System and method for a motor vehicle with reduced fuel enrichment after a fuel cutoff event

Patent metadata

Field	Value
Publication number	US-11085390-B2
Application number	US-201916696134-A
Country	US
Kind code	B2
Filing date	Nov 26, 2019
Priority date	Nov 26, 2019
Publication date	Aug 10, 2021
Grant date	Aug 10, 2021

Abstract

A control system for a fuel cutoff system of a motor vehicle includes a fuel cutoff module that generates a fuel cutoff signal for disabling a supply of fuel to an engine, in response to the fuel cutoff module detecting a deceleration fuel cutoff (DFCO) event. The control system further includes an oxygen storage module determining an amount of oxygen accumulated in a catalyst and comparing this amount to an oxygen storage capacity (OSC) of the catalyst, in response to the fuel cutoff module determining the DFCO event. The control system further includes an intake valve timing module generating a phasing signal to actuate a plurality of cam phasers to reduce a flow rate of oxygen to the catalyst, in response to the fuel cutoff module determining the DFCO event and the oxygen storage module determining that the amount of oxygen stored in the catalyst is less than the OSC.

First claim

What is claimed is:

1. A control system for a fuel cutoff system of a motor vehicle, the control system comprising:
a fuel cutoff module determining a deceleration fuel cutoff event and generating a fuel cutoff signal for disabling a supply of fuel to an internal combustion engine in response to the fuel cutoff module detecting the deceleration fuel cutoff event;
an oxygen storage module determining an amount of oxygen accumulated in a catalyst disposed downstream of the engine, and the oxygen storage module comparing the amount of oxygen to an oxygen storage capacity of the catalyst, in response to the fuel cutoff module determining the deceleration fuel cutoff event; and
an intake valve timing module generating a phasing signal to actuate a plurality of cam phasers to move to first and seconded activated phaser states for modifying a valve timing to reduce a flow rate of oxygen to the catalyst, in response to the fuel cutoff module determining the deceleration fuel cutoff event and in further response to the oxygen storage module determining that the amount of oxygen stored in the catalyst is less than the oxygen storage capacity.

2. The control system of claim 1 wherein the oxygen storage module is configured to receive a first oxygen signal from a first oxygen sensor disposed upstream of the catalyst and determine an amount of oxygen entering the catalyst in response to the first oxygen signal and a mass air flow of oxygen into the catalyst.

3. The control system of claim 2 wherein the oxygen storage module is configured to receive a second oxygen signal from a second oxygen sensor disposed downstream of the catalyst, and the oxygen storage module is configured to determine the amount of oxygen downstream from the catalyst in response to the second oxygen signal.

4. The control system of claim 3 wherein the fuel cutoff module is configured to receive an engine speed signal from an engine speed sensor coupled to the engine, and the fuel cutoff module is configured to determine an engine speed of the engine in response to the engine speed signal.

5. The control system of claim 4 wherein the oxygen storage module is configured to receive a pressure signal from a pressure sensor coupled to an intake manifold with the pressure signal being indicative of a manifold pressure, and the oxygen storage module is further configured to receive a temperature signal from a temperature sensor coupled to the intake manifold, with the temperature signal being indicative of a manifold temperature;
in response to the oxygen storage module receiving the pressure signal and the temperature signal, the oxygen storage module is configured to measure the pressure of airflow through the intake manifold and the temperature of airflow through the intake manifold; and
in response to the measured engine speed, the measured manifold pressure, and the measured manifold temperature, the oxygen storage module determines the mass air flow into the catalyst.

6. The control system of claim 5 wherein the fuel cutoff module determines the deceleration fuel cutoff event in response to the fuel cutoff module determining that a vehicle speed is greater than a vehicle speed threshold and in further response to an accelerator position being less than a position threshold.

7. The control system of claim 6 wherein the deceleration fuel cutoff event occurs in response to the engine outputting a negative engine torque.

8. A fuel cutoff system for a motor vehicle, the fuel cutoff system comprising:
an internal combustion engine comprising:
a plurality of engine cylinders;
a plurality of intake valves operably engaged with the cylinders where each of the intake valves is movable between opened and closed positions;
a plurality of exhaust valves operably engaged with the cylinders where each of the exhaust valves is movable between opened and closed positions;
a throttle body movable from a closed position to an open position for flowing air to the engine cylinders; and
a plurality of pistons movable between top and bottom positions within an associated one of the cylinders, and a location of the pistons when the associated intake valves and exhaust valves are disposed in the closed position defines a valve timing;

a control system comprising:
a fuel cutoff module generating a fuel cutoff signal for disabling a supply of fuel to the engine cylinders and moving the throttle body toward the closed position in response to the fuel cutoff module detecting a deceleration fuel cutoff event;
an oxygen storage module determining an amount of oxygen accumulated in a catalyst and comparing the amount of oxygen to an oxygen storage capacity of the catalyst in response to the fuel cutoff module determining the deceleration fuel cutoff event; and
an intake valve timing module generating a phasing signal to actuate a plurality of cam phasers to move to first and second activated phaser states, in response to the fuel cutoff module determining the deceleration fuel cutoff event and in further response to the oxygen storage module determining that the amount of oxygen stored in the catalyst is less than the oxygen storage capacity; and

a plurality of cam phasers operably engaged to the intake valves and the exhaust valves, the cam phasers being movable to the first and second activated phaser states where the cam phaser modifies the valve timing to reduce the flow rate of oxygen to the catalyst
wherein the cam phaser is movable to the first activated phaser state, where the pistons are disposed in a predetermined default position when the associated intake valves are in the closed position, such that oxygen flows to the catalyst at a first flow rate;
wherein the cam phaser is further movable to the second activated phaser state where the valve timing is modified such that the closing of the intake valves is one of advanced or retarded by a cam angle that reduces the flow rate of oxygen from the first flow rate to a second flow rate that is lower than the first flow rate;
wherein the engine cylinders remain held in a fixed activated state where the intake valves and the exhaust valves continuously reciprocate between opened and closed positions while each of the pistons move between top and the bottom positions.

9. The fuel cutoff system of claim 8 , wherein the cam phaser is movable to the second activated phaser state in response to the intake valve timing module determining that the amount of oxygen accumulated in the catalyst less than the oxygen storage capacity.

10. The fuel cutoff system of claim 9 wherein the oxygen storage module is configured to receive a first oxygen signal from a first oxygen sensor disposed upstream of the catalyst and determine an amount of oxygen entering the catalyst in response to the first oxygen signal and a mass air flow into the catalyst.

11. The fuel cutoff system of claim 10 wherein the oxygen storage module is configured to receive a second oxygen signal from a second oxygen sensor disposed downstream of the catalyst, and the oxygen storage module is configured to determine the amount of oxygen in exhaust gas downstream from the catalyst in response to the second oxygen signal.

12. The fuel cutoff system of claim 11 wherein the fuel cutoff module is configured to receive an engine speed signal from an engine speed sensor coupled to the engine, and the fuel cutoff module is configured to determine an engine speed of the engine in response to the engine speed signal.

13. The fuel cutoff system of claim 12 wherein the oxygen storage module is configured to receive a pressure signal from a pressure sensor coupled to an intake manifold with the pressure signal bei

Assignees

• Gm Global Tech Operations Llc

Inventors

• Gallon Robert
• Smith Michael A
• Pedigo Matt

Classifications

• F02D41/1401

  characterised by the control or regulation method (F02D41/1473, F02D41/1477 take precedence) · CPC title

• F02D41/123

  the fuel injection being cut-off · CPC title

• F02D41/009

  using means for generating position or synchronisation signals · CPC title

• F02D41/0005 Primary

  during deceleration · CPC title

• F02D41/1454

  the characteristics being an oxygen content or concentration or the air-fuel ratio · CPC title