摘要:
Methods and systems are provided for reducing idling torque imbalances between cylinders by actuating a common camshaft to which the cylinders are coupled. The camshaft may be adjusted within camshaft limits during each combustion event of each cylinder. In this way, idling NVH issues may be addressed.
摘要:
Methods and systems are provided for identifying and differentiating knock and pre-ignition using a plurality of knock sensors distributed along an engine block. By dynamically adjusting cylinder-specific assignment of the knock sensors for knock detection and pre-ignition detection based on operating conditions of each cylinder, knock and pre-ignition is more reliably identified and distinguished.
摘要:
Methods and systems are provided for mitigating engine pre-ignition based on a feed-forward likelihood of pre-ignition and feedback from a pre-ignition event. In response to an indication of pre-ignition, a cylinder may be enriched while an engine load is limited. The enrichment may be followed by an enleanment to restore exhaust catalyst feed-gas oxygen levels. The mitigating steps may be adjusted based on engine operating conditions, a pre-ignition count, as well as the nature of the pre-ignition.
摘要:
Methods and systems are provided for addressing cylinder pre-ignition by adjusting a spray angle of fuel injected into a cylinder responsive to an indication of pre-ignition. A spray pattern of fuel injected in the cylinder is varied based on a cylinder pre-ignition count to reduce cylinder wall impingement of injected fuel while improving air-fuel mixing in the cylinder.
摘要:
Methods and systems are provided for mitigating engine pre-ignition based on a feed-forward likelihood of pre-ignition and feedback from a pre-ignition event. In response to an indication of pre-ignition, a cylinder may be enriched while an engine load is limited. The enrichment may be followed by an enleanment to restore exhaust catalyst feed-gas oxygen levels. The mitigating steps may be adjusted based on engine operating conditions, a pre-ignition count, as well as the nature of the pre-ignition.
摘要:
Methods and systems are provided for identifying and differentiating knock and pre-ignition using a plurality of knock sensors distributed along an engine block. By dynamically adjusting cylinder-specific assignment of the knock sensors for knock detection and pre-ignition detection based on operating conditions of each cylinder, knock and pre-ignition is more reliably identified and distinguished.
摘要:
A system and method for operating an engine having ionization signal sensing include detecting plug fouling and controlling the engine using progressively more aggressive control strategies if the fouling condition persists. A first control strategy may be used when the number of engine starts or running time are below corresponding thresholds and a second strategy otherwise. The first strategy may employ progressively more aggressive control procedures to eliminate spark plug deposits that may include repetitive sparking, exhaust cycle sparking, increasing engine loading, advancing spark timing, increasing air/fuel ratio, and increasing idle speed, for example. The second strategy may include similar corrective actions employed in a different order and/or to a lesser degree in an attempt to eliminate plug fouling without any noticeable change in engine operation or performance as perceived by the vehicle operator. The control strategies may be applied to individual cylinders, cylinder banks, or all cylinders.
摘要:
In one example, a method of operating an engine in a vehicle is described. The method comprises delivering a first substance to a cylinder of the engine from a first injector; delivering a second substance to the cylinder of the engine from a second injector, where the second substance has a greater heat of vaporization than the first substance; and increasing injection of the second substance responsive to an exhaust over-temperature condition.
摘要:
A system and method for operating a multiple cylinder internal combustion engine having at least one actuator for controlling charge dilution of at least one cylinder and at least one spark plug per cylinder include attempting to improve combustion quality by modifying ignition energy of the at least one spark plug before modifying charge dilution of the cylinder, and modifying both ignition energy and charge dilution substantially simultaneously to establish combustion if an ionization sense signal associated with the cylinder indicates a misfire.
摘要:
A system and method for operating a multiple cylinder internal combustion engine having at least two spark plugs per cylinder include selectively isolating all but one spark plug associated with the cylinder at least during an ionization current sensing period to reduce or eliminate interference among ionization current signals flowing through more than one spark plug.