Skip Fire Cylinder Deactivation Firing Order Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
During skip fire operation in internal combustion engines, valve deactivation/reactivation mechanisms are not fully reliable, leading to unintended combustion events and torque changes, which cause NVH issues and degrade emissions.
Innovation Solution
A method is implemented to dynamically update the firing order based on feedback from ionization sensors, adjusting the commanded firing order to compensate for unintended combustion events by skipping or firing cylinders as needed, ensuring desired torque is maintained.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If valve deactivation/reactivation mechanisms are used during skip fire operation, then fuel economy is improved, but reliability of cylinder firing control deteriorates
Solution Approach 1:
The patent implements a feedback mechanism using ionization sensors to detect actual combustion events in each cylinder. The controller monitors these signals and compares actual combustion status with commanded firing status, then dynamically adjusts the firing order to compensate for any deviations caused by unreliable valve actuation.
Solution Approach 2:
The patent makes the firing order dynamic rather than fixed. The controller continuously updates the commanded firing order based on real-time combustion detection, allowing the system to adapt to varying reliability conditions of valve actuation while maintaining skip fire operation for fuel economy.
2Stability of the object's composition
If dynamic firing order adjustment is implemented, then torque stability is improved, but device complexity increases
Solution Approach 1:
The system uses the engine's own ionization sensors to detect combustion events and automatically adjusts the firing order without requiring external intervention or complex additional hardware. The control system self-corrects based on feedback from the engine's existing diagnostic capabilities.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively minimizes the impact of unreliable valve actuation during skip fire operations, maintaining desired torque and reducing NVH issues and emissions by dynamically adjusting the firing order in response to unintended combustion events.
Implementation Method 1
combustion may be detected based on feedback from an ionization sensor
Data Source
AI summary
Embodiments for operating an engine with skip fire are provided. In one example, a method comprises during a skip fire mode or during a skip fire mode transition, port injecting a first fuel quantity to a cylinder of an engine, the first fuel quantity based on a first, predicted air charge amount for the cylinder and lean of a desired air-fuel ratio, and direct injecting a second fuel quantity to the cylinder, the second fuel quantity based on the first fuel quantity and a second, calculated air charge amount for the cylinder.