SU767603A1 - Device for measuring specific fuel cinsumption of internal combustion engine - Google Patents

Description

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The invention relates to devices for bench testing of an internal combustion engine (ICE), namely, devices for measuring the specific fuel flow ratio. 5

The specific fuel consumption meters of internal combustion engines are known, comprising a rotational speed sensor with a frequency output, a torque with a pulse output of 10 and a metering of fuel consumption time included at the inputs of the converter circuit Ti,

However, the known device has insufficient accuracy in measuring the specific fuel consumption due to the fact that the measurement of the torque on the shaft and the rotational frequency to calculate the specific consumption of fuel)) is charged once during the fuel consumption time of up to -20 is for average diesel engines from 50 to 2000 s.

Due to the instability of the internal combustion engine, the torque values on the shaft and the shaft speeds vary due to various known factors. And since in the known device the values of the torque on the shaft and the DL

shaft rotational speeds are measured once during the fuel dose expenditure, they are random and do not carry information about their average value over the entire fuel consumption expenditure period, which determines the low accuracy of the specific flow measurement.

The use of automatic control to stabilize the shaft rotational speed or torque on the shaft in the process of measuring the specific fuel consumption when using a known device does not lead to a substantial increase in measurement accuracy, since stabilizing one parameter eliminates the possibility of adjusting the other, which 1st can be arbitrarily changed relative to first in a range. In addition, the incorporation of an automatic control system significantly complicates a known device.

The purpose of the present invention is to improve the accuracy of measurement of specific fuel consumption while simplifying the device.

This goal is achieved by the fact that the conversion meter is designed as an integrating multiplier, a dividing device and a large-scale fuel dose setting unit; moreover, the inputs of the integrating multiplication device serve as inputs of the educational circuit, and the inputs of the multiplying device and large-scale setting device are connected to the inputs of the division device fuel dose.

The multiplying integrator contains a three-input circuit AND, the first and second triggers, a pulse counter and a delay element, the outputs of the first and second triggers are connected to the first and second inputs AND, the output of the AND circuit is connected to the counting input of the pulse counter, connected to the input of the second trigger, the inputs of the first and second trigger and the third input of the AND circuit serve as inputs of the integrating multiplication device, and the output of the pulse counter serves as its output .:

In bench tests of an internal combustion engine to obtain complete information about its technical condition in a known device at the same time as the specific one. fuel consumption is determined by the frequency of shaft rotational speed, torque and shaft power.

These functions can be implemented in the present invention by introducing additional secondary converters into it that convert the signals of the rotation sensor and the torque sensor into a form suitable for display or input to an external device, such as a computer, to provide data to. ACS.

FIG. 1 shows a diagram of the specific fuel consumption meter; Fig. 2 is a time diagram of the operation, explaining the principle of the meter,.

The meter contains a shaft rotational speed sensor 1 with a frequency output, a torque sensor 2 on the shaft with a pulse output, a meter 3 of fuel consumption time, an integrating multiplication device 4, a dividing device 5 and a large-scale setting unit for 6 fuel doses. - The multiplier integrator 4 comprises the first trigger 7, the second trigger 8, the three-input circuit 9, the pulse counter 10 and the support element 11.

To the inputs of the trigger 7 are connected the torque sensor echhrs 2.

The trigger input 7 is connected to the meter 3 time consumption of a dose of fuel. Circuit 9 is connected by its inputs to the outputs of trigger 7, trigger 8

and shaft speed sensor 1, and you’ll have one, counter 10, Meter 3 of fuel consumption time contains a weighing device 12 with sensor 13 of the beginning of the consumption time and sensor 14 of the end of time, fuel dose consumption, valve control device 15 -18 and measuring bacho 19.

The operation of the meter is illustrated by the timing diagram (Fig. 2).

Pulses are taken from the output of the rotational speed sensor 1 at a frequency that is proportional to the frequency of rotation of the shaft (Fig. 2a).

At the first output of the torque sensor 2, a pulse is formed on the shaft (Fig. 2b) corresponding to the reference point of the dynamometer needle readings, at the second output a pulse of the end point of the readout of the dynamometer needle (Fig. 2c) is formed. These signals are sent to a trigger 7, at the output of which a pulse is formed, the duration of which is proportional to the torque on the shaft (Fig. 2d). At the outputs of the sensors 13 and 14, the beginning and end of the time of the fuel dose consumption, a pool of the beginning and end of the expenditure is formed accordingly; doses (Fig. 2d, f), which are triggered by trigger 8 and the duration of the flow is proportional to the time of the fuel dose consumption (Fig. 2g);

Pulses from triggers 7 and 8 and rotational speed sensor 1 are fed to circuit 9, at the output of which a sequence of pulses is formed (Fig. 2h), the number N of which during a single cycle of consumption of fuel dose is proportional to the product

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N .n.T.

n is the frequency of rotation of the shaft,

where is the torque; Tc | time spent on fuel consumption. These pulses go to the meter.

and by a command received by the dividing device 5 from the sensor 14 at the end of the fuel dose consumption, and the result from the counter 10 is copied to the dividing device 5, which performs an okra: a unit for calculating the specific

- - at

fuel consumption Q -) /,

6)

where P is the weight of the dose of fuel

. the scale factor needed to display the result on a digital scoreboard in units of units (g / hp). The result of the calculations is stored in a device for dividing it until it is replaced with the next value obtained as a result of a subsequent measurement.

The product K, P in expression (2) is a constant value and is realized by a digital scale unit 6 for the dose of fuel. The impulse from the sensor 14 of the end of the dose countdown, through the delay time of the element 11, necessary for transferring information from the counter 10 to the dividing device 5, resets the counter 10 to the zero state, thus preparing the circuit for the next flow measurement cycle. The pulse from sensor 14 also enters the valve control device 15, which generates signals for opening valve 16, through which a fraction of the fuel enters measuring tank 19, closing valve 17 of dose rate and opening valve 18 for direct fuel supply to the engine from the fuel line. As the fuel is refilled, the arrow of the measuring device .12 returns to the beginning of the scale until the pack triggers the sensor 13, which through the valve control device 15 through the delay time necessary for the arrow to pass through some initial displacement is closed. The valve 16 adds fuel to the tank 19, opens the valve 17 for supplying a dose of fuel to the engine and closes the valve 18 for directing fuel to the engine from the line. At the same time, fuel consumption from tank 19 begins, which is accompanied by turning the arrow of the weighing device 12 in the opposite direction, which is caused by a decrease in fuel in tank 19. When the arrow passes under the sensor 13, the dose expenditure starts measuring the time dose, trigger trigger 8 is controlled. The described measurement process is specific. fuel consumption. repeat. The device according to the present invention provides a predetermined measurement accuracy of the specific fuel consumption g, /, under the conditions 2f ″, T ;, where Kj is a ratio equal to the ratio of the length of the dynamometer scale to the circumference length of the radius of the scale, the arrow of which is associated with the sensor torque is torque, f is the frequency of the pulse of the rotational speed sensor, - the meter error is maximally reduced. . The solution of inequalities (3) and (k) leads to the relation:. Tn - (5) where Tfi is the repetition period of the rotational speed sensor impulse} T is the repetition period of the torque sensor impulses.

767603 An analysis of the testing processes of medium power diesel engines of various types showed that this condition is always fulfilled. For example, when testing the D54M engine, the frequency of the pulses taken from the rotational speed sensor is 1800 Hz, the rotational speed of the engine of the torque sensor is 25 Hz, the expenditure time of the test fuel dose is 90 s. At the same time, the maximum reduced error of the measuring circuit is 0.2%, which is significantly higher than the measurement accuracy by known devices. The economic effect of introducing a meter is to improve the accuracy of measuring specific fuel consumption. This will lead to a reduction in the output of engines that do not meet the technical requirements for specific fuel consumption, and the latter - to a certain economy of fuel by engines during operation .-. In addition, the use of this device eliminates the system of automatic control of rotational speed or torque, which gives the economic effect of simplifying the instrumentation base of the test station. Formula 1. The specific fuel consumption meter of the internal combustion engine containing a frequency sensor with a frequency output, a sensor torque with time pulse output and fuel consumption time meter, including inputs: converter circuit, distinguishing In order to increase accuracy, the converter circuit is designed as an integrating multiplier, a dividing device and a fuel dose scaler, while the inputs of the multiplication integrator serve as inputs to the conversion circuit and the outputs of the multiplying device are connected to the inputs of the multiplier. scale unit of the dose of fuel. 2. The meter according to claim 1, characterized in that the integrating multiplication device contains a three-input circuit AND, the first and second triggers, a pulse counter and a delay element, and the outputs of the first and second triggers are connected to the first and second inputs, to the counting input of the counter the pulses are connected to the output of the AND circuit, and to the installation one — a delay element connected to the input of the second trigger, the inputs of the first and second triggers, and the third input of the circuit serve as inputs of the multiplying integrator, and the output of the pulse counter serves as output.

Sources of information taken into account in the examination

1. US patent 3802256, class 73-113, published. 1970.

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Claims (2)

Claim 1. The specific fuel consumption meter * of the internal combustion engine fuel, comprising a rotational speed sensor with a frequency output, a torque sensor with a time-pulse output and a time meter for fuel dose consumption, including on the inputs of a converter circuit, characterized in that, with In order to increase accuracy, the conversion circuit is made in the form of an integrating multiplication device, a division device and a large-scale fuel dose adjuster, and the inputs of the integrating multiplication device serve as inputs to the one time! circuit, and the outputs of the integrating multiplication device and are connected to the inputs of the division device. large-scale fuel dose adjuster; 2. The meter pop. 1, characterized in that the integrating multiplication device contains a three-input circuit And, the first and second triggers, a pulse counter and a delay element, moreover, the outputs of the first and second triggers are connected to the first and second inputs AND to the counting input of the pulse counter the output of circuit And is connected, and to the installation one there is a delay element associated with the input of the second trigger, the inputs of the first and second triggers and type 60 are the input of the circuit and serve as inputs of the integrating multiplication device, and the output of the pulse counter serves as its output.