Method and apparatus for pre-pilot fuel injection in diesel internal combustion engines
First Claim
1. In an internal combustion engine having a fuel injection cycle during a single engine cycle that includes pilot and main fuel injections, a method for reducing a heat release rate in a combustion chamber, the method comprising the steps of:
- sensing at least one engine operating parameter;
executing a pre-pilot injection algorithm;
injecting a pre-pilot fuel quantity into at least one combustion chamber at a first crank angle from top dead center and providing vaporization and homogenous mixing of the pre-pilot fuel quantity prior to said pilot injection under cylinder conditions preventing an explosive combustion of the pre-pilot fuel quantity.
16 Assignments
0 Petitions
Accused Products
Abstract
A method and apparatus for injecting fuel into a diesel engine combustion chamber is provided wherein a pre-pilot injection is injected sufficiently prior to critical mass conditions being achievable to permit vaporization and formation of a substantially homogenous mixture before a critical mass exists. Preferably, a pilot injection is injected after the pre-pilot injection but at or before a point wherein a critical mass based on the pre-pilot quantity. This will result in a reduced heat release rate will result in a slower, smoother and more controlled build up of pressure in a combustion chamber and thereby advantageously reduce combustion noise.
84 Citations
28 Claims
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1. In an internal combustion engine having a fuel injection cycle during a single engine cycle that includes pilot and main fuel injections, a method for reducing a heat release rate in a combustion chamber, the method comprising the steps of:
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sensing at least one engine operating parameter;
executing a pre-pilot injection algorithm;
injecting a pre-pilot fuel quantity into at least one combustion chamber at a first crank angle from top dead center and providing vaporization and homogenous mixing of the pre-pilot fuel quantity prior to said pilot injection under cylinder conditions preventing an explosive combustion of the pre-pilot fuel quantity. - View Dependent Claims (2)
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3. In an internal combustion engine having an injection cycle that includes both pilot and main fuel injections, a method for reducing a pressure increase rate in a combustion chamber, the method comprising the steps of:
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sensing at least one engine operating parameter;
executing a pre-pilot injection algorithm; and
injecting a pre-pilot fuel quantity into at least one combustion chamber at a first crank angle before top dead center, resulting in vaporization, substantial homogenous mixing before a critical mass is achieved and controlled burning of the pre-pilot fuel quantity as a corresponding piston travels from a compression stroke to a power stroke. - View Dependent Claims (4, 5)
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6. In an internal combustion engine having a fuel injection cycle that includes both pilot and main fuel injections, a method injecting fuel into a combustion chamber of the engine, the method comprising the steps of:
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sensing at least one pre-pilot engine operating parameter in an engine control module;
executing a pre-pilot injection algorithm;
receiving a control signal at an injector driver, from the engine control module, in accordance with the executed pre-pilot injection algorithm;
selectively operating at least one fuel injector to deliver a pre-pilot fuel injection into a corresponding combustion chamber during a compression stroke of said engine at a first crank angle before top dead center prior to said pilot injection, said injection being made under combustion chamber conditions wherein the injection of said pre-pilot fuel would not result in a critical mass capable of explosive combustion; and
mixing the pre-pilot fuel and the air in the combustion chamber to form a substantially homogenous air fuel mixture in the combustion chamber prior to critical mass conditions existing in said combustion chamber. - View Dependent Claims (7, 8, 9, 10)
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11. In an internal combustion engine having a fuel injection cycle that includes pilot and main fuel injections, a method for reducing a heat release rate in a combustion chamber comprising the steps of:
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sensing at least one pre-pilot engine operating parameter in an engine control module;
executing a pre-pilot injection algorithm;
receiving a control signal at an injector driver, from the engine control module, in accordance with the executed pre-pilot injection algorithm; and
selectively operating at least one fuel injector to deliver a pre-pilot fuel injection into a corresponding combustion chamber at a crank angle before top dead center prior to said pilot injection, said injection being made under combustion chamber conditions wherein the injection of said pre-pilot fuel would not result in a critical mass capable of explosive combustion; and
mixing the pre-pilot fuel and the air in the combustion chamber to form a substantially homogenous air fuel mixture in the combustion chamber prior to critical mass conditions existing in said combustion chamber thereby providing a controlled heat release rate. - View Dependent Claims (12, 13, 14, 15)
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16. In an internal combustion engine having a fuel injection cycle that includes a pilot injection and a main injection for injecting fuel into a combustion chamber of an engine cylinder, a method for determining a pre-pilot fuel quantity and timing for a pre-pilot injection prior to the pilot injection, the method comprising the steps of:
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sensing at least one engine operating parameter;
calculating a torque requirement from the sensed operating parameter;
calculating a total volume of fuel required to meet the torque requirement;
determining a pre-pilot fuel quantity, based upon the operating parameter, through a first look up table;
determining a pre-pilot injection timing point through a second look up table, said pre-pilot injection occurring under combustion chamber conditions wherein the injection of said pre-pilot fuel would not result in a critical mass capable of explosive combustion;
determining an injection open pulse width through the second look up table; and
determining an injection close pulse width through the second look up table;
whereby the pre-pilot injection in combination with a pilot and a main injection, results in a controlled cylinder pressure rise as a corresponding piston travels from the compression stroke to a power stroke. - View Dependent Claims (17, 18, 19, 20)
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21. In an internal combustion engine having a fuel injection cycle that includes a pilot injection and a main injection, a method for injecting fuel into a combustion chamber of the engine, the method comprising the steps of:
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sensing at least one engine operating parameter;
executing a pre-pilot injection algorithm;
selectively operating at least one fuel injector to deliver a pre-pilot fuel quantity into a corresponding combustion chamber at a first crank angle before top dead center prior to said combustion chamber having pressure and temperature conditions which would provide explosive combustion upon injection of the pre-pilot fuel quantity mass;
selectively operating at least one fuel injector to deliver a pilot fuel quantity into a corresponding combustion chamber at or before a second crank angle before top dead center subsequent to the pre-pilot injection, said second crank angle being predetermined to correspond to the existence of a critical mass based on said pre-pilot fuel quantity; and
selectively operating at least one fuel injector to deliver a main fuel quantity into a corresponding combustion chamber subsequent to the pilot injection. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28)
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Specification