Optimal Degree of Hybridization for Spark-Ignited Engines with Optional Variable Valve Timings

Detecting Knock in Spark Ignited Engines

In this paper we consider signal processing algorithms for detecting knock, i.e. auto-ignition of unburned fuel, in spark-ignited engines. To operate an engine with optimal efficiency, there is a need to operate close to the knock limit. This motivates the need for efficient knock detection algorithms that not only indicates knock, but also gives estimates on knock timing and size. The proposed...

Sensor Selection for Observer Feedback in Turbocharged Spark Ignited Engines

Precise air/fuel control is necessary for low emissions in turbocharged (TC) SI-engines. Observers are often proposed for accurate cylinder air charge estimation in air/fuel controllers. First it is shown using a structural method that the system is locally structurally observable using observer-feedback from any measured state. A systematic method to select observer feedback signals is importa...

Cylinder Pressure and Ionization Current Modeling for Spark Ignited Engines

Engine management systems (EMS) need feedback on combustion performance to optimally control internal combustion engines. Ion sensing is one of the cheapest and most simple methods for monitoring the combustion event in a spark ignited engine, but still the physical processes behind the formation of the ionization current are not fully understood. The goal here is to investigate models for ioni...

Catalytic Converters for Small Spark-Ignited Nonhandheld Utility Engines

Cycle-by-cycle Combustion Variations in Spark-ignited Engines

Under constant nominal operating conditions, internal combustion engines can exhibit substantial variation in combustion efficiency from one cycle to the next. Previous researchers have attempted to explain these variations as resulting from stochastic, linear, or chaotic physical processes. Our investigations indicate that cyclic combustion variations can be explained as the result of interact...