Internal-combustion engines – Combustion chamber means having fuel injection only – Using multiple injectors or injections
Reexamination Certificate
2000-07-31
2001-10-23
Mohanty, Bibhu (Department: 3741)
Internal-combustion engines
Combustion chamber means having fuel injection only
Using multiple injectors or injections
C123S300000
Reexamination Certificate
active
06305348
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a method for controlling a compression-ignition internal combustion engine.
BACKGROUND ART
In the control of fuel injection systems, the conventional practice utilizes electronic control units having volatile and non-volatile memory, input and output driver circuitry, and a processor capable of executing a stored instruction set, to control the various functions of the engine and its associated systems. A particular electronic control unit communicates with numerous sensors, actuators, and other electronic control units necessary to control various functions, which may include various aspects of fuel delivery, transmission control, or many others.
Fuel injectors utilizing electronic control valves for controlling fuel injection have become widespread. This is due to the precise control over the injection event provided by electronic control valves. In operation, the electronic control unit determines an energizing or excitation time for the control valve corresponding to current engine conditions. The excitation of the control valve causes a cascade of hydraulic events leading to the lifting of the spray tip needle, which causes fuel injection to occur.
Several attempts have been made to enhance fuel injection capabilities. One such method is known as split injection. Split injection consists of a first injection, called the pilot injection, followed by a delay, and then a second injection, referred to as the main injection. When performing split injection, precise control over pulse quantities, timing, and separation is essential. Many times, operating conditions at which split injection may be performed are restricted to lower engine speeds due to difficulties in achieving precise control over the injection process.
DISCLOSURE OF INVENTION
It is therefore an object of the present invention to provide a method for enhanced split injection that enhances cold temperature engine operation.
In carrying out the above object and other objects and features of the present invention, a method of controlling fuel delivery in an internal combustion engine is provided. The engine is operable in a plurality of operating modes including a start mode and a normal mode. The normal mode includes an idle normal mode and a non-idle normal mode. The engine has a split injection status, which may be set as enabled or disabled. The engine has a fuel injection system configured to perform a split injection wherein a pilot injection event is separated from a main injection event by a delay when the split injection status is enabled. The fuel injection system is configured to perform a single injection when the split injection status is disabled. The method comprises establishing a temperature threshold, monitoring an engine operating temperature, and comparing the engine operating temperature to the temperature threshold. The method further comprises operating the engine in the start mode, and enabling the split injection status without subjection to the temperature comparison while the engine operates in the start mode. The method further comprises, after operating the engine in the start mode, operating the engine in the idle normal mode, and enabling the split injection status without subjection to a time limit while the engine operates in the idle normal mode and the engine operating temperature falls below the temperature threshold to enhance cold temperature engine operation. Otherwise, the split injection status is disabled while the engine operates in the idle normal mode.
In one embodiment, the method further comprises operating the engine in the non-idle normal mode, and disabling the split injection status while the engine operates in the non-idle normal mode. Alternatively, the method further comprises operating the engine in the non-idle normal mode, and enabling the split injection status without subjection to a time limit while the engine operates in the non-idle normal mode and the engine operating temperature falls below the temperature threshold to enhance cold temperature engine operation. Otherwise, the split injection status is disabled while the engine operates in the non-idle normal mode.
Further, in carrying out the invention, an engine controller is provided. The engine controller includes a computer readable storage medium having instructions thereon that are executable by the engine controller to perform a method of controlling fuel delivery in an internal combustion engine. The medium further comprises instructions for establishing a temperature threshold, instructions for monitoring an engine operating temperature, instructions for comparing the engine operating temperature to the temperature threshold, and instructions for operating the engine in the start mode. The medium further comprises instructions for enabling the split injection status without subjection to the temperature comparison while the engine operates in the start mode. Further, the medium comprises instruction for after operating the engine in the start mode, operating the engine in the idle normal mode. Further, the medium comprises instructions for enabling the split injection status without subjection to a time limit while the engine operates in the idle normal mode and the engine operating temperature falls below the temperature threshold to enhance cold temperature engine operation. Otherwise, the split injection status is disabled while the engine operates in the idle normal mode.
In some embodiments, the medium further comprises instructions for operating the engine in the non-idle normal mode. In the non-idle normal mode, the split injection status may be disabled, or enabled. When the split injection status is enabled, the status is enabled without subjection to a time limit while the engine operates in the non-idle normal mode and the engine operating temperature falls below the temperature threshold to enhance cold temperature engine operation.
Still further, in carrying out the present invention, an internal combustion engine is provided. The internal combustion engine comprises an engine block with a plurality of cylinders, a plurality of fuel injectors disposed at the cylinders, and an engine controller including a computer readable storage medium having instructions thereon that are executable by the engine controller to perform a method of controlling fuel delivery in the internal combustion engine. The medium has instructions for establishing a temperature threshold, instructions for monitoring an engine operating temperature, instructions for comparing the engine operating temperature to the temperature threshold, and instructions for operating the engine in the start mode. The medium further has instructions for enabling the split injection status without subjection to the temperature comparison while the engine operates in the start mode. The medium further has instructions for after operating the engine in the start mode, operating the engine in idle normal mode. The medium further has instructions for enabling the split injection status without subjection to a time limit while the engine operates in the idle normal mode and the engine operating temperature falls below the temperature threshold to enhance cold temperature engine operation. Otherwise, the split injection status is disabled while the engine operates in the idle normal mode.
Further, in some embodiments, the medium further has instructions for operating the engine in the non-idle normal mode. In the non-idle normal mode, the split injection status may be disabled, or enabled without subjection to a time limit while the engine operates in the non-idle normal mode and the engine operating temperature falls below the temperature threshold to enhance cold temperature engine operation.
The advantages accruing to the present invention are numerous. For example, methods of the present invention provide delivery of single or multiple fuel injection pulses per cylinder firing with precision of pulse quantities, separation, and timing adequate for enhancing cold temperature engine
Avery, Jr. Richard M.
Grosmougin Anne-Lise
Brooks & Kushman P.C.
Detroit Diesel Corporation
Mohanty Bibhu
LandOfFree
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