Combustion Engine Cylinder Segmentation for Fast Brake Deactivation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Compression release engine brakes in internal combustion engines take a long time to deactivate, impairing driving feel and anti-lock braking system functionality, and require additional auxiliary brakes to meet legislative requirements, especially in varying temperatures.

Innovation Solution

A method and control arrangement that operates a first set of cylinders in compression release mode and a second set in motoring mode, initiating power mode upon deactivation demand to quickly reduce negative crankshaft torque, allowing efficient deactivation across various conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If compression release engine brake is activated, then braking torque is increased, but deactivation time becomes excessively long

Engineering Contradiction:

Improvebraking torqueVSAvoiddeactivation time

Core Design Contradiction:

ForceVSDuration of action of moving object

Solution Approach 1:

The invention divides the cylinders into a first set operating in compression release mode and a second set operating in power mode. This segmentation allows independent control of different cylinder groups, enabling the second set to compensate for braking torque during deactivation of the first set, thereby reducing overall deactivation time.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The second set of cylinders is pre-configured to operate in power mode and is ready to immediately compensate for braking torque when the first set needs to deactivate. This preliminary preparation of the second set eliminates the delay associated with transitioning from compression release to motoring mode, significantly reducing deactivation time.

Inventive Principle:

Principle #10Preliminary action

2Device complexity

If compression release engine brake is used, then auxiliary braking requirement is reduced, but deactivation speed is insufficient for anti-lock braking system functionality

Engineering Contradiction:

Improveauxiliary braking systemVSAvoiddeactivation speed

Core Design Contradiction:

Device complexityVSSpeed

Solution Approach 1:

By segmenting cylinders into two independently controllable sets, the system can quickly switch between braking and power modes without transitioning individual cylinders through intermediate states. The second set can immediately provide power mode operation to counteract braking torque, achieving fast deactivation speed comparable to hydraulic retarders.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The control system dynamically switches between compression release mode and power mode based on real-time braking demands. The second set of cylinders can be rapidly transitioned from motoring to power mode and back, providing dynamic response capability that meets anti-lock braking system requirements while eliminating the need for auxiliary braking systems.

Inventive Principle:

Principle #15Dynamics

3Reliability

If compression release mode is deactivated, then normal operation is restored, but negative crankshaft torque reduction is delayed

Engineering Contradiction:

Improveoperation stabilityVSAvoidtorque reduction time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The second set of cylinders is maintained in power mode as a preliminary preparation to immediately compensate for negative crankshaft torque when compression release mode deactivates. This eliminates the torque gap that normally occurs during mode transition, reducing torque reduction time while maintaining operational stability through coordinated cylinder sets.

Inventive Principle:

Principle #10Preliminary 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

Enables quick reduction of negative crankshaft torque, improves driving feel, avoids wheel slip, and meets legislative requirements without needing additional brakes, enhancing safety and efficiency.

Implementation Method 1

operating a first set of cylinders of the plurality of cylinders in a compression release mode

Methodology Applied

Scientific EffectCompression release: Compression

Implementation Method 2

initiating operation of a power mode of the second set of cylinders of the plurality of cylinders upon receipt of a compression release mode deactivation demand

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentEP4357597B1Method of operating a combustion engine, computer program, computer-readable medium, control arrangement, combustion engine, and vehicle

Publication Date: 2025.10.01 SCANIA CV AB

Figure 1~2
Figure 3
Figure 4~6

AI summary

A method (100) of operating an internal combustion engine (1) is disclosed, the internal combustion engine (1) comprising a plurality of cylinders (c1 - c5). The method (100) comprises the steps of operating (110) a first set (s1) of cylinders (c1 - c3) in a compression release mode, operating (120) a second set (s2) of cylinders (c4, c5) in a motoring mode, and initiating (130) operation of a power mode of the second set (s2) of cylinders (c4, c5) upon receipt of a compression release mode deactivation demand (Cbd). The present disclosure further relates to a computer program, a computer-readable medium (200), a control arrangement (21), an internal combustion engine (1), and a vehicle (2).