Method and apparatus for electrically driving engine valves
AssigneeGeneral Motors Corporation
InventorsThaddeus Schroeder, Rassem R. Henry, Bruno P. B. Lequesne, Balarama V. Murty
Life of this patent
Estimating the term…
Abstract
A motor control includes position transducers for generating crankshaft position and motor position pulse trains. The pulse trains are compared to detect any phase difference between engine and motor. Tables are generated to define the desired phase difference needed for particular valve characteristics. The phase difference represents the instantaneous deviation from the basic profile. One of the tables is selected according to the engine conditions and the motor is driven to achieve the desired phase differences.
Claims7
A drive for engine valve control comprising:
- an engine valve;
- a rotary electric motor normally operable in continuous rotary motion and coupled to the valve for opening and closing the valve upon motor rotation;
- and
- a motor control including an engine crankshaft position transducer for producing an engine crankshaft position signal, a motor position transducer for producing a motor position signal, and a controller responsive to the position signals for controlling the motor and thus the valve position in accordance with engine crankshaft position, wherein the motor control further includes:
- an engine control module for defining the required phase relationship of motor position and engine crankshaft position to realize the desired valve operation;
- means for comparing the position signals for a plurality of consecutive engine crankshaft positions to determine the phase difference between the engine crankshaft and motor positions;
- and
- a drive responsive to the phase difference and the required phase relationship for generating motor current to control the motor to the required phase relationship.
A method of controlling rotary electric motors which control engine valves such that each valve opens and closes for every control cycle of its respective motor, the method comprising the steps of:
- generating a train of engine crankshaft position signal pulses;
- generating a train of motor position signal pulses for each motor having a number of pulses in each valve cycle equal to the number of engine crankshaft position pulses in two engine crankshaft revolutions;
- continually comparing the trains of pulses to determine the actual phase of each motor relative to engine crankshaft position;
- establishing a desired valve opening profile by defining the desired phase of each motor for each engine crankshaft position signal pulse;
- and
- driving each motor to control the actual motor phase to the desired phase.
Dependencies are inferred from the claim text.