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A Dynamic Method to Analyze Cold-Start First Cycles Engine-Out Emissions at Elevated Cranking Speed Conditions of a Hybrid Electric Vehicle Including a Gasoline Direct Injection Engine
- Amir A. Khameneian - Michigan Technological University, Mechanical Engineering-Engineering Mechanics, USA ,
- Behrouz K. Irdmousa - Michigan Technological University, USA ,
- Paul Dice - Michigan Technological University, USA ,
- Mahdi Shahbakhti - University of Alberta, Canada ,
- Jeffrey D. Naber - Michigan Technological University, USA ,
- Peter Moilanen - Ford Motor Company, USA ,
- Chad Archer - Ford Motor Company, USA ,
- Chris Glugla - Ford Motor Company, USA ,
- Garlan Huberts - Ford Motor Company, USA
Journal Article
03-15-06-0044
ISSN: 1946-3936, e-ISSN: 1946-3944
Sector:
Topic:
Citation:
Khameneian, A., K. Irdmousa, B., Dice, P., Shahbakhti, M. et al., "A Dynamic Method to Analyze Cold-Start First Cycles Engine-Out Emissions at Elevated Cranking Speed Conditions of a Hybrid Electric Vehicle Including a Gasoline Direct Injection Engine," SAE Int. J. Engines 15(6):807-823, 2022, https://doi.org/10.4271/03-15-06-0044.
Language:
English
Abstract:
The cold crank-start stage, including the first three engine cycles, is
responsible for a significant amount of the cold-start phase emissions in a
Gasoline Direct Injection (GDI) engine. The engine crank-start is highly
transient due to substantial engine speed changes, Manifold Absolute Pressure
(MAP) dynamics, and in-cylinder temperatures. Combustion characteristics change
depending on control inputs variations, including throttle angle and spark
timing. Fuel injection strategy, timing, and vaporization dynamics are other
parameters causing cold-start first cycles analysis to be more complex. Hybrid
Electric Vehicles (HEVs) provide elevated cranking speed, enabling technologies
such as cam phasing to adjust the valve timing and throttling, and increased
fuel injection pressure from the first firings. To analyze the engine-out
emissions, including unburnt Hydrocarbon (HC), Nitrogen Oxides (NOx), Carbon
monoxide (CO), and Carbon dioxide (CO2), the measured emissions in
mole fraction need to be quantified in mass per cycle per cylinder considering
all dynamics mentioned above. This study proposes a new method to quantify
individual-cylinder engine-out emissions event by event dynamically. The method
consists of the individual-cylinder GT-Power Three Pressure Analysis (TPA),
in-cylinder parameters estimation, fuel vaporization Computational Fluid
Dynamics (CFD) analysis, and exhaust gas dynamics in the exhaust manifold.
Experimental MAP, cylinder and exhaust pressures, injection pulse width,
GT-Power estimated parameters, and air mass flow meter data are used for the new
method calibration and validation. The estimated trapped air charge and the
equivalent combusted fuel masses are the most critical parameters affecting the
precision of calculating engine-out emissions on a mass basis. The results show
that the trapped air charge is estimated with a 2.7 mg average error. In
addition, the simulated Indicated Mean Effective Pressure (IMEP) as
representative of the mass of fuel contributed to the combustion during the same
event was validated with a 0.06 bar average error. Furthermore, the fuel path
analysis is carried out to validate the post-oxidization coefficient and lost
fuel portion calibrated values, showing 75.3% and 15.8% post-oxidization rate of
unburnt HC and 18.5% and 20% lost fuel portion for high cranking speed/highly
retarded and low cranking speed/advanced spark timing conditions,
respectively.