JP2015121142A - Controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the precision of a determination on a combustion state of an air-fuel mixture in a cylinder of an internal combustion engine.SOLUTION: Relative displacement of an internal combustion engine mounted on a vehicle from a vehicle body when an air-fuel mixture is burnt normally is estimated from an operation region of the internal combustion engine, actual relative displacement of the internal combustion engine from the vehicle body is known through a displacement sensor, and the displacement estimated from the operation region of the internal combustion engine is compared with the displacement known through the displacement sensor so as to determine whether the air-fuel mixture is burnt normally.

Description

  The present invention relates to a control device for a vehicle equipped with an internal combustion engine.

  As a method of detecting that the combustion of the air-fuel mixture has become unstable or misfired in the cylinder of the internal combustion engine, a method of referring to the rotational fluctuation of the internal combustion engine (see, for example, Patent Document 1 below) or an ion current signal is referred to. A method (for example, see Patent Document 2 below) is known.

  The former calculates the amount of decrease in the rotational speed by repeatedly measuring the time required for the crankshaft, which is the output shaft of the internal combustion engine, to rotate by a predetermined angle, and if the amount of decrease exceeds the determination threshold, It is determined that an unstable or misfire has occurred.

  The latter detects the ionic current flowing through the electrode of the spark plug when the air-fuel mixture burns in the combustion chamber of the cylinder and measures its transition, and the length of the period when the magnitude of the ionic current is higher than a predetermined amount It is determined that combustion instability or misfire has occurred.

JP 2012-077700 A JP 2006-200432 A

  When judging the combustion state of the air-fuel mixture with reference to the rotational fluctuation of the internal combustion engine, depending on the operating region, there may not be a clear difference in the engine speed between normal combustion and bad combustion (misfire), Even if a misfire occurred, this could not be detected, or conversely, the possibility of misjudging that it was misfired despite normal combustion could not be denied.

  Even when the combustion state of the air-fuel mixture is determined with reference to the ion current signal, the detection level of the ion current varies depending on the properties of the fuel used, and the combustion state may not be determined correctly.

  An object of the present invention is to improve the accuracy of determination of the combustion state of an air-fuel mixture in a cylinder of an internal combustion engine.

  In the present invention, the relative displacement of the internal combustion engine with respect to the vehicle body when it is assumed that the air-fuel mixture burns normally is estimated from the operation region of the internal combustion engine mounted on the vehicle, and the actual vehicle body of the internal combustion engine Whether or not the air-fuel mixture is combusting normally by comparing the displacement estimated from the operating range of the internal combustion engine with the displacement obtained from the displacement sensor. A control device for determining whether or not was configured.

  ADVANTAGE OF THE INVENTION According to this invention, the precision of determination of the combustion state of the air-fuel | gaseous mixture in the cylinder of an internal combustion engine can be improved further.

The figure which shows the structure of the internal combustion engine and control apparatus in one Embodiment of this invention. The front view which shows the support structure of the internal combustion engine using the engine mount apparatus in one Embodiment of this invention. The sectional side view of the engine mount device. The sectional side view which shows the modification of an engine mount apparatus. The side view which shows the pattern of the displacement of the internal combustion engine with respect to a vehicle body. The figure which illustrates the output signal of the magnetic field detection element during operation of an internal-combustion engine. The figure which illustrates the output signal of the magnetic field detection element during operation of an internal-combustion engine.

  An embodiment of the present invention will be described with reference to the drawings. In FIG. 1, the outline | summary of the internal combustion engine M1 for vehicles in this embodiment is shown. The internal combustion engine M1 is a spark ignition type four-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 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.

  An external EGR (Exhaust Gas Recirculation) device 2 is attached to the internal combustion engine M1. The external EGR device 2 realizes a so-called high-pressure loop EGR. The EGR device 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 in the EGR passage 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.

  FIG. 2 shows an example of a support structure for mounting an internal combustion engine M1 and drive systems M2 and M3 mounted on a vehicle to a vehicle body M4 via an engine mount device M5.

  The support structure shown in FIG. 2 is of a so-called horizontal FF (Front-engine Front-drive) type. That is, the internal combustion engine M1 is disposed in front of the vehicle so that the crankshaft extends sideways so as to extend along the left-right direction of the vehicle. On the side of the internal combustion engine M1, a torque converter M2, a transmission case M3, and the like constituting the drive system are assembled, and these are integrated with the internal combustion engine M1. The left and right sides of the unit (one side of the internal combustion engine M1 and the other side of the transmission case M3) are attached to the subframe M41, which is a part of the vehicle body M4, via the engine mount device M5. A rear portion (torque converter M2) of the unit is connected to a front suspension member M42 which is a part of the vehicle body M4 via a torque rod M6. Both side portions of the unit are placed on the engine mount device M5 via the engine mount bracket M7.

  As shown in FIG. 3, the engine mount device M5 includes an attachment fitting M51 on the internal combustion engine M1 side that is fastened to the engine mount bracket M7, an attachment fitting M52 on the vehicle body M4 side that is fastened to the subframe M41, and these attachment fittings. The main components are a vibration isolating member M53 that is interposed between M51 and M52 and joins them, and a buffer liquid M54 sealed in a small chamber formed in the vibration isolating member M53.

  The anti-vibration member M53 is mainly composed of elastically deformable rubber or the like. The anti-vibration member M53 and the enclosed buffer liquid M54 prevent the vibration transmitted from the internal combustion engine M1 to the vehicle body M4, and the oscillation of the internal combustion engine M1 due to torque reaction force, input from the road surface, and the like. Operates the damping action to suppress.

  In addition, in the present embodiment, relative displacement of the internal combustion engine M1 with respect to the vehicle body M4 is placed inside an engine mount device M5 that mounts one side portion (side portion of the internal combustion engine M1) of the unit on the vehicle body M4. Implements a mechanism to detect

  Specifically, as shown in FIG. 3, the engine mount device M5 is fixed to the mounting magnet M51 on the internal combustion engine M1 side and fixed to the mounting body M52 on the vehicle body M4 side. A magnetic field detection element M56 is provided. The magnetic field detection element M56 is typically a Hall element that detects a magnetic field using the Hall effect, but other aspects such as a coil, a fluxgate magnetic field sensor, a Wiegand wire, and the like are used as the magnetic field detection element M56. It does not preclude adoption.

  When the internal combustion engine M1 is displaced relative to the vehicle body M4, the magnet M55 is displaced relative to the magnetic field detection element M56. According to the magnetic field detection element M56, the displacement amount and the direction of the displacement of the magnet M55 can be detected. As a result, it is possible to know the amount of displacement and the direction of displacement of the internal combustion engine M1 relative to the vehicle body M4. The magnetic field detection element M56 is connected to an ECU (Electronic Control Unit) 0 that controls operation of the internal combustion engine M1 and / or the drive systems M2 and M3.

  It should be noted that the displacement detection mechanism of the engine mount device M5 can be applied to an active engine mount. FIG. 4 shows a modified engine mount apparatus M5 that implements an active engine mount function. The engine mount device M5 according to the present modification includes a plurality of orifices M57 and M58 through which the enclosed buffer fluid flows, and valves M59 and M50 that can open and close the orifices M57 and M58. The other points are the same as those of the engine mount device M5 shown in FIG. That is, a permanent magnet M55 fixed to the mounting bracket M51 on the internal combustion engine M1 side and a magnetic field detection element M56 fixed to the mounting bracket M52 on the vehicle body M4 side are provided in the engine mount device M5. .

  The orifices M57 and M58 are arranged apart from each other in a direction orthogonal to the direction in which the crankshaft of the internal combustion engine M1 extends. When the internal combustion engine M1 is mounted on a vehicle by the horizontally placed FF method, the orifices are separated from each other in the front-rear direction.

  The valves M59 and M50 corresponding to the orifices M57 and M58 are, for example, solenoid valves that can be operated by inputting a control signal from the ECU 0. Through the operation of the valves M59 and M50, the orifices M57 and M58 can be opened and closed, or the openings of the orifices M57 and M58 can be expanded or reduced.

  FIG. 5 shows an example of relative displacement of the internal combustion engine M1 with respect to the vehicle body M4. As shown in FIG. 5A, the internal combustion engine M1 can swing back and forth with respect to the vehicle body M4. When the vehicle is accelerating or when the vehicle is traveling uphill, as shown in FIG. 5B, the internal combustion engine M1 is displaced relatively rearward so as to tilt backward with respect to the vehicle body M4. When the vehicle is decelerating or the vehicle is traveling downhill, as shown in FIG. 5C, the internal combustion engine M1 is displaced relatively forward so as to tilt forward with respect to the vehicle body M4. .

  When the air-fuel mixture is combusted in the combustion chamber of the cylinder 1, positive engine torque, that is, torque that accelerates rotation of the crankshaft acts on the crankshaft of the internal combustion engine M1. At this time, a force in the direction opposite to the rotation direction of the crankshaft acts on the main body of the internal combustion engine M1. That is, the main body of the internal combustion engine M1 is displaced rearward relative to the vehicle body M4. The amount of displacement increases as the positive engine torque acting on the crankshaft increases.

When the internal combustion engine M1 is displaced rearward relative to the vehicle body M4, the rear portion of the vibration isolating member M53 is deformed so as to be crushed, and the rear portion of the small chamber in which the buffer liquid M54 is sealed is compressed to have its volume. Shrinks. Thereby, the buffer liquid M54 flows downward in the orifice M58 at the rear. Further, the ECU 0 that has detected the rearward displacement of the internal combustion engine M1 with respect to the vehicle body M4, which may flow upward in the orifice M57 at the front, via the displacement detection mechanism, is at least a valve M50 attached to the orifice M58 at the rear. To close the orifice M58 or reduce its opening. Then, further deformation of the vibration isolating member M53 is prevented, and further rearward displacement of the internal combustion engine M1 is suppressed. At this time, the valve M59 attached to the orifice M57 at the front may be operated to close the orifice M57 or reduce the opening.

  In contrast, when the internal combustion engine M1 is displaced forward relative to the vehicle body M4, the front part of the vibration isolating member M53 is deformed so as to be crushed, and the front part of the small chamber in which the buffer liquid M54 is sealed is formed. Compressed to reduce its volume. Thereby, the buffer liquid M54 flows downward in the orifice M57 in the front. In addition, it may flow upward in the orifice M58 located at the rear.

  The ECU 0 that has detected the forward displacement of the internal combustion engine M1 with respect to the vehicle body M4 via the displacement detection mechanism operates at least the valve M59 attached to the orifice M57 at the front to close or open the orifice M57. Squeeze the degree. Then, further deformation of the vibration isolating member M53 is prevented, and further forward displacement of the internal combustion engine M1 is suppressed. At this time, the valve M50 attached to the rear orifice M58 may be operated to close the orifice M58 or reduce the opening.

  In the modification shown in FIG. 4, the valves M59 and M50 are attached to the front orifice M57 and the rear orifice M58, respectively, but the valves M59 and M50 are attached to only one of the orifices M57 and M58. May be.

  In the engine mount apparatus M5 shown in FIGS. 3 and 4, the magnet M55 is provided on the internal combustion engine M1 side and the magnetic field detection element M56 is provided on the vehicle body M4 side. The magnet M55 may be provided on the vehicle body M4 side, and the magnetic field detection element M56 may be provided on the internal combustion engine M1 side. In this case, the magnet M55 is fixed to the mounting member on the vehicle body M4 side, and the magnetic field detection element M56 is fixed to the mounting member on the internal combustion engine M1 side.

  The ECU 0 as the control device of the present embodiment 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 coolant temperature signal e output from the water temperature sensor that detects the coolant temperature of the engine M1, and the large pressure output from the atmospheric pressure sensor that detects the atmospheric pressure. An atmospheric pressure signal f, an inclination angle detected from an inclination angle sensor (or an acceleration sensor) that detects the inclination of the road surface on which the vehicle is located (or an acceleration sensor) Or an acceleration) signal g, a cam angle signal h output from the cam angle sensor at a plurality of cam angles of the intake camshaft or exhaust camshaft, and a displacement signal output from the magnetic field detection element M56 constituting the displacement detection mechanism. m and the like are input.

  From the output interface, the ignition signal i for the igniter of the spark plug 12, the fuel injection signal j for the injector 11, the opening operation signal k for the throttle valve 32, and the opening operation signal l for the EGR valve 23. An opening operation signal p is output to the valve M59, and an opening operation signal q is output to the valve M50.

  The processor of the ECU 0 interprets and executes a program stored in advance in the memory, calculates an operation parameter, and controls the operation of the internal combustion engine M1. The ECU 0 obtains various information a, b, c, d, e, f, g, h, m necessary for operation control of the internal combustion engine M1 through the input interface, knows the engine speed, and stores it in the cylinder 1. Estimate the amount of intake air to be filled. 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, required EGR rate (or EGR amount), and the like are determined. The ECU 0 applies various control signals i, j, k, l, p, q corresponding to the operation parameters via the output interface.

  The ECU 0 of the present embodiment refers to the relative displacement of the internal combustion engine M1 with respect to the vehicle body M4 detected via the displacement detection mechanism of the engine mount device M5, and the air-fuel mixture normally burns in the combustion chamber of the cylinder 1. It is determined whether or not

  FIG. 6 shows a magnetic field in a situation where the internal combustion engine M1 is in operation and the vehicle is stopped or is traveling steadily (the engine speed and the vehicle speed are not particularly accelerated or decelerated and can be regarded as a constant speed). The example of the displacement signal m which the detection element M56 outputs is shown. Needless to say, during operation of the internal combustion engine M1, the crankshaft of the internal combustion engine M1 is rotating, and the internal combustion engine M1 swings with respect to the vehicle body M4 due to the rotational speed and pulsation of the engine torque. Accordingly, as shown in FIG. 6, the displacement signal m output from the magnetic field detection element M56 vibrates.

  FIG. 6A shows the displacement signal m when the air-fuel mixture is burning normally in the cylinder 1. In this case, the internal combustion engine M1 in steady operation swings with a substantially constant amplitude and cycle with respect to the vehicle body M4, and the displacement signal m also vibrates with a substantially constant amplitude and cycle.

  On the other hand, FIG. 6B shows a displacement signal m when the combustion failure or misfire of the air-fuel mixture occurs in the cylinder 1. In this case, since the engine torque that should be output is lost at the moment when the combustion failure or misfire occurs, a waveform deviating from the vibration in the case of normal combustion appears in the displacement signal m. That is, the amplitude and / or cycle of the displacement signal m when a combustion failure or misfire occurs changes from the amplitude and / or cycle of the displacement signal m when normally burning.

  Incidentally, while the vehicle is stopped on the slope or traveling on the slope, the internal combustion engine M1 is tilted so as to be biased to one side with respect to the vehicle body M4. Biased to the side. 7A shows the displacement signal m when the vehicle is located on the uphill road, and FIG. 7B shows the displacement signal m when the vehicle is located on the downhill road. ing.

  The ECU 0 that determines the combustion state of the air-fuel mixture repeatedly samples the displacement signal m output from the magnetic field detection element M56 and acquires the time series. Then, the time-series maximum value, minimum value, average value, and / or vibration period (frequency) of the displacement signal m are obtained. Note that, as shown in FIG. 7, the time series local maximum value, local minimum value, and average value of the displacement signal m have a correlation with the gradient of the road surface on which the vehicle is currently located. Therefore, the ECU 0 corrects the time-series maximum value, minimum value, or average value of the displacement signal m in accordance with the gradient of the road surface detected through the inclination angle sensor (or acceleration sensor), and the maximum value, minimum value. Remove the effect of road slope from the value or average value.

  In addition, the ECU 0 is based on the current operation parameters including the operation region of the internal combustion engine M1 [the engine speed, the intake pressure in the surge tank 33 (or the required load, the intake amount charged into the cylinder 1, the fuel injection amount)]. The relative displacement of the internal combustion engine M1 with respect to the vehicle body M4 when the air-fuel mixture is normally burned is estimated. In the memory of the ECU 0, the engine speed, the intake pressure in the surge tank 33 (or the required load, the intake air amount charged into the cylinder 1, the fuel injection amount), the ignition timing, the vehicle speed, and the internal combustion engine M1 and the axle (drive) And the relative displacement of the internal combustion engine M1 (maximum value, minimum value, average value of its oscillation) when it is assumed that the air-fuel mixture is normally burned. , And / or the vibration period, etc.) is stored. The ECU 0 uses the current engine speed, the intake pressure in the surge tank 33 (or the required load, the intake amount charged into the cylinder 1, the fuel injection amount), the ignition timing, the vehicle speed, the transmission gear ratio, etc. as keys. The map is searched, and the estimated relative displacement when assuming that the air-fuel mixture burns normally (maximum value, minimum value, average value, and / or period of vibration of the internal combustion engine M1, etc.) )

  The ECU 0 actually measured the relative displacement amount of the internal combustion engine M1 estimated from the current operation parameters of the internal combustion engine M1 (obtained from the map data) via the displacement detection mechanism of the engine mount device 5 (and Compared with the relative displacement amount of the internal combustion engine M1, ie, the time series maximum value, minimum value, average value, and / or period of vibration of the displacement signal m (excluding the influence of the road surface gradient). If the difference between the former and the latter exceeds a predetermined amount, the ECU 0 determines that any combustion failure or misfiring of the air-fuel mixture has occurred in any of the cylinders 1.

  The ECU 0 that has determined that the combustion failure or misfire of the air-fuel mixture has occurred in any of the cylinders 1 executes a process for stabilizing the combustion of the air-fuel mixture in the cylinder 1. For example, the amount of fresh air filled in the cylinder 1 is increased, the EGR gas amount is decreased, the fuel injection amount is increased, or the ignition timing is advanced.

  In addition, when the combustion failure or misfire of the air-fuel mixture is repeated a predetermined number of times, the ECU 0 outputs a notification in the manner of appealing to the driver's visual sense that some abnormality is recognized in the internal combustion engine M1, and notifies the driver. For example, a warning light (engine check lamp) installed in the cockpit is turned on, a warning is displayed on the display screen, a buzzer, an alarm sound, and other sounds are output.

  In the present embodiment, the relative displacement of the internal combustion engine M1 with respect to the vehicle body M4 is estimated from the operating region of the internal combustion engine M1 mounted on the vehicle when it is assumed that the air-fuel mixture is normally burned. The relative displacement of the internal combustion engine M1 with respect to the vehicle body M4 is obtained through the displacement sensors M55 and M56, and the displacement estimated from the operating region of the internal combustion engine M1 and the displacement obtained through the displacement sensors M55 and M56 are obtained. Through the comparison, a control device 0 for determining whether or not the air-fuel mixture is normally combusted is configured.

  According to this embodiment, it is possible to improve the accuracy of determination of the combustion state of the air-fuel mixture in the cylinder 1 of the internal combustion engine M1. In particular, the method of the present embodiment that refers to the displacement signal m is used in combination with the method that refers to the rotational fluctuation of the internal combustion engine and the method that refers to the ionic current signal, thereby preventing combustion failure or misfire of the air-fuel mixture in the cylinder 1. It will be able to be detected reliably. Even though the air-fuel mixture burns normally, it is not erroneously determined to be bad combustion.

  Further, the variation in the combustion state for each cylinder 1 can be evaluated with reference to the displacement signal m.

  The displacement sensors M55 and M56 (displacement detection mechanism in the engine mount device M5) are capable of directly detecting the relative displacement of the internal combustion engine M1 with respect to the vehicle body M4, in other words, the behavior of the internal combustion engine M1. It can be manufactured at low cost.

  The displacement sensors M55 and M56 are used for purposes other than the determination of the combustion state of the air-fuel mixture, for example, measurement of engine torque (variation) output from the active engine mount system, internal combustion engine M1, and measurement of the center of gravity (variation) of the vehicle. It can be used for road surface gradient measurement.

  The present invention is not limited to the embodiment described in detail above. The specific configuration of each part can be variously modified without departing from the spirit of the present invention.

  The present invention can be applied to a control device for an internal combustion engine mounted on a vehicle.

0 ... Control unit (ECU)
M1 ... Internal combustion engine M4 ... Car body M5 ... Engine mount device M55, M56 ... Displacement sensor (magnet, magnetic field detection element)

Claims (1)

From the operating range of the internal combustion engine mounted on the vehicle, the relative displacement of the internal combustion engine with respect to the vehicle body when it is assumed that the air-fuel mixture burns normally is estimated,
Knowing the relative displacement of the actual internal combustion engine relative to the vehicle body via the displacement sensor,
A control device that determines whether or not the air-fuel mixture is normally combusted by comparing the displacement estimated from the operating region of the internal combustion engine with the displacement obtained through the displacement sensor.

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