Internal-combustion engines – Charge forming device – Fuel injection system
Reexamination Certificate
1999-12-23
2001-05-08
Miller, Carl S. (Department: 3747)
Internal-combustion engines
Charge forming device
Fuel injection system
C123S494000, C123S456000
Reexamination Certificate
active
06227172
ABSTRACT:
PRIORITY INFORMATION
This application is based on and claims priority to Japanese Patent Application No. Hei 10-370673, filed Dec. 25, 1998, the entire contents of which is hereby expressly incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to an induction system for a multi-cylinder engine. More particularly, the present invention relates to an induction air pressure detection arrangement for an engine of an outboard motor.
2. Description of the Related Art
Outboard motors are used to power marine vehicles. The outboard motors typically include an engine positioned within a protective cowling of the outboard motor. The outboard motor is then attached to the back of the watercraft and used to propel the watercraft in a forward or reversed direction. The outboard motors include induction systems that supply air to a combustion chamber for combustion with fuel supplied by a fuel supply system.
The induction system can include a sensor that approximates the air pressure within a component of the induction system such as an auxiliary passage. The sensor also has been connected to a single component, such as a single intake pipe, of the engine to approximate the air pressure within the system as a whole.
During engine operation, however, air flow through the auxiliary passage increases to a high flow rate. Accordingly, accurately monitoring the pressure within the passage becomes difficult. The rapid passage of air results in often unresolvable errors in the detection system. Accordingly, the sensor can be moved to a different region of the induction system that has a larger diameter and which is closer to the combustion chamber.
A single sensor, therefore, has been positioned proximate a single combustion chamber. The single sensor can more accurately reflect the pressure of the portion of the induction system with which it is associated. The sensor, however, does not reflect the pressure of the balance of the induction system in a very accurate manner. For instance, where the single sensor is associated with the intake pipe of a single cylinder, the sensor may not provide an accurate reading when the particular cylinder is disabled or otherwise malfunctioning. In addition, the single sensor is particularly incapable of reading pressures for each intake pipe just prior to induction of an air charge into each combustion chamber from the associated intake pipe.
SUMMARY OF THE INVENTION
Accordingly, a pressure detection system capable of accurately monitoring a pressure in each induction passage of a multi-cylinder engine is desired. The pressure detection system preferably includes a single sensor that is connected to more than one cylinder. Such a construction enables an accurate pressure comparison between cylinders. In addition, the connecting passages between the sensor and each of the passages preferably are of substantially the same length. In this manner, the phase differences from cylinder to cylinder can be better accommodated. Thus, detection of the pressure changes within the induction system has improved accuracy.
One aspect of the present invention involves an engine comprising a first cylinder and a second cylinder with the first cylinder including a first combustion chamber and the second cylinder including a second combustion chamber. The engine further comprises an induction system that is in fluid communication with the first combustion chamber and the second combustion chamber. The induction system comprises an intake chamber, a first intake conduit that communicates with the intake chamber and the first combustion chamber and a second intake conduit that communicates with the intake chamber and the second combustion chamber. An induction air pressure detection system is operatively connected with the induction system. The detection system comprises an induction air detection pressure sensor. The pressure sensor communicates with the first intake conduit through a first combined conduit path and with the second intake conduit through a second combined conduit path. The first combined conduit path and the second combined conduit path have substantially the same length.
In a preferred mode, the induction system includes a first throttle device that is positioned between the first intake conduit and the intake chamber and a second throttle device that is positioned between the second intake conduit and the intake chamber. The pressure sensor communicates with first intake conduit downstream of the first throttle device with the second intake conduit downstream of the second throttle device.
Another aspect of the present invention involves a multi-cylinder engine comprising multiple cylinders formed within a cylinder block. A set of corresponding multiple cylinders are disposed within the multiple cylinders. A cylinder head is connected to the cylinder block and contains a set of multiple recesses corresponding with the multiple cylinders. Multiple combustion chambers are formed by a corresponding grouping of the pistons, cylinders and cylinder heads. An induction air passage communicates with each of the multiple combustion chambers through corresponding multiple intake pipes. A set of multiple fuel injectors are provided such that each of the multiple intake pipes has at least one of the set of multiple fuel injectors associated therewith. The fuel injectors inject fuel to form a fuel/air charge in the combustion chambers. A fuel rail supplies fuel to the fuel injectors and is connected to a pressure regulator. A pressure sensor is placed in communication with two or more of the multiple intake pipes through a multi-part induction air pressure pipe. A length of the multi-part induction air pressure pipe between the pressure sensor and each of the two or more of the multiple intake pipes is substantially the same.
In a preferred mode, each of the multiple intake pipes includes a throttle device that controls a flow of air through the corresponding intake pipe. The pressure sensor communicates with the multiple intake pipes through the air pressure pipe at a location downstream from the throttle devices.
These and other features, aspects and advantages of the present invention will become apparent from the detailed description of a preferred embodiment that follows.
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Katayama Goichi
Nakayasu Yoshikazu
Knobbe Martens Olson & Bear LLP
Miller Carl S.
Sanshin Kogyo Kabushiki Kaisha
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