CN110967190A

CN110967190A - Method for detecting maximum torque and power of engine by automobile bench test

Info

Publication number: CN110967190A
Application number: CN201911237398.XA
Authority: CN
Inventors: 吴明; 其他发明人请求不公开姓名
Original assignee: Liaoning Long Ma Antai Network Technology Co Ltd
Current assignee: Liaoning Long Ma Antai Network Technology Co Ltd
Priority date: 2019-11-26
Filing date: 2019-11-26
Publication date: 2020-04-07

Abstract

The method for detecting the maximum torque and the power of the engine in the bench test of the automobile comprises the steps of stepping the accelerator pedal of the automobile on the bench, reading the engine speed ni and the gearbox input shaft torque Mbi at the same time from the automobile OBD interface, and calculating the inertia torque Mj of the engine, i.e. Ie multiplied by Bi and the loss torque Mfi of engine accessories. When a dynamic detection mode is adopted, the loading force of a dynamometer and the inertia force of an automobile rack are used as loads for dynamic detection, the engine torque Mi of each rotating speed is calculated to be Mji + Mfi + Mbi and the power Pi, and the maximum torque and the maximum power of the engine can be obtained; alternatively, steady-state constant speed control detection is employed, with maximum torque Mm Mfm + Mbm and power detected at the engine maximum torque point, torque Me Mfe + Mbe and maximum power Pe detected at the rated power point, or when Mbi is read as a torque value on the engine crankshaft or a power value calculated from engine parameters, Mfi is set equal to 0.

Description

Method for detecting maximum torque and power of engine by automobile bench test

Technical Field

A method for detecting the maximum torque and power of an engine in a bench test of an automobile is a method for detecting the maximum torque and the maximum power of the engine by stepping an accelerator pedal to a rated power position on a chassis dynamometer and reading the opening degree of the accelerator pedal, the rotating speed of the engine and the torque of an input shaft of a gearbox through an OBD interface, and belongs to the technical field of the bench test detection of the performance of the automobile.

Background

The method for detecting the maximum torque and power of the automobile engine by bench test in the prior art is characterized in that the loading load of the dynamometer is measured on a chassis dynamometer of an automobile, the power of the engine is detected according to the balance between the driving force of the engine and the resistance of a system, the detection of the resistance of each part of the system is complex, along with the development of the automobile technology, the automobile is provided with various sensors including an engine torque sensor or a transmission input shaft torque sensor, and various sensor data can be timely transmitted through an OBD interface, and the method for detecting the maximum torque and power of the engine by bench test of the automobile fully utilizes the sensor of the automobile to detect, so that the defects in the prior art.

Disclosure of Invention

The output torque sensor of the automobile engine can be mounted in two ways, one way is that the output torque sensor is mounted on an engine crankshaft, the measured torque comprises the loss torque of an engine accessory, the other way is that the output torque sensor is mounted on an input shaft of a gearbox, the measured torque does not comprise the loss torque of the engine accessory and the loss torque of a hydraulic torque converter, and most of the existing automobiles adopt the latter mounting method. The engine output shaft of the non-hydraulic transmission automobile is in transmission connection with the gearbox input shaft in a ratio of 1: 1, the rotational inertia Ie of the engine is a fixed value, and the rotational inertia of the engine, the torque of engine accessories and a regression equation of the engine rotating speed can be obtained through tests.

A method for testing the maximum torque and power of engine in bench test includes reading the torque Mbi of input shaft of gear box, the rotation speed ni of engine and the speed Vi from OBD interface, calculating the angular acceleration Bi of rotation speed ni, the inertial torque Mji of rotation speed ni is Ie x Bi, calculating the loss torque Mfi of engine accessories according to the regression equation of loss torque of engine accessories and rotation speed of engine, obtaining the tested torque Mi of rotation speed ni Mji + Mfi + Mbi and the power Pi of engine is Mix ni/9549 in kW, and obtaining the maximum corrected torque and maximum power of engine by multiplying the maximum torque and maximum power of engine by power correction factor.

The chassis dynamometer can adopt a steady state detection mode or a dynamic detection mode, the steady state detection mode adopts constant speed control, the maximum torque of the engine is detected at the maximum torque rotating speed point of the engine or the corresponding vehicle speed point, the maximum power of the engine is detected at the rated rotating speed point of the engine or the corresponding vehicle speed point, and the inertia power of the engine is small and can be ignored because the rotating speed of the engine controlled by the constant speed is not changed greatly, and Mji is 0. The dynamic detection mode is to use the loading force of the dynamometer and the inertia force of the automobile rack as loads to carry out dynamic detection, the loading force of the dynamometer is smaller than the driving force of the driving wheels of the automobile, the roller of the automobile rack generates acceleration under the action of the driving force, the inertia power of the engine needs to be detected due to larger change of the rotating speed of the engine, and the maximum torque and the maximum power of the engine can be obtained by detecting the torque and the power of each point of the rotating speed of the engine.

The method for detecting the maximum torque and the maximum power of the engine in the bench test of the automobile is a method for reading sensor data through an OBD interface and detecting the maximum torque and the maximum power of the engine in the bench test, and is characterized in that: the method comprises the steps of hanging a specified gear of a gearbox on a chassis dynamometer, stepping an accelerator pedal of an automobile to a rated power position and stabilizing, reading an engine speed ni and a gearbox input shaft torque Mbi at the same moment from an OBD interface of the automobile, calculating an angular acceleration Bi and an engine inertia torque Mj of the engine speed ni point as Ie multiplied by Bi, wherein the Ie is the rotational inertia of the engine, calculating an engine accessory loss torque Mfi of the ni speed point, or counting the engine accessory loss torques of the engine rated torque speed point and the rated speed point; when a dynamic detection mode is adopted, the loading force of a dynamometer and the inertia force of an automobile rack are used as loads for dynamic detection, the engine torque Mi (Mji + Mfi + Mbi) and the engine power Pi (Mei × ni/9549) of each rotating speed point are calculated, and the maximum torque and the maximum power of the engine can be obtained in unit kW; or steady-state constant speed control detection is adopted, the maximum torque Mm of the engine is Mfm + Mbm and the power Pm is Mm multiplied by nm/9549 are detected at the maximum torque rotating speed point nm of the engine or the corresponding vehicle speed point Vm, the torque Me of the engine is Mfe + Mbe and the maximum power Pe is Me multiplied by ne/9549 are detected at the rated rotating speed point ne of the engine or the corresponding vehicle speed point Ve, the angle mark m corresponds to the maximum torque rotating speed point of the engine, and the angle mark e corresponds to the rated rotating speed point of the engine; or when the read Mbi is a torque value on the crankshaft of the engine output by the OBD or a power value calculated according to each parameter of the engine, setting the loss torque of the accessories of the engine to be equal to 0; or only one of the parameters of the maximum torque or the maximum power of the engine is detected as required.

Detailed Description

Taking a gasoline passenger car and a diesel truck provided with a transmission input shaft torque sensor as examples, a specific implementation mode of a method for detecting the maximum torque and the power of an engine by an automobile bench test is described, the automobile is provided with a transmission specified gear on a chassis dynamometer, an accelerator pedal is stepped to a rated power position and is stable, the engine speed ni and the transmission input torque Mbi at the same moment are read from an automobile OBD interface, the angular acceleration Bi and the engine inertia torque Mji of an engine speed ni point are calculated to be Ie multiplied by Bi, the Ie is the engine rotational inertia, and the engine accessory loss torque Mfi of the ni speed point is calculated.

Because the rated rotating speed of the gasoline engine is higher, most running conditions are in the rotating speed range near the maximum torque rotating speed nm and less than nm, and the maximum torque or the maximum torque power can be detected to judge and evaluate the dynamic property of the automobile. In order to reduce the detection time of large load and high speed, a dynamic detection method is adopted, dynamometer loading force and automobile platform inertia force are used as loads for dynamic detection, the engine torque Mi of each rotating speed point is Mji + Mfi + Mbi, the engine power Pi of each rotating speed point is Mei multiplied by ni/9549, and the unit kW is obtained, so that the maximum torque and the maximum power of the engine can be obtained.

Because the rated rotating speed of the diesel engine is lower, most running conditions are in the rotating speed range near the maximum rotating speed ne and less than ne, and the maximum power can be detected to judge and evaluate the dynamic property of the automobile. After the vehicle speed point Ve with the rated engine power is determined, steady-state Ve constant speed control detection is adopted, and engine torque Me & ltMfe + Mbe and maximum power Pe & ltMe & gtne/9549 are detected.

Whether the vehicle is a gasoline vehicle or a diesel vehicle, the maximum torque and the maximum power of the engine can be detected by adopting a dynamic detection mode or a steady-state detection mode. When the read Mbi is a torque value on the crankshaft of the engine or a power value calculated according to each parameter of the engine output by the OBD, the engine accessory loss torque is set to be equal to 0. According to the detection requirement, only one parameter of the maximum torque or the maximum power of the engine can be detected. The detected value is corrected to obtain the corrected maximum torque and the corrected maximum power under the standard environmental state, and the corrected maximum torque and the corrected maximum power can be respectively compared with the rated torque or the rated power of the engine specification, so that the engine dynamic property of the detected automobile is evaluated.

The method for detecting the maximum torque and the power of the engine by the bench test of the automobile reads the data of the automobile sensor of the OBD to detect the dynamic property, and has the advantages of simplicity, convenience, accuracy, rapidness and the like.

Claims

1. The method for detecting the maximum torque and the maximum power of the engine in the bench test of the automobile is a method for reading sensor data through an OBD interface and detecting the maximum torque and the maximum power of the engine in the bench test, and is characterized in that: the method comprises the steps of hanging a specified gear of a gearbox on a chassis dynamometer, stepping an accelerator pedal of an automobile to a rated power position and stabilizing, reading an engine speed ni and a gearbox input shaft torque Mbi at the same moment from an OBD interface of the automobile, calculating an angular acceleration Bi and an engine inertia torque Mj of the engine speed ni point as Ie multiplied by Bi, wherein the Ie is the rotational inertia of the engine, calculating an engine accessory loss torque Mfi of the ni speed point, or counting the engine accessory loss torques of the engine rated torque speed point and the rated speed point; when a dynamic detection mode is adopted, the loading force of a dynamometer and the inertia force of an automobile rack are used as loads for dynamic detection, the engine torque Mi (Mji + Mfi + Mbi) and the engine power Pi (Mei × ni/9549) of each rotating speed point are calculated, and the maximum torque and the maximum power of the engine can be obtained in unit kW; or steady-state constant speed control detection is adopted, the maximum torque Mm of the engine is Mfm + Mbm and the power Pm is Mm multiplied by nm/9549 are detected at the maximum torque rotating speed point nm of the engine or the corresponding vehicle speed point Vm, the torque Me of the engine is Mfe + Mbe and the maximum power Pe is Me multiplied by ne/9549 are detected at the rated rotating speed point ne of the engine or the corresponding vehicle speed point Ve, the angle mark m corresponds to the maximum torque rotating speed point of the engine, and the angle mark e corresponds to the rated rotating speed point of the engine; or when the read Mbi is a torque value on the crankshaft of the engine output by the OBD or a power value calculated according to each parameter of the engine, setting the loss torque of the accessories of the engine to be equal to 0; or only one of the parameters of the maximum torque or the maximum power of the engine is detected as required.