Search Results

The emission and flow restriction characteristics of three different ceramic substrates with varying wall thickness and cell density (400 cpsi/6.5 mil, 600/4.3, and 600/3.5) are compared. These 106mm diameter substrates were catalyzed with similar amounts of washcoat and fabricated into catalytic converters having a total volume of 2.0 liters. A Pd/Rh catalyst technology was applied at a concentration of 6.65 g/l and a ratio of 20/1. Three sets of converters (two of each type) were aged for 100 hours on an engine dynamometer stand. After aging, the FTP performance of these converters were evaluated on an auto-driver FTP stand using a 2.4L, four-cylinder prototype engine and on a 2.4L, four-cylinder prototype vehicle. A third set of unaged converters was used for cold flow restriction measurements and vehicle acceleration tests.

In this project, phenomena in a SCR catalyst, such as heat transfer and catalytic reactions, are modeled numerically. The model is simplified to be integrated on an electronic control unit. The calibration process for this model has been developed, which is performed on gas bench and validated on a vehicle equipped with a Urea-SCR system and a Rapid Prototype Control Unit. With this simplified SCR reaction model, it is possible to estimate NH3 consumption and properly control the urea injection quantity with less calibration efforts.

Close coupled catalysts and new ceramic catalyst substrates have significantly improved the light-off performance of automotive converters required to meet stringent emission requirements. The hotter environment of these catalytic converters and the lower structural strength of the ceramic substrates require the rethinking of converter designs. The development of new package requirements to accommodate the change in environment and new substrates are discussed. A historical perspective on converter durability is presented as reference. Development of durability test protocols is essential to verifying product durability performance to these new environments. Data collection and documentation of testing templates are shown to demonstrate the effectiveness of tests that represent real world environments. Design improvements to address failure modes are discussed along with durability improvement results.

This study presents engine test results of HMC's piston-ported 2-stroke gasoline engine. This single cylinder engine of 400cc displacement has featured in direct injection(DI) of fuel and external blower scavenging of air. Two different concepts of DI system were adopted, one is high pressure fuel injection(HPFI) system for solid fuel only and the other is low pressure air-assisted fuel injection(AAFI) system. Two kinds of engines with different scavenging intake port shapes and areas were tested to find the effect of scavenging port type on engine performance. Also tested were trends of BSFC, BSHC and BSCO versus fuel injection timing and engine speed with HPFI and AAFI, respectively. Power and boost pressure at full load and BSFC and BSHC at part load were tested.

A new concept of misfire detection in spark ignition engines using a wide-range oxygen sensor is introduced. A wide-range oxygen sensor, installed at the confluence point of the exhaust manifold, was adopted to measure the variation in oxygen concentration in case of a misfire. The signals of the wide-range oxygen sensor were characterized over the various engine-operating conditions in order to decide the monitoring parameters for the detection of the misfire and the corresponding faulty cylinder. The effect of the sensor position, the transient response characteristics of the sensor and the cyclic variation in the signal fluctuation were also investigated. Limited response time of a commercially available sensor barely allowed to observe misfire. It was found that a misfiring could be distinguished more clearly from normal combustion through the differentiation of the sensor response signal. The differentiated signal has twin peaks for a single misfiring in a cylinder.

Delphi Diesel Systems (DDS) - Heavy Duty Business is developing a new range of Ultra High Pressure Common Rail Fuel Injectors with the functionality to allow the combustion heat release to be heavily adapted during operation. This allows the injector performance to be simultaneously optimised across a broad range of engine conditions, removing the constraints of having to select a single rate shape type for all operating conditions. This new technology range builds on the performance of Delphi's 2700 bar Fuel Systems of F2E, F2P and F2R, whilst adding in new levels of injector control, beyond what is available in the current market. In addition to this new functionality, Delphi's new Heavy Duty Injector range also demonstrates greatly reduced leakage and improved accuracy of fuel control. This paper reviews the benefits and possibilities of this new injector technology.

Wide varieties of vehicle Engine Management Systems are designed by different Tier#1 suppliers to meet highly complex requirements with the help of electronics. Emerging technologies and features of Engine Management Systems require a number of strategies for reducing the overall timing for verification with high quality testing. Analysis and decoding of data especially for highly critical and complex such as gasoline direct injection (GDi) engine fuel delivery output, high pressure fuel pump (HPFP), spark control output and different varieties of engine position signals are time consuming. This paper introduces Virtual Engine Control Module (VECM) technology to solve the problem of decoding complex signals and high level verification. A proposed test bench setup consists of VECM, ECM, simulator and real actuator load with complete software flashed inside the ECM.

Similar to single-brick SCR architectures, the multi-brick SCR systems described in this paper require urea injection control software that meets the NOx conversion performance target while maintaining the tailpipe NH3 slip below a given threshold, under all driving conditions. The SCR architectures containing a close-coupled SCRoF and underfloor SCR are temperature-wise more favorable than the under-floor location and lead to significant improvement of the global NOx conversion, compared to a single-brick system. But in order to maximize the benefit of close-coupling, the urea injection control must maximize the NH3 stored in the SCRoF. The under-floor SCR catalyst can be used as an NH3 slip buffer, lowering the risk of NH3 slip at the tailpipe with some benefit on the global NOx conversion of the system. With this approach, the urea injection strategy has a limited control on the NH3 coverage of the under-floor SCR catalyst.

Most current flex-fuel vehicles are capable of operating on gasoline/ethanol blends from E0 to E85. The presence of gasoline in the fuel enables cold startability because some of its more volatile components can still vaporize at cold temperatures and produce an ignitable mixture. However when E100 is used, other means are required for cold starting because of ethanol's relatively low vapor pressure at low temperatures. A common technique is to employ an auxiliary gasoline fuel system for use only when temperatures are too low for the vehicle to start on E100 alone. But the added cost, complexity and maintenance of such systems have driven the search for a simpler approach. One such technique is to heat the fuel prior to injection. Fuel systems currently exist where heating occurs within the main conduit of the fuel rail. Another method is to heat the fuel within each fuel injector.

Most current automotive and light truck fuel level sensors are essentially rotary potentiometers that have been designed to survive the chemically harsh environments found in the fuel tank. This paper will chronicle the design improvements made from the early wire wound versions to today's more robust thick film ink systems. The paper will highlight potential failure modes and discuss techniques to reduce noise and increase wear life. Data will be provided regarding changes in the circuit layout, ink compositions, and contact materials. Special consideration will be given to the adverse effects associated with the reactive sulfur prevalent in today's fuels.

To satisfy the global fuel economy restrictions getting stricter, various advanced cooling concepts, like active flow control strategy, cross-flow and fast warm-up, have been applied to the engine. Recently developed Hyundai’s next generation 4-cylinder 2.0L gasoline engine, also adopts several new cooling subsystems. This paper reviews how 3-D CAE analysis has been extensively used to evaluate cooling performance effectively from concept phase to pre-production phase. In the concept stage, the coolant flow in the water jacket of cylinder head and block was investigated to find out the best one among the proposed concepts and the further improvement of flow was also done by optimizing cylinder head gasket holes. Next, 3-D temperature simulation was conducted to satisfy the development criteria in the prototype stage before making initial test engines.

A new exhaust system has been developed to cope with post-SULEV (Super Ultra-Low Emissions Vehicle) regulation by newly designed hardware of exhaust system. This paper will describe the various new technologies used for achieving the post-SULEV standards, such as Conicat (cone-type metal catalyst), dual-wall pipe, pipe-type metal catalyst, ultra thin wall monolith and HC trap system for the improvement of catalyst light-off time. The tested data on 2.0L SULEV vehicle indicate that Conicat(cone-type metal catalyst) and HC trap (hydrocarbon absorbing catalyst) have more positive characteristics, and are expected to show the enhanced HC reduction performance with the optimization of emission system.

It is difficult to reach higher compression ratios of the gasoline engine even though higher compression ratios improve thermal efficiency. One of the barriers is large torque drop led by knocking. Extensive researches to suppress knocking of the gasoline engine have been conducted. It is focused on lowering the temperature of fuel mixture in combustion chamber at compression top dead center (TDC). This paper covers the new valvetrain system to decrease the temperature of exhaust valve bottom (combustion) side. Hollow head and stem sodium filled valve (HHSV) have shown more heat transfer from combustion chamber to valve seat insert and valve guide, and higher thermal conductivity valve seat insert (HVSI) and valve guide (HVG) help to decrease valve temperature lower by higher heat transfer.

In previous work, Gasoline Direct Injection Compression Ignition (GDCI) has demonstrated good potential for high fuel efficiency, low NOx, and low PM over the speed-load range using RON91 gasoline. In the current work, a four-cylinder, 1.8L engine was designed and built based on extensive simulations and single-cylinder engine tests. The engine features a pent roof combustion chamber, central-mounted injector, 15:1 compression ratio, and zero swirl and squish. A new piston was developed and matched with the injection system. The fuel injection, valvetrain, and boost systems were key technology enablers. Engine dynamometer tests were conducted at idle, part-load, and full-load operating conditions. For all operating conditions, the engine was operated with partially premixed compression ignition without mode switching or diffusion controlled combustion.

Fuel systems associated with Gasoline Direct Injection (GDi) engines operate at pressures significantly higher than Port Fuel Injection (PFI) engine fuel systems. Because of these higher pressures, GDi fuel systems require a high pressure fuel pump in addition to the conventional fuel tank lift pump. Such pumps deliver fuel at high pressure to the injectors multiple times per engine cycle. With this extra hardware and repetitive pressurization events, vehicles equipped with GDi fuel systems typically emit higher levels of audible noise than those equipped with PFI fuel systems. A common technique employed to cope with pump noise is to cover or encase the pump in an acoustic insulator, however this method does not address the root causes of the noise. To contend with the consumer complaint of GDi system noise, Delphi and Magneti Marelli have jointly developed a high pressure fuel pump with reduced audible output by concentrating on sources of noise generation within the pump itself.

FTP emissions from a 2.2L four cylinder vehicle are measured from six different converters. These converters have been designed to have both similar flow restriction and to have similar platinum group metals. The durability of these six converters is evaluated after dynamometer aging of both 125 and 250 hours of RATsm aging. These catalytic converters use various combinations of 400/3.5 (400 cells/in2/3.5mil wall), 400/4.5, 400/6.5, 600/3.5, 600/4.5, and 900/2.5 ceramic substrates in order to meet a restriction target and to maximize converter geometric surface area. Total catalyst volume of the converters varies from 1.9 to 0.82 liters. Catalyst frontal area varies from 68 cm2 to 88 cm2. Five of the six converters use two catalyst bricks. The front catalyst brick uses either a three-way Pd washcoat technology containing ceria or a non-ceria Pd washcoat technology. To minimize dependence on palladium the rear brick uses a Pt/Rh washcoat at a loading of 0.06 Toz and a ratio of 5/0/1.

After the second worldwide oil crisis, Brazil put in place by 1975 a strategic plan to stimulate the usage of ethanol (from sugar cane), to be mixed to the gasoline or to be sold as 100% ethanol fuel (known as E100). To enable an engine to operate with both gasoline and ethanol (and their mixtures), by 2003 the “Flex Fuel” technology was implemented. By 2012 calendar year, from a total of about 3.8 million vehicles sold in the Brazilian market, 91% offered the “Flex Fuel” technology, and great majority used a gasoline sub-tank to assist on cold starts (typically below 15°C, where more than 85% of ethanol is present in fuel tank). The gasoline sub-tank system suffers from issues such as gasoline deterioration, crash-worthiness and user inconvenience such as bad drivability during engine warm up phase. This paper presents fuel injector technologies capable of rapidly electrically heating the ethanol fuel for the Brazilian transportation market.

A nano-sized PM and THC emission characteristics were investigated according to the fuel injection strategy such as a pressure and timing in the GDI engine. On the part-load condition, the particulate emissions exhibited a strong sensitivity to the injection timing. The fuel injection pressure also had a great association with the nano-particles and THC. A size of PM exhausted from the GDI engine located near 10nm on the part-load. In contrast, accumulation mode particles within 60 - 80nm mainly exhausted during the cold transient start phase. Increment of fuel injection pressure positively affected on the nano-particle and THC emissions during the start of the engine, as well.

Delphi Diesel Systems' 2700bar Proven F2E Distributed Pump Common Rail System (DPCRS) has been developed to meet the requirements of Euro VI and future emissions legislation and is now in volume production in Heavy Duty Vehicles. Incorporating a number of ground breaking new technologies, the system offers numerous performance advantages. F2E provides full common rail functionality for camshaft driven Fuel Injection Equipment (FIE) engines with minimum modification. By delivering precise and accurate control of multiple injections at maximum rail pressure across all engine operating conditions, the system minimizes the demands on exhaust after treatment systems. Additionally F2E provides real time flexible capacity by employing a unique method of pump fuel metering, enabling the most efficient and accurate transient control of rail pressure combined with the low NVH and optimised efficiency.

In this research, an optical system for the detection of the flame propagation under the non-knocking and knocking conditions is developed and applied to a mass produced four cylinder SI engine. The normal flames are measured and analyzed under the steady state operating conditions at various engine speeds. For knocking cycles, the flame front propagations before and after knock occurrence are simultaneously taken with cylinder pressure data. In non-knocking and knocking cycles, flame propagation shows cycle-by-cycle variations, which are quite severe especially in the knocking cycles. The normal flame propagations are analyzed at various engine speeds, and show that the flame front on the exhaust valve side becomes faster as the engine speed increases. According to the statistical analysis, knock occurence location and flame propagation process after knock can be categorized into five different types.