Heat retention analysis with thermal encapsulation of powertrain under natural soak environment

This paper investigates high fatality modelling of vehicle heat transfer process during natural soak environment and heat retention benefits with powertrain encapsulations. A coupled computer-aided-engineering (CAE) method utilising 3D computational-fluids-dynamics (CFD) and transient thermal modelling was applied to solve buoyancy-driven convection, thermal radiation and conduction heat transfer of vehicle structure and fluids within. Two vehicle models with different encapsulation layouts were studied. One has engine-mounted-encapsulation (EME) and the other has additional vehicle-mounted-encapsulation (VME). Coupled transient heat transfer simulations were carried out for the two vehicle models to simulate their cool-down behaviours of 9 h static soak. The key fluids temperatures’ cool-down trajectories were obtained and correlated well with vehicle test data. Increased end temperatures were seen for both coolant and oils of the VME model. This provides potential benefits towards CO2 emissions reduction and fuel savings. The air paths and thermal leakages with both encapsulations were visualised. Reduced leakage pathways were found in the VME design in comparison with the EME design. This demonstrated the capability of embedded CAE encapsulation heat retention modelling for evaluating encapsulation designs to reduce fuel consumption and emissions in a timely and robust manner, aiding the development of low-carbon transport technologies

Integrated modelling for vehicles thermal energy management

Intelligent thermal and energy management can help deliver optimized engineering solutions for next-generation low-carbon vehicles, mitigating environmental pollution and minimising real-world energy consumption to deliver better fuel economy and electric range as well as drive comfort. Different application specific modelling environments are used in modern vehicle developments across the vehicle development cycle. In this paper, a holistic approach towards assessment of thermal and fluid interactions within an automobile was taken, to simulate the performance, heat flux, thermodynamic and energy efficiency of the vehicle system. The overall system consists of vehicle propulsion system, cabin climate system, cooling system, electrical system, chassis and control systems. The powertrain subsystem models were developed to evaluate friction losses, fuel consumption, emissions, as well as battery utilization over legislative drive cycles. The heating, ventilation and air-conditioning (HVAC) and cabin models were developed to assess additional fuel consumption and energy optimization from cabin thermal comfort. A co-simulation platform is developed and simulated in this paper for subsequent thermal control strategy development. This paper discusses the model development and software integration of different physical domains. The developed integrated virtual model provides a tool for system level design and analysis and evaluation of fuel consumption and emissions

Co-simulation methods for holistic vehicle design: A comparison

Vehicle development involves the design and integration of subsystems of different domains to meet performance, efficiency, and emissions targets set during the initial developmental stages. Before a physical prototype of a vehicle or vehicle powertrain is tested, engineers build and test virtual prototypes of the design(s) on multiple stages throughout the development cycle. In addition, controllers and physical prototypes of subsystems are tested under simulated signals before a physical prototype of the vehicle is available. Different departments within an automotive company tend to use different modelling and simulation tools specific to the needs of their specific engineering discipline. While this makes sense considering the development of the said system, subsystem, or component, modern holistic vehicle engineering requires the constituent parts to operate in synergy with one-another in order to ensure vehicle-level optimal performance. Due to the above, integrated simulation of the models developed in different environments is necessary. While a large volume of existing cosimulation related publications aimed towards engineering software developers, user-oriented publications on the characteristics of integration methods are very limited. This paper reviews the current trends in model integration methods applied within the automotive industry. The reviewed model integration methods are evaluated and compared with respect to an array of criteria such as required workflow, software requirements, numerical results, and simulation speed by means of setting up and carrying out simulations on a set of different model integration case studies. The results of this evaluation constitute a comparative analysis of the suitability of each integration method for different automotive design applications. This comparison is aimed towards the end-users of simulation tools, who in the process of setting up a holistic high-level vehicle model, may have to select the most suitable among an array of available model integration techniques, given the application and the set of selection criteria

Evaluation of in-cylinder endoscopic two-colour soot pyrometry of diesel combustion

Flame temperature and soot concentration imaging was performed using endoscopic two-colour (2C) soot pyrometry to investigate the characteristics of in-cylinder diesel engine combustion processes and pro- vide validation data for engine simulation and design. To appropriately interpret the 2C image results, this paper focuses on the uncertainty and challenges of the technique, the line-of-sight nature of the measurement and presents comparable information for validation exercises. A line-of-sight flame light intensity model was created to explore how the temperature T and soot concentration KL measured by the 2C technique can relate to non-uniform flame temperature and soot distributions. It was found that T and KL measured from the 2C technique were likely to relate differently to the actual distribution de- pending on where in the flame the measurement was taken and on assumptions made about the flame spatial structure. Assessment has been made of the range of the maximum and minimum flame tem- peratures (assumed to correspond to reaction zone temperature and flame centreline respectively) that are consistent with measured temperature T and soot concentration KL . The analysis of uncertainties, flame temperature and soot distribution along the line-of-sight, and image averaging allows for better quantitative comparison of 2C soot pyrometry images to CFD simulation, which increases confidence in simulation-driven engine development.</p