# US 8,783,014 B2 · Control system for internal combustion engine

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- Number: US 8,783,014 B2
- Document ID: US8783014B2
- Status: Granted
- Kind: B2
- Application number: 13/394,458
- Filed: 2009-09-10
- Published: 2012-06-28
- Granted: 2014-07-22
- Earliest claimed: 2009-09-10
- Assignees: Toyota Jidosha Kabushiki Kaisha
- Applicants: Kazuhiro Itoh
- Inventors: Kazuhiro Itoh
- Web page: https://patentgrep.com/patent/US8783014B2

## CPC

- 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
- F01N 3/2066: {Selective catalytic reduction [SCR]}
- F01N 3/208: {Control of selective catalytic reduction [SCR], e.g. by adjusting the dosing of reducing agent}
- F02M 26/15: in relation to engine exhaust purifying apparatus
- F01N 2610/02: the substance being ammonia or urea
- F01N 2610/1453: Sprayers or atomisers; Arrangement thereof in the exhaust apparatus
- F02M 26/05: High pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust system upstream of the turbine and reintroduced into the intake system downstream of the compressor
- F02M 26/10: having means to increase the pressure difference between the exhaust and intake system, e.g. venturis, variable geometry turbines, check valves using pressure pulsations or throttles in the air intake or exhaust system
- F02M 26/24: with two or more coolers
- Y02T 10/12: Improving ICE efficiencies
- F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- 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)
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

The present invention is intended to suppress the inflow of an ammonia derived compound to an EGR passage. In the present invention, in an exhaust system, there is arranged an ammonia derived compound addition means in such a position as to enable at least a part of the ammonia derived compound added therefrom to arrive at a connection portion of the EGR passage. Further, in the present invention, the inflow of the ammonia derived compound added from the ammonia derived compound addition means into the EGR passage is suppressed by a suppression means.

## Claims

### Claim 1

A control system for an internal combustion engine, the control system comprising:
an EGR system that has an EGR passage connected at its one end to an exhaust system of the internal combustion engine, and at its other end to an intake system of the internal combustion engine, and that introduces a part of an exhaust gas flowing through the exhaust system into the intake system through the EGR passage as an EGR gas;
an NOx selective reduction catalyst that is arranged in the exhaust system;
an ammonia derived compound addition device configured to add an ammonia derived compound, which is a reducing agent, into the exhaust gas, and arranged in the exhaust system at an upstream side of the NOx selective reduction catalyst in such a position as to enable at least a part of the ammonia derived compound thus added to arrive at a connection portion of the EGR passage; and
at least one controller configured to suppress an inflow of the ammonia derived compound added by the ammonia derived compound addition device into the EGR passage, the controller further configured to suppress the inflow of the ammonia derived compound added by the ammonia derived compound addition device into the EGR passage by decreasing a flow rate of the EGR gas flowing through the EGR passage at a time when the ammonia derived compound is added by the ammonia derived compound addition device, in comparison with a case when the ammonia derived compound is not added by the ammonia derived compound addition device.

### Claim 2 (depends on 1)

The control system as set forth in claim 1, wherein
the EGR passage has the one end thereof connected to a portion of the exhaust system at a downstream side of the NOx selective reduction catalyst; and
at the time of decreasing the flow rate of the EGR gas flowing through the EGR passage, the controller makes the flow rate of the EGR gas larger in cases where an amount of the ammonia derived compound flowing out to the downstream side of the NOx selective reduction catalyst without being used for the reduction of NOx in the NOx selective reduction catalyst is small, in comparison with a case where the amount of the ammonia derived compound flowing out to the downstream side of the NOx selective reduction catalyst without being used for the reduction of NOx in the NOx selective reduction catalyst is large.

### Claim 3 (depends on 1)

The control system as set forth in claim 1, wherein
the EGR passage is a low pressure EGR passage that has the one end thereof connected to a portion of the exhaust system at a downstream side of a turbine of a turbocharger, and the other end thereof connected to a portion of the intake system at an upstream side of a compressor of the turbocharger;
the EGR device further includes a high pressure EGR passage that has one end thereof connected to a portion of the exhaust system at an upstream side of the turbine of the turbocharger, and the other end thereof connected to a portion of the intake system at a downstream side of the compressor of the turbocharger; and
at the time of decreasing the flow rate of the EGR gas flowing through the low pressure EGR passage when the ammonia derived compound is added by the ammonia derived compound addition device, the controller decreases the flow rate of the EGR gas flowing through the high pressure EGR passage in cases where the circulation of the EGR gas in the low pressure EGR passage is not stopped.

### Claim 4 (depends on 1)

The control system as set forth in claim 1, wherein
the EGR passage is a low pressure EGR passage that has the one end thereof connected to a portion of the exhaust system at a downstream side of a turbine of a turbocharger, and the other end thereof connected to a portion of the intake system at an upstream side of a compressor of the turbocharger;
the EGR device further includes a high pressure EGR passage that has one end thereof connected to a portion of the exhaust system at an upstream side of the turbine of the turbocharger, and the other end thereof connected to a portion of the intake system at a downstream side of the compressor of the turbocharger; and
the controller increases the flow rate of the EGR gas flowing through the high pressure EGR passage at the time of decreasing the flow rate of the EGR gas flowing through the low pressure EGR passage when the ammonia derived compound is added by the ammonia derived compound addition device.

### Claim 5 (depends on 1)

The control system as set forth in claim 1, wherein
the EGR passage is a low pressure EGR passage that has the one end thereof connected to a portion of the exhaust system at a downstream side of a turbine of a turbocharger, and the other end thereof connected to a portion of the intake system at an upstream side of a compressor of the turbocharger.

### Claim 6 (depends on 1)

The control system as set forth in claim 1, wherein
the EGR passage is a high pressure EGR passage that has the one end thereof connected to a portion of the exhaust system at an upstream side of a turbine of a turbocharger, and the other end thereof connected to a portion of the intake system at a downstream side of a compressor of the turbocharger.

### Claim 7

A control system for an internal combustion engine, the control system comprising:
an EGR system that has an EGR passage connected at its one end to an exhaust system of the internal combustion engine, and at its other end to an intake system of the internal combustion engine, and that introduces a part of an exhaust gas flowing through the exhaust system into the intake system through the EGR passage as an EGR gas;
an NOx selective reduction catalyst that is arranged in the exhaust system;
an ammonia derived compound addition device configured to add an ammonia derived compound, which is a reducing agent, into the exhaust gas, and arranged in the exhaust system at an upstream side of the NOx selective reduction catalyst in such a position as to enable at least a part of the ammonia derived compound thus added to arrive at a connection portion of the EGR passage; and
at least one controller configured to suppress an inflow of the ammonia derived compound added by the ammonia derived compound addition device into the EGR passage, the controller further configured to suppress the inflow of the ammonia derived compound added by the ammonia derived compound addition device into the EGR passage at a time when the EGR gas is introduced into the intake system by way of the EGR passage, by making an amount of addition of the ammonia derived compound by the ammonia derived compound addition device smaller in comparison with a case when the introduction of the EGR gas into the intake system is stopped.

### Claim 8 (depends on 7)

The control system as set forth in claim 7, wherein
the EGR passage has the one end thereof connected to a portion of the exhaust system at a downstream side of the NOx selective reduction catalyst; and
at the time of making the amount of addition of the ammonia derived compound from the ammonia derived compound addition device smaller, the controller makes the amount of addition of the ammonia derived compound larger in cases where the amount of the ammonia derived compound flowing out to the downstream side of the NOx selective reduction catalyst without being used for the reduction of NOx in the NOx selective reduction catalyst is small, in comparison with a case where the amount of the ammonia derived compound flowing out to the downstream side of the NOx selective reduction catalyst without being used for the reduction of NOx in the NOx selective reduction catalyst is large.

### Claim 9 (depends on 7)

The control system as set forth in claim 7, wherein
the EGR passage is a low pressure EGR passage that has the one end thereof connected to a portion of the exhaust system at a downstream side of a turbine of a turbocharger, and the other end thereof connected to a portion of the intake system at an upstream side of a compressor of the turbocharger.

### Claim 10 (depends on 7)

The control system as set forth in claim 7, wherein
the EGR passage is a high pressure EGR passage that has the one end thereof connected to a portion of the exhaust system at an upstream side of a turbine of a turbocharger, and the other end thereof connected to a portion of the intake system at a downstream side of a compressor of the turbocharger.