Ignition Timing Control for Smooth Cruise Mode Transition
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Solution Overview
Problem
Existing ignition timing control systems for engines face challenges in maintaining drivability and smooth transitions when switching between torque-valuing and fuel-conserving ignition timings, leading to a sense of incongruity for the driver and potential degradation in engine performance during state changes.
Innovation Solution
An ignition timing controlling apparatus that uses an ignition timing map, an ignition timing correction unit, and advance angle target maps to stepwise adjust ignition timings, advancing or retarding them in fixed cycles based on engine speed to transition smoothly between torque-valuing and fuel-conserving modes, ensuring linear power output and maintaining drivability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If ignition timing is changed from torque-valuing mode to fuel-conserving mode, then fuel consumption is improved, but drivability and engine response deteriorate
Solution Approach 1:
The ignition timing control system dynamically adjusts the ignition timing based on the detected running state. When in cruise state, the system advances ignition timing to fuel-conserving mode for improved fuel economy. When acceleration or deceleration is detected, the system retards ignition timing back to torque-valuing mode to maintain drivability and engine response. This dynamic switching resolves the contradiction by adapting ignition timing to current operational needs.
Solution Approach 2:
The system changes the ignition timing parameter based on the vehicle's running state. By detecting whether the vehicle is in cruise state or acceleration/deceleration state, the control unit adjusts the ignition timing parameter between two different regimes: advanced timing for fuel efficiency during cruise, and retarded timing for torque response during dynamic operations. This parameter change approach allows optimization of either fuel consumption or drivability depending on operational conditions.
2Speed
If ignition timing is changed abruptly between modes, then transition speed is improved, but power output stability and drivability deteriorate
Solution Approach 1:
The system uses periodic detection cycles to monitor the vehicle's running state and adjust ignition timing accordingly. Rather than making abrupt changes, the control unit continuously monitors whether the vehicle is in cruise or acceleration/deceleration state and adjusts ignition timing in a controlled, periodic manner. This periodic action ensures smooth transitions that maintain power output stability while still achieving the desired mode changes.
Data Source
AI summary
An ignition timing controlling apparatus for an engine includes an ignition timing map in which high-torque timings are stored, an ECU for changing a high-torque timing obtained from the ignition timing map into a fuel-conserving ignition timing, and an advance angle target amount map in which advance angle target amounts with which the high-torque timing is to be changed into the fuel-conserving ignition timing are stored. The ECU is operable to calculate an advance angle target amount for each of cylinders of the engine based on the advance angle target amount map when a running state of a vehicle is in a cruize state in which little acceleration or deceleration is included, and also to execute advance angle control of changing the ignition timing of each of the cylinders stepwise with respect to the advance angle target amount for each of the cylinders.