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Viewing 31 to 60 of 110594
2017-10-08
Technical Paper
2017-01-2184
Vincenzo De Bellis, Fabio Bozza, Daniela Tufano
Nowadays, the development of a new engine is becoming more and more complex due to conflicting factors regarding technical, environmental and economic issues. Hence, the experimental activity has to comply with the above complexities, resulting in increasing cost and duration of engine development. For this reason, the simulation is becoming increasingly important, thanks to its lower financial burden, together with the need of an improved predictive capability. Among the other numerical approaches, the 1D models represent a proper compromise between reliability and computational effort, especially if the engine behavior has to be investigated over a number of operating conditions. The combustion model has a key role in this contest and the research of consistent approaches is still on going. In this paper, two well-assessed combustion models for Spark Ignition (SI) engines are described and compared: the eddy burn-up theory and the fractal approach.
2017-10-08
Technical Paper
2017-01-2230
Nizar F.O. Al-Muhsen, Guang Hong
Abstract Ethanol as a renewable fuel has been used widely in vehicles. Dual fuel injection which is one of the new techniques in development was adopted to enhance the engine’s thermal efficiency and reduce the emissions. This paper reports an experimental investigation to the ethanol direct injection plus ethanol port injection (EDI+EPI) fuel system with a focus on the effect of spark timing on the engine performance at different ratios of fuel directly injected to fuel port injected (EDI/EPI). Experiments were conducted on a single cylinder 250 cc spark ignition engine at two engine loads, and 3500 RPM. The volumetric ratio of EDI/EPI was varied between EPI (100% port injection) to EDI (100% direct injection) at approximately 25% of the interval. Experimental results showed that the indicated mean effective pressure (IMEP) was improved significantly by up to 20.88% over the entire dual ethanol injection strategy and spark timing.
2017-10-08
Technical Paper
2017-01-2398
Bei Liu, Xiaobei Cheng, Jialu Liu, Han Pu, Li Yi
Based on a 4 cylinder turbocharged diesel engine, the research aims at studying the influence of some the fuel injection timing, fuel injection pressure and the ratio of pilot injection fuel to the engine combustion and emission formation under the condition of single injection and pilot injection ,respectively ,which the main focus on the emission characteristics of particles .The results show that the early-injection PPC formed by single injection can reduce the quantity and quality and GMD of particles obviously. However, when the injection timing is too early, the quantity of particles will rise as normal mode. The effect of injection pressure on particles is significant. The quantity of particles will increase under the condition of PPC, but the quality and GMD of particles is first decrease and the increase. The curve of size distribution of particles displays three peaks shape.
2017-10-08
Technical Paper
2017-01-2409
Erbao Zhang, Yinchun Gong, Jun Deng, Zongjie Hu, Chuanqian Jiang, Zhijun Wu, Liguang Li
Hydrogen fuel will be a potential energy source for internal combustion engines in the future. A promising approach for improving the efficiency and achieving zero-emission is to employ the noble gas argon. The work of this paper aimed at investigating the cyclic variation of argon power cycle engine with fuel of hydrogen. The engine has been modified based on a 0.4 L, one signal cylinder diesel engine into spark ignition engine with a port fuel injection system. The influencing factors on the cyclic variation in the argon power cycle engine with fuel of hydrogen, such as type of working gas, ignition timing, compression ratio (5.6, 6.9, and 7.35), and CO2 fraction in the mixture of argon and oxygen, were test in this study. The results show that compared to air, higher indicated mean effective pressure (IMEP) and better engine operation stability could be achieved under an atmosphere of argon and oxygen.
2017-10-08
Technical Paper
2017-01-2354
Dave Horstman, John Sparrow
Due to recent legislation on CO2 emissions, Heavy Duty OEM’s and their suppliers have had an increased interest in improving vehicle fuel economy. Many aspects are being investigated including vehicle aerodynamics, tire rolling resistance, waste heat recovery, engine fuel efficiency, and many others. Crankcase lubricants offer a cost-effective mechanism to reduce engine friction and increase engine fuel efficiency. The potential gains realized by optimized fuel-efficient lubricants are relatively small, on the order of 1-3%. Therefore, in order to develop these lubricants, formulators must have a robust, repeatable, and realistic test method for differentiation. To address this need, Intertek has been involved with developing fuel economy tests for many years, starting with what became the Sequence VI test for passenger car lubricants in the early 1990’s. Most recently, Intertek has helped develop different FE programs to support the MD and HD diesel industry.
2017-10-08
Technical Paper
2017-01-2358
Michael P Gahagan
The automotive transmission market has seen an increase in the number of hybrid electric vehicles (HEV), and forecasts predict additional growth. In HEVs, the hybrid drivetrain hardware can combine electric motor, clutches, gearbox, electro-hydraulics and the control unit. In HEV hardware the transmission fluid can be designed to be in contact with an integrated electric motor. One transmission type well-suited to such hybridization is the increasingly utilized dual clutch transmission (DCT), where a lubricating fluid is in contact with the complete motor assembly as well as the DCT driveline architecture. This includes its electrics, and therefore raises questions around the suitability of standard transmission fluids in such an application. This therefore drives the need for further understanding of fluid electrical properties in addition to the more usually studied engineering hardware electrical properties.
2017-10-08
Technical Paper
2017-01-2357
Mark Devlin, Jeffrey Guevremont, Chip Hewette, Marc Ingram, Grant Pollard, William Wyatt
Different mechanical components in a vehicle can be made from different types of steel and can even contain different steel alloys or coatings. Lubricant technology is needed to prevent wear and control friction on all of these different surfaces. Phosphorus compounds are the key additives that are used to control wear and they do this by forming tribofilms on surfaces. It has been shown that different operating conditions (pressures and loads) can influence the formation of tribofilms formed by different anti-wear additives. The effect of surface metallurgy and morphology on tribofilm formation is described in this paper. Our results show that additive technology can form proper tribofilms on various surfaces and the right combination of additives can be found for current and future surfaces.
2017-10-08
Technical Paper
2017-01-2361
David R. Lancaster
The auto industry today is a global industry that must conform to local emissions and fuel consumption regulation in virtually all markets. These regulations apply different methodologies to different test cycles. This variation in methodologies and test cycles makes direct comparison of standards difficult. This paper compares the NEDC, WLTC and US EPA driving cycles by examining the tractive energy requirements of vehicles from the 2017 US fleet on each of the cycles. In addition, the mass and footprint data from those vehicles are used to compute the CO2 standards for each vehicle under European, US and Chinese standards.
2017-10-08
Technical Paper
2017-01-2442
Bingqing Xiao, Wei Wu, Jibin Hu, Shihua Yuan, Chenhui Hu
The prediction of temperature distribution and variation of oil-cooled sliding disk pair is essential for the design of wet clutches and brakes in vehicle transmission system. A heat transfer model is established in the study and some fluid-solid coupled heat transfer simulations are performed to investigate the thermal behaviors of wet clutch during sliding. Both cooling liquid and grooved solid disks are contained in the heat transfer model and the heat convection due to the cooling liquid in the radial grooves is also considered by fluid-solid coupled transient heat transfer simulations. The temperature distribution and variation of the grooved disk are discussed and analyzed in detail. The results indicate that the temperature distribution on the grooved disk is nonuniform. The temperature within the middle radius area is higher than that in the inner and outer radius area. The outer radius temperature is higher than the inner radius temperature at the contact face.
2017-10-08
Technical Paper
2017-01-2462
Ruipeng Zhang, Kaichuang Meng
The powertrain of the separated axle hybrid electric dump truck was analyzed, and the vehicle dynamics model was established. Considering the switch among different drive modes during the process of driving, a driving force coordinated allocation control strategy was applied. The control strategy adopts hierarchical structure, the upper layer determines power take-off mode of the vehicle, the middle layer calculates the drive torque of each axle according to its axle load, the lower layer uses PID algorithm to avoid the slip of the drive axle. Control model is established according to the control strategy, combined with the established vehicle dynamic model, co-simulation was conducted. The simulation results show that the driving force coordinated control strategy can adapt to the full load climbing condition and low adhesion road condition, realize the reasonable distribution of driving force and make full use of the ground adhesion.
2017-10-08
Technical Paper
2017-01-2383
Guoyang Wang, Jun Zhang, Bo Yang, Chuandong Li, Shi-Jin Shuai, Shi Yin, Meng Jian
Urea selective catalytic reduction (SCR) is a key technology for heavy-duty diesel engines to meet the increasingly stringent nitric oxides (NOx) emission limits of regulations. The urea water solution injection control is critical for urea SCR systems to achieve high NOx conversion efficiency while keeping the ammonia (NH3) slip at a required level. In general, an open loop control strategy is sufficient for SCR systems to satisfy Euro IV and Euro V NOx emission limits. However, for Euro VI emission regulation, advanced control strategy is essential for SCR systems due to its more tightened NOx emission limit and more severe test procedure compared to Euro IV and Euro V. This work proposed an approach to achieve model based closed loop control for SCR systems to meet the Euro VI NOx emission limits. A chemical kinetic model of the SCR catalyst was established and validated to estimate the ammonia storage in the SCR catalyst.
2017-10-08
Technical Paper
2017-01-2326
Ang Li, Zhiwei Deng, Lei Zhu, Zhen Huang
In the present study a novel surrogate model for biodiesel including methyl decanoate (MD) and methyl crotonate (MC) was proposed and validated. In the binary mixture of surrogate fuel, MD was chosen to represent saturated methyl esters, which exhibited great low-temperature reactivity with typical negative temperature-coefficient (NTC) behavior and MC represented unsaturated components in real biodiesel, which was mainly responsible for soot formation and evolution. The proportion of MD and MC was determined by matching the characteristics such as derived cetane number (DCN), molecular weight (MW), atom number, H/C ratio and unsaturated degree. All of the criterions were calculated by the least square principles and the calculated surrogate of biodiesel was comprised of 92% MD and 8% MC in mole fraction. Furthermore, detailed kinetic model of the surrogate fuel was constructed and developed with modifications, which was composed of 2918 species and 9164 reactions.
2017-10-08
Technical Paper
2017-01-2347
Kazushi Tamura, Kenji Sunahara, Motoharu Ishikawa, Masashi Mizukami, Kazue Kurihara
Modern lubricants such as fuel economy engine oils control friction through tribofilms formed by functional additives mixture. Although many cases on synergistic or antagonistic effects of additives on friction have been reported, their mechanisms are poorly understood. Here we found that some of the detergent additives with metallic soap reduced friction synergistically with molybdenum dithiocarbamate (MoDTC), which is a widely-used friction modifier additive that forms slippery tribofilm, while detergents themselves increased friction without MoDTC. These results indicate that detergents enhance friction-induced formation of slippery tribofilms by MoDTC. To reveal this mechanism, using surface force apparatus equipped with a resonance shear measurement system (SFA-RSM), we examined mechanical properties of detergent-containing oils confined at single-asperity contact.
2017-10-08
Technical Paper
2017-01-2292
George S. Dodos, Florentia Vassileiou, Dimitrios Karonis
Lubricity is considered as one of the fundamental quality parameters of diesel fuel since several diesel engine parts, such as pumps and injectors, are lubricated by the fuel itself. The dramatic reduction of sulfur content in diesel fuel leads to the elimination of heterocyclic compounds that are beneficial to lubricity. As a result especially in ultra low sulfur diesel the lubricating efficiency has to be fulfilled by the contained hydrocarbons. Therefore, it is very interesting to know to what extend each type of hydrocarbon contributes to diesel fuel lubricity when neither FAME nor a lubricity improver is employed. The aim of this study is to investigate the lubricity of hydrocarbons that constitute components of petroleum diesel fuel. A number of typical hydrocarbon compounds were selected as representatives of the group types of paraffins, olefins, cycloparaffins and aromatics, similar to those that are present in diesel fuel.
2017-10-08
Technical Paper
2017-01-2334
Chrysovalanti E. Tsesmeli, George S. Dodos, Fanourios Zannikos
Biodiesel (Fatty Acid Methyl Esters) is found to be more prone to oxidative deterioration compared to conventional diesel fuel. In order to guarantee the fuel storage stability, the introduction of antioxidant agents is usually necessary. On the other hand, biodiesel is also associated with microbial growth issues due to its hygroscopic characteristics and its chemical composition leading to fuel bio-deterioration. The aim of this study is to investigate the effect of a variety of phenolic type antioxidant additives on biodiesel and diesel/ biodiesel microbial stability. Five synthetic phenolic type antioxidant agents were added in FAME at concentrations up to 1000 ppm. Treated FAME was also blended with Ultra Low Sulphur Diesel (ULSD) fuel at a concentration of 7% v/v in order to examine the activity of the substances in the final blends.
2017-10-08
Technical Paper
2017-01-2201
Zhongye Cao, Tianyou Wang, Kai Sun, Lei Cui, Yong Gui
For uniflow scavenged two-stroke marine diesel engines, the main function of scavenging process is to replace the burned gas with fresh charge. The end state of scavenging process is integral to the subsequent compression and combustion, thereby affecting the engine’s fuel economy, power output and emissions. In this paper, a complete working cycle of a large marine diesel engine was simulated by using the 3D-CFD software CONVERGE. The model was validated by mesh sensitivity test and experiment data. Based on this calibrated model, the influences of swirl ratio and exhaust valve closing (EVC) timing on the scavenging process were investigated. The parameters evaluating the performance of scavenging process were introduced. The results show that, by adjusting the swirl orientation angle(SOA) from SOA=10° to SOA=30°, different swirl ratios are generated and have obvious differences in flow characteristics and scavenging performance.
2017-10-08
Technical Paper
2017-01-2190
Alessandro D'Adamo, Marco Del Pecchia, Sebastiano Breda, Fabio Berni, Stefano Fontanesi, Jens Prager
CFD simulations of reacting flows are fundamental investigation tools used to predict combustion behaviour and pollutants formation in modern spark-ignition internal combustion engines. Most of the flamelet-based combustion models adopted in current simulations use the fuel/air/residual laminar flame speed as a background to predict the turbulent flame speed. This in turn is a fundamental requirement to model the effective burn rate. The consolidated approach in engine combustion simulations relies on the adoption of empirical correlations for laminar flame speed, which are derived from fitting activity of combustion experiments. However, these last are conducted at largely different pressure and temperature ranges from those encountered in engines: for this reason, correlation extrapolation at engine conditions is inevitably accepted and relevant differences between proposed correlations emerge even for the same fuel and conditions.
2017-10-08
Technical Paper
2017-01-2236
Mateos Kassa, Carrie Hall, Fabien Vidal-Naquet, Thomas Leroy
In this study, the impact of the intake valve timing on knock propensity is investigated on a dual-fuel SI engine leveraging a low octane fuel and a high octane fuel to adjust the fuel mixture’s octane rating (RON) based on operating point. Variations in the intake valve timing have a direct impact on residual gases concentration due to valve overlap and changes in the compression pressure and temperature due to variations of the effective compression ratio. In this study, it is shown that the fuel RON requirement for a non-knocking condition at a fixed operating point can vary significantly solely due to variations of the intake valve timing. The fuel RON requirement at 2000 rpm and 6 bar BMEP ranges between 80 to 90 as a function of VVT, and between 98 to 104 at 2000 rpm and 14 bar BMEP.
2017-10-08
Technical Paper
2017-01-2186
Lukas Urban, Michael Grill, Sebastian Hann, Michael Bargende
The development of IC engines is a complex process where 0D/1D-simulation tools became more important in the past few years. Different designs can be investigated in very early stages of the development process without the expensive buildup of prototypes and it is possible to get reliable results with passable effort. The quality of the overall simulation results depends on the quality of the sub-models. Simulation of the combustion process in natural-gas SI engines relies on predictive models for burn rates and knock. Existing knock models for gasoline fuels are based on a time-integrated ignition delay, using a fitted Arrhenius equation. Within a research project an enhanced knock-model approach for methane based fuels was developed. Chemical kinetics models were used to calculate the auto-ignition times for various temperatures, pressures and air-fuel-ratios (AFR).
2017-10-08
Technical Paper
2017-01-2350
Chalermwut Wongtaewan, Umaporn Wongjareonpanit, Komkrit Sivara, Ken Hashimoto, Yoichiro Nakamura
In Thailand, most heavy-duty trucks were equipped with diesel engine, while a small portion was equipped with compressed natural gas (CNG) engine. However, in the past few years the number of CNG fuel trucks in Thailand has increased significantly due to the cheaper cost of CNG. In general, the emphasis of heavy-duty diesel engine oil performance is on piston cleanliness and soot handling properties, while thermal and anti-oxidation properties are most critical for CNG engine oil performance. For truck fleet owners who operate both types of trucks, using the inappropriate oil that is not fit-for-purpose can adversely affect engine performance and reduce engine service lifespan under prolonged usage. A novel CNG/diesel engine oil has developed by PTT to meet both JASO DH-2 performance for heavy-duty diesel engine oils and OEM requirements for CNG engine oils.
2017-10-08
Technical Paper
2017-01-2252
Weihua Sun, Wei Du, Xuefei Dai, Xiangdong Bai, Zhiping Wu
Getting real cylinder pressure is the basis of engine combustion analysis. Because of the advantages of good thermal performance, fast response, small size, high accuracy, large range and so on, piezoelectric quartz sensor is widely used in the measurement of the cylinder pressure. But this kind of sensor can only get the dynamic cylinder pressure which may not represent the real one. In this situation, the cylinder pressure needs to be corrected by some method. It also could cause great result divergences of the combustion analysis by using different cylinder pressure correction methods. This paper aims to acquire a proper cylinder pressure correction method by carrying out the theory analysis based on ideal gas equation and experiment research of cylinder pressure on a turbocharged eight-cylinder diesel engine.
2017-10-08
Technical Paper
2017-01-2247
Wenbin Zhang, Haichun ding, Shijin Shuai, Bin Zheng, Alex Cantlay, Vinod Natarajan, Zhang Song ZHAN, Yunping Pu
Gasoline direct injection (GDI) engines have been developed rapidly in recent years, driven by stringent legislative requirements on vehicle fuel efficiency and emissions. However, one challenge facing GDI is the formation of particulate emissions, particularly with the presence of injector tip deposits. The Chinese market features some gasoline fuels that contain no detergent additives and are prone to deposit formation, which can affect engine performance and emissions. The use of detergent additives to mitigate the formation of injector deposits in a GDI engine was investigated in this study by testing a 1.5L turbocharged GDI engine available in the Chinese market. The engine was operated both on base gasoline and on gasoline dosed with detergent additives to evaluate the effect on injector deposit formation and engine performance and emissions.
2017-10-08
Technical Paper
2017-01-2460
Wenbin Liu, Qiang Song, Yiting Li, Wanbang Zhao
In this paper, a novel driver model is proposed to track vehicle speed in MIL (Model-in-the-Loop) test system, which has structural consistency with HIL (Hardware-in-the-Loop) test system. First, the MIL test system which contains models of driver, vehicle and test bench is established. Second, according to the connections of the established models in Matlab/Simulink environment, the vehicle speed is calculated in vehicle model. Emphatically, through the deviation between driving cycle speed and calculated vehicle speed, PI controller in driver model adjusts the vehicle speed to ideal point through sending the torque command to drive motor, the ILC (Iterative Learning Control) controller modifies and stores P value of PI controller. Then, in order to obtain the better modification of PI controller, iterative learning control algorithm is deeply researched in term of types and parameters.
2017-10-08
Technical Paper
2017-01-2333
Marcos Gutierrez, Andres Castillo, Juan Iniguez, Gorky Reyes
The aim for cleaner and more efficient energy from the internal combustion engines makes necessary to ensure the conditions for the exploitation of alternative fuels. The vibrations on engines are primarily understood as effects of mechanical failures, but the engine vibration is subject of the fuel combustion effects too. This effects will depend on the fuel type and its capacity to be burned. The vibrations of a diesel engine were measured and analyzed with a frequency spectrum calculated with Fast Fourier Transforms. The engine was operated with a fuel blend from 10 % recycled lubricating oil with 90% diesel as well as only diesel. It was found the engine operation with this fuel blend has a lower vibration level in comparison with the use of pure diesel. The goal of this research is to determine the properties of the fuel blend, which provides more stability to the engine by means of vibrations reduction.
2017-10-08
Technical Paper
2017-01-2388
Ahmad Khalfan, Gordon Andrews, Hu Li
The emissions from vehicles in real world driving are of current concern, as they are often higher than on legislated test cycles and this may explain why air quality in cities has not improved in proportion to the reduction in automotive emissions. This has led to the Real Driving Emissions (RDE) legislation in Europe. RDE involves journeys of about 90km with roughly equal proportion of urban, rural and motorway driving. However, air quality exceedances occur in cities with urban congested traffic driving as the main source of the emissions that deteriorate the air quality. Thus the emissions measured on RDE journeys may not be relevant to air quality in cities. A Temet FTIR and Horiba exhaust mass flow measurement system was used for the mass emissions measurements in a Euro 4 SI vehicle. A 5km urban journey on a very congested road was undertaken 29 times at various times so that different traffic congestion was encountered.
2017-10-08
Technical Paper
2017-01-2193
Andreas Nygren, Anders Karlsson
When developing new combustion concepts, CFD simulations is a powerful tool. The modeling of spray formation is a challenging but important part when it comes to CFD modelling of non-premixed combustion. There is a large difference in the accuracy and robustness among different spray models and their implementation in different CFD codes. In the work presented in this paper a spray model, designated as VSB2 has been implemented in OpenFOAM. VSB2 differ from traditional spray models by replacing the Lagrangian parcels with stochastic blobs. The stochastic blobs consists of a droplet size distribution rather than equal sized droplets, as is the case with the traditional parcel. The VSB2 model has previously been thoroughly validated for spray formation and combustion of n-heptane. The aim of this study was to validate the VSB2 spray model for ethanol spray formation and combustion as a step in modelling dual-fuel combustion with alcohol and diesel.
2017-10-08
Technical Paper
2017-01-2415
Valery Dunaevsky
The film thickness–roughness ratio Λ has been used since the mid-1960s as a criterion for the lubrication conditions in rolling bearings. However, due to an assumed Gaussian distribution of the roughness height amplitudes of the functional surfaces of rolling bearings and other unsubstantiated assumptions concerning the mechanisms of contact interaction, concerns have arisen about the representability of Λ in terms of lubrication. In this study, a more objective Λ-type ratio that does not depend on the law of roughness height distribution and the peculiarities of contact mechanics is introduced and defined as Λz. The relevant range of the new Λ ratio, which identifies a full-film lubrication, is lower than that of its conventional counterpart, and it coincides directionally with contemporary theoretical and experimental results. The study exhibits unique profilometric data of the functional surfaces of the roller bearings, produced by the major bearing manufacturers.
2017-10-08
Technical Paper
2017-01-2226
Edward S. Richardson, Michael J. Gill, Mathew Middleton, Bruno S. Soriano
Cylinder deactivation enables improvements in fuel economy in spark-ignition engines by reducing pumping losses during part load operation. The efficiency benefits of a new intake valve system that enables cycle-by-cycle deactivation of different cylinders is investigated in this study. The system minimises the need for throttling by varying the fraction of strokes that are deactivated in order to vary engine output. The intake valve system involves two intake valves in series, with a fast solenoid-actuated valve upstream of a conventional cam-actuated intake valve. Compared to conventional cam-actuated valves, the new valve system has potential to achieve very rapid closing rates with a high degree of flexibility in respect of the timing of inlet valve closure. The fuel economy benefits provided by a number of valve control strategies are evaluated using a one-dimensional modelling approach, considering a vehicle following the New European Drive Cycle.
2017-10-08
Technical Paper
2017-01-2414
Dongsheng Zhang, Qilong Lu, Michael Kocsis, Ian Gilbert, Marc Megel, Xihao Liu, Jiaxin Gu, Qingyan Liu, Yanming He
The new BAIC engine, an evolution of the 2.3L 4-cylinder turbocharged PFL gasoline from Saab, was designed, built, and tested with close collaboration between BAIC Motor Powertrain Co., Ltd (BMPC) and Southwest Research Institute (SwRI). The upgraded engine was intended to achieve low fuel consumption and a good balance with high performance and compliance with Euro 6 emissions regulation. Low fuel consumption was achieved primarily through utilizing cooled low pressure loop exhaust gas recirculation (LP-EGR) and dual independent cam phasers, improving intake and exhaust design, optimizing combustion chamber design, and minimizing mechanical friction losses. Cooled LP-EGR helped suppress engine knock and consequently increase compression ratio and improve thermal efficiency of the new engine. Dual independent cam phasers reduced engine pumping losses and helped elevate low-speed torque.
2017-10-08
Technical Paper
2017-01-2239
Andreas F. G. Glawar, Fabian Volkmer, Pauline R. Ziman, Adrian P. Groves, Roger F. Cracknell
Port fuel injected (PFI) technology remains the most common fuel delivery type present in the marketplace for gasoline spark ignition engines. Although increasingly stringent tailpipe CO2 targets in some markets are driving the industry towards more efficient direct injection (DI) technology, in the light of ever increasing vehicle lifetimes, a legacy vehicle fleet featuring PFI technology will remain in the marketplace for decades to come. This is especially the case in some Asian markets where PFI technology is still prominent, although DI technology adoption is starting to catch up. PFI engines can, in the presence of lower quality fuels and lubricants, build up harmful deposits on a range of critical engine parts including in the fuel injectors, combustion chamber and on inlet valves. Inlet valve deposits (IVDs) in more severe cases have been associated with drivability issues such as engine stumble and engine hesitation on sudden acceleration.
Viewing 31 to 60 of 110594