JP2603348B2 - Method and apparatus for controlling engine torque - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for controlling the torque of a twisted engine.

It is known that conditions can occur that cause vehicle speed to cause vehicle vibration that causes vibration in the torque output from the engine. This torque oscillation may be audible and may also cause physical vibration of the car, commonly referred to as "kangarooing" in the UK. In some vehicles, engine torque oscillations are caused by engine resonance frequency, transmission and final drive mismatches, which are inherent in some vehicles and engine speeds. It has already been proposed to monitor the rate of change in engine speed and to vary the torque output of the engine by changing the ignition timing to reduce the effects of this torque oscillation. In other words, if a decrease in engine speed is detected by the monitor operation, engine torque is increased by advancing ignition to counteract the decrease. Similarly, the increase in engine speed is counteracted by delaying ignition,
Vibration is suppressed.

This device is only possible if the resonance conditions are known and under these conditions the amount of phase shift between engine speed and vehicle wheel speed is constant. Therefore, a necessary change in ignition timing is evaluated.

There is another condition that results in "kangarooing", which occurs during acceleration. Here, the phase shift between engine and wheel speed is not constant, so that the previously proposed technique cannot be used.

The present invention relates to a motor vehicle comprising the steps of obtaining a signal representative of engine speed, detecting a sensed rate of change in engine speed, and varying an ignition angle in a direction opposing a change in engine torque. A method for controlling the torque of an internal twisted engine of the invention further comprising obtaining a signal representative of the wheel speed of the vehicle, detecting a difference between the signal representative of the speed of the engine and the wheel, and responsive to the detected difference. A method is provided wherein the ignition angle is varied. BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of the invention, embodiments of the invention are described by way of example with reference to the accompanying drawings, in which: FIG.

FIG. 1 is a basic block diagram representing an automobile, represented as a spring mass system, and FIG. 2 is a block diagram similar to FIG. 1 but useful for explaining the effects of the present invention. And FIG. 3 is an oscillograph showing the effectiveness of the present invention with engine torque controlled to be in phase opposite to transmission torque.

Automobiles have an engine, transmission, vehicle mass and tires. All of these can be described as a spring / mass system with a natural frequency excited by the acceleration of the vehicle.

This spring / mass system can be represented in simplified form as two mass transmitters, one mass is the engine and the other is the vehicle. The vehicle mass can be converted into a mass moment of inertia for the rotating mechanical system and taken into account. By considering the transmission line as spring elasticity, the equation defining the spring / mass system representing the vehicle is: θm · φm = Mm−Mg Mg = Cg (φm−φg) θf · φg = Mg−Mf Mf = Cf− φg.

Here, φm is the angle of the shaft on the motor side φg is the angle of the shaft on the transmission side 1 / Cg is the elasticity of the shaft θm is the moment of inertia of the engine θf is the moment of inertia of the vehicle Mf is the reverse torque from the vehicle Mg is the torque on the transmission side The shaft torque Mm is the torque of the shaft on the engine side.

These equations are represented as a block diagram as shown in FIG. 1, where block 1 represents the moment of inertia of the engine, block 2 represents the elasticity of the transmission, and block 3 represents the moment of inertia of the vehicle. I have. If the engine torque Mm suddenly increases, the increased reverse torque Mf occurs on the transmission side of the shaft, resulting in vibration.

The present invention changes the engine torque by changing the ignition angle in such a way that the engine torque oscillates in antiphase and the resultant torque acting on the centrifugal mass of the engine is constant, controlling the vibration, It proposes to brake the "kangarooing" or backing during acceleration, which is synthesized (generated).

FIG. 2 is a diagram showing on the basis of FIG. 1 how this is performed. The diagram of FIG. 2 differs from the basic diagram of FIG. 1 in that a loop for handling signals representing the speed of the engine and the vehicle is added. As explained previously, the phase difference between engine and wheel speed is not constant during acceleration backing or "kangarooing". In FIG. 2, a signal ng representing the vehicle speed is fed back and compared with a signal nm representing the engine speed. When the difference between nm and ng is transmitted to the engine side, this difference is used to operate the transmission torque monitoring device 4 including the integrator. The output of the integrator of the monitoring device 4 provides an output signal S, which is converted into an ignition timing correction value through a load / speed dependent engine ignition map 5, whereby the engine torque is shown in FIG. Is controlled so that the phase is opposite to that of the vehicle vibration.

If possible, the integrator of the monitoring device should have a time constant Tb almost equal to the stiffness of the transmission shaft, Cg
It is desirable to have. In addition, the output signal S from the integrator is fed back as indicated by block FB to cause the engine torque to oscillate with respect to the time period as shown in FIG. Harmonized or operatively coupled.
Moreover, this feedback connection ensures that under steady state conditions, zero output is provided from the monitor even when the engine speed is not equal to the transmitted vehicle speed.

The integrator is a counter for digital devices,
Regarding the analog device, a capacitor may be used. However, whichever device is used, care must be taken to obtain an accurate time constant.

Continued on the front page (72) Inventor Schlein, Bernhard, Germany D-7141 Oberleiksingen Zwingerstraße 1 (72) Inventor Wild, Ernst Germany D-7141 Oberleiksingen Wernerstrasse 20/6 ( 56) References JP-A-58-48738 (JP, A) JP-A-62-276272 (JP, A) JP-A-59-113269 (JP, A)

Claims (6)

(57) [Claims] 1. A method for controlling the torque of an internal combustion engine of a vehicle, comprising the steps of: forming a signal representative of the speed of the engine; and varying the ignition angle in a direction that counteracts variations in engine torque. Forming another signal (ng) representing the wheel speed, determining a difference between the engine speed (nm) and the signal representing the wheel speed (ng), and varying the ignition angle in response to the determined difference. And how. 2. The method of claim 1 wherein said difference signal is integrated and said integrated signal is used as an input to a load / speed dependent engine ignition map. 3. The method according to claim 2, wherein said integration is performed by a feedback loop. 4. A device for obtaining a signal (nm) representing the speed of the engine, a device for obtaining another signal (ng) representing the wheel speed of the vehicle, and subtracting both signals to generate a composite signal. 2. An integrator (4) for integrating said combined signal, and an apparatus (5) for obtaining an ignition angle correction signal. An apparatus for performing the described method. 5. The apparatus according to claim 4, wherein said integrator (4) includes a feedback loop (FB). 6. Apparatus according to claim 4, wherein said integrator has a time constant that is a function of the elasticity of the transmission.