Internal-combustion engines – Combustion chamber means having fuel injection only – Combustible mixture stratification means
Reexamination Certificate
2002-11-21
2004-06-01
Gimie, Mahmoud (Department: 3747)
Internal-combustion engines
Combustion chamber means having fuel injection only
Combustible mixture stratification means
C123S305000
Reexamination Certificate
active
06742492
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an apparatus and a method for controlling a diesel engine.
BACKGROUND INFORMATION
There is known an earlier diesel engine of a direct fuel injection type where a combustion temperature in a combustion chamber is lowered by introducing heavy EGR, known as exhaust gas recirculation, back into the combustion chamber. Under this approach, an ignition delay period is largely prolonged so as to build a heat release pattern with one-step combustion shape (the ignition delay period is longer than a fuel injection period) called a low temperature-premixed combustion, and thereby, NOx and smokes are reduced at the same time.
In this engine, the premixing is further expanded by dispersing fuel into the entire combustion chamber due to formation of a high swirl in the combustion chamber and a cylindrical shape of the combustion chamber (see Japanese Unexamined Patent Publication No. 8-86251).
SUMMARY OF THE INVENTION
However, in the above diesel engine, the ignition delay period is too long compared to the fuel injection period either under relatively colder engine conditions or a lowered compression ratio.
As a result, when time from a fuel injection completion to an ignition start becomes too long, fuel is dispersed too much into the entire combustion chamber and an equivalent ratio of fuel to air in the vicinity of a cylinder center (in a piston cavity) becomes extremely lean. Therefore, an emission quantity of unburned hydrocarbons (HC) is increased.
One aspect of the invention provides an apparatus for controlling a diesel engine where a combustion temperature in a combustion chamber is lowered, and an ignition delay period is largely prolonged so as to build a heat release pattern with one-step combustion shape, as well as an equivalent ratio distribution in the combustion chamber at an ignition start is controlled such that the equivalent ratio in the vicinity of a cylinder center is relatively richer compared with that in the vicinity of a cylinder wall and the equivalent ratio gradually changes from the cylinder center to the cylinder wall.
These and other objects and features of this invention will be understood from the following description with accompanying drawings.
REFERENCES:
patent: 5992372 (1999-11-01), Nakajima
patent: 6390057 (2002-05-01), Yoshizawa et al.
patent: 2864896 (1995-01-01), None
patent: 8-086251 (1996-04-01), None
Foley & Lardner LLP
Gimie Mahmoud
Nissan Motor Co,. Ltd.
LandOfFree
Apparatus and a method for controlling a diesel engine does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus and a method for controlling a diesel engine, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus and a method for controlling a diesel engine will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3314124