JPS63289245A - Torque control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To make it possible to reduce a fluctuation component of torque generated by an internal combustion engine without incurring a reduction in responsiveness of acceleration and deceleration by detecting the fluctuation component of the torque and controlling a load torque to be absorbed by an accessory so as to reduce the fluctuation component only. CONSTITUTION:An a.c. generator (accessory) 5 is driven through a V-belt 4 by the power of an internal combustion engine 1. A crank angle sensor as means for detecting a fluctuation in rotational acceleration of a crankshaft indicative of a fluctuation component of torque of the internal combustion engine 1 is included in a distributor 3. A pulse interval of an output from the crank angle sensor is measured by a microcomputer 6, and the fluctuation in rotational acceleration of the crankshaft per rotational angle is computed by the microcomputer 6. Further, a load torque (quantity of power generation) of the generator 5 required for reducing the fluctuation is calculated to be defined as a control command. Then, the quantity of power generation of the generator 5 is increased or decreased by a power generation quantity controller 7 according to the control command, thereby increasing or decreasing the load torque to be absorbed by the generator 5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an internal combustion engine, and particularly to a torque control device for an internal combustion engine suitable for reducing fluctuation components of torque generated during operation.

[Conventional technology]

Conventionally, in internal combustion engines, gas torque fluctuates due to changes in cylinder pressure caused by suction compression of the air-fuel mixture, expansion of combustion gas, etc., and rotational inertia changes due to changes in the angle of the connecting rod with respect to the crankshaft. It is well known that the When such torque fluctuation components are transmitted to various devices driven by the internal combustion engine, torsional vibrations occur in those devices.

This may cause performance deterioration or equipment damage. Furthermore, the reaction of this torque fluctuation component is transmitted from the cylinder block to the parts that support the internal combustion engine and the chassis, causing vibrations in the internal combustion engine and the entire vehicle.
It is necessary to sufficiently reduce the magnitude of the fluctuation component of the torque generated by the internal combustion engine.

To address these issues, conventional approaches have been to increase the inertial mass of the flywheel in order to reduce torsional vibration, and to increase the rigidity of the support member to avoid resonance with the support member in order to reduce internal combustion engine vibration. decrease. Furthermore, in order to directly reduce torque fluctuations, as seen in JP-A-58-185938 and JP-A-61-171612, a reverse torque is applied to the crankshaft in synchronization with the increase in torque generated by the internal combustion engine. A method has been proposed in which the torque fluctuation component is reduced by generating the torque.

[Problem that the invention seeks to solve]

However, in the above conventional technology, an increase in the inertial mass of the flywheel causes a deterioration in responsiveness to acceleration/deceleration of the rotational speed, and a decrease in the rigidity of the support member causes a reaction to the large rotational torque generated by the internal combustion engine during sudden acceleration. This may actually cause the internal combustion engine to vibrate significantly.
Furthermore, with the conventional method of generating reverse torque, it is impossible to follow changes in torque due to speed changes because it is an open-loop control (Japanese Patent Laid-Open No. 58-L85938), and the magnitude of the load torque cannot be adjusted to the rotational acceleration itself. Because it is made proportional, it not only reduces the fluctuation component of torque, but also suppresses the increase and decrease of the average component of torque during acceleration and deceleration, resulting in a decrease in responsiveness to acceleration and deceleration.
171612) and the need to provide new equipment.

Furthermore, in the prior art, it has been difficult to generate load torque in sufficient synchronization with the fluctuating component of torque generated by the internal combustion engine for reasons explained below. In other words, in order to detect a torque that fluctuates at high speed, calculate the magnitude of the load torque necessary to cancel the fluctuation component of this torque, and change the load torque by some control means, a series of detection, calculation, and control is required. This means that the processing speed must be increased as the rotational speed of the engine increases, which is difficult to handle with existing control technology.

FIG. 12 is a diagram showing gas torque generated by one cylinder of a four-cycle engine as an example of torque fluctuations generated by the internal combustion engine. 1 combustion cycle of a 4-stroke engine,
In other words, the four strokes of intake, compression, combustion, and exhaust correspond to 720" in terms of the rotation angle of the crankshaft. In particular, in the combustion stroke, there is a very large fluctuation in torque due to the combustion gas pressure. If the engine has multiple cylinders 1For example, if the engine has 4 cylinders, the 12th
The same torque fluctuations as shown in the figure are superimposed four times, resulting in 1
This is the fluctuation in gas torque within one combustion cycle of the engine. Adding to this the variation in inertia torque due to variation in rotational inertia results in the variation in torque actually generated by the engine (Figure 13).

In this way, the torque fluctuation component generated by the internal combustion engine changes rapidly and complexly depending on the rotation angle of the crankshaft even within one combustion cycle of the engine, so the auxiliary equipment absorbs it in real time by following the torque fluctuation. It is difficult to change the load torque. However, when looking at one combustion cycle of an engine, torque fluctuation is a periodic pulsation phenomenon that is repeated with one combustion cycle of the engine as one period, and when looking at the rotation angle of the same crankshaft within one combustion cycle, The value does not change much. Therefore, for example, if the load torque at each rotation angle in the next cycle is controlled using the torque fluctuation component detected at each rotation angle one combustion cycle before and the control amount calculated based on it, the load torque at each rotation angle in the next cycle can be controlled. You can increase the effect.

On the other hand, the difference between the torque generated by the engine and the load torque absorbed by auxiliary equipment appears as rotational acceleration of the crankshaft.
Among these, the average rotational acceleration represents the average component of the torque that is effectively used to accelerate or decelerate the rotational speed, and the rotational acceleration variation represents the fluctuation component of the torque that causes problems such as the aforementioned torsional vibration.

Therefore, if this rotational acceleration fluctuation of the crankshaft is detected and the load torque is controlled to reduce this, the fluctuation component of the generated torque will be reduced, and the auxiliary equipment installed integrally with the engine will be able to reduce the fluctuation component of the torque. By absorbing this, fluctuation components no longer appear in the torque reaction force acting on the engine body, and vibrations of the engine support members and the entire vehicle can be reduced. Further, since only the rotational acceleration fluctuation, that is, the torque fluctuation component is reduced, and the change in the useful average torque component is not hindered, responsiveness to acceleration and deceleration does not deteriorate with control.

The present invention has been made in view of the above ideas. In other words, in an internal combustion engine equipped with a main power transmission system and an auxiliary drive transmission system, the fluctuation component of the torque generated by the engine at each rotation angle of the crankshaft within one combustion cycle of the engine is expressed as Based on the most recently obtained rotational acceleration fluctuation, calculate the magnitude of the load torque absorbed by the auxiliary equipment necessary to make the rotational acceleration fluctuation 0 at each rotation angle. The magnitude of the load torque can be controlled based on the calculated control amount. For example, if the auxiliary machine is a generator, the load torque can be increased or decreased by increasing or decreasing the amount of power generated by the generator. can.

Furthermore, since the period of the fluctuation component of the torque generated by the internal combustion engine can be considered to be almost fixed at each rotation angle within one combustion cycle of one engine, the current control amount at each rotation angle is held and its value is If the load torque is controlled while correcting it using the most recently obtained rotational acceleration fluctuation,
It is possible to suppress the influence of disturbances such as noise that appears sporadically in the detection means, sudden abnormal combustion, etc., and only the dominant fluctuation component of the generated torque is reduced, enabling more reliable control. become.

Furthermore, if the internal combustion engine is a multi-cylinder engine, for example a 4-cycle 4-cylinder engine, if the generated torque of each cylinder is considered to be the same, then this generated torque will overlap with a phase shift at every rotation angle interval of 180°. It is also possible to perform control by regarding the angular interval as one cycle of the torque fluctuation component.

[Means for solving problems]

To achieve this object, the present invention provides an internal combustion engine that is provided with a main power transmission system and an auxiliary drive transmission system.

A detection means that detects the fluctuation component of the torque generated at each rotation angle of the crankshaft within one combustion cycle of the engine as a fluctuation in rotational acceleration of the crankshaft at each rotation angle, and an auxiliary machine installed integrally with the engine absorb control means for controlling the magnitude of the load torque to be absorbed by the auxiliary machine for each rotation angle; It is characterized by reducing the magnitude of the fluctuation component of the torque generated by the engine by controlling the magnitude while correcting it so that the one-rotation acceleration fluctuation becomes small.

[Effect]

According to the above-described configuration, the magnitude of the load torque absorbed by the auxiliary machine is controlled in accordance with the fluctuation component of the torque generated by the internal combustion engine, and the fluctuation component of the torque is eliminated or significantly reduced.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram schematically showing the configuration of a first embodiment of the present invention. In FIG. 1, an internal combustion engine 1 is
Engine body 2. From the distributor 32 engine with built-in crank angle sensor ■I'21 by belt 4! The engine main body 2 and an alternating current generator (ACG) 5, which is an example of an auxiliary machine, are mounted integrally with the engine main body 2. In addition, the output pulse interval of the crank angle sensor, which is a means for detecting rotational acceleration fluctuations of the crankshaft representing the fluctuation component of the torque of the internal combustion engine 1, is timed, and the rotational acceleration fluctuations for each rotation angle of the crankshaft are calculated, and this is reduced. ACG5 required to
After calculating the load torque (power generation amount) of A, the microcomputer 6 outputs a control command according to the rotation angle of the output, and the microcomputer 6 receives this command value and increases or decreases the power generation amount of the ACG 5.
A control system includes a power generation amount control section 7 that increases or decreases the load torque absorbed by the CG 5.

FIG. 2 is a diagram showing an example of output pulses from the crank angle sensor. As shown in the figure, when the rotational acceleration of the crankshaft changes, the time between output pulses also changes accordingly. The microcomputer 6 measures the output pulse interval using a timer 6a, and the CPU 6b calculates the rotational acceleration at each angle based on the value of the pulse interval at each rotation angle, and also calculates the rotational acceleration at each rotation angle based on the value of the pulse interval at each rotation angle. By taking a weighted moving average of the rotational acceleration ω at each rotation angle, the average rotational acceleration ω is obtained as shown in the following formula, where ω is; For example, ω is the rotational acceleration of the rotation angle of the crankshaft when the 2nd pulse is output, and ω is the average rotational acceleration at that position. Further, at represents a weight. Rotational acceleration The rotational acceleration fluctuation Δωk at each rotation angle can be obtained as −7−Δω=ω−ωk (2).

Note that the size of the weight al and the number n of pulses used for calculation
By taking into consideration the severity of changes in rotational acceleration, etc., and appropriately determining, a value close to the actual average rotational acceleration can be obtained. Figures 3 and 4.

Fig. 5 is a diagram showing the rotational speed of the crankshaft, 9 rotational acceleration, and 2 rotational acceleration fluctuation, respectively, when rotational acceleration fluctuation is added to a constant average rotational acceleration, together with the rotation angle on the horizontal axis. It is.

FIG. 6 specifically shows the configuration of the control circuit in order to explain the operation of the first embodiment in more detail. A.C.
G5 is a stator coil 5a that outputs AC power (three-phase output in FIG. 4), and a rotor coil 5 that supplies field current.
b, a rectifier 5c configured with a rectifier diode that converts the obtained alternating current into direct current, and an automatic voltage regulator (AVR) 5d that adjusts the output voltage to a constant value.

Now, when the magnetic field of the rotor coil 5b rotates due to the rotation of the rotor, the stator coil 5a generates electricity, which is then passed through the rectifier 5c to 1
Power is supplied to loads 8 such as ignition coils and lights, and to a battery 9. The torque fluctuation component of the internal combustion engine 1 appears as a rotational acceleration fluctuation of the crankshaft, and the crank angle sensor 1
Detected by 0. The detected rotation pulse is divided into frequency divider 1
After being divided into the minimum number of pulses required for control by 1,
The signal is input to the microcomputer 6, outputs a command signal using the method described above, and is sent to the power generation amount control section 7 via the D/A converter 12. The driver 16 of the power generation amount control section 7 is
The MOS switch 13 connected in parallel with the load 8 and the battery 9 is controlled in ○N/○FF. MOS switch 13
When it turns on, the circuit current bypasses it and flows through it, so a large current flows through the circuit.

That is, the load current can be increased or decreased by driving the driver 16 by P'WM control or the like and changing the duty ratio of 0N10FF of the MOS switch 13. When rotational acceleration fluctuations are large, increase the duty ratio and increase the load current.

The rotational acceleration fluctuations are suppressed by increasing the load torque and, conversely, when the rotational acceleration fluctuations are small, by decreasing the duty ratio and reducing the load current to reduce the load torque.

Next, FIG. 7 is a diagram showing details of the power generation amount control section. The low resistance 17 is provided in a part of the circuit, and this low resistance R
The load current amount i is obtained as a voltage drop of 5, and the amplifier 1
4 becomes the current detection value VIL, and the automatic current regulator (A
CR) sent to 15.

ACR15 is the current command value V of the microcomputer 6.
A feedback loop is constructed for the entire circuit so that is and current detection value Vtt are equal.

The chopper circuit 18 which forms a chopper signal using the output of the ACR 15 and the triangular wave oscillator 19 controls the duty of the MOS switch by pulse width modulation (PWM) so that the load current iL flowing through one circuit becomes equal to the current command value of the microcomputer. (See Figure 8).

FIG. 9 is a diagram illustrating the control flow of the control circuit described above. First, in step 110, when the number of pulses output by the crank angle sensor in one combustion cycle of the engine is N, when a pulse (kth) at a certain rotation angle of the crankshaft is detected, there is a gap between it and the k-1st pulse. The time interval tk is measured, and the rotational speed between the 11th and 2nd pano a is calculated by the reciprocal of the value of -2. Similarly, when the k+1st pulse is detected, the rotational speed ωhat is calculated from the time interval that with the kth pulse. From these ω birth and ω-11, the rotational acceleration ω corresponding to the th pulse is calculated by the following equation.

At the same time, the average rotational acceleration ω1゜(2
) Calculate the rotational acceleration fluctuation Δωk using the equation.

Next, in step 120, the load current command value isb in the k-th pulse is obtained by adding the current load current iLk multiplied by the rotational acceleration fluctuation Δω1 by the control gain kt.

1sh=i+,h+K・Δωh”・(4)
Calculate as follows. According to equation (4), when the rotational acceleration fluctuation Δω1 is positive, that is, the torque fluctuation component is positive, the load current ik is increased by K·Δω to increase the load torque absorbed by the ACG, and the torque Attempts to reduce positive fluctuation components. vice versa.

When the rotational acceleration fluctuation Δωk is negative, that is, when the torque fluctuation component is negative, the load current is reduced to reduce the load torque of the ACG, thereby trying to reduce the negative torque fluctuation component. Furthermore, when the rotational acceleration fluctuation is 0, the torque fluctuation component is 0, so the current load current value is directly used as the load current command value.

In step 130, the load current command value ish at the second pulse calculated in step 120 is stored.

Further, in step 140, each time a pulse is input, a load current command for each stored pulse is outputted to control the duty ratio of 0N10FF of the MOS switch.

Since rotational acceleration fluctuations of the crankshaft occur periodically at fixed angles with respect to the rotation angle, as mentioned above, the method of calculating the load current value command value is to use the latest obtained value as the current command value. If the rotational acceleration fluctuation is corrected by adding a value multiplied by the control gain, even if an accidental fluctuation component appears, the instability of controllability due to this can be minimized, and the torque fluctuation component can be corrected. Since the dominant components of can be reliably controlled, more reliable control can be performed.

Figure 10 shows the torque generated by the internal combustion engine and the load absorbed by the auxiliary equipment! - It is a diagram showing an example of the torque without any fluctuation component that is finally generated by the engine as a result of the control.

Next, FIG. 11 shows a second embodiment according to the present invention. In contrast to the load current control in the first embodiment shown in FIG. 6, this is intended to control the field current of the rotor coil to suppress fluctuations in the rotational acceleration of the crankshaft.

In other words, when the field current is increased, the terminal voltage increases and AC
The amount of torque required for driving G5 also increases. therefore,
The amount of load torque may be calculated by the microcomputer 6 from the rotational acceleration fluctuation of the engine one combustion cycle ago obtained by the crank angle sensor 10, and the amount of field current flowing through the rotor coil 5b may be controlled in synchronization with the command value output. . As a means for this, as shown in FIG.
30 and turn the emitter-grounded transistor switch 32 OFF via the driver 31. When the transistor switch 32 is in the ON state, the field current flows from the collector to the emitter side, so that current also flows in the rotor coil 5b, and conversely, when the transistor switch 32 is in the FF state, no current flows. Field current control can be performed by changing the duty ratio of ○N/○FF at this time.

Here, the diode 33 is a feedback diode for causing current due to overvoltage to flow back to the power supply side, and the diode 34 is a diode for preventing terminal voltage fluctuations due to field current control from being applied to the load side.

〔Effect of the invention〕

As described above, according to the present invention, the fluctuation component of the torque generated in the internal combustion engine is detected, and the load torque absorbed by the auxiliary equipment is controlled so as to reduce only the fluctuation component of the torque. without deteriorating responsiveness.
Not only can the fluctuation component of the torque transmitted to the main power transmission system be reduced, but also the vibration of the engine or vehicle due to torque reaction force can be reduced.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of an internal combustion engine and a torque control circuit according to a first embodiment of the present invention, and Figs. 2 to 5 show the output pulse of the crank angle sensor and the rotation speed, 1 rotation acceleration, and 9 rotation acceleration fluctuations. Figures 6 to 8 are circuit diagrams of the torque control device and chopper signals used therein, Figure 9 is a control flow diagram of the torque control device, and Figure 10 is a diagram showing the torque control device. Diagram showing an example of a torque waveform, No. 11
This figure shows a second embodiment of the present invention, and FIGS. 12 and 13 are diagrams showing examples of torque waveforms generated by an internal combustion engine. DESCRIPTION OF SYMBOLS 1... Internal combustion engine, 2... Engine body, 5... AC generator (ACG) which is an example of auxiliary equipment, 6... Microcomputer, 7... Power generation amount control unit, 10...・Crank angle sensor, 13... MOS switch, 32... Transistor No. 1 port 3... Monitor stribief 4°V 1trIfP No 7th δ Figure 9th Mouth 10th 1 person λ-yaki vehicle (4-cycle winnowing/opening service 72 field crank Akiyu 8 rotation angle

Claims (1)

[Claims] 1. In an internal combustion engine equipped with a main power transmission system and an auxiliary drive transmission system, one combustion cycle of the engine (converted to the rotation angle of the crankshaft is 720° in the case of a 4-stroke engine, 2 A detection means for detecting the fluctuation component of the torque generated at each rotation angle of the crankshaft within 360 degrees (in the case of a cycle engine) as a rotational acceleration fluctuation of the crankshaft at each rotation angle, and an auxiliary machine installed integrally with the engine. control means for controlling the magnitude of the load torque absorbed by the auxiliary machine for each rotation angle; 1. A torque control device for an internal combustion engine, characterized in that the magnitude of a fluctuation component of torque generated by the engine is reduced by controlling the magnitude of the torque while modifying the magnitude so that rotational acceleration fluctuation is reduced. 2. The control means sets the magnitude of the load torque absorbed by the auxiliary machine at each rotation angle of the crankshaft within one combustion cycle of the engine to the current magnitude, and the rotational acceleration at each rotation angle most recently obtained. 2. The torque control device for an internal combustion engine according to claim 1, wherein the torque control device for an internal combustion engine performs control while being corrected so as to have a magnitude equal to the value obtained by multiplying the fluctuation by a control gain. 3. A patent characterized in that, in the control means, the rotational acceleration fluctuation at each rotational angle of the engine one combustion cycle before is used as the latest rotational acceleration fluctuation at each rotational angle of the crankshaft within one combustion cycle of the engine. A torque control device for an internal combustion engine according to claim 1. 4. If the internal combustion engine is a multi-cylinder engine and each cylinder has the same shape of torque fluctuation component within each combustion cycle and is arranged at a constant angular interval, each cylinder The difference in angle between the two (converted to the rotation angle of the crankshaft: 720° for a 4-stroke engine, or 360° for a 2-stroke engine, divided by the number of cylinders) is calculated as the torque fluctuation component. Torque control for an internal combustion engine according to claim 1, characterized in that the magnitude of the load torque absorbed by the auxiliary equipment is controlled at each rotation angle of the crankshaft within one cycle, which is regarded as one fluctuation cycle. Device. 5. A generator is provided as the auxiliary machine, and by increasing the power generation amount of the generator, the load torque absorbed by the generator is increased, and conversely, by decreasing the power generation amount, the load torque is decreased. A torque control device for an internal combustion engine according to claim 1.