Internal-combustion engines – Combustion chamber means combined with air-fuel mixture... – Stratification in combustion chamber
Reexamination Certificate
1999-03-11
2001-11-13
Kwon, John (Department: 3747)
Internal-combustion engines
Combustion chamber means combined with air-fuel mixture...
Stratification in combustion chamber
C123S295000, C123S300000, C123S305000
Reexamination Certificate
active
06314939
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates generally to direct gasoline-injected internal combustion engines, and more particularly, to reducing soot formation and improving running quality of such engines.
Known internal combustion engines include a cylinder block having a crankcase. In a v-type engine, two banks of cylinders extend radially from the crankcase. Each cylinder bank in a v-type six cylinder engine, for example, has three cylinders. In addition, and in a direct gasoline injected engine, gasoline is injected directly into each cylinder.
The direct burning of gasoline droplets in a cylinder causes soot formation due to burning unvaporized gasoline in the cylinder, and poorer fuel-air mixture formation as compared to a homogenous charge engine. At idle speeds, soot formation and mixture formation are not significant because the injected fuel quantities are small as compared to the injected quantities at higher speeds, and because the gasoline droplets are small due to later injection timing into higher cylinder pressures. As the injection timing becomes earlier and fueling rates increase to a maximum rate just before the transition from stratified combustion to homogenous combustion, soot formation and mixture formation adversely impact engine operation.
Known engines typically are operated with a step jump in injection timing to avoid substantial soot generation and improve mixture formation. Particularly, at a predetermined engine RPM, a small movement in the throttle causes a step increase, rather than a smooth increase, in the engine RPM. The step increase in RPM provides that the engine converts from stratified combustion to homogeneous combustion with very little throttle movement, which facilitates reducing heavy soot formation and improves mixture formation.
In marine engines, although such a step increase engine RPM avoids heavy soot production and improves mixture formation, the step increase in engine RPM results in a potentially objectionable increase or decrease in boat speed with very little throttle movement. It would be desirable to provide methods and apparatus for engine operation so that heavy soot production is avoided yet allows smooth engine acceleration and deceleration without significant engine RPM increases and decreases with small throttle movements.
BRIEF SUMMARY OF THE INVENTION
These and other objects may be attained by engine control apparatus and methods wherein heavy soot production is avoided yet smooth engine acceleration and deceleration are provided without significant engine RPM increases and decreases with small throttle movements. In one embodiment, once the fuel injection angle reaches the angle at which soot formation begins, one or more cylinders are controlled to operate with later injection angles and lower fueling, which results in lower torque production and lower soot formation, while at the same time the remaining cylinders are set to operate with advanced injection angles and higher fueling, which results in a homogenous mixture of air and fuel, higher torque, and also lower soot formation.
Therefore, for a first range of throttle positions, all cylinders operate in a stratified combustion mode. When the soot zone is reached, as determined based on throttle position, then some or at least one of the cylinders operate in a homogenous combustion mode and some or at least one of the cylinders operate in a stratified combustion mode. Once all the cylinders have skipped over the soot zone injection angles, then all the cylinders operate in a homogenous combustion mode.
The above described control strategy is sometimes referred to herein as an injection angle skip strategy because the injection angles corresponding to the heavy soot formation zone are skipped. Rather than all cylinders being controlled to skip over the soot zone at one time with very little throttle movement, each cylinder is controlled to skip over the soot zone at different throttle positions. By controlling the cylinders to skip the injection angles corresponding to the soot zone as described above, heavy soot production is avoided yet smooth engine acceleration and deceleration are provided without significant engine RPM increases and decreases with small throttle movements.
REFERENCES:
patent: 4543930 (1985-10-01), Baker
patent: 4641617 (1987-02-01), Aoyama et al.
patent: 5050557 (1991-09-01), Ishida et al.
patent: 5078107 (1992-01-01), Morikawa
patent: 5086737 (1992-02-01), Watanabe et al.
patent: 5094210 (1992-03-01), Endres et al.
patent: 5333583 (1994-08-01), Matsuura
patent: 5553580 (1996-09-01), Ganoung
patent: 5603301 (1997-02-01), Sakurai et al.
patent: 5666916 (1997-09-01), Fujieda et al.
patent: 5755198 (1998-05-01), Grob et al.
patent: 5832901 (1998-11-01), Yoshida et al.
patent: 5875761 (1999-03-01), Fujieda et al.
patent: 5894726 (1999-04-01), Monnier
patent: 5915353 (1999-06-01), Matsumura
patent: 5937822 (1999-08-01), Nakajima
patent: 5950603 (1999-09-01), Cook et al.
patent: 5954023 (1999-09-01), Mizuno et al.
patent: 5967114 (1999-10-01), Yasuoka
patent: 5983853 (1999-11-01), Roessler et al.
patent: 197 58 018 A1 (1999-07-01), None
patent: 0 898 069 A2 (1999-02-01), None
patent: 2 755 186 A1 (1996-10-01), None
patent: 6330738 (1994-11-01), None
Binversie Gregory J.
Craft Todd D.
Koerner Scott A.
Armstrong Teasdale LLP
Kwon John
Outboard Marine Corporation
Vo Hieu T.
LandOfFree
Methods and apparatus for controlling engine operation does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Methods and apparatus for controlling engine operation, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Methods and apparatus for controlling engine operation will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2601601