Internal-combustion engines – Combustion chamber means having fuel injection only – Combustible mixture stratification means
Patent
1998-04-28
1999-11-23
Kwon, John
Internal-combustion engines
Combustion chamber means having fuel injection only
Combustible mixture stratification means
123430, F02B 1700
Patent
active
059881372
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a control apparatus for controlling a cylinder-injection spark-ignition internal combustion engine, and more particularly, to a control apparatus for minimizing deterioration in drivability or fuel efficiency when a change occurs in the values of parameters that are related to the occurrence of knocking, such as the properties of fuel supplied to the engine.
BACKGROUND ART
In order to reduce harmful exhaust gas components or improve the fuel efficiency of a spark-ignition internal combustion engine mounted on a vehicle, there have recently been proposed various types of cylinder-injection gasoline engines, in which fuel is injected directly into the combustion chamber, in place of conventional manifold-injection engines.
In cylinder-injection gasoline engines, fuel is injected from a fuel injection valve to, for example, a cavity formed on the top of a piston so that, at the time of ignition, an air-fuel mixture having an air-fuel ratio close to the stoichiometric air-fuel ratio may be produced around the spark plug. This permits firing even with an air-fuel mixture, which is lean as a whole, thereby reducing the emission amounts of CO and HC, and also greatly improves the fuel efficiency during idling or low-load travel.
In this type of gasoline engine, moreover, injection mode is switched between a compression stroke injection mode and a suction stroke injection mode in accordance with an operating state of the engine, that is, engine load. Specifically, during a low-load operation, the compression stroke injection mode in which fuel is injected mainly during the compression stroke is selected to produce a mixture with an air-fuel ratio close to the stoichiometric air-fuel ratio locally around the spark plug or in the cavity, so that satisfactory stratified combustion may take place even with an air-fuel mixture, which is lean as a whole (this injection mode is referred to as compression-lean mode). Since, in the compression stroke injection mode, engine operation is achievable even if the overall air-fuel ratio is set to a large value (e.g., to an air-fuel ratio of "40"), fresh intake air and recirculated exhaust gas (EGR) can be supplied to the cylinder in large quantities, whereby the pumping loss is reduced, thereby remarkably improving the fuel efficiency. It is, therefore, desirable that the region of engine operation in the compression stroke injection mode should be expanded as large as possible to improve the fuel efficiency.
In medium- and high-load operations, on the other hand, the suction stroke injection mode, in which fuel is injected mainly during the suction stroke, is selected to produce a mixture having a uniform air-fuel ratio throughout the combustion chamber, so that the output required during acceleration or high-speed travel can be obtained by burning a large quantity of fuel, as in manifold-injection gasoline engines (Where the air-fuel ratio is controlled to a value in the vicinity of the stoichiometric air-fuel ratio, the injection mode is called stoichiometric-feedback (S-FB) mode, and where the air-fuel ratio is controlled to a leaner side (e.g., to an air-fuel ratio of about "22") than the stoichiometric air-fuel ratio, the injection mode is called suction-lean mode).
In manifold-injection gasoline engines, the combustible air-fuel ratio zone (lean-burn zone) of the mixture supplied to the engine is narrow, and therefore, almost constant output torque is obtained in the entire combustible air-fuel ratio zone insofar as the volumetric efficiency E.sub.v is constant. Namely, the engine output torque is determined substantially uniquely by the volumetric efficiency E.sub.v. Accordingly, in manifold-injection gasoline engines, the values of engine control parameters, such as a target air-fuel ratio and target ignition timing, are set based on the volumetric efficiency E.sub.v obtained from the output of an air flow sensor, for example, and the engine operation is controlled in accordance with the control parameter values.
On t
REFERENCES:
patent: 5313920 (1994-05-01), Matsushita
patent: 5870992 (1999-02-01), Kamura et al.
patent: 5873344 (1999-02-01), Kudou et al.
patent: 5875756 (1999-03-01), Kamura et al.
patent: 5878711 (1999-03-01), Kamura et al.
Tamura Hiroki
Tashima Kazuchika
Kwon John
Mitsubishi Jidosha Kogyo Kabushiki Kaisha
LandOfFree
Controller of in-cylinder injection spark ignition internal comb does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Controller of in-cylinder injection spark ignition internal comb, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Controller of in-cylinder injection spark ignition internal comb will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1209595