Rca Inc.

US Government as Represented by the Secretary of the Army

Richard Eric Hanson

Thomas Edward Nolan, Jr

William Fulmer Fordyce

Ronald Elmer Tetrev

Howard E Fineman

Steven M Schlosser

Lawrence M Hill

The compression in the cylinders of an internal combustion engine is tested by analyzing the battery voltage waveform when the engine is cranked by the starter motor with ignition or fuel inhibited. The detected voltage waveform is amplified in a manner to emphasize the a-c component having cycles between positive voltage peaks, each cycle having a negative voltage peak due to a compression stroke. A missing negative voltage peak indicates a very low compression in one cylinder. The voltage cycles are integrated and the integrals are compared to detect compression imbalance. The base level of each integration is made equal to the level of an adjacent positive voltage peak.

Compression test using battery voltage waveform during cranking

A method for determining the rotational moment of inertia of an engine, crising the steps of carrying out engine deceleration tests, first with the engine unloaded and later with the engine sufficiently loaded to provide a recordable difference in deceleration rate (or elapsed time). Moment of inertia is determined as the numerical value of the added load divided by the difference in deceleration rates, before and after the load is applied.

Method for determining engine moment of inertia

The full-power condition of an internal combustion diesel engine is tested by an acceleration burst test in which the engine initially operated at idle speed is suddenly given full throttle and caused to accelerate to a maximum governed speed. A tachometer means coupled to the engine produces one electrical pulse per engine cycle. The time taken in going between a predetermined low speed and a predetermined high speed is accurately determined, despite irregularities in the engine, by adding a portion determined by interpolation in the time period between pulses at the low speed, and a portion determined by interpolation in the time period between pulses at the high speed, to the intermediate time periods.

Acceleration burst test apparatus and method for internal combustion

An apparatus for, and method of, detecting the uneven operation of the individual cylinders in an internal combustion engine, and for diagnosing the cause thereof. The engine is operated at any convenient idle speed. Power cycle time periods between successive ignition times are measured, the deceleration rates between successive time periods are then computed, and finally the average deceleration rates for the respective cylinders are computed. Misfires occurring randomly in cylinders are detected when individual deceleration rates exceed the average deceleration rate for the corresponding cylinder by a predetermined limit amount. Repeated malfunctioning in an individual cylinder is detected when the average deceleration rate for the weakest cylinder exceeds that for the strongest cylinder by a predetermined limit amount.

Detecting malfunction in cylinders of internal combustion engines

Apparatus for and method of measuring the ignition timing of an internal combustion engine while cranking the engine with the starter motor, and with the ignition inhibited. Starter motor current fluctuations are examined to determine the times of current peaks due to compression in individual cylinders. Means coupled to the ignition circuit determines the times of points openings. A time difference signal representing the lead or lag of the ignition relative to the starter current peaks is generated. The lead or lag is then related to the time of top dead center in terms of degrees.

Measuring ignition timing using starter current

Apparatus for and method of determining the brake torque and horsepower of an internal combustion engine without connecting an external load. Means are provided to operate the engine at full throttle and with all but one out of n of successive ignitions inhibited, the value n being selected so that the engine operates with just enough power to equal the frictional load of the engine and maintain an equilibrium speed at the upper end of the engine speed range. The engine is then operated momentarily with full ignition, and then with no ignition, during which a determination is made of the rate at which the engine decelerates through the equilibrium speed. The deceleration rate is multiplied by the known inertia of the engine to determine the friction torque of the engine at the equilibrium speed. The friction torque is multiplied by n - 1 to predict the brake torque of the engine at the equilibrium speed when operated normally with external load. Horsepower is determined by multiplying torque and speed.

Engine brake horsepower test without external load

Satisfactory or unsatisfactory engine compression is diagnosed by comparing the amplitude of the starter motor current, when cranking an engine having its ignition inhibited, with a reference value. The reference value is adjusted in accordance with the intake manifold absolute pressure, as determined from measurements during the test of ambient pressure and intake manifold vacuum.

Determining engine compression from starter motor current

Means for and method of testing the power of an internal combustion engine. A tachometer means coupled to the engine generates one electrical pulse per engine cycle of the engine. While the engine is full-throttle accelerated, a computer means measures the time periods between successive pulses, each time period constituting the reciprocal of the average engine speed during the particular engine cycle. One-half of the time period corresponding with a low speed and one-half of the time period corresponding with a high speed are added to the intermediate time periods to determine an acceleration time period which is a measure of engine power. The acceleration rate is determined by subtracting the reciprocal of the time period corresponding with the low speed from the reciprocal of the time period corresponding with the high speed to determine the speed change, and dividing the speed change by the acceleration time period. Brake torque is determined by multiplying the acceleration rate by the known inertia of the engine. The engine is then shut off and the deceleration rate is determined and is multiplied by the known inertia of the engine to determine the friction torque of the engine. The brake torque is added to the friction torque to determine the indicated (total) torque of the engine.

Power test means and method for internal combustion engines

A method of testing compression capabilities of multi-cylinder engines wh are cranked with electrically-energized starter motors. The cylinders are prevented from firing, and the engine is cranked by the starter motor. During the cranking period measurements are taken of the starter motor current. A comparison of the peak current and average current provides an indication of the compression capability of the engine.

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Winchester, MA, United States of America

Richard Eric Hanson