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The use of reciprocating internal combustion engines (ICE) dominates the sector of the on-road transportation, both for passengers and freight. CO2 reduction is the present technological driver, considering the major worldwide greenhouse reduction targets committed by most governments in the western world. In the near future (2020) these targets will require a significant reduction with respect to today’s goals, reinforcing the importance of reducing fuel consumption. In ICEs more than one third of the fuel energy used is rejected into the environment as thermal waste through exhaust gases. Therefore, a greater fuel economy could be achieved if this energy is recovered and converted into useful mechanical or electrical power on board. For long haul vehicles, which run for hundreds of thousands of miles per year at relatively steady conditions, this recovery appears especially worthy of attention.

Internal combustion engines are actually one of the most important source of pollutants and greenhouse gases emissions. In particular, on-the-road transportation sector has taken the environmental challenge of reducing greenhouse gases emissions and worldwide governments set up regulations in order to limit them and fuel consumption from vehicles. Among the several technologies under development, an ORC unit bottomed exhaust gas seems to be very promising, but it still has several complications when it is applied on board of a vehicle (weight, encumbrances, backpressure effect on the engine, safety, reliability). In this paper, a comprehensive mathematical model of an ORC unit bottomed a heavy duty engine, used for commercial vehicle, has been developed.

In the last years, the design of internal combustion engines (ICE) has evolved significantly, mainly because of the changing demand of mobility, the need to limit the pollution produced by vehicles, and recently, the opportunity to reduce emissions of climate-altering gases. Among the more interesting technologies, those connected to a revision of the engine cooling, as well as, in general, of the thermal needs on board vehicle (oil cooling, intercooling of the turbocharging air, EGR cooling, cabin conditioning...) appear very promising, also because characterized by a lower cost increase per unit of CO₂ saved. In this paper, the Authors present a mathematical model of an internal combustion engine physically consistent that appraises the performances of conventional and unconventional engine cooling systems and the integration of vehicle thermal needs.

The growing interest on environmental issues related to vehicles is pushing up the research on reciprocating internal combustion engines which seems to be endless and able to insure to combustion engines a long future. Euro standards imposed a significant reduction of pollutant emissions and were the stimulus to favor the conception of technologies which represented real breakthroughs; the recent directives on greenhouse gases emissions further reinforced the concept of reducing fuel consumption and, consequently, carbon dioxide emissions. So, new technological efforts have to be made on internal combustion engines in order to achieve this additional target: several technological options are already available or under studying, but only a few of these are suitable, in particular, in terms of costs attendance per unit of CO2 saved. Among these technologies, a revision of engine cooling system seems to have good potentiality.

In the perspective of fuel saving and emissions reduction, engine oil thermal management has not yet received the attention it deserves. Lubricating oil, in fact, should be the focus of a specific warmup action: the expected benefits is on friction reduction – mechanical efficiency improvement – but also on a positive interaction with the cooling fluid thermal dynamics. The lower thermal capacity of the circulating oil (with respect to the cooling fluid) and the instantaneous reduction of the viscosity due to temperature increase produces a faster engine overall efficiency benefit: this invites to focus specific actions on its thermal management in the direction of speeding up the temperature rise during a cold engine starting.

The dynamic performances of the cooling circuit have a great impact on ICE efficiency and CO2 emissions. Engine thermal management is among the most promising technologies able to offer a sensible reduction in terms of engine fuel consumption and CO2 emission. These aspects are widely treated in literature and many technologies are already on the market or ready to be used. A reduced attention in literature, has been done on the pump performances during the real operating conditions. Homologation cycles try to reproduce these conditions. In light duty vehicles these cycles consist in accelerating and decelerating the engine following a specified velocity-time sequence. According to this procedure, the propulsion power requested by the vehicle is low, and the power absorbed by the auxiliaries became significant. The pump of the cooling fluid is the most important component among the auxiliaries.

Fuel consumption reduction and CO2 emissions saving are the present drivers of the technological innovation in Internal Combustion Engines for the transportation sector. Among the numerous technologies which ensure such benefits, the role of the cooling pump has been recognized, mainly referred to the possibility to improve engine performances during warm up. During engine homologation, an additional benefit on the fuel consumption can be also reached reducing the energy demand of the pump. In fact, during the cycle, propulsion power requested by the vehicle is low and the importance of the energy absorbed by the pump became significant, since the pump operates far from its maximum efficiency.

Within automotive sector, there are several high-performance applications, like, for instance, those referred to racing and motorsport, where cooling needs are usually fulfilled by simple circuits with conventional low-efficiency pumps. The cooling needs in these applications are represented by low flow rates delivered (in the range of 10 - 50 L/min). The operating conditions of these small pumps are usually characterized by very high revolution speeds, which intrinsically cause low efficiency and critical intake phenomena (cavitation) if the design is not specifically optimized to address these concerns. Hence, in this paper a small-size pump operating in the racing sector has been designed using a model-based approach, built and tested having reached both high efficiency (aimed to 50%) and absence of intake operational problems (cavitation).

Reducing CO2 emissions in on-the-road transport is important to limit global warming and follow a green transition towards net zero Carbon by 2050. In a long-term scenario, electrification will be the future of transportation. However, in the mid-term, the priority should be given more strongly to other technological alternatives (e.g., decarbonization of the electrical energy and battery recharging time). In the short- to mid-term, the technological and environmental reinforcement of ICEs could participate in the effort of decarbonization, also matching the need to reduce harmful pollutant emissions, mainly during traveling in urban areas. Engine thermal management represents a viable solution considering its potential benefits and limited implementation costs compared to other technologies. A variable flow coolant pump actuated independently from the crankshaft represents the critical component of a thermal management system.

The need for even more efficient internal combustion engines in the road transportation sector is a mandatory step to reduce the related CO2 emissions. In fact, this sector impacts significantly on greenhouse gases worldwide, and the path toward hybrid and electric powertrains has just begun. In particular, in heavy-duty vehicles the full electrification of the powertrain is far to be considered as a really feasible alternative. So, internal combustion engines will still play a significant role in the near/medium future. Hence, technologies having a low cost to benefits (CO2 reduction) ratio will be favorably introduced in existing engines. Thermal management of engines is today a recognized area of research. Inside this area, the interest toward the lubricant oil has a great potential but not yet fully exploited. Engine oil is responsible of the mechanical efficiency of the engine which has a significant potential of improvement.