Misfiring sensing apparatus for an internal combustion engine

A misfiring sensing apparatus for an internal combustion engine comprising:

• ionic current sensing means for sensing an ionic current generated upon combustion of fuel in said engine and generating a corresponding output signal;
• ionic current determining means for determining whether an ionic current is present in each ignition cycle of each cylinder based on the output of said ionic current sensing means and generating a corresponding output signal;
• misfiring determining means for determining misfiring in said engine based on the output of said ionic current determining means;
• break sensing means for determining a break of wiring in said ionic current sensing means;
• and
• failure determining means for determining a failure in said ionic current sensing means based on the output of said break sensing means.

A misfiring sensing apparatus for an internal combustion engine comprising:

• ionic current sensing means for sensing an ionic current generated upon combustion of fuel in said engine and generating a corresponding output signal;
• operating range sensing means for sensing an operating range of said engine;
• ionic current determining means for determining whether an ionic current is present in each ignition cycle of each cylinder of said engine based on the output of said ionic current sensing means and generating a corresponding output signal;
• misfiring determining means for determining misfiring in said engine based on the output of said ionic current determining means;
• cylinder identifying means for identifying each cylinder;
• misfiring cylinder identifying means for identifying a misfiring cylinder based on the outputs of said misfiring determining means and said cylinder identifying means;
• and
• misfiring determination inhibiting means for inhibiting misfiring determination in a special operating range of said engine in which it is difficult to sense an ionic current.

A misfiring sensing apparatus for an internal combustion engine comprising:

• ionic current sensing means for sensing an ionic current generated upon combustion of fuel in said engine and generating a corresponding output signal;
• ionic current determining means for determining whether an ionic current is present in each ignition cycle of each cylinder of said engine based on the output signal of said ionic current sensing means and generating a corresponding output signal;
• misfiring determining means for determining misfiring in said engine based on the output signal of said ion current determining means;
• cylinder identifying means for identifying each cylinder based on a signal related to the ignition of a specific cylinder of said engine;
• and
• misfiring cylinder identifying means for identifying a misfiring cylinder based on the outputs of said misfiring determining means and said cylinder identifying means.

A misfiring sensing apparatus for an internal combustion engine comprising:

• signal forming means connected to a plurality of spark plugs of cylinders of said engine for forming ionic current signals from said spark plugs into a single signal;
• single ionic current sensing means connected through a secondary winding of an ignition coil to said signal forming means for sensing an ionic current generated upon combustion of fuel in each cylinder and generating a corresponding output signal for each cylinder;
• ionic current determining means for determining whether an ionic current is present in each ignition cycle of each cylinder of said engine based on the output signal of said ionic current sensing means and generating a corresponding output signal;
• misfiring determining means for determining misfiring in each cylinder based on the output signal of said ionic current determining means;
• a crank angle sensor for generating a cylinder identifying signal and a reference position signal indicative of predetermined reference crank positions of each cylinder;
• cylinder identifying means for identifying each cylinder based on the cylinder identifying signal from said crank angle sensor;
• and
• misfiring cylinder identifying means for identifying a misfiring cylinder based on the outputs of said misfiring determining means and said cylinder identifying means.

A misfiring sensing apparatus for an internal combustion engine comprising:

• a plurality of ionic current sensing means each connected to a spark plug of a corresponding cylinder of said engine through a secondary winding of an ignition coil for sensing an ionic current generated upon combustion of fuel in the corresponding cylinder and generating a corresponding output signal for each cylinder;
• signal forming means connected to said plurality of ionic current sensing means for forming the output signals from said plurality of ionic current sensing means into a single signal;
• ionic current determining means for determining whether an ionic current is present in each ignition cycle of each cylinder based on the single output signal from said signal forming means and generating a corresponding output signal;
• misfiring determining means for determining misfiring in each cylinder based on the output signal of said ionic current determining means;
• a crank angle sensor for generating a reference position signal indicative of predetermined crank positions of each cylinder;
• cylinder identifying means for identifying each cylinder based on at least one output signal from said ionic current sensing means;
• and
• misfiring cylinder identifying means for identifying a misfiring cylinder based on the outputs of said misfiring determining means and said cylinder identifying means.

A misfiring sensing apparatus for an internal combustion engine comprising:

• ionic current sensing means for sensing an ionic current generated upon combustion of fuel in said engine and generating a corresponding output signal;
• ionic current determining means for determining whether an ion current is present in each ignition cycle of each cylinder based on the output signal of said ionic current sensing means and generating a corresponding output signal;
• misfiring determining means for determining misfiring in said engine based on the output of said ionic current sensing means;
• cylinder identifying means for identifying each cylinder;
• and
• misfiring cylinder identifying means for identifying a misfiring cylinder based on the outputs of said misfiring determining means and said cylinder identifying means;
• wherein said ionic current determining means is provided outside of said misfiring determining means, the output signal from said ionic current determining means being fetched into said misfiring determining means at every predetermined crank angle to perform misfiring determination.