RU2361187C1 - Method of determining internal combustion engine power - Google Patents

Abstract

FIELD: physics; measurement.

SUBSTANCE: invention pertains to the technology of testing internal combustion engines mainly in operating conditions. The objective is achieved due to that, fuel input is instantly increased to the maximum under operating conditions of the internal combustion engine at minimum idling speed, and once nominal speed is attained, acceleration of the crankshaft is measured. The same operations are then repeated, but with a flywheel with known moment of inertia, connected to a power shaft, which allows for determining the real moment of inertia of the engine, so that from the product of acceleration and the real moment of inertia, torque can be determined and consequently, power.

EFFECT: more accurate measurement of power of an internal combustion engine.

Description

The invention relates to techniques for testing internal combustion engines mainly in operating conditions.

A known method for determining the power of an internal combustion engine, in which the fuel supply is turned off when the engine is running at maximum idle speed, and in the process of coasting, the values of the parameters determining the indicator acceleration / 1 / are measured.

The disadvantage of this method is the inconvenience associated with turning off the fuel supply during engine operation, the low accuracy of the measurement as a result of the oscillation of the rail of the fuel pump under the action of inertia and compression force of the regulator spring.

Closest to the technical nature of the present invention is a method for determining the effective power of an internal combustion engine / 2 /. The essence of this method is as follows: under operating conditions at minimum engine idle speed, the fuel supply is instantly increased to a maximum value and, upon reaching the nominal speed, the acceleration of the crankshaft is measured so that the torque is judged by the product of the acceleration by the reduced moment of inertia of the engine and accordingly about power.

The disadvantage of this method is the low accuracy of power measurement, due to the adoption of the moment of inertia as a constant value for engines of the same brand.

The objective of the present invention is to improve the accuracy of measuring the power of an internal combustion engine.

The task is achieved by the fact that in the conditions of operation of the internal combustion engine at minimum engine idle speed, the fuel supply is instantly increased to the maximum value and, upon reaching the nominal speed, the acceleration of the crankshaft is measured, then the same operations are repeated, but with the flywheel of known moment of inertia attached to the power take-off shaft, which will determine the actual moment of inertia of the engine according to the formula

in order to judge the torque and, accordingly, power by the product of acceleration at the actual moment of inertia.

The proposed method is as follows. The internal combustion engine is heated to the normal operating temperature of the coolant and oil, then the fuel control lever is set to the position corresponding to the minimum idle speed, the fuel supply is instantly increased to the maximum value. Using a special device, measure the acceleration of the crankshaft during acceleration of the engine when it reaches its rated speed. A flywheel of a known moment of inertia is connected to the power take-off shaft and, at the moment it reaches the nominal speed of the crankshaft, acceleration is measured. Acceleration measurement is carried out by a device of the IMD type.

The actual moment of inertia of the engine is determined by the formula

where I _D is the actual moment of inertia of the engine, kgm ² ,

- приведенный момент инерции маховика, кгм²,

- reduced moment of inertia of the flywheel, kgm ² ,

ε ₁ , ε ₂ - respectively, the angular acceleration of the crankshaft in nominal mode during acceleration without a flywheel and with a flywheel, s ^-2 .

Accordingly, the power is determined by the formula

- угловое ускорение коленчатого вала, с^-2;Where

- angular acceleration of the crankshaft, s ^-2 ;

ω _nom - nominal angular velocity of the engine crankshaft, rad · s ^-1 .

Information sources

1. AS of the USSR 877369, BI No. 40, 1981

2. AS of the USSR 243999, BI No. 17, 1969 - prototype.

Claims (1)

A method for determining the power of an internal combustion engine, which consists in the fact that under operating conditions at minimum engine idle speed, the fuel supply is instantly increased to a maximum value and, upon reaching the nominal speed, the crankshaft acceleration is measured, characterized in that the same operations are repeated, but with the flywheel of the known moment of inertia attached to the power take-off shaft, and the actual moment of inertia of the engine is determined by the formula

where I _D is the actual moment of inertia of the engine, kgm ² ;

- reduced moment of inertia of the flywheel, kgm ² ;
ε ₁ , ε ₂ - respectively, the angular acceleration of the crankshaft in nominal mode during acceleration without a flywheel and with a flywheel, s ^-2 ,
so that by the product of the values of the acceleration of the crankshaft by the actual moment of inertia of the engine to judge the torque and, accordingly, the power.