Engine control system
First Claim
1. An internal combustion engine comprising a cylinder body defining at least one cylinder bore in which a piston reciprocates to rotate a crankshaft, a cylinder head affixed to an end of the cylinder body and defining a combustion chamber with the cylinder bore and the piston, an air induction system arranged to introduce air to the combustion chamber, the air induction system including a main passage, a throttle valve movable within the main passage between an open position and a closed position to regulate air flow through the main passage, an idle passage bypassing the throttle valve, and an idle valve movable within the idle passage between an open position and a closed position to regulate air flow through the idle passage, a fuel supply system arranged to supply fuel to the combustion chamber, an ignition system arranged to fire an air/fuel charge within the combustion chamber, a throttle valve position sensor arranged to sense that the throttle valve is generally placed in the closed position, an engine speed sensor arranged to sense a rotational speed of the crankshaft, and a control device connected with the sensors, the idle valve and the ignition system, the control device being configured to practice one of slow down controls comprising bringing the idle valve to the closed position, retarding ignitions by the ignition system and thinning out a certain number of ignitions by the ignition system to slow down the rotational speed of the crankshaft based upon a throttle position signal from the throttle valve position sensor and an engine speed signal from the engine speed sensor when the throttle position signal indicates that the throttle valve is generally placed in the closed position and the speed signal indicates that the rotational speed of the crankshaft exceeds a preset speed, and the control device being further configured to practice one of the remaining slow down controls when the speed signal still indicates that the rotational speed of the crankshaft exceeds the preset speed.
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Accused Products
Abstract
An engine control system includes an improved construction that can release an engine from an abnormal engine speed so that, for example, the operator can operate a shift actuator without any overload. The engine includes an air induction system that introduces air to the combustion chamber and includes a throttle valve. The throttle valve admits the air to flow through the air induction system unless placed in a closed position. A throttle valve position sensor is arranged to sense the position of the throttle valve. An engine speed sensor is also arranged to sense a rotational speed of the crankshaft. A control device is provided for slowing down the engine speed based upon a throttle position signal from the throttle valve position sensor and a speed signal from the engine speed sensor. In one operating mode, the slow down control is made when the throttle position signal indicates that the throttle valve is generally at the closed position and the speed signal indicates that the engine speed exceeds a preset speed.
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Citations
38 Claims
- 1. An internal combustion engine comprising a cylinder body defining at least one cylinder bore in which a piston reciprocates to rotate a crankshaft, a cylinder head affixed to an end of the cylinder body and defining a combustion chamber with the cylinder bore and the piston, an air induction system arranged to introduce air to the combustion chamber, the air induction system including a main passage, a throttle valve movable within the main passage between an open position and a closed position to regulate air flow through the main passage, an idle passage bypassing the throttle valve, and an idle valve movable within the idle passage between an open position and a closed position to regulate air flow through the idle passage, a fuel supply system arranged to supply fuel to the combustion chamber, an ignition system arranged to fire an air/fuel charge within the combustion chamber, a throttle valve position sensor arranged to sense that the throttle valve is generally placed in the closed position, an engine speed sensor arranged to sense a rotational speed of the crankshaft, and a control device connected with the sensors, the idle valve and the ignition system, the control device being configured to practice one of slow down controls comprising bringing the idle valve to the closed position, retarding ignitions by the ignition system and thinning out a certain number of ignitions by the ignition system to slow down the rotational speed of the crankshaft based upon a throttle position signal from the throttle valve position sensor and an engine speed signal from the engine speed sensor when the throttle position signal indicates that the throttle valve is generally placed in the closed position and the speed signal indicates that the rotational speed of the crankshaft exceeds a preset speed, and the control device being further configured to practice one of the remaining slow down controls when the speed signal still indicates that the rotational speed of the crankshaft exceeds the preset speed.
- 6. A marine propulsion unit comprising an internal combustion engine, a transmission device, a propulsion device for propelling the propulsion unit, the transmission device being arranged to transmit engine power from the engine to the propulsion device, a shift mechanism arranged to shift the transmission device among the forward, neutral and reverse positions, a shift position sensor arranged to sense that the transmission device is in either the forward position or the reverse position, the internal combustion engine including a cylinder body defining at least one cylinder bore in which a piston reciprocates to rotate a crankshaft, which is coupled to the transmission, a cylinder head affixed to an end of the cylinder body and defining a combustion chamber with the cylinder bore and the piston, an air induction system arranged to introduce air to the combustion chamber, the air induction system including a throttle valve movable between an open position and a closed position to regulate air flow through the air induction system, a throttle valve position sensor arranged to sense that the throttle valve is generally placed in the closed position, an engine speed sensor arranged to sense a rotational speed of the crankshaft, and a control device including a timer that counts a preset time, the control device being configured to practice a slow down control to slow down the rotational speed of the crankshaft based upon a shift position signal from the shift position sensor, a throttle position signal from the throttle valve position sensor and a speed signal from the engine speed sensor when the shift position signal indicates that the propulsion device is in either the forward position or the reverse position, the throttle position signal indicates that the throttle valve is generally in the closed position and the speed signal indicates that the engine speed exceeds a preset speed, and the control device being further configured to suspend the slowdown control for the preset time after determining that the throttle valve is generally placed in the closed position.
- 7. A method of controlling an internal combustion engine having a crankshaft and an air induction system including a throttle valve, comprising sensing a position of the throttle valve, sensing a rotational speed of the crankshaft, and attempting to slow down the rotational speed of the crankshaft if the throttle valve is generally placed at a closed position and the rotational speed exceeds a preset speed, further sensing the rotational speed of the crankshaft, and further attempting to slow down the rotational speed of the crankshaft if the rotational speed of the crankshaft still exceeds the preset speed at the further sensing.
- 8. A method of controlling an internal combustion engine for a marine propulsion unit, the marine propulsion unit including a transmission device and a shift mechanism arranged to shift the transmission device among the forward, reverse and neutral positions, the engine including a crankshaft and an air induction system having a throttle valve, the method comprising sensing a position of the transmission device, determining whether the transmission device is in either the forward position or the reverse position, sensing a position of the throttle valve, determining whether the throttle valve is generally placed in a closed position, counting a preset time if the throttle valve is generally placed in the closed position to suspend proceeding further for the preset time, sensing a rotational speed of the crankshaft, determining whether the rotational speed of the crankshaft exceeds a preset speed, and slowing down the rotational speed of the crankshaft if the transmission device is in either the forward position or the reverse position, the throttle valve is generally placed in a closed position and the rotational speed exceeds the preset speed.
- 9. An internal combustion engine comprising a cylinder body defining a plurality of cylinder bores in which pistons reciprocates to rotate a crankshaft, a cylinder head affixed to an end of the cylinder body and defining a plurality of combustion chambers with the cylinder bores and the pistons, an air induction system arranged to introduce air to the combustion chambers, the air induction system including a main passage, at least one throttle valve movable between an open position and a closed position to regulate air flow through the main passage, an idle passage bypassing the throttle valve, and an idle valve movable within the idle passage between an open position and a closed position to regulate air flow through the idle passage, a fuel supply system arranged to supply fuel to the combustion chambers, an ignition system arranged to fire air/fuel charges within the combustion chambers, a throttle valve position sensor arranged to sense that the throttle valve is generally placed in the closed position, an engine speed sensor arranged to sense a rotational speed of the crankshaft, and a control device connected with the sensors, the idle valve and the ignition system, the control device being configured to practice one of slow down controls comprising bringing the idle valve to the closed position, retarding a firing timing of the ignition system and disabling the ignition system from firing some of the combustion chambers to slow down the rotational speed of the crankshaft based upon a throttle position signal from the throttle valve position sensor and an engine speed signal from the engine speed sensor when the throttle position signal indicates that the throttle valve is generally placed in the closed position and the speed signal indicates that the rotational speed of the crankshaft exceeds a preset speed, and the control device being further configured to practice one of the remaining slow down controls when the speed signal still indicates that the rotational speed of the crankshaft exceeds the preset speed.
- 10. An internal combustion engine comprising a cylinder body defining at least one cylinder bore in which a piston reciprocates to rotate a crankshaft, a cylinder head affixed to an end of the cylinder body and defining a combustion chamber with the cylinder bore and the piston, an air induction system arranged to introduce air to the combustion chamber, the air induction system including a throttle valve movable between an open position and a closed position to regulate air flow through the air induction system, a throttle valve position sensor arranged to sense that the throttle valve is generally placed at the closed position, an engine speed sensor arranged to sense a rotational speed of the crankshaft, and a control device connected at least to the sensors, the control device being configured to practice a first slow down control to slow down the rotational speed of the crankshaft based upon a throttle position signal from the throttle valve position sensor and an engine speed signal from the engine speed sensor when the throttle position signal indicates that the throttle valve is generally placed in the closed position and the speed signal indicates that the rotational speed of the crankshaft exceeds a preset speed, the control device being further configured to determine whether the rotation speed of the crankshaft still exceeds the preset speed after practicing the first slow down control, and the control device being still further configured to practice a second slow down control when determining that the rotational speed of the crankshaft still exceeds the preset speed.
Specification