JP4132772B2 - Ship propulsion engine control system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an engine control device for a ship propulsion device.
[0002]
[Prior art]
A ship propulsion device provided in a ship is equipped with an engine, and propellers are rotated by the power of the engine to obtain a propulsive force. Some of these marine propulsion devices include an engine control device that controls the fuel injection amount based on the intake pressure, the throttle opening, and the engine speed.
[0003]
[Problems to be solved by the invention]
For example, in an engine mounted on a vehicle, the normal range is low speed and low load, and even if lean burn is performed at high speed and high load, the fuel consumption reduction rate is low, so lean burn is performed in the low speed and low load range, and lean at high speed and high load. Not burned.
[0004]
By the way, an engine mounted on a ship propulsion device is operated at a high speed and a high load immediately after the start of cruising, and the normal range is a high speed and a high load. large.
[0005]
In this way, it is conceivable to perform lean burn to improve fuel efficiency with an engine mounted on a marine propulsion device, but in order to achieve both stable combustion and NOx reduction, an air-fuel ratio sensor is installed in the exhaust passage of the engine. It is desirable to arrange and accurately control the fuel injection amount based on the air-fuel ratio by feedback control.
[0006]
However, the marine vessel propulsion device is underwater exhaust, and the pressure of the air-fuel ratio sensor installation portion changes depending on the traveling state, and this affects the output of the air-fuel ratio sensor. Further, the exhaust temperature change range is wide from idle to full load, and the element temperature of the full-range air-fuel ratio sensor changes with the exhaust temperature change, thereby affecting the output of the air-fuel ratio sensor.
[0007]
The present invention has been made in view of the above points, and provides an engine control device for a marine propulsion device that performs feedback control over the entire region of the air-fuel ratio and that can perform accurate air-fuel ratio control over the entire region through correction. It is aimed.
[0008]
[Means for Solving the Problems]
In order to solve the above-described problems and achieve the object, the present invention is configured as follows.
[0009]
The invention according to claim 1 is provided with an intake pressure detecting means for detecting intake pressure, a throttle opening detecting means for detecting the throttle opening, and an engine rotational speed detecting means for detecting the engine rotational speed. In a four-stroke engine control device for a ship propulsion device that controls the fuel injection amount based on the atmospheric pressure, the throttle opening, and the engine rotation speed,
The engine exhaust passage includes an air-fuel ratio detecting means for detecting an air-fuel ratio, and an exhaust pressure detecting means for detecting an exhaust pressure.
Feedback control of the fuel injection amount based on the air-fuel ratio, and correction based on the exhaust pressure,
An exhaust passage of the engine extends downward from the engine through an exhaust guide and an oil pan disposed below the engine,
An exhaust expansion chamber is formed in a portion below the exhaust guide and the oil pan of the exhaust passage,
A detection passage is provided in communication with the exhaust expansion chamber;
The detection passage is formed narrower than a portion of the exhaust passage located on the engine side with respect to the exhaust expansion chamber,
The exhaust pressure detection means is disposed in the detection passage,
The engine control device for a marine propulsion device, wherein the detection passage extends through the exhaust guide and the oil pan to the engine. ].
[0010]
According to the first aspect of the present invention, the fuel injection amount is feedback-controlled based on the air-fuel ratio, and the air-fuel ratio detection means corrects based on the exhaust pressure even if the output is affected by the measured pressure. By doing so, more accurate air-fuel ratio control is possible in the entire region, and both stable combustion and NOx reduction can be achieved. The exhaust pressure detection means is disposed in a detection passage provided in communication with an exhaust expansion chamber formed in the exhaust passage of the engine, and the detection passage extends through the exhaust guide disposed under the engine to the engine. As a result, the exhaust passage expands and the temperature drops because the detection passage is long, and the heat resistance required for the exhaust pressure detection means decreases, and the exhaust pressure detection means is installed in a place where it is difficult to submerge. In addition, exhaust pressure detection means can be installed where it can be seen from the outside, facilitating maintenance and inspection.
[0013]
The invention according to claim 2 is provided with “an intake pressure detecting means for detecting an intake pressure, a throttle opening detecting means for detecting a throttle opening, and an engine rotational speed detecting means for detecting an engine rotational speed. In a four-stroke engine control device for a ship propulsion device that controls the fuel injection amount based on the atmospheric pressure, the throttle opening, and the engine rotation speed,
The engine exhaust passage includes an air-fuel ratio detecting means for detecting an air-fuel ratio, an exhaust pressure detecting means for detecting an exhaust pressure, and an exhaust temperature detecting means for detecting an exhaust temperature,
Feedback control of the fuel injection amount based on the air-fuel ratio, and correction based on the exhaust pressure and the exhaust temperature,
An exhaust passage of the engine extends downward from the engine through an exhaust guide and an oil pan disposed below the engine,
An exhaust expansion chamber is formed in a portion below the exhaust guide and the oil pan of the exhaust passage,
A detection passage is provided in communication with the exhaust expansion chamber;
The detection passage is formed narrower than a portion of the exhaust passage located on the engine side with respect to the exhaust expansion chamber,
The exhaust pressure detection means is disposed in the detection passage,
The engine control device for a marine propulsion device, wherein the detection passage extends through the exhaust guide and the oil pan to the engine. ].
[0014]
According to the second aspect of the present invention, the fuel injection amount is feedback-controlled based on the air-fuel ratio, and even if the output of the air-fuel ratio detecting means is influenced by the measured pressure, the air-fuel ratio detecting means Even if the output is affected by the element temperature, correction based on the exhaust pressure and the exhaust temperature makes it possible to perform more accurate air-fuel ratio control in the entire region and achieve both stable combustion and NOx reduction. it can. The exhaust pressure detection means is disposed in a detection passage provided in communication with an exhaust expansion chamber formed in the exhaust passage of the engine, and the detection passage extends through the exhaust guide disposed under the engine to the engine. As a result, the exhaust passage expands and the temperature drops because the detection passage is long, and the heat resistance required for the exhaust pressure detection means decreases, and the exhaust pressure detection means is installed in a place where it is difficult to submerge. In addition, exhaust pressure detection means can be installed where it can be seen from the outside, facilitating maintenance and inspection.
[0017]
According to a third aspect of the present invention, “the engine control device for a marine vessel propulsion device according to the first or second aspect, wherein the exhaust gas temperature detecting means is disposed in the vicinity of the air-fuel ratio detecting means. ].
[0018]
According to the third aspect of the present invention, since the exhaust gas temperature detecting means is disposed close to the air fuel ratio detecting means, the exhaust gas temperature detecting means can accurately estimate the element temperature of the air fuel ratio detecting means.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of an engine control device for a marine vessel propulsion apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a side view of an outboard motor, and FIG. 2 is a schematic configuration diagram of an engine control device of a ship propulsion device.
[0020]
In this embodiment, an outboard motor is shown as a ship propulsion device mounted on a ship, but the present invention is similarly applied to an inboard motor. The outboard motor 1 is supported on the stern 2a of the hull 2 through a clamp bracket 3 so as to be swingable up and down and left and right. The outboard motor 1 has a top cowling 4a, a bottom cowling 4b, an upper case 5 and a lower case 6. An engine 7 is disposed in the top cowling 4a and the bottom cowling 4b, and in the upper case 5 and the lower case 6. The propulsion unit 8 is disposed.
[0021]
The engine 7 is a four-cycle in-line four-cylinder engine, and the propulsion unit 8 is driven by the engine 7. The propulsion unit 8 has a configuration in which a propulsion shaft 11 is connected to a lower end of a drive shaft 9 extending in a vertical direction via a bevel gear mechanism 10 and a propeller 12 is coupled to a rear end of the propulsion shaft 11.
[0022]
In this outboard motor 1, a shift cable 60 is connected to a shift operation shaft 62 via a slider 64. By operating the shift cable 60 by a remote shift operation, the slider 64 moves and operates the shift operation shaft 62 connected via a link mechanism (not shown), whereby the shift switching means 63 causes the bevel gear mechanism 10 to move. Control, forward, neutral, reverse shift switching is performed.
[0023]
The engine 7 is disposed on the exhaust guide 13 and is configured by vertically disposing the crankshaft 20 so as to be substantially vertical when traveling, and the upper end of the drive shaft 9 is connected to the lower end of the crankshaft 20. ing.
[0024]
The engine 7 has a crankshaft 20 supported by a cylinder block 21 and a crankcase 22. An oil pan 90 is suspended and supported on the lower surface of the exhaust guide 13. A cylinder head 24 is fastened to the cylinder block 21, and a head cover 25 is attached to the cylinder head 24.
[0025]
The piston 50 provided in the cylinder block 21 so as to be able to reciprocate is connected to the crankshaft 20 via a connecting rod 51, and the crankshaft 20 rotates via the connecting rod 51 by the reciprocating motion of the piston 50.
[0026]
A combustion chamber 52 is formed by the cylinder block 21, the piston 50 and the cylinder head 24, and a spark plug 53 is attached to the cylinder head 24 so as to face the combustion chamber 52. The cylinder head 24 is formed with an intake passage 45 and an exhaust passage 46 that open to the combustion chamber 52.
[0027]
Camshafts 26a and 26b of a valve operating mechanism are pivotally supported on the cylinder head 24, and the rotational force of the crankshaft 20 is transmitted by a timing belt (not shown), and the cams 26a1 and 26b1 take in air by the rotation of the camshafts 26a and 26b. The valve 30 and the exhaust valve 31 are driven to open and close the intake passage 45 and the exhaust passage 46.
[0028]
A surge tank 40 is disposed in the engine 7 in the forward direction of the hull. A throttle body 42 is connected to the upstream side of the surge tank 40, and the upstream side of the surge tank 40 is connected to an intake passage 45 of the cylinder head 24 via an intake pipe 41. The cylinder head 24 is provided with injectors 43 corresponding to the respective cylinders, and fuel is supplied to the intake passage 45 by the injectors 43.
[0029]
The throttle body 42 is provided with throttle opening degree detecting means for detecting the throttle opening degree constituted by the idle speed control valve 420, the throttle 421 and the throttle position sensor S1, and sends the throttle opening degree information to the control unit ECU. The control unit ECU controls the idle speed control valve 420 to perform a stable idle operation.
[0030]
The surge tank 40 is provided with a pressure sensor S2 and an intake air temperature sensor S3, and sends intake pressure information and intake air temperature information to the control unit ECU. The pressure sensor S2 constitutes intake pressure detection means for detecting intake pressure.
[0031]
The control device ECU controls the injector 43 according to the operating state. Fuel is supplied to the injector 43 from the fuel supply device 48. The fuel supply device 48 includes a fuel tank 480, a filter 481, a low pressure pump 485, a vapor separator 482, a high pressure pump 483, and a pressure adjustment device 484.
[0032]
By driving the low-pressure pump 485, fuel is supplied from the fuel tank 480 to the vapor separator 482 via the filter 481. The high-pressure pump 483 is disposed in the vapor separator 482 and supplies the pressurized fuel to the injector 43 through the supply pipes 43 a and 43 b by driving the high-pressure pump 483.
[0033]
Excess fuel is returned to the vapor separator 482 via the return pipe 43c, the pressure adjusting device 484, and the return pipe 43d. The pressure adjusting device 484 is connected to the surge tank 40 via the connecting pipe 484a, and operates with intake pressure to return excess fuel to the vapor separator 482.
[0034]
The cylinder head 24 is provided with a water temperature sensor S4 and a cam angle sensor S5, and sends engine water temperature information and cam angle information to the control unit ECU. The cam angle sensor S5 constitutes a cam angle detecting means for detecting the cam angle of supply / exhaust. Further, the exhaust passage 46 is provided with an A / F sensor S6, and sends A / F information to the control unit ECU.
[0035]
The control device ECU is provided with an engine rotation speed detecting means 49, which calculates based on the cam angle information and detects the engine rotation speed. The engine 7 is provided with an ignition device 55. The ignition device 55 includes a power transistor 550 and an ignition coil 551, and operates the power transistor 550 under the control of the control device ECU to cause the ignition plug 53 to spark through the ignition coil 551 according to the operating state.
[0036]
The engine control device for a marine vessel propulsion device according to this embodiment is configured as shown in FIGS. 3 to 6, FIG. 3 is a schematic configuration diagram of an engine exhaust system, and FIG. 4 is a diagram showing characteristics of an air-fuel ratio sensor. FIG. 5 is a diagram showing the influence of the output of the air-fuel ratio sensor due to the pressure, and FIG. 6 is a diagram showing the influence of the output of the air-fuel ratio sensor due to the element temperature.
[0037]
In the exhaust system of the engine 7 of this embodiment, as shown in FIG. 3, an exhaust passage 46 assembled from each cylinder is formed so as to penetrate the exhaust guide 13 and the oil pan 90 and communicate with the exhaust expansion chamber 80. Underwater exhaust is performed.
[0038]
In the exhaust passage 46, an air-fuel ratio sensor S6 that is an air-fuel ratio detection unit is disposed, and an exhaust temperature sensor S10 that is an exhaust temperature detection unit is disposed in the vicinity of the air-fuel ratio sensor S6. Further, a detection passage 81 is provided in communication with an exhaust expansion chamber 80 formed in the exhaust passage 46 of the engine 7, and an exhaust pressure sensor S 11 serving as an exhaust pressure detection means is disposed in the detection passage 81.
[0039]
The exhaust temperature information from the exhaust temperature sensor S10 and the exhaust pressure information from the exhaust pressure sensor S11 are sent to the control unit ECU.
[0040]
The control device ECU controls the fuel injection amount by the injector 43 based on the intake pressure, the throttle opening, and the engine speed. The control of the fuel injection amount performs feedback control of the fuel injection amount based on the air-fuel ratio, and performs correction based on the exhaust pressure and the exhaust temperature.
[0041]
That is, the air-fuel ratio sensor S6 has a characteristic that the sensor output (V) changes according to the air-fuel ratio (A / F) as shown in FIG. In the air-fuel ratio sensor S6, as shown in FIG. 5, the output of the air-fuel ratio sensor is affected by the pressure. Although the output is set to 100% at the reference pressure, for example, when the pressure is lower than the reference pressure, the output becomes small, and therefore, the fuel injection amount tends to be reduced from the reference, and the output is shifted to the lean side. Further, for example, when the pressure is higher than the reference pressure, the output is increased, and therefore, the fuel injection amount tends to be increased from the reference, and the rich side is deviated.
[0042]
In the air-fuel ratio sensor S6, as shown in FIG. 6, the output of the air-fuel ratio sensor is affected by the element temperature. The output is set to 100% at the reference element temperature. For example, when the element temperature is lower than the reference element temperature, the output becomes small, and therefore, the fuel injection amount tends to decrease from the reference, and the output is shifted to the lean side. Further, for example, when the element temperature is higher than the reference element temperature, the output increases, and therefore, the fuel injection amount tends to increase from the reference, and the rich side is deviated.
[0043]
As described above, the control of the fuel injection amount feedback-controls the fuel injection amount based on the air-fuel ratio and corrects the deviation based on the exhaust pressure and the exhaust temperature, so that the output of the air-fuel ratio sensor S6 is influenced by the measured pressure. Even if the output of the air-fuel ratio sensor S6 is affected by the element temperature, more accurate air-fuel ratio control is possible in all regions, and both stable combustion and NOx reduction can be achieved. .
[0044]
Further, the exhaust pressure sensor S11 is disposed in the detection passage 81 in communication with the exhaust expansion chamber 80 formed in the exhaust passage 46 of the engine 7, so that the exhaust expands in the exhaust expansion chamber 80 and the temperature is lowered. The operating temperature of the exhaust pressure sensor S11 is lowered, and the heat resistance required for the exhaust pressure sensor S11 is reduced. Further, the exhaust pressure sensor S11 can be installed in a place where it is difficult to be submerged, and durability is improved. Further, the exhaust pressure sensor S11 can be installed where it can be seen from the outside, and maintenance inspection becomes easy.
[0045]
Further, since the exhaust temperature sensor S10 is disposed in the vicinity of the air-fuel ratio sensor S6, the exhaust temperature sensor S10 can accurately estimate the element temperature of the air-fuel ratio sensor S6, and the air-fuel ratio sensor S6 is not highly accurate. The standard can be used, and the cost can be reduced accordingly.
[0046]
【The invention's effect】
As described above, in the first aspect of the present invention, the fuel injection amount is feedback-controlled based on the air-fuel ratio, and the air-fuel ratio detection means is based on the exhaust pressure even if the output is influenced by the measured pressure. By performing the correction, more accurate air-fuel ratio control is possible in the entire region, and both stable combustion and NOx reduction can be achieved. The exhaust pressure detection means is disposed in a detection passage provided in communication with an exhaust expansion chamber formed in the exhaust passage of the engine, and the detection passage extends through the exhaust guide disposed under the engine to the engine. As a result, the exhaust passage expands and the temperature drops because the detection passage is long, and the heat resistance required for the exhaust pressure detection means decreases, and the exhaust pressure detection means is installed in a place where it is difficult to submerge. In addition, exhaust pressure detection means can be installed where it can be seen from the outside, facilitating maintenance and inspection.
[0048]
According to the second aspect of the present invention, the fuel injection amount is feedback-controlled based on the air-fuel ratio, and even if the output of the air-fuel ratio detecting means is influenced by the measured pressure, the air-fuel ratio detecting means is controlled by the element temperature. Even if the output is affected, by performing correction based on the exhaust pressure and the exhaust temperature, more accurate air-fuel ratio control is possible in the entire region, and both stable combustion and NOx reduction can be achieved. The exhaust pressure detection means is disposed in a detection passage provided in communication with an exhaust expansion chamber formed in the exhaust passage of the engine, and the detection passage extends through the exhaust guide disposed under the engine to the engine. As a result, the exhaust passage expands and the temperature drops because the detection passage is long, and the heat resistance required for the exhaust pressure detection means decreases, and the exhaust pressure detection means is installed in a place where it is difficult to submerge. In addition, exhaust pressure detection means can be installed where it can be seen from the outside, facilitating maintenance and inspection.
[0050]
According to the third aspect of the present invention, the exhaust gas temperature detecting means is disposed close to the air / fuel ratio detecting means, so that the exhaust gas temperature detecting means can accurately estimate the element temperature of the air / fuel ratio detecting means.
[Brief description of the drawings]
FIG. 1 is a side view of an outboard motor.
FIG. 2 is a schematic configuration diagram of an engine control device for a ship propulsion device.
FIG. 3 is a schematic configuration diagram of an exhaust system of an engine.
FIG. 4 is a diagram showing characteristics of an air-fuel ratio sensor.
FIG. 5 is a diagram showing the influence of the output of the air-fuel ratio sensor due to pressure.
FIG. 6 is a diagram showing the influence of the output of the air-fuel ratio sensor due to the element temperature.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Outboard motor 7 Engine 13 Exhaust guide 43 Injector 46 Exhaust passage 80 Exhaust expansion chamber 81 Detection passage 90 Oil pan S6 Air-fuel ratio sensor S10 Exhaust temperature sensor S11 Exhaust pressure sensor ECU Controller

Claims (3)

An intake pressure detecting means for detecting the intake pressure, a throttle opening detecting means for detecting the throttle opening, and an engine rotational speed detecting means for detecting the engine rotational speed are provided, and the intake pressure, the throttle opening and the engine rotational speed are adjusted. In a four-stroke engine control device for a ship propulsion device that controls the fuel injection amount based on
The engine exhaust passage includes an air-fuel ratio detecting means for detecting an air-fuel ratio, and an exhaust pressure detecting means for detecting an exhaust pressure.
Feedback control of the fuel injection amount based on the air-fuel ratio, and correction based on the exhaust pressure,
An exhaust passage of the engine extends downward from the engine through an exhaust guide and an oil pan disposed below the engine,
An exhaust expansion chamber is formed in a portion below the exhaust guide and the oil pan of the exhaust passage,
A detection passage is provided in communication with the exhaust expansion chamber;
The detection passage is formed narrower than a portion of the exhaust passage located on the engine side with respect to the exhaust expansion chamber,
The exhaust pressure detection means is disposed in the detection passage,
The engine control device for a marine propulsion device, wherein the detection passage extends through the exhaust guide and the oil pan to the engine. An intake pressure detecting means for detecting the intake pressure, a throttle opening detecting means for detecting the throttle opening, and an engine rotational speed detecting means for detecting the engine rotational speed are provided, and the intake pressure, the throttle opening and the engine rotational speed are adjusted. In a four-stroke engine control device for a ship propulsion device that controls the fuel injection amount based on
The engine exhaust passage includes an air-fuel ratio detecting means for detecting an air-fuel ratio, an exhaust pressure detecting means for detecting an exhaust pressure, and an exhaust temperature detecting means for detecting an exhaust temperature,
Feedback control of the fuel injection amount based on the air-fuel ratio, and correction based on the exhaust pressure and the exhaust temperature,
An exhaust passage of the engine extends downward from the engine through an exhaust guide and an oil pan disposed below the engine,
An exhaust expansion chamber is formed in a portion below the exhaust guide and the oil pan of the exhaust passage,
A detection passage is provided in communication with the exhaust expansion chamber;
The detection passage is formed narrower than a portion of the exhaust passage located on the engine side with respect to the exhaust expansion chamber,
The exhaust pressure detection means is disposed in the detection passage,
The engine control device for a marine propulsion device, wherein the detection passage extends through the exhaust guide and the oil pan to the engine.   The engine control device for a marine vessel propulsion apparatus according to claim 1 or 2, wherein the exhaust gas temperature detection means is disposed in proximity to the air-fuel ratio detection means.

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