Search Results

The efforts of the ISO “Test Variability Task Force” have been aimed at improving the understanding and at reducing brake dynamometer test variability during performance testing. In addition, dynamometer test results have been compared and correlated to vehicle testing. Even though there is already a vast amount of anecdotal evidence confirming the fact that different procedures generate different friction coefficients on the same brake corner, the availability of supporting data to the industry has been elusive up to this point. To overcome this issue, this paper focuses on assessing friction levels, friction coefficient sensitivity, and repeatability under ECE, GB, ISO, JASO, and SAE laboratory friction evaluation tests.

The paper describes a completely new approach to fully variable valve actuation (FVVA), which allows almost unlimited continuously variable control of intake and exhaust valve opening and closing events, and duration without the use of a camshaft. DigitalAir replaces conventional poppet valves with horizontally actuated valves located directly above the combustion deck of the cylinder head, which open and close a number of slots connecting the cylinder with the intake and exhaust ports, Figure 1. The stroke of the valves to provide the full flow area is approximately 25% of the stroke of the equivalent poppet valve, thus allowing direct electrical actuation with very low power consumption. This design arrangement also avoids the risk of poppet valve to piston collision, or the need for cut-outs in the piston crown, since the valves do not open into the cylinder.

This paper proposes and evaluates improvements to a crash simulation of a fuel delivery module in a fuel tank. The simulations were performed in ANSYS/LS-DYNA. Deviations between the original simulation and test data were studied and reasons for the deviations hypothesized. These reasons stemmed from some of the simplifying assumptions of the model. Improvements consisted of incorporating plasticity and strain rate effects into the material models. Performance criteria were also directly incorporated into the material models such that non-performing portions of the model could be deactivated during the simulation. Finally, solid-fluid interactions were added into the simulation to include the momentum transfer from fuel to the fuel delivery module. It was previously thought that effects of a crash would be most severe on the module when the fuel tank was empty and the module was full with fuel.

Networking of active and passive safety is the fundamental basis for comprehensive vehicle safety. Situation-relevant information relating to driver reactions, vehicle behavior and traffic environment are fed into a crash probability calculator, which continually assesses the current crash risk and intervenes when necessary with appropriate measures to avoid a crash and reduce potential injuries. This provides effective protection not only for vehicle occupants but also for other, vulnerable road users. As this functionality up till now only relates to the vehicle itself, the next logical step is enhancement leading to the ultimate goal in safety performance, telematics. The integration of this embedded, in-vehicle wireless communication system allows Car-to-Car (C2C) and Car-to-Infrastructure (C2I) functionality for, e.g. hazard warning. This is an integral element of the cascaded ContiGuard® protection measures.

The AUTomotive Open System ARchitecture (AUTOSAR) Development Partnership has published early 2008 the specifications Release 3.0 [1], with a prime focus on the overall architecture, basic software, run time environment, communication stacks and methodology. Heavy developments have taken place in the OEM and supplier community to deliver AUTOSAR loaded cars on the streets starting 2008 [2]. The 2008 achievements have been: Improving the specifications in order to secure the exploitation for body, chassis and powertrain applications Adding major features: safety related functionalities, OBD II and Telematics application interfaces.

The causes of engine knock are well understood but it is important to be able to relate these causes to the effects of controllable engine parameters. This study attempts to quantify the effects of a portion of the available engine parameters on the knock behavior of a 60% downsized, DISI engine running at approximately 23 bar BMEP. The engines response to three levels of coolant flow rate, coolant temperature and exhaust back pressure were investigated independently. Within the tested ranges, very little change in the knock limited spark advance (KLSA) was observed. The effects of valve timing on scavenge flow and blow through (the flow of fresh air straight into the exhaust system during the valve overlap period) were investigated at two conditions; at fixed inlet/exhaust manifold pressures, and at fixed engine torque. For both conditions, a matrix of 8 intake/exhaust cam combinations was tested, resulting in a wide range of valve overlap conditions (from 37 to -53°CA).

The major contribution of this paper is to propose a low-cost accurate distance estimation approach. It can potentially be used in driver modelling, accident avoidance and autonomous driving. Based on MATLAB and Python, sensory data from a Continental radar and a monocular dashcam were fused using a Kalman filter. Both sensors were mounted on a Volkswagen Sharan, performing repeated driving on a same route. The established system consists of three components, radar data processing, camera data processing and data fusion using Kalman filter. For radar data processing, raw radar measurements were directly collected from a data logger and analyzed using a Python program. Valid data were extracted and time stamped for further use. Meanwhile, a Nextbase monocular dashcam was used to record corresponding traffic scenarios. In order to measure headway distance from these videos, object depicting the leading vehicle was first located in each frame.

Modern automotive engines almost exclusively operate on the 4-stroke Otto cycle and utilize poppet valves for gas exchange. This state of affairs has not always been the case, however, and one unusual and relatively successful technology that was once in mass production (albeit in piston aero engines) was the Burt-McCollum single sleeve valve. This paper investigates the timing and angle-area of a Bristol Centaurus engine cylinder, which utilized such a single sleeve valve for gas exchange, using some modern tools. A comparison with poppet valve angle-areas is made. Finally, the results are also used to study the potential of variable valve timing and the interaction with variable compression ratio of a single sleeve mechanism.

The turbo-compounding has been extensively researched as a mean of improving the overall thermal efficiency of the internal combustion engine. Many of the studies aiming to optimize the turbo-compounding system lead to the unified conclusion that this approach is more suitable for the operation under constant high load condition, while it has little effect on improving the fuel economy under low load conditions. Besides, in a traditional series turbo-compounding engine, the increased back pressure unavoidably results in a serious parasitic load to the system by increasing the resistance to the scavenging process. In order to improve this situation, a novel turbo-compounding arrangement has been proposed, in which the turbocharger was replaced by a continuously variable transmission (CVT) coupled supercharger (CVT superchargedr) to supply sufficient air mass flow rate to the engine at lower engine speeds.

SuperGen is a Belt Integrated Starter Generator (B-ISG) combined with a novel electro-mechanical power split transmission system providing variable speed centrifugal supercharger capability, all in one compact package. This paper initially discusses the analysis of SuperGen application to a gasoline SUV in order to examine the BISG power and voltage mild hybrid functionality trade-off versus fuel consumption reduction on drive cycle. A significant engine down speeding was also applied based on the low speed torque enhancement afforded by SuperGen boosting capability, both transiently, and sustainably at steady state engine operation. This has been demonstrated and reported on the well-published Jaguar Land Rover (JLR) Ultraboost project.

In the research project between the Institute of Automotive Engineering (FZD) of the Technische Universität Darmstadt (TUD) and Continental Teves AG & Co. oHG a new modeling concept has been developed. With the aim to enhance the current development process, the brake caliper is modeled based on coupled rigid bodies integrated into a nonlinear system model. Using an explicit interface definition, the number of degrees of freedom is minimized and the calculation of caliper performance is possible over a wide range of parameters. Compared to models based on the Finite Element Method (FEM), fully parameterized geometry from CAD is not necessary, thus the caliper can be optimized for a variation of its geometrical and physical parameters. With this modeling approach, typical performance criteria such as caliper fluid displacement, hysteresis, uneven pad wear and residual torque can be calculated in a virtual bench test.

With ever stricter legislative requirements for CO2 and other exhaust emissions, significant efforts by OEMs have launched a number of different technological strategies to meet these challenges such as Battery Electric Vehicles (BEVs). However, a multiple technology approach is needed to deliver a broad portfolio of products as battery costs and supply constraints are considerable concerns hindering mass uptake of BEVs. Therefore, further investment in Internal Combustion (IC) engine technologies to meet these targets are being considered, such as lean burn gasoline technologies alongside other high efficiency concepts such as dedicated hybrid engines. Hence, it becomes of sound reason to further embrace diversity and develop complementary technologies to assist in the transition to the next generation hybrid powertrain. One such approach is to provide increased valvetrain flexibility to afford new degrees of freedom in engine operating strategies.

The US American government introduced a law to mandatorily equip passenger vehicles with rear view cameras. Furthermore, US NCAP presented a test for passenger vehicles to brake on pedestrians while back up. These two circumstances lead to main motivation of the development of the Comfort Backup Assist (CBUA). Nevertheless, more and more passenger cars in general are being equipped with rear view cameras. Rear view system (RVS) allows to deliver a rear-view camera system including a braking functionality which is intended to make the driving mission safer and reduce the number of accidents in parking driving situations. RVS also focus on vehicle safety by reducing accidents while taking reversing/parking scenarios and to provides slow de-acceleration of the vehicle gradually to avoid jerk and increase the ride comfort.

Driver assistance features have been introduced to the market focusing on basic, independent functional scenarios. The trend is showing that these kinds of products are facing more and more complex scenarios and we are transitioning from single independent functions to a strongly networked system. Some of the drivers for future autonomous vehicles are 360° monitoring by active safety technology and V2X (vehicle to vehicle or vehicle to infrastructure) communication. In the past vehicles were strictly operated by the driver. Advanced driver assistance products added so called feedback features like lane departure warning, forward collision warning, and blind spot monitoring. First steps towards semi-autonomous driving started with the development of active support functions like adaptive cruise control or lane keeping support. Collision mitigation with various authority levels is the next milestone towards automation followed by other, even more advanced, features.

This work represents a further contribution to reporting experimental activities carried out on a modern Wankel rotary engine. Specifically, in this study, the firing performance of the Advanced Innovative Engineering 225CS engine is analysed. Preliminary presentations of the experimental and measurement setup and a motoring analysis were extensively covered in Part I and II of this suite of papers while the current work presents the combustion analysis of the firing indicated pressure cycles collected through the bespoke combustion analyser software developed within the project. With the Wankel rotary engine gaining popularity again due to its potential as a range extender for battery electric vehicles, the aim of this work was mainly to analyse the fuel consumption together with the overall efficiency and the emissions at different engine speeds and loads as per classic steady-state engine testing.

Recent interest in the possible use of Wankel engines as range extenders for electric vehicles has prompted renewed investigations into the concept. While not presently used in the automotive industry, the type is well established in the unmanned aerial vehicles industry, and several innovative approaches to sealing and cooling have recently been developed which may result in improved performance for ground vehicle applications. One such UAV engine is the 225CS, a 225 cc/chamber single-rotor engine manufactured by Advanced Innovative Engineering (UK) Ltd. To be able to analyse the parameters, opportunities and limitations of this type of engine a model was created in the new dedicated Wankel modelling environment of AVL BOOST. For comparison a second model was created using the established method of modelling Wankel engines by specifying an ‘equivalent’ 3-cylinder 4-stroke reciprocating engine.

Compressed natural gas (CNG) is an attractive, alternative fuel for spark-ignited (SI), internal combustion (IC) engines due to its high octane rating, and low energy-specific CO2 emissions compared with gasoline. Directly-injected (DI) CNG in SI engines has the potential to dramatically decrease vehicles’ carbon emissions; however, optimization of DI CNG fueling systems requires a thorough understanding of the behavior of CNG jets in an engine environment. This paper therefore presents an experimental and modeling study of DI gaseous jets, using methane as a surrogate for CNG. Experiments are conducted in a non-reacting, constant volume chamber (CVC) using prototype injector hardware at conditions relevant to modern DI engines. The schlieren imaging technique is employed to investigate how the extent of methane jets is impacted by changing thermodynamic conditions in the fuel rail and chamber.

Accuracy of clutch torque model which converts target torque to target stroke is essential to control the dry clutch system. Continuous Adaptation algorithm requires micro slip control during in-gear driving. Clutch judder during micro slip control can cause detrimental effect on the output of controller as slip speed is calculated by deviation of engine speed and clutch speed. Conventional approach to avoid clutch judder is using low pass filter to the input of controller which is slip speed. But this affect to the overall response time of slip controller. In this paper, signal processing algorithm is design and tested for the clutch speed(Input shaft speed). With low pass filter in clutch speed, clutch judder signal is decreased but overall time delay creates static error during acceleration. Several phase advance algorithm is designed to overcome the static error during acceleration without disadvantage of decreasing clutch judder signal.

Global automotive fuel economy and emissions pressures mean that 48 V hybridisation will become a significant presence in the passenger car market. The complexity of powertrain solutions is increasing in order to further improve fuel economy for hybrid vehicles and maintain robust emissions performance. However, this results in complex interactions between technologies which are difficult to identify through traditional development approaches, resulting in sub-optimal solutions for either vehicle attributes or cost. The results presented in this paper are from a simulation programme focussed on the optimisation of various advanced powertrain technologies on 48 V hybrid vehicle platforms. The technologies assessed include an electrically heated catalyst, an insulated turbocharger, an electric water pump and a thermal management module.

Reductions of hardware costs as well as implementations of new innovative functions are the main drivers of today's automotive electronics. Indeed more and more resources are spent on adapting existing solutions to different environments. At the same time, due to the increasing number of networked components, a level of complexity has been reached which is difficult to handle using traditional development processes. The automotive industry addresses this problem through a paradigm shift from a hardware-, component-driven to a requirement- and function-driven development process, and a stringent standardization of infrastructure elements. One central standardization initiative is the AUTomotive Open System ARchitecture (AUTOSAR). AUTOSAR was founded in 2003 by major OEMs and Tier1 suppliers and now includes a large number of automotive, electronics, semiconductor, hard- and software companies.