Control system for compression ignition engine

Patent metadata

Field	Value
Publication number	US-2020032736-A1
Application number	US-201916457137-A
Country	US
Kind code	A1
Filing date	Jun 28, 2019
Priority date	Jul 26, 2018
Publication date	Jan 30, 2020
Grant date	—

Abstract

A control system for a compression ignition engine is provided, which includes a combustion chamber, a throttle valve, an injector, an ignition plug, a sensor, and a controller. A changing module of the controller outputs a signal to the throttle valve so that an air amount increases more than before a demand of changing from a first mode to a second mode, and outputs to the injector a signal to increase a fuel amount according to the air amount increase so that an air-fuel ratio of mixture gas becomes at or substantially at a stoichiometric air-fuel ratio, and outputs to the ignition plug a signal to retard an ignition timing so that an engine torque increase caused by the fuel amount increase is reduced. The changing module reduces the retarding of the ignition timing when the ignition timing is determined to have reached a retard limit.

First claim

What is claimed is:

1 . A control system for a compression ignition engine, comprising:
a combustion chamber of the engine defined by a cylinder, a piston configured to reciprocate inside the cylinder, and a cylinder head closing one end of the cylinder; a throttle valve configured to adjust an amount of air delivered to the combustion chamber; an injector attached to the cylinder head and configured to inject fuel to be supplied into the combustion chamber; an ignition plug disposed so as to be oriented in the combustion chamber and configured to ignite a mixture gas inside the combustion chamber; a sensor configured to measure a parameter related to operation of the engine; and a controller having circuitry connected with the throttle valve, the injector, the ignition plug, and the sensor, configured to perform a calculation in response to measurement signals from the sensor and output signals to the throttle valve, the injector, and the ignition plug, wherein the controller is configured to execute a first mode module in which the engine is operated in a first mode, a second mode module in which the engine is operated in a second mode, and a changing module to change a mode from the first mode to the second mode in response to a change demand, wherein the first mode module outputs the signals to the injector and the throttle valve so that a fuel amount becomes an amount according to a load of the engine and an air-fuel ratio of the mixture gas becomes a first air-fuel ratio, and outputs an ignition signal to the ignition plug so that a portion of the mixture gas starts combustion accompanied by flame propagation by a forcible ignition of the ignition plug, and a remaining portion of unburnt mixture gas then combusts by self-ignition, wherein the second mode module outputs the signals to the injector and the throttle valve so that the fuel amount becomes the amount according to the engine load and the air-fuel ratio of the mixture gas becomes a second air-fuel ratio higher than the first air-fuel ratio, and outputs the ignition signal to the ignition plug so that a portion of the mixture gas starts combustion accompanied by flame propagation by a forcible ignition of the ignition plug, and a remaining portion of unburnt mixture gas then combusts by self-ignition, wherein the changing module outputs the signal to the throttle valve so that the air amount increases more than before the change demand, and outputs to the injector a signal to increase the fuel amount according to the increase in the air amount so that the air-fuel ratio of the mixture gas becomes a stoichiometric air-fuel ratio or a substantially stoichiometric air-fuel ratio, and outputs to the ignition plug a signal to retard an ignition timing so that a torque increase of the engine caused by the increase in the fuel amount is reduced, and wherein the changing module reduces the retarding of the ignition timing when the ignition timing is determined to have reached a retard limit.

2 . The control system of claim 1 , wherein when the ignition timing is determined to have reached the retard limit, the changing module continues the increasing of the fuel amount and increases a load of an alternator driven by the engine.

3 . The control system of claim 1 , wherein when the air amount is determined to have reached a given amount, the changing module ends the increasing of the fuel amount and the retarding of the ignition timing, and permits that the second mode module starts the second mode.

4 . The control system of claim 1 , wherein the changing module changes the mode from the first mode to the second mode, while the torque of the engine is maintained at a constant or substantially constant torque.

5 . The control system of claim 1 , wherein the retard limit is on a retard side as an engine speed is lower and the load is higher, and on an advance side as the engine speed is higher and the load is lower.

6 . The control system of claim 1 , further comprising an exhaust gas recirculation (EGR) valve configured to adjust an amount of EGR gas introduced into the combustion chamber,
wherein the changing module outputs the signal to the EGR valve so that the EGR amount decreases more than before the change demand.

7 . The control system of claim 1 ,
wherein the controller is further configured to adjust a strength of swirl inside the combustion chamber by adjusting an opening of a swirl valve, and wherein the changing module outputs the signal to the swirl valve so that the opening of the swirl valve becomes smaller than before the change demand.

8 . The control system of claim 1 , wherein the first air-fuel ratio is a stoichiometric air-fuel ratio or a substantially stoichiometric air-fuel ratio, and the second air-fuel ratio is 25:1 or higher.

9 . A control system for a compression ignition engine, comprising:
a combustion chamber of the engine defined by a cylinder, a piston configured to reciprocate inside the cylinder, and a cylinder head closing one end of the cylinder; a throttle valve configured to adjust an amount of air delivered to the combustion chamber; an injector attached to the cylinder head and configured to inject fuel to be supplied into the combustion chamber; an ignition plug disposed so as to be oriented in the combustion chamber and configured to ignite a mixture gas inside the combustion chamber; a sensor configured to measure a parameter related to operation of the engine; and a controller having circuitry connected with the throttle valve, the injector, the ignition plug, and the sensor, configured to perform a calculation in response to the measurement signal from the sensor and output signals to the throttle valve, the injector, and the ignition plug, wherein the controller includes a first mode module in which the engine is operated in a first mode, a second mode module in which the engine is operated in a second mode, and a changing module to change a mode from the second mode to the first mode in response to a change demand, wherein the first mode module outputs the signals to the injector and the throttle valve so that a fuel amount becomes an amount according to a load of the engine and an air-fuel ratio of the mixture gas becomes a first air-fuel ratio, and outputs an ignition signal to the ignition plug so that a portion of the mixture gas starts combustion accompanied by flame propagation by a forcible ignition of the ignition plug, and a remaining portion of unburnt mixture gas then combusts by self-ignition, wherein the second mode module outputs the signals to the injector and the throttle valve so that the fuel amount becomes the amount according to the load of the engine and the air-fuel ratio of the mixture gas becomes a second air-fuel ratio higher than the first air-fuel ratio, and outputs the ignition signal to the ignition plug so that a portion of the mixture gas starts combustion accompanied by flame propagation by a forcible ignition of the ignition plug, and a remaining portion unburnt mixture gas combusts by self-ignition, wherein the changing module outputs the signal to the throttle valve so that the air amount decreases more than before the change demand, and maintains the fuel amount until the air-fuel ratio of the mixture gas reaches a particular air-fuel ratio smaller than the second air-fuel ratio after the reducing of the air amount is started, wherein when the air-fuel ratio of the mixture gas is determined to have reached the particular air-fuel ratio, the changing module continues the reducing of the air amount, outputs to the injector a signal to increase the fuel amount so that the air-fuel ratio of the mixture gas becomes a stoichiometric air-fuel ratio or a substantially stoichi

Assignees

• Mazda Motor

Inventors

• Masuda Yuta
• Higashio Masayoshi
• Sunagare Yugou
• Ito Michio
• Ujihara Kenko
• Matsushima Yuto

Classifications

• F02D2041/0015

  for engines with means for controlling swirl or tumble flow, e.g. by using swirl valves · CPC title

• F02D37/02 Primary

  one of the functions being ignition · CPC title

• F02D41/0002

  Controlling intake air · CPC title

• F02D41/38

  of the high pressure type · CPC title

• F02D41/1461

  of the exhaust gases emitted by the engine · CPC title