Heat Exchanger Control Apparatus Flow Rate Management

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Solution Overview

Problem

The existing control apparatus for heat exchanging systems often results in a decrease in core flow rate when the engine water passage is connected to the heater water passage, leading to reduced air temperature in vehicles, causing discomfort to occupants.

Innovation Solution

The control apparatus includes an electronic control unit that adjusts the duty ratios of the heater and engine pumps to maintain the core flow rate at the requested level by connecting the engine water passage to the heater water passage, increasing the engine pump duty ratio and decreasing the heater pump duty ratio, thereby preventing a decrease in core flow rate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the engine water passage is connected to the heater water passage, then the heater core can be heated by heat exchanging water from the engine, but the core flow rate decreases below the requested core flow rate

Engineering Contradiction:
Improveheater core temperatureVSAvoidcore flow rate
Core Design Contradiction:
TemperatureVSProductivity

Solution Approach 1:

The control apparatus increases the engine pump duty ratio before connecting the engine water passage to the heater water passage. This preliminary action ensures that sufficient heat exchanging water is available in the engine water passage to maintain the requested core flow rate after connection, preventing the flow rate decrease that would otherwise occur when the passages are connected.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If the engine water passage is connected to the heater water passage, then heat exchanging water can be supplied to the heater core, but the flow resistance of the heat exchanging system changes causing core flow rate to decrease

Engineering Contradiction:
Improvesystem connectivityVSAvoidcore flow rate
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The control apparatus dynamically adjusts the engine pump duty ratio based on the connection state of the water passages. When the engine water passage is connected to the heater water passage, the engine pump duty ratio is increased to compensate for the changed flow resistance, thereby maintaining the core flow rate at the requested level despite the system connectivity change.

Inventive Principle:
Principle #15Dynamics

3Use of energy by moving object

If the heater pump duty ratio is decreased after connection, then energy consumption is reduced, but core flow rate may decrease below requested level

Engineering Contradiction:
Improveheater pump energy consumptionVSAvoidcore flow rate
Core Design Contradiction:
Use of energy by moving objectVSProductivity

Solution Approach 1:

The control apparatus monitors the core flow rate and adjusts the heater pump duty ratio accordingly. After connecting the engine water passage to the heater water passage, the system decreases the heater pump duty ratio to reduce energy consumption, but only after ensuring that the core flow rate remains at or above the requested level through this feedback control mechanism.

Inventive Principle:
Principle #23Feedback

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 ensures that the core flow rate remains at the requested level, maintaining the desired air temperature in vehicles and preventing discomfort, while also preventing overheating of the exhaust heat recovery device.

Implementation Method 1

a heater core heating system for heating a heater core for heating air supplied to an interior of a vehicle by heat exchanging water

Methodology Applied
Scientific EffectHeat exchange: Convection

Implementation Method 2

an engine cooling system for cooling an internal combustion engine by the heat exchanging water

Methodology Applied
Scientific EffectHeat exchange: Convection

Data Source

PatentEP3428421B1Control apparatus of heat exchanging system
Publication Date: 2021.08.25 TOYOTA JIDOSHA KK
  • EP3428421B1 patent drawingFigure 1
  • EP3428421B1 patent drawingFigure 2
  • EP3428421B1 patent drawingFigure 3

AI summary

A control apparatus of a heat exchanging system according to the invention executes a control for activating a connection system (60) to connect an engine water passage (16, 11W, 17, 18, 12W, 19) to a heater water passage (40, 33W, 41, 31W, 42, 43, 34W, 44) and a control for increasing an engine pump duty ratio (DE), and then executes a control for decreasing a heater pump duty ratio (DH) when the control for decreasing the heater pump duty ratio (DH) and the control for increasing the engine pump duty ratio (DE) are requested to be executed in order to control a core flow rate (Vhc) to a requested core flow rate (Vhc_req) and an engine flow rate (Veng) to a requested engine flow rate (Veng_req) after the engine water passage is connected to the heater water passage by the connection system (60).