Hybrid powertrains with dedicated internal combustion engines are the perfect basis for future global mobility demands

Abstract

In order to still reach the 1.5°C or at least 2°C target, a rapid and significant reduction in the CO2 contribution of all sectors must be achieved. The transport sector in particular has a duty here, as it contributes around 20% to global CO2 emissions and this figure has increased rather than decreased in recent decades as a result of a drastic increase in passenger and freight kilometers.The automotive industry is already making a strong contribution to this through an increasing number of electric vehicles in new vehicle registrations. However, this will not be sufficient, because on the one hand the increase of vehicles in the market is due to several reasons happening not fast enough, and on the other hand the electricity available for the vehicles will not be generated fast enough from fully renewable electricity sources.So as long the supply of regenerative electricity is not sufficient, and as long there are above all many places and applications in the world where a switch to pure electromobility will not be possible in the short and medium term, other highly efficient drive systems will have to be offered in parallel. Highly efficient because only in this way can the valuable energy, from whatever source, be used extremely sparingly.In order to evaluate to what extent hybrid powertrains can contribute to a reduction of the CO2 pollution of the transport sector, this paper deals with the virtual investigation of different hybrid powertrains. In a first step, it is deduced why hybrid powertrains are fundamentally interesting and what potential they have if they are consistently optimized for maximum efficiency. It becomes clear that there is considerable potential in them and that, with consistent further development, they can actually come very close to the future CO2 fleet limits. To achieve this, however, all powertrain components must be optimized. For this reason, a further section presents technologies, such as Pre-Chamber Spark Plugs (PCSP) and technology packages for internal combustion engines that have been optimized specifically for use in hybrid powertrains and achieve Break Thermal Efficiency (BTE) levels of more than 45%.Finally, in the last major chapter, various hybrid topologies are combined with the presented high-efficiency internal combustion engines from chapter 2 and are evaluated in a large simulation study. With the aim to achieve a maximum overall powertrain efficiency under real world driving conditions a combination of a parallel and a serial topology seems most promising.Due to their efficiency and conservation of energy resources, hybrid powertrains have the potential to meet a significant share of future global mobility needs.