JP2014101849A - Control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress free-running feeling or rushing-out feeling of a vehicle while preventing accidental fire in light load running.SOLUTION: In a case when idle rotation control is executed during running of a vehicle by controlling idle rotation to converge an engine rotation speed to a target idle rotation speed in a combustion operation in which a treading amount of an accelerator pedal is 0 or a threshold value near 0 or less, a target idle rotation speed is raised by a prescribed amount, and a power generation amount by a power generator is increased. Thus combustion can be stabilized by increasing an intake amount and a fuel injection amount, and further increase of the engine rotation speed and a vehicle speed can be suppressed by distributing the increased engine torque to power generation in the power generator.

Description

  The present invention relates to an internal combustion engine mounted on a vehicle and a control device that controls a generator attached to the internal combustion engine.

  Perform feedback control to converge the engine speed to the minimum target idle speed when the engine torque does not need to be supplied to the axle (drive wheel) via the drive system, typically when the vehicle is stopped Is well known (see, for example, the following patent document).

  Such idle rotation control is also performed during light load traveling, such as when the vehicle is traveling on a downhill road, and the driver is stepping on little or no accelerator pedal. In a running operation under conditions where the intake air amount and fuel injection amount filled in the cylinder are small, combustion of the air-fuel mixture in the cylinder may become unstable and misfire may occur. Therefore, during light load driving, the target idle speed is increased more than that when the vehicle is stopped, and the opening of the ISC (Idle Speed Control) valve or electronic throttle valve is increased to increase the intake amount and the fuel injection amount. This prevents the occurrence of misfire.

  In recent years, constant efforts have been made to reduce the friction loss of internal combustion engines and drive systems with the aim of further improving fuel efficiency. As a result, when the target idle speed is increased during light load driving, the engine speed and vehicle speed may exceed the driver's assumptions, giving the driver a “feeling of running” or a “feeling of jumping out”. Led to a decline.

Japanese Unexamined Patent Publication No. 2000-170800

  An object of the present invention is to suppress the feeling of idling or popping out of a vehicle while preventing misfire during light load traveling.

  In the present invention, an internal combustion engine mounted on a vehicle and a generator that generates electric power by receiving a driving force from the internal combustion engine are controlled, and an accelerator pedal depression amount is 0 or less than a threshold value close to 0. When performing idle speed control that converges the engine speed to the target idle speed during a certain combustion operation and performing the idle speed control while the vehicle is running, the target idle speed is raised and the amount of power generated by the generator is increased. The control apparatus characterized by making it comprise was comprised.

  That is, by raising the target idle speed, the intake air amount and the fuel injection amount charged in the cylinder are increased to stabilize the combustion and prevent misfire. At the same time, the increased engine torque is directed to the power generation in the generator, so that energy is recovered in the form of electric power while suppressing an increase in engine speed and vehicle speed.

  ADVANTAGE OF THE INVENTION According to this invention, the idling feeling of a vehicle or a jumping-out feeling can be suppressed, preventing misfire at the time of light load driving | running | working.

The figure which shows the whole structure of the internal combustion engine for vehicles in one Embodiment of this invention. The circuit diagram of the electrical system in the same embodiment. The timing diagram explaining the content of the idle rotation control which the control apparatus of the embodiment implements.

  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 four-stroke 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, a throttle valve 32, a surge tank 33, and an intake manifold 34 are arranged in this order from the upstream. In addition, an ISC valve 36 for adjusting the opening degree of the flow path 35 is provided in the bypass flow path 35 that short-circuits the upstream side and the downstream side of the throttle valve 32 in the intake passage 3.

  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.

  In automobiles, electric power is generated using a part of the output of the internal combustion engine, and the generated electric power is charged in the on-vehicle battery 120, and is installed in an ECU (Electronic Control Unit) 2 that is a control device for controlling operation and the vehicle body. It is usual to supply various electric loads 5 such as a fan motor, a heater, a defogger, an audio device, a car navigation system, etc. for air-cooling a condenser of an illuminating lamp, a radiator or an air conditioner.

  FIG. 2 shows a circuit diagram of the electrical system. Each of the electric loads 5 is connected in parallel to the battery 120 and the alternator 110 that are power sources. The electrical load 5 is energized via an energization circuit provided with a relay device 6 or a power device (power semiconductor element) 7 typified by a power transistor, power MOSFET or the like. Then, the energization to the electric load 5 is turned ON / OFF by the switching operation of the relay switch 6 or the power device 7. It is also possible to input the ignition signal q that causes the switch operation of the power device 7 to the power device 7 and to PWM control the voltage applied to the electric load 5.

  The alternator 110, which is a generator, rotates upon receiving a driving force transmitted from the crankshaft of the internal combustion engine. The magnitude of the voltage generated and output by the alternator 110 is controlled via the regulator 130. The regulator 130 is a known IC type attached to the alternator 110. The output voltage of the alternator 110, that is, the voltage induced in the stator coil, increases in proportion to the DUTY ratio of the field current flowing through the field coil, that is, fDUTY. The regulator 130 receives a signal l for instructing the output voltage of the alternator 110 from the ECU 2 and performs PWM control for adjusting fDUTY so as to realize the instructed output voltage.

  The ECU 2 that controls the operation of the internal combustion engine and the control of the auxiliary machine 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 (N signal) b output from an engine rotation sensor that detects the rotation angle of the crankshaft and the engine speed, 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 (in other words, a required load), the intake air temperature in the intake passage 3 (particularly, the surge tank 33). And an intake air temperature / intake pressure signal d output from a temperature / pressure sensor for detecting intake pressure, a coolant temperature signal e output from a water temperature sensor for detecting engine coolant temperature, and a gradient of a road surface on which the vehicle is currently located. And an acceleration signal f output from an acceleration sensor that detects the acceleration of the vehicle, and a sensor that detects the amount of depression of the brake pedal. Brake pedal amount signal g, cam angle signal (G signal) h output from the cam angle sensor at a plurality of cam angles of the intake camshaft or exhaust camshaft, battery current and battery temperature related to the charge / discharge status of the battery 120 Battery signal n output from the sensor to be detected, and an operation input device (operation switch) operated by a user's hand who desires to operate an illumination light, an air conditioner, a heater, a defogger, an audio device, a car navigation system, etc. , A button, a touch panel, etc.) 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 ISC valve 36, an output voltage command signal l for the regulator 130, An ON signal p is output to the relay switch 6 on the energization circuit of the electrical system, and an ignition signal q is output to the power device 7.

  The processor of the ECU 2 interprets and executes a program stored in advance in the memory, calculates operation parameters, and controls the operation of the internal combustion engine. The ECU 2 obtains various information a, b, c, d, e, f, g, h, n, o necessary for operation control of the internal combustion engine via the input interface, and knows the engine speed and also uses the cylinder 1 Estimate the amount of intake air to be filled. In addition, the state of charge of the battery 120 and the operating status of various electric loads 5 are known, and the power to be generated by the alternator 110 is estimated. Then, operating parameters such as required fuel injection amount, fuel injection timing (including the number of times of fuel injection for one combustion), fuel injection pressure, ignition timing, power generation voltage of the alternator 110, and the like are determined. As the operation parameter determination method itself, a known method can be adopted. The ECU 2 applies various control signals i, j, k, l, p, and q corresponding to the operation parameters and the user's operation via the output interface.

  The ECU 2 of the present embodiment is configured so that the measured engine speed and the target idle speed are equalized in order to converge the engine speed to the target idle speed in a situation where it is not necessary to supply engine torque to the axle via the drive system. Feedback control is performed to adjust the opening of the ISC valve 36 (that is, the intake air amount) and the fuel injection amount of the injector 11 according to the deviation. This idle rotation control is performed not only when the vehicle is stopped, but also when the driver is driving lightly, such as when the driver is stepping on little or no accelerator pedal.

  In a situation where the vehicle is traveling on a flat road or a downhill road and the vehicle speed is higher than a certain level, a drive system (for example, a torque converter, a forward / reverse switching device (clutch), and a drive system interposed between the crankshaft and the axle of the internal combustion engine) Although the automatic transmission is not disconnected, its drive train and axle are hardly a mechanical load on the internal combustion engine. During such light load traveling, the throttle valve 32 has a very small opening and the intake air amount and the fuel injection amount charged into the cylinder 1 are small, so that the combustion of the air-fuel mixture in the cylinder 1 tends to become unstable. is there.

  Therefore, in order to prevent misfire, the ECU 2 of the present embodiment sets the target idle speed from that when the vehicle is stopped in idle rotation control during light load traveling where the amount of depression of the accelerator pedal is 0 or less than a threshold value close to 0. Is also set to a high value by a predetermined amount. The raising amount of the target idle speed is larger than the raising amount in the idle rotation control of the conventional system.

  As a result, as shown in FIG. 3, the amount of intake air flowing through the bypass passage 35 in idle rotation control during light load traveling (or the opening of the ISC valve 36; indicated by a solid line) is the idle rotation when the vehicle is stopped. The amount of intake air flowing through the bypass passage 35 in the control (represented by a broken line) becomes larger, and the intake air amount and fuel injection amount charged into the cylinder 1 increase.

  Further, as shown in FIG. 3, the ECU 2 increases the power generated by the alternator 110 while raising the target idle speed, in other words, the output voltage of the alternator 110, and the output voltage before raising the target idle speed. Higher than. Thereby, since the mechanical load of the alternator 110 with respect to the internal combustion engine increases, acceleration of the crankshaft and the axle accompanying the increase of the intake air amount and the combustion injection amount is suppressed. Since the electric power generated by the alternator 110 is stored in the battery 120 and used for the subsequent operation of the electric load 5, it leads to energy saving.

  According to the present embodiment, the internal combustion engine mounted on the vehicle and the generator 110 that generates electric power by receiving the supply of driving force from the internal combustion engine are controlled, and the depression amount of the accelerator pedal is set to 0 or 0. When performing the idle rotation control for converging the engine speed to the target idle speed during the combustion operation that is less than or equal to the near threshold value and performing the idle speed control while the vehicle is traveling, the target idle speed is raised and the generator 110 is increased. Since the control device 2 is configured to increase the amount of power generated by the vehicle, it is possible to suppress the feeling of running or jumping out of the vehicle while preventing misfire during light load traveling.

  The present invention is not limited to the embodiment described in detail above. For example, when the bypass passage 35 and the ISC valve 36 are not present in the intake passage 3 of the internal combustion engine and an electronic throttle valve that allows the ECU 2 to freely operate the opening degree is mounted, the ISC valve is controlled in idle rotation control. Instead of 36, the opening of the electronic throttle valve is adjusted.

  The generator 110 may be a motor generator that also has a function of rotationally driving a crankshaft or an axle of an internal combustion engine. In this case, the electric power generated when the target idle speed is raised and stored in the battery 120 can be reused as a driving force for rotating the crankshaft or the axle.

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

  The present invention can be used to control an internal combustion engine and a generator mounted on a vehicle.

2. Control device (ECU)
110 ... Generator (alternator)
120 ... Battery

Claims (1)

An internal combustion engine mounted on a vehicle and a generator for generating electric power by receiving a driving force from the internal combustion engine;
Idle rotation control for converging the engine speed to the target idle speed during combustion operation in which the accelerator pedal depression amount is 0 or less than a threshold value close to 0,
A control device characterized in that when the idle rotation control is carried out while the vehicle is running, the target idle rotation speed is increased and the amount of power generated by the generator is increased.

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