Controller for Operating a Road-Coupled Hybrid Vehicle

Abstract

A control device is provided for operating a road-coupled hybrid vehicle, which is equipped with an electronic control unit, a first drive unit paired with a primary axle, and a second drive unit paired with a secondary axle. The control unit is designed to receive input variables including a specified sum target creep torque and a command to switch over from the single-axle operation to the two-axle operation with a specified all-wheel factor. The control unit sets a specified target torque for an internal combustion engine of the primary axle according to the all-wheel factor and detects the resulting actual coupling torque of the automatic transmission. If the functional module of the control unit ascertains a difference between the actual coupling torque and the sum target creep torque, the functional module specifies a corresponding target torque for an electric drive motor of the secondary axle to compensate for the difference.

Claims

1.-5. (canceled)

6. A control device for operation of a road-coupled hybrid vehicle with at least one electronic control unit, with a first drive unit associated with a primary axle and with a second drive unit associated with a secondary axle, wherein the drive unit of the primary axle has at least one internal combustion engine and an automated transmission and the drive unit of the secondary axle has at least one electric drive motor, and wherein the at least one control unit is configured to: receive a specified sum target creep torque as an input variable and a command to switch from single-axle mode to two-axle mode with a specified all-wheel drive factor, subsequently, according to the all-wheel drive factor, set a specified torque at least for the at least one internal combustion engine of the primary axle and to record an actual clutch torque of the automated transmission and finally, in a case in which a difference of the actual clutch torque and the sum target creep torque, compensate the difference by a specified torque for the at least one electric drive motor of the secondary axle.

7. The control device according to claim 6, wherein the sum target creep torque is specified by a transmission control unit when an accelerator pedal of the road-coupled hybrid vehicle is not operated.

8. The control device according to claim 6, wherein the command to switch from single-axle mode to two-axle mode with the specified all-wheel drive factor is generated when slip occurs while the road-coupled hybrid vehicle is at a standstill.

9. A non-transitory computer-readable medium storing a program for a control device for operating a road-coupled hybrid vehicle according to claim 6.

10. A road-coupled hybrid vehicle with a control device according to claim 6.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 shows a schematic representation of a road-coupled hybrid vehicle with the components essential for the control device according to the invention; and

[0024] FIG. 2 shows a diagram of the operation of the method that can be carried out by the electronic control unit according to the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

[0025] In FIG. 1 a so-called road-coupled hybrid vehicle F with a first electric drive motor 1 as the drive unit of the front axle VA (defined here as the secondary axle) and with an internal combustion engine 3 as a drive unit of the rear axle HA (defined here as the primary axle) are shown. The drive unit of the rear axle HA may contain a second electric motor 2 in addition to the internal combustion engine 3. Furthermore, an automatic transmission 4 (in particular a DCT transmission without a torque converter) with at least one controllable clutch 6 can be connected to the combustion engine 3 on the input side. Analogously, the invention is also applicable to a differently arranged sequence of the components 2, 3 and 4; for example, also for an arrangement in which the electric motor 2 is arranged between the internal combustion engine 3 and the automatic transmission 4. In another road-coupled hybrid vehicle according to the invention, the front axle VA could also be driven by an internal combustion engine and the rear axle by an electric motor. Finally, the hybrid vehicle has an electric energy storage device 7 which can be charged in particular when the electric drive motors 1 and/or 2 are operated regeneratively. A transmission control unit 8, which communicates with the drive control unit 5 according to the invention, is associated with the transmission 4.

[0026] The method for controlling the operation of the hybrid vehicle is carried out by the electronic control unit 5, which has an appropriately programmed functional module 10 as well as connections to the necessary sensors and actuators. According to the invention, the functional module 10 is realized, for example, in the form of a software program part (computer program product), the design and functioning of which will be discussed in more detail by the description of FIG. 2.

[0027] FIG. 2 shows the relationships between the parameters that are processed by the control unit 5 according to the invention: The sum target creep torque M_soll_K_ges is specified, for example by the transmission control unit 8. If the coupling torque M_ist_G in the transmission 4 cannot be controlled by the nominal torque M_soll_1 of the primary drive 3 (and possibly 2) to reach the sum target creep torque M_soll_K_ges, the target torque M_soll_2 of the secondary drive 1 compensates for the difference D of the actual coupling torque M_ist_G and the sum target creep torque M_soll_K_ges.

[0028] Preferably, the sum target creep torque M_soll_K_ges is specified by the transmission control unit 8 if the electronic control unit 5 generates a command to change from the all-wheel drive factor 100%i.e., from the single-axle mode with the primary axle HAto a two-axle or all-wheel drive mode (for example, 50%).

In Other Words:

[0029] In the case of a control device for the operation of a road-coupled hybrid vehicle with at least one electronic control unit 5, with a first drive unit 2 (and, if applicable, 3) associated with a primary axle HA and with a second drive unit 1 associated with a secondary axle VA, the drive unit of the primary axle HA has at least one internal combustion engine 3 and an automatic transmission 4 with an automatically controllable clutch 6 and the drive unit of the secondary axle VA has at least one electric drive motor 1. The control unit 5 is configured to receive a specified sum target creep torque M_soll_K_ges as the input variable and to receive a command to switch from single-axle mode to two-axle mode with a specified all-wheel drive factor (AWD). Subsequently, the control unit 5 uses an appropriately programmed functional module 10 according to the all-wheel drive factor AWD to set a predetermined torque M_soll_1 for the internal combustion engine 3 of the primary axle HA. Furthermore, the control unit 5 records the resulting actual coupling torque M_ist_G of the transmission 4, which is transmitted by the transmission control unit 8. If the functional module 10 detects a difference D of the actual coupling torque M_ist_G and the sum target creep torque M_soll_K_ges, it specifies a corresponding torque M_soll_2 for the electric drive motor 1 of the secondary axle VA to compensate for this difference D.

[0030] Preferably, the sum target creep torque M_soll_K_ges is specified by the transmission control unit 8 with the accelerator pedal FP not operated and with a driving position D or R of a selector switch 9 connected to the transmission control unit 8.

[0031] In particular, the command to switch from single-axle mode to two-axle mode with a specified all-wheel drive factor AWD is generated when slip occurs while at a standstill.