# US 10,308,252 B2 · Method of controlling a powertrain

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- Number: US 10,308,252 B2
- Document ID: US10308252B2
- Status: Granted
- Kind: B2
- Application number: 15/701,802
- Filed: 2017-09-12
- Published: 2019-03-14
- Granted: 2019-06-04
- Earliest claimed: 2017-09-12
- Assignees: Ford Global Technologies, LLC
- Applicants: Ford Global Technologies, LLC
- Inventors: Yang Xu; Zhengyu Dai; Guopeng Hu; Hong Jiang; Bradley D. Riedle
- Web page: https://patentgrep.com/patent/US10308252B2

## CPC

- B60W 30/18054: {at stand still, e.g. engine in idling state (hill holding B60W30/18118)}
- F16H 63/502: {for smoothing gear shifts}
- B60W 10/02: including control of driveline clutches
- B60W 10/06: including control of combustion engines
- B60W 10/115: with planetary gears
- F16H 61/686: with orbital gears
- B60W 2510/0275: Clutch torque
- B60W 2510/1005: Transmission ratio engaged
- B60W 2520/04: Vehicle stop
- B60W 2540/10: Accelerator pedal position
- B60W 2540/12: Brake pedal position
- B60W 2710/027: Clutch torque
- B60W 2710/0666: Engine torque
- B60W 2710/1005: Transmission ratio engaged
- F16H 59/18: dependent on the position of the accelerator pedal
- F16H 2061/0488: {during range shift from neutral (N) to drive (D)}
- F16H 2200/2012: with four sets of orbital gears
- F16H 2200/2046: with six engaging means
- B60W: CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- F16H: GEARING

## Abstract

To reduce fuel consumption, a transmission is shifted into a neutral state, called neutral idle, when a vehicle stops in a drive mode. During a transition from a neutral idle state to an engaged state, the engine torque is controlled to avoid excessive shift energy and to mitigate acceleration drop. Specifically, the engine torque is set to a level equal to a sum of a transmission torque capacity and an offset, which is a function of accelerator pedal position. The transmission torque capacity is calculated based on the engaging shift element torque capacity and torque ratios associated with the kinematics and the torque converter. To accommodate noise factors such as variation over time, the offset function is adapted in response to measured clutch energy and acceleration drop.

## Claims

### Claim 1

A method of controlling a vehicle powertrain comprising:
disengaging a shift element in response to a vehicle stopping in a drive mode to place a transmission in a neutral state;
in response to release of a brake pedal or depression of an accelerator pedal, commanding an increase in a torque capacity of the shift element to transition from the neutral state to an engaged state; and
during the transition from the neutral state to the engaged state, commanding an engine torque equal to a sum of a transmission torque capacity and an offset, wherein the offset is a function of an accelerator pedal position.

### Claim 2 (depends on 1)

The method of claim 1 further comprising calculating the transmission torque capacity by multiplying the torque capacity of the shift element by a torque converter torque multiplication ratio.

### Claim 3 (depends on 2)

The method of claim 2 wherein calculating the transmission torque capacity further comprises multiplying by a torque ratio between the shift element and a turbine shaft.

### Claim 4 (depends on 1)

The method of claim 1 wherein a rate of increase of the torque capacity of the shift element during the transition is based on the accelerator pedal position.

### Claim 5 (depends on 1)

The method of claim 1 further comprising, in response to a clutch energy during the transition exceeding a threshold, decreasing the offset such that, during a subsequent transition from the neutral state to the engaged state at the same accelerator pedal position, a lower engine torque is commanded.

### Claim 6 (depends on 5)

The method of claim 5 further comprising, in response to the clutch energy during the transition not exceeding the threshold, increasing the offset such that, during the subsequent transition from the neutral state to the engaged state at the same accelerator pedal position, a higher engine torque is commanded.

### Claim 7 (depends on 6)

The method of claim 6 wherein the offset is increased by an amount that is proportional to an acceleration drop during the transition.

### Claim 8

A powertrain control method comprising:
while a drive mode is selected, transitioning from a neutral state to an engaged state by increasing a shift element torque capacity; and
during the transition, commanding an engine torque equal to a sum of a transmission torque capacity and an offset, wherein the transmission torque capacity is a function of the shift element torque capacity and the offset is a function of an accelerator pedal position.

### Claim 9 (depends on 8)

The powertrain control method of claim 8 wherein a rate of increase of the shift element torque capacity during the transition is based on the accelerator pedal position.

### Claim 10 (depends on 8)

The powertrain control method of claim 8 further comprising, in response to a clutch energy during the transition exceeding a threshold, decreasing the offset such that, during a subsequent transition from the neutral state to the engaged state at the same accelerator pedal position, a lower engine torque is commanded.

### Claim 11 (depends on 8)

The powertrain control method of claim 8 further comprising, in response to a clutch energy during the transition not exceeding a threshold, increasing the offset such that, during a subsequent transition from the neutral state to the engaged state at the same accelerator pedal position, a higher engine torque is commanded.

### Claim 12 (depends on 11)

The powertrain control method of claim 11 wherein the offset is increased by an amount that is proportional to an acceleration drop during the transition.

### Claim 13

A powertrain comprising:
an engine;
a transmission; and
a controlled programmed to
shift the transmission from a neutral state to an engaged state by increasing a torque capacity of a shift element to increase a transmission torque capacity, and
during the shift, command an engine torque equal to a sum of the transmission torque capacity and an offset, wherein the offset is a function of an accelerator pedal position.

### Claim 14 (depends on 13)

The powertrain of claim 13 wherein the controller is programmed to increase the torque capacity of the shift element during the shift at a rate based on the accelerator pedal position.

### Claim 15 (depends on 13)

The powertrain of claim 13 wherein the controller is further programmed to, in response to a clutch energy during the shift exceeding a threshold, command a lower engine torque during a subsequent shift from the neutral state to the engaged state at the same accelerator pedal position.

### Claim 16 (depends on 13)

The powertrain of claim 13 wherein the controller is further programmed to, in response to a clutch energy during the shift not exceeding a threshold, command a higher engine torque during a subsequent shift from the neutral state to the engaged state at the same accelerator pedal position.

### Claim 17 (depends on 16)

The powertrain of claim 16 wherein the difference between the commanded engine torque during the subsequent shift and the commanded engine torque during the shift is proportional to an acceleration drop during the shift.