Search Results

The Single Cylinder Research Engine (SCRE) at the Institute of Internal Combustion Engines and Powertrain Systems is equipped with a variable valve train that allows to switch between regular intake valve lift and early intake valve closing (Miller). On the exhaust side, a secondary valve lift on each valve is possible with adjustable back pressure and thus the possibility of realising internal EGR. In combination with alternative fuels, even if they are Drop-In capable as HVO, properties differ and can influence the emission and efficiency behaviour. The investigations of this paper are focusing on regenerative Drop-In fuel (HVO), fossil fuel (B7), and an oxygenate (OME), that needs adaptions at the engine control unit, but offers further emission potential. By commissioning a 2-stage boost system, it is possible to fully equalize the air mass in Miller mode compared to the normal valve lift.

Previous studies have shown that dosing AdBlue into the exhaust system of diesel engines to reduce nitrogen oxides can lead to an increase in the number of particles (PN). In addition to the influencing factors of exhaust gas temperature, exhaust gas mass flow and dosing quantity, the dosed medium itself (AdBlue) is not considered as a possible influence due to its regulation in ISO standard 22241. However, as the standard specifies limit value ranges for the individual regulated properties and components for newly sold AdBlue, in reality there is still some margin in the composition. This paper investigates the particle number increase due to AdBlue dosing using several CPCs. The increase in PN is determined by measuring the number of particles after DPF and thus directly before dosing as well as tailpipe. Several AdBlue products from different sources and countries are measured and their composition is also analyzed with regard to the limit values regulated in the standard.

Global efforts to reduce anthropogenic carbon dioxide (CO2) emissions require innovative measures in the field of vehicle drives to present solutions in all areas of the transportation sector in the future. Synthetic fuels, that can be used in conventional combustion engines, show promising potentials. An increasing amount of synthetic fuels will be found in the off-highway sector, which is characterized by a high power and work density. The properties of synthetic fuels can differ depending on their chemical structure. In particular, the calorific value (LHV) and the stoichiometric air-fuel-ratio (AFRst) have a direct influence on the performance and emission characteristics of an engine. In addition to providing optimal fuel-specific engine operation, fuel detection can ensure that the engine is only operated with regenerative energy carriers in future.

This study shows the newest results of a near-series pre-turbo-catalyst (PTC) system reaching lowest emissions for electrified diesel passenger cars to address future emission legislation. The PTC system is developed using a state-of-the-art tool chain containing 1D & 3D simulation approaches and testing near-series exhaust gas aftertreatment systems under real-driving boundary conditions. The innovative concept of a selective catalytic reduction (SCR) PTC and a PTC bypass path solve the challenge of a thermal handshake between PTC and underfloor SCR System as well as the challenge of a particular filter regeneration. The development of adaptive PTC bypass path operation strategies based on exhaust gas and catalyst conditions enables lowest NOx and NH3. Using this concept, zero-impact NOx emissions, that don’t impact cities air quality, can be reached in a wide range of operating scenarios while sustaining full drivability and highest efficiency.

Even under consideration of the increasing dynamics of measures to reduce CO2 in the transport sector and the resulting, now visible changes in the development and registration of new passenger cars (electrification), it is anticipated that vehicle drives containing an internal combustion engine will continue to have significant market shares in the medium to long term. It is assumed that a significant proportion of these cars will be hybrid vehicles in the future. As a result, in order to implement future requirements for improved air pollution control (Post EU6/Zero Impact) and CO2 reduction, consideration of these aspects must be an integral part of the application and of development activities in general. At TU Darmstadt, a consistent method for the development of powertrains with regard to their relevant real-world driving emissions - the Most Relevant Testing Procedure (MRTP), was established.

To meet the targets of the European Green Deal, CO2 emissions in the transport sector must be eliminated by 2050. To achieve these goals, it is not enough just to increase the powertrain efficiency. Regeneratively produced synthetic fuels offer the opportunity to be part of the solution to these challenges, due to their high energy density and wide range of applications. One representative of synthetic diesel fuels is oxymethylene ether (OME), which, in addition to its potential regenerative production process, is characterized by an almost soot-free combustion. Previous studies have demonstrated the feasibility of OME operation in a series engine. However, due to the limited amount of fuel that can be injected into the combustion chamber by series components, the potential in terms of efficiency could not be exploited.

To comply with the ambitious CO2 targets of the European Union, greenhouse gas emissions from the transport sector should be eliminated by 2050. Incremental powertrain improvement and electrification are only a part of the solution and need to be supplemented by carbon-neutral fuels. Due to the high technology readiness level, biofuels offer a short-term decarbonization measure. The high process energy demand for transesterification or hydrotreating however, hinders the well-to-wheel CO2 reduction potential of current market biodiesels. An often-raised, economically and energetically feasible alternative is to use unprocessed oils with viscosity and cold-properties improvers instead. The present work investigates the suitability of one such biofuel (PlantanolTM) for advanced common rail engines operating in a partially premixed compression ignition mode. Preliminary investigations are carried out on a Euro VIb light-duty car engine.

The “Two-Drive-Transmission with Range-Extender” (called DE-REX) is an innovative hybrid powertrain concept using two electric motors and an internal combustion engine. The two electric motors are permanent magnet synchronous motors with a maximum power of 48 kW each. As combustion engine a 3 cylinder, turbocharged engine with a power of 65 kW is used. The aggregates are coupled to a transmission whose layout is characterized by consisting of two parallel 2-speed sub-transmissions. This layout offers a high flexibility and enables both parallel and series hybrid driving. The hybrid control unit (HCU) has to select the optimal driving mode and power distribution between the aggregates in regard to in some extend competing objectives like efficiency, emissions or driving comfort. In particular, the operation of the internal combustion engine with only two gear ratios is challenging.

Due to the new CO2 targets for vehicles, electrification of powertrains and operation strategies for electrified powertrains have drawn more attention. This article presents a predictive multi-objective operation strategy for hybrid electric vehicles (HEVs), which simultaneously minimizes the fuel consumption and the cycle aging of traction batteries. This proposed strategy shows better performance by using predictive information and high robustness to inaccuracy of predictive information. In this work, the benefits of the developed operation strategies are demonstrated in a strong hybrid electric vehicle (sHEV) with P2-configuration. For the cycle aging of a lithium-ion battery, an empirical model is built up with Gaussian processes based on experimental data.

Recently, the European Union has adopted a new regulation on Real-Driving-Emissions (RDE) and also China is considering RDE implementation into new China 6 legislation. The new RDE regulation is focused on measuring nitrogen oxides (NOx) and particulate number (PN) emissions of both light-duty gasoline and diesel vehicles under real world conditions. A supplemental RDE test procedure was developed for European type approval, which includes on-road testing with cars equipped with portable emission measurement systems (PEMS). This new regulation will significantly affect the engine calibrations and the exhaust gas aftertreatment. In this study the impact of the new RDE regulation on two recent EU 6b certified turbocharged direct injected gasoline vehicles has been investigated. A comparison of several chassis dyno drive cycles with two new defined on-road RDE cycles was performed.

Powertrain systems exploiting information from vehicle connectivity have widened the system boundary resulting in additional degrees-of-freedom for predictive trajectory planning. Heuristic methods based on component characteristics are currently widely used for Energy Management (EM) functionality of hybridized powertrains. Despite their better usability, increased calibration effort and sensitivity to synthetic calibration scenarios are drawbacks of such control methods. Availability of predictive data, better computing power and challenges posed by various scenarios in real driving, have led to interest in online-optimizing EM functionality. Equivalent Consumption Minimization Strategy (ECMS) approaches based on Indirect optimal control /Pontryagin Minimum principle have difficulty in handling inequality state constraints. Extensions of ECMS make use of modifications to the equivalence factor/co-state, based on prediction of driving conditions.

Thanks to direct injection and turbocharging, downsizing technology has found widespread acceptance in series production engines. Fuel consumption for NEDC and also real world driving conditions can be reduced significantly depending on the extend of downsizing. For future applications 3 cylinder gasoline engines have already been announced for up to 140 kW by premium OEMs. Recent developments focus on well-adjusted downsizing rates taking into account merits and demerits of conventional charging technologies. One of the biggest challenge in the development process is to meet the customer's demands regarding vehicle driveability for downsized turbocharged gasoline engines for real world driving conditions. Scavenging has proven to be very beneficial to meet the required vehicle responsiveness. Pressure charged production engines are now delivering more than 200 % of the BMEP that was typical for naturally aspirated engines a few years ago.

The exploitation of full load capabilities of DI gasoline engines requires at least the same degree of effort as in MPFI engine development. An optics based sensor and sensing technique is presented, which together with conventional pressure indicating provides identification of self ignition centers as the engine is operated under knock or borderline knock conditions. The knock location sensor is configured as a spark plug providing the relevant spark plug properties together with the multichannel optical access into the upper part of the combustion chamber. Functionality and sensitivity of this sensing technique are demonstrated and results for combustion system development are shown.