Engine Controller Fuel Injection Calculation Modes
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Solution Overview
Problem
Conventional internal combustion engine restarting processes are inefficient when the crankshaft is rotating, as they fail to accurately calculate fuel injection amounts due to changing intake air and pressure conditions, leading to suboptimal restarts and increased fuel consumption.
Innovation Solution
A controller with control circuitry that calculates fuel injection amounts based on crankshaft rotation speed, switching between calculation modes to adjust fuel injection dynamically, ensuring successful restarts even when the crankshaft is rotating, and optimizing fuel consumption by quickly transitioning to normal control modes as rotation speed increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conventional restarting process is executed when the crankshaft is rotating, then the engine restart capability is improved, but the fuel injection accuracy deteriorates due to changing intake air and pressure conditions
Solution Approach 1:
The patent applies dynamics by making the fuel injection amount calculation adaptive to changing crankshaft rotation speeds. The system dynamically switches between a first calculation process (for zero rotation speed) and a second calculation process (for non-zero rotation speed), allowing the fuel injection control to respond to real-time operational conditions rather than assuming static conditions.
Solution Approach 2:
The patent changes the calculation parameters based on crankshaft rotation speed. When rotation speed is zero, the system uses parameters based on piston position and intake air amount. When rotation speed is non-zero, it switches to parameters that account for the dynamic pressure changes in the intake passage, thereby maintaining fuel injection accuracy across different operational states.
2Device complexity
If the fuel injection amount is calculated based on piston position only, then the calculation is simple, but the fuel injection accuracy deteriorates when the crankshaft is rotating due to pressure changes
Solution Approach 1:
The system dynamically adjusts the calculation method based on the crankshaft rotation speed. At zero rotation speed, a simpler piston-position-based calculation is used. At non-zero rotation speed, the system transitions to a more complex calculation that incorporates intake air amount and pressure changes, ensuring accuracy without unnecessarily complicating the idle-state control.
Solution Approach 2:
The calculation parameters are changed based on operational conditions. The system switches between using piston position as the primary parameter (when stationary) and using intake air amount and pressure dynamics as primary parameters (when rotating), thereby optimizing the balance between calculation complexity and accuracy for each state.
3Reliability
If the throttle valve is controlled to closed state during automatic stopping, then the stopping reliability is improved, but the intake air flow changes causing fuel injection miscalculation during restart
Solution Approach 1:
The system uses feedback by continuously monitoring the crankshaft rotation speed and using this information to adjust the fuel injection calculation. The rotation speed information provides feedback about the actual intake air flow conditions, allowing the system to compensate for the throttle valve position effects and accurately determine the required fuel injection amount during restart.
Solution Approach 2:
The crankshaft rotation speed serves as an intermediary parameter that links the throttle valve position to the fuel injection calculation. Rather than directly measuring intake air flow, the system uses rotation speed as an intermediate indicator to infer the actual air flow conditions and adjust fuel injection accordingly.
Data Source
AI summary
A controller and a control method for an internal combustion engine, and a memory medium are provided. In a first combustion cylinder, first combustion is caused by control circuitry when the engine is restarted from a state where fuel combustion in cylinders is suspended. An automatic stopping process suspends the fuel combustion in the cylinders and controls a throttle valve to a closed state when a predetermined condition is satisfied. A first calculation process calculates an amount of fuel injected into the first combustion cylinder based on a position of the piston in the first combustion cylinder in a case where a rotation speed of a crankshaft obtained when the restart was requested is zero. A second calculation process calculates the injection amount based on the rotation speed in a case where the rotation speed obtained when the restart was requested is higher than zero.