JP2017152283A - Control unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To more accurately determine a liquid temperature in an on-vehicle battery upon restarting of an internal combustion engine that has been turned off.SOLUTION: A control unit estimates a liquid temperature in an on-vehicle battery upon restarting of an internal combustion engine that has been turned off. The control unit regards the least value among the following as the liquid temperature in the battery upon restarting of the internal combustion engine: a liquid temperature indicating the temperature in the internal combustion engine upon restarting of the internal combustion engine; an estimated value of a liquid temperature in the battery at the last time when the internal combustion engine was turned off; and an ambient temperature in the vicinity of the battery upon restarting of the internal combustion engine.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a control device that estimates the liquid temperature of an in-vehicle battery.

  A lead battery widely adopted as a battery for vehicles has an increased internal resistance and a deterioration in charge acceptability when the temperature of the electrolyte, which is a battery solution that fills the inside of the battery, decreases. Therefore, after grasping the current battery liquid temperature, it is necessary to adjust the length of the charging period according to the battery liquid temperature (for example, refer to the following patent document). Otherwise, when the battery liquid temperature is low, there is a concern that the battery is not sufficiently charged and the amount of stored electricity is insufficient, and the life of the battery is shortened due to sulfation.

  Since the battery liquid is strongly acidic, it is difficult to directly measure the liquid temperature by putting a temperature sensor in the battery liquid. Therefore, conventionally, a temperature sensor (thermistor) is arranged near the battery electrode, and the temperature of the battery is estimated by detecting the temperature of the atmosphere near the battery.

  However, the temperature of the atmosphere in the vicinity of the battery detected by the above temperature sensor does not necessarily accurately represent the actual battery liquid temperature. For example, when an internal combustion engine of a vehicle that has been parked for a long time in an environment where the outside air temperature is low is cold-started, for a while after the start-up, the battery liquid temperature is reduced against the rise in the temperature of the atmosphere in the engine room. The rise is delayed, and a divergence occurs between the temperature detected by the temperature sensor and the actual battery liquid temperature. That is, the battery liquid temperature is estimated to be higher than actual.

  Also, when the internal combustion engine that has been operating is stopped and the vehicle is parked for a relatively short time (several tens of hours to about an hour), after the operation of the internal combustion engine is stopped, the engine cooling water is circulated and Since there is no inflow of traveling wind, the atmosphere in the engine room temporarily rises, and accordingly, the temperature detected by the temperature sensor also rises. On the other hand, the battery liquid temperature does not necessarily follow the rise in the temperature of the atmosphere in the engine room. As a result, the temperature detected by the temperature sensor when the internal combustion engine is restarted after parking for a relatively short time may be higher than the actual battery liquid temperature.

JP 07-298507 A

  An object of the present invention is to more accurately grasp the liquid temperature of a vehicle-mounted battery when restarting an internal combustion engine that has been stopped.

  In the present invention, the temperature of the vehicle-mounted battery at the time of restart of the internal combustion engine that has been stopped is estimated, and the temperature of the fluid that indicates the temperature of the internal combustion engine at the time of restart of the internal combustion engine, the latest internal combustion engine Control that regards the estimated value of the battery liquid temperature when the engine is stopped and the temperature of the atmosphere in the vicinity of the battery when the internal combustion engine is restarted as the battery liquid temperature when the internal combustion engine is restarted Configured the device.

  According to the present invention, it is possible to more accurately grasp the liquid temperature of the vehicle-mounted battery when the internal combustion engine that has been stopped is restarted.

The figure which shows schematic structure of the internal combustion engine for vehicles and control apparatus in one Embodiment of this invention. The electric circuit diagram which shows the outline | summary of the electric power generation system of the vehicle in the embodiment. The figure which illustrates transition of the fluctuation | variation of the temperature of the atmosphere of the battery vicinity, and the temperature of a battery liquid in the case of restarting after stopping an internal combustion engine once. The figure which illustrates transition of the fluctuation | variation of the temperature of the atmosphere of the battery vicinity in operation of an internal combustion engine and a vehicle, the temperature of battery liquid, and the estimated value of the temperature of battery liquid.

  An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an outline of an internal combustion engine for a vehicle in the present embodiment. The internal combustion engine of this embodiment is a port injection type four-stroke spark ignition engine, and includes a plurality of cylinders 1 (one of which is shown in FIG. 1). In the vicinity of the intake port of each cylinder 1, an injector 11 for injecting fuel is provided for each cylinder 1. A spark plug 12 is attached to the ceiling of the combustion chamber of each cylinder 1. The spark plug 12 receives spark voltage generated by the ignition coil and causes spark discharge between the center electrode and the ground electrode. The ignition coil is integrally incorporated in a coil case together with an igniter that is a semiconductor switching element.

  The intake passage 3 for supplying intake air takes in air from the outside and guides it to the intake port of each cylinder 1. On the intake passage 3, an air cleaner 31, an electronic throttle valve 32, a surge tank 33, and an intake manifold 34 are arranged in this order from the upstream.

  The exhaust passage 4 for discharging the exhaust guides the exhaust generated as a result of burning the fuel in the cylinder 1 from the exhaust port of each cylinder 1 to the outside. An exhaust manifold 42 and an exhaust purification three-way catalyst 41 are disposed on the exhaust passage 4.

  The EGR (Exhaust Gas Recirculation) device 2 realizes a so-called high pressure loop EGR, and an external EGR passage 21 that communicates the upstream side of the catalyst 41 in the exhaust passage 4 and the downstream side of the throttle valve 32 in the intake passage 3. The EGR cooler 22 provided on the EGR passage 21 and the EGR valve 23 that opens and closes the EGR passage 21 and controls the flow rate of the EGR gas flowing through the EGR passage 21 are used as elements. The inlet of the EGR passage 21 is connected to the exhaust manifold 42 in the exhaust passage 4 or a predetermined location downstream thereof. The outlet of the EGR passage 21 is connected to a predetermined location downstream of the throttle valve 32 in the intake passage 3, particularly to the surge tank 33.

  Various electric loads are mounted on the vehicle. Specific examples thereof include an ignition system for an internal combustion engine, various valves 23 and 32, etc., an illumination lamp (head lamp, tail lamp, fog lamp, turn signal lamp, etc.), a radiator fan for air-cooling engine cooling water, An electric power steering device, an electric motor that rotationally drives the crankshaft when starting the internal combustion engine (starter motor; however, it may be an integrated starter generator (ISG) integrated with the generator 110), and an air conditioner for vehicle interior air conditioning Examples include a blower for shona, a defogger for removing fog from the rear glass, an audio device, and a car navigation system.

  A generator (alternator, which may be an ISG integrated with an electric motor) 110 serving as a source of power supply to an electric load is connected to an internal combustion engine via a winding transmission mechanism having a belt and a pulley as elements. It is connected to a crankshaft that is an output shaft, is driven to rotate by transmission of rotational torque from the crankshaft, and the generated electric power is charged to the in-vehicle battery 120 and / or various electric devices mounted on the vehicle. Supply power to the load. The battery 120 is a well-known lead battery, nickel-metal hydride battery, lithium ion battery, or the like for vehicles. Further, the generator 110 may perform regenerative power generation. That is, when the driver does not step on the accelerator pedal and does not require acceleration of the vehicle (accepts deceleration), the energy of rotation of the crankshaft and axle (drive wheels) is converted into electric energy. The internal combustion engine and the vehicle are decelerated while being collected by the battery 120.

  FIG. 2 shows an equivalent circuit of the power generation system. The generator 110 includes a stator coil 111 wound around a stator, and a field coil 112 wound around a rotor that is disposed inside the stator and rotates. The stator coil 111 is a three-phase coil, and generates a three-phase alternating current. The induced current is stored in the battery 120 after being converted into a direct current by a rectifier 113 using a diode.

  The regulator 130 is of the IC type that is attached to the generator 110 and controls the magnitude of the voltage that the generator 110 generates and outputs. The regulator 130 energizes the field coil 112 via the switching circuit 131 using a semiconductor switching element.

  The voltage control circuit 132 of the regulator 130 receives a signal m for instructing a target voltage of the generator 110 from an ECU (Electronic Control Unit) 0 as a control device, and causes the terminal voltage of the battery 120 to follow the instructed target voltage. PWM (Pulse Width Modulation) control for switching the power device 131 is performed. The output voltage of the generator 110, that is, the voltage induced in the stator coil of the generator 110 increases in proportion to fDUTY, which is the DUTY ratio of the excitation current flowing through the field coil 112. The amount of power generated by the generator 110, in other words, the amount of charge to the battery 120 and / or the amount of power supplied to the electric load increases as fDUTY increases and decreases as fDUTY decreases.

  The generator 110 becomes a mechanical load when viewed from the internal combustion engine. When the output voltage of the generator 110 exceeds the terminal voltage of the battery 120, the battery 120 is charged and electric power is supplied from the generator 110 to the electric load. That is, the generator 110 spends the energy of rotation of the crankshaft to generate electric energy. The amount of charge to the battery 120 and the amount of power supplied to the electric load depend on the potential difference between the output voltage of the generator 110 and the battery 120 voltage.

  Conversely, when the output voltage of the generator 110 is less than the battery 120 voltage or close to the battery 120 voltage, the battery 120 is not charged and no power is supplied from the generator 110 to the electric load (from the battery 120 to the electric load). May be powered). In other words, the generator 110 does not perform work that consumes the energy of rotation of the crankshaft, or the work is reduced.

  In short, when a high output voltage is commanded from the ECU 0 to the regulator 130, the mechanical load of the generator 110 with respect to engine rotation increases, and when a low output voltage is commanded, the mechanical load of the generator 110 with respect to engine rotation decreases.

  The ECU 0 that controls the operation of the internal combustion engine and the generator 110 is a microcomputer system having a processor, a memory, an input interface, an output interface, and the like.

  The input interface of the ECU 0 includes a vehicle speed signal a output from a vehicle speed sensor that detects the actual vehicle speed of the vehicle, a crank angle signal b output from an engine rotation sensor that detects the rotation angle of the crankshaft and the engine speed of the internal combustion engine. , An accelerator opening signal c output from a sensor that detects the amount of depression of the accelerator pedal or the opening of the throttle valve 32 as an accelerator opening (so-called torque required for the internal combustion engine), an intake passage 3 (in particular, a surge tank 33) An intake air temperature / intake pressure signal d output from a temperature / pressure sensor that detects the intake air temperature and intake pressure in the engine, a cooling water temperature signal e output from a water temperature sensor that detects an engine cooling water temperature indicating the temperature of the internal combustion engine, Cam angle signal output from cam angle sensor at multiple cam angles of intake camshaft or exhaust camshaft A battery current / temperature signal g output from a current / temperature sensor (including a thermistor) 140 that detects the current flowing into and out of the battery 120 and the temperature of the atmosphere in the vicinity of the electrode terminal of the battery 120, and a circuit built in the regulator A waveform of energization / cutoff of the excitation current output from 133 (ignition / extinction of the power device 131), and an fDUTY signal h indicating the magnitude of the excitation current are input.

  From the output interface of the ECU 0, an ignition signal i for the igniter of the spark plug 12, a fuel injection signal j for the injector 11, an opening operation signal k for the throttle valve 32, and an opening operation for the EGR valve 23. The voltage command signal m and the like are output to the voltage regulator 130 that controls the signal l and the output voltage of the generator 110.

  The processor of the ECU 0 interprets and executes a program stored in the memory in advance, calculates operation parameters, and controls the operation of the internal combustion engine. The ECU 0 acquires various information a, b, c, d, e, f, g, and h necessary for operation control of the internal combustion engine via the input interface, knows the engine speed, and is filled in the cylinder 1. Estimate the intake volume. Based on the engine speed and the intake air amount, the required fuel injection amount, fuel injection timing (including the number of fuel injections for one combustion), fuel injection pressure, ignition timing, required EGR rate (or EGR amount) ) And various operating parameters such as the output voltage (power generation amount) of the generator 110 are determined. The ECU 0 applies various control signals i, j, k, l and m corresponding to the operation parameters via the output interface.

  Further, the ECU 0 inputs a control signal o for operating the electric motor when the internal combustion engine is started (a cold start or a return from an idling stop). Perform cranking to rotate. Cranking is complete when the internal combustion engine has gone from the first explosion to a continuous explosion and the engine speed, that is, the rotation speed of the crankshaft, exceeds a judgment value determined according to the temperature of the internal combustion engine (cooling water temperature), etc. Ends (assuming something).

  The ECU 0 of the present embodiment estimates the current liquid temperature of the battery 120 with reference to the battery temperature signal g.

First, a method for determining the initial value of the battery fluid temperature when restarting the internal combustion engine that has been stopped (particularly during cold start) will be described. That is, the ECU 0
(A) Engine coolant temperature at the time of restart of the internal combustion engine (B) Estimated value of battery fluid temperature at the time of the most recent stop of the internal combustion engine (C) Temperature of atmosphere near the battery 120 at the time of restart of the internal combustion engine Of these, the one with the smallest value is regarded as the battery fluid temperature when the internal combustion engine is restarted.

  The engine coolant temperature in (A) can be obtained by referring to the coolant temperature signal e. The estimated value of the battery liquid temperature in (B) will be described later. The temperature of the atmosphere in the vicinity of the battery 120 in (C) can be obtained by referring to the battery temperature signal g.

FIG. 3 shows the temperature of the atmosphere in the vicinity of the battery 120 when the operating internal combustion engine is stopped and the vehicle is parked for a relatively short time (several tens to one hour) and then the internal combustion engine is restarted. An example of transition of the fluctuation | variation of the temperature of a battery liquid is shown. In FIG. 3, the chain line represents the temperature of the atmosphere near the battery 120, and the solid line represents the temperature of the battery fluid. After the time point t ₀ when the operation of the internal combustion engine is stopped and the vehicle is parked, the circulation of the engine cooling water and the inflow of the traveling wind into the engine room are eliminated, so that the atmosphere in the engine room temporarily rises. Accordingly, the temperature detected by the temperature sensor 140 installed in the vicinity of the electrode terminal of the battery 120, in other words, the temperature obtained by referring to the battery temperature signal g is also increased. On the other hand, the battery liquid temperature does not necessarily follow the increase in the temperature of the atmosphere in the engine room.

Conventionally, the battery liquid temperature at the restart point t ₁ of the internal combustion engine has been determined exclusively with reference to only the battery temperature signal g. For this reason, the battery liquid temperature recognized by the ECU 0 may deviate from the actual battery liquid temperature. On the other hand, in this embodiment, by setting the lowest one of the above temperature values (A), (B), and (C) as the battery liquid temperature at the restart point t ₁ of the internal combustion engine, The deviation between the battery liquid temperature recognized by the ECU 0 and the actual battery liquid temperature is suppressed.

Subsequently, the estimation of the battery liquid temperature during operation of the internal combustion engine and the vehicle will be described. The ECU 0 according to the present embodiment estimates the current liquid temperature of the battery 120 by performing a time series process of the temperature value of the atmosphere in the vicinity of the battery 120 obtained by sampling the battery temperature signal g every predetermined time. To do. In particular,
y (n) = y (n-1) + {u (n) -y (n-1)} / f (n)
As described above, the temperature value is smoothed by taking a time-series moving average of the temperature value. In the above equation, u (n) is a current sampling value of the battery temperature signal g, y (n) is an estimated value of the current battery fluid temperature obtained as a result of smoothing the sampling value of the battery temperature signal g, y (n−1) is an estimated value of the latest past battery liquid temperature, 1 / f (n) is a coefficient defining the degree of annealing (the strength of the annealing process), and (n) is a discrete time Means the nth sampling value.

  The degree of annealing increases as the coefficient 1 / f (n) increases (in other words, as f (n) decreases). In this embodiment, the smoothing coefficient 1 / f (n) when the vehicle speed is relatively high is compared with the smoothing coefficient 1 / f (n) when the vehicle speed is relatively low. In other words, the smoothing coefficient 1 / f (n) is changed according to the current vehicle speed. Specifically, the coefficient 1 / f (n) when the vehicle speed obtained by referring to the vehicle speed signal a is equal to or higher than a certain threshold (for example, 60 km / h) It is set larger than the coefficient 1 / f (n). Further, in the high vehicle speed range where the vehicle speed is equal to or higher than the threshold value, the coefficient 1 / f (n) is set larger as the vehicle speed becomes higher.

  The reason why the coefficient 1 / f (n) of the annealing process is changed according to the vehicle speed is that the higher the vehicle speed, the greater the amount of heat generated by the internal combustion engine and the greater the amount of traveling wind blown into the engine room. This is based on the fact that the speed of temperature rise of the battery liquid and the speed of temperature drop of the high temperature battery liquid increase.

  FIG. 4 illustrates an estimation result of the battery liquid temperature by the ECU 0 of the present embodiment. In FIG. 4, the chain line represents the time series of the temperature value of the atmosphere near the battery 120 obtained by sampling the battery temperature signal g, and the solid line represents the actual battery liquid temperature. A thick broken line represents the battery liquid temperature estimated (smoothing process) by the method of the present embodiment, and a thin broken line represents a battery in which the coefficient 1 / f (n) of the smoothing process is estimated to be constant regardless of the current vehicle speed. Represents the liquid temperature. As apparent from FIG. 4, the difference between the estimated battery liquid temperature and the actual battery liquid temperature is reduced by changing the smoothing coefficient 1 / f (n) according to the vehicle speed. Can do.

  In the present embodiment, the liquid temperature of the vehicle-mounted battery 120 when the internal combustion engine that has been stopped is restarted is estimated, and a fluid (engine cooling water) that indicates the temperature of the internal combustion engine when the internal combustion engine is restarted is estimated. ), The estimated value of the liquid temperature of the battery 120 at the time of the most recent stop of the internal combustion engine, and the temperature of the atmosphere in the vicinity of the battery 120 at the time of restart of the internal combustion engine. The control device 0 was regarded as the liquid temperature of the battery 120 at the time. According to this embodiment, the liquid temperature of the battery 120 immediately after restarting the internal combustion engine that has been stopped can be grasped more accurately.

  In addition, in the present embodiment, the current liquid temperature of the battery 120 is estimated by performing a time series of temperature values obtained through the sensor 140 that detects the temperature of the atmosphere in the vicinity of the vehicle-mounted battery 120. The control device 0 is configured to increase the degree of annealing when the vehicle speed is high compared to the degree of annealing when the vehicle speed is low. According to this embodiment, the liquid temperature of the battery 120 during operation of the internal combustion engine and the vehicle can be grasped more accurately. As a result, it is possible to optimize the control of the power generation of the generator 110 and the charging of the battery 120, avoiding insufficient charging of the battery 120, extending the life of the battery 120, and improving the fuel efficiency performance by improving the efficiency of power generation and charging. Can contribute.

  The present invention is not limited to the embodiment described in detail above. For example, in the above embodiment, the temperature of the engine cooling water is used to estimate the liquid temperature of the battery 120 when the internal combustion engine is restarted. However, instead of this, the temperature of the engine lubricating oil, the temperature of the hydraulic fluid (transmission fluid (CVTF or ATF)) used in the torque converter or transmission of the drive system that connects the internal combustion engine and the axle (drive wheel). (A) may be used as the temperature of the fluid indicating the temperature of the internal combustion engine.

  In addition, when estimating the liquid temperature of the battery 120 by smoothing the time series of temperature values obtained by sampling the battery temperature signal g, the calculation formula of the filter for the smoothing process and the strength of the smoothing are calculated. The specific method to change is not limited to that of the above embodiment. For example, as another method of changing the annealing intensity, it is conceivable to increase or decrease the number of past temperature values used for taking a moving average. That is, when performing smoothing processing by taking a time-series moving average of a plurality of temperature values sampled in the past, if the vehicle speed is relatively high, a moving average of x temperature values is taken. When the vehicle speed is lower than that, a moving average of y temperature values less than x is taken.

  In addition, the specific configuration of each part, the content of processing, and the like can be variously modified without departing from the spirit of the present invention.

  The present invention can be applied to control of a vehicle equipped with an internal combustion engine, a generator, and a battery.

0 ... Control unit (ECU)
DESCRIPTION OF SYMBOLS 120 ... Battery 140 ... Sensor which detects the temperature of the atmosphere of the battery vicinity g ... Battery temperature signal

Claims (1)

Estimating the liquid temperature of the in-vehicle battery when restarting the internal combustion engine that was stopped,
Of the temperature of the fluid that indicates the temperature of the internal combustion engine when the internal combustion engine is restarted, the estimated value of the liquid temperature of the battery when the internal combustion engine is immediately stopped, and the temperature of the atmosphere near the battery when the internal combustion engine is restarted A control device that regards the smallest value as the battery liquid temperature when the internal combustion engine is restarted.

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