# US 10,480,434 B2 · Control device for internal combustion engine

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- Number: US 10,480,434 B2
- Document ID: US10480434B2
- Status: Granted
- Kind: B2
- Application number: 15/936,619
- Filed: 2018-03-27
- Published: 2018-10-25
- Granted: 2019-11-19
- Earliest claimed: 2017-04-24
- Assignees: Toyota Jidosha Kabushiki Kaisha
- Applicants: Toyota Jidosha Kabushiki Kaisha
- Inventors: Shintaro Hotta
- Web page: https://patentgrep.com/patent/US10480434B2

## CPC

- F02D 41/0052: {Feedback control of engine parameters, e.g. for control of air/fuel ratio or intake air amount}
- F02B 37/18: by bypassing exhaust {from the inlet to the outlet of turbine or to the atmosphere}
- F02D 37/02: one of the functions being ignition
- F02D 41/005: {according to engine operating conditions}
- F02D 41/1454: {the characteristics being an oxygen content or concentration or the air-fuel ratio}
- F02D 41/1475: {Regulating the air fuel ratio at a value other than stoichiometry}
- F02D 41/30: Controlling fuel injection {(F02D41/182, F02D41/24 take precedence)}
- F02D 43/04: using only digital means
- F02P 5/045: {combined with electronic control of other engine functions, e.g. fuel injection (in general F02D37/02)}
- F02P 5/1516: {with means relating to exhaust gas recirculation, e.g. turbo}
- F02D 13/0226: {changing valve lift or valve lift and timing}
- F02D 2041/001: {for engines with variable valve actuation}
- F02D 2200/08: Exhaust gas treatment apparatus parameters
- F02D 2200/1002: Output torque
- F02D 2200/101: Engine speed
- Y02T 10/12: Improving ICE efficiencies
- 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)
- F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G)
- F02P: IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES ({anti-pollution means for internal-combustion engines F02B17/00}; specially adapted for rotary-piston or oscillating-piston engines F02B53/12; {ignition of gas turbine plants F02C7/26; ignition of jet propulsion plants F02K9/95; starting of combustion engines F02N9/00}; ignition of combustion apparatus in general, glowing plugs F23Q; measuring of physical variables in general G01; controlling in general G05; data processing in general G06; electrical components in general see Section H; {ignition coils H01F38/12}; sparking plugs H01T13/00)
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

Assume that a boundary on the air-fuel ration operation is changed from a boundary (i) to a boundary (ii). Then, after the boundary is changed, a high EGR operation region where a target EGR rate is set to a high value overlaps partially with a rich operation region. Therefore, when it is determined that the current operating point exists in the overlapped region, the target EGR rate is forcibly lowered. In addition, the boundary on a drive cam for an intake valve is changed from a boundary (I) to a boundary (II) thereby a region where a small cam is selected is enlarged.

## Claims

### Claim 1

A control device for an internal combustion engine which is configured to control an engine, the engine comprising:
two types of intake cams for driving an intake valve;
a turbocharger including an exhaust turbine and an intake compressor;
an exhaust gas purifying catalyst which is provided on a downstream of the exhaust turbine;
an EGR device which is configured to introduce exhaust gas on the downstream side of the exhaust gas purifying catalyst into an upstream side of the intake compressor as an external EGR gas; and
an ignition device which is configured to ignite air-fuel mixture in a cylinder,
wherein the control device is configured to, based on an operation condition of the engine which is specified by engine torque and engine speed, set a target EGR rate and a target air-fuel ratio and select from the intake cams a drive cam for the intake valve,
wherein the control device is further configured to, when the engine is operated in a high EGR operation region where the target EGR rate is set to a predetermined high EGR rate:
select a first cam as the drive cam; and
set a closing timing of the intake valve to a first crank angle section including a crank angle at which inhalation efficiency is the highest under a condition where engine speed and supercharging pressure are fixed,
wherein the control device is further configured to, when the engine is operated in a low EGR operation region where is located on a higher torque and higher engine speed side relative to the high EGR operation region and the target EGR rate is set to a lower rate than the predetermined high EGR rate:
select a second cam as the drive cam which has smaller operation angle and smaller lift amount than those of the first cam;
set the closing timing of the intake valve to a second crank angle section which is located on an advanced side relative to the first crank angle section and whose inhalation efficiency is lower than that during the first crank angle section; and
change an ignition period of the ignition device to an advance period relative to the ignition period which is set when the engine is operated in the high EGR operation region,
wherein the control device is further configured to, when the engine is operated in an operation region where the high EGR operation region is overlapped with a rich operation region where the target air-fuel is set to a rich value:
change the target EGR rate to a lower value than the predetermined high EGR rate;
select the second cam as the drive cam;
set the closing timing to the second crank angle section; and
change the ignition period to the advance period.

### Claim 2 (depends on 1)

The control device according to claim 1,
wherein the control device comprising:
an EGR map in which the high EGR operation region and the low EGR operation region are associated with the operation condition of the engine;
an air-fuel ratio map in which the rich operation region and a stoichiometric operation region where the target air-fuel ration is set to a stoichiometric ratio are associated with the operation condition of the engine; and
a drive cam map in which a first cam operation region where the first cam is selected as the drive cam and a second cam operation region where the second cam is selected as the drive cam are associated with the operating condition of the engine,
wherein the control device is further configured to:
determine, when the EGR map is superimposed on the air-fuel ratio map, whether or not the rich operation region overlaps with the high EGR operation region; and
change, when it is determined that the rich operation region overlaps with the high EGR operation region, a cam boundary between the first cam operation region and the second cam operation region so that all of the rich operation region fall within the second cam operation region.

### Claim 3 (depends on 2)

The control device according to claim 2,
wherein the engine further comprising a waste gate valve which is provided on a bypass pipe of the exhaust turbine,
wherein the control device further comprising opening degree maps in which an opening degree of the waste gate valve is associated with the opening condition of the engine, wherein the opening degree maps are set for the first cam and the second cam, each of the opening degree maps includes full close lines for specifying the waste gate valve to be fully closed,
wherein the control device is further configured to change, when it is determined that the rich operation region overlaps with the high EGR operation region, the cam boundary so that all of the rich operation region fall within the second cam operation region and also so that the cam boundary locates at a lower engine speed side relative to the full close line of the opening degree map for the second cam.