JP2008014194A - Engine control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine control device capable of improving traction performance while restraining the vibration and the slip. <P>SOLUTION: In the engine control device 6, a fuel injection device 3 for supplying fuel and a variable valve gear 5 for driving a suction valve 4 and an exhaust valve in such a manner of capable of varying the opening and closing timing are provided on cylinders of a multi-cylinder engine 1 of a vehicle, and the variable valve gear 5 and the fuel injection device 3 are respectively controlled for each of the cylinders. When the engine 1 is in the prescribed operation state, same phase explosion control is performed for the variable valve gears 5 and the fuel injection devices 3 of at least two of the cylinders wherein the phase of a piston 22 is set same so that the opening and closing time of the suction valve 4 and the exhaust valve is synchronized, and the fuel injection timing is synchronized, and thus, the cylinders are operated in the same stroke. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an engine control device for an engine provided with a variable valve device (variable valve mechanism).

  Conventionally, for example, as proposed in Patent Document 1, it is known that the traction performance can be improved by making the explosion intervals of a multi-cylinder engine unequal and increasing the torque fluctuation. .

  In the crank structure disclosed in Patent Document 1, the arrangement angle of each crankpin with respect to the rotation center of the crankshaft is set so that the explosions of the respective cylinders are at unequal intervals.

JP 09-166126 A

  However, in the crank structure described above, the explosion interval is defined by the phase of the crank (crank pin arrangement angle), and if it is an unequal interval explosion, it must always be an unequal interval explosion, The problem of vibration becomes prominent in the low speed rotation region, and the instantaneous torque becomes excessive in the high load region, which may result in slip.

  Accordingly, an object of the present invention is to provide an engine control device that can solve the above-described problems and improve traction performance while suppressing vibration and slip.

  In order to achieve the above object, the present invention provides a fuel injection device for supplying fuel to each cylinder of a multi-cylinder engine of a vehicle, and a variable valve operating device for variably driving the opening / closing timings of intake valves and exhaust valves. In the engine control device that controls each of the variable valve operating device and the fuel injection device for each cylinder, when the engine is in a predetermined operating condition, at least the phase of the piston is set to the same phase. The variable valve devices and the fuel injection devices of the two cylinders are controlled in the same phase so that the opening / closing timings of the intake valve and the exhaust valve are synchronized and the fuel injection timings are synchronized, and the cylinders are subjected to the same stroke. It is to be operated with.

  Preferably, in order to determine the predetermined operating condition, the engine load detecting means for detecting the engine load is connected to obtain a detection signal, and the engine load detected by the engine load detecting means is predetermined. When the load is equal to or greater than the load, the in-phase explosion control is prohibited and normal equidistant explosion control is performed.

  Preferably, in order to determine the predetermined driving situation, the engine is connected to the engine rotation speed detection means for detecting the rotation speed of the engine so as to obtain a detection signal, and is detected by the engine rotation speed detection means. When the rotational speed is less than a predetermined rotational speed, the in-phase explosion control is prohibited and normal equidistant explosion control is performed.

  Preferably, the engine is connected to a slip detection means for detecting a slip of the driving wheel of the vehicle so as to acquire a detection signal, and when the slip is detected by the slip detection means, the engine is in the predetermined driving state. Even so, the above in-phase explosion control is prohibited and normal equidistant explosion control is performed.

  According to the present invention, an excellent effect that traction performance can be improved while suppressing vibration and slip is exhibited.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  The engine control device of the present embodiment is applied to, for example, a multi-cylinder engine (hereinafter referred to as an engine) that has four or more even-numbered cylinders and is mounted on a vehicle.

  First, the engine of this embodiment will be described with reference to FIG.

  As shown in FIG. 1, the engine 1 has a plurality of (six in the illustrated example) cylinders 11 to 16. Further, a supercharger (not shown) is attached to the engine 1.

  Each of the cylinders 11 to 16 includes a combustion chamber 2 defined by a cylinder 21 and a piston 22, a fuel injection device 3 for injecting and supplying fuel to the combustion chamber 2, and an intake port 41 communicating with the combustion chamber 2. An intake valve 4 for opening and closing the engine (two in each cylinder in the example), an exhaust valve (not shown) for opening and closing an exhaust port communicating with the combustion chamber 2, and the intake valve 4 and the exhaust valve The variable valve operating device 5 for variably driving the opening / closing timing of the engine and the engine control device 6 for controlling the variable valve operating device 5 and the fuel injection device 3 for each cylinder are provided.

  The piston 22 is accommodated in the cylinder 21 so as to be slidable in the vertical direction, and is connected to the crankpin 25 of the crankshaft 24 via the connecting rod 23.

  In the present embodiment, the arrangement angle of the crankpin 25 with respect to the center of the crankshaft is such that the first cylinder 11 (the leftmost cylinder in FIG. 1) and the sixth cylinder 16, the second cylinder 12 and the fifth cylinder 15, The third cylinder 13 and the fourth cylinder 14 are set at the same angle.

  That is, the piston 22 of the first cylinder 11 and the sixth cylinder 16, the piston 22 of the second cylinder 12 and the fifth cylinder 15, the piston 22 of the third cylinder 13 and the fourth cylinder 14 are the same. Set to phase.

  The supercharger includes a compressor provided in the intake passage and a turbine provided in the exhaust passage, and the turbine is rotated by the exhaust from the combustion chamber 2 and the turbine rotates the compressor via the turbine shaft. To do.

  The variable valve operating device 5 is a so-called camless type valve operating device and preferably has a high degree of freedom in opening and closing control of the intake valve 4 and the exhaust valve. For example, an application by the present inventors, International Publication No. WO2002 / 079614 The “valve drive device for an internal combustion engine” described in 1) can be considered.

  Although not shown, for example, the variable valve operating device 5 includes a pressure chamber to which a pressurized working fluid (for example, high-pressure fuel) for opening the intake valve 4 (exhaust valve) is supplied, and its pressure. Working fluid supply means for operating the intake valve 4 (exhaust valve) in the opening direction by supplying high-pressure working fluid to the chamber, and closing the intake valve 4 (exhaust valve) by discharging the working fluid from the pressure chamber It may be provided with a working fluid discharge means to be actuated, and any means can be used as long as the valve opening and closing timing can be variably controlled.

  The variable valve gear 5 is connected to the engine control device 6 to receive a control signal.

  The engine control device 6 transmits a control signal to the variable valve operating device 5 to control the opening / closing timings of the intake valve 4 and the exhaust valve, respectively.

  The engine control device 6 is connected to transmit a control signal to the fuel injection device 3, and controls the injection amount and injection timing of the fuel injection device 3 based on the operating state of the engine 1.

  The engine control device 6 is connected to various sensors such as an engine rotation speed detection means, an engine load detection means, and a slip detection means, and detection signals from these sensors are input.

  The engine rotation speed detection means of the present embodiment includes a crank angle sensor 26 attached to the crankshaft 24 of the engine 1, and the engine control device 6 calculates the engine rotation speed from the detection value of the crank angle sensor 26.

  The engine load detection means of the present embodiment includes an accelerator opening sensor 27 that detects the amount of depression of the accelerator pedal and a crank angle sensor 26, and the engine control device 6 uses the engine calculated from the detection value of the crank angle sensor 26. The fuel injection amount is calculated based on the rotation speed and the detected value of the accelerator opening sensor 27, and the fuel injection amount is used as the engine load.

  The slip detection means of the present embodiment includes, for example, an ABS wheel speed sensor 28 attached to the drive wheel side of the vehicle.

  As will be described in detail later, when the engine 1 is in a predetermined operating state, the engine control device 6 has two cylinders (for example, the second cylinder 12 and the fifth cylinder) in which the phase of the piston 22 is set to the same phase. 15), each variable valve operating device 5 and each fuel injection device 3 are controlled in the same phase in order to synchronize the opening and closing timings of the intake valve 4 and the exhaust valve and to synchronize the fuel injection timing. Operate in the same stroke.

  The engine control device 6 has a map (variable valve mechanism basic operation map) for determining whether or not to perform the in-phase explosion control according to the operating state of the engine 1 (in the illustrated example, the engine rotation speed and the fuel injection amount). , (See reference symbol M in FIG. 6).

  Next, the control contents of the engine control device 6 of the present embodiment will be described based on FIGS. 1 to 6.

  The engine control device 6 according to the present embodiment sequentially controls the equidistant explosion in which each cylinder 11 to 16 of the engine 1 explodes (combusts) the fuel at equal intervals and explodes (combusts) the fuel simultaneously in at least two cylinders. The in-phase explosion control is switched according to the engine operating condition, road surface condition, and the like.

  First, the equidistant explosion control will be described based on FIG. 1 and FIG.

  FIG. 1 shows a schematic diagram of the stroke of a normal (equally spaced explosion control) four-cycle six-cylinder engine 1.

  For example, in the case of the first cylinder 11 and the sixth cylinder 16 in which the physical phases of the pistons 22 are the same in the four-cycle six-cylinder engine 1 of the normal equidistant explosion control shown in FIG. 1, the first cylinder 11 is exhausted. When the stroke is at the top dead center, the sixth cylinder 16 is at the top dead center of the compression stroke. Similarly, the second cylinder 12 and the fifth cylinder 15, and the third cylinder 13 and the fourth cylinder 14 have the same piston phase and different valve timings of 360 ° CA (Crank Angle [deg.]). Therefore, in this case, the explosion interval is 120 ° CA at regular intervals.

  As an example, FIG. 2 shows the piston positions of the second cylinder 12 and the fifth cylinder 15 and the valve operations of the intake valve 4 and the exhaust valve during the equidistant explosion control.

  In FIG. 2, the horizontal axis indicates the crank angle, and the vertical axis indicates the piston position in the upper stage, the in-cylinder pressure and valve lift amount of the second cylinder in the middle stage, and the in-cylinder pressure and valve lift amount in the fifth cylinder in the lower stage. Indicates.

  As shown in the upper part of FIG. 2, the piston phases are equal, but as shown in the middle part and the lower part, the valve timing is naturally different by 360 ° CA, so that each stroke is also shifted by 360 ° CA.

  Next, the in-phase explosion control will be described with reference to FIG.

  Since the engine 1 of this embodiment has the variable valve operating device 5, the intake valve 4 or the exhaust valve can be operated at an arbitrary timing without being restricted by a physical mechanism such as a cam. Therefore, the operations of the intake valve 4 and the exhaust valve can be shifted by 360 ° CA.

  As an example, FIG. 3 shows the piston positions of the second cylinder 12 and the fifth cylinder 15 and the valve operations of the intake valve 4 and the exhaust valve during the in-phase explosion control.

  In FIG. 3, the horizontal axis indicates the crank angle, and the vertical axis indicates the piston position in the upper stage, the in-cylinder pressure and valve lift amount of the second cylinder in the middle stage, and the in-cylinder pressure and valve lift amount in the fifth cylinder in the lower stage. Indicates.

As shown in the lower part of FIG. 3, as a result of shifting the operation of the intake valve 4 and the exhaust valve of the fifth cylinder by 360 ° CA, the second cylinder 12 and the fifth cylinder 15 perform the same phase cycle. .
Similarly, the first cylinder 11 and the sixth cylinder 16, and the third cylinder 13 and the fourth cylinder 14 can also be in the same phase cycle. At this time, the apparent explosion interval is equal to 240 ° CA.

  Thus, the valve operations of the first cylinder 11 and the sixth cylinder 16, the second cylinder 12 and the fifth cylinder 15, the third cylinder 13 and the fourth cylinder 14 are in phase, and By making the fuel injection timings of the cylinders in the same phase the same, the two cylinders perform the same phase cycle.

  The result of the cycle simulation when this in-phase explosion is applied is shown in FIG.

  In FIG. 4, the horizontal axis indicates the crank angle, and the vertical axis indicates the torque of the engine 1.

  As shown in line D (in-phase explosion) in FIG. 4, the instantaneous torque increases compared to line T (equal-interval explosion) due to the two cylinders exploding at the same time. The characteristics can be improved. In addition, the negative torque period becomes longer, and it is possible to recover the grip.

  In other words, slips occur at each explosion in equidistant explosions (also called equal explosions), whereas in in-phase explosions (also called same explosions), the timing of each explosion is longer, so slipping during one explosion occurs. However, since the grip recovers quickly, the overall slip amount is less than that of the iso-explosion.

  Here, simply speaking, the slip of the grip force recovery due to the explosion can be said to be an instantaneous minute slip due to the explosion.

  In addition, the slip includes a slip in the front-rear direction and a slip in a right-angle direction (vehicle width direction).

  Thus, in the present embodiment, in the even-cylinder engine 1 having four or more cylinders, by using a variable valve operating apparatus having a high degree of freedom, two cylinders having the same phase of the piston 22 are set to the same phase cycle. The torque fluctuation can be increased and the traction performance can be improved.

  Next, the relationship between the equidistant explosion control and the in-phase explosion control and the turbine inlet pressure of the supercharger will be described with reference to FIG.

  In FIG. 5, the horizontal axis indicates the crank angle, and the vertical axis indicates the inlet pressure of the turbine.

  As shown in FIG. 5, during in-phase explosion control (see line D), two cylinders explode in the same phase (simultaneously), so that the dynamic pressure peak is at equal interval explosion control (see line T). As a result, an improvement in turbine efficiency can be expected as seen in Japanese Patent Application Laid-Open No. 2003-343300, which is an application by the present applicant.

  Thus, in the present embodiment, it is possible to increase the dynamic pressure in the exhaust, thereby improving the turbine efficiency.

  Next, based on FIG. 6, the control flow by the engine control apparatus 6 of this embodiment is demonstrated.

  The engine control device 6 of the present embodiment basically controls the variable valve operating device 5 and the fuel injection device 3 by map control.

  That is, in order to solve the problems of vibration and excessive torque in the low rotation region and high load region, the in-phase explosion application region is limited as shown in the variable valve mechanism basic operation map M in FIG.

  Specifically, as shown in FIG. 6, first, in step S <b> 3, the engine control device 6 calculates the detected value of the engine speed sensor (engine speed in FIG. 6) and the fuel injection amount calculated by itself. get.

  Next, in step S4, the engine control device 6 performs normal operation (equal interval explosion control) or phase change (in-phase explosion) based on the engine speed and fuel injection amount and the variable valve mechanism basic operation map M. Control).

  Note that the boundary line B between the in-phase explosion and the equidistant explosion in the variable valve mechanism basic operation map varies vertically depending on the road surface condition and the driving condition.

  As described above, the engine control device 6 performs the in-phase explosion control when the fuel injection amount (engine load) calculated from the detection values of the engine speed sensor and the crank angle sensor 26 is equal to or greater than the predetermined injection amount (load). Prohibit and perform regular equidistant explosion control.

  More specifically, as shown in FIG. 6, the engine control device 6 performs in-phase explosion control when the engine load is low (in the example shown, a predetermined lower limit injection amount L or less), and performs high load (see FIG. 6). In the example, when the predetermined upper limit injection amount U is exceeded), equidistant explosion control is performed, and in the case of a medium load (in the example illustrated, the lower limit injection amount L is exceeded and the upper limit injection amount U is less than or equal to), the engine speed is used. Select either the equidistant explosion control or the in-phase explosion control.

  That is, the engine control device 6 basically performs in-phase explosion control when the engine load is medium load, but when the engine rotation speed calculated from the detected value of the crank angle sensor 26 is less than a predetermined rotation speed, Prohibit in-phase explosion control and perform regular equidistant explosion control.

  Here, in the boundary (transition) region between the in-phase explosion control and the equidistant explosion control, there is a concern that slip due to excessive instantaneous torque may occur due to the influence of the road surface condition or the like.

  Therefore, in the present embodiment, slip determination using the existing ABS wheel speed sensor 28 is performed, and when slip of the drive wheel is detected, the in-phase explosion is canceled and normal operation is performed.

  Specifically, the engine control device 6 performs a slip calculation (for example, comparison of rotational speed between the driving wheel and the driven wheel) from the detection value of the ABS wheel speed sensor 28 in step S1, and the driving wheel slips in step S2. Judge whether or not.

  If it is determined in step S2 that the driving wheel is slipping, normal operation (equal-interval explosion control) is performed.

  As described above, the engine control device 6 is connected to the ABS wheel speed sensor 28 for detecting the slip of the driving wheel of the vehicle so as to obtain a detection signal, and when the slip is detected by the ABS wheel speed sensor 28. Even if the engine 1 is in a predetermined operating condition, the in-phase explosion control is prohibited and normal equidistant explosion control is performed.

  As described above, in the present embodiment, by performing the in-phase explosion control using the variable valve gear 5, the traction performance is improved while suppressing the vibration in the low rotation region and the slip in the high load region. Can do. That is, in the low-speed rotation region and the high-load region in the medium load region, the problem of vibration and the like does not occur by performing normal equidistant explosion.

  Further, since exhaust is simultaneously performed in two cylinders, the turbine inlet pressure is increased, and the turbine efficiency can be improved.

  At the time of extremely low load such as idling, the vibration tends to increase both in vibration and noise compared to normal operation (equal explosion), but there is no problem as long as it is practically unnoticeable.

  In addition, this invention is not limited to the above-mentioned embodiment, Various modifications and application examples can be considered.

  For example, in the present embodiment, the engine control device 6 is applied to the in-line 6-cylinder engine 1, but the present invention is not limited to this.

FIG. 1 is a schematic diagram of an engine control apparatus according to an embodiment of the present invention. FIG. 2 is a diagram for explaining the relationship among the piston position, the pressure in the cylinder, and the valve lift amount in the equidistant explosion. FIG. 3 is a diagram for explaining the relationship among the piston position, the cylinder pressure, and the valve lift amount in the same-phase explosion. FIG. 4 is a diagram for explaining torques in an equidistant explosion and an in-phase explosion. FIG. 5 is a diagram for explaining the turbine inlet pressure in the equidistant explosion and the in-phase explosion. FIG. 6 is a diagram for explaining a control flow performed by the engine control apparatus of the present embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 3 Fuel-injection apparatus 4 Intake valve 5 Variable valve apparatus 6 Engine control apparatus 11-16 Cylinder 22 Piston

Claims (4)

Each cylinder of a multi-cylinder engine of a vehicle is provided with a fuel injection device for supplying fuel and a variable valve operating device for variably driving the opening and closing timings of intake and exhaust valves, and these variable valve operating devices, In the engine control device that controls the fuel injection device for each cylinder,
When the engine is in a predetermined operating condition, the opening and closing timings of the intake valve and the exhaust valve are synchronized between the variable valve devices and the fuel injection devices of at least two cylinders whose piston phases are set to the same phase. In addition, an engine control device characterized in that in-phase explosion control is performed so that fuel injection timings are synchronized, and the cylinders are operated in the same stroke.   When the engine load detected by the engine load detecting means is greater than or equal to a predetermined load, the engine load detecting means is connected to the engine load detecting means for detecting the engine load to determine the predetermined operating condition. The engine control device according to claim 1, wherein phase explosion control is prohibited and normal equidistant explosion control is performed.   In order to determine the predetermined operating condition, the engine rotational speed detecting means for detecting the rotational speed of the engine is connected, and the engine rotational speed detected by the engine rotational speed detecting means is less than the predetermined rotational speed. The engine control device according to claim 1 or 2, wherein the same phase explosion control is prohibited and normal equidistant explosion control is performed. Connected to the slip detection means for detecting the slip of the driving wheel of the vehicle so as to obtain a detection signal, and when the slip is detected by the slip detection means, the engine is in the predetermined operating condition. 4. The engine control device according to claim 1, wherein the in-phase explosion control is prohibited and normal equidistant explosion control is performed.

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