Dynamic Engine Speed Control for Transient Stall Prevention

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Solution Overview

Problem

Construction machines like wheel loaders face engine stalling issues during transient events due to demanding load demands that exceed steady-state torque capabilities, necessitating a method to manage load demand independently of engine throttle.

Innovation Solution

The system dynamically controls engine speed by determining the current engine speed, gear setting, and hydraulic system parameters. If the engine speed is decreasing and the actual speed is less than the target speed, especially when the gear is engaged and hydraulic system parameters exceed a threshold, the engine speed is controlled to be higher than the target speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the engine throttle is set proportional to target engine speed, then the engine operates efficiently under steady-state conditions, but the engine stalls during transient events when load demand exceeds torque capability

Engineering Contradiction:

Improveengine operation reliabilityVSAvoidthrottle control simplicity

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The system dynamically adjusts engine speed setpoint based on operating conditions. During transient events, when hydraulic load demand exceeds steady-state torque capability, the controller increases the target engine speed above the normal throttle-proportional setpoint to ensure the engine can deliver sufficient torque and avoid stalling.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the engine speed parameter dynamically. Instead of maintaining a fixed relationship between throttle position and target engine speed, the system modifies the target engine speed parameter upward during transient high-load conditions to prevent engine stall, while maintaining the simpler throttle-proportional control during normal operation.

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If the engine speed is controlled to match the target speed during transient events, then the engine operates smoothly, but the engine speed becomes insufficient to handle increased load demands

Engineering Contradiction:

Improveengine speed stabilityVSAvoidengine torque output

Core Design Contradiction:

Stability of the object's compositionVSPower

Solution Approach 1:

The controller detects transient conditions in advance and proactively increases the target engine speed before the engine speed drops. By anticipating the need for increased power output and adjusting the speed setpoint accordingly, the system maintains both stability and sufficient torque capability during transient events.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from engine operating conditions (load demand, current speed, throttle position) to continuously adjust the target engine speed. When sensors detect that the engine is entering a transient high-load state, the feedback loop modifies the speed setpoint to ensure adequate torque delivery while maintaining stable operation.

Inventive Principle:

Principle #23Feedback

3Use of energy by moving object

If the engine throttle is reduced during function execution, then fuel consumption decreases, but the engine may stall when load demand exceeds available torque

Engineering Contradiction:

Improvefuel consumptionVSAvoidengine stall prevention

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The system maintains dynamic adaptability by allowing the target engine speed to deviate from the simple throttle-proportional relationship during transient events. This dynamic adjustment ensures that even when throttle is reduced for fuel efficiency, the engine speed can be increased to maintain torque capability and prevent stalling during high-load transient conditions.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS12292010B2Dynamic engine speed setting during transient event

Publication Date: 2025.05.06 CUMMINS INC

AI summary

A vehicle system and method of controlling a vehicle engine are provided. The method includes determining a speed of an engine in the vehicle system including a hydraulic system and a vehicle propulsion system operatively coupled to the engine. The method includes determining that the engine speed is decreasing and an actual engine speed is less than a target engine speed, and determining a current gear setting and one or more operating parameters of the hydraulic system in response to determining that the engine speed is decreasing and the actual engine speed is less than the target engine speed. The method, in response to the current gear setting being engaged and the one or more operating parameters being greater than a predetermined threshold value, includes controlling the engine speed to be higher than the target engine speed.