Engine Fuel-Cut Air Control for Catalyst Cooling and Smooth Deceleration
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Solution Overview
Problem
Existing engine control systems that increase air intake during fuel cut to cool the catalyst device worsen the driver's sense of deceleration and can cause torque shocks, especially at low gear stages, while failing to prevent catalyst overheating effectively.
Innovation Solution
A control system that adjusts intake air amount based on catalyst temperature, brake operation, and gear stage, using a control device to increase intake air during fuel cut when the brake is applied and at high gear stages to cool the catalyst while ensuring smooth deceleration and preventing torque shocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the amount of air drawn into the combustion chamber is increased during fuel cut to cool the catalyst device, then the catalyst device temperature is reduced, but the driver's sense of deceleration worsens due to decreased pumping loss
Solution Approach 1:
The patent applies dynamics by making the intake air amount adjustment dynamic based on real-time detection of brake operation state. The control device switches between different intake air amount control modes: when brake operation is detected, a first control mode is applied with a specific intake air amount; when brake operation is not detected, a second control mode is applied with a different intake air amount. This dynamic adjustment resolves the contradiction by adapting the air intake strategy to the actual deceleration context, ensuring catalyst cooling when braking is active while maintaining appropriate pumping loss when braking is not active.
Solution Approach 2:
The patent changes the parameter of intake air amount based on the detection result of the brake sensor. By detecting whether the brake device is operating, the control device adjusts the intake air amount to different levels (first intake air amount vs. second intake air amount). This parameter change strategy allows the system to optimize both catalyst temperature control and driver's sense of deceleration by selecting appropriate air intake levels according to the actual braking state.
2Temperature
If the intake air amount is increased during fuel cut to cool the catalyst device, then the catalyst device temperature is reduced, but torque shocks occur especially at low gear stages
Solution Approach 1:
The patent changes the intake air amount parameter based on brake operation detection to prevent torque shocks. When brake operation is detected, the control device applies a first intake air amount control that is optimized to avoid sudden torque changes. This parameter adjustment prevents the harmful effect of torque shocks while maintaining the beneficial effect of catalyst cooling, as the brake-operated condition indicates a controlled deceleration scenario where torque fluctuations can be managed.
Solution Approach 2:
The patent uses feedback from the brake sensor to adjust the intake air amount control strategy. The brake sensor provides real-time information about brake operation state, which the control device uses to determine the appropriate intake air amount. This feedback mechanism allows the system to respond to actual vehicle deceleration conditions and adjust air intake accordingly, preventing torque shocks while ensuring catalyst cooling when needed.
3Temperature
If the intake air amount is increased during fuel cut, then the catalyst device is cooled more effectively, but the pumping loss decreases causing slower engine rotation speed reduction
Solution Approach 1:
The patent applies dynamics by dynamically adjusting the intake air amount based on brake operation detection. When the brake sensor detects brake operation, the control device implements a first intake air amount control that balances catalyst cooling with maintaining engine rotation speed reduction. When brake operation is not detected, a second intake air amount control is applied. This dynamic control strategy resolves the contradiction by adapting air intake to the actual deceleration需求, ensuring both catalyst temperature control and appropriate engine speed reduction characteristics.
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
Prevents catalyst overheating while maintaining a smooth deceleration sensation and reducing torque shocks, enhancing vehicle ride comfort and performance by optimizing intake air management during fuel cut operations.
Implementation Method 1
a catalyst device provided in the exhaust passage to purify exhaust gas
Implementation Method 2
a large amount of air is introduced into the exhaust passage and therefore into the catalyst device, and the catalyst device is cooled with the air
Data Source
AI summary
When an accelerator opening degree decreases to be lower than a predetermined accelerator determination opening degree, a control device implements a fuel cut that stops fuel injection by an injector; and in implementation of fuel cut, when a catalyst temperature is high, the control device implements an intake air amount increase control to control an intake air amount adjustment device so that an intake air amount is larger than when a catalyst temperature is low, and in implementation of the intake air amount increase control, when a brake sensor detects that a brake is in operation, the control device controls the intake air amount adjustment device so that the intake air amount becomes larger than when the brake sensor detects that the brake is in non-operation.