Exhaust Temperature Management for Diesel Engines Assessment of Engine Concepts and Calibration Strategies with Regard to Fuel Penalty

Author(s):  
Sharareh Honardar ◽  
Hartwig Busch ◽  
Thorsten Schnorbus ◽  
Christopher Severin ◽  
Andreas F. Kolbeck ◽  
...  
Author(s):  
D. Gardiner ◽  
M. LaViolette ◽  
W. D. Allan ◽  
G. Wang ◽  
M. F. Bardon

This paper describes experimental research aimed at developing techniques for monitoring the growth of combustion chamber deposits in diesel engines using data obtained from cylinder pressure and exhaust temperature measurements. A naturally aspirated single cylinder research engine was operated alternately between low load “coking” conditions (2.5 bar BMEP) and higher load “decoking” conditions (5.5 bar BMEP) intended to promote the formation and removal, respectively of combustion chamber deposits. The polytropic exponent of compression was observed to increase during coking runs and decrease during decoking runs. The peak heat release rate was observed to decrease during coking runs and increase during decoking runs. The peak cycle value of the first derivative of the exhaust thermocouple signal decreased during coking runs but exhibited no clear trend during decoking runs. Conventional exhaust temperature measurements showed no consistent trend during coking runs but the exhaust temperature decreased during decoking runs.


1997 ◽  
Vol 119 (2) ◽  
pp. 129-136 ◽  
Author(s):  
P. G. Hill ◽  
B. Douville

A multizone thermodynamic method has been developed to determine combustion rate and NO formation from measured cylinder pressures and performance of two-stroke diesel engines. Integral to the analytical method is a nonlinear fit to the combustion chamber heat loss; the fit is consistent with the overall energy balance and with measured fuel consumption rate and exhaust temperature. The method assumes equilibrium combustion properties except for NO, whose relatively slow formation is estimated using the extended Zeldovich mechanism in the post-flame gas during a period of one mixing time. Application of the method to a 2-stroke diesel engine indicates a post-flame mixing time of 0.55 ms or 4 deg crank angle at 1250 rpm, yielding exhaust concentrations of NO considerably less than what would have been expected from equilibrium-then-sudden-freezing considerations.


Author(s):  
Thomas Körfer ◽  
Hartwig Busch ◽  
Andreas Kolbeck ◽  
Christopher Severin ◽  
Thorsten Schnorbus ◽  
...  

Both, the continuous tightening of the exhaust emission standards and the global efforts for a significant lowering of CO2 output in public traffic display significant developments for future diesel engines. These engines will utilize not only the mandatory Diesel oxidation catalyst (DOC) and particulate trap (DPF), but also a DeNOx aftertreatment system as well — at least for heavier vehicles. The DOC as well as actually available sophisticated DeNOx aftertreatment technologies, i.e. LNT and SCR, depends on proper exhaust gas temperatures to achieve a high conversion rates. This aspect becomes continuously critical due to intensified measures for CO2 reduction, which will conclude in a drop of exhaust gas temperatures. Furthermore, this trend has to be taken into account regarding future electrification and hybridization scenarios. In order to ensure the high NOx conversion rates in the EAS intelligent temperature management strategies will be required, not only based on conventional calibration measures, but also a further upgrade of the engine hardware. Advanced split-cooling and similar thermal management technologies offer the merit to lower CO2 emissions on one hand and increase exhaust gas temperature at cold start and warm-up simultaneously on the other hand. Besides this, also variable valve train functionalities deliver a substantial potential of active thermal management. In the context of this paper various concepts for exhaust gas temperature management are investigated and compared. The final judgment will focus on the effectiveness concerning real exhaust temperature increase vs. corresponding fuel economy penalty. Further factors, like operational robustness, consequences on operational strategies and related software algorithms as well as cost are assessed. The utilized reference engine in this advanced program is represented by a refined I-4 research engine to achieve best combustion efficiency at minimal engine-out emissions. The detailed studies were performed with an injection strategy, featuring one pilot injection and one main injection event, and an active, advanced closed-loop combustion control. The engine used in this study allows fulfillment of Euro 6 and Tier 2 Bin 5 emissions standards, while offering high power densities above 80 kW/ltr. As a résumé, it can be stated, that with all accomplished variations a significant increase in temperature downstream low pressure turbine can be achieved. The PI and PoI quantities define dominant parameters for emission formation under cold and warm conditions. By using an exhaust cam-phaser CO-, HC- and NOx emissions can be significantly lowered, separating VVT functions from the other investigated strategies.


2009 ◽  
Vol 36 (S 02) ◽  
Author(s):  
J Peterson

Author(s):  
Serhii Kovalov

The expediency of using vehicles of liquefied petroleum gas as a motor fuel, as com-pared with traditional liquid motor fuels, in particular with diesel fuel, is shown. The advantages of converting diesel engines into gas ICEs with forced ignition with respect to conversion into gas diesel engines are substantiated. The analysis of methods for reducing the compression ratio in diesel engines when converting them into gas ICEs with forced ignition has been carried out. It is shown that for converting diesel engines into gas ICEs with forced ignition, it is advisable to use the Otto thermo-dynamic cycle with a decrease in the geometric degree of compression. The choice is grounded and an open combustion chamber in the form of an inverted axisymmetric “truncated cone” is developed. The proposed shape of the combustion chamber of a gas internal combustion engine for operation in the LPG reduces the geometric compression ratio of D-120 and D-144 diesel engines with an unseparated spherical combustion chamber, which reduces the geometric compression ratio from ε = 16,5 to ε = 9,4. The developed form of the combustion chamber allows the new diesel pistons or diesel pistons which are in operation to be in operation to be refined, instead of making special new gas pistons and to reduce the geometric compression ratio of diesel engines only by increasing the combustion chamber volume in the piston. This method of reducing the geometric degree of compression using conventional lathes is the most technologically advanced and cheap, as well as the least time consuming. Keywords: self-propelled chassis SSh-2540, wheeled tractors, diesel engines D-120 and D-144, gas engine with forced ignition, liquefied petroleum gas (LPG), compression ratio of the internal com-bustion engine, vehicles operating in the LPG.


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