Ventilation controls for dual-fuel engines

Patent metadata

Field	Value
Publication number	US-2017204792-A1
Application number	US-201715403895-A
Country	US
Kind code	A1
Filing date	Jan 11, 2017
Priority date	Jan 15, 2016
Publication date	Jul 20, 2017
Grant date	—

Abstract

One exemplary embodiment is a system comprising a dual-fuel engine structured to selectably combust a first fuel type and a second fuel type, and an electronic control system in operative communication with the dual-fuel engine. The electronic control system is structured to control a transition of the dual-fuel engine from a dual-fuel mode to a single-fuel mode. After initiating the transition from the dual-fuel mode to the single-fuel mode, the control system stops provision of the second fuel type, requires combustion using control parameters configured for the dual-fuel mode until a transition ventilation condition is satisfied, permits non-emergency commanded engine shutdown only if the transition ventilation condition is satisfied.

First claim

1 . A system comprising:
a dual-fuel engine structured to selectably combust a first fuel type and a second fuel type; and an electronic control system in operative communication with the dual-fuel engine, the electronic control system being structured to control a transition of the dual-fuel engine from a dual-fuel mode which provides the first fuel type and the second fuel type for combustion by the dual-fuel engine to a single-fuel mode which provides only the first type of fuel for combustion by the dual-fuel engine, wherein after initiating the transition from the dual-fuel mode to the single-fuel mode, the control system stops provision of the second fuel type, requires combustion using control parameters configured for the dual-fuel mode until a transition ventilation condition is satisfied and permits non-emergency commanded engine shutdown only if the transition ventilation condition is satisfied, and control a starting of the dual-fuel engine in the single-fuel mode, wherein after initiating the starting of the dual-fuel engine, provision of the first type of fuel is inhibited until a starting ventilation condition is satisfied.

2 . The system of claim 1 wherein the control system is configured to set the starting ventilation condition as not satisfied upon occurrence of an engine shutdown condition involving closure of the ASOV at a point in time when the engine ventilation condition is not satisfied.

3 . The system of claim 1 wherein the transition ventilation condition and the starting ventilation utilizes a ventilation threshold to evaluate whether the ventilation is complete.

4 . The system of claim 3 wherein the ventilation threshold is determined using a volume value accounting for a plurality of intake system components, a plurality of exhaust system components, and a displacement of the engine.

5 . The system of claim 3 wherein the ventilation threshold is determined using a volume margin of error factor.

6 . The system of claim 3 wherein the ventilation threshold is evaluated relative to one of a counter and a timer.

7 . The system of claim 3 wherein the ventilation threshold comprises the greater of a first cylinder bank ventilation threshold and a second cylinder bank ventilation threshold.

8 . A method of controlling a system including an engine and an electronic controller in operative communication with the engine, the method comprising:
operating the system in a dual-fuel combustion mode in which both diesel fuel and gaseous fuel are supplied to and combusted by the engine; commanding a transition from the dual-fuel mode to a diesel-only mode in which only diesel fuel is supplied to and combusted by the engine; and in response to the commanding the transition from the dual-fuel mode to the diesel-only mode: operating an actuator to stop supplying gaseous fuel to the engine, monitoring a ventilation condition of the engine, commanding operation of the engine using first combustion controls configured for the dual-fuel mode if the ventilation condition is not satisfied, inhibiting operation of a non-emergency engine shutdown command if the engine ventilation condition is not satisfied, and commanding operation of the engine using second combustion controls configured for the single-fuel mode if the engine ventilation condition is satisfied.

9 . The method of claim 8 wherein the monitoring the engine ventilation condition of the engine comprises monitoring whether a predetermined ventilation volume has been displaced by the engine.

10 . The method of claim 9 wherein the predetermined ventilation volume is determined based upon an intake system volume, an engine displacement volume and an exhaust system volume.

11 . The method of claim 8 comprising:
commanding starting of the engine in the diesel-only mode; and
in response to the act of commanding starting of the engine, monitoring the ventilation condition of the engine and inhibiting provision of diesel fuel to the engine if the engine ventilation condition is not satisfied.

12 . The method of claim 11 wherein the monitoring the engine ventilation condition of the engine comprises monitoring one of a timer value and a counter value.

13 . The method of claim 12 wherein the act of monitoring comprises one of decrementing and incrementing the one of the timer value and the counter value and evaluating the one of the time value and the counter value relative to a predetermined value indicating that the ventilation condition is satisfied.

14 . A method of controlling a system including a dual-fuel engine with an electronic controller in operative communication with the engine, the method comprising:
commanding operation of a starter motor to start the dual-fuel engine; evaluating whether starting ventilation is required to ventilate gaseous fuel from the system; if starting ventilation is required, inhibiting provision of diesel fuel to the engine until a ventilation condition is satisfied; and once the ventilation condition is satisfied, allowing provision of diesel fuel to the engine.

15 . The method of claim 14 wherein the ventilation condition is effective to ensure that a sufficient volume has been displaced by the engine to ventilate gaseous fuel from an intake system and an exhaust system.

16 . The method of claim 15 wherein the sufficient volume is determined based upon a plurality of calibratible values indicating volume information for a plurality of components of an intake system volume, a plurality of components of an exhaust system volume and the engine displacement.

17 . The method of claim 14 comprising:
after starting the engine, operating the system in a dual-fuel combustion mode in which both diesel fuel and gaseous fuel are supplied to and combusted by the engine;
commanding a transition from the dual-fuel mode to a diesel-only mode in which only diesel fuel is supplied to and combusted by the engine; and
in response to the commanding the transition from the dual-fuel mode to the diesel-only mode:
operating a valve to stop supplying gaseous fuel to the engine,
monitoring the ventilation condition,
commanding operation of the engine using first combustion controls configured for the dual-fuel mode if the ventilation condition is not satisfied.

18 . The method of claim 17 further comprising inhibiting operation of an non-emergency engine shutdown command if the engine ventilation condition is not satisfied.

19 . The method of claim 17 further comprising commanding operation of the engine using second combustion controls configured for the single-fuel mode if the engine ventilation condition is satisfied.

20 . The method of claim 17 wherein the ventilation condition is effective to ensure that a sufficient volume has been displaced by the engine to ventilate gaseous fuel from an intake system and an exhaust system.

Assignees

• Cummins Inc

Inventors

• Thomas Robert J
• Lambert David

Classifications

• F02D19/0615 Primary

  being initiated by automatic means, e.g. based on engine or vehicle operating conditions · CPC title

• F02D19/105

  operating in a special mode, e.g. in a liquid fuel only mode for starting · CPC title

• F02D41/0025

  Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures · CPC title

• F02D19/0647

  the gaseous fuel being liquefied petroleum gas [LPG], liquefied natural gas [LNG], compressed natural gas [CNG] or dimethyl ether [DME] · CPC title

• F02D41/062

  for starting (F02D41/061 takes precedence) · CPC title