JP2011226853A - Combustion noise evaluation method and combustion noise evaluation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quantitatively evaluate combustion noise at acceleration of an internal-combustion engine.SOLUTION: Accumulated fuel consumption from the start of acceleration of an internal-combustion engine and a sound pressure of combustion noise are sampled at a plurality of time points from the start to the end of the acceleration, and according to a time series Pof the sampled values an approximate straight line L is calculated which approximates the relationship between the accumulated fuel consumption and the sound pressure from the start to the end of the acceleration. Based on the inclination of the approximate straight line and the variability of the standard deviation of the differences between the approximate straight line and the sampled values, the linearity of the increase of combustion noise at acceleration is evaluated.

Description

  The present invention relates to a method for quantitative evaluation of combustion noise during acceleration of an internal combustion engine.

  It is desirable that the combustion noise during acceleration of the internal combustion engine increase linearly without sudden increase or hunting (see, for example, the following patent document).

  Conventionally, evaluation of combustion noise of an internal combustion engine relies exclusively on human hearing and sensuality, and no quantitative index exists.

JP 2005-315077 A

  The present invention seeks to establish a method for quantitatively evaluating combustion noise during acceleration of an internal combustion engine.

  In the present invention, the cumulative amount from the start of acceleration of the fuel consumption at a plurality of time points in the period from the start of acceleration to the end of acceleration of the internal combustion engine, and the sound pressure of the combustion noise at each time point are sampled and measured. From the time series, the approximate straight line that approximates the relationship between the accumulated fuel consumption and the sound pressure in the period from the start of acceleration to the end of acceleration is calculated, the slope of the approximate straight line, and the approximate straight line and the sampling value The combustion noise during acceleration was evaluated based on the variance of the residual and the standard deviation of the residual.

  With such a configuration, it is possible to quantitatively evaluate the degree of linearity of the increase in the sound pressure of the combustion noise during acceleration of the internal combustion engine, that is, the linear feeling given to the driver.

  The evaluation device used for evaluating the combustion noise at the time of acceleration of the internal combustion engine is a cumulative amount from the start of acceleration of fuel consumption at a plurality of time points in the period from the start of acceleration to the end of acceleration of the internal combustion engine, and A measurement unit that samples and measures the sound pressure of combustion noise at each time point, and an approximate straight line that approximates the relationship between the accumulated fuel consumption and sound pressure within the period from the start of acceleration to the end of acceleration based on the time series of sampling values And an evaluation value output unit for outputting the slope of the approximate line and the variance of the residual between the approximate line and the sampling value or the standard deviation of the residual. Here, the output is a concept including writing to a memory or other recording medium, display on a display, printing, and transmission to an external device.

  According to the present invention, combustion noise during acceleration of an internal combustion engine can be quantitatively evaluated.

1 is a schematic overall configuration diagram of an internal combustion engine according to an embodiment of the present invention. The hardware resource block diagram of the combustion noise evaluation apparatus of the embodiment. The functional block diagram of the combustion noise evaluation apparatus. The figure explaining the content of the combustion noise evaluation method of the embodiment.

  An embodiment of the present invention will be described with reference to the drawings. As an example of the internal combustion engine, a schematic configuration of a diesel engine (compression ignition engine) 0 will be described. As schematically shown in FIG. 1, a diesel engine 0 mounted on a vehicle or the like has a plurality of cylinders 7 (only one cylinder is drawn in FIG. 1) and fuel in each cylinder 7. A variable combination of an injector 73 for injection, an intake system path 3 for supplying intake air to each cylinder 7, an exhaust system path 4 for discharging exhaust gas from each cylinder 7, a drive turbine 22 and a compressor 21. A capacity turbocharger 2 and an EGR device 5 that recirculates exhaust gas through the intake path 3 and the exhaust path 4 are provided.

  The intake system path 3 takes in air from the outside and guides it to the intake port 71 of the cylinder 7. On the intake path 3, an air cleaner 31, a compressor 21, an intercooler 32, and a surge tank 33 are arranged in this order from the upstream.

  The exhaust system path 4 guides exhaust gas generated as a result of burning fuel in the cylinder 7 from the exhaust port 72 of the cylinder 7 to the outside. A drive turbine 22 is disposed on the exhaust system path 4.

  The turbocharger 2 is configured such that the drive turbine 22 and the compressor 21 are connected coaxially and interlocked. Then, the drive turbine 22 is rotationally driven by using the energy of the exhaust gas, and the compressor 21 is pumped by using the rotational force, whereby the intake air is pressurized and compressed, that is, supercharged and sent to the cylinder 7. .

  The EGR device 5 includes an EGR passage 51 through which exhaust gas flows and an EGR valve 52 that opens and closes the EGR passage 51. An EGR cooler 53 is disposed on the EGR passage 51.

  An electronic control unit (ECU) 6 that controls the engine 0 is a microcomputer system having a CPU 61, a memory 62, an input interface 63, an output interface 64, and the like. The input interface 63 includes a supercharging pressure signal a output from a sensor 81 that detects the pressure in the intake pipe, a rotation speed signal b output from a sensor 82 that detects the engine speed, an accelerator opening, that is, an accelerator pedal depression amount. Accelerator signal c output from sensor 83 that detects the amount of braking, brake signal d output from sensor 84 that detects the amount of depression of the brake pedal, and the position of the shift lever operated to switch the transmission gear ratio. A shift position signal e output from the sensor 85, an acceleration signal f output from a sensor 86 that detects acceleration of a vehicle or the like on which the engine 0 is mounted, and the like are input. From the output interface 64, a fuel injection signal g is output to the fuel injection valve 3, a valve opening signal h is output to the EGR valve 52, a nozzle vane operation signal i is output to the nozzle vanes of the variable capacity turbo 2.

  The CPU 61 interprets and executes a program stored in advance in the memory 62, and controls the operation of the engine 0. The CPU 61 obtains various information a, b, c, d, e, f and the like necessary for operation control of the engine 0 through the input interface 63, and based on these, the fuel injection amount, the fuel injection timing, the EGR valve 52 are acquired. The valve opening time, the nozzle vane angle, etc. are calculated, and various control signals g, h, i, etc. corresponding to the calculation results are applied via the output interface 64.

  The ECU 6 estimates the current EGR rate and intake air (fresh air) amount from the engine speed, intake pipe pressure, and EGR valve opening. Next, based on engine speed, accelerator pedal depression amount, EGR rate, intake air amount, and other environmental conditions (cooling water temperature, intake air temperature, atmospheric pressure, etc.), required fuel injection amount and fuel injection timing, The EGR valve opening that achieves the required EGR rate and the nozzle vane opening that achieves the required boost pressure are calculated. The calculation logic of these control inputs may be the same as known engine control.

  The combustion noise evaluation method of the present embodiment is intended to quantitatively evaluate the linearity of the increase in combustion noise during acceleration without changing the transmission gear ratio and the linear feeling given to the driver. For example, as shown in FIG. 2, the evaluation apparatus 1 used for carrying out the combustion noise evaluation method includes a CPU 11, a main memory 12, an auxiliary storage device 13, a display control device 14, a display 15, an operation input device 16, and a communication interface 17. Are controlled by a controller (system controller, I / O controller, etc.) 18 and operate in cooperation with each other.

  The auxiliary storage device 13 is a non-volatile memory (flash memory), a hard disk drive, an optical disk drive, or the like. The display control device 14 temporarily stores a video chip (graphics processor) that generates image data to be displayed based on a drawing instruction received from the processor 11 and sends it to the display 15, image data, and the like. The video memory etc. The operation input device 16 is a pointing device such as a push button, a keyboard, a mouse, a track pad, or a touch panel that can be operated with fingers. The communication interface 17 is a device for performing information communication with external devices, measuring instruments, and sensors. As the communication interface 17, a NIC (Network Interface Card), a wireless LAN transceiver, USB, IEEE 1394, or other serial interface or parallel interface can be adopted.

  A program to be executed by the processor 11 is stored in the auxiliary storage device 13. When the program is executed, the program is read from the auxiliary storage device 13 into the main memory 12 and decoded by the processor 11. The combustion noise evaluation apparatus 1 operates the above hardware resources according to a program, and exhibits functions as the measurement unit 101, the straight line fitting unit 102, the evaluation value output unit 103, and the determination unit 104 shown in FIG.

  The measurement unit 101 calculates the cumulative amount from the start of acceleration of the fuel consumption (fuel injection amount) at a plurality of time points in the period from the start of acceleration of the engine 0 to the end of acceleration, and the sound pressure of the combustion noise at each time point. Sampling measurement. The cumulative combustion consumption from the start of acceleration is a variable that substitutes for the engine speed and torque that increase during acceleration.

The straight line fitting unit 102 shows the relationship between the accumulated fuel consumption and the sound pressure during the period from the start of acceleration to the end of acceleration from the time series of the sampled values of the accumulated fuel consumption and the sound pressure sampled and measured by the measuring unit 101. Calculate the approximate straight line to be approximated. That is, as shown in FIG. 4, the slope and intercept of the straight line L that approximates the relationship between the cumulative combustion consumption from the start of acceleration on the horizontal axis and the combustion noise sound pressure on the vertical axis are calculated. Such straight line fitting problems are well known and are typically based on the least squares method. In the least square method, the sampling point P _i = [cumulative combustion consumption x _i , combustion noise sound pressure y _i ] (where 1 ≦ i ≦ n, n is the total number of samplings) and the approximate curve y = ax + b, The slope a and the intercept b of the approximate straight line L are determined so that the sum of squares of the residual represented by the following equation (Equation 1) is minimized.

評価値出力部１０３は、直線当てはめ部１０２で算定した近似直線の傾き、並びに、近似直線とサンプリング値との残差の分散若しくは標準偏差を出力する。残差の分散は上式（数１）の残差二乗和を（ｎ−２）で割ったものであり、標準偏差はこの分散の平方根である。（ｎ−２）で割るのは、二つの変数ｘ、ｙの回帰における残差には二つの制約条件が課されるからである。評価値出力部１０３は、算出した近似直線の傾き、並びに残差の分散若しくは標準偏差を、メインメモリ１２または補助記憶デバイス１３の所要の記憶領域に書き込む。あるいは、外部の装置に向けて送信し、ディスプレイ１５に表示し、または印刷出力する。

The evaluation value output unit 103 outputs the slope of the approximate line calculated by the line fitting unit 102 and the variance or standard deviation of the residual between the approximate line and the sampling value. The residual variance is obtained by dividing the residual sum of squares of the above equation (Equation 1) by (n−2), and the standard deviation is the square root of this variance. The reason for dividing by (n−2) is that two constraints are imposed on the residual in the regression of the two variables x and y. The evaluation value output unit 103 writes the calculated slope of the approximate straight line and the variance or standard deviation of the residual in a required storage area of the main memory 12 or the auxiliary storage device 13. Alternatively, the data is transmitted to an external device, displayed on the display 15, or printed out.

  The determination unit 104 refers to the slope of the approximate straight line and the variance or standard deviation of the residual, evaluates the combustion noise during acceleration based on these factors, and outputs the result. The slope of the approximate line represents the rate of increase in combustion noise during acceleration. The rate of increase in combustion noise may not be abrupt or too slow. Further, the variance or standard deviation of the residual represents how much the residual is scattered from the average (= 0). If the combustion noise does not rise linearly, the residual variance or standard deviation increases. Therefore, the determination unit 104 says that the slope of the approximate line is not less than a predetermined minimum value and not more than a predetermined maximum value, and the variance or standard deviation of the residual is not more than a predetermined threshold (for example, 0.412). When the condition is satisfied, a judgment is made that the increase in combustion noise is appropriate. Then, the determination result as to whether or not the increase in combustion noise is appropriate is written in a required storage area of the main memory 12 or the auxiliary storage device 13. Alternatively, the data is transmitted to an external device, displayed on the display 15, or printed out.

  According to the present embodiment, the accumulated amount from the acceleration start of the fuel consumption at a plurality of time points within the period from the acceleration start to the acceleration end of the internal combustion engine 0 and the sound pressure of the combustion noise at each time point are sampled and measured. Then, from the time series of the sampling values, an approximate line that approximates the relationship between the accumulated fuel consumption and the sound pressure in the period from the start of acceleration to the end of acceleration is calculated, the slope of the approximate line, and the approximate line The combustion noise during acceleration is evaluated on the basis of the variance of the residual between the sampling value and the standard deviation of the residual, so that the linearity of the sound pressure increase of the combustion noise during acceleration of the internal combustion engine 0 is determined. , That is, the linear feeling given to the driver can be quantitatively evaluated.

  The present invention is not limited to the embodiment described in detail above. For example, although the internal combustion engine in the above embodiment is a diesel engine, the present invention can be applied even if this is a gasoline engine (spark ignition engine).

  In addition, the combustion noise evaluation apparatus according to the present invention can be mounted on a vehicle, or the combustion noise evaluation apparatus according to the present invention can be configured using an in-vehicle ECU.

  In addition, the specific configuration of each unit, the processing procedure, and the like can be variously modified without departing from the spirit of the present invention.

  The present invention can be used for evaluation of combustion noise of an internal combustion engine mounted on a vehicle or the like.

DESCRIPTION OF SYMBOLS 1 ... Combustion noise evaluation apparatus 101 ... Measurement part 102 ... Straight line fitting part 103 ... Evaluation value output part 104 ... Judgment part

Claims (2)

A method for evaluating combustion noise during acceleration of an internal combustion engine,
Sampling and measuring the cumulative amount of fuel consumption from the start of acceleration at multiple points in the period from the start of acceleration to the end of acceleration of the internal combustion engine, and the sound pressure of combustion noise at each point in time,
From the time series of sampling values, calculate an approximate line that approximates the relationship between cumulative fuel consumption and sound pressure in the period from the start of acceleration to the end of acceleration,
A method of evaluating combustion noise during acceleration based on the slope of the approximate line and the variance of the residual between the approximate line and the sampling value or the standard deviation of the residual. Used to evaluate combustion noise during acceleration of an internal combustion engine,
A measurement unit that samples and measures a cumulative amount from the start of acceleration of fuel consumption at a plurality of time points within a period from the start of acceleration to the end of acceleration of the internal combustion engine, and a sound pressure of combustion noise at each time point;
A straight line fitting unit that calculates an approximate straight line that approximates the relationship between the accumulated fuel consumption and the sound pressure in the period from the start of acceleration to the end of acceleration from the time series of the sampling values;
A combustion noise evaluation apparatus comprising: an inclination of the approximate line, and an evaluation value output unit that outputs a residual variance or a standard deviation of the residual between the approximate line and the sampling value.

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