Control device for compression ignition-type engine

Patent metadata

Field	Value
Publication number	US-9719441-B2
Application number	US-201415032899-A
Country	US
Kind code	B2
Filing date	Oct 23, 2014
Priority date	Oct 29, 2013
Publication date	Aug 1, 2017
Grant date	Aug 1, 2017

Abstract

A control device for a compression ignition engine includes a controller configured to operate an engine body by compression ignition combustion when the engine body operates in a predetermined compression ignition range. When the engine body operates in a predetermined high load range of the compression ignition range, the controller maximizes a filling amount of the cylinder using a gas state adjustment system, and lowers an EGR ratio so that the air-fuel mixture in the cylinder is lean with an excess air ratio λ higher than 1 in a lower speed range, and maximizes the filling amount of the cylinder, and increases the EGR ratio so that the air-fuel mixture in the cylinder has the excess air ratio λ of 1 or lower in a higher speed range than the lower speed range.

First claim

The invention claimed is:

1. A control device for a compression ignition engine, comprising:
an engine body including a cylinder;
a fuel injection valve configured to inject fuel into the cylinder;
a gas state adjustment system configured to adjust a ratio of an amount of fresh air introduced into the cylinder to an amount of exhaust gas to adjust a gas state of the cylinder; and
a controller configured to operate the engine body by compression ignition combustion of an air-fuel mixture in the cylinder when the engine body operates in a predetermined compression ignition range, wherein
when the engine body operates in a predetermined load range of the compression ignition range, which is higher than a predetermined load, the controller
fully opens a throttle valve using the gas state adjustment system, and lowers an EGR ratio, which is a ratio of an amount of the exhaust gas to an entire amount of gas in the cylinder so that the air-fuel mixture in the cylinder is lean with an excess air ratio λ higher than 1 in a lower speed range, in which an engine speed is lower than a predetermined speed, and
fully opens the throttle valve, and increases the EGR ratio so that the air-fuel mixture in the cylinder has the excess air ratio λ of 1 or lower in a higher speed range, in which the engine speed is higher than that in the lower speed range.

2. The control device of claim 1 , further comprising:
an ozonator configured to add ozone to the fresh air introduced into the cylinder, wherein
the controller adds, in the lower speed range of the predetermined range, the ozone to the fresh air introduced into the cylinder using the ozonator.

3. The control device of claim 2 , wherein
the controller allows the ozonator to add the ozone to the fresh air introduced into the cylinder in the lower speed range of the predetermined range when an outside air temperature is lower than or equal to a predetermined temperature.

4. The control device of claim 1 , wherein
the fuel injection valve is configured to directly inject the fuel into the cylinder, and
the controller
sets a time of fuel injection with the fuel injection valve in a first half of a compression stroke or earlier in the lower speed range of the predetermined range, and
sets the time of fuel injection with the fuel injection valve in a second half of the compression stroke or later in the higher speed range of the predetermined range.

5. The control device of claim 2 , wherein
the fuel injection valve is configured to directly inject the fuel into the cylinder, and
the controller
sets a time of fuel injection with the fuel injection valve in a first half of a compression stroke or earlier in the lower speed range of the predetermined range, and
sets the time of fuel injection with the fuel injection valve in a second half of the compression stroke or later in the higher speed range of the predetermined range.

6. The control device of claim 3 , wherein
the fuel injection valve is configured to directly inject the fuel into the cylinder, and
the controller
sets a time of fuel injection with the fuel injection valve in a first half of a compression stroke or earlier in the lower speed range of the predetermined range, and
sets the time of fuel injection with the fuel injection valve in a second half of the compression stroke or later in the higher speed range of the predetermined range.

Assignees

• Mazda Motor

Inventors

• Nagatsu Kazuhiro
• Inoue Atsushi
• Matsumoto Kota
• Kaminaga Takashi
• Miyamoto Toru
• Youso Takashi

Classifications

• F02D21/06

  peculiar to engines having other non-fuel gas added to combustion air · CPC title

• F02D21/10

  having secondary air added to the fuel-air mixture · CPC title

• F02M25/12

  the apparatus having means for generating such gases (using rays and simultaneously generating ozone F02M27/06) · CPC title

• F02D41/0065

  Specific aspects of external EGR control (constructional details of EGR system F02M26/00) · CPC title

• F02B17/005

  having direct injection in the combustion chamber · CPC title