Supplemental Coolant Heater Load for Low-Load Gensets

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Solution Overview

Problem

Existing gensets face challenges in maintaining engine load at low demand conditions, leading to ineffective operation of exhaust aftertreatment systems and slow engine warm-up, with current solutions like belt-driven water pumps and resistive load banks being inefficient or costly.

Innovation Solution

A genset equipped with an electrically powered supplemental load device (SLD) that increases alternator and engine load through an electric engine coolant heater, controlled by a monitoring system to activate when engine load falls below a threshold.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the engine is sized to meet the highest-rated electrical power demand, then the alternator can operate at constant speed, but the engine experiences very low demand during low electrical power demand periods

Engineering Contradiction:

Improvealternator operationVSAvoidengine load

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

An electric heater is introduced as an intermediary load device that can be activated to impose additional electrical load on the alternator when the engine operates at low load conditions. This mediator component allows the engine to maintain adequate load levels without requiring oversizing, by providing supplemental power demand through the heater element that converts excess electrical capacity into useful thermal energy.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Use of energy by moving object

If a belt driven water pump with electromagnetic clutch is used to increase engine load, then the engine load increases, but the clutch experiences increased wear and tear due to engagement at high speeds

Engineering Contradiction:

Improveengine loadVSAvoidclutch lifespan

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The mechanical belt-driven water pump system with electromagnetic clutch is replaced with an electrically powered heater system. This substitution eliminates the mechanical coupling and clutch engagement issues by using an electrical load imposed directly on the alternator, thereby removing the wear and reliability problems associated with high-speed clutch operation while still achieving the goal of increasing engine load.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Use of energy by moving object

If a resistive load bank with transformers is used to maintain engine load, then the engine load is maintained, but the system generates substantial heat and requires expensive transformers

Engineering Contradiction:

Improveengine loadVSAvoidheat generation

Core Design Contradiction:

Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The electric heater serves a dual function: it imposes the necessary electrical load on the alternator to maintain engine load, and simultaneously provides useful heating output. This self-service approach eliminates the waste heat problem of traditional resistive load banks by converting the harmful thermal byproduct into a useful output, thereby removing the need for expensive transformers and heat dissipation systems.

Inventive Principle:

Principle #25Self-service

4Reliability

If the electromagnetic clutch is engaged at the lowest reasonable RPM, then clutch wear is reduced, but the alternator output is reduced

Engineering Contradiction:

Improveclutch lifespanVSAvoidalternator output

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The entire mechanical clutch engagement system is replaced with an electrical heating load system. This substitution allows the alternator to operate continuously at optimal speed and power output without the need for mechanical clutch engagement at varying RPM levels. The electrical heater can be activated or deactivated independently of engine speed, eliminating the trade-off between clutch wear and alternator output.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

The SLD effectively maintains engine load above a threshold, ensuring efficient operation of exhaust aftertreatment systems and accelerating engine warm-up, reducing wear and tear on components while avoiding excessive heat generation.

Implementation Method 1

A genset equipped with an electrically powered supplemental load device (SLD) that increases alternator and engine load through an electric engine coolant heater

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS12529332B1Genset with supplementary load device

Publication Date: 2026.01.20 WACKER NEUSON CORP

AI summary

A genset is equipped with an electrically powered supplemental load device (SLD) that controls an aspect of engine operation. A controller controls the SLD to increase electrical load on the alternator and, thus, increase mechanical load on the engine, if monitored engine load is beneath a threshold. The SLD may comprise an electric engine coolant heater. The engine may be a diesel engine equipped with an exhaust aftertreatment system (ATS). In this case, the load threshold may be one below which at least one component of the ATS does not operate effectively. Engine load may be monitored indirectly by monitoring electrical load on the alternator. If so, the engine load may be considered to be proportional to alternator electrical load. Also disclosed is a method of operating a genset.