Cooling system improvements — assessing the effects on emissions and fuel economy

Brace, Chris; Hawley, J G; Akehurst, Sam; Piddock, Mitchell; Pegg, Ian

doi:10.1243/09544070jauto685

Cited by 39 publications

(24 citation statements)

References 14 publications

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“…They also pointed out the complexity of and the lack of comprehensive studies on thermal effects on combustion. Brace et al 8 tested several cooling system modifications and showed a fuel economy benefit of around 2%, accompanied by an NOx penalty between 12% and 45% under steady operating conditions. Smaller effects were observed in the driving cycle (a 0.4% fuel economy benefit and a 10% NOx increase).…”

Section: Introductionmentioning

confidence: 99%

Experimental analysis of the influence of coolant and oil temperature on combustion and emissions in an automotive diesel engine

Tauzia

Maiboom

Karaky

et al. 2018

International Journal of Engine Research

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Since many trips are of short duration and include a cold start, automotive engines run quite often without having reached their nominal temperature. This is known to have some major drawbacks, such as increased fuel consumption and higher emissions due to lower efficiency of after-treatment devices, but detailed description of these various effects is seldom presented in the literature. In this article, experiments were conducted on an automotive diesel engine by varying independently the coolant and oil temperatures between 30°C and 90°C. Three different operating conditions (low, mid and full load) were studied. The experimental setup is briefly described as well as the uncertainty of the associated measurements and the development of analytic tools. Then, the evolution of volumetric efficiency, energy share, combustion heat release and exhaust emissions (NOx, particulate matter, CO, unburned hydrocarbons) are described in detail and analysed. Several strategies were considered, including some corrections used in the standard engine control unit to compensate for the low coolant temperature. Some effects of the coolant and oil temperature reduction were clear: increase in friction losses, volumetric efficiency and ignition delay and decrease in NOx emissions. On the contrary, the evolution of brake thermal efficiency, particulate matter, CO and unburned hydrocarbon emission depended on the operating point.

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Section: Introductionmentioning

confidence: 99%

Experimental analysis of the influence of coolant and oil temperature on combustion and emissions in an automotive diesel engine

Tauzia

Maiboom

Karaky

et al. 2018

International Journal of Engine Research

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“…The temperature of the cooling system coolant was recorded during an urban driving cycle for both upper and lower radiator tanks (down flow radiator). The results showed significant differences between the two readings, as described in detail in ref [14].…”

Section: Experimental Apparatusmentioning

confidence: 57%

The Effect of Using a Modified A/C System on the Cooling System Temperature of an Internal Combustion Engine

Morad¹,

Alnaqi²,

Murad³

et al. 2017

IJERA

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This study investigates the effect of using A/C refrigerant to reduce the temperature of the coolant in a vehicle cooling system. An increase in coolant temperature due to harsh working conditions increases fuel consumption and leads to a reduction in engine power. Modifying vehicle air-conditioning by passing the suction line of the A/C system through the heat exchanger located in the lower part of the radiator (down flow type) can significantly improve the performance of the engine cooling system. The results show a reduction in the temperature of coolant within the cooling system, thus maintaining a controlled working temperature within the allowable limits.

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“…This component is also a wax element device but is sensitive to both the top-hose coolant temperature and the bottom-hose coolant temperature, meaning that it can react to the cooling potential over the radiator. 8 The active TMS included the following:…”

Section: Methodsmentioning

confidence: 99%

“…Some active systems are only beneficial under fully warm conditions and do not offer any benefits during warm-up because they do not change the available energy per unit thermal mass. [7][8][9] To achieve benefits during warm-up, either reduced inertia or heat addition must occur. 6 Careful placing of coolant control valves can improve the engine behaviour during warm-up by isolating parts of the circuit and effectively reducing the thermal inertia during warm-up.…”

Section: Introductionmentioning

confidence: 99%

Systems optimisation of an active thermal management system during engine warm-up

Burke

Lewis

Brace

et al. 2012

Proceedings of the Institution of Mechanical Engineers, Part D:

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Active thermal management systems offer a potential for small improvements in fuel consumption that will contribute to upcoming legislation on carbon dioxide emissions. These systems offer new degrees of freedom for engine calibration; however, their full potential will only be exploited if a systems approach to their calibration is adopted, in conjunction with other engine controls. In this work, a design-of-experiments approach is extended to allow its application to transient drive cycles performed on a dynamic test stand. Experimental precision is of crucial importance in this technique since even small errors would obscure the effects of interest. The dynamic behaviour of the engine was represented mathematically in a manner that enabled conventional steady state modelling approaches to be employed in order to predict the thermal state of critical parts of the engine as a function of the actuator settings. A 17-point test matrix was undertaken, and subsequent modelling and optimisation procedures indicated potential 2-3% fuel consumption benefits under iso-nitrogen oxide conditions. Reductions in the thermal inertia appeared to be the most effective approach for reducing the engine warm-up time, which translated approximately to a 1.3% reduction in the fuel consumption per kilogram of coolant. A novel oil-cooled exhaust gas recirculation system showed the significant benefits of cooling the exhaust gases, thereby reducing the inlet gas temperature by 5°C and subsequently the nitrogen oxide emissions by 6%, in addition to increasing the warm-up rate of the oil. This suggested that optimising the thermal management system for cooling the gases in the exhaust gas recirculation system can offer significant improvements. For the first time this paper presents a technique that allows simple predictive models of the thermal state of the engine to be integrated into the calibration process in order to deliver the optimum benefit. In particular, it is shown how the effect of the thermal management system on the nitrogen oxides can be traded off, by advancing the injection timing, to give significant improvements in the fuel consumption.

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Cooling system improvements — assessing the effects on emissions and fuel economy

Cited by 39 publications

References 14 publications

Experimental analysis of the influence of coolant and oil temperature on combustion and emissions in an automotive diesel engine

Experimental analysis of the influence of coolant and oil temperature on combustion and emissions in an automotive diesel engine

The Effect of Using a Modified A/C System on the Cooling System Temperature of an Internal Combustion Engine

Systems optimisation of an active thermal management system during engine warm-up

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