Engine brake horsepower test without external load

• US 3,964,301 A
• Filed: 10/21/1974
• Issued: 06/22/1976
• Est. Priority Date: 10/21/1974
• Status: Expired due to Term

• Current Assignee: RCA Corporation (General Electric Company)
• Original Assignee: RCA Corporation (General Electric Company)
• Inventors: Nolan, Thomas Edward Jr., Hanson, Richard Eric
• Primary Examiner(s): Ruehl, Charles A.
• Application Number:
  US05/516,503
• Time in Patent Office: 610 Days
• Field of Search: 73/116, 73/117.2, 73/117.3
• US Class Current: 73/114.14
• CPC Class Codes: F02D 2200/1006 Engine torque losses, e.g. friction or pumping losses or losses caused by external loads of accessories
• CPC Class Codes: G01L 3/242 by measuring and simultaneously multiplying torque and velocity
• CPC Class Codes: G01M 15/044 by monitoring power, e.g. by operating the engine with one of the ignitions interrupted; by using acceleration tests

Abstract

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.

Claims

1. Apparatus for testing an internal combustion engine, comprising

means to operate the engine at an equilibrium speed determined by friction torque with all but one of n ignitions inhibited,

means to decelerate the engine without any ignition, and

means to measure the average rate of deceleration of the engine during a predetermined deceleration speed range including the equilibrium speed,

whereby the brake torque of the engine is obtained by multiplying the average rate of deceleration by the known inertia of the engine and by n - 1.

2. Apparatus according to claim 1, and in addition, means to multiply the average rate of deceleration by the known inertia of the engine and by n - 1 to obtain the brake torque of the engine at the equilibrium speed.

3. Apparatus according to claim 2, and in addition, means to compare said determined brake torque with a known standard brake torque test limit and provide a "passed" or "failed" display.

4. Apparatus according to claim 1, and in addition, means operative following operation of said engine at the equilibrium speed to accelerate the engine with full ignition to a speed above the equilibrium speed.

5. Apparatus for determining the brake torque of an internal combustion engine without connecting an external load to the engine, comprising

means to operate the engine with all but one 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 within the useful speed range of the engine,

means to determine the average rate at which the engine decelerates during a predetermined deceleration speed range including said equilibrium speed when operating with all ignitions inhibited, and

means to multiply the average rate of deceleration by the known inertia of the engine to determine the friction torque at the equilibrium speed,

whereby the brake torque of the engine at the equilibrium speed can be determined by multiplying the friction torque by n - 1, and the brake horsepower at the equilibrium speed can be determined by multiplying the brake torque in foot pounds by the equilibrium speed in radians per second, and dividing by 550.

6. Apparatus as defined in claim 5, wherein said means to determine the average rate at which the engine decelerates includes means to operate the engine with full ignition to accelerate the engine above the equilibrium speed, and means subsequently to operate the engine without ignition so that the engine decelerates through the equilibrium speed.

7. Apparatus as defined in claim 5, wherein said means to determine the average rate at which the engine decelerates includes means to operate the engine without ignition so that the engine decelerates from the equilibrium speed.

8. The method of testing an internal combustion engine, comprising

operating the engine at an equilibrium speed determined by friction torque with all but one of n ignitions inhibited,

decelerating the engine without any ignition, and

measuring the average rate of deceleration of the engine during a predetermined deceleration speed range including the equilibrium speed,

whereby the brake torque of the engine is obtained by multiplying the average rate of deceleration by the known inertia of the engine and by n - 1.

9. The method according to claim 8 and in addition the step of multiplying the average rate of deceleration by the known inertia of the engine and by n - 1.

10. The method of determining the brake torque of an internal combustion engine without connecting an external load to the engine, comprising the steps of

operating the engine with all but one 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 within the useful speed range of the engine,

measuring the average rate at which the engine decelerates during a predetermined deceleration speed range including said equilibrium speed when operating with all ignitions inhibited, and

forming the product of the average rate of deceleration and the known inertia of the engine to determine the friction torque at the equilibrium speed,

whereby the brake torque of the engine at the equilibrium speed can be determined by multiplying the friction torque by n - 1, and the brake horsepower at the equilibrium speed can be determined by multiplying the brake torque in foot pounds by the equilibrium speed in radians per second, and dividing by 550.