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A 1.9 liter Volkswagen TDI engine has been modified to accomodate the addition of hydrogen into the intake manifold via timed port fuel injection. Engine out particulate matter and the emissions of oxides of nitrogen were investigated. Two fuels,low sulfur diesel fuel (BP50) and soy methyl ester (SME) biodiesel (B99), were tested with supplemental hydrogen fueling. Three test conditions were selected to represent a range of engine operating modes. The tests were executed at 20, 40, and 60 % rated load with a constant engine speed o 1700 RPM. At each test condition the percentage of power from hydrogen energy was varied from 0 to 40 %. This corresponds to hydrogen flow rates ranging from 7 to 85 liters per minute. Particulate matter (PM) emissions were measured using a scaning mobility particle sizer (SMPS) and a two stage micro dilution system. Oxides of nitrogen were also monitored.

Ethanol, used widely as a spark-ignition (SI) engine fuel, has seen minimal success as a compression ignition (CI) engine fuel. The lack of success of ethanol in CI engines is mainly due to ethanol's very low cetane number and its poor lubricity properties. Past researchers have utilized nearly pure ethanol in a CI engine by either increasing the compression ratio which requires extensive engine modification and/or using an expensive ignition improver. The objective of this work was to demonstrate the ability of a hydrogen port fuel injection (PFI) system to facilitate the combustion of ethanol in a CI engine. Non-denatured anhydrous ethanol, mixed with a lubricity additive, was used in a variable compression ratio CI engine. Testing was conducted by varying the amount of bottled hydrogen gas injected into the intake manifold via a PFI system. The hydrogen flowrates were varied from 0 - 10 slpm.

Diesel exhaust particle number concentrations and size distributions, as well as gaseous and particulate mass emissions, were measured during steady-state tests on a US heavy-duty engine and a European passenger car engine. Two fuels were compared, namely a Fischer-Tropsch diesel fuel manufactured from natural gas, and a US D2 on-highway diesel fuel. With both engines, the Fischer-Tropsch fuel showed a considerable reduction in the number of particles formed by nucleation, when compared with the D2 fuel. At most test modes, particle number emissions were dominated by nucleation mode particles. Consequently, there were generally large reductions (up to 93%) in the total particle number emissions with the Fischer-Tropsch fuel. It is thought that the most probable cause for the reduction in nucleation mode particles is the negligible sulphur content of the Fischer-Tropsch fuel. In general, there were also reductions in all the regulated emissions with the Fischer-Tropsch fuel.

This paper describes the performance and emissions of a hydrogen-fueled, spark-ignited engine. An electronic control device, designed to provide the engine with a timed injection of the fuel, is shown to give high mean effective pressures and high efficiencies. The oxides of nitrogen from the exhaust gases have been analyzed and the mechanism for their formation is reviewed. The paper further describes an experiment with traces of hydrocarbons added to the hydrogen in an attempt to explain any additional phenomena that may be taking place during the combustion, such as “prompt NO” which is known to occur in hydrocarbon flames only. As it turns out, such additions have a negligible effect on the NOx formation in the region investigated.

An adaptive control system which determines the optimum system parameters based on the engine response to changes in those parameters, has been tested as an ignition timing control system on several gaseous fueled engines. The changes in the MBT timing for speed, load, air-fuel ratio, and fuel type were explored. The ability of the control system to correct the timing for these parameters was demonstrated. An air-fuel ratio control based on the same technique is also discussed.