Hydrogen-fueled internal combustion engines

Abstract

a b s t r a c tThe threat posed by climate change and the striving for security of energy supply are issues high on the political agenda these days. Governments are putting strategic plans in motion to decrease primary energy use, take carbon out of fuels and facilitate modal shifts.Taking a prominent place in these strategic plans is hydrogen as a future energy carrier. A number of manufacturers are now leasing demonstration vehicles to consumers using hydrogen-fueled internal combustion engines (H 2 ICEs) as well as fuel cell vehicles. Developing countries in particular are pushing for H 2 ICEs (powering two-and three-wheelers as well as passenger cars and buses) to decrease local pollution at an affordable cost.This article offers a comprehensive overview of H 2 ICEs. Topics that are discussed include fundamentals of the combustion of hydrogen, details on the different mixture formation strategies and their emissions characteristics, measures to convert existing vehicles, dedicated hydrogen engine features, a state of the art on increasing power output and efficiency while controlling emissions and modeling.

Biofuels and the Hybrid Fuel Sector

“…Hydrogen is an energy carrier and not an energy resource because free hydrogen is not available in nature and one or the other form of primary energy is required to be invested for its production (MacLean 778 Avinash Kumar Agarwal and Atul Dhar and Lave, 2003;Verhelst and Wallner, 2009). Its usefulness as an excellent energy carrier is also limited because of its low energy content on a volume basis, limiting the possibility of its on board storage in vehicles (MacLean and Lave, 2003).…”

“…Addition of hybrid electric vehicle (HEV) technology improves the fuel economy of both these powertrains. Currently, efficiency and cost of H 2 FC powertrain is higher than H 2 ICE power-train (Verhelst and Wallner, 2009). Generally, hydrogen can be produced by electrolysis or thermal decomposition of water, steam reforming of natural gas and other hydrocarbons, pyrolysis of hydrocarbons, plasma refining process, etc.…”

Impact of variable valve timing on power, emissions and backfire of a bi-fuel hydrogen/gasoline engine

“…Another advantage can be found in the fact that a hydrogen fueled ICE can easily be used as a bi-or flex-fuel engine and can thus be used to avoid the well known "chicken or the egg" dilemma. These benefits and experimental research on hydrogen-fueled ICEs have previously been reviewed by some of the authors [3,4,5].…”

“…The three major bottlenecks are abnormal combustion, performance and NO X output. Although measures can be taken to avoid abnormal combustion (surface ignition, backfire, knock, [3,4,6]), there is no given set of measures with guaranteed success. Backfire (the ignition of the hydrogen-air mixture during the intake process) can be particularly difficult to predict and is thus the most difficult to control [7].…”

“…Starting from a gasoline engine implies port fuel injection (PFI) of the hydrogen. Therefore, this paper concentrates on hydrogen PFI engines, although dedicated hydrogen engines would benefit greatly from direct injection [3,4,11,12] and novel concepts for mixture formation have been reported [13]. Also, work has been published on compression ignition operation on H 2 [14].…”