JPH0216465B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a running resistance measuring device.

In order to test the durability of a vehicle, the vehicle is driven on a stand (chassis dynamometer) equipped with rotating rollers.
For this driving, the vehicle is actually driven on the road,
From this process, vehicle speed, throttle opening, and air pressure are measured as functions of time, and these are given as commands from a command generator to the vehicle on the stand, so that it operates under the same conditions as in actual driving. By the way, during operation on this bench, running resistance is one of the commands, and it is required to apply this as a load on the bench. However, running resistance is different from vehicle speed and cannot be obtained by actually driving the vehicle.
Therefore, in the past, this running resistance was regarded as a function of vehicle speed, and this was given from a command generator. It is clear that the running resistance obtained in this way does not exactly match that during actual running. However, in recent years, driving that is close to actual driving has become required by providing the vehicle on the stand with running resistance that fluctuates due to the effects of climbing boards, sharp curves, wind, etc. during actual driving. .

The purpose of this invention is to more accurately measure varying running resistance as a function of time.

The measurement of running resistance according to the present invention is carried out as follows. In other words, the vehicle used in the actual run is placed on the bench as is, and the throttle of the vehicle is operated to control the air pressure using the air pressure B(t) recorded during the actual run as a target value, thereby controlling the engine torque. Try to reproduce. On the other hand, the vehicle speed on the platform is
In order to match the vehicle speed V(t) recorded during actual driving,
Controls the load on the vehicle by passing dynamo current. Since the torque value of the dynamometer at this time can be regarded as a value expressing the running resistance in torque, this is converted into running resistance and stored together with the vehicle speed as a function of time in association with the vehicle. This memorized value is the running resistance R during actual driving.
(t).

The running resistance measured as described above is used as follows when reproducing the actual running conditions on the bench. That is, a test vehicle is placed on the bench in the same way, and its engine performs vehicle speed control using the stored vehicle speed V(t) as the target value as described above, and the dynamometer side controls the vehicle speed using the stored running resistance R(t) as the target value. ) is used as the target value to perform running resistance control. In this way, the test vehicle can be operated for durability under conditions extremely close to actual driving conditions.

Embodiments of the invention will be described with reference to the drawings. 1st
In the figure, 1 is a command generator, from which the vehicle speed, throttle opening, and air pressure measured and recorded when the vehicle was actually driven on the road are used as command vehicle speed V(t).
It is generated as a command throttle opening θ(t) and a command air pressure B(t). An example of the pattern of each of the above commands is shown in the second example.
As shown in the figure. In the figure, T ₁ represents the time period during starting and acceleration, and T ₂ represents the time period during steady driving.

In FIG. 2, a sudden depression in the throttle opening θ(t) and a sudden protrusion in the air pressure B(t) indicate that the gear is being shifted. In the following description, it is assumed that the shift position is controlled to the same shift position as in actual driving.

Since the intake pressure often decreases (becomes a negative value) with respect to atmospheric pressure (zero), it is expressed with the polarity reversed (negative values are read as positive values).
When you press the accelerator pedal, the throttle opening increases (throttle valve opens) and a mixture of fuel and air is sucked in, resulting in a pressure close to atmospheric pressure (a small value).

The commanded vehicle speed pattern is determined from the speedometer when the vehicle is actually running, and the commanded throttle opening pattern is determined by linking the displacement caused by pressing the accelerator pedal to the potentiometer.
and the command intake pressure pattern are obtained by measuring the pressure value of the air-fuel mixture near the intake manifold, and are stored as functions of the same time. This stored value may be output from the command generator 1.

2 is the deviation between the commanded intake pressure B(t), which is the target value, and the intake pressure of the vehicle when the vehicle (vehicle used for actual driving; hereinafter referred to as the target vehicle) is being driven on the bench. The deviation value from this is amplified by the control amplifier 3. 4 is an adder,
The output ε(t) of the control amplifier 3 and the commanded throttle opening θ(t) are added. 5 is a deviation device that calculates the deviation between the output ε(t)+θ(x) from the adder 4 and the signal corresponding to the throttle opening of the target vehicle (specifically, the signal corresponding to the amount of depression of the accelerator pedal). To detect. This deviation is amplified by a control amplification device 6 and sent to an operating device 7 that operates the accelerator pedal of the target vehicle.

The amount of operation by the operating device 7 is detected as a throttle opening position by a position detector 8, and is given to a deviation device 5 as a signal corresponding to the throttle opening. The deviation device 5, the control amplifier 6, the operating device 7, and the position detector 8 are a minor loop of the intake pressure control system. The intake pressure of the target vehicle is detected by an intake pressure detector 9, and is given to the deviation device 2 as a control value.

The commanded vehicle speed V(t) is given as a target value to the deflector 10, and the deviation from the vehicle speed (control value) of the target vehicle is calculated. This deviation is amplified by a control amplifier 11 and then by a current amplifier 12. This amplified output is supplied to the coil of the dynamometer 18 and applied as a load to the target vehicle. The vehicle speed of the target vehicle is detected by a vehicle speed detector 13 and given to the deviation device 10 as a control value.

Reference numeral 14 denotes a target vehicle, which is placed on rollers 15 that are rotatably supported. A flywheel 17 having an inertia equivalent to that of the target vehicle 14 and the above-mentioned dynamometer 18 which act as a load on the roller 15 are attached to the rotating shaft 16 of the roller 15. The aforementioned operating device 7 is installed to operate the accelerator pedal of the target vehicle 14. As a result, when the accelerator pedal is depressed, the intake pressure changes. This intake pressure is detected by an intake pressure detector 9. Further, the rotational speed of the rotating shaft 16 is detected as the vehicle speed of the target vehicle 14 by the vehicle speed detector 13. Current amplifier 1
2 is supplied to the coil of the dynamometer 18, and the larger the supplied current, the greater the rotational load on the roller 15. Also, when a current flows in the opposite direction, driving torque is generated.

A torque detector 19 detects the torque T(t) of the dynamometer 18 when the dynamometer 18 is controlling the vehicle speed. This detected value is converted into running resistance R(t) by the arithmetic amplifier 20,
The commanded vehicle speed V(t) is stored in the storage device 21 as a function of time. Running resistance is roller 15
Since it is a force that acts as a load on the vehicle in terms of R(t) is required.

In the above configuration, each command is issued from the command generator 1 while the engine of the target vehicle 14 is being driven. If there is a difference between the target vehicle's intake pressure detected by the intake pressure detector 9 and the command intake pressure B(t), a deviation ε(t) is output from the control amplifier 3, which causes the command throttle opening. The degree θ(t) is added by an adder 4, and a deviation from a signal corresponding to the throttle opening of the target vehicle at that time is outputted from a deviation device 5. As a result, the amount of operation by the operating device 7 is increased or decreased, and the intake pressure is controlled so as to always match the intake pressure command pattern. This is considered to be a reproduction of the engine torque during actual driving. On the other hand, the dynamometer also commands the vehicle speed of the target vehicle as vehicle speed V(t).
control to match the actual vehicle speed during actual driving. The value obtained by dividing the torque of the dynamometer at this time by the radius of the roller 15 is regarded as the running resistance, and this means that the running resistance can be measured.

As mentioned above, there are three pieces of data: vehicle speed;
Measure throttle opening and intake pressure during actual driving,
The recorded and actually driven vehicle is placed on the bench as it is,
Operate using the recorded data as command values.

That is, the intake pressure is controlled by manipulating the throttle opening, and the vehicle speed is controlled by increasing or decreasing the torque of the dynamometer. The value obtained by converting the torque at this time into running resistance is shown in the graph of running resistance R(t) at the bottom of FIG. 2.

By the way, in the above configuration, when controlling the intake pressure, if the commanded throttle opening θ(t) is not added to the adder 4, when the intake pressure changes quickly, the control delay will cause the commanded throttle opening degree θ(t) to reach the target value. This will be different from the command intake pressure B(t). Furthermore, if there is large nonlinearity in the relationship between throttle opening and intake pressure, there is a risk of instability. In order to solve this problem, the present invention adds the commanded throttle opening θ(t) to the manipulated variable.

The intake pressure is determined by the throttle opening and engine speed, so in order to reproduce the same intake pressure during bench driving as when actually driving, place the vehicle used in the actual driving on the bench as is, and adjust the throttle opening. This can be achieved by reproducing the same value as the degree and engine speed. The engine rotational speed only needs to be the same value as the gear shift position and vehicle speed during actual driving.

Commanded throttle opening θ(t) and commanded vehicle speed V(t)
Since this is data measured and recorded during actual driving,
Assuming that the throttle opening is controlled as θ(t) and the vehicle speed is V(t), if the shift position is controlled to be the same as when actually driving, the intake pressure will also be the same as when actually driving. It should match the intake pressure B(t).

In this case, it may be possible to provide only the commanded throttle opening θ(t) without configuring the intake pressure control system as shown in the figure. However, in reality, the intake pressures often do not match even if only the commanded throttle opening θ(t) is given due to mechanical deviation of the throttle opening detector. The discrepancy mentioned here is based on a change due to some cause between actual driving and bench operation.

For this reason, it is necessary to configure an intake pressure control system, and most of the necessary throttle opening degree both steadily and transiently can be obtained by the commanded throttle opening degree θ(t). Commanded throttle opening θ(t)
Adding this can be said to be a type of feed forward control. In this way, even if the deviation ε(t) in feedback control is small, that is, even if the loop gain is small, better control results can be obtained and the control system will be stabilized. The original intake pressure control system works to reduce steady deviations that change slowly.

As described in detail above, according to the present invention, the dynamometer side controls the vehicle speed and the engine side of the vehicle controls the intake pressure based on the driving pattern obtained from the vehicle actually running on the road. When measuring resistance, it is possible to control the intake pressure with good followability, and therefore the running resistance can be accurately measured.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a characteristic diagram showing an example of each command pattern. 1... Command generator, 2... Deviation device, 3... Control amplifier, 4... Adder, 5... Deviation device, 6... Control amplifier,
7... Operating device, 8... Position detector, 9... Intake pressure detector, 13... Vehicle speed detector, 14... Target vehicle, 18...
Chassis dynamometer, 19...torque detector,
20...Arithmetic unit, 21...Storage device.

Claims (1)

[Claims] 1. A command generator that generates command vehicle speed, command throttle opening, and command intake pressure according to each pattern of vehicle speed, throttle opening, and intake pressure obtained from actual running of the vehicle, and a command generator that generates the command intake pressure and the actual running on the bench. a control amplifier for amplifying the deviation from the intake pressure of the vehicle on the stand; an adder for adding the output of the control amplifier and the commanded throttle opening; and a detecting throttle opening of the vehicle on the stand. a detector that receives the output of the detector and the output of the adder as inputs and outputs an output that controls the throttle opening of the vehicle on the platform; a chassis dynamometer for controlling the vehicle speed of the vehicle; a computing unit for converting the torque generated by the chassis dynamometer to control the vehicle speed into running resistance; and a computing unit for converting the computing result of the computing unit to the commanded vehicle speed. A running resistance measuring device comprising a memory device for storing information.