RU2441210C1 - Method of defining torque of caterpillar vehicle engine torque - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: two measurements of engine crankshaft angular acceleration are made with definite gear in on flat even soil surface during free acceleration with and without load and without caterpillar chains skidding. Then, engine torque is defined.

EFFECT: higher accuracy of determination in operating conditions.

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Description

The invention relates to methods for testing internal combustion engines of vehicles, in particular to methods for determining the torque of a tracked vehicle engine.

A known method of measuring engine torque of a tracked vehicle, based on measuring the torque developed by the leading sprockets on the stand for the diagnosis of skidders (Voskoboinikov I.V. Technical diagnosis of forestry machines. - M.: Lesn. Prom-st, 1987. - 192 from.).

The disadvantage of this method is the need for tests on the stand for the diagnosis of skidders.

The invention is aimed at providing the ability to determine the engine torque of a tracked vehicle directly during its operation in the field (Earth's surface).

The essence of the invention lies in the fact that on a flat horizontal section of the Earth’s surface, excluding slipping of track chains, with a particular gearbox engaged, two measurements of the angular accelerations of the crankshaft of a tracked vehicle’s engine are carried out during free acceleration without load and with load, and engine torque is defined as the ratio of the product of the mass of cargo by the square of the radius of the drive sprocket by the angular acceleration of the engine crankshaft during free acceleration without load on the angular acceleration of the engine crankshaft during free acceleration with the load to the product of the square of the gear ratio of the gearbox per square gear ratio of the main gear per square gear ratio of the planetary gear per square gear ratio of the final drive by the difference in the angular acceleration of the engine crankshaft without load and angular acceleration of the engine crankshaft during free acceleration with cargo.

The novelty lies in the fact that the torque of the tracked vehicle engine is determined by the dynamics of the angular accelerations of the crankshaft of the tracked vehicle engine when it is accelerated on a horizontal surface in a particular gear with and without load.

The drawing shows a diagram of an implementation of the proposed method for determining the engine torque of a tracked vehicle.

The internal combustion engine 1 through the clutch 2, the gearbox 3, the main gear 4, the planetary gear 5, the final drives 6 is connected to the drive sprocket 7, which engages with the track chain 8, on which the carriages 9. The upper part of the track chain is supported in a position close to horizontal, using the supporting rollers 10, and the tension of the track chain is carried out by the tensioning mechanism 11.

The proposed method for determining the engine torque of a tracked vehicle is implemented as follows.

The gear ratio of the gearbox in the corresponding gear is k _gearbox , the final drive gear ratio (GP) is k _GP , the planetary gear ratio (PM) is k _PM , the final drive gear ratio (BR) is k _BR .

The weight of the tracked vehicle with a mass of M _gm (taking into account the mass of the driver) is perceived by the rollers of the carriages 9 having a radius r _pk . The caterpillar chain is tensioned by a tensioning mechanism wheel 11 having a radius of r _kNm , the caterpillar chain is supported by supporting rollers 10 of a radius r of _etc. The length of each track chain is l _Hz , the thickness of the track chain is h _Hz , the weight of one running meter is m _Hz . The angle of wrap caterpillar chain drive sprocket _substituting α, the angle of wrap caterpillar chain wheel tensioning mechanism α _nm.

From the condition of constant kinetic energy, it follows that for a system of rotating masses consisting of an internal combustion engine, a clutch, a gearbox, a drive axle with a final drive and a differential mechanism, final drives, drive sprockets, carriage rollers, supporting rollers, chain tensioner wheels and track wheels chains, and assuming negligible effects of rolling friction, air resistance to movement, slippage between the caterpillar chains and the supporting surface:

_taken where ω, ω _{kNm, pk ω,} ω _ave - angular velocity of the drive sprocket, wheel tensioning mechanism, the roller carriage supporting the roller;

x, y - the number of carriage rollers and support rollers mounted on the tracked vehicle.

The angular velocity of wheel tensioner mechanism, a carriage roller, the backup roll associated with the angular velocity of the drive sprocket _taken ω = ω _∂v / (k _{CAT GP} k k k _{BR DIF)} through a linear velocity of the tracked vehicle V _{taken gm} = ω r and _taken, respectively, equal to:

The desired reduced moment of inertia of the system:

Obviously, the main weight contribution to J _pr (ω) is made by the mass of the tracked vehicle M _gm .

The dependence of the torque converted into traction forces of the tracks, on the engine speed:

The calculated equation of torque during acceleration of a tracked vehicle with a driver when the engine is operating according to an external characteristic (the accelerator is pressed all the way):

where ε ₁ (ω) is the angular acceleration of the engine crankshaft during acceleration of a tracked vehicle only with a driver.

The calculated equation of torque during acceleration of a tracked vehicle with a driver and a mass of M _g when the engine is running according to an external characteristic (the accelerator is pressed all the way):

where ε ₂ (ω) is the angular acceleration of the engine crankshaft during acceleration of a tracked vehicle with a driver and a cargo of mass M _gr .

Equating (5) and (6) we determine the amount:

Substituting (7) into (5), we build the characteristic of the torque creating traction on the tracks:

Substituting (7) into (6), we build the characteristic of the torque creating traction on the tracks:

Thus, knowing the gear ratios of the gearbox, final drive, planetary gear, final drive, the radius of the drive sprocket, the mass of the load and measuring the angular acceleration of the crankshaft during acceleration of a tracked vehicle without load ε ₁ (ω) and with load ε ₂ (ω ) determine the engine torque of the tracked vehicle.

The proposed method for determining the engine torque of a tracked vehicle can significantly reduce the cost of diagnostic equipment and diagnostic work while maintaining a high level of measurement accuracy.

Claims (1)

A method for determining the engine torque of a tracked vehicle, characterized in that on a flat horizontal section of the Earth’s surface, which excludes slipping of tracked chains, with a particular gearbox engaged, two measurements of the angular accelerations of the crankshaft of the tracked vehicle’s engine are carried out during free acceleration without load and with load, and engine torque is defined as the ratio of the product of the mass of the load by the square of the radius of the drive sprocket, by the angle th acceleration of the engine crankshaft during free acceleration without load, by the angular acceleration of the engine crankshaft during free acceleration with load to the product of the square of the gear ratio of the gearbox by the square of the final drive ratio, by the square of the planetary gear ratio, by the square of the final drive gear ratio , the difference between the angular acceleration of the engine crankshaft during free acceleration without load and the angular acceleration of the engine crankshaft at free acceleration with cargo.