deceleration state, and a vehicle kinetic energy regeneration operation is performed.

When the vehicle is completely stopped in section (3), the output of the G sensor 10 is equal to that when the vehicle is traveling on the downhill road, and a voltage value equivalent to 0.5 m / s ² is output in the deceleration direction of the vehicle. Based on the charging voltage of the capacitor 11, the deceleration detecting means 15 determines that the vehicle is not in a decelerating state, and the bidirectional DC-DC converter so that a predetermined discharge current flows from the reserve power storage means 16 to the main power storage means 2c. A control signal is sent to 14 control means 17 to supply the electric power charged in the reserve power storage means 16 to the vehicle electrical load.

  As described above, since the deceleration energy regeneration system of the present invention has added a high-pass filter consisting of a predetermined constant to the output signal of the G sensor, when the vehicle stops on a downhill road, the deceleration detection means 15 Since it is determined that the vehicle is not decelerating and the discharged power is supplied from the reserve power storage means 16 to the vehicle electrical load, fuel efficiency is improved.

Next, FIG. 5 shows a state in which the vehicle has shifted to uphill traveling while traveling on a flat road. Section {circle around (1)} is a process in which the vehicle accelerates from a stop and travels on a flat road, and the output of the G sensor 10 outputs a voltage value on the non-decelerating side accompanying the acceleration of the vehicle. Since a voltage value (1/2 VDD) corresponding to 0 m / s ² is output during constant speed traveling, the output signal of the high-pass filter outputs an acceleration signal in the non-decelerating direction of the vehicle, thereby the deceleration detection means The output signal 15 determines that the vehicle is in a non-decelerated state, and supplies the electric power discharged from the reserve power storage means 16 to the vehicle electrical load.

  In section {circle around (2)}, the vehicle speed decreases due to an increase in traveling load due to the vehicle approaching the uphill road, but the output signal of the G sensor 10 detects the gravitational acceleration according to the road surface gradient and determines the vehicle deceleration direction. Outputs the voltage value in the reverse direction. Therefore, the output signal of the high-pass filter indicates the acceleration in the non-deceleration direction of the vehicle in the section (2), whereby the output signal of the deceleration detection means 15 determines that the vehicle is not decelerating and Electric power is supplied from the power storage means 16 to the vehicle electrical load.

  In section (3), the output signal of the G sensor 10 detects the acceleration due to the increase in vehicle speed and the gravitational acceleration according to the road gradient, and outputs a voltage value in the direction opposite to the deceleration direction of the vehicle. Therefore, the output signal of the high-pass filter indicates the acceleration in the non-decelerating direction of the vehicle in the section (3), whereby the output signal of the deceleration detecting means 15 determines that the vehicle is not decelerating and Electric power is supplied from the power storage means 16 to the vehicle electrical load.

In section {circle around (3)}, for example, when the vehicle is traveling on an uphill road with an upward gradient of 5% at a constant speed, the output of the G sensor 10 is 0.5 m in the non-deceleration direction of the vehicle according to the gravitational acceleration due to the road surface gradient. A voltage value equivalent to / s ² is output. When such a running condition continues for a predetermined period, the capacitor 11 of the high-pass filter has a voltage value equivalent to 0.5 m / s ² on the G sensor side of the capacitor 11 toward the non-decelerating side, and a resistance 12 / resistance 13 The capacitor 11 is charged so that the side becomes a voltage value (1/2 VDD) corresponding to 0 m / s ² , and the deceleration detection means 15 continues to determine that the vehicle is not in the deceleration state as described above.

Section (4) shows a state where the vehicle is slowly decelerated while traveling on an uphill road. In the previous section (3), for example, when the vehicle is traveling on an uphill road with an ascending slope of 5%, the output of the G sensor 10 outputs a voltage value equivalent to 0.5 m / s ^{2 in} the non-decelerating direction of the vehicle. In addition, the capacitor 11 of the high-pass filter is charged to a voltage value equivalent to 0 m / s ^{2 on} the resistor 12 / resistor 13 side of the capacitor 11. However, when the vehicle slowly decelerates in the section (4), the output voltage of the sensor decreases due to the deceleration in the traveling direction of the vehicle received by the G sensor 10, and the output voltage of the high-pass filter changes substantially equally in the deceleration direction. The deceleration detection means 15 determines that the vehicle is in a decelerating state, and performs a regeneration operation for vehicle kinetic energy.

  As described above, the deceleration energy regeneration system of the present invention adds a high-pass filter consisting of a predetermined constant to the output signal of the G sensor, so that the vehicle is driven by the driver's accelerator operation while the vehicle continues traveling on the uphill road. In the case of slow deceleration, the deceleration detection means 15 determines that the vehicle is in a decelerating state, and the kinetic energy of the vehicle is regenerated to the reserve power storage means 16.

  Next, FIG. 8 shows that when the vehicle is traveling on a flat road with unevenness, the vehicle body tilt angle fluctuations despite the vehicle speed being constant, the lack of acceleration detection direction separation performance by the G sensor structure, or the G against the vehicle body. Due to the deviation of the mounting angle of the sensor 10 from the horizontal plane, the output signal of the G sensor increases or decreases in a short time, so-called chattering, and the low-pass filter (resistance) of the control means 17 from the output signal. 171 and the waveform through the capacitor 172).

  In such a situation, if a signal passing through the high-pass filter from the G sensor output signal is input to the error amplifier as it is, the control current of the bidirectional DC-DC converter changes suddenly, causing fluctuations in engine driving torque and main power storage means. Problems with voltage fluctuations and power supply noise may occur.

  Therefore, as shown in FIG. 8, the sudden change in the control current of the bidirectional DC-DC converter 14 is suppressed by inputting the output signal 15b of the deceleration detecting means 15 to the error amplifier 173 through a low-pass filter. It is possible to prevent problems of fluctuations in driving torque, voltage fluctuations of the main power storage means 2c, and power supply noise.

  As described above, in the deceleration energy regeneration system of the present invention, the high-pass filter composed of a predetermined constant is added to the output signal of the G sensor. It is possible to automatically perform regenerative operation in the negative engine load region during the overshoot period of the driver's accelerator operation immediately after shifting to traveling, and further, by continuing the uphill road and driving the driver Driving energy can be regenerated when the vehicle decelerates slowly. In addition, vehicle kinetic energy can be regenerated in a minute engine load area where the vehicle speed is not decelerating by simultaneously detecting the slope of the downhill road. Therefore, the kinetic energy regeneration area of the vehicle is expanded and fuel efficiency is improved.

  Further, as an effect of the high-pass filter, when the vehicle stops on a downhill road, the deceleration detection means detects the gravitational acceleration due to the downward slope of the road surface, and performs an erroneous regeneration operation by determining that the vehicle is not in a deceleration state. There is nothing.

  In addition, the deceleration energy regeneration system of the present invention is configured to use the output signal of the G sensor to determine the deceleration of the vehicle using the output voltage corresponding to about 3% of the downhill road of the G sensor as a threshold value. Therefore, the kinetic energy regeneration region and the non-regeneration region of the vehicle can be reliably distinguished and detected.

  In addition, the deceleration energy regeneration system of the present invention only needs to connect +/− of the main power storage means (battery) of the vehicle and the system with a pair of electric wires, and can be easily mounted on the in-use vehicle. .

  The G sensor in the present embodiment detects the deceleration in the traveling direction of the vehicle. However, if the G sensor is disposed in an arbitrary direction between the vertical direction and the traveling direction of the vehicle, the gravity sensor The ability to arbitrarily set the ratio of the road surface gradient detection sensitivity corresponding to acceleration to the acceleration detection sensitivity due to changes in vehicle speed in the vehicle traveling direction is a design matter that can be easily analogized by engineers in the relevant area. .

DESCRIPTION OF SYMBOLS 1 Deceleration energy regeneration system 10 G sensor 14 Bidirectional DC-DC converter 141 Output signal 142 of a triangular wave oscillation circuit 142 Comparator 143 Drive circuit means 144 Transistor group 145 Coil 15 Deceleration detection means 153 Comparator 16 Preliminary storage means 17 Control means 173 Error amplifier 174 Drive determination means 175 Current detection resistor 176 Current detection amplifier 2 Vehicle power supply 2a Engine 2b Vehicle generator 2c Main power storage means

Claims (6)

Vehicle power source including a vehicular generator driven by a traveling engine and main power storage means, standby power storage means, a bidirectional DC-DC converter connected between the vehicle power supply and the backup power storage means, and vehicle A high-pass that is connected to a G sensor that detects a deceleration in the traveling direction of the vehicle and an output signal of the G sensor, and has a cutoff frequency that is close to a road gradient change period per unit time at an average traveling speed of the vehicle A filter, deceleration detection means for detecting whether the output signal of the high-pass filter outputs a signal in a deceleration direction larger than 0 m / s ^{2 of the} G sensor, and when the deceleration detection means detects deceleration The spare power storage means is charged, and the charged power is discharged with priority over the main power storage means and supplied to the vehicle electrical load except when deceleration is detected. And a control means for controlling the bidirectional DC-DC converter.   The vehicle deceleration energy regeneration system according to claim 1, wherein a cutoff frequency of the high-pass filter is 0.0001 Hz to 0.01 Hz. The deceleration detection means has a deceleration threshold value for determining deceleration of the vehicle in a range from 0.1 m / s ² to 0.5 m / s ² , according to claim 1. The vehicle's deceleration energy regeneration system.   When the difference voltage between the voltage value of the main power storage means and the voltage value of the reserve power storage means becomes a predetermined value or less, the control means charges the reserve power storage means by the bidirectional DC-DC converter. The deceleration energy regeneration system for a vehicle according to any one of claims 1 to 3, wherein the operation is stopped.   The control unit is configured to stop the operation of the bidirectional DC-DC converter discharging the standby storage unit when a voltage value of the backup storage unit becomes a predetermined value or less. The vehicle deceleration energy regeneration system according to any one of claims 1 to 3.   The control means controls the bidirectional DC-DC converter so as to charge / discharge the reserve power storage means with a current value proportional to a signal through a low-pass filter from an output signal of the deceleration detection means. The vehicle deceleration energy regeneration system according to any one of claims 1 to 5, wherein the vehicle deceleration energy regeneration system is provided.

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