Engine Control for Unstable Combustion via Exhaust Brake

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Solution Overview

Problem

Internal combustion engines with closed crankcase ventilation systems face uncontrolled behavior due to fluid flow between the crankcase and cylinder space, leading to potential engine damage and safety risks, as existing methods for detecting such behavior are inadequate and may result in severe failures or fires, especially at high engine speeds.

Innovation Solution

A method and system for controlling internal combustion engines that determine uncontrolled behavior by monitoring powertrain disengagement, engine speed increase, and fuel receipt in the cylinder space, allowing for intermittent activation and deactivation of the exhaust brake to reposition the vehicle to a safe location if unsafe, and performing an emergency stop when safe, thereby preventing engine failure and ensuring safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the engine speed threshold for detecting uncontrolled behaviour is set high to maintain vehicle operation at high speeds, then the vehicle can operate at relatively high engine speeds, but detection occurs too late to prevent severe engine failure and fire

Engineering Contradiction:
Improveengine speedVSAvoidengine safety
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent applies preliminary action by detecting uncontrolled behavior at early stages using multiple parameters (engine acceleration, torque, vehicle weight, road grade) before the engine speed reaches dangerous levels. This allows the control system to take preventive action while the vehicle is still in a safe position, rather than waiting for high engine speed thresholds to be triggered too late.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by continuously monitoring multiple engine parameters (acceleration, torque, speed) and comparing them against calculated expected values based on vehicle operating conditions (weight, road grade). This closed-loop feedback system enables real-time detection of deviations indicating uncontrolled behavior, allowing timely intervention before severe failure occurs.

Inventive Principle:
Principle #23Feedback

2Reliability

If an emergency stop is performed immediately upon detecting uncontrolled behaviour, then engine failure is prevented, but vehicle safety is compromised when the vehicle is not in a safe position

Engineering Contradiction:
Improveengine safetyVSAvoidvehicle safety risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies dynamics by adapting the emergency response strategy based on real-time vehicle position and operating conditions. The control system dynamically determines whether to perform immediate emergency stop, gradual deceleration, or continue operation to a safe location, optimizing both engine protection and vehicle safety according to the specific situation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies preliminary action by first determining vehicle position and safety status before executing emergency stop. The control system preliminarily assesses whether the vehicle is in a safe position capable of withstanding emergency stop forces, and only then initiates emergency termination of engine operation, preventing both engine failure and vehicle safety incidents.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If the exhaust brake is intermittently activated and deactivated to reposition the vehicle, then the vehicle can be moved to a safe position, but the control system complexity increases

Engineering Contradiction:
Improvevehicle repositioning capabilityVSAvoidcontrol system complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent applies universality by using the existing exhaust brake system, originally designed for engine braking during normal operation, for the additional function of controlled vehicle repositioning during uncontrolled behavior events. This multi-functional use of existing hardware avoids adding complex new mechanisms while enabling safe vehicle relocation capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent applies periodic action by intermittently activating and deactivating the exhaust brake in controlled cycles to gradually reposition the vehicle to a safe location. This periodic activation pattern provides smooth, controllable movement while maintaining relatively simple control logic compared to continuous actuation or more complex positioning systems.

Inventive Principle:
Principle #19Periodic action

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 effectively detects uncontrolled behavior and mitigates engine failure by allowing controlled engine operation to reposition the vehicle safely, reducing the risk of severe engine damage and improving safety by enabling timely intervention before engine failure occurs.

Implementation Method 1

determining an uncontrolled behaviour due to fluid flow between said crankcase and said cylinder space and combustion of such fluid

Methodology Applied
Scientific EffectFluid flow:

Implementation Method 2

combustion of such fluid

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP3475548B1Method for controlling an internal combustion engine during uncontrolled combustion therein
Publication Date: 2023.03.15 SCANIA CV AB
  • EP3475548B1 patent drawingFigure 1~3
  • EP3475548B1 patent drawingFigure 4~5c
  • EP3475548B1 patent drawingFigure 6

AI summary

The present invention relates to by a method for controlling an internal combustion engine of a vehicle when uncontrolled behaviour has been determined and there is a need for taking the vehicle to a safe position. The vehicle (1) comprises an internal combustion engine (E), the combustion engine (E) comprising a cylinder (C1) having a space (01) arranged to receive air and fuel, a piston (P1) disposed in the cylinder and a crankcase (CC) being in fluid communication with the cylinder (C1). The method comprises the step of determining (S1) an uncontrolled behaviour due to fluid flow between said crankcase (CC) and said cylinder space (01) and combustion of such fluid; and if an uncontrolled behaviour has been determined, determining (S2) whether the vehicle is in a safe position, and, if the vehicle is in a safe position, performing an emergency stop, and; if the vehicle is not in a safe position, operating the engine in order to reposition said vehicle by controlling the exhaust brake (V3) of the vehicle by intermittently activating and deactivating said exhaust brake. The present invention also relates to a system for controlling an internal combustion engine of a vehicle. The present invention also relates to a vehicle. The present invention also relates to a computer program and a computer program product.