Effect of addition of hydrogen and TiO2 in gasoline engine in various exhaust gas recirculation ratio

We investigate control strategies for traditional throttle-in-bore as well as low-cost cartridge-style throttle bodies for the air-intake system (AIS) throttle used in low-pressure exhaust-gas recirculation (LPEGR) on a turbocharged gasoline engine. Pressure sensors placed upstream and downstream of the AIS throttle are available as signals from the vehicle’s engine control unit, however, we do not use high-bandwidth feedback control of the AIS throttle in order to maintain frequency separation from the higher-rate EGR loop, which uses the downstream pressure sensor for feedback control. A design-of-experiments conducted using a feed-forward lookup table-based AIS throttle control strategy exposes controller sensitivity to part-to-part variations. For accurate tracking in the presence of these variations, we explore the use of adaptive feedback control. In particular, we use an algebraic model representing the throttle plate effective opening area to develop a recursive least-squares (RLS)-based estimation routine. A low-pass filtered version of the estimated model parameters is subsequently used in the forward-path AIS throttle controller. Results are presented comparing the RLS-based feedback algorithm with the feed-forward lookup table-based control strategy. RLS is able to adapt for part-to-part and change-over-time variabilities and exhibits an improved steady-state tracking response compared to the feed-forward control strategy.

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Effect of exhaust gases of Exhaust Gas Recirculation (EGR) coupling lean-burn gasoline engine on NOx purification of Lean NOx trap (LNT)

Mechanical Systems and Signal Processing ◽

10.1016/j.ymssp.2015.12.029 ◽

2017 ◽

Vol 87 ◽

pp. 195-213 ◽

Cited By ~ 15

Author(s):

Lei Liu ◽

Zhijun Li ◽

Shiyu Liu ◽

Boxi Shen

Keyword(s):

Gasoline Engine ◽

Exhaust Gas Recirculation ◽

Lean Nox Trap ◽

Exhaust Gas ◽

Nox Trap ◽

Lean Burn ◽

Exhaust Gases ◽

Lean Nox ◽

Gas Recirculation

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The effects of exhaust gas recirculation on NOx storage pathway

E3S Web of Conferences ◽

10.1051/e3sconf/202126801017 ◽

2021 ◽

Vol 268 ◽

pp. 01017

Author(s):

Jin Zhao ◽

Zhijun Li ◽

Shilong Li ◽

Shijin Shuai ◽

Shiyu Liu ◽

...

Keyword(s):

Storage Capacity ◽

Gasoline Engine ◽

Exhaust Gas Recirculation ◽

Exhaust Gas ◽

Storage Process ◽

Lean Burn ◽

Langmuir Hinshelwood Mechanism ◽

Nitrate And Nitrite ◽

Increasing Temperature ◽

Gas Recirculation

A LNT (lean NOx trap) model coupled with EGR (exhaust gas recirculation) was developed based on the Langmuir–Hinshelwood mechanism to investigate the EGR effects on NOx adsorption pathway of LNT catalysts with temperature changed in range 150℃~550℃. Both the nitrate and nitrite adsorption paths were considered for the NOx storage process in the model as well as the spillover of stored NOx between Ba and Pt sites. The data and validation for modelling were from literatures of predecessors and our previous lean-burn gasoline engine experiment*. The model quantified the contributions of both nitrate route and nitrite route to the NOx storage with change of EGR rate (0%~30%) under raw emission atmosphere from tested gasoline engine. The model captured key feature of different trends of nitrate route and nitrite route with increasing temperature (150℃~550℃) under EGR rate varying from 0% to 25%. The LNT model provided insight of reaction mechanism for interpreting the behaviour of NOx storage with change of GER rate and temperature, which contributed to improve the NOx storage capacity when mapping EGR rate for lean-burn engine and catalyst operation strategy optimization.

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Experimental study on the effect of high-pressure and low-pressure exhaust gas recirculation on gasoline engine and turbocharger

Advances in Mechanical Engineering ◽

10.1177/1687814018809607 ◽

2018 ◽

Vol 10 (11) ◽

pp. 168781401880960 ◽

Cited By ~ 3

Author(s):

Xianqing Shen ◽

Kai Shen ◽

Zhendong Zhang

Keyword(s):

High Pressure ◽

Fuel Consumption ◽

Gasoline Engine ◽

Exhaust Gas Recirculation ◽

Low Pressure ◽

Operating Conditions ◽

Exhaust Gas ◽

Partial Load ◽

Recirculation System ◽

Gas Recirculation

The effects of high-pressure and low-pressure exhaust gas recirculation on engine and turbocharger performance were investigated in a turbocharged gasoline direct injection engine. Some performances, such as engine combustion, fuel consumption, intake and exhaust, and turbocharger operating conditions, were compared at wide open throttle and partial load with the high-pressure and low-pressure exhaust gas recirculation systems. The reasons for these changes are analyzed. The results showed EGR system of gasoline engine could optimize the cylinder combustion, reduce pumping mean effective pressure and lower fuel consumption. Low-pressure exhaust gas recirculation system has higher thermal efficiency than high-pressure exhaust gas recirculation, especially on partial load condition. The main reasons are as follows: more exhaust energy is used by the turbocharger with low-pressure exhaust gas recirculation system, and the lower exhaust gas temperature of engine would optimize the combustion in cylinder.

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In-Cylinder CO2 Sampling Using Skip-Firing Method

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4043396 ◽

2019 ◽

Vol 141 (8) ◽

Author(s):

Matthew Duckhouse ◽

Mark Peckham ◽

Byron Mason ◽

Edward Winward ◽

Matthew Hammond

Keyword(s):

Response Time ◽

Gasoline Engine ◽

Wide Band ◽

Exhaust Gas Recirculation ◽

Fast Response ◽

Firing Cycle ◽

Exhaust Gas ◽

Engine Operation ◽

Gas Recirculation ◽

Firing Method

Skip-firing (or cylinder de-activation) was assessed as a method of sampling CO2 directly in the cylinder at higher speeds than previously possible. CO2 was directly sampled from one cylinder of a 1 L three-cylinder gasoline engine to determine the residual gas fraction (RGF) using a fast response CO/CO2 analyzer. Acquisition of data for similar measurements is typically limited to engine speeds of below 1300 revolutions per minute (rpm) to allow full resolution of the sample through the analyzer that has an 8 ms finite response time. In order to sample in-cylinder CO2 at higher engine speeds, a skip-firing method is developed. By shutting off ignition intermittently during engine operation, the residual CO2 from the last firing cycle can be measured at significantly higher engine speeds. Comparison of RGF CO2 at low speeds for normal and skip-fire operation shows good correlation. This suggests that skip-firing is a suitable method for directly measuring internal exhaust gas recirculation up to at least 3000 rpm. The measurements obtained may provide a useful tool for validating internal exhaust gas recirculation models and could be used to calculate combustion air–fuel ratio from the CO and CO2 content of the burned gas. These are typically complicated parameters to predict due to the slow response time and sensitivity to hydrocarbons of wide-band oxygen sensors. A differing pattern of RGF change with increasing speed was seen between normal and skip-fire operation.

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