TERU Communication Interface for Engine-Off Refrigeration Control

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Solution Overview

Problem

Existing transport refrigeration units (TERUs) require a vehicle engine to be running for power and control, leading to unnecessary energy consumption and inefficiencies, particularly in systems without dedicated engines.

Innovation Solution

A controller with direct data and power connections to vehicle devices, such as a temperature sensor, allows independent operation without intermediate components like PTOs, relying on vehicle safety logic for engine start-up, enabling a sleep mode for reduced power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the vehicle engine is kept running to power the TERU and control systems, then the refrigeration unit can operate continuously, but energy consumption increases and operational efficiency decreases

Engineering Contradiction:
Improvecontinuous operation capabilityVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system dynamically transitions between different operational states: the controller can wake up the engine when refrigeration is needed and allow it to sleep when not needed. This dynamic state change enables the system to maintain reliability when required while minimizing energy consumption during idle periods.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The temperature sensor continuously monitors the refrigerated compartment and autonomously determines when refrigeration is needed, triggering engine startup only when necessary. This self-service approach eliminates the need for continuous engine operation while maintaining temperature control reliability.

Inventive Principle:
Principle #25Self-service

2Power

If intermediate components like PTO are used to connect the engine to the TERU, then power transmission is established, but system complexity increases and control efficiency decreases

Engineering Contradiction:
Improvepower transmission capabilityVSAvoidsystem complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The controller is extracted from the PTO integration and given direct connections to both the engine and temperature sensor. This separation eliminates the need for PTO as an intermediate component, reducing system complexity while maintaining full power transmission capability through direct engine-to-controller linkage.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The controller serves as a new intermediary that directly mediates between the engine and temperature sensor, replacing the PTO's intermediary role. This new mediator simplifies the power transmission path while enabling more efficient control signals to flow directly between components.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Extent of automation

If the controller is integrated within the PTO, then control functions are consolidated, but the engine must run for control signals to be transmitted, reducing operational flexibility

Engineering Contradiction:
Improvecontrol integration levelVSAvoidoperational flexibility
Core Design Contradiction:
Extent of automationVSAdaptability or versatility

Solution Approach 1:

The control system is segmented into independent components: the temperature sensor, controller, and engine are separated but connected through direct interfaces. This segmentation allows the controller to operate independently of PTO, enabling the engine to remain off while control functions are fully available when needed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The controller is prepared with direct connections to both the engine and temperature sensor in advance, eliminating the need for PTO-based control signal transmission. This preliminary setup enables the controller to immediately activate the engine when temperature thresholds are exceeded, without requiring PTO to be operational first.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3805550B1Electrical communication interface for a transport engineless refrigeration unit
Publication Date: 2026.03.18 CARRIER CORP
  • EP3805550B1 patent drawingFigure 1
  • EP3805550B1 patent drawingFigure 2
  • EP3805550B1 patent drawingFigure 3

AI summary

A control system (300) for a transport engineless refrigeration unit (301), the control system comprising: a controller (302) for communication between a vehicle (307) and a plurality of vehicle devices, the controller comprising: a vehicle data connection (306) for transmitting data to and from a vehicle; a vehicle engine on/off connection (308) for triggering start-up of the vehicle engine; a plurality of device data connections (314), wherein each device data connection transmits data to and from at least one device external to the controller; and a device power connection (313), wherein the device power connection supplies power from the controller to at least one device external to the controller.