Engine Restart Fuel Injection Timing During Deceleration
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Solution Overview
Problem
Existing vehicle controllers struggle to efficiently restart the internal combustion engine during deceleration without proper cranking by the electric motor, especially when the crankshaft rotation speed is above a certain threshold, requiring precise fuel injection timing.
Innovation Solution
A controller that identifies a target cylinder in the compression stroke, calculates the requested injection position based on the crankshaft rotation speed, and outputs a command signal to instruct the target injector to inject fuel at the start crank position only when the crankshaft rotation position is advanced from the start crank position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the internal combustion engine is restarted without cranking by the electric motor when the crankshaft rotation speed is greater than a certain rotation speed, then the productivity is improved, but the manufacturing precision deteriorates
Solution Approach 1:
The controller performs preliminary identification of the target cylinder's stroke position (compression, intake, exhaust, or power stroke) before executing fuel injection. This preliminary action allows the system to prepare the correct injection timing in advance, ensuring precise fuel injection even during rapid engine restart without cranking.
Solution Approach 2:
The controller dynamically adjusts the fuel injection timing parameter based on the detected crankshaft rotation speed and the identified stroke position of the target cylinder. By changing the injection timing parameter according to real-time engine state, the system maintains precise fuel injection delivery despite high-speed restart conditions.
2Use of energy by moving object
If the controller stops the internal combustion engine during deceleration to reduce fuel consumption, then the use of energy by moving object is improved, but the reliability deteriorates
Solution Approach 1:
The controller performs preliminary detection of the target cylinder's stroke position before restart fuel injection. This preliminary identification ensures that when the engine needs to be restarted, the system can immediately determine the correct injection timing based on which stroke the target cylinder is in, thereby ensuring reliable engine restart while maintaining fuel economy during deceleration.
Solution Approach 2:
The controller continuously monitors the crankshaft rotation speed and piston position to detect the stroke position of the target cylinder. This feedback mechanism provides real-time information about engine state, enabling the controller to make accurate decisions about when to restart the engine and how to time the fuel injection, thus ensuring reliable restart after idle reduction.
Data Source
AI summary
When a start request for an internal combustion engine is made with 1) a clutch disconnected, 2) a crankshaft rotating at a specified rotation speed or greater, and 3) fuel injection by an injector stopped, a controller for a vehicle executes: a first process that identifies, from the cylinders, a target cylinder that is in a compression stroke when the request is made; a second process that calculates a requested injection position based on the rotation speed; a third process that calculates, as a start crank position, a rotation position of the crankshaft advanced from the requested injection position by a specified rotation amount; and a fourth process that outputs a command signal that instructs a target injector to inject fuel at the crank position only if the rotation position of the crankshaft obtained when the request is made is advanced from the crank position.