JP2015082889A - Controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To optimize the correction amount of the output from an internal combustion engine, by estimating the exact magnitude of a load due to a generator driven by the internal combustion engine.SOLUTION: A controller for electrifying and exciting the coil of a generator, and adjusting the output from the generator via a regulator for interrupting electrification and stopping excitation of the coil, determines the effective value or effective duty ratio of a current flowing through the coil based on the lengths of the ON time Twhen the regulator electrifies the coil, and the OFF time Twhen the regulator interrupts electrification of the coil, and estimates the magnitude of a load due to the generator by using the effective value or effective duty ratio of that current, thus correcting the output torque of an internal combustion engine.

Description

  The present invention relates to a control device that controls a generator that generates electric power by receiving transmission of rotational torque from an internal combustion engine.

  In general, in a vehicle equipped with an internal combustion engine, a part of the output torque of the internal combustion engine is supplied to a generator to generate electric power, and the generated electric power is supplied to the electrical system of the vehicle, and an in-vehicle battery is charged. ing.

  The IC regulator associated with the generator adjusts the output of the generator so that the terminal voltage of the battery follows the commanded target voltage (see, for example, the following patent document). Specifically, when the battery voltage is lower than the target voltage, the field coil of the generator is energized and excited, and conversely, when the battery voltage is higher than the target voltage, the energization to the coil is cut off and the excitation is stopped. . The generator performs power generation while the field coil is energized, and stops power generation while the field coil is de-energized. The target voltage is commanded from an ECU (Electronic Control Unit) that controls the internal combustion engine and the generator.

  Further, the ECU controls the control DUTY ratio (fDUTY), which is the ratio of the ON time during which the IC regulator energizes the field coil to the OFF time during which the coil is deenergized, and the current generator speed (engine speed). Etc.), the magnitude of the load torque of the generator is estimated, and correction control for increasing the output of the internal combustion engine by that load is performed.

JP 2012-002068 A

  There is a time constant in the energization circuit including the field coil. Therefore, even if the regulator starts energizing the field coil, the field current flowing through the field coil does not immediately rise to the saturation value. Even if the regulator cuts off the power supply to the field coil, the field current does not immediately drop to zero.

  Therefore, there is a discrepancy between the control duty ratio of the switching operation of the regulator and the effective duty ratio of the field current that actually flows through the field coil (percentage of the average value of the field current when the saturation value is 100%). May occur. For example, even if the control DUTY ratio is 50%, the effective DUTY ratio of the field current may be larger or smaller than 50%. Moreover, the difference between the control DUTY ratio and the effective DUTY ratio varies depending on the ON / OFF switching cycle of energization to the field coil and the rotational speed of the generator.

  The amount of power generated by the generator, in other words, the load torque of the generator depends on the magnitude of the magnetic field generated by the field coil, and the magnitude of the magnetic field generated by the field coil depends on the effective value of the field current and hence the effective DUTY ratio. . Nevertheless, so far, the load torque of the generator has been estimated from the control DUTY ratio, and the amount of correction of the output of the internal combustion engine is not necessarily the optimum size. If the correction amount of the output of the internal combustion engine exceeds the load torque of the actual generator, the engine speed will increase and the fuel efficiency will deteriorate. On the other hand, if the correction amount of the output of the internal combustion engine is less than the actual load torque of the generator, the engine speed decreases and becomes unstable, which may cause engine stall.

  An object of the present invention, which has been made by paying attention to the above problems for the first time, is to accurately estimate the magnitude of the load by the generator and optimize the correction amount of the output of the internal combustion engine.

  In the present invention, a control device that controls a generator that generates electric power by receiving transmission of rotational torque from an internal combustion engine, energizes and energizes a coil of the generator, and stops energization by interrupting energization of the coil. The output of the generator is adjusted via a regulator, and the effective current flowing through the coil is determined based on the ON time during which the regulator energizes the coil and the OFF time during which the coil is deenergized. A control device for obtaining a value or an effective DUTY ratio, estimating the load of the generator using the effective value of the current or the effective DUTY ratio, and correcting the output torque of the internal combustion engine is configured.

  According to the present invention, it is possible to accurately estimate the load of the generator, and to optimize the correction amount of the output of the internal combustion engine.

The figure which shows schematic structure of the internal combustion engine in one Embodiment of this invention. The circuit diagram which shows the electric power generation system in the embodiment. The timing diagram which shows transition of the increase of the field current in the period which has supplied with electricity to the field coil. The timing diagram which shows the pattern of the fluctuation | variation of a control signal current and a field current. The figure which illustrates the map which prescribes | regulates the relationship between the effective value or effective DUTY ratio of field current, and engine speed (or generator speed), and the load torque of a generator.

  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 in the present embodiment is a spark ignition type 4-stroke gasoline 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. 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 power generation system mounted on the vehicle will be described. A generator (alternator or motor generator) 110 is connected to a crankshaft of an internal combustion engine via a winding transmission mechanism having a belt and a pulley as elements, and is rotated by the rotation of the crankshaft to generate electric power. Various electric loads for charging electric power to the in-vehicle battery 120 or mounted on the vehicle (illumination lamp, electric power steering device, radiator fan, blower for blower, defogger, audio equipment, car navigation system, etc., not shown) Power to

  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 a switching circuit 131 using a power device (power semiconductor element) represented by a power transistor, a power MOSFET, and the like.

  The voltage control circuit 132 of the regulator 130 receives a signal l for instructing the target voltage of the generator 110 from the ECU 0 serving as a control device, and switches the power device 131 to cause the terminal voltage of the battery 120 to follow the instructed target voltage. Make it work. That is, as shown in FIG. 3, when the battery voltage is lower than the target voltage, the field coil 112 is energized and excited, and when the battery voltage is higher than the target voltage, the current to the coil 112 is cut off. Stop excitation.

  The generator 110 becomes a mechanical load when viewed from the internal combustion engine. When a field current is applied to the field coil 112, the generator 110 spends the energy of rotation of the crankshaft of the internal combustion engine to generate electrical energy. Accordingly, the torque supplied from the crankshaft of the internal combustion engine to the vehicle drive system and thus to the axle is reduced.

  When the field current is not supplied to the field coil 112, the generator 110 does not perform the work of generating electric energy by consuming energy of rotation of the crankshaft. Accordingly, the torque supplied from the crankshaft of the internal combustion engine to the drive system and the axle increases.

  The ECU 0 serving as a control device that controls 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 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 and engine speed of the crankshaft, and depression of an accelerator pedal. The accelerator opening signal c output from a sensor that detects the amount or the opening of the throttle valve 32 as an accelerator opening (so-called required load), the intake air temperature and the intake pressure in the intake passage 3 (particularly, the surge tank 33). The intake air temperature / intake pressure signal d output from the temperature / pressure sensor to be detected, the cooling water temperature signal e output from the water temperature sensor to detect the cooling water temperature of the internal combustion engine, and a plurality of cam angles of the intake camshaft or the exhaust camshaft The cam angle signal f output from the cam angle sensor, the current flowing into and out of the battery 120, and the battery 120 A battery current / voltage signal g output from a sensor for detecting a child voltage, and a signal h indicating a waveform of energization / cutoff of the field current output from the built-in circuit 133 of the regulator 130 (ignition / extinction of the power device 131). Etc. are input.

  From the output interface, 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 a voltage regulator for controlling the output voltage of the generator 110 A voltage command signal l or the like is output to 65.

  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 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, output voltage of the generator 110, etc. Determine various operating parameters. The ECU 0 applies various control signals i, j, k, and l corresponding to the operation parameters via the output interface.

  In order to stabilize the power supply to various electric loads and extend the life of the battery 120, the battery voltage is required to be maintained at a required target voltage, for example, 14.5V. Incidentally, the value of 14.5V is a terminal voltage when the universal vehicle-mounted battery 120 is in a state close to full charge.

  Normally, the ECU 0 gives this target voltage 14.5V to the regulator 130 as a command l. Receiving this, the regulator 130 conducts feedback control to energize the field coil 112 when the battery voltage is less than 14.5V, and to interrupt energization to the field coil 112 when the battery voltage is 14.5V or more. carry out.

While the regulator 130 is energizing the field coil 112, the field current flowing through the field coil 112 increases nonlinearly. When the regulator 130 cuts off the power supply to the field coil 112, the field current decreases non-linearly. FIG. 3 shows a pattern of increasing field current. Assuming that the energization circuit including the field coil 112 is an RL series circuit, the field current I (t) when the DC voltage E is applied to the energization circuit from time t = 0 is
I (t) = {1-e- ^{(R / L) t} } E / R
It is expressed. That is, the field current I gradually increases as a transient phenomenon, but the rate of increase gradually decreases. When a sufficiently long time has elapsed (t increases), the field current I saturates to the saturation value E / R.

The ECU 0 receives from the built-in circuit 133 of the regulator 130 a control signal current h indicating the pattern of the field current switching operation executed by the regulator 130. From this control signal h, the length of the ON time T _ON when the regulator 130 energizes the field coil 112 and the OFF time T _{OFF when} the field coil 112 is de-energized can be measured.

Therefore, the ECU 0 can grasp the control DUTY ratio that is the ratio of the ON time T _ON and the OFF time T _OFF , but the effective DUTY ratio (saturation value) of the field current that actually flows through the field coil 112 can be determined. The percentage of the average value of the field current at 100% does not always coincide with this control DUTY ratio.

  FIG. 4 illustrates respective waveforms of the control signal current h and the field current. As already described, since there is a time constant in the energizing circuit including the field coil 112, the field current does not immediately increase to the saturation value even when the regulator 130 starts energizing the field coil 112. Even if the regulator 130 cuts off the power supply to the field coil 112, the field current does not immediately decrease to zero.

  Therefore, for example, even if the control DUTY ratio (ratio occupied by halftone dots in FIG. 4) is x%, the effective DUTY ratio of field current (ratio occupied by hatched parts in FIG. 4) is greater than x%. Sometimes less than x%. In addition, the difference between the control DUTY ratio and the effective DUTY ratio varies depending on the ON / OFF switching period of energization of the field coil 112 and the rotational speed of the generator 110.

  Therefore, even if an attempt is made to determine the magnitude of the load torque generated by the generator 110 based on the control DUTY ratio, there is a risk of deviating from the actual load torque of the generator 110. If the increase correction of the output torque of the internal combustion engine is performed based on the inaccurate load torque based on the control duty ratio, the output of the internal combustion engine is too large, causing an increase in the engine speed, or the output of the internal combustion engine is increased. If it is too small, the engine speed will drop. This particularly has an adverse effect on the rotation control during idle operation.

Therefore, the ECU 0 of the present embodiment has an ON time T _ON when the regulator 130 energizes the field coil 112 and an OFF time T _OFF when the field coil 112 is de-energized, which is known with reference to the control signal current h. Based on the length, the effective value or effective DUTY ratio of the field current flowing through the field coil 112 is obtained. Then, the magnitude of the load torque by the generator 110 is estimated using the effective value or effective DUTY ratio of the field current, and the output torque of the internal combustion engine is corrected so as to compensate for the load torque.

The time constant (L / R in the above equation) of the energizing circuit including the field coil 112 can be experimentally obtained in advance. The magnitude of the voltage (E in the above equation) applied to the energization circuit is also known. Therefore, the magnitude of the field current flowing through the energization circuit can be defined as a function of time. The ECU 0 can calculate the field current at an arbitrary time by substituting the ON time T _ON and the OFF time T _OFF into the function. Further, the effective value or effective DUTY ratio of the field current can be calculated by integrating the function with time integration or integrating the time series of instantaneous values of the field current obtained by using the function.

  The load torque applied to the internal combustion engine due to the power generation of the generator 110 depends on the effective value or effective DUTY ratio of the field current and the rotation speed of the generator 110. The rotational speed of the generator 110 is proportional to the engine rotational speed. In the memory of the ECU 0, map data that prescribes the relationship between the effective value of field current or effective DUTY ratio, the engine speed, and the load torque of the generator 110 is stored. FIG. 5 illustrates map data. The ECU 0 searches the map using the current effective value or effective DUTY ratio of the field current and the engine speed as a key, and obtains an estimated value of the current load torque of the generator 110.

  Accordingly, the ECU 0 increases the opening degree of the throttle valve 32 according to the obtained load torque magnitude of the generator 110, increases the intake air amount and the fuel injection amount charged into the cylinder 1, and increases the engine torque. Increase.

In the present embodiment, the control device 0 controls the generator 110 that receives the rotational torque from the internal combustion engine and generates power to charge the battery 120, and the generator 110 when the battery voltage is lower than the commanded voltage. The coil 112 is energized and excited, and when the battery voltage is higher than the commanded voltage, the output of the generator 110 is adjusted via a regulator 130 that interrupts the energization to the coil 112 and stops the excitation. Yes, based on the length of the ON time T _ON when the regulator 130 energizes the coil 112 and the OFF time T _{OFF when} the coil 112 is de-energized, the effective value or effective value of the current flowing through the coil 112 is determined. The duty ratio is obtained, the effective value of the current or the effective duty ratio is used to estimate the load of the generator 110, and the internal combustion engine The control apparatus 0 which correct | amends the output torque of this was comprised.

  According to this embodiment, the magnitude of the load by the generator 110 can be accurately estimated, and the output correction amount of the internal combustion engine can be optimized. Therefore, the correction amount of the output of the internal combustion engine does not significantly exceed the actual load torque of the generator 110, which does not cause an increase in the engine speed and contributes to an improvement in fuel efficiency. In addition, the correction amount of the output of the internal combustion engine is not significantly lower than the actual load torque of the generator 110, the rotation of the internal combustion engine is stabilized, and the risk of engine stall is avoided.

  The present invention is not limited to the embodiment described in detail above. For example, the resistance value (R in the above equation) of the energization circuit of the field coil 112 increases as the temperature of the field coil 112 or the energization circuit increases. Therefore, when estimating the load torque of the electric motor 110, it is preferable to correct the effective value or effective DUTY ratio of the field current according to the temperature of the field coil 112, the energizing circuit or the electric motor 110.

  It is also conceivable to reversely calculate the effective value of the field current that causes the output voltage of the generator 110 to follow the target voltage or the control DUTY ratio that realizes the effective DUTY ratio, and to trigger the switching operation in the regulator 130 using the control DUTY ratio.

  Alternatively, the effective value or effective DUTY ratio of the field current so that the load torque of the generator 110 becomes a certain target torque is obtained from the map data, the control DUTY ratio for realizing this is calculated backward, and the regulator 130 is obtained by using the control DUTY ratio. It is also conceivable to cause a switching operation in.

  Other specific configurations of each part can be variously modified without departing from the spirit of the present invention.

  The present invention can be applied to control of an internal combustion engine mounted on a vehicle or the like and a generator attached thereto.

0 ... Control unit (ECU)
110 ... Generator 112 ... Coil (field coil)
130 ... Regulator

Claims (1)

A control device that controls a generator that generates power by receiving transmission of rotational torque from an internal combustion engine,
Energize the coil of the generator to excite it, adjust the output of the generator via a regulator that cuts off the current to the coil and stops excitation,
Based on the ON time during which the regulator energizes the coil and the OFF time during which the coil is de-energized, the effective value or effective DUTY ratio of the current flowing through the coil is obtained, and the effective value of the current is obtained. Or the control apparatus which estimates the magnitude | size of the load by the said generator using an effective DUTY ratio, and correct | amends the output torque of an internal combustion engine.

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