The homogeneous charge compression ignition (HCCI) engine uses a relatively new mode of combustion technology. In principle, there is no spark plug or injector to assist the combustion, and the combustion auto-ignites in multiple spots once the mixture has reached its chemical activation energy. It is noticeably faster than either compression ignition (CI) or spark ignition combustion (SI). The HCCI combustion mode provides better thermal efficiency and maintains low emission by modifying CI as well as SI engines. A wide variety of fuels, combinations of fuels and alternative fuels can be used in this technology. However, some challenges including combustion phase control, limited operating range, cold start, a high level of noise and homogeneous charge preparation need to be overcome for successful operation of HCCI engines. The objective of this study is to illustrate the engine performance and emission characteristics of HCCI engines at different test conditions and various challenges associated with these engines. Also introduced is a potential guideline to overcome these challenges and improve engine performance and emission characteristics. From the review, it can be concluded that HCCI combustion can be applied in existing CI engines with modifications and the most significant result of applying this combustion is the lower NOx and soot emissions with almost the same performance as with CI combustion.

Homogeneous charge compression ignition combustion: Advantages over compression ignition combustion, challenges and solutions

CO2 emissions from a spark ignition engine operating on natural gas–hydrogen blends (HCNG)

Broadband,coherent anti-Stokes Raman scattering (CARS) measurements of unburned gas temperatures have been performed in an internal combustion engine.The engine is fueled with n-butane and air and is operated under both knocking and non-knocking conditons.Temperatures are determined by fitting calculated CARS spectra to experimentally obtained,cycle-averaged nitrogen CARS spectra.The accuracy of the fitted temperature depends on a number of factors,including the modeling of collisional narrowing and the response of the intensified diode array detector,the accuracy of nitrogen linewidths and nonresonant susceptibilities used in the CARS fitting code,and the use of the correct laser line shape convolution.The estimated accuracy of the CARS temperatures is 5-9 percent and is presently limited by long-term drift in the broadband dye laser frequency spectrum.The CARS temperatures are compared with the temperature predictions of a heat release model for the engine.The implications of the measurements f...

Unburned Gas Temperatures in an Internal Combustion Engine. I:Cars Temperature Measurements

The Effects of Physical Factors on Ignition Delay

Temperature and Density Measurements in an Engine by Pulsed Raman Spectroscopy

THIS paper outlines a new method of measuring end-gas temperatures within the cylinder of an operating engine. The new instrument measures the acoustical properties by the pulse method, transmitting an acoustical impulse through a gas path of known length and measuring the time of propagation through the gas. The method yields a value for the average velocity of sound in the path. The authors describe the instrument and engine modifications necessary. The results of tests are also discussed, with a detailed description of one series. The appendixes outline the mathematical steps of finding the sound velocity in gas mixtures and the fuel-air cycle for the detailed series of tests.

C. F. Taylor

Papers

Measurement of -- Gas Temperature in an Engine by the VELOCITY OF SOUND METHOD