Engine air/fuel ratio controller

Claim 1

A system for controlling the air/fuel ratio of the air and fuel mixture supplied to an internal combustion engine of a vehicle having an automatic transmission selectively operable between neutral and drive conditions, the system comprising: means for sensing the temperature of the engine; means for providing a first schedule of air/fuel ratios as a function of engine temperature, the first schedule of air/fuel ratios representing the desired temperature dependent air/fuel ratio of the mixture supplied to the engine when the transmission is in the drive condition; means for providing a second schedule of air/fuel ratios as a function of engine temperature, the second schedule of air/fuel ratios representing the desired temperature dependent air/fuel ratios of the mixture supplied to the engine when the transmission is in the neutral condition; means for sensing the neutral or drive condition of the transmission; means for establishing the air/fuel ratio of the engine in accord with the first schedule of air/fuel ratios during a sensed drive condition of the transmission; and means for establishing the air/fuel ratio of the engine in accord with the second schedule of air/fuel ratios during a sensed neutral condition of the transmission.

Claim 2

A system for controlling the air/fuel ratio of the air and fuel mixture supplied to an internal combustion engine of a vehicle having an automatic transmission selectively operable between neutral and drive conditions, the system comprising: means for sensing the temperature of the engine; means for providing a first schedule of air/fuel ratios as a function of engine temperature, the first schedule of air/fuel ratios representing the desired temperature dependent air/fuel ratio of the mixture supplied to the engine when the transmission is in the drive condition; means for providing a second schedule of air/fuel ratios as a function of engine temperature, the second schedule of air/fuel ratios representing the desired temperature dependent air/fuel ratios of the mixture supplied to the engine when the transmission is in the neutral condition; means for sensing the neutral or drive condition of the transmission; means for establishing the air/fuel ratio of the engine in accord with the first schedule of air/fuel ratios during a sensed drive condition of the transmission; and means for establishing the air/fuel ratio of the engine in accord with the second schedule of air/fuel ratios during a sensed neutral condition of the transmission.

Claim 3

The system of claim one wherein the temperature dependent air/fuel ratios in the first schedule of air/fuel ratios are leaner than the temperature dependent air/fuel ratios in the second schedule of air/fuel ratios for corresponding sensed temperatures of the engine.

Claim 4

A system for establishing the warm up air/fuel ratio of the air and fuel mixture supplied to an internal combustion engine of a vehicle having an automatic transmission selectively operable between neutral and drive conditions, the system comprising: means for sensing the temperature of the engine; first memory means for storing a first schedule of air/fuel ratio values corresponding to respective engine temperature values, the first schedule of air/fuel ratio values representing the desired temperature dependent air/fuel ratios of the mixture supplied to the engine when the transmission is in the drive condition; second memory means for storing a second schedule of air/fuel ratio values corresponding to respective engine temperature values, the second schedule of air/fuel ratio values representing the desired temperature dependent air/fuel ratios of the mixture supplied to the engine when the transmission is in the neutral condition; means for sensing the neutral or drive condition of the transmission; means for (A) retrieving the air/fuel ratio value corresponding to the sensed temperature of the engine from the first memory means in response to a sensed drive condition of the transmission and (B) retrieving the air/fuel ratio value corresponding to the sensed temperature of the engine from the second memory means in response to a sensed neutral condition of the transmission; and means for adjusting the air/fuel ratio of the mixture supplied to the engine in accord with the retrieved air/fuel ratio value.

Claim 5

A system for establishing the warm up air/fuel ratio of the air and fuel mixture supplied to an internal combustion engine of a vehicle having an automatic transmission selectively operable between neutral and drive conditions, the system comprising: means for sensing the temperature of the engine; first memory means for storing a first schedule of air/fuel ratio values corresponding to respective engine temperature values, the first schedule of air/fuel ratio values representing the desired temperature dependent air/fuel ratios of the mixture supplied to the engine when the transmission is in the drive condition; second memory means for storing a second schedule of air/fuel ratio values corresponding to respective engine temperature values, the second schedule of air/fuel ratio values representing the desired temperature dependent air/fuel ratios of the mixture supplied to the engine when the transmission is in the neutral condition; means for sensing the neutral or drive condition of the transmission; means for (A) retrieving the air/fuel ratio value corresponding to the sensed temperature of the engine from the first memory means in response to a sensed drive condition of the transmission and (B) retrieving the air/fuel ratio value corresponding to the sensed temperature of the engine from the second memory means in response to a sensed neutral condition of the transmission; and means for adjusting the air/fuel ratio of the mixture supplied to the engine in accord with the retrieved air/fuel ratio value.

Claim 7

A system for establishing the warm up air/fuel ratio of the air and fuel mixture supplied to an internal combustion engine of a vehicle having an automatic transmission selectively operable between neutral and drive conditions and having an engine idle speed controller having a tendency to oscillate at high values of the warm up air/fuel ratio of the mixture supplied to the engine when the transmission is in its neutral condition, the system comprising: means for sensing the temperature of the engine; first memory means for storing a first schedule of air/fuel ratio values corresponding to respective engine temperature values, the first schedule of air/fuel ratio values representing desired high values of warm up temperature dependent air/fuel ratios of the mixture supplied to the engine when the transmission is in the drive condition so as to minimize exhaust gas emissions from the engine; second memory means for storing a second schedule of air/fuel ratio values corresponding to respective engine temperature values, the second schedule of air/fuel ratio values representing desired low values of warm up temperature dependent air/fuel ratios of the mixture supplied to the engine when the transmission is in the neutral condition so as to prevent oscillations of the idle speed controller; means for sensing the neutral or drive condition of the transmission; means for (A) retrieving the air/fuel ratio value corresponding to the sensed temperature of the engine from the first memory means in response to a sensed drive condition of the transmission and (B) retrieving the air/fuel ratio value corresponding to the sensed temperature of the engine from the second memory means in response to a sensed neutral condition of the transmission; and means for adjusting the air/fuel ratio of the mixture supplied to the engine in accord with the retrieved air/fuel ratio value.

Claim 8

A system for establishing the warm up air/fuel ratio of the air and fuel mixture supplied to an internal combustion engine of a vehicle having an automatic transmission selectively operable between neutral and drive conditions and having an engine idle speed controller having a tendency to oscillate at high values of the warm up air/fuel ratio of the mixture supplied to the engine when the transmission is in its neutral condition, the system comprising: means for sensing the temperature of the engine; first memory means for storing a first schedule of air/fuel ratio values corresponding to respective engine temperature values, the first schedule of air/fuel ratio values representing desired high values of warm up temperature dependent air/fuel ratios of the mixture supplied to the engine when the transmission is in the drive condition so as to minimize exhaust gas emissions from the engine; second memory means for storing a second schedule of air/fuel ratio values corresponding to respective engine temperature values, the second schedule of air/fuel ratio values representing desired low values of warm up temperature dependent air/fuel ratios of the mixture supplied to the engine when the transmission is in the neutral condition so as to prevent oscillations of the idle speed controller; means for sensing the neutral or drive condition of the transmission; means for (A) retrieving the air/fuel ratio value corresponding to the sensed temperature of the engine from the first memory means in response to a sensed drive condition of the transmission and (B) retrieving the air/fuel ratio value corresponding to the sensed temperature of the engine from the second memory means in response to a sensed neutral condition of the transmission; and means for adjusting the air/fuel ratio of the mixture supplied to the engine in accord with the retrieved air/fuel ratio value.