PHEV Coolant Routing for Cold-Weather EV Mode

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Solution Overview

Problem

Plug-in hybrid electric vehicles struggle to operate in pure electric drive mode at ambient temperatures below 15° C due to insufficient heating from the fuel-operated heater, and experience high climate system electric power consumption at temperatures above 25° C.

Innovation Solution

A system with a three-way valve that bypasses the internal combustion engine, allowing the fuel-operated heater to provide heat directly to the passenger compartment and HVAC system, supplemented by an electrical pump for coolant circulation when the engine is not running, and a mechanical pump when it is, to optimize thermal power distribution and reduce energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the vehicle runs in pure electric drive mode at ambient temperatures below 15° C without bypassing the internal combustion engine, then the fuel operated heater cannot provide sufficient heat to warm up the passenger compartment and meet internal combustion engine thermal targets, but if the internal combustion engine is not bypassed, the engine coolant will cool down the coolant to such an extent that the fuel operated heater would never alone be able to handle the passenger compartment heating

Engineering Contradiction:

Improvepassenger compartment temperatureVSAvoidfuel economy

Core Design Contradiction:

TemperatureVSUse of energy by moving object

Solution Approach 1:

The coolant circuit is segmented into multiple paths using a three-way valve, allowing selective routing of coolant flow. This enables the system to separate the heating function for the passenger compartment from the internal combustion engine cooling function, permitting the fuel operated heater to warm the cabin without being cooled by the engine while maintaining engine thermal targets through controlled coolant circulation.

Inventive Principle:

Principle #1Segmentation

2Temperature

If the fuel operated heater is dimensioned to alone manage passenger compartment heating at cold ambient temperatures, then heating capability is sufficient, but the device size becomes unrealistic to incorporate into the vehicle and energy consumption increases requiring large amounts of energy to run

Engineering Contradiction:

Improvepassenger compartment heating capabilityVSAvoidfuel consumption

Core Design Contradiction:

TemperatureVSQuantity of substance

Solution Approach 1:

The system merges the heating capabilities of both the fuel operated heater and the internal combustion engine by allowing coolant to bypass the engine and flow directly to the HVAC heater. This combination enables the smaller fuel operated heater to effectively manage passenger compartment heating without requiring excessive size or energy consumption, as the engine can contribute to heating when available.

Inventive Principle:

Principle #5Merging (Combining)

3Loss of energy

If the internal combustion engine is not bypassed at and above 25° C ambient temperature, then engine cooling is maintained, but the electrical power needed to fulfil the climate system thermal targets increases

Engineering Contradiction:

Improveclimate system electric power consumptionVSAvoidengine coolant temperature

Core Design Contradiction:

Loss of energyVSTemperature

Solution Approach 1:

The three-way valve dynamically adjusts coolant flow routing based on ambient temperature and engine operating conditions. At and above 25° C ambient temperature, the valve can fully bypass the cabin heater to minimize electrical power consumption for climate control, while still maintaining engine coolant temperature through controlled circulation paths. This dynamic adjustment optimizes energy efficiency across different operating conditions.

Inventive Principle:

Principle #15Dynamics

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 extended pure electric drive feasibility down to -40° C while minimizing climate system electric power consumption at higher temperatures, improving fuel economy and reducing environmental impact.

Implementation Method 1

a fuel operated heater (4) having a coolant inlet (3) and a coolant outlet (5)

Methodology Applied

Scientific EffectCombustion heating: Combustion

Implementation Method 2

an HVAC heater (7) having a coolant inlet (6) and a coolant outlet (8)

Methodology Applied

Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 3

a temperature sensor (10) arranged at the coolant outlet (2) of the internal combustion engine (1) and a temperature sensor (11) arranged at the coolant outlet (5) of the fuel operated heater (4)

Methodology Applied

Scientific EffectThermal detection: Thermocouple

Data Source

PatentUS9649910B2Running a PHEV in EV mode under cold conditions

Publication Date: 2017.05.16 VOLVO CAR CORP

AI summary

A plug-in hybrid electric vehicle has an internal combustion engine with a coolant outlet connected to a coolant inlet of a fuel operated heater and wherein a coolant outlet of the fuel operated heater is connected to a coolant inlet of an HVAC heater, a coolant outlet of the HVAC heater further being connected to a coolant inlet of the internal combustion engine. The vehicle also has a temperature sensor at the coolant outlet of the internal combustion engine and a temperature sensor at the coolant outlet of the fuel operated heater. The vehicle has a three way valve arranged between the coolant outlet of the HVAC heater and the coolant inlet of the internal combustion engine such that there is a connection between the coolant outlet of the HVAC heater and the coolant inlet of the fuel operated heater, the connection bypassing the internal combustion engine.