A Torque Balance Method for Multi-Cylinder Gasoline Engines With Non-Uniform Cylinder-to-Cylinder Combustion Strategies

2019 ◽  
Author(s):  
Qinghua Lin ◽  
Pingen Chen
Keyword(s):  
Catalytic Reduction ◽  
Control Strategies ◽  
Fuel Efficiency ◽  
The United States ◽  
Nox Emission ◽  
Successful Implementation ◽  
Lean Burn ◽  
Gasoline Engines ◽  
Engine Model ◽  
Lean Nox

Abstract Lean burn gasoline engines have attracted more and more attentions over the past two decades. One of the main challenges in commercializing lean burn gasoline engines in the United States is lean NOx control to meet the stringent NOx emission regulation. Several types of lean aftertreatment systems including passive selective catalytic reduction (SCR) systems and lean NOx traps (LNTs), have been intensively investigated to meet the NOx emission requirements without triggering significant penalties on fuel efficiency. One of the most promising technologies to achieve this goal is non-uniform cylinder-to-cylinder combustion (NUCCC) control strategies. However, successful implementation of NUCCC strategies are challenging tasks since it may cause cylinder-to-cylinder torque imbalance and thus deterioration of drivability. The purpose of this study is to propose and evaluate a systematic method for generating the references of fuel quantity and air quantity for different cylinders to simultaneously achieve cylinder-to-cylinder torque balance and non-uniform cylinder-to-cylinder air/fuel ratio (AFR) for multi-cylinder engines in various scenarios. To validate the effectiveness of the proposed method, simulation studies were carried out using a multi-zone engine model. The simulation results show that, the proposed references, if successfully tracked, can lead to torque balance across the cylinders as well as non-uniform cylinder-to-cylinder AFR.

Configuration and Control Design for a Passive SCR System With NOx Storage Capability

2018 ◽  
Author(s):  
Qinghua Lin ◽  
Pingen Chen ◽  
Vitaly Y. Prikhodko ◽  
James E. Parks
Keyword(s):  
Catalytic Reduction ◽  
Nox Reduction ◽  
Cost Effective ◽  
Nox Storage ◽  
Lean Burn ◽  
Gasoline Engines ◽  
Generation Cost ◽  
Lean Nox ◽  
Scr System ◽  
Passive Scr

Passive selective catalytic reduction (SCR) systems have been considered as a promising technology for reducing NOx emissions for highly-efficient lean burn gasoline engines. Since passive SCR requires intermittent rich operation for self-generating ammonia (NH3) for NOx reduction in the lean phase, the fuel penalty associated with NH3 generation may be significant. To address this issue, a new prototype passive SCR system with NOx storage capability was recently investigated. The three-way catalyst (TWC) with added NOx storage capability is able to enhance NH3 production rate by utilizing pre-stored NOx and thus reduce the fuel cost related to NH3 production. The main purpose of this study is to reduce the ammonia generation cost by: 1) proposing a new passive SCR system architecture that includes two TWC stages; and 2) developing and optimizing a novel non-uniform cylinder-to-cylinder combustion (NUCCC) control. Optimization results based on the experimental data from a physical engine platform, demonstrate that the new passive SCR system (with NOx storage components on TWCs), in conjunction with optimized NUCCC control, is capable of reducing ammonia specific fuel consumption (ASFC) by 30.2%, when compared to a uniform cylinder-to-cylinder combustion (UCCC)-controlled baseline passive SCR system. Such a novel NUCCC control and innovative passive SCR configuration, will be very instrumental in creating cost-effective lean NOx emission control solutions for lean-burn engines in the future.

Control Design of an Automotive Urea SCR Catalyst

2002 ◽  
Author(s):  
Devesh Upadhyay ◽  
Michiel Van Nieuwstadt
Keyword(s):  
Ammonia Oxidation ◽  
Catalytic Reduction ◽  
Nox Reduction ◽  
Control Design ◽  
Reaction Rates ◽  
Lumped Parameter Model ◽  
Lean Burn ◽  
Ammonia Sensing ◽  
Injection Process ◽  
Lean Nox

The leading aftertreatment technologies for NOx removal from the exhaust gas of lean burn engines, Diesels in particular, are urea based Selective Catalytic Reduction (SCR), Lean NOx Traps (LNT) and Active Lean NOx Catalysts (ALNC). It is generally believed that the SCR technique has the potential of providing the best NOx conversion efficiency relative to the other techniques. Nonetheless, it is crucial that the high conversion efficiencies be achieved with a minimum slippage of unreacted ammonia as tail pipe emissions. This necessitates a precise control over the urea injection process. The complex behavior of the catalyst substrate with respect to adsorption and desorption of ammonia in conjunction with a lack of “stored ammonia” sensing capabilities makes the control problem challenging. In this paper we present a model-based control design approach using a lumped parameter model of an SCR system that includes the essential dynamics of the plant. The model includes the adsorption, desorption and surface coverage dynamics, along with the NOx reduction and ammonia oxidation dynamics based on the relevant chemical reaction rates.

Two-Stage Turbocharging Solutions for Tier 4 Rail Applications

2015 ◽  
Author(s):  
Simone Bernasconi ◽  
Ennio Codan ◽  
David Yang ◽  
Pierre Jacoby ◽  
German Weisser
Keyword(s):  
Catalytic Reduction ◽  
Fuel Efficiency ◽  
Engine Performance ◽  
Ambient Conditions ◽  
Two Stage ◽  
Optimum Performance ◽  
Engine Model ◽  
High Fuel Efficiency ◽  
Wide Range ◽  
Turbocharging System

With the introduction of the EPA Tier 4 NOx emission limits for rail diesel engines this year, engine developers are forced to implement more advanced emission control technologies such as selective catalytic reduction (SCR) or cooled external exhaust gas recirculation (EGR). The integration and control of these systems for ensuring optimum performance throughout the operating range brings about new challenges on top of the well-known requirement for unconstrained operability in a very wide range of conditions. As a consequence, engines and their subsystems have to be designed for maximum flexibility. The turbocharging system in particular needs to be capable of dealing with extreme ambient conditions associated with high altitudes, hot summers, severe winters, tunnel operation, etc. This flexibility must be achieved without compromising reliability and while ensuring continuous in-use compliance with the emissions standards throughout the life of the installation. At the same time, engine performance should be maintained at the highest level possible. This study demonstrates that all of these targets can be met by combining two-stage turbocharging and EGR with suitable control elements. Two-stage turbocharging, which has become increasingly popular in other industry sectors due to its potential for improving the bsfc / NOx emissions trade-off when used in combination with correspondingly optimized valve actuation (Miller timing), is starting to be adopted also for rail applications. A variety of EGR concepts was proposed or put into practice over the past few years, and the most important or promising of these have been taken into consideration for this study. Extensive simulations of the resulting engine and turbocharging systems have been performed using ABB’s in-house simulation platform, based on a generic engine model that can be considered representative of the rail sector. It is shown that integration of EGR, two-stage turbocharging and appropriate control elements is highly attractive as it offers outstanding operational flexibility and very high fuel efficiency without any compromise in terms of reliability. The selection and specification of control elements and turbocharging system components depends on the EGR concept applied. As is shown below, this can be tailored to the application to ensure optimum performance and flexibility. In view of these obvious benefits, we are very confident that such integrated EGR / two-stage turbocharging systems will be adopted more widely on railway engines.

scholarly journals Measures to Reduce the N2O Formation at Perovskite-Based Lean NOx Trap Catalysts under Lean Conditions

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 917
Author(s):  
Sabrina I. Ecker ◽  
Jürgen Dornseiffer ◽  
Stefan Baumann ◽  
Olivier Guillon ◽  
Henny J. M. Bouwmeester ◽  
...  
Keyword(s):  
Catalytic Reduction ◽  
Operation Mode ◽  
Oxidation Catalyst ◽  
Lean Nox Trap ◽  
N2o Emissions ◽  
Incipient Wetness Impregnation ◽  
N2o Formation ◽  
Lean Burn ◽  
Nox Storage Capacity ◽  
Lean Nox

The net oxidising atmosphere of lean burn engines requires a special after-treatment catalyst for NOx removal from the exhaust gas. Lean NOx traps (LNT) are such kind of catalysts. To increase the efficiency of LNTs at low temperatures platinised perovskite-based infiltration composites La0.5Sr0.5Fe1-xMxO3-δ/Al2O3 with M = Nb, Ti, Zr have been developed. In general, platinum based LNT catalysts show an undesired, hazardous formation of N2O in the lean operation mode due to a competing C3H6-selective catalytic reduction (SCR) at the platinum sites. To reduce N2O emissions an additional Rh-coating, obtained by incipient wetness impregnation, besides the Pt coating and a two-layered oxidation catalyst (2 wt.% Pd/20 wt.% CeO2/alumina)-LNT constitution, has been investigated. Though the combined Rh-Pt coating shows a slightly increased NOx storage capacity (NSC) at temperatures above 300 °C, it does not decrease N2O formation. The layered oxidation catalyst-LNT system shows a decrease in N2O formation of up to 60% at 200 °C, increasing the maximum NSC up to 176 µmol/g. Furthermore, the NSC temperature range is broadened compared to that of the pure LNT catalyst, now covering a range of 250–300 °C.

scholarly journals Research on Metal Doped Zeolite as Catalyst to Reduce NOX Emission from Lean Burn Gasoline Engines

2019 ◽  
Vol 8 (5S3) ◽  
pp. 201-206 ◽  
Keyword(s):  
Gasoline Engine ◽  
Fuel Injection ◽  
Catalytic Converter ◽  
Nox Emission ◽  
Gasoline Direct Injection ◽  
Oxidation Catalyst ◽  
Gas Temperature ◽  
Lean Burn ◽  
Exchange Method ◽  
Gasoline Engines

Lean burn gasoline direct injection (GDI) engines are the most preferred gasoline engines because of their low fuel consumption and high thermal efficiency. However, these engines produce exhaust gases that are particularly rich in oxygen and therefore the present three-way catalytic converter (TWC) is not suitable for converting the generated NOX emission into Nitrogen gases. In this present work, a new method of reducing Nitrogen Oxides emission in a gasoline engine is attempted by using an ordinary oxidation catalyst together with a deNOX(zeolite-based) catalyst. In this work, Na-form of ZSM-5 zeolite was used as a catalyst and cupric chloride (CuCl2) and ferric chloride (FeCl3) where used as transition metals. Cu-ZSM5 and Fe-ZSM5 catalyst were prepared separately in our laboratory. Na+ ion exchange method is used to prepare the catalyst. After that Cu-ZSM% and Fe- ZSM5 catalyst were washcoated separately onto the blank monoliths. Oxidation monoliths ( for oxidation of CO and HC into CO2 and H2O) were purchased directly from market. One oxidation monolith and one zeolite coated monolith were placed in a stainless steel container and canned with inlet and outlet cones ( forming catalytic convertor ). Experiments were conducted on a 2 cylinder Multi Point Port Fuel Injection engine along with a dynamometer. Exhaust emissions such as NOX, CO, HC, O2, CO2 were measured with AVL Di-gas-444 Analyzer. Exhaust gas temperature is measured with the use of a thermocouple. Firstly load tests (4, 7, 10, 13, and 16KW) were conducted on the engine without catalytic convertor was fixed close to the outlet pipe and the test were conducted again with same loading condition as mentioned above. Then by the same above procedure is followed to conduct test with Cu-ZSM5 and Fe-ZSM5 catalytic convertors. From the results it is observed that both Cu and Fe zeolite catalyst minimize emissions than the commercial catalytic converter.

scholarly journals A New Dawn for Diesel

2005 ◽  
Vol 127 (01) ◽  
pp. 26-31
Author(s):  
John DeGaspari
Keyword(s):  
Fuel Economy ◽  
Fuel Efficiency ◽  
Engine Performance ◽  
The United States ◽  
Heavy Load ◽  
Gasoline Engines ◽  
Fuel Prices ◽  
Personal Use ◽  
The Difference ◽  
Heavy Loads

This article reviews that diesel engines are more expensive than gasoline engines and the lower fuel prices in the United States make buying decisions based on fuel economy alone unlikely. Many of the advancements have gone largely unnoticed by US drivers, who still view diesels as workhorses for large trucks. But some proponents of diesel say that a combination of higher torque, better fuel economy, and smooth, quiet engine performance could sway a significant number of drivers here to consider diesels for smaller, personal-use vehicles. Diesels provide better fuel efficiency than gasoline engines do and are well suited to heavy loads and continuous driving. Hauling a heavy load up a steep grade, the difference in fuel economy could be as high as 75 percent compared to conventional gasoline engines. Diesels could make a bigger impact on fuel consumption from a fleet perspective in this country, where people favor larger vehicles, than in Europe. Diesels deliver higher torque at lower speeds than gasoline engines, allowing drivers to get away with a comparatively smaller, lower horsepower diesel without sacrificing acceleration or towing capacity.

scholarly journals Examination of Metal Doped Zeolite as Catalyst to Reduce NOX Emission from Lean Burn Gasoline Engines

2019 ◽  
Vol 9 (1S) ◽  
pp. 45-50
Keyword(s):  
Gasoline Engine ◽  
Fuel Injection ◽  
Catalytic Converter ◽  
Nox Emission ◽  
Gasoline Direct Injection ◽  
Oxidation Catalyst ◽  
Gas Temperature ◽  
Lean Burn ◽  
Exchange Method ◽  
Gasoline Engines

Lean burn gasoline direct injection (GDI) engines are the most preferred gasoline engines because of their low fuel consumption and high thermal efficiency. However, these engines produce exhaust gases that are particularly rich in oxygen and therefore the present three-way catalytic converter (TWC) is not suitable for converting the generated NOX emission into Nitrogen gases. In this present work, a new method of reducing Nitrogen Oxides emission in a gasoline engine is attempted by using an ordinary oxidation catalyst together with a deNOX(zeolite-based) catalyst. In this work, Na-form of ZSM-5 zeolite was used as a catalyst and cupric chloride (CuCl2 ) and ferric chloride (FeCl3 ) where used as transition metals. Cu-ZSM5 and Fe-ZSM5 catalyst were prepared separately in our laboratory. Na+ ion exchange method is used to prepare the catalyst. After that Cu-ZSM% and Fe- ZSM5 catalyst were washcoated separately onto the blank monoliths. Oxidation monoliths ( for oxidation of CO and HC into CO2 and H2O) were purchased directly from market. One oxidation monolith and one zeolite coated monolith were placed in a stainless steel container and canned with inlet and outlet cones ( forming catalytic convertor ). Experiments were conducted on a 2 cylinder Multi Point Port Fuel Injection engine along with a dynamometer. Exhaust emissions such as NOX, CO, HC, O2 , CO2 were measured with AVL Di-gas-444 Analyzer. Exhaust gas temperature is measured with the use of a thermocouple. Firstly load tests (4, 7, 10, 13, and 16KW) were conducted on the engine without catalytic convertor was fixed close to the outlet pipe and the test were conducted again with same loading condition as mentioned above. Then by the same above procedure is followed to conduct test with Cu-ZSM5 and Fe-ZSM5 catalytic convertors. From the results it is observed that both Cu and Fe zeolite catalyst minimize emissions than the commercial catalytic converter.

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