JPH08278232A - Setting method of mechanical loss in chassis dynamometer - Google Patents

Abstract

PURPOSE: To obtain a setting method in which the running state of a vehicle can be reproduced so as to be similar to its actual running operation up to a warming-up state from a cold start by a method wherein mechanical loss data is read out selectively according to the bearing temperature of a dynamometer. CONSTITUTION: A vehicle and a dynamometer are cold-started, and the damping force of the dynamometer including a roller is measured while a vehicle speed is being changed. Thereby, mechanical loss data with reference to the vehicle speed is measured in the bearing temperature series of the dynamometer so as to be stored. That is to say, the mechanical loss data between a temperature T2 and a temperature T1 , between a temperature T3 and the temperature T2 ,... between a temperature Tm and a temperature Tm-1 is stored in the form of a memory table. The bearing temperature T of the dynamometer is measured by an exhaust gas measuring test or the like from a cold start. When the temperature T <= the temperature Tm , the mechanical loss data between the temperature Tm and the temperature Tm-1 is read out of a memory. When the temperature T>(the maximum value of the temperature Tm ), the mechanical loss data between the maximum value of the temperature Tm and the temperature Tm-1 before it is read out of the memory.

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 carrying out a fuel consumption measurement test and an exhaust gas certification test for automobiles, and more particularly to a method for setting a mechanical loss when a vehicle is cold started.

[0002]

2. Description of the Related Art Generally, in a chassis dynamometer, as shown in FIG. 1, for example, in the case of a front-wheel drive vehicle, a drive wheel (front wheel) 1a of a vehicle 1 is placed on a rotatable roller 2, and The rear wheel 1b is fixed, and the front and rear portions of the vehicle body 1c are fixed to the fixed portion via the wires 3 and 4,
The dynamometer 3 was connected to the roller 23. Then, the vehicle 1 is driven, and this driving force is absorbed by the dynamometer 3 via the roller 1 to carry out tests for fuel consumption measurement and exhaust gas measurement. In this case, it is necessary to create a state equivalent to that of the vehicle 1 traveling on the road, and it is necessary to recognize the same load (driving resistance) as on the road.

FIG. 2 shows the relationship between the vehicle speed and the braking force of the dynamometer 3 including the roller 2. In setting the load, first, the mechanical loss of the vehicle 1 and the mechanical loss of the dynamometer 3 (including the roller 2) are summed. Measured Mechaloss ML,
The value obtained by subtracting the mechanical loss ML from the target running resistance RL is taken as the absorbing power of the dynamometer 3 including the roller 2, and the load is set so that the dynamometer 3 exhibits such absorbing power. That is, when the absorbing power of the dynamometer 3 including the roller 2 is Fp, the load is set as Fp = RL-ML. Further, the vehicle 1 is sufficiently warmed up when measuring the mechaloss ML.

[0004]

By the way, in the exhaust gas measurement test of the vehicle 1, there is a test in which the vehicle 1 and the dynamometer 3 are cold-started from a cooling state, but in a state in which the vehicle 1 and the dynamometer 3 are cold and sufficiently warmed up. If the mechanical loss is different and ML _C is the cold mechanical loss and ML _H is the fully warmed mechanical loss, then ML _C > ML _H. Therefore, if the mechanical loss when warmed up sufficiently is used when the vehicle 1 and the dynamometer 3 are in a cold state, the mechanical loss is smaller than the actual value, and therefore the absorption power of the dynamometer 3 including the roller 2 is set to a value larger than necessary. The vehicle 1
The running resistance applied to the vehicle was also set higher than that when driving on the road, and the exhaust gas measurement values became inaccurate.

That is, in the exhaust gas measurement test, the vehicle 1 and the dynamometer 3 gradually enter a stable state as the temperature rises from the start, and the mechanical loss also gradually becomes stable as the bearing temperature of the dynamometer 3 rises as shown in FIG. Then, when it is used for the value in this stable state, it becomes as described above, and the measured value of exhaust gas becomes inaccurate.

The present invention has been made in order to solve the above problems, and can reproduce the same conditions as during actual running of a vehicle from cold start to warm-up, such as exhaust gas measurement tests. It is an object of the present invention to obtain a mechanical loss setting method in a chassis dynamometer that can accurately perform.

[0007]

A mechanical loss setting method for a chassis dynamometer according to the present invention comprises cold starting a vehicle and a dynamometer, and measuring a braking force of a dynamometer including a roller 2 while changing a vehicle speed. The mechanical loss data with respect to the vehicle speed is measured and stored by the temperature series of the bearing temperature of the dynamometer, and the mechanical loss data is selectively read according to the bearing temperature of the dynamometer from the cold start.

[0008]

According to the present invention, the vehicle and the dynamometer are cold-started, and the braking force of the dynamometer including the rollers is measured while changing the vehicle speed, so that the mechanical loss data with respect to the vehicle speed is obtained as a temperature series of the bearing temperature of the dynamometer. The mechanical loss data measured and stored in accordance with the bearing temperature of the dynamometer from the cold start is selectively read out.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 4 is a flow chart showing the procedure for measuring and storing the mechanical loss data in the chassis dynamometer according to this embodiment. The vehicle 1 and the dynamometer 3 are brought into a cold state in step S1, and the vehicle 1 is set on the roller 2 in step S2. . In step S3, the vehicle 1 is driven and speed control is performed by the dynamometer 3 to increase or decrease the vehicle speed from 0 to V _{n in} several steps as shown in FIG. Step In S4, as shown in FIG. 5 (b) measuring the braking force of the dynamometer 3 including roller 2 in this vehicle speeds, which is referred to as mechanical loss ML ₁ ~ML _n. In step S5, the mechanical losses ML _{1 to} ML _n are kept at a certain temperature interval in the bearing temperature of the dynamometer 3 from the cold start to the temperature T ₁ , between the temperatures T _{2 to} T ₁ , and the temperature T ₃ to.
The mechanical loss data between T ₂ and T _{m to} T _m-1 is set as shown in FIG. 6 and stored in a memory in a table format. In step S6, it is determined whether or not the procedure as described above has been performed the specified number of times, and if the specified number of times has been performed, the flow ends. The braking force is calculated from the mass and acceleration of the dynamometer 3 and the roller 2.

FIG. 7 is a flow chart showing a mechanical loss setting procedure at the cold start in an exhaust gas measurement test or the like. In step S7, the bearing temperature T of the dynamometer 3 is measured from the cold start, and step S8 is performed.
Then, when T ≦ T _m , the mechanical loss data of T _{m to} T _m-1 shown in FIG. 6 is read from the memory. In step S9, T
In the case of> (maximum value of T _m ), the mechanical loss data between the maximum value of T _m and the temperature T _m−1 before that is read from the memory.

Next, the mechanical loss ML read from the target running resistance RL is subtracted to determine the absorbing power of the dynamometer 3 including the roller 2, and the dynamometer 3 is controlled so that the determined absorbing power is obtained. .

In the above embodiment, the mechanical loss data is measured and stored in a temperature series from the cold start of the vehicle 1 and the dynamometer 3, and the mechanical loss data is sequentially read and set according to the temperature rise from the cold start. Since the mechanical loss can be set accurately from the cold state to the warm-up state, the vehicle can be driven under the same conditions as in actual driving, and exhaust gas measurement etc. can be performed exactly as in actual driving. be able to.

[0013]

As described above, according to the present invention, the mechanical loss data is measured and stored in a temperature series from the cold start of the vehicle and the dynamometer, and the mechanical loss data is sequentially read from the cold start according to the temperature rise. The mechaloss can be set accurately from the cold state to the warm-up state, and the cold start vehicle can be run under the same conditions as when actually running,
Exhaust gas measurement tests can be performed accurately.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a chassis dynamometer.

FIG. 2 is a braking force characteristic diagram of a dynamometer.

FIG. 3 is a variable diagram of a mechanical loss from a cold start with respect to a dynamometer bearing temperature.

FIG. 4 is a flowchart showing a procedure for measuring and storing mechanical loss in the chassis dynamometer according to the present invention.

FIG. 5 is a diagram showing a change in vehicle speed when measuring a mechanical loss in the chassis dynamometer according to the present invention, and an enlarged view of a portion A thereof.

FIG. 6 is temperature series mechanical loss data in the chassis dynamometer according to the present invention.

FIG. 7 is a flowchart showing a mechanical loss reading procedure in the chassis dynamometer according to the present invention.

[Explanation of symbols]

 1 ... Vehicle 1a ... Drive wheel 2 ... Roller 3 ... Dynamometer

Claims (1)

[Claims] 1. A chassis dynamometer in which a driving wheel of a vehicle is placed on a rotatable roller and a dynamometer is connected to the roller so that the driving force of the driving wheel of the vehicle is absorbed by the dynamometer. Start the vehicle and the dynamometer from a cold state, measure the braking force of the dynamometer including the rollers while changing the vehicle speed to measure the mechanical loss data for the vehicle speed in the temperature series of the bearing temperature of the dynamometer, and store it. A mechanical loss setting method for a chassis dynamometer, characterized in that the mechanical loss data is selectively read according to the bearing temperature of the dynamometer from the cold start.