JP-2026074701-A - Control device for multi-cylinder internal combustion engines

Abstract

[Problem] To further suppress variations in the air-fuel ratio between cylinders during the purging process. [Solution] The multi-cylinder internal combustion engine 10 is equipped with a fuel vapor processing mechanism 90 for performing a purging process that introduces fuel vapor adsorbed by the canister 92 into the intake passage 13. The control device 200 performs the following processes: calculates a cylinder-specific correction coefficient based on a cylinder-specific air-fuel ratio correction coefficient that compensates for variations in fuel vapor distribution between cylinders and a reflection coefficient corresponding to the vapor concentration of the purge gas introduced into the intake passage 13; and calculates the fuel injection amount for each cylinder by correcting the basic injection amount for each cylinder with the cylinder-specific correction coefficient. [Selection Diagram] Figure 1

Inventors

• 安部 司
• 交野 高明
• 石松 健一
• 橋本 研治

Assignees

• トヨタ自動車株式会社

Dates

Publication Date

20260507

Application Date

20241021

Claims (1)

1. A control device applicable to a multi-cylinder internal combustion engine equipped with a fuel vapor treatment mechanism for performing a purging process that introduces fuel vapor adsorbed in a canister into the intake passage, A process for calculating cylinder-specific correction coefficients based on cylinder-specific air-fuel ratio correction coefficients that compensate for variations in fuel vapor distribution between cylinders, and reflection coefficients corresponding to the vapor concentration of purge gas introduced into the intake passage, A control device for a multi-cylinder internal combustion engine that performs the process of calculating the fuel injection amount for each cylinder by correcting the basic injection amount for each cylinder using the aforementioned cylinder-specific correction coefficient.

Description

This invention relates to a control device for a multi-cylinder internal combustion engine. An internal combustion engine is known that includes a fuel vapor treatment mechanism that adsorbs fuel vapor generated in the fuel tank onto a canister and performs a purging process to introduce the adsorbed fuel vapor into the intake passage (for example, Patent Document 1, etc.). In a multi-cylinder internal combustion engine, variations in fuel vapor distribution between cylinders occur, resulting in variations in the air-fuel ratio between cylinders. Therefore, the control device for an internal combustion engine described in Patent Document 1 calculates a correction coefficient to compensate for these variations in fuel vapor distribution between cylinders. The control device then corrects the basic injection amount of each cylinder using the calculated correction coefficient, thereby suppressing these variations in the air-fuel ratio between cylinders. Japanese Patent Publication No. 2001-173485 Figure 1 is a schematic diagram showing an internal combustion engine and control device in one embodiment.Figure 2 is a flowchart showing the processing procedure executed by the control device of the same embodiment. Below, one embodiment of a control device for a multi-cylinder internal combustion engine will be described with reference to Figures 1 and 2. <Configuration of internal combustion engine and control system> As shown in Figure 1, the internal combustion engine 10 is equipped with a plurality of cylinders 10a, and an intake passage 13 is connected to the intake port of each cylinder 10a. A throttle valve 14 is provided in the intake passage 13 to adjust the amount of intake air. Each cylinder 10a has a combustion chamber equipped with a fuel injection valve 11. In the combustion chamber of each cylinder 10a, a mixture of air drawn in through the intake passage 13 and fuel injected from the fuel injection valve 11 is ignited by a spark discharge and combusted. The exhaust gas generated by the combustion of the mixture in the combustion chamber is discharged into an exhaust passage 15 connected to the exhaust port of the internal combustion engine 10. A three-way catalyst 17 is provided in the exhaust passage 15. This three-way catalyst 17 oxidizes hydrocarbons (HC) and carbon monoxide (CO) contained in the exhaust to produce water and carbon dioxide. Furthermore, the three-way catalyst 17 reduces nitrogen oxides (NOx) contained in the exhaust to produce nitrogen. The internal combustion engine 10 is equipped with a fuel vapor treatment mechanism 90 for introducing fuel vapor generated in the fuel tank 91 into the intake passage 13 and treating it within the cylinder 10a. The fuel vapor treatment mechanism 90 includes a canister 92 for adsorbing fuel vapor generated in the fuel tank 91, and a purge passage 94 for introducing the fuel vapor adsorbed by the canister 92 to a point downstream of the throttle valve 14 in the intake passage 13. The fuel vapor treatment mechanism 90 also includes a purge valve 93 located in the middle of the purge passage 94 to adjust the flow rate of the purge gas flowing through the purge passage 94. The purge gas is a mixture of fresh air and evaporated fuel introduced from the canister 92 into the intake passage 13. The control device 200 is equipped with a CPU and memory, and the CPU executes programs stored in the memory to perform various controls on the internal combustion engine 10. The control device 200 receives detection signals from various sensors. For example, the control device 200 receives a detection signal from a first air-fuel ratio sensor 51, which is located upstream of the three-way catalytic converter 17 in the exhaust passage 15 and detects the upstream air-fuel ratio AFf. The control device 200 also receives a detection signal from a second air-fuel ratio sensor 52, which is located downstream of the three-way catalytic converter 17 in the exhaust passage 15 and detects the downstream air-fuel ratio AFr. The control device 200 also receives a detection signal from a crank angle sensor 53, which detects the rotation angle of the crankshaft of the internal combustion engine 10. Based on the detection signal from the crank angle sensor 53, the control device 200 calculates the engine speed NE of the internal combustion engine 10. The control device 200 also receives a detection signal from an air flow meter 54, which detects the intake air volume GA. Based on the engine speed NE and intake air volume GA, the control device 200 calculates the engine load ratio KL. The engine load ratio KL represents the ratio of the current cylinder inflow air volume to the cylinder inflow air volume when the internal combustion engine 10 is operating steadily under full load. The cylinder inflow air volume is the amount of air flowing into each cylinder during the intake stroke. The control device 200 controls the fuel injection from the fuel injection valve 11 and the open