Opinion ID: 773385
Heading Depth: 3
Heading Rank: 2

Heading: Detailed Discussion

Text: 9 The '348 patent describes the breaker, electronic, and magneto ignition systems in detail in lines 5 through 56 of column 5. The patent describes how, in each of these ignition systems, low voltage timing pulses are provided by various sensing devices. For breaker and electronic ignition systems, the sensing devices include mechanical points, solid-state devices, or Hall effect devices. Mechanical points are typically driven by a camshaft, which in turn is driven by the engine's crankshaft. As the camshaft rotates, it forces the points apart. When the points are separated, the ignition coil temporarily loses its ground (i.e., the points temporarily break the low voltage current being fed to the ignition coil) and generates a high voltage pulse that fires the spark plugs. Thus, spark plug firing is caused by, and therefore can be determined by, the low voltage interrupt generated by the points as the camshaft rotates. This low voltage interrupt is input to the control unit of the present invention. 10 A Hall effect device tracks camshaft position using a metallic timing cup having a pair of windows cut into the cup's sides. See '348 patent, at col. 5, ll. 37-39. The metallic timing cup is typically attached to a camshaft, id., which is driven by the engine's crankshaft assembly. The position of the windows on the metallic timing cup corresponds to the position of the pistons within the two cylinders, respectively. See id. at col. 5, ll. 39-41. That is, each window corresponds to a plug firing and causes a magnetic field that creates a low voltage pulse that is sent to the ignition coil, id., to cause the ignition coil to send a high voltage pulse to fire the spark plugs. Thus, spark plug firing is caused by, and therefore can be determined by, a Hall effect device's tracking of windows on a metallic timing cup. The low voltage pulse created by the Hall effect device is input to the control unit of the present invention. Id. at col. 5, ll. 43-45. 11 Magneto ignition systems are described as using a rotating magnet to generate a constantly changing flux in the core winding of a magneto coil. In the same manner as in the breaker or electronic systems, interruption of the control coil current in the magneto system causes high voltage signals to be generated to fire the spark plugs. Thus, spark plug firing is caused by, and therefore can be determined by, the low voltage interrupt caused by the changing flux. This low voltage interrupt is input to the control unit of the present invention. 12 The patented system describes the output of the electronic ignition system sensor (e.g., mechanical points, solid-state devices, Hall effect devices) as directly feeding the control unit. Id. at col. 5, ll. 43-45. If the ignition system uses mechanical points or a Hall effect device, the output of these sensors is described as being used to feed the control unit. Id. at col 5, ll. 45-48. Similarly, the interruption of the control coil current in the magneto system is described as being used to feed the control unit. Id. at col. 5, ll. 50-51. Thus, the '348 patent describes the electronic sensors which are present in the three conventionally used V-twin motorcycle engine ignition systems and the manner in which those sensors determine when, in the engine timing cycle, the ignition system of the engine delivers a low voltage pulse to fire the spark plugs. 13 The written description of the '348 patent goes on to describe how the control unit analyzes the low voltage timing pulses generated by the electronic sensing devices to determine which cylinder should be charged with fuel. It does this by measuring the time span between successive pulses. The relationship of spark plug firing between cylinders is fixed for any given type of internal combustion engine based on its structural configuration. In a V-twin engine, the period between spark plug firing between the first cylinder (cylinder 1) and the second cylinder (cylinder 2) is asymmetrical due to the V-shape formed by (or the angle between) the cylinders. Id. at col. 5, l. 57-col. 6, l. 3. In a Harley-Davidson V-twin engine utilizing a Hall effect device, the windows on the camshaft's metallic timing cup reflect this asymmetry. That is, the distance, in one direction, between the window representing cylinder 1 and the window representing cylinder 2 is 4/9 of the circumference of the timing cup in a typical Harley-Davidson engine. The distance, moving in the same direction, between the window representing cylinder 2 and the window representing cylinder 1 is 5/9 of the circumference of the timing cup. 14 By measuring the asymmetrical firing of the spark plugs, the conversion system of the '348 patent electronically determines which cylinder should be injected with fuel. An engine timer in the control unit measures the time duration between spark plug firings, i.e., the time between electronic signals received from the electronic ignition system sensor. The control unit stores the times for comparison to determine the longer and shorter periods. By comparing the differences, the desired sequence of cylinder charging is determined by the control unit. The varying distance between the cup windows can be translated into the time lapse between the spark plug firing from cylinder 1 to cylinder 2, which is different than the time lapse between the spark plug firing from cylinder 2 to cylinder 1. For example, when the control unit detects a 4/9 spacing (or time gap) between the windows, cylinder 1 is to be injected with fuel. Conversely, when the Hall effect device detects a 5/9 spacing (or time gap) between the windows, cylinder 2 is to be injected with fuel. Id. at col. 6, ll. 4-10. 15 The '348 patent's fuel injection system uses a number of other sensors to detect various system parameters and supply further input signals to the control unit. See id. at col. 2, ll. 4-19. The control unit integrates (or processes) the input signals, and transmits output signals to the fuel injectors causing each fuel injector to charge its associated cylinder with fuel at the proper time. 1 See id. at col. 3, l. 65 col. 4, l. 3.