In-Vehicle Temperature Control Bypass for Cabin Heating

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Solution Overview

Problem

The heating capacity of the heater core in an in-vehicle temperature control system is reduced due to the cold heat medium remaining in the pipe between the internal combustion engine and the heater core, and the temporary use of high-temperature heat medium from the condenser before the engine-heated medium is utilized, leading to inefficient heating.

Innovation Solution

An in-vehicle temperature control system with a thermal circuit and a distribution state switching mechanism that allows the heat medium to bypass the heater core when heated by the internal combustion engine, using a second heating unit like the condenser to preheat the medium, ensuring consistent heating capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the heat medium pipe between the internal combustion engine and the heater core is elongated due to design requirements, then the engine and heater core can be mounted at required positions, but the cold heat medium remaining in the pipe flows into the heater core, reducing heating capacity

Engineering Contradiction:
Improvemounting flexibilityVSAvoidheat medium temperature at heater core inlet
Core Design Contradiction:
Ease of manufactureVSTemperature

Solution Approach 1:

The system performs preliminary heating by circulating heat medium through the engine cooling circuit before it reaches the heater core. The control device activates the water pump to circulate heat medium through the engine first, preheating it in the cooling circuit, so that when it enters the heater core, the heating capacity is maintained despite the long pipe distance.

Inventive Principle:
Principle #10Preliminary action

2Loss of time

If high temperature heat medium from the condenser is supplied to the heater core before engine-heated medium is utilized, then heating can start earlier, but when engine-heated medium flow is started, cold heat medium flows into the heater core temporarily, causing heating capacity to decrease

Engineering Contradiction:
Improveheating start timeVSAvoidheat medium temperature at heater core inlet
Core Design Contradiction:
Loss of timeVSTemperature

Solution Approach 1:

The system maintains continuous heating action by seamlessly switching between heat sources. When the water pump starts circulating engine-heated medium, the control device ensures the three-way valve transitions smoothly to mix or replace the condenser-heated medium with engine-heated medium, preventing any interruption or temperature drop in the heater core.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The three-way valve acts as an intermediary device that mixes heat medium from different sources (condenser and engine cooling circuit). This allows smooth transition between heat sources, preventing the temporary temperature drop that would occur if switching directly from condenser-heated to engine-heated medium.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If a bypass flow path is provided in parallel with the heater core, then heat medium can bypass the heater core when not needed, but the system complexity increases

Engineering Contradiction:
Improveheat medium flow control flexibilityVSAvoidthermal circuit configuration
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The bypass flow path serves multiple functions: it allows heat medium to bypass the heater core when heating is not needed, provides an alternative flow route during different operating conditions, and enables flexible control of heat distribution. This multi-functionality justifies the additional circuit complexity.

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

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 solution maintains the heating capacity of the heater core by ensuring the heat medium is consistently heated before entering the core, even during engine warm-up, thereby improving cabin heating efficiency.

Implementation Method 1

a heater core used to heat an inside of a vehicle cabin using heat of a heat medium

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

a first heating unit that heats the heat medium using exhaust heat of an internal combustion engine

Methodology Applied
Scientific EffectExhaust heat transfer: Heat Exchanger

Implementation Method 3

a thermal circuit configured to circulate the heat medium between the heater core and the first heating unit

Methodology Applied
Scientific EffectFluid circulation: Convection

Data Source

PatentEP3878670B1In-vehicle temperature control system
Publication Date: 2023.08.02 TOYOTA JIDOSHA KK
  • EP3878670B1 patent drawingFigure 1
  • EP3878670B1 patent drawingFigure 2
  • EP3878670B1 patent drawingFigure 3

AI summary

An in-vehicle temperature control system (1) includes: a heater core (43) used to heat an inside of a vehicle cabin using heat of a heat medium; a first heating unit (52) that heats the heat medium using exhaust heat of an internal combustion engine (110); a thermal circuit configured to circulate the heat medium between the heater core (43) and the first heating unit (52); a distribution state switching mechanism (44, 45) that switches a distribution state of the heat medium between a first distribution state and a second distribution state; and a control device (6) that controls the distribution state switching mechanism (44, 45), wherein: the thermal circuit includes a bypass flow path (4f) disposed in parallel with the heater core (43).