Adaptive Engine Braking Control for Stall Prevention
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Solution Overview
Problem
Existing systems fail to prevent engine stalls during cold engine operation and rapid engine speed decreases, as they do not adequately account for these conditions, leading to machine downtime and inefficiency.
Innovation Solution
A controller is used to determine the temperature and speed of the power source and machine, disabling engine braking if the temperature is below a threshold or if the speed is below predetermined levels, thereby preventing stalls during cold mode or slow-speed operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If engine braking is enabled at traditional engine speeds (800-1000 rpm), then engine braking function is available, but engine stalling occurs during cold operation and rapid speed decrease
Solution Approach 1:
The patent applies dynamics by making the engine braking control adaptive rather than fixed. The controller dynamically adjusts engine braking activation based on real-time monitoring of engine speed, coolant temperature, and throttle position. This allows the system to enable engine braking at slower speeds when conditions are favorable (warm engine, gradual deceleration) while disabling it when conditions are unfavorable (cold engine, rapid deceleration), thus resolving the contradiction between preventing stalls and maintaining slow-speed braking capability
Solution Approach 2:
The patent changes the parameters governing engine braking activation from fixed traditional thresholds to variable thresholds based on engine temperature and operating conditions. The controller modifies the effective engine braking activation speed threshold dynamically - raising it during cold operation and lowering it during warm operation - thereby preventing stalls while preserving slow-speed braking capability when appropriate
2Reliability
If engine braking is disabled during cold operation to prevent stalling, then engine stalling is prevented, but slow-speed engine braking capability is lost
Solution Approach 1:
The patent applies local quality by applying different engine braking control strategies to different operating conditions rather than a uniform approach. The controller evaluates specific local conditions (engine temperature, throttle position, rate of speed decrease) and applies engine braking only when those local conditions are favorable. This allows slow-speed engine braking to be available in appropriate local conditions (warm engine, gradual deceleration) while preventing stalls in unfavorable conditions (cold engine, rapid deceleration), thus maintaining productivity without compromising reliability
3Loss of energy
If traditional fuel cut-off timing is used during engine deceleration, then fuel economy is improved, but engine stalls occur during rapid speed decrease
Solution Approach 1:
The patent applies preliminary action by proactively delaying fuel cut-off timing when rapid engine deceleration is detected, before the engine speed drops to dangerous levels. The controller monitors the rate of speed decrease and, upon detecting rapid deceleration, maintains fuel supply longer than traditional timing would dictate, giving the engine time to recover smoothly without stalling. This preliminary intervention prevents the harmful effect (stalling) while minimizing the energy loss (extended fuel consumption only during the critical recovery period)
Data Source
AI summary
A system to prevent engine stalls for a machine having a power source is disclosed. The power source is in communication with a controller, which is configured to determine the temperature of the power source and compare the temperature of the power source to a predetermined threshold temperature. The controller is configured to disable power source braking if the temperature of the power source is less than the threshold temperature. The controller is further configured to determine the power source speed and the travel speed of the machine, and disable power source braking if the power source speed and machine travel speed are less than predetermined thresholds.