Electricity: measuring and testing – Electrical speed measuring – Including speed analog electrical signal generator
Reexamination Certificate
2003-02-27
2004-08-31
LeDynh, Bot (Department: 2862)
Electricity: measuring and testing
Electrical speed measuring
Including speed analog electrical signal generator
C123S04100E, C123S617000, C073S510000
Reexamination Certificate
active
06784658
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a rotation information detector for detecting rotation information including information on a rotational direction of an internal combustion engine, and a signal generator used in the detector.
BACKGROUND OF THE INVENTION
In many vehicles such as scooters, snowmobiles, or buggies that value simplicity of use, a two cycle internal combustion engine is frequently used as a driving source. Such vehicles often use a variable speed type transmission of a centrifugal clutch type, which does not have a back-up gear, as a transmission provided between a crankshaft of the engine and a driving wheel. However, even a vehicle that uses such a simple transmission is desirably backed using an engine when a body is heavy or a snowmobile having crashed into snow is backed.
Thus, it has been supposed that when a two cycle internal combustion engine is used as a driving source, a feature of the two cycle internal combustion engine that allows rotation in both forward and reverse directions is used to allow reversal of a rotational direction of the engine in accordance with a driver's instruction, thereby permitting the engine to be driven in both forward and reverse rotation states.
A known method for reversing a rotational direction of a two cycle internal combustion engine is such that in accordance with a driver's reversal instruction, a rotational speed of the engine is lowered to a set rotational speed below an idling speed by fuel cut, engine misfire, or ignition timing delay, the ignition timing is then excessively advanced to reverse the rotational direction of the engine, and after the reversal of the rotational direction of the engine is confirmed, the ignition timing of the engine is shifted to timing suitable for keeping driving of the engine with the rotational direction reversed.
For reversing the rotational direction of the internal combustion engine by such a method to drive the engine in the forward and the reverse rotation states, obtaining information on the rotational direction of the engine is essential.
An internal combustion engine built in a vehicle using a transmission with a gear for backing up sometimes requires obtaining information on the rotational direction of the engine in order to prevent the reverse rotation of the engine.
When the ignition timing of the internal combustion engine is controlled by a microprocessor, a predetermined rotational angle position (crank angle position) of a crankshaft of the engine is set as a reference position, the ignition timing is arithmetically operated relative to timing at which the rotational angle position of the crankshaft corresponds to the reference position, and measuring the arithmetically operated ignition timing is started when the rotational angle position of the crankshaft corresponds to the reference position. Thus, in this case, it is necessary to be able to detect that the rotational angle position of the crankshaft corresponds to the reference position.
Further, when the engine runs at extremely low speed, the rotational speed of the crankshaft varies minutely due to changes in strokes of the engine, and precise measurement of the ignition timing arithmetically operated by the microprocessor is difficult. Thus, when the engine runs at extremely low speed, it is preferable that the ignition is not performed at the ignition timing arithmetically operated by the microprocessor, but is performed at predetermined fixed ignition timing. In the case where the ignition is performed at the fixed ignition timing when the engine runs at extremely low speed (when the rotational angle position of the crankshaft corresponds to a fixed ignition position), it is necessary to be able to detect that the rotational angle position of the crankshaft corresponds to a position corresponding to the ignition timing when the engine runs at extremely low speed.
When the ignition timing is controlled by the microprocessor, the rotational speed of the engine is calculated by measuring time for the crankshaft to rotate by a fixed angle.
In order to obtain various rotation information such as the information on the rotational direction of the internal combustion engine, the information on the reference position of the crankshaft, the information on the ignition position when the engine runs at extremely low speed, or the information on the rotational speed, a signal generator is widely used that comprises a rotor in the form of an inductor having a reluctor and provided to rotate in synchronization with the engine, and a sensor that detects a leading edge and a trailing edge in a rotational direction of the reluctor of the rotor to generate a leading edge detection pulse and a trailing edge detection pulse having different polarities.
A known method for obtaining information on a rotational direction of an engine using such a signal generator is disclosed in U.S. Pat. No. 5,794,574. In the prior art, two sensors are placed at a predetermined interval around a rotor in the form of an inductor having two reluctors, and information on whether the engine rotates forward or reversely is obtained using a feature that a relationship between a length of a time period between when one of the sensors detects a trailing edge of one reluctor of the rotor to generate a trailing edge detection pulse and when the other sensor detects a leading edge of one reluctor to generate a leading edge detection pulse, and a length of a time period when the other sensor detects a trailing edge of the other reluctor to generate a trailing edge detection pulse and when one sensor detects the leading edge of one reluctor to generate the leading edge detection pulse differs in forward rotation and in reverse rotation of the engine.
When the rotational speed of the crankshaft of the internal combustion engine is constant, as the method disclosed in the above U.S. Patent, comparing generation intervals of particular pulses allows the rotational speed of the engine to be reliably discriminated. However, when the engine runs at extremely low speed, the rotational speed of the crankshaft varies during one rotation of the crankshaft due to changes in strokes of the engine, thus the above described method may cause erroneous discrimination of the rotational direction.
For a multi-cylinder internal combustion engine having two or more cylinders, provided on a rotor side with a reluctor corresponding to each cylinder of the engine, it is necessary to obtain information (cylinder discrimination information) for discriminating which cylinder a series of pulses, generated by a sensor detecting a leading edge and a trailing edge of a series of reluctors, corresponds to, but the signal generator disclosed in the above U.S. patent cannot provide such cylinder discrimination information.
SUMMARY OF THE INVENTION
Therefore, an object of the invention is to provide a signal generator for an internal combustion engine capable of generating a signal for obtaining precise rotation information including information on a rotational direction of an engine and cylinder discrimination information even when the engine runs at extremely low speed at which a rotational speed of a crankshaft widely varies.
Another object of the invention is to provide a rotation information detector for an internal combustion engine that uses the above described signal generator to obtain rotation information including information on a rotational direction of an engine and cylinder discrimination information.
The invention provides a signal generator used for detecting rotation information including information on a rotational direction of a multi-cylinder internal combustion engine having two or more cylinders and cylinder discrimination information, and a rotation information detector using the signal generator.
The signal generator according to the invention comprises: a rotor in the form of an inductor having a first series of reluctors as many as cylinders of the internal combustion engine, that are provided correspondingly to each cylind
Arakawa Yoshinobu
Kawagoe Jun
Sasaki Kouji
Tsukada Yoshikazu
Kokusan Denki Co. Ltd.
LeDynh Bot
Pearne & Gordon LLP
LandOfFree
Signal generator for multi-cylinder internal combustion... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Signal generator for multi-cylinder internal combustion..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Signal generator for multi-cylinder internal combustion... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3291619