Effects of Variable Inlet Valve Timing and Swirl Ratio on Combustion and Emissions in a Heavy Duty Diesel Engine

2012 ◽  
Author(s):  
Malin Ehleskog ◽  
Savo Gjirja ◽  
Ingemar Denbratt
Keyword(s):  
Diesel Engine ◽  
Swirl Ratio ◽  
Valve Timing ◽  
Heavy Duty ◽  
Inlet Valve ◽  
Heavy Duty Diesel Engine ◽  
Heavy Duty Diesel

A Computational Investigation of Piston Bowl Geometry and Injector Spray Pattern Effects on Gasoline Compression Ignition in a Heavy-Duty Diesel Engine

2019 ◽  
Author(s):  
Yu Zhang ◽  
Yuanjiang Pei ◽  
Meng Tang ◽  
Michael Traver
Keyword(s):  
Diesel Engine ◽  
Fuel Efficiency ◽  
Compression Ignition ◽  
Swirl Ratio ◽  
Heavy Duty ◽  
Load Range ◽  
Spray Pattern ◽  
Piston Bowl ◽  
Heavy Duty Diesel Engine ◽  
Heavy Duty Diesel

Abstract This study computationally investigates the potential of utilizing gasoline compression ignition (GCI) in a heavy-duty diesel engine to address a future ultra-low tailpipe NOx standard of 0.027 g/kWh while achieving high fuel efficiency. By conducting closed-cycle, full-geometry, 3-D computational fluid dynamics (CFD) combustion simulations, the effects of piston bowl geometry, injector spray pattern, and swirl ratio (SR) were investigated for a market gasoline. The simulations were performed at 1375 rpm over a load range from 5 to 15 bar BMEP. The engine compression ratio (CR) was increased from 15.7 used in previous work to 16.5 for this study. Two piston bowl concepts were studied with Design 1 attained by simply scaling from the baseline 15.7 CR piston bowl, and Design 2 exploring a wider and shallower combustion chamber design. The simulation results predicted that through a combination of the wider and shallower piston bowl design, a 14-hole injector spray pattern, and a swirl ratio of 1, Design 2 would lead to a 2–7% indicated specific fuel consumption (ISFC) improvement over the baseline by reducing the spray-wall interactions and lowering the in-cylinder heat transfer loss. Design 1 (10-hole and SR2) showed a more moderate ISFC reduction of 1–4% by increasing CR and the number of nozzle holes. The predicted fuel efficiency benefit of Design 2 was found to be more pronounced at low to medium loads.

Modeling of Compressed Air Hybrid Operation for a Heavy Duty Diesel Engine

2008 ◽  
Author(s):  
Xiaoyong Wang ◽  
Tsu-Chin Tsao ◽  
Chun Tai ◽  
Hyungsuk Kang ◽  
Paul N. Blumberg
Keyword(s):  
Diesel Engine ◽  
Fuel Economy ◽  
Internal Combustion Engines ◽  
Compressed Air ◽  
Valve Timing ◽  
Heavy Duty ◽  
Vehicle Simulation ◽  
Heavy Duty Diesel Engine ◽  
Fuel Economy Improvement ◽  
Heavy Duty Diesel

Internal combustion engines can be modified to operate regenerative braking cycles by using compressed air power. This paper presents a particular air hybridization design from among many possible configurations. The engine cycles are enabled by a highly flexible engine valvetrain, which actuates engine valves to generate desired torque with optimal efficiency. A lumped parameter model is developed first to investigate the cylinder-tank mass and energy interaction based on thermodynamic relationships and engine piston kinematics. Special consideration is given to the engine valve timing and air flow. A high fidelity, detailed model using the commercially available GT-Power software is developed for a commercial 10.8 liter heavy-duty diesel engine with a 280 liter air tank in order to capture the effects of engine friction, heat transfer, gas dynamics, etc. The model is used to develop optimal valve timing for engine control. The established engine maps are incorporated into the ADVISOR vehicle simulation package to evaluate the potential fuel economy improvement for a refuse truck under a variety of driving cycles. Depending on the particular driving cycle, the simulation has shown a potential 4% – 18% fuel economy improvement over the truck equipped with the conventional baseline diesel engine.

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