GB2293893A - Engine temperature management - Google Patents
Engine temperature management Download PDFInfo
- Publication number
- GB2293893A GB2293893A GB9420062A GB9420062A GB2293893A GB 2293893 A GB2293893 A GB 2293893A GB 9420062 A GB9420062 A GB 9420062A GB 9420062 A GB9420062 A GB 9420062A GB 2293893 A GB2293893 A GB 2293893A
- Authority
- GB
- United Kingdom
- Prior art keywords
- temperature
- engine
- combustion
- coolant
- pressure
- 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- Withdrawn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
- 238000002485 combustion reaction Methods 0.000 claims abstract description 41
- 239000002826 coolant Substances 0.000 claims abstract description 25
- 239000012530 fluid Substances 0.000 claims description 5
- 230000001105 regulatory effect Effects 0.000 abstract description 2
- 238000000034 method Methods 0.000 description 7
- 238000007726 management method Methods 0.000 description 6
- 239000000446 fuel Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 229930195733 hydrocarbon Natural products 0.000 description 4
- 150000002430 hydrocarbons Chemical class 0.000 description 4
- 239000004215 Carbon black (E152) Substances 0.000 description 3
- 239000000567 combustion gas Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000003795 desorption Methods 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000012886 linear function Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D35/00—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for
- F02D35/02—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for on interior conditions
- F02D35/023—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for on interior conditions by determining the cylinder pressure
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
- F01P7/00—Controlling of coolant flow
- F01P7/14—Controlling of coolant flow the coolant being liquid
- F01P7/16—Controlling of coolant flow the coolant being liquid by thermostatic control
- F01P7/167—Controlling of coolant flow the coolant being liquid by thermostatic control by adjusting the pre-set temperature according to engine parameters, e.g. engine load, engine speed
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B77/00—Component parts, details or accessories, not otherwise provided for
- F02B77/08—Safety, indicating, or supervising devices
- F02B77/085—Safety, indicating, or supervising devices with sensors measuring combustion processes, e.g. knocking, pressure, ionization, combustion flame
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D35/00—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for
- F02D35/02—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for on interior conditions
- F02D35/025—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for on interior conditions by determining temperatures inside the cylinder, e.g. combustion temperatures
- F02D35/026—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for on interior conditions by determining temperatures inside the cylinder, e.g. combustion temperatures using an estimation
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
- F01P2023/00—Signal processing; Details thereof
- F01P2023/08—Microprocessor; Microcomputer
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
- F01P2025/00—Measuring
- F01P2025/04—Pressure
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
- F01P2025/00—Measuring
- F01P2025/60—Operating parameters
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Combined Controls Of Internal Combustion Engines (AREA)
Abstract
The flow of coolant in an ic engine is regulated 20 in accordance with the measured peak combustion pressure 12 for a cycle of the engine. Coolant flow is thus controlled to optimise the cylinder inner wall temperature for current operating conditions, the cylinder inner wall temperature being estimated using a formula linking the heat rejection per engine cycle to the measured peak combustion pressure 12 and coolant temperature 16. <IMAGE>
Description
Engine Temperature Management
The present invention relates to engine temperature management.
The conventional manner of regulating the temperature of an engine is to pass the coolant, usually water, through a thermostatic valve having a through flow cross section that increases with temperature. The thermostatic valve therefore acts, as its name implies, to maintain the same coolant temperature, regardless of the engine operating conditions.
In practice, this is not ideal because the cylinder walls have a finite thickness and thermal conductivity which results in the critical inner surface temperature being different from the coolant temperature. Under high load, when the temperature gradient is at a maximum, the inner surface temperature is significantly higher than the coolant temperature whereas under low load the temperature gradient is lower and the inner surface temperature is somewhat lower. It is essential to set the coolant temperature to allow for the highest temperature gradient and ensure that the inner surface never exceeds a safety limit. The result of this is that under low load conditions, the engine is cooler than necessary, leading to increased fuel consumption and hydrocarbon emissions.
To mitigate this problem, electronically controlled valves have been used to replace the thermostatic valve to vary the coolant flow rate with engine speed and load. The aim of these earlier proposals, in common with the present invention, is to enable higher engine temperatures under low load operation. To estimate the heat rejection, the known systems have used various operating parameter such as fuel injection quantity, air mass flow and manifold vacuum but all these give only an imprecise and indirect estimate of the heat rejection that does not follow sufficiently rapidly the changing conditions in the combustion chamber.
The present invention therefore seeks to provide an engine in which the temperature management of the coolant is capable following the changes in heat rejection per operating cycle from the combustion chambers more rapidly and with greater precision.
In accordance with the present invention, there is provided a fluid cooled internal combustion engine comprising means for measuring the peak gas pressure in each combustion cycle and means for varying the coolant flow rate in dependence upon of the measured values of peak pressure.
The invention is predicated on the realisation that the peak pressure in a combustion cycle and the heat rejected to the combustion chamber walls during the same cycle are closely related to one another and that by measurement of the peak pressure one can determine the temperature gradient in the walls of the combustion chamber and thereby estimate the more critical temperature on the inner surface of the walls.
In this way, it is possible to maximise the temperature under all operating conditions and thereby reduce hydrocarbon emissions and fuel consumption.
The improvement in fuel consumption is believed to be caused by the increase in charge temperature and resultant decrease in charge density. This has the effect of reducing the volumetric efficiency of the engine during part load operation and therefore reducing the air pumping losses.
The improvement in hydrocarbon emissions results from the lower charge density in the crevice volumes of the combustion chamber and increased oil film temperature. The higher oil temperature reduces the effect of storage of hydrocarbons by absorption and subsequent desorption.
In the preferred embodiment of the invention, the coolant flow rate is varied as a predetermined function of the prevailing coolant temperature, the measured combustion peak pressure and the engine speed.
More particularly, the engine may comprise means for measuring the combustion peak pressure and the coolant temperature, means for estimating the average heat rejection per cycle through the combustion chamber walls from the measured peak pressure, means for estimating the temperature on the inner surface of the walls of the combustion chamber from the temperature of the coolant in contact with the outer surface of the walls of the combustion chamber and the estimated heat rejection during each combustion cycle, and means for varying the coolant flow rate in such a manner as to set the inner surface temperature of the walls at a value determined by the prevailing engine speed and load.
The most precise method of determining the mean heat rejection through the combustion chamber is to analyse the pressure diagram taken from the combustion cycle to determine the instantaneous heat transfer and then integrate over the cycle. This is however very tedious and time consuming and is not practical for use outside an engine test laboratory.
Another known method is to calculate the brake mean effective pressure (BMEP) from the measured pressure diagram and correlate the BMEP, which is a measure of engine load, empirically against the mean heat rejection rate. This type of correlation is similar to those in which the engine load is estimated from manifold vacuum, air mass flow or fuel flow. These correlations are not satisfactory because engine load is more closely related to the heat generation process of the combustion cycle than to the heat rejection process.
The invention is based on the fact that the heat rejection during the combustion cycle is predominately driven by the instantaneous temperature difference between the hot combustion gases and the walls of the combustion chamber. A major proportion of the heat rejection per cycle takes place during the short time interval within the cycle when the temperature of the combustion gases is at its maximum. It is therefore reasonable to expect the mean heat rejection per cycle to be more closely related to the peak gas temperature or the peak combustion pressure.
Extensive experimental data of the heat rejection per cycle against the peak combustion pressure of each cycle has been taken for a wide selection of engine types, each covering the full range of speed and load operating conditions. All the data was found to correlate closely according to a linear function for each engine speed, which indicates that an empirical linear relationship exists between the heat rejection per cycle and the peak combustion pressure of each cycle at a fixed engine speed. Further correlation shows the heat rejection per cycle varies as a negative power of the engine speed. One can modify the empirical relationship still further to take into account the bore size and it has been possible in this way to arrive at a single empirical formula that may be applied accurately to all engines at all values of engine speed and load to calculate the heat rejection per cycle.
The discovery of such an empirical relationship, of which there is no teaching from the previously known methods, makes it practicable to implement the thermal management method of the invention. Using only empirical equations and a few calibration constants, one can arrive at a much more accurate estimation of the heat rejection per cycle than was previously possible.
Because the invention is interested only in the peak pressure per combustion cycle, it is possible to simplify the design of the pressure sensor. In particular, it is not necessary to sense the pressure continuously and process the electrical output to determine the peak pressure. One may instead mount the pressure sensor behind a one-way valve so that only the peak pressures are applied to a small volume chamber containing the pressure sensor.
It is furthermore possible to use a single sensor to sense the peak pressure in all cylinders. This may be achieved by connecting all the combustion chambers through respective one-way valves to a common chamber containing the pressure sensor and from which the pressure is slowly bled to atmosphere through a flow restrictor. Such an arrangement for sensing the peak pressures in the combustion chambers of an engine is described in our co-pending British Patent
Application No. 9413232.1.
The invention will now be described further, by way of example, with reference to the accompanying drawing which is a block diagram of an engine with a coolant management system.
An engine 10 is connected to a peak combustion pressure sensor 12, a speed sensor 14 and a coolant temperature sensor 16, all of which sensors supply input signals to a micro-computer 18 that may be the engine management computer. The signals from the sensors 12, 14 and 16 are processed in the micro-computer 18 and used to estimate the cylinder wall temperatures. Output from computer 18 is supplied to a coolant flow control valve 20 which then sets the rate of coolant flow through the engine and radiator to optimise the engine cylinder wall temperature.
The pressure sensor 12 may be the same as that described in
Patent Application No. 9413232.1 or may be comprised of any other known system for measuring combustion pressure. The other blocks in the diagram may also be conventional and do not therefore call for detailed description.
The computer 18 processes the peak pressure information in conjunction with engine speed data and stored constants using a single empirical formula to arrive at the prevailing rate of heat rejection per cycle and from it an estimate of the wall temperature of the combustion chambers. The flow rate of the coolant through an electronically controlled valve 20 is then varied by the computer 18 to optimise the cylinder wall temperature for the prevailing operating conditions.
Claims (4)
1. A fluid cooled internal combustion engine comprising means for measuring the peak gas pressure in each combustion cycle and means for varying the coolant flow rate in dependence upon of the measured values of peak pressure.
2. A fluid cooled internal combustion engine as claimed in claim 1, wherein the engine comprises means for measuring the combustion peak pressure and the coolant temperature, means for estimating the average heat rejection per cycle through the combustion chamber walls from the measured peak pressure, means for estimating the temperature on the inner surface of the walls of the combustion chamber from the temperature of the coolant in contact with the outer surface of the walls of the combustion chamber and the estimated heat rejection during each combustion cycle, and means for varying the coolant flow rate in such a manner as to set the inner surface temperature of the walls at a value determined by the prevailing engine speed and load.
3. A fluid cooled internal combustion engine as claimed in claim 1 or claim 2, wherein the means for measuring the peak pressure comprises a pressurised chamber connected to all the combustion chambers by respective one-way valves, a single pressure sensor within the pressurised chamber and a flow restrictor connected to bleed off the pressure from the pressurised chamber to the ambient atmosphere.
4. A fluid cooled internal combustion engine as claimed in any preceding claims and constructed, arranged and adapted to operate substantially as herein described with reference to and as illustrated in the accompanying drawing.
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9420062A GB2293893A (en) | 1994-10-05 | 1994-10-05 | Engine temperature management |
EP95929158A EP0784742B1 (en) | 1994-10-05 | 1995-08-18 | Engine temperature management |
DE69504858T DE69504858T2 (en) | 1994-10-05 | 1995-08-18 | TEMPERATURE CONTROL OF AN INTERNAL COMBUSTION ENGINE |
PCT/GB1995/001972 WO1996011332A1 (en) | 1994-10-05 | 1995-08-18 | Engine temperature management |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9420062A GB2293893A (en) | 1994-10-05 | 1994-10-05 | Engine temperature management |
Publications (2)
Publication Number | Publication Date |
---|---|
GB9420062D0 GB9420062D0 (en) | 1994-11-16 |
GB2293893A true GB2293893A (en) | 1996-04-10 |
Family
ID=10762368
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB9420062A Withdrawn GB2293893A (en) | 1994-10-05 | 1994-10-05 | Engine temperature management |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP0784742B1 (en) |
DE (1) | DE69504858T2 (en) |
GB (1) | GB2293893A (en) |
WO (1) | WO1996011332A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19823603A1 (en) * | 1998-05-27 | 1999-12-02 | Behr Thermot Tronik Gmbh & Co | System for controlling coolant temperature of internal combustion engine of motor vehicle |
FR2836205A1 (en) * | 2002-02-15 | 2003-08-22 | Renault | Method for determining instantaneous temperature of gas under pressure, comprises two temperature measurements within the thickness of the chamber wall and calculation using error function |
CN112814784A (en) * | 2020-12-29 | 2021-05-18 | 江苏奥畋工程科技有限公司 | Intelligent ship turbine fault diagnosis system based on complex network |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9719408B2 (en) * | 2014-08-22 | 2017-08-01 | GM Global Technology Operations LLC | System and method for engine block cooling |
US9869223B2 (en) * | 2014-08-22 | 2018-01-16 | GM Global Technology Operations LLC | Flexible engine metal warming system and method for an internal combustion engine |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS572418A (en) * | 1980-06-06 | 1982-01-07 | Nissan Motor Co Ltd | Engine temperature controller |
JPS58195035A (en) * | 1982-05-11 | 1983-11-14 | Mitsubishi Heavy Ind Ltd | Device for adjusting maximum pressure in engine cylinder for diesel engine |
JPS61138816A (en) * | 1984-12-07 | 1986-06-26 | Toyota Motor Corp | Fuel evaporation rate control system for direct-injection inernal-combustion engine |
JPS6299615A (en) * | 1985-10-24 | 1987-05-09 | Mazda Motor Corp | Engine cooling device |
GB2247745A (en) * | 1990-09-05 | 1992-03-11 | Ford Motor Co | Engine cooling system |
-
1994
- 1994-10-05 GB GB9420062A patent/GB2293893A/en not_active Withdrawn
-
1995
- 1995-08-18 WO PCT/GB1995/001972 patent/WO1996011332A1/en active IP Right Grant
- 1995-08-18 EP EP95929158A patent/EP0784742B1/en not_active Expired - Lifetime
- 1995-08-18 DE DE69504858T patent/DE69504858T2/en not_active Expired - Fee Related
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19823603A1 (en) * | 1998-05-27 | 1999-12-02 | Behr Thermot Tronik Gmbh & Co | System for controlling coolant temperature of internal combustion engine of motor vehicle |
FR2836205A1 (en) * | 2002-02-15 | 2003-08-22 | Renault | Method for determining instantaneous temperature of gas under pressure, comprises two temperature measurements within the thickness of the chamber wall and calculation using error function |
CN112814784A (en) * | 2020-12-29 | 2021-05-18 | 江苏奥畋工程科技有限公司 | Intelligent ship turbine fault diagnosis system based on complex network |
Also Published As
Publication number | Publication date |
---|---|
DE69504858T2 (en) | 1999-02-11 |
DE69504858D1 (en) | 1998-10-22 |
WO1996011332A1 (en) | 1996-04-18 |
GB9420062D0 (en) | 1994-11-16 |
EP0784742A1 (en) | 1997-07-23 |
EP0784742B1 (en) | 1998-09-16 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |