Fuel injection control device and method for internal combustion engine

A fuel injection control method for an internal combustion engine, wherein

• the internal combustion engine includes
• a first bank having a first cylinder,
• a second bank having a second cylinder,
• a first fuel injection valve configured to supply fuel to the first cylinder,
• a second fuel injection valve configured to supply fuel to the second cylinder,
• a first fuel storage member, which is connected to the first fuel injection valve and is configured to store fuel to be supplied to the first fuel injection valve,
• a second fuel storage member, which is connected to the second fuel injection valve and is configured to store fuel to be supplied to the second fuel injection valve, wherein the second fuel storage member is different from the first fuel storage member and communicates with the first fuel storing member, and
• a pressure sensor configured to detect a fuel pressure in the first fuel storage member,
• the fuel injection control method comprises:
• executing an estimating process to estimate fuel pressure in the first fuel storage member and fuel pressure in the second fuel storage member;
• and
• executing an injection valve operating process to operate the first and second fuel injection valves such that, when pressure in a fuel injection period that is the pressure estimated in the estimating process is high, the fuel injection period is shorter than when the pressure in the fuel injection period is low,
• the estimating process includes
• estimating the fuel pressure in the first fuel storage member based on a detection value of the pressure sensor and a cycle of pulsation in the first fuel storage member, which is determined in accordance with an interval of fuel injections in the first bank, and
• estimating the fuel pressure in the second fuel storage member by assuming that a phase of a periodic fluctuation of the fuel pressure in the second fuel storage member and a phase of a periodic fluctuation of the fuel pressure in the first fuel storage member are in antiphase.

A non-transitory computer readable medium that stores a program for causing a processor to execute a fuel injection control process for an internal combustion engine, wherein

• the internal combustion engine includes
• a first bank having a first cylinder,
• a second bank having a second cylinder,
• a first fuel injection valve configured to supply fuel to the first cylinder,
• a second fuel injection valve configured to supply fuel to the second cylinder,
• a first fuel storage member, which is connected to the first fuel injection valve and is configured to store fuel to be supplied to the first fuel injection valve,
• a second fuel storage member, which is connected to the second fuel injection valve and is configured to store fuel to be supplied to the second fuel injection valve, wherein the second fuel storage member is different from the first fuel storage member and communicates with the first fuel storing member, and
• a pressure sensor configured to detect a fuel pressure in the first fuel storage member,
• the fuel injection control process includes:
• an estimating process to estimate fuel pressure in the first fuel storage member and fuel pressure in the second fuel storage member;
• and
• an injection valve operating process to operate the first and second fuel injection valves such that, when pressure in a fuel injection period that is the pressure estimated in the estimating process is high, the fuel injection period is shorter than when the pressure in the fuel injection period is low,
• the estimating process includes
• estimating the fuel pressure in the first fuel storage member based on a detection value of the pressure sensor and a cycle of pulsation in the first fuel storage member, which is determined in accordance with an interval of fuel injections in the first bank, and
• estimating the fuel pressure in the second fuel storage member by assuming that a phase of a periodic fluctuation of the fuel pressure in the second fuel storage member and a phase of a periodic fluctuation of the fuel pressure in the first fuel storage member are in antiphase.