Radial Expander in Engine Cooling Circuit for Heat Recovery

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing internal combustion engine cooling systems face inefficiencies in utilizing heat energy, particularly in varying vehicle interior heating needs and seasonal demands, with existing solutions requiring significant structural space and complex configurations.

Innovation Solution

A supercharged internal combustion engine with a cooling circuit that partially converts working medium into vapor or gas, utilizing a two-stroke radial piston engine as an expander unit connected to the output shaft, allowing for efficient conversion of kinetic energy within a compact space, with the radial engine arranged between the internal combustion engine and fan wheel for space-saving integration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a conventional cooling system is used to convert heat energy, then the system can operate, but it requires significant structural space and complex configurations

Engineering Contradiction:
Improveheat energy utilizationVSAvoidsystem configuration
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent combines the cooling circuit and expander unit into an integrated system where the cooling medium serves dual purposes: cooling the engine and driving the expander. The cooling circuit is configured to directly feed vaporized cooling medium to the expander unit, eliminating the need for separate heat recovery components and reducing overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cooling medium performs multiple functions within the system: it cools the internal combustion engine, absorbs heat energy, vaporizes to provide expansion work, and drives the expander unit. This multi-functionality reduces the need for separate systems and components, thereby reducing structural space and configuration complexity.

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

2Use of energy by moving object

If a conventional cooling system is used to convert heat energy, then the system can operate, but it requires significant structural space

Engineering Contradiction:
Improveheat energy utilizationVSAvoidstructural space
Core Design Contradiction:
Use of energy by moving objectVSVolume of moving object

Solution Approach 1:

The expander unit is positioned to utilize space within or adjacent to the existing engine structure. The cooling circuit components are integrated into the engine block or surrounding structure, allowing the expander unit to be nested within the overall engine assembly rather than requiring separate external space.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

By merging the cooling system and power generation functions into a single integrated system, the patent eliminates the need for separate heat exchangers, steam generators, and expander units that would occupy additional space. The compact integration reduces the overall volume required for heat energy conversion.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of operation

If heat is used to heat the vehicle interior, then occupant comfort is improved, but the heat required varies and rarely corresponds to the power output of the combustion engine

Engineering Contradiction:
Improveheat utilization flexibilityVSAvoidexcess heat waste
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The system changes the state parameter of the cooling medium from liquid to vapor through phase transition, enabling it to expand and drive the expander unit. This parameter change allows the system to convert excess heat energy into mechanical work, providing flexible energy utilization that adapts to varying engine output conditions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent converts the harmful waste heat that would otherwise be lost to the environment into useful mechanical energy by using it to vaporize the cooling medium and drive the expander unit. This transforms the excess heat problem into a beneficial power source, reducing energy waste while maintaining operational flexibility.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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

This configuration enables efficient conversion of heat energy into kinetic energy, achieving up to 40 kW output with a compact design, optimizing engine efficiency and reducing structural requirements while allowing for both drive and braking modes.

Implementation Method 1

a cooling circuit in which a working medium is circulated, which is at least partially converted into a vapor or gaseous state of aggregation

Methodology Applied
Scientific EffectPhase transition (liquid to vapor): Phase Change

Implementation Method 2

in which the at least partially vaporous or gaseous working medium is expanded and the kinetic energy of the vapor or gas is converted into kinetic energy

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP1870575B1Charged combustion engine with an expander unit in a heat recovery loop
Publication Date: 2019.05.08 MAN TRUCK & BUS SE
  • EP1870575B1 patent drawingFigure 1
  • EP1870575B1 patent drawingFigure 2
  • EP1870575B1 patent drawingFigure 3

AI summary

The engine (1) has a cooling circuit, in which a medium that is partially transferred into a steam or gaseous aggregation state is recycled. An expander unit is in effective connection with a driven shaft of the engine over a power train for production of kinetic energy. The expander unit is implemented as a two-stroke reciprocating engine, which is directly or indirectly connected with the driven shaft of the engine over the power train. The two-stroke reciprocating engine is arranged within the housing surrounding the internal combustion engine, and is implemented as a radial engine (2).