Internal-combustion engines – Engine speed regulator – Open loop condition responsive
Patent
1995-11-30
1997-03-04
Wolfe, Willis R.
Internal-combustion engines
Engine speed regulator
Open loop condition responsive
123586, F02D 910, F02D 1110, F02D 4118
Patent
active
056069510
DESCRIPTION:
BRIEF SUMMARY
This invention relates to the control of air flow to an internal combustion engine to enable efficient and controlled combustion of fuel supplied to the engine.
In a Drive-By-Wire (DBW) system, the driver has no direct mechanical control over either the fuel supply or air supply to an engine. Rather, the accelerator pedal, or throttle control, operated by the driver is typically utilised to set the position of a throttle valve of the engine induction system. The positioning of the throttle valve in turn provides a consequential air flow to the engine. This type of DBW system is commonly known in the field of four-stroke engine technology.
Other more advanced DBW systems may utilise the driver operated accelerator pedal, or throttle control, to generate a "demand" signal which is processed by an Electronic Control Unit (ECU) to provide the required air and/or fuel supply to the engine. Such a DBW system may be implemented in either an air based or fuel based system if desired.
For example, in a fuel based system wherein the fuelling rate is the primary control parameter, engine load control is accomplished by controlling the amount of fuel delivered to the engine. The operator demand signal is converted into a signal which represents the required or demanded fuelling rate for the engine. From this demanded fuelling rate, together with other engine operating parameters, the required or demanded air flow for the engine is determined and a throttle valve, normally electrically actuated, is controlled to enable the supply of this demanded air flow. Movement of the throttle valve may be accomplished by, for example, a stepper motor or a position feed-back controller acting on the throttle valve actuator.
In order to provide the demanded air flow, the throttle valve must be controlled or actuated such that it moves to a position corresponding to the demanded air flow. This may be accomplished by, for example, a feed-back control circuit which compares the actual air flow rate and the required or demanded air flow rate and then adjusts the throttle position accordingly. That is, the actual air flow as measured in the engine induction system is used to effect any adjustment to the position of the throttle valve until the demanded air flow is achieved. An example of such a fuel based DBW system is disclosed in Mikuni Kogyo Co Ltd's Australian Patent Application No. 66831/81.
However, it will be appreciated that the above described control strategy is not entirely satisfactory as it will suffer from a time lag in response because the throttle movement is dependent upon control signals which are the result of successive comparisons between the demanded air flow and the actual air flow of the engine as measured in the induction system. That is, the throttle valve is moved or driven to a certain position in response to the measured or actual air flow rate being compared with the demanded air flow rate. Hence, the control strategy requires to determine an error in the comparison between the actual air flow rate and the demanded air flow rate before the throttle is moved or actuated and numerous individual feed-back routines will typically be required before the throttle value reaches a position acceptably close to the required throttle position which corresponds to the demanded air flow. This causes a lag. Typically, this lag will be further compounded by the fact that the air flow will not instantaneously change with changes in throttle position. This overall lag in the response time has detrimental effects upon air/fuel ratio control.
The present invention is aimed at providing a method of operating an engine wherein the above described problem is overcome or substantially reduced.
With this object in view, the present invention provides a method of controlling the air supply to an internal combustion engine having a means to throttle the air flow to the engine comprising: driver initiated signal; actual rate of air supply with the determined air demand; air supply within acceptable operating limits of the determined a
REFERENCES:
patent: 4473052 (1984-09-01), Kamiyama et al.
patent: 4524745 (1985-06-01), Tominari et al.
patent: 4549517 (1985-10-01), Kamiyama
patent: 4763264 (1988-08-01), Okuno et al.
patent: 4765296 (1988-08-01), Ishikawa et al.
patent: 5080064 (1992-01-01), Buslepp et al.
patent: 5349932 (1994-09-01), Boverie et al.
patent: 5406920 (1995-04-01), Murata et al.
patent: 5526787 (1996-06-01), Pallett
Patent Abstracts of Japan, M454, p. 111, JP,A,60-192852, Oct. 1985.
Melbourne Keith
Southern Michael P.
Thompson Ian R.
Orbital Engine Company (Australia) Pty. Limited
Wolfe Willis R.
LandOfFree
Engine air supply systems does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Engine air supply systems, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Engine air supply systems will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2139413