Fig­ure: Mea­sure­ments on the aux­il­iary units

Mea­sure­ments on the aux­il­iary units

Prob­lem: Slip­page, belt vibra­tions, pre­ma­ture wear of the belt dri­ve com­po­nents

Goal: Pre­cise design of the aux­il­iary units

Aux­il­iary dri­ves such as the pow­er steer­ing pump or the air-con­di­tion­ing com­pres­sor, which reg­u­lates the tem­per­a­ture in the vehi­cle, pro­vide a high lev­el of dri­ving com­fort. To pre­vent dam­age, cor­rect belt ten­sion must be ensured in the aux­il­iary dri­ves at all times. If the ten­sion is too low, this leads to slip­page and belt vibra­tions and thus to pre­ma­ture wear of the belt dri­ve com­po­nents.

The func­tion­al tests on aux­il­iary dri­ves (FEAD) and belt-starter-gen­er­a­tor dri­ves (BAS) com­prise the mea­sure­ment and eval­u­a­tion of the slip and dynam­ic behav­ior of the entire belt dri­ve sys­tem.
In fig­ure above, the belt forces, ten­sion­er move­ments and belt vibra­tions are impor­tant mea­sured vari­ables in addi­tion to the high-res­o­lu­tion mea­sure­ment of the rota­tion­al angle posi­tion of the crank­shaft and all oth­er belt pul­leys. In addi­tion, the oper­at­ing state of the engine and the load con­di­tions of the aux­il­iary units as well as the cur­rent torque of the BAS gen­er­a­tor have a sig­nif­i­cant influ­ence on the dri­ve behav­ior. The eval­u­a­tion is per­formed in time and spec­tral domain.

In hybrid dri­ves, the state of charge of the bat­tery plays a sig­nif­i­cant role. Here, most of the vari­ables are avail­able with suf­fi­cient res­o­lu­tion on the CAN BUS and can be record­ed using the ROTEC CAN BUS board.
In BAS sys­tems, the start­ing and stop­ping process­es of the engine as well as the switch­ing of the starter gen­er­a­tor between engine and gen­er­a­tor oper­a­tion (recu­per­a­tion) rep­re­sent one of the most dif­fi­cult dynam­ic states, which is why sen­sor tech­nol­o­gy with detec­tion of the direc­tion of rota­tion is required to record the cor­rect speed ratios. For this task ROTEC pro­vides appro­pri­ate sen­sor solu­tions such as encoder adap­ta­tion mod­ules or quadru­ple sen­sors.

The record­ed mea­sured val­ues are eval­u­at­ed in the time and spec­tral domain.

Fur­ther­more ROTEC ENGI­NEER­ING pro­vides you with sup­port and tech­ni­cal engi­neer­ing know-how for prob­lems relat­ed to vibra­tion analy­sis of engines, trans­mis­sions and dri­ve trains. With our know-how, we make a valu­able con­tri­bu­tion to your prod­uct in the areas of tim­ing gear val­i­da­tion, valve train opti­miza­tion, clutch design, trans­mis­sion errors (TE), trans­mis­sion opti­miza­tion, oil sup­ply opti­miza­tion, pow­er­train mea­sure­ment and opti­miza­tion, cur­rent and volt­age analy­sis, and the appli­ca­tion of mea­sure­ment tech­nol­o­gy.

Time Domain

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  • Belt loads
  • Bear­ing forces
  • Ten­sion­er pre­load and damp­ing forces
  • Force vec­tor cal­cu­la­tion depend­ing on the ten­sion­er posi­tion
  • Slip behav­ior in the over­all trans­mis­sion
  • Start and stop behav­ior
  • Speed gra­di­ent and peak torque eval­u­a­tions

Spec­tral Domain

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  • Analy­sis of dynam­ic exci­ta­tions
  • Ver­i­fi­ca­tion of vibra­tion dampers and cou­pling sys­tems
  • Res­o­nance behav­ior of the over­all sys­tem
  • Change of nat­ur­al fre­quen­cies over ambi­ent con­di­tion
  • Dynam­ic peak loads