JP2016011635A - Control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the hunting of the idle rotation number of an internal combustion engine in an environment in which atmospheric pressure is low.SOLUTION: A control device for controlling an auxiliary machine which operates by receiving the transmission of rotation torque from an internal combustion engine adjusts an output of a load of the auxiliary machine with respect to the internal combustion engine of the auxiliary machine on the basis of the current engine speed and the atmospheric pressure during the idle operation of the internal combustion engine. By this constitution, surplus engine torque exceeding the torque necessary for maintaining idle rotation is spent for the operation of the auxiliary machine in an environment in which atmospheric pressure is low, and the acceleration of the idle rotation can be suppressed.

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.

  Recently, for the purpose of further improving the fuel consumption performance of a vehicle, reduction of mechanical loss in an internal combustion engine and a drive system mounted on the vehicle has been attempted.

  As a result, the engine torque required to maintain the rotation of the internal combustion engine during idling is decreasing. And in the environment where the atmospheric pressure represented by the high ground is low, the back pressure, that is, the pressure in the exhaust passage may be lowered, and the required torque is further reduced.

  For this reason, in an environment where the atmospheric pressure is low, even though the throttle valve (or the idle speed control valve) is throttled to the lower limit, engine torque more than the necessary torque is output and the idling speed is reduced. It will rise.

  When the idling speed exceeds the target speed, a fuel cut that temporarily interrupts fuel injection will be carried out (see, for example, the following patent document), but even if the idling speed once decreases due to the fuel cut, If fuel injection is restarted, it will be unavoidable that this rises again. Therefore, fuel cuts occur intermittently, causing hunting that repeatedly increases and decreases the idling speed, which may adversely affect drivability.

  The problem of idling speed hunting in a low atmospheric pressure environment is particularly likely to occur during a stop in the N range where the clutch interposed between the crankshaft and the axle of the internal combustion engine is disengaged.

JP 2008-087789A

  An object of the present invention is to suppress hunting of the idling speed in an environment where the atmospheric pressure is low, typified by a high altitude.

  In order to solve the above-described problems, the present invention controls an auxiliary machine that operates by receiving rotational torque from an internal combustion engine, and controls the current engine speed and atmospheric pressure during idle operation of the internal combustion engine. Based on this, a control device for adjusting the load on the internal combustion engine of the auxiliary machine is configured.

  That is, by increasing the load of the auxiliary machine driven by the internal combustion engine in a low atmospheric pressure environment, excessive engine torque exceeding the required torque is consumed for driving the auxiliary machine. With such a configuration, it is possible to suppress acceleration of idle rotation of the internal combustion engine.

  The load of the auxiliary machine increases as the atmospheric pressure decreases in a region where the atmospheric pressure is equal to or higher than a predetermined value, but preferably decreases as the atmospheric pressure decreases in a region where the atmospheric pressure is less than a predetermined value. This is because when the atmospheric pressure is very low, the amount of intake air that fills the cylinders of the internal combustion engine also decreases significantly, making it difficult for the internal combustion engine to output excess engine torque.

  According to the present invention, it is possible to suppress idle speed hunting in an environment where atmospheric pressure is low.

The figure which shows schematic structure of the internal combustion engine and control apparatus in one Embodiment of this invention. The circuit diagram which shows the electric power generation system in the embodiment.

  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 external EGR device 2 realizes a so-called high-pressure loop EGR. The external EGR passage 21 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, and the EGR passage 21. The EGR cooler 22 provided above 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, specifically to a surge tank 33.

  A power generation system mounted on a vehicle will be described. A generator (alternator or motor generator) 110 is connected to a crankshaft which is an output shaft 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. Then, the generated electric power is charged into the in-vehicle battery 120, or various electric loads (illumination lamp, electric power steering device, radiator fan, blower for blower, defogger, audio device, car navigation system, etc.) mounted on the vehicle. (Not shown).

  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. PWM (Pulse Width Modulation) control to operate 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. Accordingly, the engine torque supplied from the crankshaft of the internal combustion engine to the drive system of the vehicle and thus to the axle (drive wheel) is reduced. 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. Accordingly, the engine torque supplied from the crankshaft of the internal combustion engine to the drive system and the axle increases.

  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 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). From an intake air temperature / intake pressure signal d output from a temperature / pressure sensor to be detected, a coolant temperature signal e output from a water temperature sensor to detect a coolant temperature suggesting the temperature of the internal combustion engine, from an atmospheric pressure sensor to detect atmospheric pressure Is it a sensor that detects the output atmospheric pressure signal f, the current flowing into and out of the battery 120, and the terminal voltage of the battery 120? Battery current and voltage signals g output, signal h for indicating a waveform of the energization / interruption of the field current output from the internal circuit 133 of the regulator 130 (ignition / extinguishing of the power device 131) is 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 1 is output to 65 and an opening operation signal m is output to the EGR valve 32.

  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, the fuel injection timing (including the number of times of fuel injection for one combustion), the fuel injection pressure, the ignition timing, the output voltage of the generator 110, the required Various operation parameters such as an EGR rate (or EGR amount) are determined. The ECU 0 applies various control signals i, j, k, l and m corresponding to the operation parameters via the output interface.

  Thus, the ECU 0 of the present embodiment generates the generator 110 based on the current engine speed and atmospheric pressure when idling when the accelerator pedal depression amount (accelerator opening degree, required load) by the driver is zero or almost zero. Is adjusted so that the idling engine speed, that is, the idling speed is maintained in the vicinity of the desired target speed.

  During the idling operation, the ECU 0 increases the power generation amount of the generator 110, that is, the output voltage as the atmospheric pressure is lower, and decreases the output voltage of the generator 110 as the atmospheric pressure is higher. However, in the region where the atmospheric pressure is less than the predetermined value, the output voltage of the generator 110 is lowered as the atmospheric pressure is lower. This is because when the atmospheric pressure is very low, the amount of intake air charged into the cylinder 1 of the internal combustion engine is also significantly reduced, making it difficult for the internal combustion engine to output surplus engine torque.

  Moreover, ECU0 raises the output voltage of the generator 110, so that idle speed is high, and it reduces output voltage of the generator 110, so that idle speed is low.

  In the memory of the ECU 0, map data or a function formula that prescribes the relationship between the idle speed and atmospheric pressure and the output voltage of the generator 110 is stored. The ECU 0 searches the map using the current idle speed and atmospheric pressure as keys, or substitutes the current idle speed and atmospheric pressure into the function formula to know the magnitude of the output voltage to be set. And the generator 110 is controlled to the state which outputs the said output voltage.

  The adjustment of the output voltage of the generator 110 according to the level of the atmospheric pressure at idling is performed when the atmospheric pressure is lower than a certain value (under an environment of low atmospheric pressure) and the amount of intake air charged into the cylinder 1 is determined. It is carried out on condition that it is below the fixed amount. Further, at the time of idling, the opening degree of the throttle valve 32 (or the idle speed control valve) is corrected simultaneously according to the level of atmospheric pressure. That is, as the atmospheric pressure is lower, the opening of the throttle valve 32 during idling is increased.

  In the present embodiment, the generator 110, which is an auxiliary machine that generates electric power by receiving the transmission of rotational torque from the internal combustion engine, is controlled based on the current engine speed and atmospheric pressure during idle operation of the internal combustion engine. A control device 0 for adjusting the output of the generator was configured.

  According to this embodiment, in an environment of low atmospheric pressure typified by high altitudes, the output of the generator 110 that generates electric power by following the internal combustion engine is increased more than the flat ground, and exceeds the torque necessary for maintaining idle rotation. Excessive engine torque can be spent on power generation to suppress acceleration of the rotation of the internal combustion engine. Therefore, the problem that the idling speed increases even when the opening of the throttle valve 32 (or idling speed control valve) is reduced to the lower limit at high altitudes is solved, and idling speed with intermittent fuel cut is eliminated. Hunting of numbers can be avoided, and drivability is kept high.

  Further, since the electric power generated by the generator 110 can be collected by charging the battery 120 and used for driving the electrical system thereafter, surplus engine torque (and fuel consumption) is not wasted.

  In addition, the load of the auxiliary machine, that is, the output of the generator 110 is increased as the atmospheric pressure becomes lower in the region where the atmospheric pressure is equal to or higher than the predetermined value, while it is decreased as the atmospheric pressure becomes lower in the region where the atmospheric pressure is lower than the predetermined value. Therefore, even in a situation where the atmospheric pressure is very low and the internal combustion engine cannot output surplus engine torque, the idle speed can be brought close to the desired target speed.

  The present invention is not limited to the embodiment described in detail above. In particular, the auxiliary device whose load is adjusted according to the engine speed and the atmospheric pressure during the idling operation of the internal combustion engine is not limited to the generator 110. For example, a compressor that pressurizes or compresses fluid by receiving rotational torque from an internal combustion engine is used as an auxiliary device to be controlled, and the control unit ECU0 increases or decreases the output of the auxiliary device, that is, the load on the internal combustion engine. Also good.

  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)
DESCRIPTION OF SYMBOLS 1 ... Cylinder 11 ... Injector 3 ... Intake passage 32 ... Throttle valve 110 ... Auxiliary machine (generator)
112 ... Coil (field coil)
130 ... Regulator

Claims (2)

Controlling an auxiliary machine that operates by receiving rotational torque from an internal combustion engine,
A control device for adjusting a load on the internal combustion engine of the auxiliary machine based on the current engine speed and atmospheric pressure during idle operation of the internal combustion engine. In a region where the atmospheric pressure is equal to or higher than a predetermined value, the load of the auxiliary machine increases as the atmospheric pressure decreases,
2. The control device according to claim 1, wherein in a region where the atmospheric pressure is less than a predetermined value, the load on the auxiliary device is reduced as the atmospheric pressure is lowered.

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