Patent Application
20060271272
The present invention relates to relaying sensor signals, and more particularly to a signal transfer system for relaying an engine position signal.
A vehicle engine includes components that work together to generate drive torque. These components include, but are not limited to, a crankshaft, cylinders, pistons, fuel injectors and sparkplugs. An engine or powertrain control module regulates engine operation based on engine operating parameters including, but not limited to, a rotational position of the crankshaft and a rotational position of a camshaft.
A sensor monitors the crankshaft position and generates a crankshaft position data signal based thereon. Another sensor monitors the camshaft position and generates a camshaft position data signal based thereon. The signals may be used by multiple control modules that regulate vehicle operation. Distribution of the signals to the multiple control modules results in degeneration or weakening of the signals. As a result, noise and other imperfections are generated in the signals, decreasing signal and control accuracy.
Accordingly, the present invention provides a signal transfer system for regulating operation of an internal combustion engine. The signal transfer system includes a shaft that is rotatably driven within an engine. A sensor is responsive to the rotation of the shaft and generates a data signal based on the rotation. A communications bus receives the data signal and generates a replicated data signal based. A first control module receives the replicated data signal and regulates operation of the vehicle based on the replicated data signal.
In one feature, the shaft is a crankshaft and the data signal indicates the rotational position of the crankshaft.
In another feature, the shaft is a camshaft and the signal indicates the rotational position of the camshaft.
In another feature, the communication channel includes a serial data bus.
In another feature, the serial data bus includes a communications bus and a replication module.
In another feature, the replication module generates the replicated data signal.
In still another feature, the first control module processes the replicated data signal and generates a control signal based on the replicate data signal.
In another feature, the replicated data signal is generated by amplifying the data signal.
In another feature, the sensor is responsive to a toothed wheel fixed for rotation with the shaft.
In yet another feature, the communications bus is integrated into the first control module.
In still another feature, the replicated data signal is sent to a second control module.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:
The following description of the preferred embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. For purposes of clarity, the same reference numbers will be used in the drawings to identify similar elements. As used herein, the term module refers to an application specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) and memory that execute one or more software or firmware programs, a combinational logic circuit, and/or other suitable components that provide the described functionality.
Referring now to
The engine 12 includes a crankshaft 18 that is rotatably driven by pistons (not shown). The pistons are driven in cylinders (not shown) during the combustion process. A toothed wheel 20 is fixed for rotation with the crankshaft 18. The wheel 20 includes a plurality of equally spaced teeth 22. However, the wheel 20 also includes an oversized space or gap between a pair of teeth 22. For example, although an exemplary wheel 20 could accommodate 60 equally spaced teeth, the exemplary wheel includes 58 teeth with a gap having a width equal to two teeth therebetween. A rotational position of the gap indicates a rotational position of the crankshaft 18.
A sensor 24 monitors rotation of the wheel 20 and generates a pulse data signal based on the rotational position of the wheel 20. More specifically, as an oncoming edge of a tooth 22 is detected by the sensor 24, the signal goes high and remains high as the tooth 22 passes the sensor 24. As the off-going edge of the tooth 22 is detected by the sensor 24, the signal goes low and remains low until the on-coming edge of an adjacent tooth 22 is detected. The gap provides a point of reference for the sensor 24. More specifically, the position of the crankshaft 18 can be determined based on the extended distance between signal pulses resulting from the gap during the rotation of the wheel 20. The rotational position of the crankshaft 18 can be determined at any point based on the distance between a current pulse and the extended low pulse resulting from passage of the gap.
The engine 12 also includes a camshaft 19 that is rotatably driven by the crankshaft 18. The camshaft 19 regulates opening and closing of intake and exhaust valves (not shown) of the engine 12. A sensor 25 monitors a rotational position of the camshaft 19 based on a toothed wheel (not illustrated) as similarly described above with respect to monitoring the rotational position of the crankshaft 18.
The vehicle 10 also includes first and second control modules 26, 28, respectively. The first control module 26 and the second control module 28 generate control signals to regulate vehicle operation based on the data signal. For example, the first control module 26 can include an engine control module (ECM) that regulates engine operation. The second control module 28 can include a transmission control module (TCM) that regulates operation of the transmission 14. Although two control modules are illustrated, it is appreciated that additional control modules can be implemented that generate control signals based on the data signal.
The vehicle 10 further includes a serial bus 30 that receives the data signal from the sensor 24. The serial bus 30 generates a replicated data signal by amplifying the original data signal. More specifically, the serial bus includes a communications bus 32 and a replication module 34. The replication module 34 amplifies the data signal to increase the current strength of the data signal. The communications bus 32 distributes data signals to the first and second control modules 26,28.
The replicated data signal is distributed to the control modules 26,28 by the serial data bus 30. It is further anticipated that the original signal can be provided to at least one of the control modules 26,28. The serial data bus 30 is electrically isolated to inhibit corruption of the data signal in the event of a short or electrical spike in a connected component. More specifically, the serial data bus 30 includes an electrical ground (not illustrated). Although the serial bus 30 is illustrated as an independent component, it is anticipated that the serial bus 30 can be integrated in one of the control modules (See
Referring now to
The present invention eliminates noise or faults in the original data signal by electrically isolating the data signal and using a serial data bus 30 to amplify and produce a replicated data signal. The serial bus 30 distributes the amplified, replicated data signal to the first and second control modules 26,28. As a result, the control modules 26,28 receive the replicated data signal with a minimal amount of noise and/or error.
Those skilled in the art can now appreciate from the foregoing description that the broad teachings of the present invention can be implemented in a variety of forms. Therefore, while this invention has been described in connection with particular examples thereof, the true scope of the invention should not be so limited since other modifications will become apparent to the skilled practitioner upon a study of the drawings, the specification and the following claims.
