Refine Your Search

Search Results

Technical Paper

Development of a Standardized Test to Evaluate the Effect of Gasoline Engine Oil on the Occurrence of Low Speed Pre-Ignition - The Sequence IX Test

2018-09-10
2018-01-1808
The study described in this paper covers the development of the Sequence IX Low Speed Pre-Ignition (LSPI) test for the new engine oil category, ILSAC GF-6. The purpose of the Sequence IX test is to evaluate a lubricant’s ability to protect against LSPI events which are prevalent when operating a highly boosted/downsized gasoline direct-injected engine. LSPI is characterized as a combustion event that starts before ignition spark, typically followed by excessive in-cylinder pressures and heavy knock, which can cause severe engine damage and failure. Industry research has shown that oil formulation can contribute to the frequency of LSPI activity. The Sequence IX test was developed using a turbocharged gasoline direct-injected 2.0 liter Ford Ecoboost engine with dual independent variable cam timing. The engine was modified with in-cylinder pressure sensors and a high-resolution crank angle encoder to characterize individual engine combustion cycles and identify potential LSPI events.
Technical Paper

Combustion Characteristics of PRF and TSF Ethanol Blends with RON 98 in an Instrumented CFR Engine

2018-09-10
2018-01-1672
The CFR F1 engine is the standard testing apparatus used for rating the research octane number (RON) of gasoline fuels. Unlike the motor octane number (MON) method, where the intake port temperature after the carburetor is controlled by an electric heater, the mixture temperature can vary during the RON test due to the heat of vaporization (HoV) of the fuel. Ethanol is receiving increasing attention as a high octane and high HoV fuel component. This work presents an analysis of the combustion characteristics during the RON rating of ethanol fuel blends according to the standard ASTM D2699 method, highlighting the effects of ethanol concentration and base fuel composition. All fuels were blended to a constant RON of 98. Ethanol levels varied from 0 to 50 vol% and the base fuels were surrogate blends composed of primary reference fuels (PRF), toluene standardization fuels (TSF), and a four component gasoline surrogate.
Technical Paper

Effect of Thermocouple Size on the Measurement of Exhaust Gas Temperature in Internal Combustion Engines

2018-09-10
2018-01-1765
Accurate measurement of exhaust gas temperature in internal combustion engines is essential for a wide variety of monitoring and design purposes. Typically these measurements are made with thermocouples, which may vary in size from 0.05 mm (for fast response applications) to a few millimetres. In this work, the exhaust of a single cylinder diesel engine has been instrumented both with a fast-response probe (comprising of a 50.8 μm, 127 μm and a 254 μm thermocouple) and a standard 3 mm sheathed thermocouple in order to assess the performance of these sensors at two speed/load conditions. The experimental results show that the measured time-average exhaust temperature is dependent on the sensor size, with the smaller thermocouples indicating a lower average temperature for both speed/load conditions. Subject to operating conditions, measurement discrepancies of up to ~80 K have been observed between the different thermocouples used.
Technical Paper

Simulated Bearing Durability and Friction Reduction with Ultra-Low Viscosity Oils

2018-09-10
2018-01-1802
Legislation aimed at reducing carbon dioxide emissions is forcing significant changes in passenger car engine hardware and lubricants. Reduced viscosity lubricants can reduce friction levels and are therefore helpful to manufacturers seeking legislative compliance. MAHLE and Shell have worked together to determine the crankshaft, bearing and lubricant combination which minimizes friction with an acceptable level of durability. This paper describes the results of our joint simulation studies. MAHLE Engine Systems have developed in-house simulation packages to predict bearing lubrication performance. SABRE-M is a “routine” simulation tool based on the mobility method [1] curve fitting from the finite bearing theory to simulate the hydrodynamic lubrication in steady-state conditions. Whereas, SABRE-TEHL is a specialized simulation package used for performing Thermo-Elasto-Hydrodynamic Lubrication (TEHL) analysis of bearing systems.
Technical Paper

High-Accuracy Viscosity-Temperature Model for Engine Simulation

2018-09-10
2018-01-1805
In an era of accelerated engine efficiency development, the ability to accurately model lubricant performance is becoming increasingly important. The general behaviour of engine lubricant viscosity with temperature is well understood and for most applications the widely accepted models of Walther and Vogel are deemed accurate enough in their prediction of decreasing viscosity with increasing temperature. However, as we move further into a digitized age it becomes apparent there is a need for a single expression higher accuracy equation which captures this behaviour to better facilitate its use in automotive engineering simulation software (Computer Aided Engineering -CAE). Ideally it would be beneficial for a viscosity model to include standard viscosity parameters in a single expression that could be calibrated directly using standard viscosity measurements that are already in common use.
Technical Paper

Prediction of Lubricant Performance in an EHL Valvetrain Simulation Using an Equation of State and Detailed Rheology Characterization Approach

2018-09-10
2018-01-1806
With the continued CO2 reduction challenges for automotive engines, it becomes necessary to minimize friction losses. Many studies in the past have used generic equations of state to account for changes in density, neglecting the compressibility difference between fluids, whereas this study used accurately measured equations of state, for each of the oils. Density change is generally only accounted for in terms of mass conservation, an effort has been made here to develop a link between viscosity characteristics and density, by separating molecular density and molecular interaction contributions rather than using an all-encompassing pressure-viscosity coefficient. Several studies have not accounted for all physical aspects acting within an elasto-hydrodynamic contact, because of the difficulties associated with model convergence.
Technical Paper

Effect of Mesh Size in Numerical Simulation of Turbine Housing in Turbocharger

2018-09-10
2018-01-1715
Numerical method is popular in analyzing turbine housing in turbocharger with an early and rapid risk assessment. However, complex casting and extreme thermal loading from exhaust gas temperature and flow variation under engine duty cycle lead to big thermal stress and this makes material serviced in the plastic zone. Previous numerical simulations show that a mesh size is insensitive to the elastic finite element analysis (FEA), but might not be proper for elastic-plastic FEA, even that other boundary conditions keep same, which indicating simulation results are changeable with mesh size and a simple numerical mesh size convergence might not be enough to guarantee accurate numerical results as well. Therefore, several different mesh sizes are used in elastic-plastic analysis of turbine housing to investigate the influence on numerical results.
Technical Paper

Critical Analysis of PM Index and Other Fuel Indices: Impact of Gasoline Fuel Volatility and Chemical Composition

2018-09-10
2018-01-1741
Among the challenges for the future facing the development of gasoline engines, one of the most important is the reduction of particles emissions. This study proposes a critical and objective evaluation of the influence of fuel characteristics on gasoline particles emission through the use of Fuel Particle Indices. For this, a selected fuel matrix composed of 22 fuels was built presenting different volatility and chemical composition (content in total aromatics, heavy cuts and ethanol). To represent the fuel sooting tendency, seven Fuel Particle Indices were selected based on a literature review, namely, Particulate Matter Index (PMI), Particulate Number index (PNI), Threshold Sooting index (TSI), Smoke point (SP), Oxygen Extended Sooting Index (OESI), Simplified index 1 and 2 (sPMI 1, sPMI 2). These indices were computed on the fuel matrix and compared on the basis of three main axes. First, the sensitivity to fuel variation.
Technical Paper

POMDME as an Alternative Pilot Fuel for Dual-Fuel Engines: Optical Study in a RCEM and Application in an Automotive Size Dual-Fuel Diesel Engine

2018-09-10
2018-01-1734
Dual-fuel natural gas engines are seen as an attractive solution for simultaneous reduction of pollutant and CO2 emissions while maintaining high engine thermal efficiency. However, engines of this type exhibit a tradeoff between misfire as well as high UHC emissions for small pilot injection amounts and higher emissions of soot and NOX for operation strategies with higher pilot fuel proportion. The aim of this study was to investigate POMDME as an alternative pilot fuel having the potential to mitigate the emissions tradeoff, enabling smokeless combustion due to high degree of oxygenation, and being less prone to misfire due to its higher cetane number. Furthermore, POMDME can be synthetized carbon neutrally. First, characteristics of POMDME ignition in methane/air mixture and the transition into premixed flame propagation were investigated optically in a rapid compression-expansion machine (RCEM) by employing Schlieren and OH* chemiluminescence imaging.
Technical Paper

Effect of Fuel Injection Strategy on Nano-Particle Emissions from RCCI Engine

2018-09-10
2018-01-1709
Increase in the air pollution has driven the research towards the cleaner combustion technology for reciprocating engines. To tackle the challenge of the trade-off between the NOx and soot emissions from a conventional diesel engine, premixed low-temperature combustion (LTC) strategies are potential technologies. Among the LTC strategies, reactivity controlled compression ignition (RCCI) strategy has a better combustion phasing control along with higher fuel conversion efficiency and lower NOx and soot emissions. The present study investigated the nano-particle emissions from RCCI engine fueled with a port injection of gasoline/methanol (low reactivity fuel) and direct injection of diesel (high reactivity fuel). The RCCI combustion experiments were performed on a modified single cylinder compression ignition engine with development ECU. The mass of injected fuel per stroke for the port as well as the direct injection is controlled through ECU.
Technical Paper

Effect of Diesel Injection Timing on Peak Pressure Rise Rate and Combustion Stability in RCCI Engine

2018-09-10
2018-01-1731
In the present study, experiments of reactivity control compression ignition (RCCI) combustion mode is performed on a single cylinder automotive diesel engine with development ECU (electronic control unit). For achieving RCCI combustion mode, low reactivity fuel (i.e., gasoline/methanol) is injected into the intake manifold, and high reactivity fuel (i.e., diesel) is directly injected into the engine cylinder. Mass of fuel injection per cycle and their injection events are controlled using ECU. This study presents the experimental investigation on the effect of high reactivity fuel injection timings on peak pressure rise rate (PPRR) and combustion stability in RCCI engine. The combustion parameters, i.e., PPRR, indicated mean effective pressure (IMEP) and total heat release (THR) are calculated from the in-cylinder pressure measurement data. In-cylinder pressure is measured using a piezoelectric pressure transducer installed on the engine cylinder head.
Technical Paper

An Optical Study on the Combustion of Gasoline/PODEn Blends in a Constant Volume Vessel

2018-09-10
2018-01-1748
Polyoxymethylene dimethyl ethers (PODEn) have high cetane number, high oxygen content and high volatility, therefore can be added to gasoline to optimize the performance and soot emission of Gasoline Compression Ignition (GCI) combustion. High speed imaging was used to investigate the spray and combustion process of gasoline/PODEn blends (PODEn volume fraction 0%-30%) under various ambient conditions and injection strategies in a constant volume vessel. Results showed that with an increase of PODEn proportion from 10% to 30%, liquid-phase penetration of the spray increased slightly, ignition delay decreased from 3.8 ms to 2.0 ms and flame lift off length decreased 29.4%, causing a significant increase of the flame luminance. For blends with 20% PODEn, when ambient temperature decreased from 893 K to 823 K, the ignition delay increased 1.3 ms and the flame luminance got lower.
Technical Paper

Super Low Viscosity ATF; AW-2

2018-09-10
2018-01-1756
Reducing loss torque in automatic transmissions (ATs) is a key factor in improving fuel economy. A promising approach is to reduce the viscosity of the Automatic Transmission Fluid (ATF) so as to minimize churning loss. Aisin AW and JXTG Nippon Oil & Energy Corporation have developed a super low viscosity ATF, called “AW-2”, which has approximately 50% lower kinematic viscosity at 40 °C compared to the conventional ATF “AW-1”. It is generally understood that if the viscosity of an ATF is too low, it can have a negative impact on the fatigue life of components such as gears and bearings, and possibly lead to increased wear or seizure. AW-2 was designed to solve these problems via the application of two key technologies. The first is a high performance base oil with a low traction coefficient, which translates to low viscosity under high pressure conditions.
Technical Paper

A Robust Path Tracking Control Method for Intelligent Vehicle

2018-08-07
2018-01-1582
This paper presents a strong robust path tracking control method which is based on sliding mode control and active disturbance rejection control. Firstly, by constructing a desired yaw angle function, which can guarantee that the deviations of the vehicle actual lateral displacement from the desired path converges to zero when the yaw angle of the vehicle approaches the desired yaw angle, so that the complex path tracking control problem can be transformed into easy to implement yaw angle tracking control problem. Then, a robust vehicle yaw angle tracking controller is constructed. The controller consists of two parts: the extended state observer and the nonlinear error feedback control law. The extended state observer is used to estimate the unmodeled dynamics and unknown external perturbations of the system in real time.
Technical Paper

UWB Location Algorithm Based on BP Neural Network

2018-08-07
2018-01-1605
In order to solve the problem that in the traditional trilateral positioning algorithm, the final positioning error is large when there is a certain error in the measured three-sided distance, a UWB positioning algorithm based on Back Propagation (BP) neural network is proposed. The algorithm utilizes the fast learning characteristic and the ability of approximating any non-linear mapping of neural network, and realizes the location of the mobile label through the TOA measurement value provided by the base station and the BP neural network. By comparing the traditional trilateral positioning algorithm, the BP neural network algorithm based on four distance inputs and the BP neural network algorithm based on four distance inputs with trilateral positioning coordinates, it can be seen that the positioning error of traditional trilateral positioning algorithm is 30 cm, and the positioning error of the positioning algorithm based on the BP neural network proposed in this paper is 10 cm.
Technical Paper

Automatic Azimuth Alignment for Automotive Radar

2018-08-07
2018-01-1606
The world has witnessed the rapid development of the Advanced Driver Assist System (ADAS) industry over the past few years. Radar, as one of the most important sensors in ADAS due to its high penetration, all-weather characteristic and low cost, is studied intensively. Automobile radar has many applications like ACC (Advanced Cruise Control), BSD (Blind Spot Detection), LCA (Lane Change Assistant), etc., and the accuracy of the radar target detection influences the performance of ADAS. In general, range, velocity, azimuth angle and other target attributions are measured by the automotive radar, and the accuracy of the azimuth angle is more easily affected by the environment than other attributions. For the automotive radar, it is usually equipped either near a front bumper, or near a left rear and right rear bumper.
Technical Paper

Camera-Radar Data Fusion for Target Detection via Kalman Filter and Bayesian Estimation

2018-08-07
2018-01-1608
Target detection is essential to the advanced driving assistance system (ADAS) and automatic driving. And the data fusion of millimeter wave radar and camera could provide more accurate and complete information of targets and enhance the environmental perception performance. In this paper, a method of vehicle and pedestrian detection based on the data fusion of millimeter wave radar and camera is proposed to improve the target distance estimation accuracy. The first step is the targets data acquisition. A deep learning model called Single Shot MultiBox Detector (SSD) is utilized for targets detection in consecutive video frames captured by camera and further optimized for high real-time performance and accuracy. Secondly, the coordinate system of camera and radar are unified by coordinate transformation matrix. Then, the parallel Kalman filter is used to track the targets detected by radar and camera respectively.
Technical Paper

Semantic Segmentation for Traffic Scene Understanding Based on Mobile Networks

2018-08-07
2018-01-1600
Real-time and reliable perception of the surrounding environment is an important prerequisite for advanced driving assistance system (ADAS) and automatic driving. And vision-based detection plays a significant role in environment perception for automatic vehicles. Although deep convolutional neural networks enable efficient recognition of various objects, it has difficulty in accurately detecting special vehicles, rocks, road pile, construction site, fence and so on. In this work, we address the task of traffic scene understanding with semantic image segmentation. Both driveable area and the classification of object can be attained from the segmentation result. First, we define 29 classes of objects in traffic scenarios with different labels and modify the Deeplab V2 network. Then in order to reduce the running time, MobileNet architecture is applied to generate the feature map instead of the original models.
Technical Paper

Decade of Vision-Based Pedestrian Detection for Self-Driving: An Experimental Survey and Evaluation

2018-08-07
2018-01-1603
With the steady progress in autonomous driving technology and the tremendous potential prospects for development, the topics about self-driving car have begun to return to the center stage of AI applications. Hence, lots of efforts are made on algorithms relevant to self-driving car itself. However, few shed the light on the problem of how to testify them thoroughly, therefore unified standards for autonomous driving and testing are urgently needed. To study this problem, we begin by pedestrian detection, for that the ability of locating humans is one of the most critical problems that should be concerned about for self-driving cars. In this paper, we investigate to perform a standard evaluation to qualify different methods and detectors under a more practical manner. Specifically, we investigate several commonly used evaluation methodologies for pedestrian detection, and find out that the Caltech pedestrian detection benchmark is the most popular.
Technical Paper

The Effect of Mounting Orientation of Resistive Particulate Matter Sensor on Signal Behavior

2018-08-07
2018-01-1598
Particulate Matter (PM) sensors are required to monitor the diesel particulate filters (DPF) malfunction. The resistive PM sensor concept is widely chosen for this purpose due to its functionality, costs and durability. The output signal of resistive PM sensor for interpreting and processing for diagnosing DPF status is significantly affected by the exhaust velocity and soot concentration in the vicinity of sensor sensing element. Theoretically, during the regeneration of PM sensor, no new accumulation of particles is possible. Even after the regeneration, PM cannot immediately be accumulated again, because of thermal inertia, the PM sensor requires a certain time for the thermalization of the sensor element by the exhaust gas. During the regeneration phase and the subsequent cooling phase, PM sensor is insensitive with respect to a possibly present soot concentration, but the choking phenomena of PM sensor can be observed, when soot depositing rate reaches a threshold value.
X