CN102662073A - Detection Method of Loading Deceleration Engine Speed - Google Patents

Abstract

The loaded deceleration engine speed detection method measures the vehicle speed to convert the corresponding engine speed. First, the vehicle speed Ve corresponding to the rated engine speed in the manual of the specified gear position of the inspected vehicle is determined. When the vehicle speed Vi is measured, the weight coefficient Ki=Vi/Ve is obtained, and the engine speed ni corresponding to Vi is calculated. Regardless of whether the logged-in engine rated speed is correct, the weight coefficient Ki can be used to accurately evaluate the ratio of the engine speed corresponding to the specified speed point to the rated engine speed in the manual. There is no need to install an engine tachometer sensor to measure the engine speed, which greatly improves the accuracy and operability. It is suitable for the inspection station to detect and evaluate the engine speed of many in-use vehicle models.

Description

Detection Method of Loading Deceleration Engine Speed

technical field

The invention relates to a detection method for engine speed under load and deceleration, which is a detection method for converting vehicle speed into engine speed when a diesel vehicle is loaded and decelerated on a chassis dynamometer to detect exhaust emissions, and belongs to the technical field of automobile performance bench test detection methods.

Background technique

In order to ensure that the technical parameters of the diesel engine used for loading and decelerating exhaust emission detection are normal, and to prevent the throttle from being too small or the fuel supply volume from being too small, not only the limited value of the wheel power, but also the limited value of the engine speed are required. The existing technology requires measurement Generator speed at each speed point. Using an engine tachometer to measure the speed of a diesel engine has a contradiction between operability and accuracy. If an engine tachometer with high accuracy is used for measurement, the operability of installing a tachometer sensor is very poor; if an adsorption sensor with better operability is used Vibration sensors have poor detection accuracy. In testing practice, it is often difficult to know the rated speed of the diesel engine in the manual of the inspected vehicle, and it is easy to input the wrong rated speed, resulting in a large number of wrong detections and judgments of the engine speed. Therefore, in order to overcome the deficiencies of the prior art, an innovative method for detecting the speed of the engine under load and deceleration is adopted to greatly improve the accuracy and operability of the detection of the engine speed.

Contents of the invention

The test statistics show that when different models of the same model series are in direct gear or the closest gear with a transmission ratio of 1, although the rated engine speed varies greatly, the difference in vehicle speed corresponding to the rated engine speed is small. Set the rated engine speed of the inspected vehicle of a certain model series as ne, and the vehicle speed corresponding to the direct gear of the gearbox or the transmission ratio close to the first gear is Ve. The ratio of measured engine speed to vehicle speed can be calibrated for a specific model and stored in the computer, and it will be called automatically when the same model is detected. Assuming that the ratio of the engine speed to the vehicle speed is K=ne/Ve, when the measured vehicle speed is Vi, the corresponding engine speed ni=Vi×K=Vi×ne/Ve. If you do not know the rated engine speed ne, and input the wrong engine rated speed nc when logging in, you will get the wrong ratio Kc=nc/Ve. When the measured vehicle speed is the same as Vi, you will get the wrong corresponding engine speed nic=Vi× Kc=Vi×nc/Ve. If ni/ne=nic/nc=Vi/Ve=Ki, Ve is a definite value for a specific vehicle to be inspected, and Ki is obtained by obtaining the measured value Vi, and Ki is linearly proportional to Vi. ni=Ki×ne, nic=Ki×nc. It can be concluded that if the wrong engine rated speed is input, the calculated engine speed value will have an error relative to the input of the correct engine rated speed, but the ratio of the wrong engine speed to the wrong engine rated speed does not change, Ki and It has nothing to do with the correctness of the rated speed of the engine in the registration manual. The engine speed limit required by the current standard is the ratio of the engine speed to the rated speed of the registered engine. Then the measurement process uses Ki to convert the instantaneous engine speed nic=Ki×nc to accurately measure the engine speed The measurement and evaluation of the weight coefficient of the rated speed relative to the specification. The engine speed is measured according to the requirements of the current standard, and the engine speed can be measured without installing the engine tachometer sensor. After the vehicle speed is measured, the weight coefficient is used to convert the engine speed, which greatly improves the accuracy and operability of the detection.

The engine speed detection method of loading and deceleration is a method of converting the vehicle speed into the engine speed when the diesel vehicle is loaded and decelerated on the chassis dynamometer to detect exhaust emissions in a specified gear. It is characterized in that Ve is accurately determined according to vehicle model parameters or calculated according to model series statistics or stored in the computer according to calibration and automatically called. Ve is the vehicle speed corresponding to the rated engine speed ne of the diesel vehicle's specified gear specification, and the Ve of different gearbox gears is different. . When the measured vehicle speed is Vi, the corresponding engine speed is ni, let ni/ne=Vi/Ve=Ki, ni=Ki×ne, Ki is the weight coefficient of ni relative to ne, and Ki is linearly proportional to Vi, regardless of the input ne Whether it is correct, the ratio ni/ne=Vi/Ve remains unchanged, there is no need to install the engine tachometer sensor to measure the engine speed, and the engine speed corresponding to the vehicle speed can be calculated according to the measured vehicle speed Vi, and the ratio ni/ne is obtained. When the engine speed The evaluation index is the ratio of the engine speed corresponding to the specified state vehicle speed point to the engine rated speed in the manual, and it is accurately evaluated according to the weight coefficient. If it is not required to measure the generator speed at each speed point, but only to evaluate the ratio of the engine speed corresponding to a specified speed point to the rated engine speed in the manual, or only to evaluate the ratio between a specified state speed point and the reference speed, then it is not necessary to measure the vehicle speed. Converted to the engine speed, Ve is set as the reference vehicle speed, and evaluated by the weight coefficient Ki of the vehicle speed point in the specified state. The advantages of the load deceleration engine speed detection method are as follows:

1. There is no need to install the sensor of the engine tachometer, which greatly improves the detection efficiency, accuracy and operability.

2. The measurement accuracy of the vehicle speed is much higher than that of the vehicle-mounted engine speed measurement accuracy. By converting the vehicle speed to the engine speed, the fluctuation and error of the engine speed measurement value can be greatly reduced.

3. Even if the engine rated speed in the manual is incorrectly registered, it can still accurately calculate the ratio of the engine speed corresponding to the speed point in the specified state to the rated engine speed in the manual, and it can be accurately judged without misjudgment. Speed detection and evaluation.

4. The error of determining Ve is much smaller than the measurement error of the adsorption vibration tachometer.

5. The engine speed value can be calculated, and the engine speed can also be recorded by the weight coefficient of the rated engine speed in the manual.

Detailed ways

Taking the exhaust emission detection of a certain type of passenger car in the 6100 model series as an example to illustrate the specific implementation of the method for detecting the engine speed during loading and deceleration:

1. If Ve is determined according to the model series statistics of the national standard GB18565-2001 "Comprehensive Performance Requirements and Inspection Methods for Commercial Vehicles", get Ve = 85km/h from the direct gear rated power reference speed in Table 1, and register the correct engine rating in the manual. The speed is 2400r/min.

2. When the measured vehicle speed Vi=75km/h, the corresponding engine speed ni=75×2400/85=2118r/min. The steady-state measured vehicle speed at the maximum wheel power of the direct gear is 72.6km/h, and the corresponding engine speed n _72.6 =72.6×2400/85=0.854×2400=2050r/min. If you do not know the rated engine speed in the manual of the passenger car, you can arbitrarily log in the rated engine speed ne in the manual, n _72.6 = 72.6 x ne/85 = 0.854 x ne, and use the weight coefficient of the rated engine speed in the manual to record the engine speed.

3. According to the provisions of J.4.5.5 of the national standard GB3847-2005 "Vehicle Compression Ignition Engine and Compression Ignition Engine Vehicle Exhaust Smoke Emission Limits and Measurement Methods": when the engine speed corresponding to the maximum wheel power speed Compare it with the engine's calibrated speed specified by the engine manufacturer, if it exceeds the calibrated speed by ±10%, the vehicle will be considered unqualified and failed. Then the ratio of the engine speed n _72.6 to the rated engine speed ne in the manual is 72.6/85=0.854, and the evaluation is unqualified. If it is not necessary to measure the engine speed, but only evaluate the ratio of the engine speed at the maximum wheel power speed point to the rated engine speed in the manual, or only evaluate the ratio of a specified state speed point to the reference speed, then Ve can be set as the reference speed. The weight coefficient Ki=72.6/85=0.854 of the maximum wheel power vehicle speed point is used for evaluation.

3. Use a relatively accurate engine tachometer to synchronously measure the engine speed at the maximum wheel power speed point to be 2012r/min, and the error is (2050-2012)/2012=1.9%.

The method for detecting the rotational speed of the engine with loading and deceleration has the advantages of accuracy, simplicity and quickness, which greatly reduces the misdetection and misjudgment of the rotational speed of the engine, and improves the accuracy and operability.

Claims (1)

1. Loading and deceleration engine speed detection method is a method of converting the vehicle speed into engine speed when the diesel vehicle is loaded and decelerated on the chassis dynamometer to detect exhaust emissions in the specified gear. It is characterized in that Ve is accurately determined according to vehicle model parameters or calculated according to model series statistics or stored in the computer according to calibration and automatically called. Ve is the vehicle speed corresponding to the rated engine speed ne of the diesel vehicle's specified gear specification, and the Ve of different gearbox gears is different. . When the measured vehicle speed is Vi, the corresponding engine speed is ni, let ni/ne=Vi/Ve=Ki, ni=Ki×ne, Ki is the weight coefficient of ni relative to ne, and Ki is linearly proportional to Vi, regardless of the input ne Whether it is correct, the ratio ni/ne=Vi/Ve remains unchanged, there is no need to install the engine tachometer sensor to measure the engine speed, and the engine speed corresponding to the vehicle speed can be calculated according to the measured vehicle speed Vi, and the ratio ni/ne is obtained. When the engine speed The evaluation index is the ratio of the engine speed corresponding to the specified state vehicle speed point to the engine rated speed in the manual, and it is accurately evaluated according to the weight coefficient. If it is not required to measure the generator speed at each speed point, but only to evaluate the ratio of the engine speed corresponding to a specified speed point to the rated engine speed in the manual, or only to evaluate the ratio between a specified state speed point and the reference speed, then it is not necessary to measure the vehicle speed. Converted to the engine speed, Ve is set as the reference vehicle speed, and evaluated by the weight coefficient Ki of the vehicle speed point in the specified state.