The US Department of Energy (DOE) has awarded a $400,000 contract to TIAX, a leading collaborative product and technology development firm, to develop sensor technology to help control the start of combustion (SOC) in low-temperature combustion (LTC) engines.
DOE has set a goal for 2012 of developing the understanding of novel low-temperature engine combustion regimes needed to increase light-duty engine efficiency from today’s 30% to 45%. Heavy-duty engines have an efficiency target of 55%.
LTC engines, of which Homogeneous Charge Compression Ignition (HCCI) engines are an example, promise diesel-like efficiency (high compression ratios and no throttling) combined with low engine-out NOx and low particulate emissions. (Honda’s promised Tier 2 Bin 5 diesel uses PCCI, a variant of LTC. Earlier post.)
Such combustion regimes are complex to manage, however, and face a number of barriers, including control of combustion and heat-release rates for steady and transient conditions. A number of initiatives are exploring the use of a variety of mechanisms, including mixture formulations, injection strategies (early, late, close-coupled pilot and post, multiple main), valve timings, and spray geometries as mechanisms to optimize combustion under a variety of load ranges. Knowing when combustion initiates under varying conditions could be an important element for adaptive combustion control.
As the prime contractor, TIAX will team with Wayne State University, a leader in engine diagnostics and control, on advancing sensor technology to address this issue. In earlier work for the DOE, TIAX developed a non-intrusive microphone sensor mounted on the engine block that is designed to determine the start of combustion on a cycle-by-cycle basis in the same way that a stethoscope senses heart beats.
The creation of a durable and effective start-of-combustion sensor could solve one of the most critical challenges to the viability of high-efficiency automotive engine platforms. We believe that the sensor technology that we are developing will enable a new breed of engines that can save 10 to 15 percent of the US petroleum now used in transportation, while meeting or exceeding 2010 emissions targets.—Kenan Sahin, CEO and Founder of TIAX