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In-cylinder reactions of several internal combustion engine configurations were investigated using a highspeed four-spectral infrared (IR) digital imaging device. The study was conducted with a greater emphasis on the preflame processes by mutually comparing results from different engine-fuel systems. The main features of the methods employed in the study include that the present multi-spectral IR imaging system permits us to capture progressively changing radiation emitted by new species produced in-cylinder fuel-air mixtures prior to being consumed by the heat-releasing reaction fronts. The study of the Diesel or compression-ignition (CI) engine reactions was performed by varying several parameters, e.g. injection pressures, intake air temperature, fuel air ratio, and the start of injection.

In-cylinder reaction processes in a production port-fuel-injection (PFI) spark-ignition engine having optical access were visualized using a high speed four-spectra IR Imaging system. Over one thousand sets of digital movies were accumulated for this study. To conduct a close analysis of this vast amount of results, a new data analysis and presentation method was developed, which permits the simultaneous display of as many as twenty-eight (28) digital movies over a single PC screen in a controlled manner, which is called the Rutgers Animation Program (RAP for short). The results of this parametric study of the in-cylinder processes (including the period before and after the presence of luminous flame fronts) suggest that, even after the engine was well warmed, liquid fuel layers (LFL) are formed over and in the vicinity of the intake valve to which the PFI was mated.

Visualization of in-cylinder reaction processes and performance analysis of a direct-injection Diesel engine equipped with a high injection pressure (HIP) unit were conducted. The study was directed towards evaluation of high-power-density (HPD) engine design strategies, which utilize more intake air operating at rich overall fuel-air ratios. Two separate engine apparatus were used in this study: a Cummins 903 engine and a single-cylinder optical engine equipped with the same family engine components including the cylinder head. The engines were mated with an intensifier-type HIP fuel system fabricated at Rutgers which can deliver fuel injection pressure of over 200 MPa (30,000psi). The one-of-a-kind high-speed four-band infrared (IR) imaging system was used to obtain over fifteen hundred sets of spectral digital movies under varied engine design and operating conditions for the present analysis.

A single-cylinder direct-injection (DI) Diesel engine (Cummins 903) equipped with a new laboratory-built electronically controlled high injection pressure fuel unit (HIP) was studied in order to evaluate design strategies for achieving a high power density (HPD) compression ignition (CI) engine. In performing the present parametric study of engine response to design changes, the HIP was designed to deliver injection pressures variable to over 210 MPa (30,625psi). Among other parameters investigated for the analysis of the I-IPD DI-CI engine with an HIP were the air/fuel ratio ranging from 18 to 36, and intake air temperature as high as 205°C (400°F). The high temperatures in the latter were considered in order to evaluate combustion reactions expected in an uncooled (or low-heat-rejection) engine for a HPD, which operates without cooling the cylinder. Engine measurements from the study include: indicated mean effective pressure, fuel consumption, and smoke emissions.

The crank angle locations for the first occurrences of several main combustion events in a Diesel engine were investigated for varied fuel parameters. The events studied include preflame reactions premixed flame propagation, start of pressure rise, maximum rate of pressure rise (dp/dt), and peak cylinder pressure. The fuels employed in the study were in two groups (1) Base fuel-1 and derivatives prepared by mixing it with small doses of a cetane number (CN) enhancing additive and (2) Base fuel-2 and those made by adding different amounts of bio-Diesel fuel. The experiment was performed by using a single-cylinder direct-injection (DI) Diesel engine equipped with an electronically controlled high-pressure fuel injection unit. The in-cylinder processes during the periods of ignition delay and combustion reaction were measured by using a high-speed multispectral infrared (IR) imaging system developed at Rutgers University. The other events were found from the pressure-time history.

The flame propagations in the very first firing and subsequent cycles in an SI engine during cold start were studied to gain a better understanding of reaction fronts associated with liquid fuel (regular unleaded) in the cylinder. This work was performed using the Rutgers high-speed spectral infrared digital imaging system on a single-cylinder engine with optical access. The engine was mounted with a production engine cylinder-head mated with a conventional port fuel injection (PFI) system. In the study, four images in respective spectral bands were simultaneously obtained at successive instants of time during the combustion period, which was done for eight sequential cycles. This multiple-band successive-imaging was repeated in intervals of about two minutes over a period of more than twenty-five minutes after the engine start. During this experiment, the temperature changes at the intake port, the water jacket and the exhaust gas were monitored.

Many recent publications indicate that spark ignition (SI) engines equipped with the conventional port-injection fuel system (PIF) seem to have serious fuel-maldistribution problems, including the formation of liquid layers over the combustion chamber surfaces. It is reasonable to expect that such a maldistribution is an unfavorable condition for the flame propagation in the cylinder. The in-cylinder flame behaviors of a PIF-SI engine as fueled with gasoline are investigated by using the Rutgers high-speed spectral infrared imaging system. These results are then compared with those obtained from the same engine operated by gaseous fuels and other simple fuels. The results from the engine operated by gasoline reveal slowly burning fuel-rich local pockets under both fully warmed and room-temperature conditions. The local pockets seem to stem from the liquid layers formed over the surfaces during the intake period.

In-cylinder process of a direct injection (DI) compression ignition (CI) engine was studied by using the Rutgers high-speed spectral infrared (M) imaging system and the KIVA-II computer code. Comparison of the engine measurements with the computational prediction was attempted. In order to perform the instantaneous IR imaging, a Cummins 903 engine cylinder head was modified by installing an optical access in place of one of the intake valves, which required designing a new rocker-arm mechanism. The measurements obtained using the highspeed dual spectra IR imaging system were processed by the conventional two-color method which employed soot as the radiating target. The KIVA-II program was coded in order to match engine and operation conditions to those employed in the present measurements for achieving mutual consistency of the analysis.