Coupled Simulations of Cooling and Engine Systems for Unsteady Analysis of the Benefits of Thermal Engine Encapsulation
Licentiatavhandling, 2015

A well-designed engine encapsulation can extend engine cool-down time significantly - on the order of 500 - 700%. This is expected to have a sensitive influence on the fuel consumption due to the increased probability for high oil temperatures at the following engine start, reduced length of the initial warm-up period and consequently, reduced friction losses. This work aims to set up and develop a simulation platform for investigations of the potential effect of thermal engine encapsulation on fuel consumption of commercial and passenger vehicles. It documents the development and validation of the methods and tools used for this purpose, and apply them to estimate the effect of various initial oil temperatures on the fuel consumption of a commercial vehicle during a cold start drive cycle. Presented is a comprehensive 1D unsteady model verified against experimental data and supported with parallel 3D simulations. The model contains predictive representations of engine, cooling system, oil circuit and utilizes a temperature dependent model of engine friction losses. A number of steady-state and transient simulations are performed for a 13L Volvo FM commercial vehicle and results are compared with physical measurements. The developed 1D and 3D methodologies were validated and achieved satisfactory accuracy both in steady and unsteady mode of operation. Predictions of oil sump temperature development were compared to measured values to conclude that the model is fit for further use in a temperature dependent friction model. As a last step all models were unified to perform a complete vehicle simulation of a cold start drive cycle at different initial oil temperatures in order to evaluate the influence of reduced warm-up phase on fuel consumption. The simulations indicated that there is a potential of up to approx. 3% decrease of fuel consumption as a result of increased initial engine temperatures.

Oil system

Cooling system

Drive cycle

CFD simulations

Fuel consumption

Engine encapsulation

1D simulations

VDL Hörsalsvägen 7 A, Göteborg
Opponent: Dr-Ing. Burkhard Hupertz

Författare

Blago Minovski

Chalmers, Tillämpad mekanik, Fordonsteknik och autonoma system

Study of Software Integration for Transient Simulation of Future Cooling System for Heavy Truck Application

SAE International, SAE Technical Paper 2014-01-0653, 2014, doi:10.4271/2014-01-0653.,; (2014)

Paper i proceeding

A 1D Method for Transient Simulations of Cooling Systems with Non-Uniform Temperature and Flow Boundaries Extracted from a 3D CFD Solution

SAE Technical Papers: SAE 2015 World Congress and Exhibition; Cobo CenterDetroit; United States; 21 April 2015 through 23 April 2015,; (2015)

Paper i proceeding

Drivkrafter

Hållbar utveckling

Styrkeområden

Transport

Energi

Ämneskategorier

Farkostteknik

Strömningsmekanik och akustik

VDL Hörsalsvägen 7 A, Göteborg

Opponent: Dr-Ing. Burkhard Hupertz