Engine system

Patent metadata

Field	Value
Publication number	US-11591983-B2
Application number	US-202117452531-A
Country	US
Kind code	B2
Filing date	Oct 27, 2021
Priority date	Nov 13, 2020
Publication date	Feb 28, 2023
Grant date	Feb 28, 2023

Abstract

An engine system is provided, including a controller which controls devices of an engine at a given engine speed so that, when a demanded engine load is a first load, a mass ratio (G/F) of intake air inside a cylinder (containing fresh air and burnt gas) to fuel is a first G/F and mixture gas inside the cylinder combusts by flame-propagation, when the demanded load is a second load (<the first load), the G/F is a second G/F (>the first G/F) and an injection center-of-gravity is at a timing such that the entire mixture gas combusts by CI combustion, and when the demanded load is between the first and second loads, the G/F is at a third G/F (between the first and second G/Fs) and the injection center-of-gravity is at a later timing such that at least part of the mixture gas combusts by the CI combustion.

First claim

What is claimed is:

1. An engine system, comprising:
an engine having a cylinder and a piston reciprocatably accommodated in the cylinder;
an injector attached to the engine and configured to inject fuel into the cylinder;
a spark plug attached to the engine and configured to ignite a mixture gas of fuel and intake air, the intake air containing fresh air and burnt gas;
a variable valve operating device connected to an intake valve and an exhaust valve, and configured to control opening and closing of the intake valve and the exhaust valve to adjust a filling amount of the intake air; and
a controller electrically connected to the injector, the spark plug, and the variable valve operating device, and configured to control the injector, the spark plug, and the variable valve operating device according to a demanded load of the engine,
wherein when the engine operates at a given speed and the demanded engine load is a first load, the controller controls the injector and the variable valve operating device to make a mass ratio (G/F) of the intake air inside the cylinder to fuel be at a first G/F, and controls the spark plug so that the mixture gas inside the cylinder combusts by flame propagation,
wherein when the engine operates at the given speed and the demanded engine load is a second load lower than the first load, the controller controls the injector and the variable valve operating device to make the mass ratio be at a second G/F higher than the first G/F, and controls the injector to make an injection center of gravity be at a first timing so that the entire mixture gas inside the cylinder combusts by compression ignition, the injection center of gravity being defined based on an injection timing and an injection amount of fuel during one cycle,
wherein when the engine operates at the given speed and the demanded engine load is lower than the first load and higher than the second load, the controller controls the injector and the variable valve operating device to make the mass ratio be at a third G/F higher than the first G/F and lower than the second G/F, and controls the injector to make the injection center of gravity be at a second timing later than the first timing so that at least part of the mixture gas inside the cylinder combusts by compression ignition, and
wherein when the engine operates at the given speed and the demanded engine load is lower than the first load and higher than the second load, the controller switches between a first injection mode and a second injection mode based on an estimated G/F, and an estimated temperature inside the cylinder at a close timing of the intake valve, the first injection mode being a mode in which the controller controls the injector to inject fuel during each of an intake stroke and a middle period of a compression stroke, and the second injection mode being a mode in which the controller controls the injector to inject fuel during each of the intake stroke and an end period of the compression stroke.

2. The engine system of claim 1 , wherein when the engine operates at the given speed and the demanded engine load is lower than the first load and higher than the second load, the controller inhibits the operation of the spark plug so that the entire mixture gas inside the cylinder combusts by compression ignition.

3. The engine system of claim 1 , wherein when the engine operates at the given speed and the demanded engine load is lower than the first load and higher than the second load, the controller actuates the spark plug so that at least part of the mixture gas inside the cylinder combusts by flame propagation, and the remaining mixture gas combusts by compression ignition.

4. The engine system of claim 1 ,
wherein when the engine operates at the given speed and the demanded engine load is the second load, the controller controls the injector to inject fuel during the intake stroke, and
wherein, when the engine operates at the given speed and the demanded engine load is lower than the first load and higher than the second load, the controller controls the injector to inject fuel during each of the intake stroke and the compression stroke.

5. The engine system of claim 1 , wherein when the engine operates at the given speed and the demanded engine load is the first load, the controller controls the injector to inject fuel during the intake stroke.

6. The engine system of claim 1 , wherein when the engine operates at the given speed and the demanded engine load is the first load, the controller controls the injector to inject fuel in a latter half of the compression stroke.

7. The engine system of claim 1 , wherein the variable valve operating device controls the opening and closing of the intake valve and the exhaust valve so that the burnt gas remains inside the cylinder, or the burnt gas is introduced into the cylinder through the intake valve or the exhaust valve.

8. The engine system of claim 1 , wherein a geometric compression ratio of the engine is 15:1 or above and 30:1 or below.

9. A engine system, comprising:
an engine having a cylinder and a piston reciprocatably accommodated in the cylinder;
an injector attached to the engine and configured to inject fuel into the cylinder;
a spark plug attached to the engine and configured to ignite a mixture gas of fuel and intake air, the intake air containing fresh air and burnt gas;
a variable valve operating device connected to an intake valve and an exhaust valve, and configured to control opening and closing of the intake valve and the exhaust valve to adjust a filling amount of the intake air; and
a controller electrically connected to the injector, the spark plug, and the variable valve operating device, and configured to control the injector, the spark plug, and the variable valve operating device according to a demanded load of the engine,
wherein when the engine operates at a given speed and the demanded engine load is a first load, the controller controls the injector and the variable valve operating device to make a mass ratio (G/F) of the intake air inside the cylinder to fuel be at a first G/F, and controls the spark plug so that the mixture gas inside the cylinder combusts by flame propagation,
wherein when the engine operates at the given speed and the demanded engine load is a second load lower than the first load, the controller controls the injector and the variable valve operating device to make the mass ratio be at a second G/F higher than the first G/F, and controls the injector to make an injection center of gravity be at a first timing so that the entire mixture gas inside the cylinder combusts by compression ignition, the injection center of gravity being defined based on an injection timing and an injection amount of fuel during one cycle,
wherein when the engine operates at the given speed and the demanded engine load is lower than the first load and higher than the second load, the controller controls the injector and the variable valve operating device to make the mass ratio be at a third G/F higher than the first G/F and lower than the second G/F, and controls the injector to make the injection center of gravity be at a second timing later than the first timing so that at least part of the mixture gas inside the cylinder combusts by compression ignition,
wherein when the engine operates at the given speed and the demanded engine load is lower than the first load and higher than the second load, the controller inhibits the operation of the spark plug so that the entire mixture gas inside the cylinder combusts by compression ignition,
wherein when the engine operates at the given speed and the demanded engine load is the second load, the controller controls the injector to inject fuel during an

Assignees

• Mazda Motor

Inventors

• Kaminaga Takashi
• Fujikawa Tatsuya
• Yamakawa Masahisa
• Ito Naoya
• Matsuo Ryohei
• Sasaki Yuta
• Hori Junki
• Muto Mitsuhiro
• Fujii Takuma

Classifications

• Y02T10/40

  Engine management systems · CPC title

• F02D41/402

  Multiple injections · CPC title

• F02P15/02 Primary

  Arrangements having two or more sparking plugs · CPC title

• F02D41/3041

  with means for triggering compression ignition, e.g. spark plug · CPC title

• F02D41/401

  Controlling injection timing (F02D41/402 takes precedence) · CPC title