On-board diagnostics, required by governmental regulations, provide a means for reducing harmful pollutants into the environment. Since being mandated in 1996, the regulations have continued to evolve and require engineers to design systems that meet strict guidelines. This one day seminar is designed to provide an overview of the fundamental design objectives and the features needed to achieve those objectives for generic on-board diagnostics. The basic structure of an on-board diagnostic will be described along with the system definitions needed for successful implementation.
With increasing pressure from environment problem for reduction in CO2 emissions and stricter fuel targets from road vehicles, OEM around the globe have to electrification their vehicle range to meet increasingly challenging emission standards in recent years and new transmission technologies are gaining more attention in different main market . The actual and future powertrain development has three major directions in order to reduce or avoid emissions in the transportation sector: Hybrid Vehicles: Hybrid Electric Vehicles (HEV), Plug-in HEV (PHEV) Electric Vehicles (EV); Range Extender Electric Vehicle (REEV); Fuel Cell Electric Vehicles (FCEV), Range Extender FCEV (REFCEV). This paper will presents a new type Hybrid transmission which so called “DHT (Dedicated Hybrid Transmission) “ technology for cost-effective HEVs and PHEVs is to permit the design of very compact automatic transmissions with an integrated high-voltage electric motor on the output side of the transmission.
Plug-in hybrid electric vehicles (PHEVs) combine some of the attractive traits of both fully electric vehicles (EVs) and non-plug-in hybrid vehicles (HVs). EV traits shared by PHEVs include the capability to charge the battery via electricity from the grid while the vehicle is parked and the ability to drive an appreciable distance without having to turn the engine on, in what is known as charge depletion mode. HV traits shared by PHEVs include the ability to use the engine to maintain the state of charge (SOC) of the batteries within certain limits, in what is known as charge sustaining mode. Charge sustaining mode allows a PHEV to not be limited by battery charging time when undergoing long distance travel (unlike EVs), but comes at the trade-off in that gas (or more generally, any fuel) needs to be used, similar to an HV.
IC engines are most efficient when they operate steadily in specific zones which cannot be attained in real driving conditions. Hybrids tackle this issue and improve drivetrain efficiency. Though they are used in cars and commercial vehicles they do not find application in small two wheelers especially scooters which constitute the majority of the market in several Asian Countries. The reasons are cost of implementation and need to have a suitable design. Integrating an electric motor with a conventional scooter drivetrain while retaining the base engine and the CVT is a cost effective proposition which is the motivation behind this work. Such a development will need accounting for the behavior of the belt driven CVT. In this paper a comparison between two parallel hybrid layouts has been made with the base 110cc scooter powertrain. A map based engine model and a physics based CVT model were developed and validated to simulate the base drive-train on the WMTC drive-cycle.
Natural Gas used in high-efficiency engines holds promise as a low-cost intermediate solution to reduce Greenhouse Gases and particulate matter. However, to achieve high engine efficiencies, engines need to be operated at higher power levels and increased Brake Mean Effective Pressures (BMEP), which is limited by destructive, engine damaging knock. Alternatively, if controlled, the same End-Gas Autoignition (EGAI) process responsible for knock can boost efficiencies and consume unburned methane while leveraging low-cost traditional exhaust aftertreatment technologies, such as a three-way catalyst, to minimize environmental impact. For this reason, this work has developed a method to detect the presence of EGAI and to determine its onset location (or crank angle).
Ever restrictive emissions legislations and fuel efficiency targets have been posing challenges for engine development. Knocking is aloways a limiting factor for spark-ignited engines and has to be tighly controlled during the development phase. There are several methods that address how to detect and measure its occurense. They often require complex calculations with high computational costs that limit them only to laboratorial operation. Moreover, they are often calibrated with subjective factors, for each engine. Thus, this paper offers a novel process that is simpler and does not require previous calibration, called G Index. It is based on the angular position of the peak of maximum pressure rise rate and its relation to the 50% mass fraction burn angular possition. The results showed that there is a locus of knock-free operation with GI between -10 and 0.
Research on alternative fuels has made significant progress as demands for cleaner and efficient engine operation intensifies. Liquefied petroleum gas (LPG) can offer a potential alternative fuel route in the Diesel fuel dominated heavy-duty transportation sector due to its low cost, high anti-knock limit relative to gasoline, and reduced emission levels. In this work, experimental investigations are performed to study the effects of LPG compositions on performance, emissions, and combustion behavior of a cooperative fuel research (CFR) engine under stoichiometric conditions. Four LPG blends (chemically pure propane, a representative US blend, HD5, and a representative European blend) representing the present LPG market are chosen. The impact of fuel composition is studied under different compression ratios (CR) ranging from 7:1 to 10:1 with one-unit increments. The results show that fuel composition has minimal effect on engine efficiency over the CR range.
Hydrogen engines offer the possibility of a carbon neutral transportation – a focal point of current propulsion development activities especially for EU and US future concepts. From today's point of view, hydrogen can play an important role in this regard as it is a carbon-free fuel, no CO2 emissions are produced during its combustion process. Besides, it can be well used for lean burn combustion leading to very low NOx emissions, a key benefit in combination with an optimized after-treatment system for future ultra-low NOx legislations of heavy-duty (HD) engines. Comprehensive investigations using single-cylinder tests and model-based development approach are performed aiming the definition of a high efficiency hydrogen engine concept. An optimization regarding compression ratio and engine calibration (regarding AFR, EGR rates and optimal combustion phase) is carried out while considering knocking.
It is well established that reducing the compression ratio (CR) of a diesel engine leads to a significant increase in hydrocarbon (HC) and carbon monoxide (CO) emissions, especially in cold and transient conditions. For the same reason, utilizing low compression ratio (LCR) diesel engines is severely limited in automotive applications worldwide that demand compliance of tailpipe emissions in defined transient regulatory cycles like modified Indian drive cycle (MIDC). Hence, it is essential to find new strategies to improve the HC and CO emissions of an LCR diesel engine in transient conditions. In the present work, a detailed evaluation of different warm-up technologies was conducted for their effects on transient emissions characteristics of a single-cylinder naturally aspirated LCR diesel engine. For this purpose, the engine was coupled to an instrumented transient engine dynamometer set-up.
To comply with increasingly stringent pollutant emissions regulations, catalyst-heating operation in diesel engines is critical to achieve rapid light-off of exhaust aftertreatment catalysts during the first minutes of cold starting. Current approaches to catalyst-heating operation typically involve one or more late post injections to retard combustion phasing and increase exhaust temperatures. The ability to retard post injection timing while maintaining acceptable pollutant emissions levels is pivotal for improved catalyst-heating calibrations. Fuel cetane rating has been reported to enable later post injections with increased exhaust heat and decreased pollutant emissions, but the mechanism by which this occurs is not well understood. The purpose of this experimental study is to provide further insight into the ways in which fuel cetane rating affects combustion and pollutant formation in a medium-duty diesel engine.
The shift towards electrification, and the limitations in battery electric vehicle technology have led to high demand for hybrid vehicles (HEVs), employing a combination of battery and internal combustion engine for propulsion. Although, HEVs enable lower fuel consumption and emissions compared to conventional vehicles, they still employ combustion of fuels for IC engine operation and thus emissions from hybrid vehicles are still a major concern. Engine starts are one of the major sources of emissions during any driving event especially before the three-way catalyst (TWC) has reached light-off temperature. Since, the engine is subjected to multiple starts in most of driving events, it becomes important to mitigate and better understand the impact of these emissions. In this paper, engine starts were studied on a hybrid powertrain with experiments.
Injector fouling is an important contributory factor to particulate matter (PM) emissions in Gasoline Direct Injection (GDI) engines. Injector deposits can disrupt fuel spray such that it interacts more with the cylinder liner and piston top, and secondly liquid fuel can be adsorbed on porous carbonaceous deposits on the injector tip that later evaporate at non-ideal points in the engine cycle. Deposit Control Additives (DCAs) are often added to gasoline for the purpose of controlling injector deposits in GDI engines, as well as intake valve deposits (IVDs) in Port Fuel Injected (PFI) Engines. The presence of DCA can often be inferred by an increased level of unwashed gums (UWGs) in the fuel, although it is noted that heavy ends in the fuel, and other constituents of the additive package (especially the carrier fluid) can strongly affect the measured gum levels.