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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 paper discusses the concept, design and final results from the ‘Ultra Boost for Economy’ collaborative project, which was part-funded by the Technology Strategy Board, the UK's innovation agency. The project comprised industry- and academia-wide expertise to demonstrate that it is possible to reduce engine capacity by 60% and still achieve the torque curve of a modern, large-capacity naturally-aspirated engine, while encompassing the attributes necessary to employ such a concept in premium vehicles. In addition to achieving the torque curve of the Jaguar Land Rover naturally-aspirated 5.0 litre V8 engine (which included generating 25 bar BMEP at 1000 rpm), the main project target was to show that such a downsized engine could, in itself, provide a major proportion of a route towards a 35% reduction in vehicle tailpipe CO2 on the New European Drive Cycle, together with some vehicle-based modifications and the assumption of stop-start technology being used instead of hybridization.

The paper discusses investigations into improving the full-load and transient performance of the Ultraboost extreme downsizing engine by the application of the SuperGen variable-speed centrifugal supercharger. Since its output stage speed is decoupled from that of the crankshaft, SuperGen is potentially especially attractive in a compound pressure-charging system. Such systems typically comprise a turbocharger, which is used as the main charging device, compounded at lower charge mass flow rates by a supercharger used as a second boosting stage. Because of its variable drive ratio, SuperGen can be blended in and out continuously to provide seamless driveability, as opposed to the alternative of a clutched, single-drive-ratio positive-displacement device. In this respect its operation is very similar to that of an electrically-driven compressor, although it is voltage agnostic and can supply other hybrid functionality, too.

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.

The use of Wankel rotary engines as a range extender has been recognised as an appealing method to enhance the performance of Hybrid Electric Vehicles (HEV). They are effective alternatives to conventional reciprocating piston engines due to their considerable merits such as lightness, compactness, and higher power-to-weight ratio. However, further improvements on Wankel engines in terms of fuel economy and emissions are still needed. The objective of this work is to investigate the engine modelling methodology that is particularly suitable for the theoretical studies on Wankel engine dynamics and new control development. In this paper, control-oriented models are developed for a 225CS Wankel rotary engine produced by Advanced Innovative Engineering (AIE) UK Ltd. Through a synthesis approach that involves State Space (SS) principles and the artificial Neural Networks (NN), the Wankel engine models are derived by leveraging both first-principle knowledge and engine test data.

This paper describes the development and automated calibration of a compact analytically based model of the wall-wetting phenomenon of modern port fuel-injected (PFI) spark-ignition (SI) gasoline engines. The wall-wetting model, based on the physics of forced convection with phase change, is to be used in an automated model-based calibration program. The first stage of work was to develop a model of the wall-wetting phenomenon in Matlab. The model was then calibrated using experimental data collected from a 1.8-litre turbocharged I4 engine coupled to a dynamic 200kW AC dynamometer. The calibration was accomplished by adopting a two stage optimization approach. Firstly, a design of experiments (DoE) approach was used to establish the effect of the principal model parameters on a set of metrics that characterized the magnitude and duration of the measured lambda deviation during a transient.

Engine thermal management systems (TMS) are gaining importance in engine development and calibration to achieve low fuel consumption and meet future emissions standards. To benefit from their full potential, a thorough understanding of the effects on engine behavior is necessary. Steady state tests were performed on a 2.0L direct injection diesel engine at different load points. A design of experiments (DoE) approach was used to conduct exhaust gas recirculation (EGR) and injection timing swings at different coolant temperatures. The effect of the standard engine controller and calibration was observed during these tests. The injection timing strategy included a significant dependency on coolant temperature, retarding injection by about 3° crank angle between coolant temperatures of 70°C and 86°C. In contrast, EGR strategy was essentially independent of coolant temperature, though physical interactions were present due in part to the EGR cooler.

Increasing the number of cold-start engine cycles which could be run in any one day would greatly improve the productivity of an engine test facility. However with the introduction of forced cooling procedures there is the inherent risk that test-to-test repeatability will be affected. Therefore an investigation into the effects caused by forced cooling on fuel consumption and the temperature distribution through the engine and fluids is essential. Testing was completed on a 2.4 litre diesel engine running a cold NEDC. The test facility utilises a basic ventilation system, which draws in external ambient air, which is forced past the engine and then drawn out of the cell. This can be supplemented with the use of a spot cooling fan. The forced cool down resulted in a much quicker cool down which was further reduced with spot cooling, in the region of 25% reduction.

A modern high speed four cylinder Diesel engine equipped with high pressure common rail fuel injection equipment has been fitted with extensive instrumentation to allow the heat flux and coolant convective heat transfer coefficient through the cylinder walls to be estimated. The instrumentation was located around the circumference of the cylinder and longitudinally down the cylinder. The engine has been run through the new European drive cycle using a dynamic test stand. From the experimental results it was found that there was a strong correlation between the one dimensional heat flux through the cylinder wall and the engine speed. The changes in heat flux were found to be repeatable over the four repeated ECE sections of the drive cycle. It was also found that the magnitude of heat flux reduced down the length of the cylinder.

This paper investigates the potential for reduced NOx emissions from the integration of thermal factors into the Diesel engine calibration process. NOx emissions from Diesel engines have been shown to be sensitive to engine operating temperature, which is directly related to the level of cooling applied to the engine, in addition to the main engine operating parameters such as injection timing and EGR ratio. Experimental engine characterization of the main engine parameters against coolant temperature set point shows that engine cooling settings can extend the feasible lower limits of fuel consumption and emissions output from Diesel engine. With the adoption of an integrated calibration methodology including engine cooling set point, NOx emissions can be improved by up to 30% at crucial high speed/load operating points seen in the NEDC drive cycle with a minor reduction in fuel economy and small increase in CO output.

A study has been undertaken to demonstrate the use and potential benefits of actively controlled coolant jets in a vehicle. Results have shown that active control of cooling jets has the potential to regulate the temperature of thermally critical areas of the cylinder head, in this case the exhaust valve bridge. In addition the temperature gradient across the head from the exhaust valves to the inlet valves is directly influenced. These capabilities offer improved control of the combustion process and enhanced durability. Furthermore the system allows heat to be rejected at much lower overall coolant flow rates than with a conventional arrangement. The technique relies on an adequate supply of coolant at a lower temperature than that within the engine and on the availability of a suitable measurement technology within the thermally critical region. Unlike passive precision cooling the active jets allow optimization of the cooling at all engine speed / load points.

As emissions regulations become more stringent, an efficient and effective method of rig-based transient engine calibration becomes increasingly desirable. It is known that approximately 80% of total drive-cycle exhaust emissions can be produced in the initial warm-up phase before catalyst ‘light-off’ is achieved and catalyst conversion efficiency increases. During this period, there is a clear trade-off that can be made in the strategy between the amount of thermal energy that is delivered to the catalyst and the amount of exhaust emissions produced during the time before catalyst ‘light-off’ is achieved. This paper examines whether an automated expert-knowledge based decision-making methodology can be used to find a satisfactory trade-off between these two parameters whilst reducing the iteration time and level of input required from a calibration engineer.

The measurement of vehicle modal emissions is technically challenging due to the major issue of determining exhaust gas mass flow rate and ensuring that it is synchronous with the emission measurement of that corresponding ‘slug’ of exhaust gas. This is very evident when attempting to measure small passive NOx catalyst conversion efficiencies. This paper highlights alignment issues with regard to the variation of time delays associated with engine and vehicle events and the CO2 tracer method for determining exhaust gas flows.

The Milner CVT is a patented [1] rolling traction transmission offering advantages of high power density and simplicity of construction and operation. A 90 mm diameter prototype variator is described which was sized for a maximum rated input power of 12 kW. Experimental data are presented demonstrating high efficiency and low shift forces. Resistance to overload torque is shown to be exceptional and preliminary durability trials indicate a highly viable concept for series production. Based upon the measured data, characteristics of larger variators are predicted and prospects for automotive applications discussed.

Electric coolant pumps for IC engines are under development by a number of suppliers. They offer packaging and flexibility benefits to vehicle manufacturers. Their full potential will not be realised, however, unless an integrated approach is taken to the entire cooling system. The paper describes such a system comprising an advanced electric pump with the necessary flow controls and a supervisory strategy running on an automotive microprocessor. The hardware and control strategy are described together with the simulation developed to allow its calibration and validation before fitting in a B/C class European passenger car. Simulation results are presented which show the system to be controllable and responsive to deliver optimum fuel consumption, emissions and driver comfort.

More stringent legislative guidelines on emissions and fuel economy have led to an increased number of engine parameters to be optimised. Steady state engine mapping to produce an empirical engine model remains a fundamental step in this optimisation process. Recently statistical techniques such as design of experiments have been introduced to improve the efficiency of this modeling phase. Before undertaking an experimental design it is first necessary to determine the permissible envelope of the various design parameters. The importance of this limit space is two fold, firstly to ensure that the engine is not operated in regions, which may cause damage to it, and secondly so that subsequent experimentation yields test data wholly valid for the subsequent engine model. Currently this limit space is defined in a largely manual process, requiring expert input many times in the test and characterization process.

Steady state mapping is fundamental to optimizing IC engine operation. Engine variables are set, a predefined settling time elapses, and then engine data are logged. This is an accurate but time consuming approach to engine testing. In contrast the sweep method seeks to speed up data capture by continuously moving the engine through its operating envelope without dwelling. This is facilitated by the enhanced capability of modern test rig control systems. The purpose of this work is to compare the accuracy and repeatability of the sweep approach under experimental conditions, with that of steady state testing. Limiting factors for the accuracy of the sweep approach fall into two categories. Firstly on the instrumentation side - transducers have a characteristic settling time. Secondly on the engine side - thermal and mechanical inertias will mean that instantaneous measurements of engine parameters differ from the steady state values.

A proof-of-concept study has been undertaken to demonstrate the use and potential benefits of actively controlled coolant jets in an IC engine cooling gallery simulator. Results have shown that substantial reductions in coolant volumes are possible and that the control of the liquid/metal surface temperature can be achieved within +/- 0.2°C in response to transient heat flux conditions.

Time-alignment sensitivity studies have been carried out to assess the accuracy of instantaneous mass NOx emissions on a chassis rolls dynamometer. The work is part of a larger project aimed at measuring passive NOx catalyst conversion efficiencies. Instantaneous NOx emissions are examined in relation to the NEDC vehicle speed trace at multi sampling points, and phase and time alignment issues are highlighted and discussed. It has been found that a small mismatch of the vehicle speed trace to the instantaneous mass of emissions of ± 2 seconds can lead to results indicating that the conversion efficiency is anywhere between 0-20%. Finally, examples are presented showing the difficulties of attempting to adjust the time alignment of raw emissions data.

The major contribution of this paper is the general description of a complete integrating procedure of autonomous vehicle system. Using Robot Operating System (ROS) as the framework, process from senor integration to path planning and path tracking were performed. Based on an off-road All-Terrain Vehicle, an Extended Kalman filter based autonomous control strategy was developed on the ROS. Both the position estimation and autonomous control were performed on the ROS platform. For the position estimation phase, sensory measurements from GPS, IMU and wheel odometry were acquired and processed on ROS. In accordance with the ROS architecture, separate packages were developed for each sensor to gather and publish corresponding measurements. Furthermore, Extended Kalman filtering was performed to fuse all sensory measurements to achieve an optimizing accuracy.