Angular Position Detection Device in a Hybrid Vehicle

Abstract

An angular position detection device in a hybrid vehicle includes a crankshaft sensor for detecting an absolute internal combustion engine angular position with respect to a defined position mark, an electric machine, a rotor position sensor for detecting a relative electric machine angular position based on a reference point, in particular a reference pole comprising a plurality of identical rotor poles, and an electronic control unit. The control unit is configured such that the absolute internal combustion engine angular position and the relative electric machine angular position are detected when the internal combustion engine is stationary and the electric machine is stationary, and a mechanical angular reference of the internal combustion engine with respect to the electric machine is determined, on the basis of these angular positions, as an angle difference between the position mark and an initial reference point.

Claims

1.-10. (canceled)

11. An angular position detection device in a hybrid vehicle with an internal combustion engine, the angular position detection device comprising: a crankshaft sensor for detecting an absolute internal combustion engine angular position with respect to a defined position mark, an electric machine, a rotor position sensor for detecting a relative electric machine angular position in relation to a reference point, and at least one electronic control unit, wherein: an absolute angular position of the internal combustion engine and the relative angular position of the electric machine are detected when the internal combustion engine is stationary or at least only rotating slowly and the electric machine is stationary or at least or only rotating slowly, and based on the absolute angular position of the internal combustion engine and the selective angular position of the electric machine, a mechanical angular reference of the internal combustion engine to the electric machine is determined as an angular difference between the position mark and an initial reference point and is stored.

12. The angular position detection device according to claim 11, wherein the reference point is a reference pole consisting of several rotor poles of the same type.

13. The angular position detection device according to claim 11, wherein at a first stop of the internal combustion engine and the electric machine, for purposes of a learning function, a mechanical initial angular reference is determined in relation to the initial reference point.

14. The angular position detection device according to claim 13, wherein the reference point is an initial reference pole.

15. The angular position detection device according to claim 14, wherein at each subsequent start after a first start of the internal combustion engine and the electric machine, a geometrically first detected pole is selected as a new reference pole on an assumption that the geometrically first detected pole is the initial reference pole.

16. The angular position detection device according to claim 15, wherein: at each subsequent start and/or stop of the internal combustion engine and the electric machine after the learning function, a current mechanical angular reference is adjusted, a first adjustment component represents pole shifts between the initial reference point and the new reference pole, and a second adjustment component represents a newly calculated mechanical angular reference, taking into account the first adjustment component.

17. The angular position detection device according to claim 15, wherein: at each subsequent start and/or stop of the internal combustion engine and the electric machine after the learning function, a current mechanical angular reference is adjusted, a first adjustment component represents pole shifts between the initial reference point and the new reference pole, and a second adjustment component represents a mean value between the current mechanical angular reference and a newly calculated mechanical angular reference, taking into account the first adjustment component.

18. The angular position detection device according to claim 11, wherein an adjustment function is carried out at each stop of the internal combustion engine and the electric machine after a learning function.

19. The angular position detection device according to claim 11, wherein an adjustment function in the internal combustion engine control unit is carried out immediately after a start of the internal combustion engine by temporarily storing the relative angular position of the electric machine when the electric machine is stationary before the start of the internal combustion engine, counting the pulses of the crankshaft sensor until the defined position mark is detected, and recalculating the internal combustion engine angular position before the engine start based on a number of pulses counted, in order to calculate the mechanical angular reference between the electric machine and the internal combustion engine before a stop based on the recalculated internal combustion engine angular position when the internal combustion engine is stationary and on a temporarily stored electric machine angular reference when the electric machine is stationary.

20. A hybrid vehicle comprising the angular position detection device according to claim 11.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] FIG. 1 shows schematically essential components and sizes of the entire engine-transmission composite system.

[0036] FIG. 2 shows a schematic representation of the mode of operation of the device according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

[0037] In FIG. 1, an engine-transmission composite system MGV in a hybrid vehicle is shown with an internal combustion engine VM, with an electric machine EM, with an electric machine control unit EMS, with an internal combustion engine control unit VMS and with a communication bus B between the electric machine control unit EMS and the internal combustion engine control unit VMS. The engine-transmission composite system MGV is housed in an engine-transmission composite system housing MGV-G, which can also contain a dual-mass flywheel ZMS, a torque converter clutch WK and a torque converter WD for an automatic transmission (transmission input torque MGET). In particular, the internal combustion engine VM and the electric machine EM are connected to the engine-transmission composite system housing MGV-G in a vibration-relevant manner. The electric machine EM can produce a total torque consisting of a basic drive torque and a torque reducing the vibration excitations of the engine-transmission composite system. For this purpose, the knowledge of the mechanical angular reference between the internal combustion engine and the electric machine is necessary, the calculation of which is discussed below and explained in more detail on the basis of FIG. 2.

[0038] FIG. 2 shows in more detail how, by way of the appropriate design or programming of the electric machine control unit EMS and/or the internal combustion engine control unit, the mechanical angular reference of the internal combustion engine VM with respect to the electric machine EM, i.e. the initial mechanical angular reference W_RP of the learning function or the averaged mechanical angular reference W_RP_mittel of the adjustment function, can be determined, in particular when the internal combustion engine VM is stationary and the electric machine EM is stationary:

[0039] FIG. 1 and FIG. 2 show schematically a first angular position detection function 1 for the detection of an absolute internal combustion engine angular position KW with respect to the ignition TDC ZOT as a defined position mark and a second angular position detection function 2 for the detection of a relative electric machine angular position RW with respect to a reference pointhere preferably to a reference pole, either the initial reference pole RP or a later new reference pole RP. The initial reference pole RP is a reference pole detected for the first time during a learning function after a first start. A reference pole is basically a first pole of several similar rotor poles, in this case 10 poles, selected by the electric machine control unit EMS.

[0040] According to embodiments of the invention, when the internal combustion engine VM is stationary and the electric machine EM is stationary, the absolute angular position KW_stop of the internal combustion engine is detected by the internal combustion engine control unit VMS and the relative electric machine angular position RW_stop is detected by the electric machine control unit EMS. The control units EMS and VMS exchange data cyclically via the bus B. In at least one of the control units VMS and EMS, based on these angular positions RW_stop and KW_stop a mechanical angular reference W_RP or W_RP_mittel of the internal combustion engine VM with respect to the electric machine EM is determined as an angular difference between the position mark ZOT and the initial reference pole RP and is stored.

[0041] Preferably, the mechanical initial angular reference W_RP is determined at a first start or stop of the internal combustion engine VM and the electric machine EM for the purposes of a learning function related to the initial reference pole RP.

[0042] In a development of the invention, at each subsequent start after a first start of the internal combustion engine VM, in the electric machine EM the reference pole RP, which is stored in a non-volatile form (for example in an NVRAM), is selected, but in the event of a fault, it may not be the actual reference pole, but another pole, which is then geometrically recognized as the first pole. This pole is referred to as the new reference pole RP.

[0043] Explanation: in the electric machine control unit, the last reference pole is stored when the control unit falls asleep. When the control unit wakes up, the stored reference pole is read out and the calculation continues from this pole, which however can actually be a new reference pole RP. As long as the crankshaft-electric machine composite system has not continued to rotate during sleep, no pole shift will occur. If the readout of the NVRAM value does not work or the crankshaft or the electric machine has continued to turn, the electric machine control unit assumes the initial reference pole RP, but in reality it is the new reference pole RP which is corrected by the adjustment function according to embodiments of the invention by way of recognized pole shifts.

[0044] A learning function is followed by an adjustment function, wherein at each subsequent start and/or stop of the internal combustion engine VM and the electric machine EM the current mechanical angular reference W_RP or W_RP_mittel(alt) is adjusted. Preferably, a first and a second adjustment component are calculated in the internal combustion engine control unit VMS. A first adjustment component W_PS represents the pole shifts PS, for example in the form of the number of pole shifts, between the initial reference pole RP and the new reference pole RP. Furthermore, a second adjustment component W_RP_mittel(neu) represents the mean value between the current mechanical angular reference W_RPi (:=W_RP or W_RP_mittel(alt)) and the newly calculated mechanical angular reference W_RPi+1=W_RPW_PS. Here, W_RP is the initially wrong determined angle difference between ZOT and the new reference pole RP if it is not equal to the initial reference pole.

[0045] The adjustment function can be carried out at each stop of the internal combustion engine VM and the electric machine EM after a learning function.

[0046] In an advantageous embodiment of the invention, however, the adjustment function can also be carried out in the internal combustion engine control unit VMS immediately after a start of the internal combustion engine VM by temporarily storing, before the start of the internal combustion engine VM, the electromechanical electric machine angular position RW_stop when the electric machine EM is stationary, counting the pulses of the crankshaft sensor until the defined position mark ZOT is detected and, based on the counted number of pulses, recalculating the internal combustion engine angular position KW before the engine start. Based on this recalculated internal combustion engine angular position KW_stop with the internal combustion engine VM stationary and on the temporarily stored electromechanical electric machine angular position RW_stop with the electric machine EM stationary, the mechanical angular reference W_RP or W_RP_mittel can be calculated before a stop.