# US 9,518,516 B2 · State-based diesel fueling for improved transient response in dual-fuel engine

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- Number: US 9,518,516 B2
- Document ID: US9518516B2
- Status: Granted
- Kind: B2
- Application number: 14/595,993
- Filed: 2015-01-13
- Published: 2016-07-14
- Granted: 2016-12-13
- Earliest claimed: 2015-01-13
- Assignees: Southwest Research Institute
- Applicants: Southwest Research Institute
- Inventors: Ryan C. Roecker; Jayant V. Sarlashkar; David P. Branyon; Timothy J. Callahan
- Web page: https://patentgrep.com/patent/US9518516B2

## CPC

- F02D 41/0002: {Controlling intake air}
- F02B 37/16: by bypassing charging air
- F02D 19/0642: {at least one fuel being gaseous, the other fuels being gaseous or liquid at standard conditions}
- F02D 19/0647: {the gaseous fuel being liquefied petroleum gas [LPG], liquefied natural gas [LNG], compressed natural gas [CNG] or dimethyl ether [DME]}
- F02D 19/10: peculiar to compression-ignition engines in which the main fuel is gaseous
- F02D 41/0025: {Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures}
- F02D 41/10: for acceleration
- F02D 41/0007: {for control of turbo-charged or super-charged engines (control of the pumps per se F02B37/12)}
- F02D 41/0027: {the fuel being gaseous (non-electrical control F02D19/02)}
- F02D 41/1458: {with determination means using an estimation}
- F02D 2041/1415: {using a state feedback or a state space representation}
- F02D 2200/0402: the parameter being determined by using a model of the engine intake or its components
- Y02T 10/12: Improving ICE efficiencies
- Y02T 10/30: Use of alternative fuels, e.g. biofuels
- Y02T 10/40: Engine management systems
- 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)
- F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G)
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A method, used with dual-fuel engine, of controlling the amount of diesel fuel delivered to the engine. The method compensates for the poor transient response of gaseous fueling. A controller receives a signal from the operator of the engine representing a desired torque, and based on this signal, determines a desired intake manifold state. It generates commands to various actuators to control the intake air and the intake gaseous fuel such that the desired intake manifold state will occur. The controller also receives sensor data from which the current in-cylinder state can be measured or estimated. It determines a current amount of diesel fuel based on the desired torque, the engine speed and the current in-cylinder state, and generates a diesel fueling command.

## Claims

### Claim 1

A method of controlling the amount of diesel fuel delivered to a dual-fuel internal combustion engine, the engine being fueled with both gaseous fuel and diesel fuel, comprising:
receiving a signal from the operator of the engine representing a desired torque;
determining a desired intake manifold pressure and a desired intake manifold oxygen fraction, based on the desired torque;
controlling flow actuators for at least the intake air flow and the intake gaseous fuel such that the desired intake manifold pressure and the desired intake manifold oxygen fraction will occur;
receiving sensor data from which the engine speed and a current in-cylinder state can be measured or estimated;
wherein the current in-cylinder state comprises at least an in-cylinder amount of gaseous fuel and an in-cylinder amount of oxygen;
determining a current amount of diesel fuel based at least on the desired torque, the engine speed and the current in-cylinder state; and
generating a diesel fueling command representing the current amount of diesel fuel.

### Claim 2 (depends on 1)

The method of claim 1, wherein the receiving step is performed by receiving an accelerator pedal position signal.

### Claim 3 (depends on 1)

The method of claim 1, wherein the desired intake manifold state comprises at least an intake manifold pressure value.

### Claim 4 (depends on 1)

The method of claim 1, wherein the engine has a throttle, and the controlling flow actuators step is performed by controlling at least the throttle.

### Claim 5 (depends on 1)

The method of claim 1, wherein the engine has a gaseous fuel intake valve, and the controlling flow actuators step is performed by controlling at least the gaseous fuel intake valve.

### Claim 6 (depends on 1)

The method of claim 1, wherein the engine has a compressor and compressor by-pass valve, and the controlling flow actuators step is performed by controlling at least the compressor bypass valve.

### Claim 7 (depends on 1)

The method of claim 1, wherein the gaseous fuel is natural gas.

### Claim 8

A controller for controlling the amount of diesel fuel delivered to a dual-fuel internal combustion engine, the engine being fueled with both gaseous fuel and diesel fuel, and the engine having a conventional engine control unit, comprising:
a processor and memory system programmed to perform the following tasks: to receive a signal from the operator of the engine representing a desired torque; to determine a desired intake manifold pressure and a desired intake manifold oxygen fraction, based on the desired torque; to control flow actuators for at least the intake air flow and the intake gaseous fuel such that the desired intake manifold pressure and desired intake manifold oxygen fraction will occur; to receive sensor data from which the engine speed and a current in-cylinder state can be measured or estimated; wherein the current in-cylinder state comprises at least an in-cylinder amount of gaseous fuel and an in-cylinder amount of oxygen; to determine a current amount of diesel fuel based at least on the desired torque, the engine speed and the current in-cylinder state; and to generate a diesel fueling command representing the current amount of diesel fuel.

### Claim 9 (depends on 8)

The controller of claim 8, wherein the controller receives an accelerator pedal position signal representing desired torque.

### Claim 10 (depends on 8)

The controller of claim 8, wherein the desired intake manifold state comprises at least an intake manifold pressure value.

### Claim 11 (depends on 8)

The controller of claim 8, wherein the engine has a throttle, and the controlling step is performed by controlling at least the throttle.

### Claim 12 (depends on 8)

The controller of claim 8, wherein the engine has a gaseous fuel intake valve, and the controlling step is performed by controlling at least the gaseous fuel intake valve.

### Claim 13 (depends on 8)

The controller of claim 8, wherein the engine has a compressor and compressor by-pass valve, and the controlling step is performed by controlling at least the compressor bypass valve.

### Claim 14 (depends on 8)

The controller of claim 8, wherein the gaseous fuel is natural gas.