Fuel injection control device and method for internal combustion engine

• US 10,450,993 B2
• Filed: 01/31/2018
• Issued: 10/22/2019
• Est. Priority Date: 02/14/2017
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Kitazume, Akinori, Idogawa, Masanao
• Primary Examiner(s): Huynh, Hai H
• Application Number:
  US15/884,689
• Publication Number:
  US 20180230929A1
• Time in Patent Office: 629 Days
• Field of Search: 123435, 123436, 123491, 123431, 123299, 123300, 701103, 701113, 701110
• CPC Class Codes: F02D 2200/021 Engine temperature
• CPC Class Codes: F02D 2200/04 Engine intake system parameters
• CPC Class Codes: F02D 2200/101 Engine speed
• CPC Class Codes: F02D 41/047 Taking into account fuel evaporation or wall wetting; special correction after fuel cut-off F02D41/126
• CPC Class Codes: F02D 41/068 for warming-up
• CPC Class Codes: F02D 41/3094 the fuel injection being effected by at least two different injectors, e.g. one in the intake manifold and one in the cylinder

Abstract

A fuel injection control device is applied to an internal combustion engine that includes a port injection valve and a direct injection valve. The fuel injection control device includes a port warm-up judgment section, which judges whether the intake port has been warmed up, and an injection mode determination section, which determines the injection mode based on the engine speed and a predicted load rate. When determining the injection mode at the cold operation of the internal combustion engine, the injection mode determination section sets the range of the operation region of the internal combustion engine in which the direct-injection-only mode is selected as the injection mode to be broader in a case in which the port warm-up judgment section has judged that the port has not been warmed up than in a case in which the port warm-up judgment section has judged that the port has been warmed up.

Claims

1. A fuel injection control device for an internal combustion engine configured to be applied to an internal combustion engine including two types of injection valves including a port injection valve, which injects fuel into an intake port, and a direct injection valve, which injects fuel into a cylinder, wherein

the fuel injection control device switches an injection mode between a port-injection-only mode, in which only the port injection valve of the two types of injection valves performs fuel injection, and a direct-injection-only mode, in which only the direct injection valve of the two types of injection valves performs fuel injection,

a state in which a wall temperature of the intake port is higher than or equal to a predetermined wall temperature is defined as a state in which the port has been warmed up,

the fuel injection control device comprises:

a port warm-up judgment section, which is configured to judge whether the port has been warmed up; and

an injection mode determination section, which is configured to determine the injection mode to be executed by the internal combustion engine based on an engine speed and an engine load,

the injection mode determination section is configured such that, when determining the injection mode in a cold operation, in which a coolant temperature of the internal combustion engine is lower than or equal to a predetermined coolant temperature, the injection mode determination section sets, in an operation region of the internal combustion engine specified by the engine speed and the engine load, a range of the operation region in which the direct-injection-only mode is selected as the injection mode to be broader in a case in which the port warm-up judgment section has judged that the port has not been warmed up than in a case in which the port warm-up judgment section has judged that the port has been warmed up, and

wherein the port warm-up judgment section is configured to set a port warm-up judgment value as a value that is increased as the coolant temperature at a time when the startup of the internal combustion engine is initiated is decreased and is configured to judge that the intake port has been warmed up when an accumulated value of an intake air amount or a fuel injection amount after the startup of the internal combustion engine is initiated is greater than or equal to the port warm-up judgment value, regardless of any changes in the coolant temperature after the startup of the internal combustion engine.

2. The fuel injection control device according to claim 1, wherein the port warm-up judgment section is configured to judge that the intake port has been warmed up based on the additional condition that the engine speed is higher than or equal to a predetermined value.

3. A fuel injection control method applied to an internal combustion engine including two types of injection valves including a port injection valve, which injects fuel into an intake port, and a direct injection valve, which injects fuel into a cylinder, wherein

the fuel injection control method includes switching an injection mode between a port-injection-only mode, in which only the port injection valve of the two types of injection valves performs fuel injection, and a direct-injection-only mode, in which only the direct injection valve of the two types of injection valves performs fuel injection, and

a state in which a wall temperature of the intake port is higher than or equal to a predetermined wall temperature is defined as a state in which the port has been warmed up,

the fuel injection control method comprising:

judging whether the port has been warmed up;

determining the injection mode to be executed by the internal combustion engine based on an engine speed and an engine load;

when determining the injection mode in a cold operation, in which a coolant temperature of the internal combustion engine is lower than or equal to a predetermined coolant temperature, setting, in an operation region of the internal combustion engine specified by the engine speed and the engine load, a range of the operation region in which the direct-injection-only mode is selected as the injection mode to be broader in a case in which it is judged that the port has not been warmed up than in a case in which it is judged that the port has been warmed up; and

setting a port warm-up judgment value as a value that is increased as the coolant temperature at a time when the startup of the internal combustion engine is initiated is decreased,

wherein judging whether the intake port has been warmed up includes judging that the intake port has been warmed up when an accumulated value of an intake air amount or a fuel injection amount after the startup of the internal combustion engine is initiated is greater than or equal to the port warm-up judgment value, regardless of any changes in the coolant temperature after the startup of the internal combustion engine.

4. A fuel injection control device for an internal combustion engine configured to be applied to an internal combustion engine including two types of injection valves including a port injection valve, which injects fuel into an intake port, and a direct injection valve, which injects fuel into a cylinder,

the fuel injection control device comprising circuitry, wherein

the circuitry is configured to switch an injection mode between a port-injection-only mode, in which only the port injection valve of the two types of injection valves performs fuel injection, and a direct-injection-only mode, in which only the direct injection valve of the two types of injection valves performs fuel injection,

a state in which a wall temperature of the intake port is higher than or equal to a predetermined wall temperature is defined as a state in which the port has been warmed up,

the circuitry is configured to perform

judging whether the port has been warmed up,

determining the injection mode to be executed by the internal combustion engine based on an engine speed and an engine load, and

when determining the injection mode in a cold operation, in which a coolant temperature of the internal combustion engine is lower than or equal to a predetermined coolant temperature, setting, in an operation region of the internal combustion engine specified by the engine speed and the engine load, a range of the operation region in which the direct-injection-only mode is selected as the injection mode to be broader in a case in which it is judged that the port has not been warmed up than in a case in which it is judged that the port has been warmed up;

and

setting a port warm-up judgment value as a value that is increased as the coolant temperature at a time when the startup of the internal combustion engine is initiated is decreased,

wherein judging whether the intake port has been warmed up includes judging that the intake port has been warmed up when an accumulated value of an intake air amount or a fuel injection amount after the startup of the internal combustion engine is initiated is greater than or equal to the port warm-up judgment value, regardless of any changes in the coolant temperature after the startup of the internal combustion engine.