Internal-combustion engines – Charge forming device – Including means responsive to instantaneous change in engine...
Reexamination Certificate
1999-02-01
2001-01-09
Kwon, John (Department: 3747)
Internal-combustion engines
Charge forming device
Including means responsive to instantaneous change in engine...
Reexamination Certificate
active
06170465
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a driving control apparatus of an engine and a method therefor, which enables fuel injection amount to set to an optimal value and makes it possible to precisely control the fuel injection even in any type of cylinders.
Prior Art
In recent years, a fuel injection type engine mounted in a vehicle, a ship or the like is provided with a driving control apparatus for precisely controlling an amount of fuel injection. In a conventional driving control apparatus, the fuel injection amount is controlled in a manner such that an air/fuel ratio, i.e., a ratio of air to fuel to be supplied to the engine becomes an optimal value.
For example, there is a known driving control apparatus in which data such as throttle opening degree and engine revolution speed, and data from detection means such as O
2
sensor or the like mounted in an exhaust passage of the engine are input to control means (such as a computer), an intake air amount and the air/fuel ratio are calculated by this control means, and a feed-back control is conduced for correcting the fuel injection amount based on the calculated value.
According to such a driving control apparatus, since it is possible to always set an air/fuel ratio close to a theoretical air/fuel ratio, combustion efficiency is extremely enhanced, and the engine output is then enhanced. Further, since the injection amount of fuel can be suppressed to the necessary but minimum amount, this can contribute to reduction of the fuel consumption amount.
However, since the air/fuel ratio detecting means such as the O
2
sensor can detect only a value close to the theoretical air/furl ratio, the conventional driving control apparatus is preferable for a four-stroke-cycle engine in which four strokes, i.e., an intake stroke, a compression stroke, an explosion stroke and an exhaust stroke are substantially clearly distinguished, but is not preferable for a two-stroke-cycle engine. That is, in the case of the two-stroke-cycle engine, the above mentioned four strokes are overlapped, and especially in a scavenging stroke in which intake and exhaust are carried out simultaneously, there is generated a blow-through phenomenon in which intake mixture is discharged from an exhaust port as it is, and it is difficult to precisely detect the air/fuel ratio.
Further, in the case of an engine mounted in an outboard motor, its exhaust passage is formed extremely short irrespective of two-stroke-cycle engine or four-stroke-cycle engine, and the last exhaust port is opened into the water and thus, the water (salt water) enters in the exhaust passage. Therefore, the detection means such as O
2
sensor mounted in this portion is severely required to have heat-resistance, vibration-resistance, water-resistance, rust-resistance and the like, which is very expensive, is prone to be out of order and lacks reliability.
Further, as described above, since the last exhaust port of the engine of the outboard motor is opened into the water, a back pressure in the exhaust passage is largely varied in accordance with the sailing condition. Such a variation in a back pressure in the exhaust passage varies the intake air amount especially in a two-stroke-cycle engine. Therefore, even if the intake air amount is calculated from the throttle opening degree or the engine revolution speed, such a calculated value may be different from an actual value in many cases and for this reason also, it is difficult to precisely control the fuel injection.
Furthermore, in the case of a multi-cylinder engine of an outboard motor, since the length of the exhaust passage of each of the cylinders is different, the exhaust back pressure is also different, and a difference in the intake air amount in each of the cylinders is generated. Therefore, it is more difficult to precisely set the fuel injection amount.
SUMMARY OF THE INVENTION
The present invention has been accomplished to solve the problems and drawbacks encountered in the prior art mentioned above, and an object of the present invention is to provide a driving control apparatus of an engine capable of setting the fuel injection amount to the optimal value with a simple and low-priced structure in any of the two-stroke-cycle engine and four-stroke-cycle engine.
Another object of the present invention is to provide a driving control apparatus of an engine, which makes it possible to precisely control the fuel injection even in the multi-cylinder engine.
A further object of the present invention is to provide a driving control apparatus of an engine allowing a user to easily notice a trouble at an early stage when the engine broken down so that the engine is prevented from being used as it is and that the broken portion can be easily detected and repaired.
A still further object of the present invention is to provide a driving control apparatus of an engine, which makes it possible to indicate a driving state of the engine without providing specific indicating means, and to simplify a structure of the driving control apparatus.
A still further object of the present invention is to provide a driving control method of an engine capable of performing an improved engine operation by using the engine driving control apparatus mentioned above.
These and other objects can be achieved according to the present invention by providing, in one aspect, a driving control apparatus of an engine which generally comprises a cylinder head, a cylinder block, a cylinder assembly including a plurality of cylinders, a crank case including a crankshaft, an ignition member and a surge tank, which are operatively connected to each other, the cylinders carrying out compression, explosion, exhausting and scavenging strokes sequentially, the driving control apparatus comprising:
a detector means for detecting a position of an explosion stroke;
a detector means for detecting instantaneous rotation speed of the crankshaft; and
a control unit which receives input from the explosion stroke position detecting means and the rotation speed detecting means, the control unit including an element for judging a combustion state from an increasing rate of a rotation speed of the crankshaft in each explosion stroke, an element for intentionally increasing or reducing an amount of fuel injection and calculating variation in the combustion state and an element for correcting the amount of fuel injection so as to enhance the combustion state.
In a preferred embodiment, the control unit is programmed such that the judgement of the combustion state is made individually for each of the cylinders or is programmed such that abnormalities are indicated when at least one of the judged combustion state and an average value thereof is a numerical value indicative of abnormal combustion.
In another aspect, there is provided a driving control apparatus of an engine generally including a cylinder block into which a plurality of cylinders are disposed and a crank case is provided with a crankshaft, the cylinders carrying out compression, explosion, exhausting and scavenging strokes sequentially, the driving control apparatus comprising:
a detector means for detecting a driving state of the engine; and
a unit for converting various detection values detected by the driving state detecting means and various control values concerning the driving state of the engine into frequency and indicating the frequency to a meter or the like.
In a further aspect, there is provided a driving control method of an engine which generally includes a cylinder block into which a plurality of cylinders are disposed and a crank case provided with a crankshaft, the cylinders carrying out compression, explosion, exhausting and scavenging strokes sequentially, the driving control method comprising the steps of:
detecting a position of an explosion stroke of the cylinder;
detecting instantaneous rotation speed of the crankshaft; and
performing a control process in accordance with the explosion stroke position detection and the rotation speed detection, the contr
Finnegan, Henderson & Farabow, Garrett & Dunner, L.L.P
Kwon John
Suzuki Kabushiki Kaisha
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