CN113237590B

CN113237590B - Method for detecting maximum torque of engine without external load

Info

Publication number: CN113237590B
Application number: CN202110563028.6A
Authority: CN
Inventors: 朱卫萍
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-05-15
Filing date: 2021-05-15
Publication date: 2023-01-13
Anticipated expiration: 2041-05-15
Also published as: CN113237590A

Abstract

The method for detecting the maximum torque of the engine without external load comprises the steps that the same automobile detects the steady-state maximum torque Mw of the engine on a chassis dynamometer, the steady-state oil consumption Qw is set, the dynamic maximum torque Md of the engine is detected without external load, the dynamic oil consumption Qd is set, qd = Qw + Qf, and Qf is additional oil consumption; the mechanical loss torque Mg of the engine is set as a constant, steady-state and dynamic detection torques of the same automobile are set to be proportional to oil consumption, and the constant (Qw + Qf)/Qw = (Md + phi xMm)/(Mw + phi xMm), and the constant Qf/Qw = (Md + phi xMm)/(Mw + phi xMm) -1C is set to be the same, and when any automobile of the automobile type detects the dynamic maximum torque Md of the engine without external load, the corresponding steady-state maximum torque Mw of the engine can be calculated.

Description

Method for detecting maximum torque of engine without external load

Technical Field

A method for detecting the maximum torque of an engine without external load is a quick method for detecting the maximum torque of the engine by taking the inertia of the engine as the load when a gearbox of an automobile is in neutral gear and the engine has no external load, and belongs to the technical field of automobile performance detection.

Background

The existing automobile needs to detect the maximum torque of an engine on a chassis dynamometer or a road test, and the required equipment is expensive, long in detection time and high in cost. The existing no-load power measuring method can not accurately detect the maximum torque of the engine, and only detects the acceleration time respectively before and after the repair shop repairs the automobile to compare the time. With the development of automobile technology, many passenger cars have an additional fuel supply to the engine during acceleration, which increases the dynamic maximum torque of the engine without external load detection. In order to overcome the defects of the prior art, a method for detecting the maximum torque of the engine without external load is adopted, and the dynamic maximum torque of the engine can be converted into the steady-state maximum torque of the engine by establishing a functional relation between the steady-state and the dynamic maximum torque of the engine, and compared with the rated torque indicated by an engine specification, the reduction degree of the technical condition of the engine is quantitatively evaluated.

Disclosure of Invention

In many electric injection engine passenger vehicles, no matter when the electric injection engine passenger vehicles are running or when no external load detection torque exists, short-time additional oil supply amount is available in the process of stepping on an accelerator pedal to accelerate, additional power is provided to meet the requirement of an acceleration working condition, the maximum torque of the engine without external load detection is larger than the rated torque of the engine, and the reduction degree of the technical condition of the engine cannot be accurately detected and evaluated. Therefore, according to the characteristics of the electronic fuel injection oil supply amount controlled by a computer, a functional relation between the steady state and the dynamic engine maximum torque is deduced through the relation between the steady state oil supply amount and the steady state maximum torque and the relation between the additional oil supply amount and the dynamic maximum torque, so that the dynamic maximum torque measured by the additional oil supply amount is converted into the steady state maximum torque without the additional oil supply amount.

At the engine maximum torque point, the engine indicated torque Mz is equal to the sum of the engine mechanical loss torque Mg and the rated torque Mm, mz = Mg + Mm, mg = δ × Mz, δ is the engine mechanical loss coefficient, mz = δ × Mz + Mm, mz = Mm/(1- δ), mg = δ × Mz = δ × Mm/(1- δ), δ/(1- δ) = Φ is set as the engine mechanical loss calculation coefficient, mg = Φ × Mm, Φ is also a known quantity when δ is known, and can also be determined by direct estimation.

The steady state maximum torque Mw of the engine of the same automobile is detected on a chassis dynamometer, steady state oil consumption Qw is set, no external load is used for detecting the dynamic maximum torque Md of the engine, dynamic oil consumption Qd is set, and Qd is equal to the sum of the steady state oil consumption Qw and additional oil consumption Qf, namely Qd = Qw + Qf. After the technical condition of the engine is reduced, neglecting the change of the mechanical loss torque of the engine, setting Mg to be unchanged, setting the maximum torque of the engine detected in the steady state and the dynamic state of the same automobile to be in direct proportion to the oil consumption, (Qw + Qf)/Qw = (Md + phi xMm)/(Mw + phi xMm), qf/Qw = (Md + phi xMm)/(Mw + phi xMm) -1= -C, wherein phi, md, mw and Mm are known quantities, qf/Qw is equal to a fixed value C, and Qf/Qw = C of all automobiles of the automobile type, so that the functional relation between the maximum torque of the engine detected in the steady state and the maximum torque of the engine detected in the dynamic state of all automobiles of the automobile type is established, the Mw does not need to be detected again, and when the maximum torque Md of the engine detected in the dynamic state without external load is adopted, the corresponding maximum torque in the steady state of the engine can be calculated.

The method for detecting the maximum torque of the engine without external load is a detection method which calibrates the maximum torque of the engine by steady-state and dynamic detection, converts the dynamic torque into the steady-state torque after establishing a function relation of two torque values, and is characterized in that: the method comprises the following steps that the same automobile detects the steady-state maximum torque Mw of an engine on a chassis dynamometer, or simplifies the process without bench test detection, uses the rated torque Mm of the engine to replace the Mw for detecting a new automobile, sets steady-state oil consumption Qw, adopts no external load to detect the dynamic maximum torque Md of the engine, sets dynamic oil consumption Qd, wherein Qd = Qw + Qf, and Qf is additional oil consumption; the mechanical loss torque Mg of the engine is set as a constant, the steady-state and dynamic detection torques of the same automobile are set to be proportional to the oil consumption, (Qw + Qf)/Qw = (Md + phi x Mm)/(Mw + phi x Mm), qf/Qw = (Md + phi x Mm)/(Mw + phi x Mm) -1= C constant, phi is a mechanical loss calculation coefficient of the engine, or phi =0 is simplified, a constant C is obtained through calibration, the Qf/Qw = C of all automobiles of the automobile type is set to be the same, and when any automobile of the automobile type adopts the no external load to detect the dynamic maximum torque Md of the engine, the corresponding steady-state maximum torque of the engine can be calculated. Has the following technical advantages.

1. The electronic fuel injection oil supply is controlled by a computer, so that the steady-state oil supply of all the automobiles of the same automobile type is basically the same, and the additional oil supply under the same acceleration working condition without external load detection is also basically the same.

2. The ratio of the mechanical loss torque Mg of the engine to the rated torque is small, the technical condition of the engine is reduced, and the influence of the increased value of Mg on detection is small and can be ignored.

3. Although the ratio of the maximum torque to the oil consumption of the engine detected in the steady state and the dynamic state has a certain difference, the similar proportion of different automobiles of the same automobile type is basically the same, and the influence of the difference on the detection can be ignored.

4. The method can simplify the measurement of the maximum torque Mw of the steady-state engine without bench test, replace Mw with the rated torque Mm of a new vehicle engine, and finish calibration by detecting Md without external load.

Detailed Description

The specific implementation of the method for detecting the maximum torque of the engine without external load is described by taking a passenger car without external load detection and with additional oil supply in the acceleration process as an example. The rated torque Mm =141Nm of the engine, delta =0.1, phi = delta/(1-delta) =0.111, and under the same detection environment, the steady-state maximum torque Mw =129.1Nm of the engine is detected on a chassis dynamometer, and the maximum torque Md =181.8Nm of the engine is detected by adopting no external load. Qf/Qw = (Md + Φ × Mm)/(Mw + Φ × Mm) -1= (181.8 +0.111 × 141)/(129.1 +0.111 × 141) -1=0.364= C.

Mw = (Md + Φ × Mm)/1.364- Φ × Mm = (Md +0.111 × 141)/1.364-0.111 × 141= (Md + 15.65)/1.364-15.65, and another automobile of the same model is tested 3 times without external load, and calculated as follows:

md1=171.1, mw1=121.3, torque ratio value Mw1/Mm =121.3/141=0.860;

md2=175.7, mw2=124.6, torque ratio value Mw2/Mm =124.6/141=0.884;

md3=168.4, mw3=119.3, torque ratio value Mw3/Mm =119.3/141=0.846.

The method for detecting the maximum torque of the engine without external load greatly improves the accuracy of detecting the maximum torque of the engine without external load with additional oil supply, and has the advantages of accuracy, rapidness and the like.

Claims

1. The method for detecting the maximum torque of the engine without external load is a detection method which is characterized in that the maximum torque of the engine is calibrated by steady-state and dynamic detection, and after a functional relation of two torque values is established, the dynamic torque is converted into the steady-state torque, and the method is characterized in that: the method comprises the following steps that the same automobile detects the steady-state maximum torque Mw of an engine on a chassis dynamometer, or simplifies the process without bench test detection, uses the rated torque Mm of the engine to replace the Mw for detecting a new automobile, sets steady-state oil consumption Qw, detects the dynamic maximum torque Md of the engine by adopting no external load, sets dynamic oil consumption Qd, qd = Qw + Qf, and Qf is additional oil consumption; the method comprises the steps of setting mechanical loss torque Mg of an engine as a constant, setting steady-state and dynamic detection torques of the same automobile to be proportional to oil consumption, (Qw + Qf)/Qw = (Md + phi x Mm)/(Mw + phi x Mm), qf/Qw = (Md + phi x Mm)/(Mw + phi x Mm) -1= (Md + phi x Mm)/(Mw + phi x Mm) -C constant, setting phi to be a mechanical loss calculation coefficient of the engine, setting phi = delta/(1-delta), and setting delta to be the mechanical loss coefficient of the engine, or simplifying and setting phi =0, obtaining the constant C through calibration, setting Qf/Qw = C of all automobiles of a model to be the same, and obtaining the corresponding steady-state maximum torque Mw of the engine after any automobile of the model adopts no external load to detect the dynamic maximum torque Md of the engine.