Power split Hydro-mechanical Variable Transmission (HVT) for off-highway application

Nowadays the needs to fulfill severe emission standards and to reduce the mobile machine operative costs have driven the off-highway industrial research towards new solutions able to increase the overall vehicle efficiency. Within this scenario, smart power split transmissions demonstrated to be a very attractive technology able to achieve the fuel consumption reduction targets, increasing the machine working cycle productivity. Compared to the standard technologies (such as Torque Converters - TC), the power split hydromechanical varible transmissin (HVT), designed and developed by Dana Rexroth Transmission Systems S.r.l. (DRTS), is able to fully decouple the engine to wheel behavior during the machine working cycle, with an higher efficiency than a pure hydrostatic transmission. Due to this fundamental characteristic, the HVT allows the engine to work next to the maximum efficiency point, consequently it is possible to downsize the engine to further increase the fuel saving. The analysis of the field test performed by an off-highway vehicle (Kalmar Cargotec DRG Gloria 450 reachstacker) equipped with a DRTS HVT has been shown along this paper; particular attention has been given to the cycle load spectra, the fuel consumption and the working cycle productivity through a comparison with standard TC technologies

Power split Hydro-mechanical Variable Transmission (HVT) for off-highway application

Nowadays the needs to fulfill severe emission standards and to reduce the mobile machine operative costs have driven the off-highway industrial research towards new solutions able to increase the overall vehicle efficiency. Within this scenario, smart power split transmissions demonstrated to be a very attractive technology able to achieve the fuel consumption reduction targets, increasing the machine working cycle productivity. Compared to the standard technologies (such as Torque Converters - TC), the power split hydromechanical varible transmissin (HVT), designed and developed by Dana Rexroth Transmission Systems S.r.l. (DRTS), is able to fully decouple the engine to wheel behavior during the machine working cycle, with an higher efficiency than a pure hydrostatic transmission. Due to this fundamental characteristic, the HVT allows the engine to work next to the maximum efficiency point, consequently it is possible to downsize the engine to further increase the fuel saving. The analysis of the field test performed by an off-highway vehicle (Kalmar Cargotec DRG Gloria 450 reachstacker) equipped with a DRTS HVT has been shown along this paper; particular attention has been given to the cycle load spectra, the fuel consumption and the working cycle productivity through a comparison with standard TC technologies

Power split Hydro-mechanical Variable Transmission (HVT) for off-highway application

Nowadays the needs to fulfill severe emission standards and to reduce the mobile machine operative costs have driven the off-highway industrial research towards new solutions able to increase the overall vehicle efficiency. Within this scenario, smart power split transmissions demonstrated to be a very attractive technology able to achieve the fuel consumption reduction targets, increasing the machine working cycle productivity. Compared to the standard technologies (such as Torque Converters - TC), the power split hydromechanical varible transmissin (HVT), designed and developed by Dana Rexroth Transmission Systems S.r.l. (DRTS), is able to fully decouple the engine to wheel behavior during the machine working cycle, with an higher efficiency than a pure hydrostatic transmission. Due to this fundamental characteristic, the HVT allows the engine to work next to the maximum efficiency point, consequently it is possible to downsize the engine to further increase the fuel saving. The analysis of the field test performed by an off-highway vehicle (Kalmar Cargotec DRG Gloria 450 reachstacker) equipped with a DRTS HVT has been shown along this paper; particular attention has been given to the cycle load spectra, the fuel consumption and the working cycle productivity through a comparison with standard TC technologies

An adaptive reset control scheme for valve current tracking in a power-split transmission system

International audienceIn power-split transmission systems developed by Dana-Rexroth Transmission Systems, a crucial role is played by the adjustable mechanical couplings performed by clutches operated by means of suitable electrovalves. We propose here a reset control scheme with adaptive feedforward action to perfectly track a known smooth reference for the current flowing in the valves. Formal properties of the scheme are first established and then a simplified approximated version is proposed for a simple implementation on the real-time control system. We report on simulation and experimental results both illustrating illustrate desirable responses. Simulations also confirm the theoretical results about asymptotic convergence of the estimates to the values of the unknown valve parameters

LMI-based non-overshooting pressure control design for a wet clutch

International audienceA Hydromechanical Variable Transmission is a device able to efficiently transmit non-constant mechanical torque from a source to a load. To suitably control this torque, Dana Rexroth has developed a hybrid transmission that combines a hydrostatic pathway and a mechanical one. The power transmitted along each pathway can be controlled by means of clutches. The torque and so the power transferred by each clutch depends on the oil pressure inside it. For this reason in this work we investigate a novel strategy for oil pressure control. First, we developed a simplified model for filled clutch systems and the related identification technique. Second, we developed a controller that ensures a fast rise time and a non-overshooting behavior. The controller synthesis relies on a convex Linear Matrix Inequalities formulation. The experimental tests show desirable rise time, overshoot and good robustness with respect to modeling errors and noise

Hybrid Nonovershooting Set-Point Pressure Regulation for a Wet Clutch

International audienceWe propose a control oriented Wiener model for wet-clutches in filled conditions and we discuss the associated identification technique. We design a novel hybrid controller, which ensures zero steady-state error and a fast non-overshooting response. We show that the controller parameters can be conveniently obtained by solving a set of linear matrix inequalities. Finally, we test the proposed control strategy on the hydromechanical variable transmission developed by Dana-Rexroth Transmission Systems. The experiments show good performance and robustness with respect to modeling errors and noise