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Technical Paper

Effect of Port Water Injection on the Knock and Combustion Characteristics for an Argon Power Cycle Hydrogen Engine

2024-04-09
2024-01-2612
Argon power cycle hydrogen engine is an internal combustion engine that employs argon instead of nitrogen of air as the working fluid, oxygen as the oxidizer, and hydrogen as the fuel. Since argon has a higher specific heat ratio than air, argon power cycle hydrogen engines have theoretically higher indicated thermal efficiencies according to the Otto cycle efficiency formula. However, argon makes the end mixture more susceptible to spontaneous combustion and thus is accompanied by a stronger knock at a lower compression ratio, thus limiting the improvement of thermal efficiency in engine operation. In order to suppress the limitation of knock on the thermal efficiency, this paper adopts a combination of experimental and simulation methods to investigate the effects of port water injection on the knock suppression and combustion characteristics of an argon power cycle hydrogen engine.
Technical Paper

Knock Inhibition in Hydrogen Fueled Argon Power Cycle Engine with a Higher Compression Ratio by Water Direct Injection at Late Exhaust Stroke

2023-04-11
2023-01-0227
Hydrogen-fueled Argon Power Cycle engine is a novel concept for high efficiency and zero emissions, which replaces air with argon/oxygen mixtures as working fluid. However, one major challenge is severe knock caused by elevated in-cylinder temperature resulting from high specific heat ratio of Argon. A typical knock-limited compression ratio is around 5.5:1, which limits the thermal efficiency of Argon Power Cycle engines. In this article, preliminary experimental research on the effect of water direct injection at late exhaust stroke is presented at 1000 r/min with IMEP ranging from 0.3~0.6 MPa. Results show that, with temperature-reducing effect of water evaporation, knock is greatly inhibited and the engine can run normally at a higher compression ratio of 9.6:1. Water injected at the exhaust stroke minimizes its reducing effect on the specific heat ratio of the working fluid during the compression and expansion strokes.
Technical Paper

Numerical Study on Flammability Limit and Performance of Compression-Ignition Argon Power Cycle Engine with Fuel of Hydrogen

2021-04-06
2021-01-0391
The argon power cycle engine, which uses hydrogen as fuel, oxygen as oxidant, and argon other than nitrogen as the working fluid, is considered as a novel concept of zero-emission and high-efficiency system. Due to the extremely high in-cylinder temperature caused by the lower specific heat capacity of argon, the compression ratio of spark-ignition argon power cycle engine is limited by preignition or super-knock. Compression-ignition with direct-injection is one of the potential methods to overcome this challenge. Therefore, a detailed flammability limit of H2 under Ar-O2 atmosphere is essential for better understanding of stable autoignition in compression-ignition argon power cycle engines.
Technical Paper

Starting Process Control of a 2-Cylinder PFI Gasoline Engine for Range Extender

2020-04-14
2020-01-0315
With the increasing worldwide concern on environmental pollution, battery electrical vehicles (BEV) have attracted a lot attention. However, it still couldn’t satisfy the market requirements because of the low battery power density, high cost and long charging time. The range-extended electrical vehicle (REEV) got more attention because it could avoid the mileage anxiety of the BEVs with lower cost and potentially higher efficiency. When internal combustion engine (ICE) works as the power source of range extender (RE) for REEV, its NVH, emissions in starting process need to be optimized. In this paper, a 2-cylinder PFI gasoline engine and a permanent magnet synchronous motor (PMSM) are coaxially connected. Meanwhile, batteries and load systems were equipped. The RE co-control system was developed based on Compact RIO (Compact Reconfigurable IO), Labview and motor control unit (MCU).
Technical Paper

Thermodynamic and Chemical Analysis of the Effect of Working Substances on the Argon Power Cycle

2021-04-06
2021-01-0447
The Argon Power Cycle engine is a novel concept for high efficiency and zero emission through the replacement of N2 by Ar. However, the higher in-cylinder temperature and pressure as by-products cause heavier knock. The anti-knock strategies, such as reducing compression ratio and retarding ignition time, offset the efficiency increased by the Argon Power Cycle. Therefore, knock control becomes the most urgent task for the Argon Power Cycle engine development. The anti-knock methods, including fuel replacement, ultra-lean combustion, high dilution combustion, and water injection, were considered. The simulated ignition delay times were used to evaluate the probability of knock. The Otto cycle, combined with chemical equilibrium, was utilized to confirm the effect on the thermal conversion efficiency and each in-cylinder thermodynamic state parameter. The results show that the ignition delay times increase by a factor of two when the Ar dilution ratio increases from 79% to 95%.
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