Balance point diagnostics for internal combustion engine

Apparatus for measuring the balance point speed of the governor of an internal combustion engine with said governor mounted on the engine, while the engine is accelerated from a low idle speed to a high idle speed in a burst acceleration with the engine loaded only by its own inertia, drag and accessories, comprising:

• speed sensor means, including means adapted to be disposed for sensing angular rotation of the engine, for providing a speed manifestation indicative of the rotary speed of the engine;
• slope means for providing a manifestation of an empirically-determined governor cutoff slope;
• and
• processing means operative in response to said speed manifestation with said speed sensor means disposed to sense the angular rotation of said engine and to said slope means, for providing a plurality of indications of the instantaneous speed of the engine dispersed in time along the increasing portion of the power/speed characteristic of said engine as said engine accelerates from low idle to high idle, for providing manifestations of a first time interval between first and second ones of said speed measurements and of a second time interval between third and fourth ones of said speed measurements, providing manifestations of a first average speed and a first speed difference from said first two speed manifestations, and a second average speed and a second speed difference from said second two speed manifestations, and from said manifestations of speed differences, average speeds, and time increments, providing corresponding manifestations of first and second indications of power at said average speeds, providing a manifestation of the high idle speed after the engine accelerates from low idle to high idle, and providing a manifestation of said balance point speed determined as the point of intersection of a straight line representative of said empirically-determined governor cutoff slope emanating from the zero power abscissa of the power/speed characteristic of the engine at the high idle speed, and a straight line intersecting said two power measurements at the corresponding average speeds thereof.

In a method of determining the balance point speed of the governor of an internal combustion engine while mounted on the engine with the engine running, the steps of:

• providing an empirically-determined horsepower constant for an engine of the type under test;
• providing an empirically-determined governor cutoff slope for an engine of the type under test;
• accelerating the engine from a low speed to high idle speed with the engine loaded only by its own inertia, drag and accessories, and measuring speed across time increments as said engine accelerates;
• providing, from said speed and time increments and said empirically-determined horsepower constant, two indications of horsepower and corresponding speeds which define two points on the increasing portion of the horsepower/speed characteristic of the engine as it accelerates;
• measuring the high idle speed of the engine after it accelerates;
• and
• determining the balance point speed of the governor as the speed at which a first line defined by said two points on the horsepower/speed characteristic intersects with a second line emanating from the high idle speed point along the zero horsepower speed abscissa of the horsepower/speed characteristic of the engine and defined by said empirically-determined governor cutoff slope.

Apparatus for measuring the balance point speed of the governor of an internal combustion engine with said governor mounted on the engine, while the engine is accelerated from a low idle speed to a high idle speed in a burst acceleration with the engine loaded only by its own inertia, drag and accessories, comprising:

• speed sensor means, including means adapted to be disposed for sensing angular rotation of the engine, for providing a speed manifestation indicative of the rotary speed of the engine;
• first means for providing a manifestation of an empirically-determined horsepower constant;
• second means for providing a manifestation of an empirically-determined governor cutoff slope;
• and
• processing means operative in response to said speed manifestation with said speed sensor means disposed to sense the angular rotation of said engine and to said first and second means, for providing a plurality of indications of the instantaneous speed of the engine dispersed in time along the increasing portion of the horsepower/speed characteristic of said engine as said engine accelerates from low idle to high idle, for providing manifestations of a first time interval between first and second ones of said speed measurements and of a second time interval between third and fourth ones of said speed measurements, providing manifestations of a first average speed and a first speed difference from said first two speed manifestations and a second average speed and a second speed difference from said second two speed manifestations, and from said manifestations of speed differences, average speeds, time increments and said empirically-determined horsepower constant, providing corresponding manifestations of first and second indications of horsepower at said average speeds, providing a manifestation of the high idle speed after the engine accelerates from low idle to high idle, and providing a manifestation of said balance point speed determined as the point of intersection of a straight line representative of said empirically-determined governor cutoff slope emanating from the zero horsepower abscissa of the horsepower/speed characteristic of the engine at the high idle speed and a straight line intersecting said two horsepower measurements at the corresponding average speeds thereof.