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Bringing the Fire
Published in Patrick Hossay, Automotive Innovation, 2019
The use of high-pressure direct injection does not exclude the use of lower pressure port injection; in fact, the two can be used to compliment each other. So, while direct injection offers a cooler combustion chamber and so helps avoid knocking, a port injection system can cool the incoming air and thus allow for its increased density and a resulting improved air intake efficiency (see the next chapter for volumetric efficiency). This allows the best of both worlds. The cooling effect of GDI on the combustion chamber can reduce knocking and potentially allow for a higher compression ratio for greater efficiency. And by allowing more time for the fuel to vaporize, port injection can reduce some of the challenges of exclusive direct injection. Direct injection can deliver fuel at high engine loads, when chamber cooling is important, and a combination can be used at lower loads to help keep injectors clear and efficiency high.
Diesel (compression ignition) engines
Published in Allan Bonnick, Automotive Powertrain Science and Technology, 2020
Basically two methods of injection are used in automotive CI engines: Direct injection, in which the fuel is injected directly into the combustion chamber.Indirect injection, in which the fuel is injected into a pre-combustion chamber where it is mixed with air, so that combustion takes place as the burning gas enters the main combustion space. This is said to reduce the delay period with a resulting drop in diesel knock.
Trends in Transportation
Published in Michael Frank Hordeski, Hydrogen & Fuel Cells: Advances in Transportation and Power, 2020
Daimler-Benz has accumulated data on NECAR III emissions with a dynamometer programmed for a mix of urban and suburban driving. The results were promising since there were zero emissions for nitrogen oxide and carbon monoxide, and extremely low hydrocarbon emissions of only .0005 per gram per mile. NECAR III did produce significant quantities of carbon dioxide similar to the emissions of a direct-injection diesel engine where the fuel is injected directly into the combustion chamber. Direct-injection produces less combustion residue and unburned fuel.
Methanol as a fuel additive: effect on the performance and emissions of a gasoline engine
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2023
Mehrez Gassoumi, Zouhair Boutar, Raja Mazuir Raja Ahsan Shah, Mohannad T. Aljarrah, Mansour Al Qubeissi, Ridha Ennetta, Angelo Onorati, Hakan Serhad Soyhan
Methanol has become a promising fuel additive due to its ability to reduce emissions and increase octane levels. New research trends and technological applications have focused on optimizing the use of methanol as a gasoline additive, either in premixed form or using dual fuel systems (Bansal and Meena 2021; Behçet and Yakın 2022). One such application is the use of high-pressure direct injection systems that allow for better control of the combustion process and improve fuel efficiency (Klein 2020). Methanol blending ratio is a crucial parameter for developing any solution. Low-level blends can be adopted, typically, without any modifications or adjustments (Jangid et al. 2019). However higher-level blends create new challenges, particularly due to the high toxicity and corrosivity of methanol requiring more consideration regarding material compatibility and safety handling (IEA-AMF 2020).
An alternative and hybrid propulsion for merchant ships: current state and perspective
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2021
Maro Jelić, Vedran Mrzljak, Gojmir Radica, Nikola Račić
Hydrogen fuel can also be used directly in IC engines, but storage problems with low-energy density and safety problems are the main obstacle to adopt hydrogen as a widely used marine fuel (Seediek, Elgohary, and Ammar 2015). Hydrogen can be stored in compressed tanks (pressure between 350 and 700 bars) or in a liquefied state (cooled to cryogenic temperature of −253°C), and a direct injection of hydrogen into IC engine is considered to be the most acceptable option (Ahn et al. 2017). The advantage of direct injection is based on high volumetric efficiency and good potential for pre-ignition avoiding. The existing diesel engines can be used for direct injection of hydrogen, but small modifications will be required in the form of low-energy sparks to avoid using diesel as a pilot fuel. Fuel pumps and sparks will be electronically controlled (camless engines) to ensure the optimum performance at various operating conditions, Figure 12.
Hot surface ignition and combustion characteristics of sprays in constant volumecombustion chamber using various sensors
Published in Cogent Engineering, 2018
Spray combustion phenomenon occurs in various power systems such as compression-ignition engines, gas turbine engines, furnaces, industrial burners etc. Spray combustion of fuels involves many phenomena such as diffusion, evaporation, convective mixing, jet and droplet breakup and heat transfer, which influence the ignition process. Spray combustion process affects the engine performance such as efficiency, power output, emissions and noise. Nowadays, spray combustion technology is common to automotive engines i.e. gasoline engines as well as diesel engines. Direct injection technology is commonly employed in modern high speed automotive engines. However, in diesel engines, injection of fuel controls the autoignition process unlike that of gasoline engine. Therefore in diesel engines, spray auto-ignition and combustion characteristics are of crucial importance for engine performance and inturn these characteristics depend on fuel injection system characteristics or parameters.