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Fuel efficiency and torque performance are two major challenges for highly downsized turbocharged engines. However, the inherent characteristics of the turbocharged SI engine such as negative PMEP, knock sensitivity and poor transient performance significantly limit its maximum potential. Conventional ways of improving the problems above normally concentrate solely on the engine side or turbocharger side leaving the exhaust manifold in between ignored. This paper investigates this neglected area by highlighting a novel means of gas exchange process. Divided Exhaust Period (DEP) is an alternative way of accomplishing the gas exchange process in turbocharged engines. The DEP concept engine features two exhaust valves but with separated function. The blow-down valve acts like a traditional turbocharged exhaust valve to evacuate the first portion of the exhaust gas to the turbine.

The work presented here seeks to compare different means of providing scavenging systems for an automotive 2-stroke engine. It follows on from previous work solely investigating uniflow scavenging systems, and aims to provide context for the results discovered there as well as to assess the benefits of a new scavenging system: the reverse-uniflow sleeve-valve. For the study the general performance of the engine was taken to be suitable to power a medium-duty truck, and all of the concepts discussed here were compared in terms of indicated fuel consumption for the same cylinder swept volume using a one-dimensional engine simulation package. In order to investigate the sleeve-valve designs layout drawings and analysis of the Rolls-Royce Crecy-type sleeve had to be undertaken.

Current developments in automotive industry such as hybrid powertrains and the continuously increasing demands on emission control systems, are pushing complexity still further. Validation of such systems lead to a huge amount of test cases and hence extreme testing efforts on the road. At the same time the pressure to reduce costs and minimize development time is creating challenging boundaries on development teams. Therefore, it is of utmost importance to utilize testing and validation prototypes in the most efficient way. It is necessary to apply high levels of instrumentation and collect as much data as possible. And a streamlined data pipeline allows the fleet managers to get new insights from the raw data and control the validation vehicles as well as the development team in the most efficient way. In this paper we will demonstrate a data-driven approach for validation testing.

This paper presents a novel battery degradation model based on empirical data from the Racing Green Endurance project. Using the rainflow-counting algorithm, battery charge and discharge data from an electric vehicle has been studied in order to establish more reliable and more accurate predictions for capacity and power fade of automotive traction batteries than those currently available. It is shown that for the particular lithium-iron phosphate (LiFePO₄) batteries, capacity fade is 5.8% after 87 cycles. After 3,000 cycles it is estimated to be 32%. Both capacity and power fade strongly depend on cumulative energy throughput, maximum C-rate as well as temperature.

A comprehensive general purpose engine simulation model has been successfully developed. This paper reports on an investigation undertaken to compare the accuracy and computational efficiency of four alternative methods for modelling the gas flow and performance in internal combustion engines. The comparison is based on the filling-and-emptying method, the acoustic method, the Lax-Wendroff two-stage difference method and the Harten-Lax-Leer upstream method, using a unified treatment for the boundary conditions. The filling-and-emptying method is the quickest method among these four methods, giving performance predictions with reasonably good accuracy, and is suitable for simulating engines using not highly tuned gas exchange systems. Based on the linearized Euler equations, the acoustic method is capable of describing time-varying pressure distributions along a pipe.

Modeling plume interaction and collapse for direct-injection gasoline sprays is important because of its impact on fuel-air mixing and engine performance. Nevertheless, the aerodynamic interaction between plumes and the complicated two-phase coupling of the evaporating spray has shown to be notoriously difficult to predict. With the availability of high-speed (100 kHz) Particle Image Velocimetry (PIV) experimental data, we compare velocity field predictions between plumes to observe the full temporal evolution leading up to plume merging and complete spray collapse. The target “Spray G” operating conditions of the Engine Combustion Network (ECN) is the focus of the work, including parametric variations in ambient gas temperature. We apply both LES and RANS spray models in different CFD platforms, outlining features of the spray that are most critical to model in order to predict the correct aerodynamics and fuel-air mixing.

Driver behaviour can strongly affect fuel consumption, and driver training in eco-driving techniques has been shown to reduce fuel consumption by 10% on average. However the effects of this training can be short-lived, so there is an apparent need for continuous monitoring of driver behaviour. This study presents a driver advisory tool which encourages eco-driving, and its evaluation in the field. The system, developed by Ashwoods Automotive Ltd (UK) and the University of Bath (UK), is aimed at fleet operators of light commercial vehicles, where the driver is typically a company employee. A significant strength of the system is that it has been designed for easy integration with the vehicle CAN-bus, reducing complexity and cost. By considering the Inertial Power Surrogate (speed times acceleration) the core algorithm is able to identify behaviour which is likely to increase fuel consumption.

Internal combustion engines are routinely developed using 1D engine simulation tools. A well-known limitation is the accuracy of the turbocharger compressor and turbine sub-models, which rely on hot gas bench-measured maps to characterize performance. Such discrete map data is inherently too sparse to be used directly in simulation, and so a preprocessing algorithm interpolates and extrapolates the data to generate a wider, more densely populated map. Methods used for compressor map interpolation vary. They may be mathematical or physical in nature, but there is no unified approach, except that they typically operate on input map data in SAE format. For decades it has been common practice for turbocharger suppliers to share performance data with engine OEMs in this form. This paper describes a compressor map interpolation technique based on the nondimensional compressor flow and loading coefficients, instead of SAE-format data.

A new hydraulic cam follower with variable valve timing (VVT) properties is described. Experimental results show that the point of closure of the valve may be delayed as a linear function of engine speed without external control. No other parameter of the valve event is modified by the device. An obvious application is the control of intake valve timing for engines with a wide speed range, where the point of valve closure could be scheduled with engine speed in order to maximise the trapped mass, hence improving the torque curve at low and high speeds. The device is considered for application to the Ford 2.5 litre DI diesel engine, where it may be used to retard inlet valve closure from close to bottom dead centre (BDC) at cranking speed to 50-60 deg after BDC at rated speed.

Trends towards lower vehicle fuel consumption and smaller environmental impact will increase the share of Diesel hybrids and Diesel Range Extended Vehicles (REV). Because of the Diesel engine presence and the ever tightening soot particle emissions, these vehicles will still require soot particle emissions control systems. Ceramic wall-flow monoliths are currently the key players in the Diesel Particulate Filter (DPF) market, offering certain advantages compared to other DPF technologies such as the metal based DPFs. The latter had, in the past, issues with respect to filtration efficiency, available filtration area and, sometimes, their manufacturing cost, the latter factor making them less attractive for most of the conventional Diesel engine powered vehicles. Nevertheless, metal substrate DPFs may find a better position in vehicles like Diesel hybrids and REVs in which high instant power consumption is readily offered enabling electrical filter regeneration.

Automotive embedded systems have become very complex, are strongly integrated, and the safety-criticality and real-time constraints of these systems raise new challenges. The OSEK/VDX standard provides an open-ended architecture for distributed real-time capable units in vehicles. This is supported by the OSEK Implementation Language (OIL), a language aiming at specifying the configuration of these real-time operating systems. The challenge, however, is to ensure consistency of the concept constraints and configurations along the entire product development. The contribution of this paper is to bridge the existing gap between model-driven systems engineering and software engineering for automotive real-time operating systems (RTOS). For this purpose a bidirectional tool bridge has been established based on OSEK OIL exchange format files.

In both the marine and power industries there are now a choice of off-the-shelf condition monitoring systems available that utilise artificial intelligence techniques to analyse engine performance data. These systems are proving to be a valuable aid in optimising performance and reducing down-time by assisting with maintenance planning. These systems rely on careful monitoring of an engine's performance, for instance engine speed, fuelling, boost pressure, turbine inlet pressure, turbocharger speed, and exhaust temperature. With this data, they utilise a variety of interpolation and pattern recognition algorithms to compare it with previously recorded data stored in lookup tables. This paper describes how a neural network approach can be used as a cheap alternative for the analysis of this data, greatly reducing the need for such large lookup tables and complex pattern recognition programs.

Results from numerical computations performed to represent the transient behavior of vaporizing sprays injected into a constant volume chamber and into a High Speed Direct Injection combustion chamber are presented. In order to describe the liquid phase, a new model has been developed from ideas brought forward by recent experimental results (Siebers, 1999) and numerical considerations (Abraham, 1999). The liquid penetration length is given by a 1D model which has been validated on a large number of experiments. In the 3D calculation, break-up, vaporization, drag, collision and coalescence are not modeled. The mass, momentum and energy transfers from the liquid to the gas phase are imposed from the nozzle exit surface to the liquid penetration length. This model enables us to reach time step and grid-independent results. The gas penetrations obtained with the model are checked against experimental results in a constant volume chamber (Verhoeven et al., 1998).

Throttling loss of downsized gasoline engines is significantly smaller than that of naturally aspirated counterparts. However, even the extremely downsized gasoline engine can still suffer a relatively large throttling loss when operating under part load conditions. Various de-throttling concepts have been proposed recently, such as using a FGT or VGT turbine on the intake as a de-throttling mechanism or applying valve throttling to control the charge airflow. Although they all can adjust the mass air flow without a throttle in regular use, an extra component or complicated control strategies have to be adopted. This paper will, for the first time, propose a de-throttling concept in a twin-charged gasoline engine with minimum modification of the existing system. The research engine model which this paper is based on is a 60% downsized 2.0L four cylinder gasoline demonstrator engine with both a supercharger and turbocharger on the intake.

Future legislation, like EURO IV and EURO V or the US 2007 HD regulation will have massive reduction of particulate emission limits. For this beside improvement of engine combustion also exhaust aftertreatment systems are under investigation, like Diesel Particulate Filters (DPF), or Selective Catalytic Reduction (SCR) of Nitrogen Oxides. For all those tasks transient soot emission monitoring is one of the key features. To meet this demand a new device for the on-line measurement of soot emitted by combustion engines has been developed. Based on the photoacoustic principle, which has been optimized for automotive applications and easy use in test cells, the instrument shows a sensitivity of 5μg/m3, which is lower than current particulate immission standards in ambient air, and a time resolution of 1 sec. In the paper first the principles of measurement are shown, and then the specifications and results from measurements of very low soot concentration in the exhaust gas are presented.

Engines equipped with pressure charging systems are more prone to knock partly due the increased intake temperature. Meanwhile, turbocharged engines when operating at high engine speeds and loads cannot fully utilize the exhaust energy as the wastegate is opened to prevent overboost. The turboexpansion concept thus is conceived to reduce the intake temperature by utilizing some otherwise unexploited exhaust energy. This concept can be applied to any turbocharged engines equipped with both a compressor and a turbine-like expander on the intake loop. The turbocharging system is designed to achieve maximum utilization of the exhaust energy, from which the intake charge is over-boosted. After the intercooler, the turbine-like expander expands the over-compressed intake charge to the required plenum pressure and reduces its temperature whilst recovering some energy through the connection to the crankshaft.

The development process of a combustion engine is now a days strongly influenced by future emission regulations which require further reduction in fuel consumption and precise control of combustion process based on Intake air measurement, during engine development. Intake air flow meters clearly differentiate themselves from typical industrial gas flow meters because of their ability to measure extremely dynamic phenomenon of combustion engine. Thus, high internal data acquisition rate, short response time, ability to measure pulsating and reverse flows with lower measurement uncertainty are the factors that ensures the reliability of the results without being affected by ambient influences, sensor contamination or sensor aging. The AVL developed FLOWSONIX™ is based on ultrasonic transit time measuring principle with broad-band Capacitive Ultrasonic Transducer (CUT) characterized by an excellent air impedance matching strongly distinguishes itself by fulfilling all those requirements.

The reduction of particulate emissions limits requires new tools for the tuning of engines and exhaust aftertreatment systems. Time-resolved monitoring of low soot emissions is a key feature for such developments. The paper describes an improved photoacoustic soot sensor, and presents its applications for the characterization of transient exhaust soot emissions before and after Diesel emission after-treatment systems. The detection limit of the unit is around 5 μg/m3 soot, which is two orders of magnitude better than conventional time-resolved transmission measurement. Additionally, a wide dynamic range of four orders of magnitude can be achieved without range switching. The photoacoustic signal is proportional to the soot mass, no significant cross-sensitivities to gaseous absorbers were detected.

Particulate emissions from gasoline direct injection (GDI) engines continue to be a topic of substantial research interest. Forthcoming regulation both in the USA and the EU will further reduce their emission and drive innovation. Substantial research effort is spent undertaking experiments to understand, characterize, and research particle number (PN) emissions from engines and vehicles. Recent advances in computing power, data storage, and understanding of artificial intelligence algorithms now mean that these are becoming an important tool in engine research. In this work a random forest (RF) algorithm is used for the prediction of PN emissions from a highly boosted (up to 32 bar BMEP) GDI engine. Particle size, concentration, and the accumulation mode geometric standard deviation (GSD) are all predicted by the model. The results are analysed and an in depth study on parameter importance is carried out.

A range extended electric vehicle (REEV) has the benefit of zero pipeline emission for most of the daily commute driving using the full electric mode while maintaining the capability for a long-range trip without the requirement of stop-and-charge. This capability is provided by the on-board auxiliary power unit (APU) which is used to maintain the battery state of charge at a minimum limit. Due to the limited APU package size, a small capacity engine with low-cylindercount is normally used which inherently exposes more severe torque pulsation, that arises from a low firing frequency. By using vector control, it is feasible to vary the generator in-cycle torque to counteract the engine torque oscillation dynamically. This allows for a smoother operation of the APU with the possibility of reducing the size of the engine flywheel. In this paper, a series of motor/generator control torque patterns were applied with the aim of cancelling the engine in-cycle torque pulses.