Harold Schock
Professor of Mechanical Engineering | Michigan State University
East Lansing, MI, UNITED STATES
An expert in automotive fuel efficiency and alternative energy and flow and combustion phenomena in internal combustion engines.
Media
Publications:
Documents:
Videos:
Audio/Podcasts:
Biography
Dr. Harold Schock received his BS in Mechanical Engineering from Michigan Technological University in 1974 and his MS in Mechanical Engineering from the University of Michigan-Ann Arbor in 1975. He then returned to Michigan Tech and earned his PhD in Engineering Mechanics in 1979. While earning his PhD at Tech, Dr. Schock worked as a research assistant and a teaching assistant.
Industry Expertise (2)
Writing and Editing
Education/Learning
Areas of Expertise (5)
Internal combustion engines
Optical diagnostics
Thermodynamics
Combustion
Turbulence
Education (3)
Michigan Technological University: Ph.D.
University of Michigan: M.S.
Michigan Technological University: B.S.
Links (1)
Journal Articles (3)
Visualization of Propane and Natural Gas Spark Ignition and Turbulent Jet Ignition Combustion
SAE International Journal of EnginesElisa Toulson, Andrew Huisjen, Xuefei Chen, Cody Squibb, Guoming Zhu, Harold Schock and William P. Attard
2012 This study focuses on the combustion visualization of spark ignition combustion in an optical single cylinder engine using natural gas and propane at several air to fuel ratios and speed-load operating points. Propane and natural gas fuels were compared as they are the most promising gaseous alternative fuels for reciprocating powertrains, with both fuels beginning to find wide market penetration on the fleet level across many regions of the world. Additionally, when compared to gasoline, these gaseous fuels are affordable, have high knock resistance and relatively low carbon content and they do not suffer from the complex re-fueling and storage problems associated with hydrogen. Although both propane and natural gas offer unique lean burn benefits for spark ignition combustion, a novel Turbulent Jet Ignition pre-chamber system was also evaluated, with several Turbulent Jet Ignition optical images compared to the spark ignition images in order to provide insight into the lean limit extension provided by the pre-chamber combustion system. Turbulent Jet Ignition enables very fast burn rates due to the ignition system producing multiple, widely distributed ignition sites, which consume the main charge rapidly. This high energy ignition results from the partially combusted (reacting) pre-chamber products initiating combustion in the main chamber. The distributed ignition sites enable relatively small flame travel distances enabling short combustion durations and ultra lean engine operation exceeding lambda 2. Experimental findings from the spark ignition study highlight faster flame propagation with propane when compared to natural gas across all speed load points tested. However, across all fuels, the optical images revealed rapid spark ignition combustion deterioration with lean engine operation exceeding lambda 1.4. When comparing ignition systems, the Turbulent Jet Ignition pre-chamber system demonstrated significant benefits relative to the spark ignition system, with the optical images revealing stable combustion past lambda 1.8 resulting in the near elimination of NOx emissions in-cylinder and significant improvements in efficiency and fuel economy.
A Review of Pre-Chamber Initiated Jet Ignition Combustion Systems
SAE TechnicalToulson, E., Schock, H., and Attard, W.
2010 This paper reviews progress on turbulent jet ignition systems for otherwise standard spark ignition engines, with focus on small prechamber systems (≺3% of clearance volume) with auxiliary pre-chamber fueling. The review covers a range of systems including early designs such as those by Gussak and Oppenheim and more recent designs proposed by General Motors Corporation, FEV, Bosch and MAHLE Powertrain. A major advantage of jet ignition systems is that they enable very fast burn rates due to the ignition system producing multiple, distributed ignition sites, which consume the main charge rapidly and with minimal combustion variability. The locally distributed ignition sites allow for increased levels of dilution (lean burn/EGR) when compared to conventional spark ignition combustion. Dilution levels are comparable to those reported in recent homogeneous charge compression ignition (HCCI) systems. In addition, jet ignition systems have the potential for combustion phasing control and hence speed/load range benefits when compared to HCCI, without the need for SI-HCCI combustion mode switching. The faster burn rates also allow for a base compression ratio increase (1-2 points) when compared to spark ignition and when combined with diluted mixture combustion, provide increased engine efficiency.
Nanostructured Thermoelectric Materials and High-Efficiency Power-Generation Modules
Journal of Electronic MaterialsHarold Schock et al.
2007 For thermoelectric applications, the best materials have high electrical conductivity and thermopower and, simultaneously, low thermal conductivity. Such a combination of properties is usually found in heavily doped semiconductors. Renewed interest in this topic has followed recent theoretical predictions that significant increases in performance are possible for nanostructured materials, and this has been experimentally verified. During exploratory synthetic studies of chalcogenide-based bulk thermoelectric materials it was discovered that several compounds spontaneously formed endotaxially embedded nanostructures. These compounds have some of the best known properties for bulk thermoelectric materials in the 500–800 K temperature range. Here we report our continued efforts to better understand the role of the nanostructures while concurrently furthering the development of these new materials (for example n-type lead–antimony–silver–tellurium, and p-type lead–antimony–silver–tin–tellurium) into thermoelectric power-generation devices.
