Internal-combustion engines – Engine speed regulator – Having condition responsive means with engine being part of...
Reexamination Certificate
2002-03-12
2003-11-11
Solis, Erick (Department: 3747)
Internal-combustion engines
Engine speed regulator
Having condition responsive means with engine being part of...
C123S542000, C123S179180, C123S14250R
Reexamination Certificate
active
06644272
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a diesel engine.
2. Description of Related Art
Conventionally, a flow adjuster for adjusting the flow of intake air or exhaust is provided at the halfway of intake channel or exhaust channel of a diesel engine to throttle the intake flow or the exhaust flow, thereby accelerating warm-up operation in starting engine.
Specifically, when intake flow is throttled by the flow adjuster, the intake air supplied from the outside into the cylinder of the diesel engine and the exhaust discharged from the cylinder is decreased, less heat quantity is lost by the intake-air of which temperature is low as compared to the temperature in the cylinder, and more heat quantity can be given in the cylinder by the exhaust, so that the in-cylinder temperature can be easily raised, thereby accelerating ignition and complete combustion of the fuel.
On the other hand, when the exhaust flow is throttled by the flow adjuster, more high-temperature exhaust can be retained in the cylinder without being discharged and the intake air supplied into the cylinder can be decreased as in throttling the intake air, the inside of the cylinder can be warmed by the temperature of the exhaust and less heat quantity is lost by the intake air, so that in-cylinder temperature can be easily raised and ignition and complete combustion of the fuel can be enhanced.
In the above-described diesel engine, the intake air or exhaust is throttled by the flow adjuster in starting the engine and the throttle of the intake air or the exhaust is released after starting the engine.
However, when no load or small load is applied to the engine after starting the engine where engine speed is high as compared to engine start time, small amount of fuel is supplied into the cylinder on account of small load and combustion time per one time for respective cylinders becomes short on account of high engine speed.
Accordingly, when no or small load is applied to the engine after starting the engine, ignition and complete combustion of fuel are difficult to be caused, and all the cylinders are not ignited, thus causing engine hunching and discharge of non-combusted fuel from the cylinder as white smoke.
Especially, when diesel engine is used as a motor of construction equipment or power generator, diesel engine is often operated in high-idle condition where no load or small load is applied to the engine and engine speed is extremely high. Under such condition, engine hunching and white smoke are likely to be generated.
Further, when a diesel engine is started in cold area or time, since the inside of the cylinder is extremely cold and the temperature of the intake air is substantially low, the possibility of engine hunching and discharge of white smoke are further increased.
Further, in a diesel engine having an intake air charger, the compression ratio is often set smaller than a diesel engine having no intake air charger in order to increase charged air pressure ratio thereof. In this case, the in-cylinder temperature is further difficult to be increased on account of small compression ratio and ignition of fuel and complete combustion are difficult to be occurred. Accordingly, all-cylinder ignition becomes difficult and the possibility of engine hunching and white smoke discharge are further increased.
In recent years, through emulsion fuel composed of mixture of fuel and water has come to be used for decreasing toxic substance in the exhaust such as nitrogen oxide, so-called NOx, of the diesel engine, such emulsion fuel is inferior in selfignition property on account of water. When such difficult-to-be ignited emulsion fuel is used in an engine, fuel ignition and complete combustion become difficult, thereby causing engine hunching and white smoke discharge.
SUMMARY OF THE INVENTION
An object of the present invention is to reduce the possibility of engine hunching and to greatly decrease the discharge of white smoke in a diesel engine.
Incidentally, the term of first to ninth predetermined periods are used in the description of the present invention, of which meaning will be easily understood with reference to FIG.
18
.
In order to achieve an object of the present invention, a diesel engine according to an aspect of the present invention includes: a combustion stabilization assist for enhancing stabilization of combustion of fuel supplied into a combustion chamber, the combustion stabilization assist being actuated for a predetermined period in accordance with operating condition of the diesel engine, in which the predetermined period is either one of a first predetermined period from starting the diesel engine until the diesel engine reaches a neighborhood of high-idle condition and a second predetermined period from a pre-high-idle step before the condition of the diesel engine reaches the high-idle condition until the condition of the diesel engine reaches the neighborhood of the high-idle condition.
The high-idle condition refers to a situation that the load applied to the engine is low (including zero) and engine speed is high. The pre-high-idle step may be any time after starting the engine and below the high-idle condition.
The neighborhood of high-idle condition refers to a situation that the load applied to the engine is low (including zero) and the engine speed is around the high-idle rotation speed, where the engine speed may approximately coincide with the high-idle rotation speed, may be slightly lower than the high-idle rotation speed, or may be slightly higher than the high-idle rotation speed.
Accordingly to the above arrangement, since the combustion stabilization assist is actuated during either one of the first predetermined period and the second predetermined period, the combustion stabilization assist is actuated at least from the pre-high-idle step until the neighborhood of the high-idle condition of the diesel engine. In other words, since the combustion stabilization assist is actuated during the period where the fuel amount supplied into the combustion chamber is low on account of zero load or low load applied to the diesel engine and fuel combustion time is short on account of high engine speed, the fuel combustion during the period can be enhanced. Accordingly, even when the fuel amount supplied into the combustion chamber is small and combustion time is short, ignition and complete combustion of the fuel can be enhanced, thereby greatly reducing the possibility of engine hunching and white smoke discharge.
Further, when the first predetermined period is used as the predetermined period, the combustion stabilization assist is actuated from the start of the engine. In other words, since the combustion stabilization assist is actuated when the fuel amount supplied into the combustion chamber is small on account of zero or low load applied to the engine and the temperature inside the combustion chamber is low, the ignition and complete combustion of the fuel can be sufficiently enhanced, thereby improving startability of the diesel engine.
A diesel engine according to another aspect of the present invention includes: a combustion stabilization assist for enhancing stabilization of combustion of fuel supplied into a combustion chamber, the combustion stabilization assist being actuated for a predetermined period in accordance with operating condition of the diesel engine, in which the predetermined period is either one of a third predetermined period from starting the diesel engine until a predetermined time has elapsed after the diesel engine reaches a high-idle condition and a fourth predetermined period from a pre-high-idle step before the condition of the diesel engine reaches the high-idle condition until a predetermined time has elapsed after the diesel engine reaches the high-idle condition, and/or either one of a fifth predetermined period from starting the diesel engine until a predetermined load is applied to the engine after the diesel engine reaches the high-idle condition and a sixth predetermined period from a pre-hig
Furukawa Hideo
Okazaki Tooru
Sakasai Takashi
Sato Hiroyasu
Armstrong, Westerman & Hattoi, LLP
Komatsu Ltd.
Solis Erick
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