# US 8,764,606 B2 · Rolling neutral mode control systems and methods

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- Number: US 8,764,606 B2
- Document ID: US8764606B2
- Status: Granted
- Kind: B2
- Application number: 13/151,692
- Filed: 2011-06-02
- Published: 2012-12-06
- Granted: 2014-07-01
- Earliest claimed: 2011-06-02
- Assignees: GM Global Technology Operations LLC
- Applicants: Richard A. Weaver; Kenneth K. Lang
- Inventors: Richard A. Weaver; Kenneth K. Lang
- Web page: https://patentgrep.com/patent/US8764606B2

## CPC

- B60W 10/06: including control of combustion engines
- B60W 10/113: with two input flow paths, e.g. double clutch transmission selection of one of the torque flow paths by the corresponding input clutch
- B60W 30/18072: {Coasting}
- B60W 2030/18081: {With torque flow from driveshaft to engine, i.e. engine being driven by vehicle}
- B60W 2030/1809: {Without torque flow between driveshaft and engine, e.g. with clutch disengaged or transmission in neutral}
- B60W 2540/103: Accelerator thresholds, e.g. kickdown
- B60W 2540/16: Ratio selector position
- B60W 2710/0627: Fuel flow rate
- B60W 2710/1066: Transmission of zero torque
- F02D 41/123: {the fuel injection being cut-off}
- 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
- F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W)

## Abstract

An engine control module includes a deceleration fuel cutoff (DFCO) module, an actuator control module, and a rolling neutral (RN) module. The DFCO module determines whether to disable provision of fuel to an engine when a vehicle speed is greater than zero and selectively generates a DFCO signal based on the determination. The actuator control module disables the provision of fuel to the engine when the DFCO signal is generated. The RN module selectively generates an RN mode signal in response to a determination that the DFCO module is not generating the DFCO signal. The actuator control module controls the provision of fuel to the engine based on a desired engine speed when the RN mode signal is generated. A transmission control module disengages first and second input clutches of a dual clutch transmission (DCT) to decouple the DCT from the engine when the RN mode signal is generated.

## Claims

### Claim 1

A system for a vehicle, comprising:
an engine control module comprising:
a deceleration fuel cutoff (DFCO) module that determines whether to disable provision of fuel to an engine when a vehicle speed is greater than zero and that selectively generates a DFCO signal based on the determination;
an actuator control module that disables the provision of fuel to the engine when the DFCO signal is generated; and
a rolling neutral (RN) module that selectively generates an RN mode signal in response to a determination that the DFCO module is not generating the DFCO signal,
wherein the actuator control module controls the provision of fuel to the engine based on a desired engine speed when the RN mode signal is generated; and
a transmission control module that disengages first and second input clutches of a dual clutch transmission (DCT) to decouple the DCT from the engine when the RN mode signal is generated.

### Claim 2 (depends on 1)

The system of claim 1 wherein the RN module generates the RN mode signal when the DFCO module is not generating the DFCO signal and a park, reverse, neutral, drive lever (PRNDL) is in a drive position.

### Claim 3 (depends on 1)

The system of claim 1 wherein the RN module generates the RN mode signal when the DFCO module is not generating the DFCO signal and an accelerator pedal position is less than a predetermined position.

### Claim 4 (depends on 1)

The system of claim 1 wherein the RN module generates the RN mode signal when the DFCO module is not generating the DFCO signal and a gear selected within the DCT is less than a predetermined gear.

### Claim 5 (depends on 1)

The system of claim 1 wherein the RN module generates the RN mode signal when the DFCO module is not generating the DFCO signal and an acceleration of the vehicle is within a predetermined range.

### Claim 6 (depends on 1)

The system of claim 1 further comprising a torque request module that generates a torque request based on an accelerator pedal position and the vehicle speed,
wherein the RN module generates the RN mode signal when the DFCO module is not generating the DFCO signal and the torque request is less than a predetermined torque.

### Claim 7 (depends on 1)

The system of claim 1 further comprising a torque request module that generates a torque request based on an accelerator pedal position and the vehicle speed,
wherein the RN module generates the RN mode signal when the DFCO module is not generating the DFCO signal and at least two of:
the torque request is less than a predetermined torque;
a gear selected within the DCT is less than a predetermined gear;
the accelerator pedal position is less than a predetermined position;
a park, reverse, neutral, drive lever (PRNDL) is in a drive position; and
an acceleration of the vehicle is within a predetermined range.

### Claim 8 (depends on 1)

The system of claim 1 further comprising a torque request module that generates a torque request based on an accelerator pedal position and the vehicle speed,
wherein the RN module generates the RN mode signal when the DFCO module is not generating the DFCO signal, the torque request is less than a predetermined torque; a gear selected within the DCT is less than a predetermined gear; the accelerator pedal position is less than a predetermined position; a park, reverse, neutral, drive lever (PRNDL) is in a drive position; and an acceleration of the vehicle is within a predetermined range.

### Claim 9 (depends on 1)

The system of claim 1 wherein the RN module stops generating the RN mode signal when an increase in the vehicle speed while the RN mode signal is generated is greater than a predetermined speed increase,
wherein the transmission control module selectively engages one of the first and second input clutches of the DCT when the RN module stops generating the RN mode signal.

### Claim 10 (depends on 9)

The system of claim 9 further comprising a torque request module that generates a torque request based on an accelerator pedal position and the vehicle speed,
wherein the actuator control module controls the provision of fuel to the engine based on the torque request after the RN module stops generating the RN mode signal.