Engine combustion control with ignition timing by pressure ratio management

An ignition timing control for an internal combustion engine of the type having a combustion chamber, a rotating crankshaft and ignition apparatus for the combustion chamber comprising, in combination:

• a pressure sensor responsive to combustion chamber pressure to generate an output voltage, the pressure sensor being linear with a gain and bias which do not significantly vary during a single engine cycle;
• means effective to sample the output voltage of the pressure sensor at first and second predetermined crankshaft rotational angles in the compression stroke prior to combustion, at a third predetermined crankshaft rotational angle during combustion and at a fourth predetermined crankshaft rotational angle at substantially complete combustion, the first and fourth predetermined crankshaft angles having identical combustion chamber volumes;
• means effective to derive, from the sensor voltage outputs at the first, second, third and fourth predetermined crankshaft rotational angles, the ratio of first and second pressure ratios, the first and second pressure ratios being the ratios of combustion pressure indicated by the pressure sensor to motored pressure at the third and fourth predetermined crankshaft rotational angles, respective1y;
• and
• means responsive to the last means to adjust the ignition timing to maintain a predetermined ratio between the first and second pressure ratios each decreased by one, whereby combustion timing is controlled in closed loop to an MBT value.

A combustion control for an internal combustion engine of the type having a combustion chamber, a rotating crankshaft, ignition apparatus for the combustion chamber and diluent gas f1ow control apparatus comprising, in combination:

• means responsive to combustion chamber pressure to generate signals for a combustion event indicating combustion pressure and motored pressure at a first predetermined crankshaft rotational angle during combustion and at a second predetermined crankshaft rotational angle at substantially complete combustion;
• means effective to compute, from the signals, first and second pressure ratios of combustion pressure to motored pressure at the first and second crankshaft rotational angles, respectively;
• means responsive to the last means to adjust the ignition timing to maintain a predetermined ratio between the first and second pressure ratios each decreased by one;
• and
• means effective to adjust the diluent gas flow to maintain the second pressure ratio at a predetermined value, whereby combustion timing and diluent flow are controlled optimally in closed loop.

A combustion control for an internal combustion engine of the type having a combustion chamber, a rotating crankshaft, ignition apparatus for the combustion chamber and diluent gas flow control apparatus comprising, in combination:

• means responsive to combustion chamber pressure to generate signals for a combustion event indicating combustion pressure and motored pressure at a first predetermined crankshaft rotational angle during combustion, a second predetermined crankshaft rotational ang1e at substantially complete combustion and a third predetermined crankshaft rotational angle during combustion;
• means effective to compute, from the signals, first, second and third pressure ratios of combustion pressure to motored pressure at the first, second and third crankshaft rotational angles, respectively;
• means responsive to the last means to adjust the ignition timing to maintain a predetermined ratio between the first and second pressure ratios each decreased by one;
• and
• means effective to adjust diluent gas flow to maintain a predetermined ratio between the second and third pressure ratios each decreased by one, whereby combustion timing and diluent flow are controlled optimally in closed loop.

A combustion control for an internal combustion engine of the type having a combustion chamber, a rotating crankshaft, ignition apparatus for the combustion chamber and diluent gas flow control apparatus comprising, in combination:

• means responsive to combustion chamber pressure to generate signals for a combustion event indicating combustion pressure and motored pressure at a first predetermined crankshaft rotational angle during combustion and a second predetermined crankshaft rotational angle at substantially complete combustion;
• means effective to compute, from the signals, first and second pressure ratios of combustion pressure to motored pressure at the first and second crankshaft rotational angles, respectively;
• means responsive to the last means to adjust the ignition timing to maintain a predetermined ratio between the first and second pressure ratios each decreased by one;
• and
• means effective to maintain an average of consecutive ratios of the first and second pressure ratios each decreased by one and adjust diluent gas flow in response to the degree of variation of individual ones of the consecutive ratios from the average, whereby combustion timing and diluent flow are controlled optimally in closed loop.

A combustion control for an internal combustion engine of the type having a plurality of combustion chambers, air supply apparatus for the combustion chambers, fuel supply apparatus having individual control for each combustion chamber, a rotating crankshaft and ignition apparatus for the combustion chambers comprising, in combination:

• means responsive to the pressure in each combustion chamber to generate signals for a combustion event indicating combustion pressure and motored pressure at a first predetermined crankshaft rotationa1 angle during combustion and a second predetermined crankshaft rotational angle at substantially complete combustion;
• means effective to compute, from the signals, first and second pressure ratios of combustion pressure to motored pressure at the first and second crankshaft rotational angles, respectively;
• means to adjust the ignition timing to maintain a predetermined ratio between the first and second pressure ratios each decreased by one;
• and
• means effective to derive from values of the second pressure ratio an average second pressure ratio for all combustion chambers and adjust the fuel supplied to each combustion chamber in accordance with the average second pressure ratio divided by the second pressure ratio for that combustion chamber to even fuel distribution among the combustion chambers, whereby the ignition timing is controlled to MBT and the fuel flow is optimized for lean burn operation.