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Technical Paper

Characteristics of Transient NO Emissions Based on the First Firing Cycle Analysis of Cold-Start

2006-04-03
2006-01-1050
The First Firing Cycle (FFC) is very important at cold-start. Misfiring of the first firing cycle can lead to significant HC emissions and affect the subsequent cycles. This paper presents an investigation of characteristics of transient NO emissions in a small LPG SI engine with electronic gaseous injection system. To determine the optimal excess air coefficient ( λ=[A/F]/[A/F]stoic) of the first firing cycle, the emission of instantaneous NO was proposed as a useful criterion to judge if the combustion is occurred or not. A fast response NO detector- Cambustion fNOx400, based on the chemiluminescence's (CLD) method, has been employed to measure continuous, transient emissions of NO during the first firing cycle in the exhaust port of the engine. At the same time, the transient cylinder pressure, instantaneous crankshaft speed of the engine and engine-out HC emissions were measured and recorded.
Technical Paper

A Study of Crevice HC Mechanism Based on the Transient HC Test Data and the Double Zone Combustion Model

2008-06-23
2008-01-1652
The effectiveness of after-treatment systems depends on the exhaust gas temperature, which is low during cold-start. As a result, Euro III, Euro IV and FTP75 require that the emissions tests include exhaust from the beginning of cold start. It is proved that 50%∼80% of HC and CO emissions are emitted during the cold start and the amount of unburned fuel from the crevices during starting is much higher than that under warmed engine conditions. The piston crevices is the most part of combustion chamber crevices, and results of mathematical simulations show that the piston crevice contribution to HC emissions is expected to increase during cold engine operation. Based on the transient HC test data and the double zone combustion model, this paper presents the study of the crevice HC Mechanism of the first firing cycle at cold start on an LPG SI Engine. A fast-response flame ionization detector (FFID) was employed to measure transient HC emissions of the first firing cycle.
Technical Paper

Elementary Investigation into Road Simulation Experiment of Powertrain and Components of Fuel Cell Passenger Car

2008-06-23
2008-01-1585
It is very important to investigate how road irregularity excitation will affect the durability, reliability, and performance degradation of fuel cell vehicle powertrain and its key components, including the electric motor, power control unit, power battery package and fuel cell engine system. There are very few published literatures in this research area. In this paper, an elementary but integrated experimental work is described, including the real road load sample on proving ground, road load reproduction on vibration test rig, total vehicle road simulation test and key components vibration tests. Remote parameter control technology is adopted to reproduce the real road load on road simulator and six-degree-of-freedom vibration table, which is used respectively for total vehicle and components vibration tests.
Technical Paper

Design and Simulation of Serial Hybrid Electric Moped Powertrain

2008-06-23
2008-01-1567
According to the requirements of two-wheel vehicle's future market and the characteristic of urban road conditions in China, the advantages and disadvantages of three basic configurations for the Hybrid Electric Vehicle are compared, finally, the serial hybrid configuration is chosen to be applied to hybrid Electric Moped solution. The selection principle of main components of this hybrid powertrain system includes ICE, generator, battery and hub motor, and the optimal match for performance parameters of these components are introduced in this paper. Then, a hybrid system model is established based on AVL-CRUISE. The simulations of fuel efficiency and exhaust emissions for both serial hybrid moped and conventional motorcycle is offered.
Technical Paper

The Social Economical Benefit Estimation by HEVs Application-Shanghai Case Study

2008-06-23
2008-01-1565
In this paper, a case study of Shanghai HEVs application and its effects on the social and environmental benefits are presented based on the multi views on the different aspects, such as, not only for the fuel consumption saving, but also emissions reduction and health effect, agriculture loss and cleaning cost. The results show that the potential benefits for the society from HEVs application are markedly with the increase of the ratio of HEV in the population of vehicle. Based on this, the policy to promote the HEV purchased by consumers is very important at the beginning of HEV into market.
Technical Paper

Theoretical and Practical Mechanisms on Lowering Exhaust Emission Levels for Diverse Types of Spark Ignition Engines

2008-06-23
2008-01-1545
The exhaust aftertreatment strategy is one of the most fundamental aspects of spark ignition engine technologies. For various types of engines (e.g., carburetor engine, PFI engine and GDI engine), measuring, purifying, modeling, and control strategies regarding the exhaust aftertreatment systems vary significantly. The primary goal of exhaust aftetreatment systems is to reduce the exhaust emission levels of NOx, HC and CO as well as to lower combustion soot. In general, there is a tradeoff among different engine performance aspects. The exhaust catalytic systems, such as the three way catalyst (TWC) and lean NOx trap (LNT) converters, can be applied together with the development of other engine technologies (e.g., variable valve timing, cold start). With respect to engine soot, some advanced diagnosing techniques are essential to obtain thorough investigation of exhaust emission mechanisms.
Technical Paper

Study on EP Energy-Saving Vehicle

2008-06-23
2008-01-1775
The price of fossil fuels and the increasing inexorable energy crisis have become vital issues for everyone. Tongji University EconoPower Racing Team was established to participate in the “Honda EconoPower Cup” annually. Every contestant in the competition must finish a certain distance in the fixed time, with the gasoline supplied by the committee. After that the committee will measure the fuel consumption of every team and calculate the distance per liter fuel (the farther the better) to determine the champion. In order to enhance the EP vehicle's achievement we've made some improvements, such as framework, body, engine's optimization and so on. In this passage we mainly state some details of our research approaches in framework, steering, transmission, shape and driving strategy. The main technologies were: friction reduction, lightweight, enhancement of power train efficiency, tire selection and driving strategy.
Technical Paper

Study on Improving the Fuel Economy of the Engine on EP Energy-Saving Vehicle

2008-06-23
2008-01-1780
“Soichiro Honda Cup, Honda Econo-Power Competition”, is an annual international energy-saving competition which is hosted by Honda Motor Co., Ltd. Till now it has been held 27 sessions. The aims of the EP project are: promoting the development of environmental protection, making full use of limit earth resources, challenging the fuel consumption limitation of vehicle. Tongji University's students' team has participated in the competition for seven consecutive times. In order to minimize the fuel consumption of the EP energy-saving vehicle, this paper focuses on the technical methods of improving the fuel economy of the engine. Firstly, the optimization of the carburetor. Secondly, for the purpose of improving combustion efficiency, researches on dual spark plug and compression ratio are done.
Technical Paper

Characteristics of Combustion and Emissions in a DI Engine Fueled with Biodiesel Blends from Soybean Oil

2008-06-23
2008-01-1832
Combustion and emission characteristics of diesel and biodiesel blends (soybean methyl ester) were studied in a single-cylinder Direct Injection (DI) engine at different loads and a constant speed. The results show that NOx emission and fuel consumption are increased with increasing biodiesel percentage. Reduction of smoke opacity is significant at higher loads with a higher biodiesel ratio. Compared with the baseline diesel fuel, B20 (20% biodiesel) has a slight increase of NOx emission and similar fuel consumption. Smoke emission of B20 is close to that of diesel fuel. Results of combustion analysis indicate that start of combustion (SOC) for biodiesel blends is earlier than that for diesel. Higher biodiesel percentage results in earlier SOC. Earlier SOC for biodiesel blends is due to advanced injection timing from higher density and bulk modulus and lower ignition delay from higher cetane number.
Technical Paper

Characteristics of Output Performances and Emissions of Diesel Engine Employed Common Rail Fueled with Biodiesel Blends from Wasted Cooking Oil

2008-06-23
2008-01-1833
In this paper, the characteristics of performance and emissions of diesel and biodiesel blends are studied in a four-cylinder DI engine employing common rail injection system. The results show that engine output power is further reduced and brake specific fuel consumption (BSFC) increased with the increase of the blend concentration. B100 provides average reduction by 8.6% in power and increase by 11% in BSFC. With respect to the emissions, although NOx emissions were increased with increasing the blend concentration, the increase depends on the load. Filter smoke number is reduced with increasing the blend concentration. At the same time, NO, NO2 and other specific emissions are also investigated. In addition, difference of performance and emission between standard parameters of ECU and modified parameters of ECU is investigated for B10 and B20 based on same output power. The results show that NOx emission and FSN are still lower than baseline diesel.
Technical Paper

Characteristics of Particulates and Exhaust Gases Emissions of DI Diesel Engine Employing Common Rail Fuel System Fueled with Bio-diesel Blends

2008-06-23
2008-01-1834
In this paper, characteristics of gas emission and particle size distribution are investigated in a common rail diesel engine fueled with biodiesel blends. Gas emission and particle size distribution are measured by AVL FTIR - SESAM and SMPS respectively. The results show that although biodiesel blends would result in higher NOx emissions, characteristics of NOx emissions were also dependent on the engine load for waste cooking oil methyl ester. Higher blend concentration results in higher NO2 emission after two diesel oxidation catalyst s (DOC). A higher blend concentration leads to lower CO and SO2 emissions. No significant difference of Alkene emission is found among biodiesel blends. The particle size distributions of diesel exhaust aerosol consist of a nucleation mode (NM) with a peak below 50N• m and an accumulation mode with a peak above 50N • m. B100 will result in lower particulates with the absence of NM.
Technical Paper

Optimal Design of Vehicle Dash and Floor Sound Package Based on Statistical Energy Analysis

2015-04-14
2015-01-0661
An increasing demand for vehicle noise control has been proposed and at the same time, vehicle weight and fuel economy have become critical for the automotive industry. The methodology of statistical energy analysis (SEA) is used to balance both light weight and high noise insulation performance. In this paper, the vehicle dash and floor sound package systems, which are two of the major paths for vehicle interior noise, are studied and optimized by CAE and testing technology. Two types of sound packages which are the conventional insulation system and the lightweight one are chosen for the vehicle dash and floor system. The vehicle dash and floor systems are modeled by SEA and the transmission loss (TL) of the dash and floor system is analyzed, respectively. Several influence factors of the TL are also analyzed, such as sound package coverage, the leaks, etc.
Technical Paper

Fuel Economy and Emissions of a 7L Common Rail Diesel Engine during Torque Rise Transient Process

2015-04-14
2015-01-1068
Previous studies have indicated that longer torque increase time benefits the reduction of emissions during transient process for a diesel engine. However, quantitative conclusions on reduction of emissions and effects on fuel economy have not been made clear so far. The aim of this study was to evaluate the transient process of diesel engine under different torque increase time, and to find the quantitative statement between torque increase time, fuel economy and engine-out emissions. To do this, experiment was carried out on a 7L common rail diesel engine used for commercial vehicles. Three engine speeds (1100r·min−1, 1300r·min−1 and 1500r·min−1) were chosen to represent an engine working range. For each speed, the engine torque is increased within different time (0.5s, 1s, 2s and 5s). It was shown that, in the transient process mentioned above, engine torque increase time effects fuel economy, smoke opacity and CO emission.
Technical Paper

Optimal Regenerative Braking Control for 4WD Electric Vehicles with Decoupled Electro-Hydraulic Brake System

2015-04-14
2015-01-1117
Regenerative braking control for a four-wheel-drive (4WD) electric vehicle (EV) equipped with a decoupled electro-hydraulic brake system was studied. The energy flow of the 4WD electric vehicle was analyzed during braking, and the brake force distribution strategy between the front-rear axles, regenerative braking and hydraulic braking was studied. Considering ECE R13 regulations, motors and battery pack characteristic constraints, the optimal regenerative braking control strategy using Genetic Algorithm (GA) was proposed. A Hardware-in-loop (HIL) test was built to verify the proposed regenerative braking control strategy. The results show that the optimal regenerative braking control strategy for the 4WD electric vehicle was advantageous over the comparison program, and regenerative energy efficiency reaches 78.87% under the Shanghai Urban Driving Cycle (SUDC).
Technical Paper

Investigation of Control Method for Starting of Linear Internal Combustion Engine-Linear Generator Integrated System

2015-04-14
2015-01-1729
The linear internal combustion engine-linear generator integrated system (LICELGIS) is a generating unit with high power density, high efficiency and low emission for the range-extended electric vehicle. The LICELGIS starts with the linear generator, which shows the advantages of speed, efficiency and emission reduction, as well as the prerequisite to guarantee the steady operation of the system. This paper focuses on the reversing control method and the energy utilization efficiency in the starting process of the LICELGIS. Pursuant to the starting requirements of the linear internal combustion engine, the fewest driving cycle and the evaluation index are obtained. Meanwhile, the velocity tracking mode and the position tracking mode is proposed for the control of the starting force reversing. The motions of the starting process under two control method are comparatively analyzed, indicating that the former has a high efficiency, while the latter is more likely to achieve.
Technical Paper

A Control Allocation Strategy for Electric Vehicles with In-wheel Motors and Hydraulic Brake System

2015-04-14
2015-01-1600
Distributed drive electric vehicle (EV) is driven by four independent hub motors mounted directly in wheels and retains traditional hydraulic brake system. So it can quickly produce driving/braking motor torque and large stable hydraulic braking force. In this paper a new control allocation strategy for distributed drive electric vehicle is proposed to improve vehicle's lateral stability performance. It exploits the quick response of motor torque and controllable hydraulic pressure of the hydraulic brake system. The allocation strategy consists of two sections. The first section uses an optimal allocation controller to calculate the total longitudinal force of each wheel. In the controller, a dynamic efficiency matrix is designed via local linearization to improve lateral stability control performance, as it considers the influence of tire coupling characteristics over yaw moment control in extreme situations.
Technical Paper

Effect of Additives on Diesel Spray Flames in a Controllable Active Thermo-Atmosphere

2008-04-14
2008-01-0931
The active components, such as OH and their concentrations in the coflow, have a strong effect on the combustion process of diesel fuel spray flames in the Controllable Active Thermo-Atmosphere (CATA), which then will affect the soot incandescence of the spray flames. CO2 and H2O2, the additives which have contrary effect on the concentration of the active components, were mixed separately into the thermo-atmosphere before the jet spray were issued into the coflow, which changed the boundary condition around the central jet and influenced the combustion characteristics and soot incandescence. The combustion characteristics such as ignition delay and flame liftoff height of the central spray flames are measured and the linkage between these two parameters is investigated at different coflow temperatures.
Technical Paper

Effect of Piston Crevice on Transient HC Emissions of First Firing Cycle at Cold Start on LPG SI Engine

2007-10-29
2007-01-4015
By changing the top-land radial clearance, this paper presents the effect of the piston crevice on the transient HC emissions of the first firing cycle at cold start on an LPG SI Engine. A fast-response flame ionization detector (FFID) was employed to measure transient HC emissions of the first firing cycle. At the same time, the transient cylinder pressure and instantaneous crankshaft speed of the engine were measured and recorded. The results show that increasing 50% crevice volume leads to 25% increase of HC emissions in the lean region and 18% increase of HC emissions in the rich region, however, the 50% increase of crevice volume contributes to 32% decease of HC emissions in the stable combustion region. For LPG SI engine, the HC emissions of the first firing cycle during cold start are relatively low in a wide range of the excess air ratio.
Technical Paper

Homogeneous Charge Preparation of Diesel Fuel by Spray Impingement onto a Hot Surface at Intake Manifold

2006-10-16
2006-01-3322
A segment of steel tube with the inner diameter of 60 mm and length of 100 mm was fixed between the intake manifold and cylinder head in a direct injection natural aspirated diesel engine. The surface of the tube could be heated to be above 400 °C by the heater enwrapped outside within several minutes under the power less than 600 W. The tip of an injector traditionally used for in-cylinder diesel direct injection was extended to the axis of the tube. The diesel sprays could impinge onto the hot inner surface of the tube and atomize quickly if the temperature of the tube was high enough. Then the fuel-air mixture would be sucked into the cylinder, and HCCI combustion could be fulfilled. The vaporization ratio of the impinged diesel sprays was estimated by fuel consumption, intake air flux and excess air coefficient (λ) calculated from the volumetric concentration of O2, CO2 and CO emissions. The NOx emission was always very low.
Technical Paper

Model Based Yaw Rate Estimation of Electric Vehicle with 4 in-Wheel Motors

2009-04-20
2009-01-0463
This paper describes a methodology to estimate yaw rate of a 4-wheel-drive electric vehicle, in which wheel driven torque can be independently controlled by electric motor. Without non-driven wheels it would be difficult to estimate the vehicle yaw rate precisely, especially when some of the four wheels have large slip ratio. Therefore, a model based estimation methodology is put forward, which uses four wheel speeds, steering wheel angle and vehicle lateral acceleration as input signals. Firstly the yaw rate is estimated through three different ways considering both vehicle kinematics and vehicle dynamics. Vehicle kinematics based method has good estimation accuracy even when the vehicle has large lateral acceleration. However, it can not provide satisfying results when the wheel has large slip ratio. In contrast, vehicle dynamics based method is not so sensitive to wheel slip ratio.
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