JPH04238239A - Rotating speed control device for engine - Google Patents

Abstract

PURPOSE:To detect and control the engine rotating speed of a vehicle with high precision while using rollers with a relatively small diameter in a chassis dynamometer performing the test of the vehicle with a tire of the completed vehicle mounted on the rollers directly connected to the dynamometer. CONSTITUTION:A means detecting the rotating speed of a tire 5L, a means detecting the rotating speed of a roller, and a control device, which obtains the engine rotating speed from the tire rotating speed by conversion, obtains the slip quantity from detection signals of the tire rotating speed and the roller rotating speed and their radiuses, obtains the effective radius of the tire 5L changed by the vehicle speed from the calculation of the slip quantity, and controls the engine rotating speed, are provided.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chassis dynamometer for measuring engine output characteristics of a completed vehicle, and more particularly to an engine speed control device.

0002

2. Description of the Related Art A chassis dynamometer conducts various performance tests including the power transmission system from the engine to the wheels of a vehicle, and is constructed as shown in FIG. Power is changed from the engine 1 via the clutch and transmission 2 and transmitted to the output shaft 3, and is further transmitted to the differential gear (differential gear) 4.
To test a vehicle that obtains driving force from the left and right rear (or front) tires 5L, 5R through It is mounted on a single twin roller, to which a dynamometer (electric motor) 7 as a pseudo load and a flywheel (not shown) that provides inertia of the vehicle are coupled. The absorption (or drive) torque and speed of the dynamometer 7 are controlled by its control device 8, and the control device 8 controls the amount of operation of actuators 9 and 10 mounted on the vehicle, and controls the actuator 9 to operate the accelerator lever 11 of the vehicle. The opening degree control and intake negative pressure control of the throttle lever 12 of the engine 1 are performed by operation, and the gear ratio switching control is performed by the operation of the vehicle's transmission lever 13 by the actuator 10. Furthermore, in manual transmission vehicles, it also controls actuators connected to the clutch pedal and brake pedal. The control of these dynamometers and actuators enables durability tests and driving performance tests of completed vehicles. For these controls, a torque meter 14 is installed on the twin rollers 6Lm, 6Ls, 6Rm, and 6Rs as a measurement system.
and a speed detector 15, and actuators 9 and 1 are provided.
0 is provided with a stroke detector (not shown), and further provided with an exhaust gas measuring device and the like.

[0003] Here, to measure the net output characteristics of the engine 1, which is one of the test items of the chassis dynamometer,
The rotation speed of the engine 1 is controlled. Since the engine 1 is mounted on the finished vehicle for this rotation speed control, the speed cannot be directly detected from the engine 1. Therefore, roller 6
The speed of the engine 1 is detected by converting from the rotational speed detection of Lm, 6Ls, 6Rm, 6Rs or the dynamometer output shaft, that is, the detected speed from the speed detector 15. This conversion is performed according to the following formula.

[0004] Ne=Nd(Rr/Rt)×It×Id...
(1) However, Ne: Engine rotation speed Nd: Roller rotation speed Rr: Roller diameter Rt: Tire diameter It: Gear ratio Id: Differential gear ratio

[0005]

[Problems to be Solved by the Invention] Conventional speed detection calculations for engine rotation speed control are performed on rollers 6Lm, 6Ls,
Slip due to contact between 6Rm, 6Rs and tires 5L, 5R (
If there is no slippage, the engine speed can be detected with high accuracy. In the case of a single roller with a large roller diameter such as 1061φ or 1592φ, the contact area between the tire and the roller becomes larger, reducing the slip rate.
Speed can be detected with relatively high accuracy. However, with small-diameter (502φ) rollers that are used in small-scale equipment such as twin rollers, the contact area between the rollers and tires is small, resulting in a high slip rate, making it difficult to detect high-precision speeds and, in turn, control the engine speed. It disappears.

An object of the present invention is to provide a control device that detects and controls the engine rotation speed of a completed vehicle with high accuracy while using a roller with a relatively small diameter.

[0007]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention places the tires of a test vehicle on a roller, and controls the engine rotational speed of the test vehicle by controlling the absorption or driving force of a dynamometer directly connected to the roller. In a chassis dynamometer that performs control, a tire rotation speed detection means detects the rotation speed of the tire, a roller rotation speed detection means detects the rotation speed of the roller, and a rotation speed of the engine is determined from a detection signal of the tire rotation speed. The radius of the tire determined from the change characteristics of the tire effective radius with respect to changes in vehicle speed, the running distance of the tire determined from the tire rotation speed, and the travel distance of the roller determined from the radius of the roller and the rotation speed of the roller. The present invention is characterized by comprising a control device that determines the slip of the rollers and tires and controls the engine rotation speed.

[0008]

[Operation] According to the present invention configured as described above, by determining the engine rotation speed from the detection signal of the tire rotation speed, the engine rotation speed is detected without the presence of slip between the engine and the detection signal, The engine rotation speed is controlled by determining the amount of slip between the tire and the roller from both the roller rotation speed and tire rotation speed detection signals, and the slip detection is determined as the ratio of the tire travel distance to the roller travel distance. By including the change in the effective radius with respect to the change in vehicle speed in the calculation, accurate slip detection and, in turn, accurate engine speed control can be obtained.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram of an apparatus showing an embodiment of the present invention, and parts equivalent to those in FIG. 3 are designated by the same reference numerals. Tire 5L
A reflective sticker 21 having a black and white striped pattern in the radial direction is pasted on its side surface. A photodetector 22 is provided at a position facing the reflective sticker 21, and detects the light projected onto the reflective sticker 21 and the level of the reflected light, and distinguishes between the reflected light from the white part of the striped pattern and the reflected light from the black part. A light-to-electrical conversion is performed in which the difference in level is associated with the pulse signal level. By means of the reflective seal 21 and the photodetector 22, a pulse signal having a frequency proportional to the rotational speed of the tire 5L can be obtained as an output of the photodetector 22. Note that the reflective sticker 21 is attached to the tire 5.
Instead of attaching it to L, it may be attached to the wheel part of the wheel or a disc may be attached.

The counter 23 inputs the detection pulse signal of the photodetector 22 and obtains the frequency of the detection pulse signal as a count value. For example, it may be configured to count clock pulses for one period of detection pulses or to count the number of detected pulses within a certain period of time. With this configuration, the count value of the counter 23 obtains a value proportional to the rotation speed of the tire 5L, that is, a tire rotation speed detection signal.

The speed detector 15 is connected to the roller 6L as in the conventional case.
The rotation speed of m or 6Ls or the rotation speed of the dynamometer 7 is detected. The configuration of this detector is a simple configuration in which the reflective sticker 21 is pasted on the tire part of a completed vehicle to be tested, while a semi-permanent configuration, for example, a disc 15A with a slit around the periphery is attached to a roller or the like. An optical detector 15B, which is fixed concentrically and detects light transmission from this slit, is used, and furthermore, a magnetic detector is made using a metal disk having irregularities around the periphery and a magnetic circuit.

The control device 24 has a microcomputer as its control center, and periodically takes in the detection signals of the counter 23 and the speed detector 15 as input data, respectively, and controls the engine rotation speed based on both detection signals. In addition, in order to control the absorption or driving force of the dynamometer 7, the control device 24 also provides a control voltage command or frequency (
speed) and voltage command. Furthermore, the control device 24 provides necessary control signals to the actuators 9, 10, etc.

Engine speed control will be explained in detail below. A rotation speed detection device comprising a reflective sticker 21, a photodetector 22, and a counter 23 detects the rotation speed of the tires of the completed vehicle. This rotational speed is proportional to the engine rotational speed without intervening slip between it and the engine 1, and the engine rotational speed can be accurately determined from the following conversion formula.

Ne=Nt×It×Id...(
2) However, Ne: Engine rotation speed Nt: Tire rotation speed It: Gear ratio Id: Differential gear ratio Therefore, from the above equation (2), engine rotation speed detection in engine rotation speed control cannot be accurately determined from tire rotation speed. can. Here, the engine rotation speed control is performed by controlling the rotation speed of the roller 6Lm that is directly connected to the dynamometer 7. Therefore, in addition to the tire rotation speed, the roller rotation speed is input from the speed detector 15 to the control device 24. , detecting slippage between rollers and tires improves the accuracy of engine speed control. That is, in order to control the engine speed, it is necessary to give a speed command including slip to the dynamometer 7 directly connected to the roller. This slip S is determined by the following equation from the ratio of the travel distances of the roller rotation speed and the tire rotation speed, using the respective speed detection signals as variables.

S=(Nt×2π×Rt)/(Nd×2π×Rr)
...(3) However, Nt: Tire rotation speed Rt: Tire radius Nd: Roller rotation speed Rr: Roller radius π: Pi control device 24 calculates the slip S by calculation according to the above equation (3), This slip S is substituted into the following equation to obtain the dynamo speed command, and the desired speed control of the engine is obtained.

N=(Nd×Rr/Rt)×It×Id×S
...(4) Here, the effective radius Rt of the tires 5L and 5R changes by several millimeters depending on the vehicle speed, and the above (
3) An error occurs in the detected slip value in equation 3 due to vehicle speed. Therefore, in this embodiment, the actual tire radius Rt is
The tire radius Rt is used to calculate the slip amount according to the above equation (3), and further, the engine rotation speed is controlled according to the equation (4). Figure 2 shows a vehicle speed-tire radius characteristic diagram, where the tire effective radius Rt when running is determined by the function Rt=f(RT,V), which decreases as the vehicle speed V increases, compared to the tire radius RT when stopped. Measurement is also possible.

Therefore, in this embodiment, when controlling the engine rotation speed of a completed vehicle, the engine rotation speed can be detected with high accuracy by detecting the tire rotation speed using a sticker attached to the tire and a photodetector. . Then, to control the engine rotation speed, the roller or dynamo rotation speed is detected, and slip between the tire and the roller is detected from this detection signal and the tire rotation speed detection signal.In addition, when detecting slip, the change in the tire effective radius due to the vehicle speed is detected. Calculations including this are performed, and by controlling the dynamo rotation speed including this slip, accurate engine rotation speed control can be performed even in the case of small diameter rollers. Further, in combination with the control of the actuator 9 of the throttle lever, it is possible to control the intake pressure of the engine in controlling the engine rotation speed.

Although the embodiment shows a case where a reflective sticker and a photodetector are used to detect the rotational speed of a tire, the present invention is not limited to this, and a disc is attached to a wheel to detect an optical Alternatively, equivalent effects can be obtained by appropriately changing the design, such as one that detects magnetically.

[0019]

As described above, according to the present invention, the engine rotation speed is determined by detecting the tire rotation speed, and the slip amount is determined from both the roller rotation speed and tire rotation speed detection signals.
In order to find this amount of slip, calculations that include changes in the tire's effective radius due to vehicle speed are performed to control the engine rotation speed, making it possible to detect engine rotation speed with high precision without the intervention of slip. In addition, it is possible to accurately control the engine rotation speed by detecting the amount of slip that eliminates the error caused by changes in the effective radius of the tire.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a vehicle speed-tire radius characteristic diagram.

FIG. 3 is a conventional configuration diagram.

[Explanation of symbols]

1...Engine 2...Transmission 5L, 5R...tire 6L, 6R...Roller 7...Dynamometer 9,10...actuator 21...Reflective sticker 22...Photodetector 23...Counter 24...control device 25...Power converter 26...Selector switch

Claims (2)

[Claims] [Claim 1] Place the tires of a test vehicle on rollers,
A chassis dynamometer that controls the engine rotation speed of a test vehicle by absorption or driving force control of a dynamometer directly connected to the roller, comprising a tire rotation speed detection means for detecting the rotation speed of the tire, and a tire rotation speed detection means for detecting the rotation speed of the roller. a roller rotation speed detection means for detecting the rotation speed of the engine, and a tire radius determined from the tire radius determined from the change characteristic of the tire effective radius with respect to a change in vehicle speed and the tire rotation speed determined by converting the rotation speed of the engine from the detection signal of the tire rotation speed. and a control device that controls the engine rotation speed by determining the slip between the roller and the tire from the travel distance of the roller determined from the travel distance of the roller, the radius of the roller, and the rotation speed of the roller. Device. [Claim 2]