Advanced Combustion Techniques and Engine Technologies for the Automotive Sector

To resolve the transportation sector issues such as rapidly increasing petroleum consumption and stringent emission norms for vehicles, researchers have proposed three solution strategies namely advanced combustion techniques, after-treatment systems and alternative fuels. This book covers all three aspects for automotive sector. A dedicated section of this book is based on methanol, which discusses about the methanol utilization strategies in vehicles, especially in two wheelers. Second section of this book is based on advanced combustion techniques, which includes gasoline compression ignition (GCI), gasoline direct injection (GDI), and spark assisted compression ignition (SACI). Fourth section is based on emissions and after treatments systems. Last section of this book includes two different aspects. First is the vehicle lightweighting and second is the development of UAVs for defence applications. Overall this book emphasizes on different techniques, which can improve engine efficiency and reduce harmful emissions for a sustainable transport system.

With environmental pollution norms becoming increasingly stringent, there is a need for alternate combustion techniques and alternate fuels to keep up with the changing trends. One of the viable solutions for India is the adaptation of methanol as a fuel for automotive sector. Methanol could be produced from stray carbon resources such as high ash coal, municipal solid waste (MSW) and low-value agricultural biomass, and it can be potentially a good substitute for imported petroleum-based fuels. Methanol has a higher Octane number and emits lower hydrocarbon and NOx. Engine noise and vibrations of methanol-fuelled engines are also relatively lesser than equivalent petrol engines. Further, better fuel properties of methanol lead to higher engine efficiency, which in turn lead to higher well-to-wheel efficiency vis-à-vis gasoline. This chapter covers challenges in developing the retrofitment kit for existing electronic fuel injection (EFI) two-wheelers with minimal structural changes for successful M85 adaptation. In a fuel injection system equipped engine, combustion is primarily governed by Electronic Control Unit (ECU) map, which controls the amount of fuel injected in the cylinder and also the spark timings based on various parameters like engine speed, manifold air pressure, throttle position, engine temperature, intake air temperature, acceleration, altitude etc. This chapter primarily deals with the methodology for theoretical and experimental investigations for ECU calibration, which can ensure flawless performance and on-road drivability of M85 fueled motorcycle.

The environmental concern and the financial markets over the global scale, alternative fuels were developed to substitute convention fuel. Methanol is a substitute for conventional fuel which can be used in an Internal Combustion (IC) engine. Methanol is an alternative fuel for IC engines in terms of environment and economical aspect. It is renewable, economically, and environmentally interesting. A sustainable strategy is proposed to use methanol in the internal combustion engine in various ranges of concentration. In this chapter, various research data were studied and cited to understand material compatibility aspects and engineering challenges for engine parts made of metals, elastomers, and plastics. The fuel chemistry and quality effects on the engine are discussed. The effects of methanol on the various components of internal combustion engines are studied. The corrosion and wear of engine components are studied and suggested the suitable material for the engine parts which are coming in contact with methanol. The implementations of methanol in spark ignition engine and compression ignition are studied. The engineering path-way of the implementation and design is explained in detail. The design of different engine components such as engine head, fuel injection system, fuel pump, after treatment for methanol fuelled engines are studied and suggested. The vehicle adaptation for methanol fuel is also studied.

Most developed countries use indigenous fuels for powering their transport sector, however developing countries have to import transport fuels/petroleum to produce transport fuels and they struggle for fuel production from domestic resources. India is focusing on reduction of fuel import by introducing indigenous transport fuels such as variety of biofuels. High ash content coal is available in India, which cannot be used for electricity generation, however this can be used for methanol production using gasification route that can be used to power the Indian transport sector. Although methanol production is already done in India and the current production capacity cannot fulfil the huge demand of the transport sector currently. However methanol economy initiative is gaining momentum due to active intervention of Government of India (GoI) and the technology is being developed for methanol production from high ash coal, municipal solid waste (MSW) and low value agricultural resides. Methanol has great potential to be utilized in spark ignition (SI) engines. This chapter is explores methanol utilization in small carburetor assisted two-wheelers. Two-wheelers population in Indian road transport sector is more than 70% in terms of number of vehicles registered. Carburetor is used to induct the fuel in these small capacity (100–150 cc) SI engines. Existing engines are designed to operate on gasoline therefore slight modifications become essential for adaptation of methanol in these existing two-wheelers. Currently, India is preparing a road map for large scale adaptation of M15 (15% v/v methanol and 85% v/v gasoline) in the existing SI engines, which has several challenges. This chapter summarises challenges and possible solutions for adaptation of M15 in carburetor assisted two-wheelers.

Compression ignition (CI) engines are mainly fuelled by diesel-like high cetane fuels, and they have higher overall efficiency due to higher compression ratio compared to their spark ignition (SI) engine counterparts. However, modern diesel engines are more expensive, complicated, and emit high nitrogen oxides (NOx) and particulate matter (PM). Simultaneous control of soot and NOx emissions in diesel engines is quite challenging and expensive. Thermal efficiency of SI engines, on the other hand is limited by the tendency of abnormal combustion at higher compression ratios therefore use of high octane fuel is essential for developing more efficient higher compression ratio SI engines in near future. In the foreseeable future, refineries will process heavier crude oil to produce relatively inferior petroleum products to power the IC engines. Also, fuel demand will shift more towards diesel and jet fuels, which would lead to availability of surplus amounts of low octane gasoline with oil marketing companies, with little apparent use for operating the engines. This low octane gasoline will be cheaper and would be available in excess quantities in foreseeable future as the demand for gasoline will further drop due to increase in the fuel economy of modern generation gasoline fuelled vehicles. For addressing these issues, Gasoline compression ignition (GCI) engine technology is being developed, which is a futuristic engine technology that takes advantage of higher volatility, and higher auto-ignition temperature of gasoline and higher compression ratio (CR) of a diesel engine simultaneously to take care of soot and NOx emissions without compromising diesel engine like efficiency. GCI engines can efficiently operate on low octane gasoline (RON of ~70) with better controls at part load conditions. However cold starting, high CO and HC emissions, combustion stability at part load, and high combustion noise at medium-to-full load operations are some of the challenges associated with GCI engine technology. Introductory sections of this chapter highlights future energy and transport scenario, trends of future fuel demand, availability of low octane fuels and development in advanced engine combustion technologies such as HCCI, PCCI, RCCI, and GDI. GCI engine development, its combustion characteristics and controls are discussed in detail. Particular emphasis is given to the effect of various control strategies on GCI combustion, performance and emissions, fuel quality requirement and adaption of GCI technology in modern CI engines. In addition, this chapter reviews initial experimental studies to assess the potential benefits of GCI technology.

Gasoline direct injection engines have become the popular powertrain for commercial cars in the market. The technology is known for its characteristics of high power output, thermal efficiency and fuel economy. Accurate metering of fuel injection with better fuel utilization makes the engine possible to run on lean mixtures and operation under higher compression ratio relatively makes it of greater potential than PFI engines. Due to its capability of being operated under dual combustion mode by varying fuel injection timing, it can be realized as a cornerstone for future engine technology. Under mode switching, the homogeneous mixture for higher power output at medium and high load-rpm conditions, and stratified mixture for greater fuel economy at low load-rpm conditions are achieved respectively. It can be considered as the technology having the benefits of both diesel engine of higher thermal efficiency and gasoline engine of higher specific power output. But, with the growing concerns towards the limited fuel reserves and the deteriorated environment conditions, strict norms for tail-pipe emissions have been regulated. And considering the higher particulate matter and particle number emissions as a major drawback for GDI engine, upgradation and improvement in designs is needed to meet the required norms of emissions. In the initial section, the chapter gives a brief idea of the overview of the GDI combustion system and its operating modes. Subsequently, the improvements and researches in various aspects like fuel injection parameters and strategies, dual fuel utilization, mixture formation, lean burn control and application of providing turbocharging and residual gas fraction, are elaborately discussed in the direction of optimizing the performance of the engine. Further, the following section explains the major challenges and overcoming of this technology. Review of the work done by various researchers is discussed, focussing on the effect of operating parameters on particulates emissions, injector deposits and knocking in GDI engine. Finally, the chapter presents the concluding ways for enhancing the performance, way forward for making it more efficient and reliable by overcoming the limitations of GDI engine technologies.

With strict environmental legislations and to reduce related health hazards, there is immense focus on reducing particulates from gasoline direct injection engines. With increasing use of biofuels in the market, their blends with hydrocarbon fuels are also being considered as cleaner alternatives to gasoline. This chapter confers the addition of oxygenates to gasoline and their capacity to reduce sooting tendency compared to gasoline. Challenges related to optimizing combustion by appropriately choosing engine parameters such as start of ignition, duration of injection, etc. have been addressed. Optimizing combustion can reduce the particulate emissions, by sometimes increasing efficiency. Oxygenated fuels always have the advantage of higher oxidation of soot formed inside the cylinder, which further reduces particulate emissions. Towards the end of this chapter, disadvantages of using oxygenated fuel blends or alternate fuels are discussed.

The mixed-mode engine combustion strategy where some combination of spark-assisted compression ignition (SACI) and pure advanced compression ignition (ACI) are used at part-load operation with exclusive spark-ignited (SI) combustion used for high power-density conditions has the potential to increase efficiency and decrease pollutant emissions. However, controlling combustion and switching between different modes of mixed-mode operation is inherently challenging. This chapter proposes to use ozone (O₃)—a powerful oxidizing chemical agent—to maintain stable and knock-free combustion across the load-speed map. The impact of 0–50 ppm intake seeded O₃ on performance, and emissions characteristics was explored in a single-cylinder, optically accessible, research engine operated under lean SACI conditions with two different in-cylinder conditions, (1) partially stratified (double injection—early and late injection) and (2) homogeneous (single early injection). O₃ addition promotes end gas auto-ignition by enhancing the gasoline reactivity, which thereby enabled stable auto-ignition with less initial charge heating. Hence O₃ addition could stabilize engine combustion relative to similar conditions without O₃. The addition of ozone has been found to reduce specific fuel consumption by up to 9%, with an overall improvement in the combustion stability compared to similar conditions without O₃. For the lowest loads, the effect of adding O₃ was most substantial. Specific NO_x emissions also dropped by up to 30% because a higher fraction of the fuel burned was due to auto-ignition of the end gas. Measurement of in-cylinder O₃ concentrations using UV light absorption technique showed that rapid decomposition of O₃ into molecular (O₂) and atomic oxygen (O) concurred with the onset of low-temperature heat release (LTHR). The newly formed O from O₃ decomposition initiated fuel hydrogen abstraction reactions responsible for early onset of LTHR. At the beginning of high-temperature heat release (HTHR), end gas temperatures ranged from 840 to 900 K, which is about 200 K cooler than those found in previous studies where intake charge heating or extensive retained residuals were used to preheat the charge. An included analysis indicates that in order to achieve optimal auto-ignition in our engine, the spark deflagration was needed to add 10–40 J of additional thermal energy to the end gas. We have leveraged these results to broaden our understanding of O₃ addition to different load-speed conditions that we believe can facilitate multiple modes (SI, ACI, SACI, etc.) of combustion.

The present study elucidates on PM_2.5 (particle aerodynamic diameter ≤ 2.5 μm) bound trace metals characterization from on-road light-duty vehicles during on-road operation and their health risk assessment for adults and children. The vehicles assessed in present work included 4-wheelers passenger cars with a different age group of Bharat Stage (BS) II, III, and IV and different fuel type [diesel, gasoline and compressed natural gas (CNG)]. To understand the particle losses, particle formation, and homogenous mixing, firstly, a new portable dilution system (PDS) was designed for diluting the exhaust with adequate aerosol formation and growth, and evaluated beforehand under controlled condition in laboratory for diesel vehicles over a wide range of dilution ratio (30:1, 60:1, and 90:1). For on-road experiments, a PDS, a heated duct, a gas analyzer, an exhaust velocity probe, a temperature, and relative humidity probe were mounted on Aerosol Emissions Measurement System (AEMS) and it was towed behind the vehicle. Total 46 experiments were performed on a mixed traffic route in Delhi city, and PM_2.5 mass was collected on Teflon and quartz filter using multi-stream PM_2.5 sampler. Total 17 trace metals (Al, Ag, As, Ba, Co, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Se, Sr, Ti, V, and Zn) were characterized on Teflon filters using Induced Coupled Plasma-Mass Spectrometry (ICP-MS). Out of these metals, the non-carcinogenic and carcinogenic risks for adults and children were calculated for 5 metals namely Cr, Mn, Ni, Zn, and Pb. Trace metals concentration was highest in exhaust emitted from 4W-diesel followed by 4W-gasoline, 3W-CNG, and 2W-gasoline. Trace metals such as Cr, Mn, Ni, Zn, and Pb were present in high amount (25.2 ± 8.6 μg m⁻³). The carcinogenic risk from Cr was considerably higher than tolerable risk (10⁻⁴), while the risk from other metals such as Ni, As, Cd, and Pb was within the range of safe (10⁻⁶) and tolerable (10⁻⁴) level. Overall, the human health risks associated with the exposure to PM_2.5 emitted from gasoline and CNG vehicles were higher than that from diesel vehicle. This estimated risk in this work can help in refining the burden of disease and crafting policy to help reduce the exposures. This study is limited only for PM_2.5 bound trace metals and associated health risk from on-road vehicle emissions. However, poly-aromatic hydrocarbons (PAHs), perfluorinated compounds (PFCs), and semi-volatile compounds in vehicular exhaust can also impose a severe risk to human health which needs to be assessed to evaluate combined risk.

Majority of passenger vehicles run on diesel and sold in India, new millennium have become the preferred choice of the customers along with commercial vehicles due to lower fuel cost, more mileage and comparable performance as compared to petrol driven vehicle apart from having better thermal efficiency due to its high compression ratio. However, the diesel-powered vehicle produces relatively high particulate emissions along with other pollutants when compared to petrol vehicles. Bharat Stage (BS) VI requires a 90% reduction of Diesel Particulate Matter (DPM) from BS IV. This high level of reduction in the DPM can be achieved with the help of diesel particulate filter (DPF). Incorporating DPF in the tail-pipe of a diesel engine is challenging as it requires its appropriate size, accurate position in the tailpipe and minimum pressure drop. Adding a DPF not only reduces the amount of DPM released into the atmosphere, but also help to reduce the fuel consumption, better transient response, and minimize operating costs. This chapter discusses the comprehensive details of material and regeneration processes used in DPF, including action plan for developing it BS-VI compatible.

Unmanned Aerial Vehicles (UAVs) have been extensively used for a wide range of applications since World War-II. UAVs are used for several defence purposes such as surveillance, communication, terrain mapping, reconnaissance, and attack. In this chapter, we discuss reciprocating internal combustion engine as a propulsion system for UAVs and the challenges in development of such an engine for aviation. The reciprocating piston engine is one of the most effective powerplants to energise the UAVs. The purpose of these propulsion systems in UAVs is to provide durable, reliable, and extended flight. Currently, no such engine for UAV applications are manufactured in India, and defence sector relies on imported engines only, which severely restricts their application for various other defence applications. This chapter addresses technical issues present in these systems, thus contributing to their development. Aspects related to structural and thermal analysis of engine components have also been discussed, which are essential for designing such engines. This chapter gives broad idea about future of UAV propulsion systems and associated challenges.

Automotive emissions account for a substantial percentage of the planet’s Greenhouse Gas (GHG) emissions and the numbers have been steadily soaring. Environmental bodies and governments are therefore constantly enforcing tighter legislations and as a result automotive OEMs are forced to ensure decreased emissions. While safety requirements and luxurious interiors have resulted in a gain of weight over the decades thus increasing emissions, OEMs are persistently being asked to cut down emissions from fossil fuel driven vehicles, especially given the rise of electric vehicles in recent years. OEMs have thus started replacing parts originally made with heavier materials with lighter materials in order to reduce the overall weight of the vehicle—also known as lightweighting. While the original cast iron engine blocks have long been replaced with steels followed by Aluminium, Magnesium alloys and the more recent carbon fibre for certain engine parts; studies have also started exploring the benefits of advanced composites such as cellulose based composites.