# US 2018/0320626 A1 · Methods and system for central fuel injection

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- Number: US 2018/0320626 A1
- Document ID: US20180320626A1
- Status: Published application
- Kind: A1
- Application number: 15/586,146
- Filed: 2017-05-03
- Published: 2018-11-08
- Earliest claimed: 2017-05-03
- Assignees: Ford Global Technologies, LLC
- Applicants: Ford Global Technologies, LLC
- Inventors: Gopichandra Surnilla; Adithya Pravarun Re Ranga; Mohannad Hakeem; Calvin Trescott; Joseph Norman Ulrey; Peter C. Moilanen
- Web page: https://patentgrep.com/patent/US20180320626A1

## CPC

- F02D 41/3094: {the fuel injection being effected by at least two different injectors, e.g. one in the intake manifold and one in the cylinder}
- F01N 3/021: by means of filters
- F01N 3/10: by thermal or catalytic conversion of noxious components of exhaust
- F01N 3/36: Arrangements for supply of additional fuel
- F01N 9/00: Electrical control of exhaust gas treating apparatus (monitoring or diagnostic devices for exhaust-gas treatment apparatus F01N11/00; conjoint electrical control of two or more combustion engine functions F02D43/00)
- F01N 11/002: {the diagnostic devices measuring or estimating temperature or pressure in, or downstream of the exhaust apparatus}
- F01N 11/007: {the diagnostic devices measuring oxygen or air concentration downstream of the exhaust apparatus}
- F02D 41/0087: {Selective cylinder activation, i.e. partial cylinder operation (deceleration cut-off F02D41/123)}
- F02D 41/023: {in relation with the gear ratio shifting (conjoint control for improving gear change B60W30/19)}
- F02D 41/0235: {in relation with the state of the exhaust gas treating apparatus (control of exhaust gas treating apparatus per se F01N)}
- F02D 41/0255: {to accelerate the warming-up of the exhaust gas treating apparatus at engine start}
- F02D 41/0295: {Control according to the amount of oxygen that is stored on the exhaust gas treating apparatus}
- F02D 41/064: {at cold start (F02D41/067 takes precedence)}
- F02D 41/10: for acceleration
- F02D 41/12: for deceleration {(F02D41/0005, F02D41/107 take precedence)}
- F02D 41/123: {the fuel injection being cut-off}
- F02D 41/126: {transitional corrections at the end of the cut-off period}
- F02D 41/1441: {Plural sensors}
- F02D 41/1454: {the characteristics being an oxygen content or concentration or the air-fuel ratio}
- F02D 41/1456: {with sensor output signal being linear or quasi-linear with the concentration of oxygen}
- F02D 41/146: {the characteristics being an NOx content or concentration}
- F02D 41/1461: {of the exhaust gases emitted by the engine}
- F02D 41/1495: {Detection of abnormalities in the air/fuel ratio feedback system}
- F02M 69/046: {for injecting into both the combustion chamber and the intake conduit}
- F01N 2250/02: filtering and catalytic conversion
- F01N 2430/06: by varying fuel-air ratio, e.g. by enriching fuel-air mixture
- F01N 2560/025: for measuring or detecting O2, e.g. lambda sensors
- F01N 2560/06: the means being a temperature sensor
- F01N 2900/08: said parameters being related to the engine
- F01N 2900/1402: Exhaust gas composition
- F01N 2900/1602: Temperature of exhaust gas apparatus
- F01N 2900/1606: Particle filter loading or soot amount
- F01N 2900/1614: NOx amount trapped in catalyst
- F01N 2900/1624: Catalyst oxygen storage capacity
- F01N 2900/1626: Catalyst activation temperature
- F02D 2041/001: {for engines with variable valve actuation}
- F02D 2200/0414: Air temperature
- F02D 2200/0814: Oxygen storage amount
- F02D 2200/1002: Output torque
- F02D 2200/101: Engine speed
- F02M 25/028: into the charge intakes
- F02M 26/06: Low pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust downstream of the turbocharger turbine and reintroduced into the intake system upstream of the compressor
- Y02T 10/40: Engine management systems
- F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W)
- F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16)
- F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

Methods and systems are provided for adjusting engine operating conditions for reduction of NOx emissions. In one example, immediately after a fuel shut-off event, in response to an oxygen content of an exhaust catalyst being higher than a threshold, manifold charge cooling may be increased by increasing the portion of fuel delivered to the engine via manifold injection relative to the portion to fuel delivered via one or more of port and direct injection. By increasing manifold cooling, NOx production may be reduced.

## Claims

### Claim 1

A method, comprising:
adjusting a first portion of fuel delivered to an engine via manifold injection relative to a second portion of fuel delivered to the engine via one or more of port and direct injection based on an estimated oxygen content of an exhaust catalyst, the estimated oxygen content estimated immediately after a fuel shut-off event.

### Claim 2 (depends on 1)

The method of claim 1, wherein the adjusting includes increasing the first portion of fuel delivered to the engine via manifold injection while correspondingly decreasing the second portion of fuel delivered via the one or more of port and direct injection in response to the estimated oxygen content of the exhaust catalyst increasing above a threshold oxygen content.

### Claim 3 (depends on 2)

The method of claim 2, wherein the adjusting further includes, maintaining engine operation with the increased first portion of fuel and the decreased second portion of fuel until the estimated oxygen content of the exhaust catalyst falls below the threshold oxygen content, and then decreasing the first portion of fuel delivered to the engine via manifold injection while correspondingly increasing the second portion of fuel delivered via the one or more of port and direct injection.

### Claim 4 (depends on 2)

The method of claim 2, wherein the adjusted first portion of fuel delivered to the engine via manifold injection is based on the estimated oxygen content of the exhaust catalyst, the first portion increased as the estimated oxygen content of the exhaust catalyst increases above the threshold oxygen content.

### Claim 5 (depends on 4)

The method of claim 4, wherein the second portion of fuel delivered via the one or more of port and direct injection is adjusted based on the first portion to maintain an exhaust air-fuel ratio.

### Claim 6 (depends on 1)

The method of claim 1, wherein the adjusting further includes, in the second portion of fuel, adjusting a ratio of fuel delivered via port injection relative to fuel delivered via direct injection based on a particulate matter load of an exhaust particulate matter filter coupled upstream/downstream of the exhaust catalyst, the adjusting including increasing the ratio of fuel delivered via direct injection relative to port injection when the particulate matter load on the particulate matter filter is lower than a threshold.

### Claim 7 (depends on 2)

The method of claim 2, wherein the increasing the first portion of fuel includes increasing the first portion of fuel delivered to an engine via manifold injection relative to the second portion of fuel delivered via one or more of port and direct injection for a first number of engine cycles immediately after the fuel shut-off event, and during the first number of engine cycles, operating the engine with a richer than stoichiometric exhaust air-fuel ratio.

### Claim 8 (depends on 7)

The method of claim 7, wherein the first number of engine cycles is based on an exhaust catalyst oxygen loading, the first number of cycles increased as the exhaust catalyst oxygen loading increases.

### Claim 9 (depends on 1)

The method of claim 1, wherein the fuel shut-off event includes a deceleration fuel shut off event responsive to a lower than threshold operator torque demand.

### Claim 10 (depends on 1)

The method of claim 1, wherein the fuel shut-off event includes a transient fuel shut-off event responsive to a transmission gear upshift.

### Claim 11 (depends on 1)

The method of claim 1, further comprising, in response to a higher than threshold engine intake manifold temperature, increasing the first portion of fuel delivered to the engine via manifold injection while correspondingly decreasing the second portion of fuel delivered via the one or more of port and direct injection until the engine intake manifold temperature decreases below the threshold engine intake manifold temperature.

### Claim 12 (depends on 1)

The method of claim 1, further comprising, in response to a lower than threshold exhaust catalyst temperature, increasing the first portion of fuel delivered to the engine via manifold injection while correspondingly decreasing the second portion of fuel delivered via the one or more of port and direct injection until the exhaust catalyst temperature increases above the threshold exhaust catalyst temperature.

### Claim 13

An engine method, comprising:
in response to an exhaust NOx level downstream of an exhaust catalyst, predicted based on engine operating conditions, being higher than a threshold level, providing a total fuel mass as a first amount of fuel injected into an engine intake manifold via a central fuel injector and a second, remaining amount of fuel injected via one or more of port and direct injectors, the first amount of fuel higher than the second amount of fuel.

### Claim 14 (depends on 13)

The method of claim 13, wherein the engine operating conditions include a cold-start condition, and wherein the total fuel mass provided as the first amount of fuel injected via the central fuel injector and the second remaining amount of fuel injected via the one or more of port and direct injectors is maintained until a light-off temperature of the exhaust catalyst is attained.

### Claim 15 (depends on 14)

The method of claim 14, wherein the engine operating conditions include a fuel shut-off event, the method further comprising, upon resumption of fueling at an end of the fuel shut-off event, in response to a higher than threshold oxygen content in the exhaust catalyst, injecting the first amount of fuel injected via the central fuel injector and injecting the second remaining amount of fuel injected via one or more of port and direct injectors until the oxygen content in the exhaust catalyst reduces to below the threshold.

### Claim 16 (depends on 13)

The method of claim 13, wherein the engine operating conditions include a higher than threshold intake manifold temperature, and wherein the first amount of fuel injected via the central fuel injector and the second remaining amount of fuel injected via the one or more of port and direct injectors is maintained until the intake manifold temperature drops below the threshold temperature.

### Claim 17 (depends on 13)

The method of claim 13, wherein the second amount of fuel injected via one or more of port and direct injectors is adjusted based on maldistribution of the first amount of fuel injected via the central fuel injector among a plurality of engine cylinders, the adjusting including increasing direct injection of fuel to a first cylinder in response to the first cylinder receiving a lower portion of the first amount of fuel relative to fuel received by remaining engine cylinders.

### Claim 18

An engine system, comprising:
an engine intake manifold including a manifold air temperature sensor;
a plurality of engine cylinders;
one or more direct injectors configured to direct inject a fuel into one or more of the plurality of cylinders;
one or more port injectors configured to port inject the fuel into one or more of the plurality of cylinders;
a central fuel injector to inject the fuel into the engine intake manifold;
an engine exhaust manifold including an exhaust passage, an exhaust catalyst coupled to the exhaust passage, and an exhaust oxygen sensor coupled to the exhaust passage upstream of the exhaust catalyst; and
a controller with computer-readable instructions stored on non-transitory memory for:
in response to one of a higher than threshold oxygen content in the exhaust catalyst and a higher than threshold engine intake manifold temperature, selectively increasing a ratio of fuel delivered via the central fuel injector relative to fuel delivered via each of the direct injectors and the port injectors, the oxygen content estimated via the exhaust oxygen sensor and the engine intake manifold temperature via the manifold air temperature sensor.

### Claim 19 (depends on 18)

The system of claim 18, wherein the controller contains further instructions for:
maintaining engine fueling with the increased ratio of manifold injected delivered via the central fuel injector relative to each of the direct injectors and port injectors until each of the oxygen content in the exhaust catalyst drops below the threshold oxygen content and the engine intake manifold temperature drops below the threshold temperature, and then then adjusting the ratio based on engine speed and engine load.

### Claim 20 (depends on 18)

The system of claim 18, wherein selectively increasing the ratio of manifold injected fuel includes selectively increasing a pulse width of the central fuel injector while decreasing a pulse width of the port injector and the direct injector, the pulse width of the central fuel injector based on each of the oxygen content of the exhaust catalyst and the engine intake manifold temperature, the pulse width of the central fuel injector increased as one or more of the oxygen content of the exhaust catalyst increases above the threshold oxygen content and the engine intake manifold temperature increases above the threshold temperature.