Along with increased oil prices and rising environmental issues, a demand for alternatives to combustion engine driven hydraulic applications has risen. In the field of mobile hydraulics, the hydraulic applications have traditionally been driven by the combustion engine of the vehicle on which they are mounted. By instead using a battery driven power pack the hydraulic application is able to operate without the engine running, saving fuel costs and reducing sound levels. In this thesis, the concept of using an electric-hydraulic power pack with a variable-speed electric motor and a fixed-displacement hydraulic pump to provide power to a truck-mounted loader crane is investigated. This concept is compared to an electric-hydraulic system imitating the conventional combustion engine system by using a fixed-speed electric motor connected to a variable-displacement pump. The use of a variable speed motor where the speed can be controlled electrically by a control unit creates possibilities of using different control strategies to improve the efficiency and responsiveness of the application. The efficiencies of the two electric-hydraulic systems are compared by constructing a physical test rig and performing measurements in a test lab. The tests have shown an increased efficiency of about 20 \% when using the variable speed configuration. Three different control strategies are also investigated and tested on a simulated model. The simulations show that very good responsiveness and robustness can be achieved by using a hydraulic flow feed forward controller with a complementary pressure feedback controller. Furthermore, by controlling the hydraulic flow to the heaviest of the crane loads entirely with the flow from the hydraulic pump, the hydraulic pressure can be reduced and energy efficiency increased.

Denna kandidatuppsats är en studie av miljöprestandan hos   en lastbilskran satt i relation till användning av en mobilkran.   Miljöprestandan hos lastbilskranen studeras och jämförs med mobilkranens   givet ett visst nyttjandescenario. Miljöprestandan mäts i miljöparametrarna:   klimatpåverkan, energiförbrukning, energieffektivitet samt partikelutsläpp.   Realistiska och mätbara nyttjandescenarier har utarbetats utifrån studiebesök   och intervjuer med Vemservice, Jämtlands Mobilkranar och Curt Sillström   Åkeri. Kandidatuppsatsen är skriven som en del i den miljöstudie som ingår i   utvecklingsprojektet Forskning och utveckling av lastbilars   centralram för minskad miljöpåverkan vid tung transport. Projektet   drivs av Vemservice (Vemdalsservice AB) och syftar till att utveckla   centralramen på en lastbilskran genom att öka dess lyftkapacitet. Projektets   mål är att ersätta mobilkranar med lastbilskranar i en högre utsträckning än   vad som görs idag. I projektet deltar även teknikkonsultföretaget DRIV   Innovation, materialoptimeringstjänsten SSAB Shape samt Mittuniversitetet. En lastbilskran är en lastbil med en kran påmonterad på   flaket, med plats på flaket för att transportera gods. Lyftförmågan hos en   lastbilskran beror både av kranens styrka och själva lastbilens vrid- och böjhållfasthet.   I denna studie har en lastbilskran från Curt Sillströms Åkeri studerats.   Lastbilskranens främsta användningsområden är vid nybyggnationer av   bostäder, flytt av containrar och bodar på arbetsplatser samt vid flytt av   tunga föremål in och ut ur byggnader. Mobilkran kallas det   arbetsfordon som har en lyftkran med svängarm monterad på fordonet, den används inte för transport av gods.   Mobilkranen i denna studie tillhör Jämtlands Mobilkranar och används främst i   lyftarbeten såsom byggande av bostäder och arbeten vid vattenkraftverk. Resultatet   av den studerade miljöprestandan baseras på tre specifika nyttjandescenarior.   Nyttjandescenarierna innefattade att transportera och lyfta en given mängd   gods en given sträcka och tid. Lastbilskranen har högre miljöprestanda än   mobilkranen vid jämförelse i de tre scenarierna, dvs. lägre utsläpp och   mindre energiförbrukning. Den minsta skillnaden i miljöprestanda uppstår när   enbart lyftarbete utförs, då lastbilskranens fulla funktion inte nyttjas då   den ej transporterar något gods. Det troligtvis mest typiska   nyttjandescenariot är att gods både ska transporteras och lyftas. I detta   fall har lastbilskranen flera fördelar tack vare att dess fulla funktion   utnyttjas. / This bachelor thesis is a study of the environmental performance of a loader crane in relationship to the usage of a mobile crane. The environmental performance of the loader crane is studied and compared to the mobile cranes performance given a set of specific user scenarios. The environmental performance is measured using the following environmental parameters:climate impact, energy consumption, energy efficiency and particle emissions. Realistic and measurable user scenarios were prepared using information from visits and interviews with Vemservice, Jämtlands Mobilkranar and Curt Sillström Åkeri. The thesis is written as a part of the environmental study that is included in the developmental project “Forskning och utveckling av lastbilars centralram för minskad miljöpåverkan vid tung transport”. The project is managed by Vemservice (Vemdalsservice AB) and the purpose of the project is to develop the frame on a loader crane by increasing the capacity for lifting. The goal of the project is to replace mobile cranes with loader cranes to a higher degree than what is currently the case. The projects participants are also made up by the technology consulting DRIV Innovation, SSAB Shape and also Mid Sweden University. A loader crane is a truck with a crane mounted on its flatbed and also room on the flatbed for the transport of goods. The lifting capabilities of a loader crane is dependent on the strength of the crane and the rigidity of the frame of the truck itself. In this thesis, a loader crane from Curt Sillström Åkeri AB is studied. The main usage of the loader crane in this study is in construction, the moving of work site sheds and in the moving of heavy objects in and out of houses. A mobile crane is a work vehicle with a crane and swing arm mounted on the back of the vehicle. The mobile crane in this study belongs to Jämtlands Mobilkranar and is primary used for heavy lifting in construction and work at a hydro power plant. As opposed to the loader crane, the mobile crane is not used for the transport of goods. The resulting environmental performance was based on three specific user scenarios. The user scenarios consisted of lifting and transporting a given amount of goods for a specified distance and time. When a comparison is made between the loader crane and mobile crane for total emissions and energy consumption in each user scenario, the loader crane has a larger environmental performance. The smallest difference in environmental performance arises when lifting is the only work being done, due to the fact that the full capacity of the loader crane is not utilized since it is not used to transport goods. Likely the most typical user scenario consists of goods being both transported and lifted. In this case the loader crane has a number of advantages because its full capacity is being utilized. / <p>2018-02-01</p>

Imagine a system with a pump driven by a speed-controlled electric motor. What and how much can be gained by using a pump with discretely variable displacement instead of a conventional fixed pump in such a system? This question is the focus in this paper, in which a simulation study based on a drive cycle for a loader crane is presented. The results indicate that the system efficiency from inverter input to pump output can increase by a few percentages. This might be considered small in relation to the increasing complexity that comes with discrete displacement. However, the results also show that a system with discrete displacement substantially reduces torque and cooling requirements on the electric motor. The required maximum torque can be reduced by 30 to 50 % and the motor can generate up to 40 % less heat since it can work in more efficient conditions. These potential benefits will be obtained with only a few discrete displacement settings available.