JP2003120378A - Engine control device for ship propulsion unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure accurate air-fuel ratio control in a full range by effecting feedback control in terms of air-fuel ratio in a full range and also correction. SOLUTION: An engine control device for a ship propulsion unit comprises an intake pressure detecting means for detecting intake pressure, a throttle travel detecting means for detecting throttle travel and an engine speed detecting means for detecting engine speed, and controls fuel injection quantity depending on the intake pressure, throttle travel and engine speed. An exhaust passage 46 of an engine 7 is provided with an air-fuel ratio detecting means for detecting air-fuel ratio, an exhaust pressure detecting means for detecting exhaust pressure and an exhaust gas temperature detecting means for detecting exhaust gas temperature. The fuel injection quantity is feedback-controlled depending on the air-fuel ratio and is corrected depending on the exhaust pressure and exhaust gas temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine control device for a ship propulsion device.

[0002]

2. Description of the Related Art An engine is mounted on a ship propulsion device provided in a ship, and a propeller is rotated by the power of the engine to obtain a propulsive force. Some ship propulsion devices include an engine control device and control the fuel injection amount based on the intake pressure, the throttle opening, and the engine rotation speed.

[0003]

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 small.
Lean burn is performed in the low speed and low load area, and is not burned in the high speed and high load area.

By the way, the engine mounted on the 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. The reduction rate is large.

As described above, it is conceivable to use lean burn to improve fuel efficiency in an engine mounted on a ship propulsion system. However, in order to achieve both stable combustion and reduction of NOx, the exhaust passage of the engine must be empty. It is desirable to dispose a fuel ratio sensor and perform feedback control of the fuel injection amount based on the air-fuel ratio for accurate control.

However, the marine vessel propulsion device is an underwater exhaust system, and the pressure at the installation portion of the air-fuel ratio sensor changes depending on the running state, which affects the output of the air-fuel ratio sensor. Further, the variation range of the exhaust temperature from the idle to the full load is large, and the element temperature of the full-range air-fuel ratio sensor changes with the change of the exhaust temperature, which affects the output of the air-fuel ratio sensor.

The present invention has been made in view of the above points, and provides an engine control device for a marine propulsion device capable of performing feedback control with an air-fuel ratio in the entire region and further performing accurate air-fuel ratio control in the entire region by correction. The purpose is to do.

[0008]

In order to solve the above-mentioned problems and to achieve the object, the present invention has the following constitution.

According to a first aspect of the present invention, there is provided "intake pressure detecting means for detecting intake pressure, throttle opening detecting means for detecting throttle opening, and engine rotational speed detecting means for detecting engine rotational speed. An engine control device for a ship propulsion device that controls a fuel injection amount based on an intake pressure, a throttle opening degree, and an engine rotation speed, in an exhaust passage of the engine, an air-fuel ratio detecting means for detecting an air-fuel ratio,
An engine control device for a marine propulsion device, comprising: an exhaust pressure detection means for detecting an exhaust pressure, feedback controlling the fuel injection amount based on the air-fuel ratio, and performing correction based on the exhaust pressure. ].

According to the first 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 detection means is affected by the measured pressure, the exhaust pressure is changed. By performing the correction based on this, more accurate air-fuel ratio control can be performed in the entire region, and stable combustion and NOx reduction can both be achieved.

According to a second aspect of the present invention, there is provided "intake pressure detecting means for detecting intake pressure, throttle opening detecting means for detecting throttle opening, and engine rotational speed detecting means for detecting engine rotational speed. An engine control device for a ship propulsion device that controls a fuel injection amount based on an intake pressure, a throttle opening degree, and an engine rotation speed, in an exhaust passage of the engine, an air-fuel ratio detecting means for detecting an air-fuel ratio,
An engine control device for a marine propulsion device, comprising: an exhaust gas temperature detecting means for detecting an exhaust gas temperature, feedback controlling the fuel injection amount based on the air-fuel ratio, and performing correction based on the exhaust gas temperature. ].

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 affected by the element temperature, the exhaust temperature is changed. By performing the correction based on this, more accurate air-fuel ratio control can be performed in the entire region, and stable combustion and NOx reduction can both be achieved.

According to another aspect of the present invention, there is provided "intake pressure detecting means for detecting intake pressure, throttle opening detecting means for detecting throttle opening, and engine speed detecting means for detecting engine speed. In an engine control device for a ship propulsion device that controls a fuel injection amount based on an intake pressure, a throttle opening, and an engine speed, an air-fuel ratio detection unit that detects an air-fuel ratio in an exhaust passage of the engine,
Exhaust pressure detection means for detecting exhaust pressure and exhaust temperature detection means for detecting exhaust temperature are provided, and the fuel injection amount is feedback controlled based on the air-fuel ratio, and correction is performed based on the exhaust pressure and the exhaust temperature. An engine control device for a marine propulsion device, which is characterized by performing. ].

According to the third 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 affected by the measured pressure, the air-fuel ratio is also reduced. Even if the output of the detection means is affected by the element temperature, the correction is performed based on the exhaust pressure and the exhaust temperature, so that more accurate air-fuel ratio control is possible in all areas, and stable combustion and NOx reduction are both achieved. Can be made.

According to a fourth aspect of the present invention, "a detection passage is provided in communication with an exhaust expansion chamber formed in the exhaust passage of the engine, and the exhaust pressure detecting means is disposed in the detection passage. The engine control device for a marine vessel propulsion device according to claim 1 or claim 3. ].

According to the fourth aspect of the invention, the exhaust pressure detecting means is arranged in the detection passage so as to communicate with the exhaust expansion chamber formed in the exhaust passage of the engine, whereby the exhaust gas is expanded and the temperature is raised. The heat resistance required for the exhaust pressure detection means is lowered, and the exhaust pressure detection means can be installed in a place where it is difficult to submerge in water, and the exhaust pressure detection means can be installed in a place visible from the outside, facilitating maintenance and inspection. become.

According to a fifth aspect of the present invention, "the engine for a marine propulsion apparatus according to the second or third aspect is characterized in that the exhaust gas temperature detecting means is arranged close to the air-fuel ratio detecting means. Control device. ].

According to the fifth aspect of the present invention, the exhaust temperature detecting means is arranged close to the air-fuel ratio detecting means, so that the exhaust temperature detecting means can accurately estimate the element temperature of the air-fuel ratio detecting means. .

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an engine control device for a ship propulsion device 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 for a boat propulsion device.

In this embodiment, an outboard motor is shown as a ship propulsion device to be mounted on a ship, but the same applies to an inboard motor. The outboard motor 1 is supported on the stern 2a of the hull 2 via a clamp bracket 3 so as to be swingable vertically and horizontally. This outboard motor 1 has a top cowling 4a, a bottom cowling 4b, an upper case 5 and a lower case 6,
The engine 7 is arranged in the top cowling 4a and the bottom cowling 4b, and the propulsion unit 8 is arranged in the upper case 5 and the lower case 6.

The engine 7 is a 4-cycle in-line 4-cylinder engine.
Is driven. The propulsion unit 8 has a propeller shaft 11 connected to the lower end of a drive shaft 9 extending in the vertical direction via a bevel gear mechanism 10, and a propeller 12 at the rear end of the propeller shaft 11.
It is a combination of.

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 the shift operation shaft 62 connected via a link mechanism (not shown) is operated, whereby the shift switching means 63 operates the bevel gear mechanism 10. Control is performed to switch between forward, neutral and reverse shifts.

The engine 7 is arranged on the exhaust guide 13, and the crankshaft 20 is arranged vertically so as to be substantially vertical when traveling, and the lower end of the crankshaft 20 and the upper end of the drive shaft 9 are arranged. Are connected.

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.

The piston 50 reciprocally provided on the cylinder block 21 is connected to the crankshaft 20 via a connecting rod 51, and the reciprocating motion of the piston 50 causes the crankshaft 20 to rotate via the connecting rod 51.

A combustion chamber 52 is formed by the cylinder block 21, the piston 50 and the cylinder head 24, and an ignition plug 53 is formed in the cylinder head 24 so as to face the combustion chamber 52.
Is attached. Further, in the cylinder head 24, the intake passage 45 and the exhaust passage 4 are opened to the combustion chamber 52.
6 is formed.

Cam shafts 26a and 26b of a valve mechanism are axially supported by the cylinder head 24, and the rotational force of the crankshaft 20 is transmitted by a timing belt (not shown). The rotation of the cam shafts 26a and 26b causes the cams 26a1 and 26a1 to rotate. 26b1 drives the intake valve 30 and the exhaust valve 31, and the intake passage 45
And the exhaust passage 46 is opened and closed.

A surge tank 40 is arranged in the engine 7 in the front 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 the cylinder head 2 via an intake pipe 41.
4 is connected to the intake passage 45. Cylinder head 2
An injector 43 is provided in each of the cylinders 4 according to each cylinder.
5 is supplied.

The throttle body 42 is provided with a throttle opening detecting means for detecting the throttle opening, which is composed of an idle speed control valve 420, a throttle 421 and a throttle position sensor S1.
The throttle opening information is sent to the control unit ECU. The control unit ECU uses the idle speed control valve 420.
Control to perform stable idle operation.

The surge tank 40 is provided with a pressure sensor S2 and an intake air temperature sensor S3, and sends intake air pressure information and intake air temperature information to the control unit ECU. The pressure sensor S2 constitutes intake pressure detecting means for detecting intake pressure.

The control unit ECU controls the injector 43 according to the operating state. Fuel is supplied to the injector 43 from the fuel supply device 48. Fuel supply device 48
Is a fuel tank 480, a filter 481, a low pressure pump 4
85, a vapor separator 482, a high pressure pump 483 and a pressure adjusting device 484.

The fuel tank 48 is driven by driving the low pressure pump 485.
Fuel is supplied from 0 to the vapor separator 482 via the filter 481. The high-pressure pump 483 is arranged inside the vapor separator 482, and supplies the pressurized fuel to the injector 43 via the supply pipes 43 a and 43 b when the high-pressure pump 483 is driven.

Excess fuel is passed through the return pipe 43c, the pressure adjusting device 484, and the return pipe 43d to the vapor separator 48.
Returned to 2. The pressure adjusting device 484 is a connecting pipe 484a.
Is connected to the surge tank 40 via the valve and operates with intake pressure to return excess fuel to the vapor separator 482.

Further, the cylinder head 24 is provided with a water temperature sensor S4 and a cam angle sensor S5, and sends the engine water temperature information and the 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 and exhaust. Further, the exhaust passage 46 is provided with an A / F sensor S6 and sends A / F information to the control unit ECU.

The control unit ECU is provided with an engine rotation speed detecting means 49, which calculates the engine rotation speed based on the cam angle information to detect the engine rotation speed. The engine 7 is equipped with an ignition device 55. The ignition device 55 includes a power transistor 550 and an ignition coil 551,
The power transistor 550 is controlled by the control unit ECU.
Is activated to spark the ignition plug 53 through the ignition coil 551 according to the operating state.

The engine control device for a marine vessel propulsion device according to this embodiment is constructed as shown in FIGS. 3 to 6. FIG. 3 shows a schematic configuration diagram of an engine exhaust system, and FIG. 4 shows characteristics of an air-fuel ratio sensor. FIG. 5 is a diagram showing the influence of the output of the air-fuel ratio sensor by the pressure, and FIG. 6 is a diagram showing the influence of the output of the air-fuel ratio sensor by the element temperature.

The exhaust system of the engine 7 of this embodiment is
As shown in FIG. 3, the exhaust passage 46 assembled from each cylinder
Is formed so as to pass through the exhaust guide 13 and the oil pan 90 and communicate with the exhaust expansion chamber 80, so that underwater exhaust is performed.

An air-fuel ratio sensor S6, which is an air-fuel ratio detecting means, is arranged in the exhaust passage 46, and the exhaust temperature sensor S10, which is an exhaust temperature detecting means, is located close to the air-fuel ratio sensor S6.
Are arranged. Further, a detection passage 81 is provided so as to communicate with the exhaust expansion chamber 80 formed in the exhaust passage 46 of the engine 7, and an exhaust pressure sensor S11 as exhaust pressure detection means is arranged in the detection passage 81.

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.

The control unit ECU controls the injector 4 based on the intake pressure, throttle opening and engine speed.
3 controls the fuel injection amount. The control of the fuel injection amount is performed by performing feedback control of the fuel injection amount based on the air-fuel ratio and performing correction based on the exhaust pressure and the exhaust temperature.

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. By the way, this air-fuel ratio sensor S
6, the output of the air-fuel ratio sensor is affected by the pressure, as shown in FIG. The output is set to 100% at the reference pressure, but when the pressure is lower than the reference pressure, for example, the output becomes smaller, so that the fuel injection amount tends to decrease from the reference, and the lean side shifts. Further, for example, if the pressure is higher than the reference pressure, the output becomes large, so that there is a tendency to increase the fuel injection amount from the reference, which shifts to the rich side.

Further, in the air-fuel ratio sensor S6, the output of the air-fuel ratio sensor is influenced by the element temperature, as shown in FIG. The output is set to 100% at the reference element temperature, but when the element temperature is lower than the reference element temperature, for example, the output becomes smaller, so that the fuel injection amount tends to decrease from the reference, and the lean side shifts. Further, for example, when the element temperature is higher than the reference element temperature, the output becomes large, so that there is a tendency to increase the fuel injection amount from the reference, which shifts to the rich side.

As described above, in controlling the fuel injection amount, the fuel injection amount is feedback-controlled based on the air-fuel ratio, and the deviation is corrected based on the exhaust pressure and the exhaust temperature. Therefore, the output of the air-fuel ratio sensor S6 depends on the measured pressure. Even if it is affected, or the output of the air-fuel ratio sensor S6 is affected by the element temperature, more accurate air-fuel ratio control is possible in the entire region and both stable combustion and NOx reduction are achieved. be able to.

Further, by disposing the exhaust pressure sensor S11 in the detection passage 81 so as to communicate with the exhaust expansion chamber 80 formed in the exhaust passage 46 of the engine 7, the exhaust gas expands in the exhaust expansion chamber 80 and the temperature is raised. Exhaust pressure sensor S
The operating temperature of 11 decreases, and the heat resistance required for the exhaust pressure sensor S11 decreases. Also, the exhaust pressure sensor S1
1 can be installed in a place that is unlikely to be submerged in water, improving durability. Further, the exhaust pressure sensor S11 can be installed in a place visible from the outside, which facilitates maintenance and inspection.

Further, by disposing the exhaust temperature sensor S10 close to the air-fuel ratio sensor S6, the exhaust temperature sensor S1
0 can accurately estimate the element temperature of the air-fuel ratio sensor S6,
The air-fuel ratio sensor S6 need not be a high-precision one but may be a standard one, and the cost can be reduced accordingly.

[0046]

As described above, according to the first aspect of the invention, the fuel injection amount is feedback-controlled based on the air-fuel ratio, and the output of the air-fuel ratio detecting means may be influenced by the measured pressure. By performing the correction based on the exhaust pressure, more accurate air-fuel ratio control can be performed in the entire region, and stable combustion and NOx reduction can both be achieved.

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 affected by the element temperature, the correction is performed based on the exhaust temperature. By performing this, more accurate air-fuel ratio control can be performed in all regions, and stable combustion and NOx reduction can both be achieved.

According to the third aspect of the present invention, the fuel injection amount is feedback-controlled based on the air-fuel ratio, and the output of the air-fuel ratio detecting means may be influenced by the measured pressure. Even if the output is affected by the element temperature, by making a correction based on the exhaust pressure and the exhaust temperature, more accurate air-fuel ratio control can be performed in all regions, and stable combustion and NOx reduction can both be achieved. it can.

According to the fourth aspect of the invention, the exhaust pressure is expanded and the temperature is lowered by disposing the exhaust pressure detecting means in the detection passage in communication with the exhaust expansion chamber formed in the exhaust passage of the engine. The heat resistance required for the exhaust pressure detecting means is reduced, and the exhaust pressure detecting means can be installed in a place where it is unlikely to be submerged in water, and the exhaust pressure detecting means can be installed in a place visible from the outside, which facilitates maintenance and inspection.

According to the fifth aspect of the invention, the exhaust gas temperature detecting means is arranged close to the air-fuel ratio detecting means, so that the exhaust temperature detecting means can accurately estimate the element temperature of the air-fuel ratio detecting means.

[Brief description of 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 marine propulsion device.

FIG. 3 is a schematic configuration diagram of an exhaust system of the engine.

FIG. 4 is a diagram showing characteristics of an air-fuel ratio sensor.

FIG. 5 is a diagram showing the effect of pressure on the output of the air-fuel ratio sensor.

FIG. 6 is a diagram showing the influence of the element temperature on the output of the air-fuel ratio sensor.

[Explanation 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 control unit

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 3G084 AA03 BA09 BA13 CA03 CA04                       CA09                 3G301 HA01 HA06 JA21 KA06 LA04                       LB02 LC01 LC03 MA01 MA11                       NA08 NB03 NC02 ND01 NE01                       NE06 PA07Z PA10Z PA11Z                       PD13A PD13Z PD14Z PE01Z                       PE08Z PE10Z

Claims (5)

[Claims] 1. An intake pressure detecting device for detecting an intake pressure, a throttle opening detecting device for detecting a throttle opening, and an engine speed detecting device for detecting an engine speed. And an engine control device for a marine propulsion device that controls a fuel injection amount based on an engine rotation speed, in an exhaust passage of the engine, an air-fuel ratio detecting means for detecting an air-fuel ratio, and an exhaust pressure detecting means for detecting an exhaust pressure. An engine control device for a marine propulsion device, comprising feedback control of the fuel injection amount based on the air-fuel ratio, and correction based on the exhaust pressure. 2. An intake pressure detecting means for detecting an intake pressure, a throttle opening detecting means for detecting a throttle opening, and an engine speed detecting means for detecting an engine speed. And an engine control device for a marine propulsion device that controls a fuel injection amount based on an engine rotation speed, in an exhaust passage of the engine, an air-fuel ratio detecting means for detecting an air-fuel ratio, and an exhaust temperature detecting means for detecting an exhaust temperature. An engine control device for a marine propulsion device, comprising feedback control of the fuel injection amount based on the air-fuel ratio, and correction based on the exhaust temperature. 3. An intake pressure detecting means for detecting an intake pressure, a throttle opening detecting means for detecting a throttle opening, and an engine speed detecting means for detecting an engine speed. And an engine control device for a marine propulsion device that controls a fuel injection amount based on an engine speed, in an exhaust passage of the engine, an air-fuel ratio detecting means for detecting an air-fuel ratio, an exhaust pressure detecting means for detecting an exhaust pressure, An engine for a marine propulsion device, comprising: an exhaust temperature detecting means for detecting an exhaust temperature, feedback controlling the fuel injection amount based on the air-fuel ratio, and performing correction based on the exhaust pressure and the exhaust temperature. Control device. 4. A detection passage is provided in communication with an exhaust expansion chamber formed in an exhaust passage of the engine, and the exhaust pressure detection means is arranged in the detection passage.
Alternatively, the engine control device for the marine vessel propulsion device according to claim 3. 5. The engine control device for a marine vessel propulsion apparatus according to claim 2, wherein the exhaust gas temperature detecting means is arranged in the vicinity of the air-fuel ratio detecting means.