Final Report: A High Efficiency, Extremely Low Emission Internal Combustion Engine With On-Demand Generation of Hydrogen-Rich Gas by a PlasmatronEPA Contract Number: 68D00247
Title: A High Efficiency, Extremely Low Emission Internal Combustion Engine With On-Demand Generation of Hydrogen-Rich Gas by a Plasmatron
Investigators: Andrews, Craig C.
Small Business: Lynntech Inc.
Project Period: September 1, 2000 through March 1, 2001
Project Amount: $70,000
RFA: Small Business Innovation Research (SBIR) - Phase I (2000) RFA Text | Recipients Lists
Research Category: SBIR - Pollution Prevention , Pollution Prevention/Sustainable Development , Small Business Innovation Research (SBIR)
Description:The technology of this project is designed to incorporate a suitable plasma operated, fuel-fed, hydrogen generator into a diesel engine. This device results in improved engine efficiency and decreased pollutant emissions for either diesel or gasoline engines. The technology possesses the following features:
Combustion will be complete, eliminating hydrocarbon emissions, while simultaneously eliminating NOx emissions through the preferential scavenging of oxygen by the highly active hydrogen. This prevents oxygen-nitrogen combinations, which typically result in NOx formation.
Lynntech's plasmatron is an integral part of the engine, where all energy exhausted from the converter is fed directly to the engine, to be recovered in the conventional combustion process. Thus, overcoming typical loss of 20% of the primary energy content of the fuel that is characteristic of current existing external plasma reforming technologies.
Summary/Accomplishments (Outputs/Outcomes):Feasibility studies of the above research yielded the following results:
A plasma is easily produced in liquid diesel with a simple spark plug-type plasmatron. The gap size that is required for safe sparking at voltage levels comparable to a conventional automotive ignition system is approximately one forth.
The gas produced in the conversion process contained up to 88% hydrogen by volume. Finely dispersed carbon soot, a highly combustible form of carbon, was produced and remained in suspension in the liquid phase. The longer chained hydrocarbon components (>C10) of the diesel fuel were cracked into shorter chains (<C8).
Early results of the energy requirement of the plasmatron, as it was built with a conventional spark plug powered by an automotive ignition system, exceeded the power delivered by the engine. For these results 14% hydrogen by weight in the combustible gas were assumed a value that is known to reduce pollutants by approximately one order of magnitude.
While theoretical calculations, assuming ideal conditions, showed that the plasmatron needs approximately 10 % of the engine's power to be driven. None of the plasma sources used in this Phase I project showed this efficiency. One reason is because they were not optimized in terms of impedance match to the load (spark plasma), nor were they large enough to produce a large and hot enough plasma to be highly energy efficient. In general, however, Table 2 is encouraging and shows that when the energy input into the plasma increases, so does the conversion efficiency.
Table 1. Energy requirement and performance of various tested sparking power sources.
|System||Power Input (W)||Conversion Gas Production (ml/min)||Required Powerd to Drive Plasmatron (kW)|
|12V driven coil, 20 Hz||23||1.3||750|
|12 V driven coil, 100 Hz||24||5.0||203|
|24V driven coil,250 Hz||86||33.6||115|
|TV flyback transformer||3.2*||1.9||85|
*Measured power delivered to spark plug
It was established that pressures could be produced in liquid diesel. However, the level and the time required to do so were not sufficient to eject diesel from an injection nozzle. The main reason appeared to be too small an energy density in the spark plasma. Even though it was attempted to deliver more power to the spark plug, which resulted in significant improvements, pressures exceeding the cracking pressure of the injection nozzle of 70 atm could not be achieved. One reason for this difficulty was the impedance mismatch between a typically high impedance power source, such as an automotive ignition coil or a TV flyback transformer.
Conclusions:This feasibility study successfully showed that liquid diesel fuel could directly be converted into hydrogen-rich gas. This process is innovative and beneficial, because it does not sacrifice any of the primary energy content to partial oxidation. In this project the feasibility was studied to simultaneously produce high pressures in the diesel fuel delivery system to the nozzle for direct fuel injection. The energies used to produce the plasmas were not high enough to produce sufficient pressures to operate a conventional fuel injector nozzle.
Because hydrogen is produced in-situ no hazardous storage is required to operate systems such as fuel cells. To test the possibility of injecting and converting diesel in the liquid fuel line to the nozzle, further studies are needed. The key point to a successful plasmatron system will be to lower the energy requirements of the plasmatron.