A new method to warm up lubricating oil to improve the fuel efficiency during cold start

Cold start driving cycles exhibit an increase in friction losses due to the low temperatures of metal and media compared to normal operating engine conditions. These friction losses are responsible for up to 10% penalty in fuel economy over the official drive cycles like the New European Drive Cycle (NEDC), where the temperature of the oil even at the end of the 1180 s of the drive cycle is below the fully warmed up values of between 100°C and 120°C. At engine oil temperatures below 100°C the water from the blow by condensates and dilutes the engine oil in the oil pan which negatively affects engine wear. Therefore engine oil temperatures above 100°C are desirable to minimize engine wear through blow by condensate. The paper presents a new technique to warm up the engine oil that significantly reduces the friction losses and therefore also reduces the fuel economy penalty during a 22°C cold start NEDC. Chassis dynamometer experiments demonstrated fuel economy improvements of over 7% as well as significant emission reductions by rapidly increasing the oil temperature. Oil temperatures were increased by up to 60°C during certain parts of the NEDC. It is shown how a very simple sensitivity analysis can be used to assess the relative size or efficiency of different heat transfer passes and the resulting fuel economy improvement potential of different heat recovery systems system. Due to its simplicity the method is very fast to use and therefore also very cost effective. The method demonstrated a very good correlation for the fuel consumption within ±1% compared to measurements on a vehicle chassis roll

Numerical Analysis of Methane Direct Injection in a Single-cylinder 250 cm3 Spark Ignition Engine

The paper shows the results of the numerical tasks of a study aimed to evaluate the potential of low-pressure (< 20 bar) direct injection systems for internal combustion engines fed with gaseous fuels. Starting from the geometry of a low-cost commercial injector already available for GDI uses, a 2D axisymmetric CFD analyses is performed to assess the influence of injection pressure and valve and seat-valve profiles on jet characteristics, methane-air mixing, and charge distribution at ignition time. Then 3D simulations for the motorcycle single cylinder test-engine are carried out considering as much as possible combustion chamber details and realistic boundary conditions. Although it is possible identifying which operating and geometrical details of injection system are able to support complete mixture homogeneity, this study shows tremendous difficulties, in case of gaseous fuels, to realise satisfactory stratification charges that would be required to obtain satisfactory performance at partial loads

Reassessing the projections of the World Water Development Report

Abstract The 2018 edition of the United Nations World Water Development Report stated that nearly 6 billion peoples will suffer from clean water scarcity by 2050. This is the result of increasing demand for water, reduction of water resources, and increasing pollution of water, driven by dramatic population and economic growth. It is suggested that this number may be an underestimation, and scarcity of clean water by 2050 may be worse as the effects of the three drivers of water scarcity, as well as of unequal growth, accessibility and needs, are underrated. While the report promotes the spontaneous adoption of nature-based-solutions within an unconstrained population and economic expansion, there is an urgent need to regulate demography and economy, while enforcing clear rules to limit pollution, preserve aquifers and save water, equally applying everywhere. The aim of this paper is to highlight the inter-linkage in between population and economic growth and water demand, resources and pollution, that ultimately drive water scarcity, and the relevance of these aspects in local, rather than global, perspective, with a view to stimulating debate

Optimum speed power turbine to recover the exhaust energy of compression ignition diesel and gas engines

The efficiency of internal combustion engines may be improved recovering the fuel energy loss in the exhaust gases or the coolant that is the predominant portion of the fuel energy, being the amount of fuel energy transformed in mechanical energy usually less than 50% in the top efficiency operating points and well below that figure in the other operating points of the load and speed map. This paper consider the opportunity to recover part of the exhaust energy with a power turbine that is operational only when convenient and it is run at optimum speed thanks to a by-pass and a continuously variable transmission link to the crankshaft. The power turbine operates at optimum speed only when producing more power than the power loss for back pressure while permitting temperatures to the downstream after treatment system high enough. Simulations for a 12.8 liters straight 6-cylinder Diesel engine with turbocharger and intercooler show improvements in both the fuel conversion efficiency at medium-to-high speeds and medium-to-high loads

Coupling of a KERS power train and a downsized 1.2TDI diesel or a 1.6TDI-JI H2 engine for improved fuel economies in a compact car

Recovery of braking energy during driving cycles is the most effective option to improve fuel economy and reduce green house gas (GHG) emissions. Hybrid electric vehicles suffer the disadvantages of the four efficiency reducing transformations in each regenerative braking cycle. Flywheel kinetic energy recovery systems (KERS) may boost this efficiency up to almost double values of about 70% avoiding all four of the efficiency reducing transformations from one form of energy to another and keeping the vehicle's energy in the same form as when the vehicle starts braking when the vehicle is back up to speed. With reference to the baseline configuration with a 1.6 liters engine and no recovery of kinetic energy, introduction of KERS reduces the fuel usage to 3.16 liters per 100 km, corresponding to 82.4 g of CO2 per km. The 1.6 liters Turbo Direct Injection (TDI) Diesel engine without KERS uses 1.37 MJ per km of fuel energy, reducing with KERS to 1.13 MJ per km. Downsizing the engine to 1.2 liters as permitted by the torque assistance by KERS, the fuel consumption is further reduced to 3.04 liters per 100 km, corresponding to 79.2 g of CO2 per km and 1.09 MJ per km of fuel energy. These CO2 and fuel usage values are 11% and 13% better than those of today’s highest fuel economy hybrid electric vehicle. The car equipped with a 1.6 liter Turbo Direct Injection Jet Ignition (TDI-JI) H2ICE engine finally consumes 8.3 g per km of fuel, corresponding to only 0.99 MJ per km of fuel energy

Improvements of truck fuel economy using mechanical regenerative braking

Improvements of truck fuel economy are being considered using a flywheel energy storage system concept. This system reduces the amount of mechanical energy needed by the thermal engine by recovering the vehicle kinetic energy during braking and then assisting torque requirements. The mechanical system has an overall efficiency over a full regenerative cycle of about 70%, about twice the efficiency of battery-based hybrids rated at about 36%. The technology may improve the vehicle fuel economy and hence reduced CO2 emissions by more than 30% over driving cycles characterized by: frequent engine start/stop, vehicle acceleration, brief cruising, deceleration and stop. The paper uses engine and vehicle simulations to compute: first the fuel benefits of the technology applied to passenger cars, then the extension of the technology to deal with heavy duty vehicles

Modelling of engine and vehicle for a compact car with a flywheel based kinetic energy recovery systems and a high efficiency small diesel engine

Recovery of kinetic energy during driving cycles is the most effective option to improve fuel economy and reduce green house gas (GHG) emissions. Flywheel kinetic energy recovery systems (KERS) may boost this efficiency up to values of about 70%. An engine and vehicle model is developed to simulate the fuel economy of a compact car equipped with a TDI Diesel engine and a KERS. Introduction of KERS reduces the fuel used by the 1.6L TDI engine to 3.16 liters per 100 km, corresponding to 82.4 g of CO2 per km. Downsizing the engine to 1.2 liters as permitted by the torque assistance by KERS, further reduces the fuel consumption to 3.04 liters per 100 km, corresponding to 79.2 g of CO2 per km. These CO2 values are 11% better than those of today’s most fuel efficient hybrid electric vehicle

Use of variable valve actuation to control the load in a direct injection, turbocharged, spark-ignition engine

Downsizing and Turbo Charging (TC) and Direct Injection (DI) may be combined with Variable Valve Actuation (VVA) to better deal with the challenges of fuel economy enhancement. VVA may control the load without throttle; control the valve directly and quickly; optimize combustion, produce large volumetric efficiency. Benefits lower fuel consumption, lower emissions and better performance and fun to drive. The paper presents an engine model of a 1.6 litre TDI VVA engine specifically designed to run pure ethanol, with computed engine maps for brake specific fuel consumption and efficiency. The paper also presents driving cycle results obtained with a vehicle model for a passenger car powered by this engine and a traditional naturally aspirated gasoline engine. Preliminary results of the VVA system coupled with downsizing, turbo charging and Direct Injection permits significant driving cycle fuel economies