Control device for internal combustion engine

Patent metadata

Field	Value
Publication number	US-10107147-B2
Application number	US-201715638692-A
Country	US
Kind code	B2
Filing date	Jun 30, 2017
Priority date	Jul 6, 2016
Publication date	Oct 23, 2018
Grant date	Oct 23, 2018

Abstract

Intake holes at the opposite ends are opened and closed by first intake valves. The middle intake hole is opened and closed by a second intake valve. A control device includes an intake variable valve device. First branch channels are connected to the intake holes and produce a normal tumble flow. A second branch channel is configured such that the flow rate of intake air passing through the middle intake hole is relatively greater on the side closer to the outer periphery of the combustion chamber. Where increasing the flow coefficient is given a higher priority, a three-valve drive mode is selected. Where the strength of the normal tumble flow is enhanced, a two-valve drive mode is selected. Where production of the normal tumble flow is reduced, a one-valve drive mode is selected.

First claim

What is claimed is:

1. A control device for an internal combustion engine that includes:
a spark plug disposed at a combustion chamber top surface of a cylinder;
a fuel injection valve configured to supply a fuel into the cylinder;
three intake holes formed in the combustion chamber top surface, the area of a middle intake hole of the three intake holes being smaller than the sum of the areas of intake holes at opposite ends;
at least one exhaust hole formed in the combustion chamber top surface;
first intake valves configured to open and close the intake holes at the opposite ends;
a second intake valve configured to open and close the middle intake hole;
at least one exhaust valve configured to open and close the at least one exhaust hole;
an intake variable valve device configured to separately control opening and closing of the first intake valves and opening and closing of the second intake valve; and
an intake channel that includes first branch channels and a second branch channel, the first branch channels being connected to the intake holes at the opposite ends and being configured to produce a normal tumble flow that ascends on an intake side and descends on an exhaust side in the cylinder, and the second branch channel being connected to the middle intake hole and being configured such that a flow rate of intake air passing through a space on a side opposite to a center of a combustion chamber is greater than a flow rate of intake air passing through a space on a side of the middle intake hole closer to the center of the combustion chamber,
wherein the control device is programmed, where increasing a flow coefficient of the first branch channels and the second branch channel is given a higher priority than enhancing a strength of the normal tumble flow, to control the intake variable valve device so as to select a first drive mode in which both the first intake valves and the second intake valve are opened and closed,
wherein the control device is programmed, where the strength of the normal tumble flow is enhanced, to control the intake variable valve device so as to select a second drive mode in which the first intake valves are opened and closed while the second intake valve is neither opened nor closed, or the first intake valves are opened and closed while at least one of a lift amount and an operating angle of the second intake valve is set to be smaller than at least one of a lift amount and an operating angle of the second intake valve in the first drive mode, and
wherein the control device is programmed, where production of the normal tumble flow is reduced, to control the intake variable valve device so as to select a third drive mode in which the second intake valve is opened and closed while the first intake valves are neither opened nor closed, or the second intake valve is opened and closed while at least one of a lift amount and an operating angle of the first intake valves is set to be smaller than at least one of a lift amount and an operating angle of the first intake valves in the first drive mode.

2. The control device according to claim 1 ,
wherein the control device is programmed to control the intake variable valve device so as to select the first drive mode if an engine speed is higher than a threshold, and control the intake variable valve device so as to select the second drive mode if the engine speed is equal to or lower than the threshold.

3. The control device according to claim 1 ,
wherein the internal combustion engine includes an EGR device that is configured to feed a part of exhaust gas flowing in an exhaust channel back to the intake channel as an EGR gas, and
wherein the control device is programmed to control the intake variable valve device so as to select the second drive mode if the EGR gas is fed back to the intake channel by using the EGR device.

4. The control device according to claim 1 ,
wherein the control device is programmed to control the intake variable valve device so as to select the second drive mode if a lean combustion operation is performed at a lean air-fuel ratio higher than a stoichiometric air-fuel ratio.

5. The control device according to claim 1 ,
wherein the control device is programmed to control the intake variable valve device so as to select the first drive mode if an Atkinson cycle is used by retarding or advancing a timing of closing of at least one of the first intake valves and the second intake valve.

6. The control device according to claim 1 ,
wherein the control device is programmed to control the intake variable valve device so as to select the second drive mode in a knock region on a low-engine-speed and high-load side.

7. The control device according to claim 1 ,
wherein the control device is programmed to control the intake variable valve device so as to select the third drive mode if a stratified charge combustion operation is performed at a time of starting of the internal combustion engine.

8. The control device according to claim 1 ,
wherein, of the three intake holes, the middle intake hole is disposed farthest from the at least one exhaust hole,
wherein a first mask part is provided around the middle intake hole in a form of a protrusion that surrounds the middle intake hole on a side closer to the center of the combustion chamber in a direction perpendicular to an axis of a crankshaft in a view of the combustion chamber top surface viewed from below along an axis of the cylinder, and
wherein a valve overlap period in which only a period in which the second intake valve is open overlaps with a period in which the at least one exhaust valve is open is provided if the first drive mode is selected in a scavenging region where an intake air pressure is higher than an exhaust gas pressure.

9. The control device according to claim 1 ,
wherein a first mask part is provided around the middle intake hole in a form of a protrusion that surrounds the middle intake hole on a side closer to the center of the combustion chamber in a direction perpendicular to an axis of a crankshaft in a view of the combustion chamber top surface viewed from below along an axis of the cylinder.

10. The control device according to claim 1 ,
wherein second mask parts are provided around the intake holes at the opposite ends in a form of a protrusion that surrounds a corresponding intake hole on a side closer to an outer periphery of the combustion chamber in a direction perpendicular to an axis of a crankshaft in a view of the combustion chamber top surface viewed from below along an axis of the cylinder.

Assignees

• Toyota Motor Co Ltd

Inventors

• Yoshihara Yasushi

Classifications

• F02F2001/245

  the valve stems being orientated at an angle with the cylinder axis · CPC title

• F02B31/087

  having three or more inlet valves · CPC title

• F01L2800/00

  Methods of operation using a variable valve timing mechanism · CPC title

• F01L2001/186

  Split rocking arms, e.g. rocker arms having two articulated parts and means for varying the relative position of these parts or for selectively connecting the parts to move in unison · CPC title

• F02D13/0257

  Independent control of two or more intake or exhaust valves respectively, i.e. one of two intake valves remains closed or is opened partially while the other is fully opened · CPC title