Control of combustion mixtures and variability thereof with engine load
An internal combustion engine can be operated in response to a received first throttle control input in a first operating regime that includes delivering a first air-fuel mixture having a first air/fuel ratio to a combustion volume to deliver a first output power in a first output power range between zero and a transition output power level. The engine can be operated in response to a received second throttle control input in a second operating regime that includes delivering a second air/fuel ratio richer than the first air/fuel ratio to the combustion volume to deliver a second output power in a second output power range between the transition output power level and a maximum output power level. The first throttle control input can include activation of a throttle control device against a first control resistance provided by the throttle control device, and the second throttle control input can include activation of the throttle control device against a second control resistance provided by the throttle control device and that is greater than the first control resistance. Related methods, systems, and article of manufacture are described.
1. A method comprising:
activating a throttle control device, the throttle control device causing operation of a mixture control carburetor to provide variation between at least a first air/fuel ratio and a second air/fuel ratio, the mixture control carburetor comprising separately actuated first and second controls, the first control determining an amount of air flowing past a fuel source and the second control moving a tapered needle that is extendible and retractable into an orifice or jet to control a fuel delivery area of the orifice or jet; and
delivering, to a combustion volume of an internal combustion engine, an air-fuel mixture comprising a delivered air/fuel ratio provided by the mixture control carburetor.
2. The method of claim 1 , further comprising receiving a first throttle control input comprising activation of the throttle control device within a first control range, the first throttle control input corresponding to a first output power of the internal combustion engine, and operating the internal combustion engine in a first operating regime in response to the received first throttle control input.
3. The method of claim 2 , further comprising receiving a second throttle control input comprising activation of the throttle control device within a second control range, the second throttle control input corresponding to a second output power of the internal combustion engine, and operating the internal combustion engine in a second operating regime in response to the received second throttle control input.
4. The method of claim 3 , further comprising providing a feedback to indicate that the second control range has been activated.
5. The method of claim 3 , wherein the first operating regime further comprises a first ignition timing and the second operating regime further comprises a second ignition timing that is retarded relative to the first ignition timing.
6. The method of claim 1 , wherein variation between the first air/fuel ratio and the second air/fuel ratio is provided by actuation of a throttle to control airflow to the internal combustion engine and concurrent, independent control of a delivery rate of fuel via one or more fuel injectors.
7. The method of claim 6 , further comprising controlling the delivery rate of fuel via the one or more fuel injectors by a programmable processor that receives commands from the throttle control device.
8. The method of claim 1 , wherein the first control determining the amount of air flowing past the fuel source comprises a movable slide.
9. An internal combustion engine having an internal combustion volume, the internal combustion engine comprising:
a control mechanism configured to operate in a first operating regime, the first operating regime comprising delivering inlet air and fuel to produce a first air-fuel mixture within the combustion volume, the first air-fuel mixture comprising a first air/fuel ratio, the control mechanism further configured to operate in a second operating regime comprising delivering inlet air and fuel to produce a second air-fuel mixture within the combustion volume, the second air-fuel mixture comprising a second air/fuel ratio that is richer than the first air/fuel ratio, the control mechanism comprising a mixture control carburetor operable to provide variation between at least the first air/fuel ratio and the second air/fuel ratio, the mixture control carburetor comprising a first control for determining an amount of air flowing past a fuel source and a second control for positioning a tapered needle that is extendible and retractable into an orifice or jet to control a fuel delivery area of the orifice or jet.
10. The system of claim 9 , further comprising a user-operable throttle control device operable to receive a first throttle control input comprising activation of the throttle control device within a first control range, and a second throttle control input comprising activation of the throttle control device within a second control range.
11. The system of claim 10 , further comprising a feedback system that provides a feedback to indicate that the second control range has been activated, the feedback system comprising at least one of an increased throttle control device motion resistance mechanism that increases a resistance to motion of the throttle control device in the second control range relative to the first control range, a visual feedback, an auditory feedback, and a tactile feedback that is not related to motion resistance of the throttle control device.
12. The system of claim 9 , wherein the first operating regime further comprises a first ignition timing and the second operating regime further comprises a second ignition timing that is retarded relative to the first ignition timing.
13. The system of claim 9 , wherein the first control for determining the amount of air flowing past the fuel source comprises a movable slide.
14. The system of claim 9 , wherein the mixture control carburetor comprises one or more airflow dilution features that provide airflow-independent control of a required air/fuel ratio.
15. The system of claim 14 , wherein the one or more airflow dilution features comprise a secondary throttle metering airflow through a second air passage that dilutes air passing through a first airflow passage that comprises a controlled rate of fuel delivery from an orifice or jet.
16. A system comprising:
a mixture control carburetor comprising at least one of:
a variable fuel delivery rate feature providing airflow-independent control of a required air/fuel ratio, the variable fuel delivery rate feature comprising separately actuated first and second controls, the first control determining an airflow throat size and the second control positioning a tapered needle that is extendible and retractable into an orifice or jet to control a fuel delivery area of the orifice or jet, and
an airflow dilution feature providing airflow-independent control of the required air/fuel ratio, the airflow dilution feature comprising separately actuated first and second controls, the first control controlling an amount of air flowing past a fuel source and the second control positioning the orifice or jet into and out of which the tapered needle is moved to control a fuel delivery area of the orifice or jet.
17. The mixture control carburetor of claim 16 , wherein the fuel mixture control mechanism is configured to receive at least a first throttle control input and a second throttle control input from a throttle control device, the first throttle control input comprising activation of a throttle control device within a first control range, the first throttle control input corresponding to a first output power of an internal combustion engine in a first output power range between zero and a transition output power level, the second throttle control input comprising activation of the throttle control device within a second control range, the second throttle control input corresponding to a second output power of the internal combustion engine in a second output power range between the transition output power level and a maximum output power level of the internal combustion engine.
18. The mixture control carburetor of claim 17 , wherein the fuel mixture control mechanism produces a first air-fuel mixture comprising a first air/fuel ratio in response to receiving the first throttle control input, and produces a second air-fuel mixture comprising a second air/fuel ratio in response to receiving the second throttle control input, the second air/fuel ratio being richer than the first air/fuel ratio.
19. The mixture control carburetor of claim 17 , wherein the first control comprises a movable slide.
20. The mixture control carburetor of claim 19 , wherein the tapered needle is attached to and moves with the moveable slide.