Engine Output Control Apparatus Stall State Management
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Solution Overview
Problem
Existing engine output control systems for vehicles with automatic transmissions face challenges in preventing overheating of torque converter oil during low-speed travel, particularly on steep slopes or when towing, as current methods risk vehicle stalling or slipping due to excessive engine output reduction.
Innovation Solution
An engine output control apparatus that includes sensors for shift range, vehicle speed, engine output state, and temperature, which cumulates a count value to delay engine output suppression control as vehicle speed increases, thereby avoiding stalling and reducing oil temperature rise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If engine output is reduced to prevent torque converter overheating, then oil temperature increases are suppressed, but vehicle may stall or slip on slopes
Solution Approach 1:
The patent applies dynamics by making the engine output suppression control start condition variable based on vehicle speed. Specifically, the control start condition is set to delay as vehicle speed increases, meaning the threshold for initiating engine output suppression changes dynamically with operating conditions. This resolves the contradiction by allowing aggressive cooling at very low speeds while maintaining power availability at higher speeds where stalling risk is lower.
Solution Approach 2:
The patent changes the parameter of control start condition based on vehicle speed. The control start condition is configured to delay as vehicle speed increases, effectively adjusting the threshold parameters for when engine output suppression kicks in. This parameter adaptation allows the system to prevent overheating at low speeds while avoiding unnecessary suppression at higher speeds, thus maintaining vehicle stability.
2Temperature
If engine output suppression control starts immediately when stall conditions are met, then oil overheating is prevented, but vehicle performance is unnecessarily reduced
Solution Approach 1:
The patent applies preliminary action by using a cumulation mechanism that accumulates stall condition occurrences over time before triggering engine output suppression. Instead of reacting immediately to each stall condition, the system preliminarily accumulates evidence of recurring stall conditions and only suppresses power output when the cumulated count reaches a threshold. This prevents unnecessary power reduction during transient conditions while still protecting against overheating during sustained stall states.
3Duration of action of stationary object
If engine output is continuously suppressed to prevent overheating, then oil durability is improved, but vehicle cannot maintain motion on slopes
Solution Approach 1:
The patent applies dynamics by making the engine output suppression control start condition variable based on vehicle speed. The control start condition is set to delay as vehicle speed increases, meaning suppression is more readily triggered at very low speeds where overheating risk is highest, while maintaining higher power availability at speeds where vehicle can maintain motion. This dynamic adjustment protects oil durability during critical low-speed operations without compromising vehicle mobility.
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 system effectively prevents vehicle stalling and overheating of torque converter oil during high-torque, low-speed conditions by delaying engine output suppression, ensuring stable vehicle operation and prolonged component durability.
Implementation Method 1
a torque converter 2 having a pump 21 at an input side and a turbine 22 at an output side... oil (generally, ATF: Automatic Transmission Fluid) that transmits torque from the pump at the input side to the turbine at the output side
Implementation Method 2
oil (generally, ATF: Automatic Transmission Fluid) that transmits torque from the pump at the input side to the turbine at the output side receives a shearing stress and generates heat
Data Source
AI summary
Engine output control apparatus has shift range detecting section detecting shift range of automatic transmission; vehicle speed detecting section detecting vehicle speed; engine output state detecting section detecting engine output state; and controller. The controller performs (a) judgment control judging that torque converter is in a stall state if following judgment conditions (i) to (iii) are satisfied, (i) shift range is drive range, (ii) vehicle speed is equal to or less than predetermined vehicle speed, (iii) engine is in a high output state, (b) cumulation control cumulating a period of agreement of the judgment conditions if the judgment conditions are satisfied, and (c) output suppression control suppressing output of the engine if a control start condition is satisfied by cumulation of the agreement period. The control start condition is set so that as the vehicle speed becomes higher, start of the output suppression control is more delayed.