CONTROL APPARATUS OF INTERNAL COMBUSTION ENGINE
First Claim
1. A control apparatus of a compression self-igniting internal combustion engine that is provided with an exhaust gas recirculation apparatus that recirculates part of exhaust gas discharged by an exhaust system in an intake system, and that performs, during a combustion process of the internal combustion engine, a main injection that is a fuel injection for torque generation from a fuel injection valve, the control apparatus comprising:
- a fuel injection control means that sets, as injection periods of the main injection;
a “
fuel injection period for initial combustion”
for initial low-temperature combustion in which fuel is sequentially burnt in a cylinder while performing an encounter rate lowering operation that lowers an encounter rate between oxygen and a fuel spray in the cylinder,a “
fuel injection period for diffusive combustion”
for performing diffusive combustion by performing, when a temperature in the cylinder is at or greater than a predetermined diffusive combustion starting temperature that leads to diffusive combustion, a fuel injection toward a region where a combustion temperature suppressing effect that is attained by exhaust gas recirculated by the exhaust gas recirculation apparatus can be used, anda “
fuel injection period for transitional combustion”
that is set between the “
fuel injection period for initial combustion” and
the “
fuel injection period for diffusive combustion”
, and that is for performing transitional combustion composed of premixed combustion that continuously connects the initial low-temperature combustion and the diffusive combustion, as fuel, which was injected when the temperature in the cylinder was lower than the diffusive combustion starting temperature after the initial low-temperature combustion had started, undergoes spray-cooling by an endothermic reaction of fuel injected in the subsequent “
fuel injection period for diffusive combustion”
.
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Accused Products
Abstract
A series of combustion forms including initial low-temperature combustion, premixed combustion, and diffusive combustion are performed when an engine operates under a low load and a medium load. The initial low-temperature combustion is carried out by performing a small-amount injection while performing an operation for lowering the encounter rate between oxygen and a fuel spray in a cylinder, and thereby the heat generation rate is kept low and the amount of NOx generated is suppressed. The premixed combustion is carried out as fuel receives heat in the initial low-temperature combustion, and the amount of smoke generated is suppressed. The diffusive combustion is accomplished as fuel travels through the combustion field of the premixed combustion, and by controlling the fuel injection timing thereof, it is possible to suitably control the timing at which the heat generation rate reaches its maximum in the aforementioned series of combustion. Thereby, it is possible to concurrently suppress the amount of NOx generated, suppress the amount of smoke generated, and secure the required torque.
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Citations
9 Claims
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1. A control apparatus of a compression self-igniting internal combustion engine that is provided with an exhaust gas recirculation apparatus that recirculates part of exhaust gas discharged by an exhaust system in an intake system, and that performs, during a combustion process of the internal combustion engine, a main injection that is a fuel injection for torque generation from a fuel injection valve, the control apparatus comprising:
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a fuel injection control means that sets, as injection periods of the main injection; a “
fuel injection period for initial combustion”
for initial low-temperature combustion in which fuel is sequentially burnt in a cylinder while performing an encounter rate lowering operation that lowers an encounter rate between oxygen and a fuel spray in the cylinder,a “
fuel injection period for diffusive combustion”
for performing diffusive combustion by performing, when a temperature in the cylinder is at or greater than a predetermined diffusive combustion starting temperature that leads to diffusive combustion, a fuel injection toward a region where a combustion temperature suppressing effect that is attained by exhaust gas recirculated by the exhaust gas recirculation apparatus can be used, anda “
fuel injection period for transitional combustion”
that is set between the “
fuel injection period for initial combustion” and
the “
fuel injection period for diffusive combustion”
, and that is for performing transitional combustion composed of premixed combustion that continuously connects the initial low-temperature combustion and the diffusive combustion, as fuel, which was injected when the temperature in the cylinder was lower than the diffusive combustion starting temperature after the initial low-temperature combustion had started, undergoes spray-cooling by an endothermic reaction of fuel injected in the subsequent “
fuel injection period for diffusive combustion”
. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification