Fuel-Cut Intake Air Control for Catalyst Cooling and Deceleration
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Solution Overview
Problem
Existing fuel cut methods to prevent catalyst device overheating in an internal combustion engine lead to decreased engine rotation speed and worsened sense of deceleration, as increasing air intake during fuel cut reduces pumping loss.
Innovation Solution
An engine system with a control unit that adjusts intake air amount based on catalyst temperature and brake operation, ensuring effective cooling of the catalyst while maintaining vehicle deceleration sensation by increasing intake air during brake operation and restricting it during non-brake operation.
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 pumping loss decreases causing the decrease rate of engine rotation speed to slow down and the sense of deceleration worsens
Solution Approach 1:
The patent applies dynamics by making the intake air amount adjustable rather than fixed. The control unit dynamically changes the intake air amount based on real-time catalyst temperature and brake operation status, allowing the system to adapt to different operating conditions and resolve the contradiction between cooling the catalyst and maintaining deceleration sensation.
Solution Approach 2:
The patent changes the parameter of intake air amount based on catalyst temperature and brake operation. When catalyst temperature is high and brake is not operating, the system increases intake air to cool the catalyst. When brake is operating, the system restricts intake air to maintain pumping loss and deceleration sensation, thus resolving the technical contradiction through parameter optimization.
2Temperature
If the intake air amount is increased during fuel cut to cool the catalyst, then the catalyst is cooled effectively, but the engine rotation speed decreases slower and vehicle deceleration performance deteriorates
Solution Approach 1:
The system optimizes the intake air amount parameter based on the combination of catalyst temperature and brake operation status. By changing this parameter dynamically, the system achieves effective catalyst cooling when needed while preserving deceleration performance when the brake is operating, thus resolving the contradiction between temperature control and productivity.
Solution Approach 2:
The control unit uses feedback from catalyst temperature sensors and brake operation status to adjust the intake air amount. This closed-loop control ensures that the system responds appropriately to actual operating conditions, cooling the catalyst when safe to do so while maintaining deceleration performance when the brake is applied.
3Speed
If the intake air amount is restricted during fuel cut to maintain deceleration sensation, then the sense of deceleration is maintained, but the catalyst device temperature rises excessively
Solution Approach 1:
The system dynamically adjusts the intake air amount based on real-time monitoring of catalyst temperature and brake operation status. This dynamic control allows the system to restrict air intake for deceleration performance when the brake is not operating, while increasing air intake to cool the catalyst when temperature becomes excessively high, thus resolving the contradiction.
Solution Approach 2:
The control unit continuously monitors catalyst temperature and brake operation status, using this feedback to adjust the intake air amount appropriately. When catalyst temperature exceeds a threshold and the brake is not operating, the system increases air intake to cool the catalyst. When the brake is operating, the system restricts air intake to maintain deceleration performance, thus resolving the contradiction through intelligent feedback control.
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 device overheating while preventing a worsened sense of deceleration by optimizing intake air control during fuel cut, ensuring efficient cooling and reducing torque shocks.
Implementation Method 1
a catalyst device provided in the exhaust passage to purify exhaust gas
Implementation Method 2
the amount of air drawn into the combustion chamber is increased and a large amount of air is introduced into the exhaust passage, therefore into the catalyst device, to cool the catalyst device with the air
Data Source
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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 a fuel supply device 11; and in implementation of fuel cut, when a catalyst temperature obtained by a catalyst temperature obtaining device is high, the control device implements an intake air amount increase control to control an intake air amount adjustment device 22 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 operation state detection device detects that a brake 81 is in operation, the control device controls the intake air amount adjustment device 22 so that the intake air amount becomes larger than when a brake operation state detection device detects that the brake 81 is in non-operation.