GB2301863A - Control of spark ignition engine charge intake throttling - Google Patents
Control of spark ignition engine charge intake throttling Download PDFInfo
- Publication number
- GB2301863A GB2301863A GB9511458A GB9511458A GB2301863A GB 2301863 A GB2301863 A GB 2301863A GB 9511458 A GB9511458 A GB 9511458A GB 9511458 A GB9511458 A GB 9511458A GB 2301863 A GB2301863 A GB 2301863A
- Authority
- GB
- United Kingdom
- Prior art keywords
- engine
- valve
- throttles
- shut
- throttle
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D17/00—Controlling engines by cutting out individual cylinders; Rendering engines inoperative or idling
- F02D17/02—Cutting-out
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D9/00—Controlling engines by throttling air or fuel-and-air induction conduits or exhaust conduits
- F02D9/02—Controlling engines by throttling air or fuel-and-air induction conduits or exhaust conduits concerning induction conduits
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D9/00—Controlling engines by throttling air or fuel-and-air induction conduits or exhaust conduits
- F02D9/08—Throttle valves specially adapted therefor; Arrangements of such valves in conduits
- F02D9/10—Throttle valves specially adapted therefor; Arrangements of such valves in conduits having pivotally-mounted flaps
- F02D9/109—Throttle valves specially adapted therefor; Arrangements of such valves in conduits having pivotally-mounted flaps having two or more flaps
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D9/00—Controlling engines by throttling air or fuel-and-air induction conduits or exhaust conduits
- F02D9/08—Throttle valves specially adapted therefor; Arrangements of such valves in conduits
- F02D9/10—Throttle valves specially adapted therefor; Arrangements of such valves in conduits having pivotally-mounted flaps
- F02D9/109—Throttle valves specially adapted therefor; Arrangements of such valves in conduits having pivotally-mounted flaps having two or more flaps
- F02D9/1095—Rotating on a common axis, e.g. having a common shaft
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D9/00—Controlling engines by throttling air or fuel-and-air induction conduits or exhaust conduits
- F02D9/02—Controlling engines by throttling air or fuel-and-air induction conduits or exhaust conduits concerning induction conduits
- F02D2009/0201—Arrangements; Control features; Details thereof
- F02D2009/0272—Two or more throttles disposed in series
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D9/00—Controlling engines by throttling air or fuel-and-air induction conduits or exhaust conduits
- F02D9/02—Controlling engines by throttling air or fuel-and-air induction conduits or exhaust conduits concerning induction conduits
- F02D2009/0201—Arrangements; Control features; Details thereof
- F02D2009/0279—Throttle valve control for intake system with two parallel air flow paths, each controlled by a throttle, e.g. a resilient flap disposed on a throttle
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Control Of Throttle Valves Provided In The Intake System Or In The Exhaust System (AREA)
Abstract
A shut-off valve 32 in series with one of parallel synchronously operated throttle valves 24, 26 is closed or fully opened in response to a change in engine operating mode which would otherwise involve a change in engine output torque. The mode change may be a change in the number of operating cylinders or intake valves, in compression ratio or intake passage geometry or fuel/air ratio. A valve (28, Fig.3) in a by-pass around the valves 26, 32 or the ignition timing may be adjusted to compensate for minor torque variations. The valves 24, 26 may be electronically synchronously operated.
Description
Control of an internal combustion engine
The present invention relates to the control of a spark ignition internal combustion engine that has different operating modes, in which changing between operating modes involves a step change in an operating parameter. The step change in a parameter may be a step change in engine displacement brought about by cylinder disablement, a step change in average air-fuel ratio calibration resulting from switching between a lean-burn mode and a stoichiometric mode, a step change in thermal efficiency brought by changing the compression ratio, or a step change in volumetric efficiency brought about by changing the geometry of the valve train, the intake manifold, or the intake port.
When a mode change takes place, the engine will tend to produce a sudden increase or decrease in output torque which, unless the throttling of the air intake system is modified at the same time as the mode change, will be disconcerting to the driver.
One could resort to an electronic throttle in which the position of the throttle valve is electrically controlled by a control circuit to match the engine output torque to a demand signal produced by the driver. Such a system, often referred to as "drive by wire because the driver does not directly control the throttle, is not generally acceptable in the context of motor vehicles for safety reasons. Though such systems are used in aeroplanes, the complexity that must be introduced into the control system to allow for all eventualities makes it prohibitively expensive for motor vehicles.
Furthermore, even such a system will have a finite response time to the abrupt change in the engine operating parameter and relying on closed loop feedback control would not be sufficient to render a mode change imperceptible. The control system would need to be designed to bring about an immediate step change in the throttle valve position at the same time as the engine mode is changed. Thus the control system would need to store for each engine operating point, two throttle valve positions that are selected in dependence upon the operating mode of the engine.
There are known in the prior art several systems which address this problem in the one case where the mode change involves changing the number of firing cylinders in a multicylinder engine (see for example US-A-4,348,994). The cylinders are arranged in two banks supplied by respective throttles that are isolated from one another at their downstream ends, each throttle leading to a different bank of cylinders. When one bank is to be prevented from firing, the throttle leading to that bank is closed off by a diverter valve and the air that would normally be sent to that bank of cylinders is instead diverted to the other bank of cylinders, thereby counteracting to a certain extent the effect of the mode change.
In such a design, the two throttles must of necessity be identical if the engine is to be correctly balanced when all cylinders are firing. This however is not ideal as a doubling of the throttle cross-section to the firing cylinders will cause an abrupt increase in engine output torque because of the increased efficiency in the cylinder disablement mode of operation.
The present invention seeks to provide improved driveability in an engine having different operating modes by making changes in operating mode less perceptible.
According to the present invention, there is provided a spark ignition internal combustion engine having different operating modes, in which changing between modes involves a step change in an engine operating parameter, the engine air intake system having two or more air supply throttles arranged in parallel with one another in the intake manifold of the engine, being connected to one another only at their upstream and downstream ends, each having a respective throttle valve arranged therein, the valves in the two throttles being arranged to operate in synchronism with one another, wherein at least one of the throttles further has arranged therein a shut-off valve which, in use, is operated at the same time as the switching between modes takes place, the position of the shut-off valve not being itself responsible for determining the engine operating mode, and wherein the relative dimensions of the throttles are selected such that for any given position of the throttle valves substantially the same engine output torque will be produced in a first operating mode with the shut-off valve in one position as will be produced in a second operating mode with the shut-off valve in the other position.
In the present invention, which is applicable to engines in which the changes in operating mode are not only cylinder disablement but any other of the mode changes mentioned above, an imperceptible changeover between modes can be achieved without resorting to a drive by wire system. One of the throttles provides the full air requirement in the first mode of operation throughout the engine operating range whereas when the other throttle(s) operate(s) instead of or in parallel with the first throttle, the intake system will deliver the required air flow to the engine in the second mode of operation to achieve the same output torque at the same throttle valve position.At all times, the two throttles are in a position to deliver the appropriate air flow to match the required torque output from the engine for each mode and one needs only to switch throttles into or out of the intake system at the same time as changing modes to avoid an abrupt change in the output torque.
At least the first throttle valve in the present invention is moved directly in response to the throttle pedal operated by the driver. The second or the remaining throttle valves must at all times be in a position to provide the required additional air flow, should the engine mode be changed, and they are moved to shadow the current position of the first throttle valve. If desired, other engine parameters may also be taken into consideration in setting the position of the second or remaining throttle valves. The further throttle valves may thus be directly linked to the first throttle valve, or they may be controlled mechanically or electrically to follow a predetermined function of the position of the first throttle valve and to allow for the effect of other operating parameters.
The required size of the throttle valve opening for any air mass flow can be derived from two equations. The first equation relates to the demand flow from the engine which is a function of engine intake vacuum, air fuel ratio, engine cylinder swept volume and engine speed. The second equation relates to supply flow through the throttle which is a function of the throttle valve opening area, air density and pressure drop across the valve. Since the supply flow must equal the demand flow, the orifice area for each operating mode can be calculated by combining the two equations. This required throttle valve opening may then be provided by following one of two possible design approaches.
The first approach is to change the throttle valve angle and keep the same throttle size. The second approach is to change the throttle size but to keep the same throttle valve angle.
The first approach is to use an electronic throttle. This could prove very complicated because the variation of the air mass flow with throttle valve angle is highly non-linear. Whilst such a system may be used in some applications where it is necessary for it to take over the primary control of the engine in a continuously variable manner, it would be unjustifiable because of the significant increase in complexity and cost if the purpose for using it is merely to overcome a driveability refinement problem.
Such a problem occurs only occasionally and a simpler method of correction is available stemming from the fact that the relative effect of the step change in operating mode is readily quantifiable even though the absolute effect may not be accurately predicted.
The second approach exploits the quantifiable relative effect of the step change and is that of the preferred embodiment of the present invention. This is based on the realisation that by keeping the throttle valve angle the same and switching over to a different scaled size for the throttle with the change in operating mode, the same non-linearity of the throttle valve angle function will be built into the scaled size. This scaled size can be readily determined by taking into account the ratios of the parameters that are being changed or, better still, empirically by selecting the size ratio of the throttle that produces the same engine output torque. The resulting intake system would retain the conventional mechanical link with the driver's accelerator pedal and the switching of the operating mode would be insensitive to the pedal position.
In one category of changes of operating mode which is substantially engine speed independent, for example, switching to disable or enable a bank of engine cylinders, switching from lean-burn mode to stoichiometric mode and switching between two compression ratios, the scaled size of the throttle will be substantially constant for each operating mode across the engine speed range and will require only minor trimming to allow for small deviations.
In another category of changes in operating mode which is engine speed dependent, for example, switching of the setting of a variable valve train or a variable intake system and switching to disable or enable one intake port or intake valve in an engine having two intake valves per cylinder, the scaled size of the throttle can be selected to be correct without changing the throttle valve angle for a particular engine speed, which is predetermined to be the speed at which the change in operating mode will take place.
In both categories, regardless of the engine load and demand pedal position, the throttle valves are permanently in the correct position to permit an imperceptible mode change.
The invention will now be described further, by way of example, with reference to the accompanying drawings, in which:
Figure 1 is a schematic section through part of an
intake system of an engine of the present invention,
Figure 2 is an end view of the part of the intake
system illustrated in Figure 1, and
Figure 3 is a side view of a modification of the part
of the intake system illustrated in Figure 1, which
include a variable bypass for effecting fine trimming of
the air intake mass flow.
In Figures 1 and 2, an intake pipe 12 has two distinct intake throttles 14 and 16 with respective butterfly valves 24 and 26 on a common spindle 20. In addition the smaller of the two throttles 16 has a shut-off valve in the form of a butterfly valve 32 with an operating spindle 30. The embodiment of Figure 3 additionally includes a bypass pipe 18 with a variable valve 28 that operates in the manner of an idle speed control valve in some conventional systems.
The bypass pipe 18 in this case has a much smaller crosssection than the two main throttles 14 and 16 and is used only for fine trimming of the air intake mass flow.
The two throttles 14 and 16 are geometrically similar so that the ratio of their effective through flow crosssections is constant for all positions of the spindle 20.
This ratio is empirically selected such that for any position of the spindle 20 the same engine output torque will be produced in the first operating mode with the shutoff valve 32 closed as will be produced in the second operating mode with the shut-off valve 32 open. Because of this dimensioning of the throttles, a mode change accompanied by simultaneous change in the position of the shut-off valve 32 will produce no perceptible change in the output torque.
The throttle valve spindle 20 is directly operated by the driver's accelerator pedal and it serves to open and close both the butterfly valves 24 and 26 in dependence upon the position of the accelerator pedal. The spindle 30 for the shut-off valve 32 on the other hand it controlled automatically during changes between operating modes.
If one takes as an example a mode change involving disablement of half of the engine cylinders, the change will be imperceptible if substantially the same total air flow is fed to the firing cylinders. This involves substantially doubling the through flow cross-section of the intake system and this is what is achieved by connecting the throttle 16 in parallel with the throttle 14, without moving the throttle valves 24 and 26. In practice, the air flow need not be doubled because the change in mode will itself bring about improved engine efficiency and it is for this reason that the throttle 16 is illustrated as slightly smaller than the throttle 14.
This embodiment with ganged butterfly valves 24 and 26 and a single shut-off valve 32 makes for a particularly elegant and inexpensive solution to the problem of jerkiness during mode changes but other configurations may be adopted to achieve the same effect.
For example one could use two shut-off valves to switch between two throttles each dimensioned to provide on its own the required air flow in a respective one of the two operating modes. Furthermore one may use more than two throttles connected in parallel to allow for an engine having more than two operating modes.
As a further possibility, where during a mode change the required air flows in the different operating modes are not always in the same fixed ratio to one another, the butterfly valve 26 may be uncoupled from the butterfly valve 24 and controlled electrically or by a complex mechanical linkage such that the butterfly 26 shadows the movement of the butterfly 24, being thereby controlled always to be in the correct position to effect the correct change in the crosssection of the intake system should a change of operating mode be initiated. It is however expected that in most situations by suitably scaling two ganged throttles it will be possible to achieve smooth mode changes without the complexity of the above control system.
It is not crucial that a mode change be accompanied by no change whatever in the output torque because minor variations can either be corrected by the driver subconsciously or they may be reduced further by fine tuning of other operating parameters. For example in the embodiment of Figure 3 a small bypass valve 28 acting in the same way as an idle speed control valve may be used to trim the air flow. As a further example the ignition timing may be modified temporarily to smooth the changes.
Claims (5)
1. A spark ignition internal combustion engine having different operating modes, in which changing between modes involves a step change in an engine operating parameter, the engine air intake system having two or more air supply throttles arranged in parallel with one another in the intake manifold of the engine, being connected to one another only at their upstream and downstream ends, each having a respective throttle valve arranged therein, the valves in the two throttles being arranged to operate in synchronism with one another, wherein at least one of the throttles further has arranged therein a shut-off valve which, in use, is operated at the same time as the switching between modes takes place, the position of the shut-off valve not being itself responsible for determining the engine operating mode, and wherein the relative dimensions of the throttles are selected such that for any given position of the throttle valves substantially the same engine output torque will be produced in a first operating mode with the shut-off valve in one position as will be produced in a second operating mode with the shut-off valve in the other position.
2. An engine as claimed in claim 1, wherein the throttles are geometrically similar and the throttle valves are mounted on a common spindle.
3. An engine as claimed in claim 2, wherein the spindle is directly connected to the accelerator demand pedal and the shut-off valve is automatically operated during changes between operating modes.
4. An engine as claimed in any preceding claim, wherein means are provided for further fine tuning the engine output torque during mode changes by making minor modifications to the intake air mass flow using a small bypass valve or by temporarily altering the ignition timing.
5. An engine having an intake system constructed, arranged and adapted to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9511458A GB2301863A (en) | 1995-06-06 | 1995-06-06 | Control of spark ignition engine charge intake throttling |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9511458A GB2301863A (en) | 1995-06-06 | 1995-06-06 | Control of spark ignition engine charge intake throttling |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9511458D0 GB9511458D0 (en) | 1995-08-02 |
| GB2301863A true GB2301863A (en) | 1996-12-18 |
Family
ID=10775616
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9511458A Withdrawn GB2301863A (en) | 1995-06-06 | 1995-06-06 | Control of spark ignition engine charge intake throttling |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2301863A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2355494A (en) * | 1999-10-18 | 2001-04-25 | Ford Global Tech Inc | Mode transition control in a direct injection i.c.engine system |
| GB2355496A (en) * | 1999-10-18 | 2001-04-25 | Ford Global Tech Inc | Mode transition control in a direct injection i.c. engine system |
| WO2018113988A1 (en) * | 2016-12-22 | 2018-06-28 | Volvo Truck Corporation | An internal combustion engine |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4207856A (en) * | 1977-07-15 | 1980-06-17 | Nissan Motor Company, Limited | I.C. Engine operable in party-cylinder mode |
| GB2116630A (en) * | 1982-01-27 | 1983-09-28 | Mitsubishi Motors Corp | Controlling idling of an i.c. engine with a variable number of effective cylinders |
-
1995
- 1995-06-06 GB GB9511458A patent/GB2301863A/en not_active Withdrawn
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4207856A (en) * | 1977-07-15 | 1980-06-17 | Nissan Motor Company, Limited | I.C. Engine operable in party-cylinder mode |
| GB2116630A (en) * | 1982-01-27 | 1983-09-28 | Mitsubishi Motors Corp | Controlling idling of an i.c. engine with a variable number of effective cylinders |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2355494A (en) * | 1999-10-18 | 2001-04-25 | Ford Global Tech Inc | Mode transition control in a direct injection i.c.engine system |
| GB2355496A (en) * | 1999-10-18 | 2001-04-25 | Ford Global Tech Inc | Mode transition control in a direct injection i.c. engine system |
| US6244242B1 (en) | 1999-10-18 | 2001-06-12 | Ford Global Technologies, Inc. | Direct injection engine system and method |
| GB2355494B (en) * | 1999-10-18 | 2004-01-14 | Ford Global Tech Inc | Direct injection engine system |
| GB2355496B (en) * | 1999-10-18 | 2004-02-18 | Ford Global Tech Inc | Direct injection engine system and method |
| WO2018113988A1 (en) * | 2016-12-22 | 2018-06-28 | Volvo Truck Corporation | An internal combustion engine |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9511458D0 (en) | 1995-08-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4418673A (en) | Electronic control fuel injection system for spark ignition internal combustion engine | |
| US4524745A (en) | Electronic control fuel injection system for spark ignition internal combustion engine | |
| US4924840A (en) | Fast response exhaust gas recirculation (EGR) system | |
| US6016788A (en) | Fuel injection control system for a diesel engine | |
| US6910460B2 (en) | Engine air-fuel ration control method with venturi type fuel supply device and fuel control appliance including the method | |
| GB2301863A (en) | Control of spark ignition engine charge intake throttling | |
| US6158414A (en) | Mode control for lean burn engines | |
| JPH03225044A (en) | Control device for internal combustion engine | |
| US5081974A (en) | Fuel control apparatus of an engine | |
| JPH0563609B2 (en) | ||
| JP2969318B2 (en) | Governor device for internal combustion engine | |
| JPS63124854A (en) | Output control device for gas fuel engine | |
| JP2621033B2 (en) | Idle speed control method for internal combustion engine | |
| EP0877859B1 (en) | Fuel metering system for an internal combustion engine | |
| JP2600833Y2 (en) | Boost compensator pressure regulator | |
| JP2021121731A (en) | Control device for internal combustion engine | |
| JPH0374530A (en) | Intake air quantity control device for engine | |
| JPS62191628A (en) | Intake path device for multicylinder internal combustion engine | |
| JPS62265446A (en) | Idling revolution-number controller for internal combustion engine | |
| JPH07167025A (en) | Ignition tining control device | |
| JPS6217318A (en) | Air intake device of engine | |
| JPH08319861A (en) | Method and equipment for controlling internal combustion engine | |
| JPS6045737A (en) | Controller for engine with regulated number of cylinders | |
| JPH0417742A (en) | Air-fuel ratio controller of lean-burn gasoline supercharged internal combustion engine | |
| JPH0686823B2 (en) | Engine intake air amount control device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |