Motorcycle having system for combustion knock control

A motorcycle comprising:

• a frame;
• front and rear wheels coupled to the frame for rotation with respect to the frame;
• a two-cylinder, air-cooled, V-twin engine mounted to the frame, the engine including a housing, a crankshaft mounted for rotation within the housing, first and second cylinders having first and second combustion chambers, respectively, and first and second pistons reciprocating in the first and second cylinders, respectively;
• a spark generating circuit including a spark plug having a spark gap exposed to the first combustion chamber, the spark generating circuit produces a spark across the spark gap in response to a sparking signal;
• an ion signal circuit that generates an ion signal indicative of an ion current being generated across the spark gap;
• a conditioning chip that receives the ion signal and generates a knock intensity signal;
• and
• a processor and software for operating the processor to provide the sparking signal at a timed sequence, to determine whether the knock intensity signal represents knock, and to modify the timed sequence in response to an indication of knock in the first cylinder.

A method of controlling knock in a two-cylinder air-cooled V-twin engine of a motorcycle, the method comprising the acts of:

• providing a motorcycle including
• a frame,
• front and rear wheels coupled to the frame for rotation with respect to the frame,
• a two-cylinder, air-cooled, V-twin engine mounted to the frame, the engine including a housing, a crankshaft mounted for rotation within the housing, first and second cylinders having first and second combustion chambers, respectively, and first and second pistons reciprocating in the first and second cylinders, respectively, and
• a spark generating circuit including a spark plug having a spark gap exposed to the first combustion chamber;
• generating a first spark in the first combustion chamber with the first spark plug when the first piston is in a first position;
• obtaining an ion signal indicative of an ion current across the first spark plug gap;
• determining if the ion signal indicates knock within the first cylinder;
• and
• generating a second spark in the first combustion chamber with the first spark plug when the piston is in a second position and in response to an indication of knock in the first cylinder, whereby the second position is different than the first position.

A method of varying a spark event in a two-cylinder, air-cooled, V-twin engine of a motorcycle, the method comprising the acts of:

• providing a motorcycle comprising
• a frame,
• front and rear wheels coupled to the frame for rotation with respect to the frame,
• a two-cylinder, air-cooled, V-twin engine mounted to the frame, the engine including a housing, a crankshaft mounted for rotation within the housing, first and second cylinders having first and second combustion chambers, respectively, and first and second pistons reciprocating in the first and second cylinders, respectively
• a first spark generating circuit including a first spark plug having a first spark gap exposed to the first combustion chamber, and
• a second spark generating circuit including a second spark plug having a second spark gap exposed to the second combustion chamber;
• generating a first spark in the first combustion chamber with the spark plug when the piston is in a first position;
• obtaining a first ion signal indicative of an ion current in the first spark plug gap;
• determining if knock is present within the first cylinder, the determining act comprising the acts of
• applying the first ion signal to a low-pass filter to produce a first low-pass signal,
• applying the first low-pass signal to a band-pass filter having a knock window to produce a first band-pass signal,
• applying the first band-pass signal to an integrator to produce a first integrated signal having a first energy value representing an amount of energy within the first band-pass signal,
• providing a threshold value, and
• determining if the first energy value is greater than the threshold value;
• generating a second spark in the first combustion chamber with the first spark plug when the piston is in a second position and in response to the energy value being greater than the threshold value, whereby the second position is different than the first position;
• repeatedly obtaining positions of the second piston;
• generating a third spark in the second combustion chamber with the second spark plug when the second piston is in a third position;
• obtaining a second ion signal that is indicative of an ion current in the second spark gap;
• determining if knock is present within the second cylinder, the determining act including the acts of
• applying the second ion signal to the low-pass filter to produce a second low-pass signal,
• applying the low-pass signal to the band-pass filter to produce a second band-pass signal,
• applying the second band-pass signal to the integrator to produce a second integrated signal having a second energy value representing an amount of energy within the second band-pass signal, and
• determining if the second energy value is greater than the threshold value;
• and
• generating a fourth spark in the second combustion chamber with the second spark plug when the piston is in a fourth position and when the second energy value being greater than the threshold value, whereby the fourth position is different than the third position.