Engine Throttle Control for Low Pressure Responsiveness
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Solution Overview
Problem
Internal combustion engines with turbo-superchargers experience decreased responsiveness of intake air amount when accelerating under low atmospheric pressure, as the control apparatus relies heavily on the turbo-supercharger, which has lower responsiveness compared to the throttle valve, leading to increased dependence on turbo-supercharger control and reduced acceleration performance.
Innovation Solution
A control apparatus that switches between high and low atmospheric pressure steady-state characteristics for the throttle and waste gate valve, allowing the throttle valve to secure a margin for intake air amount control, thereby improving responsiveness by utilizing the throttle valve's higher responsiveness, especially under low atmospheric pressure conditions, and restricting the throttle valve's operating speed to prevent compressor outlet pressure drops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If intake air amount control is executed that is dependent on the turbo-supercharger under low atmospheric pressure, then the control range of intake pressure is extended, but the responsiveness of intake air amount control decreases
Solution Approach 1:
The control system is segmented into two independent control paths: throttle valve control for rapid response and turbo-supercharger control for extended range. The throttle valve handles immediate intake air amount adjustments while the turbo-supercharger provides broader control capability, allowing both responsiveness and adaptability to be maintained simultaneously through divided control functions
Solution Approach 2:
The control system dynamically switches between throttle valve-dominated control and turbo-supercharger-dominated control based on operating conditions. Under low atmospheric pressure, the system optimizes the coordination between these two control elements, adjusting their relative contributions to maintain both responsiveness and extended control range
2Quantity of substance
If the throttle opening degree is increased to obtain the same intake air amount under low atmospheric pressure, then the intake air amount is maintained, but the margin for control by the throttle valve is reduced
Solution Approach 1:
The waste gate valve serves as an intermediary control element that works in coordination with the throttle valve. By adjusting the waste gate valve opening degree, the system can maintain the required intake air amount while preserving throttle valve control margin, as the waste gate valve compensates for the reduced throttle authority under low atmospheric pressure conditions
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
The solution enhances the responsiveness of intake air amount from a medium load region to a high load region by securing a margin for control using the throttle valve, improving acceleration performance under low atmospheric pressure without excessive fuel consumption or compressor outlet pressure drops.
Implementation Method 1
a compressor (22a) which is disposed in an intake passage (14) and supercharges intake air
Implementation Method 2
a turbine (22b) which is disposed in an exhaust passage (16) and operates by means of exhaust energy
Data Source
Figure 1
Figure 2(A)~2(C)
Figure 3(A)~3(C)
AI summary
A control apparatus for an internal combustion engine of the present invention switches a steady-state characteristic that defines a relation between an engine load factor and a throttle opening degree between a high atmospheric pressure steady-state characteristic and a low atmospheric pressure steady-state characteristic in accordance with whether or not the atmospheric pressure is higher than a predetermined value. According to the low atmospheric pressure steady-state characteristic, a throttle opening degree corresponding to an identical engine load factor is set to a smaller value compared to the high atmospheric pressure steady-state characteristic in a medium load region, and the throttle opening degree is set so as to increase as the engine load factor increases towards a full load in a region on the side of a higher load factor than the medium load region. When a request is not made to increase the intake air amount with a high response under a low atmospheric pressure, the control apparatus refers to the low atmospheric pressure steady-state characteristic and calculates a target throttle opening degree corresponding to a target engine load factor. In contrast, when a request is made to increase the intake air amount with a high response under a low atmospheric pressure, the control apparatus sets the target throttle opening degree so as to be a larger value than the target throttle opening degree calculated as described above.