2005-01-1378

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2005-01-1378

Innovative Engine Cooling Systems Comparison

Ngy-Srun Ap and Michelle TarquisVALEO Engine Cooling

Reprinted From: Thermal Management Systems, Modeling, and Components(SP-1945)

2005 SAE World CongressDetroit, MichiganApril 11-14, 2005

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ABSTRACT

In order firstly to reduce weight, packaging and cost of engine cooling system and secondly to reduce fuel consumption and pollutants in the exhaust we have seen, over the last twenty years, several innovative engine cooling system offers. These innovative engines cooling were:

Nucleate boiling engine cooling, THEMIS cooling system, Precision cooling

system, Intelligent cooling System, , CoolMaster UltimateCooling

For each cooling system several vehicles were tested in the climatic wind tunnel, on road in real conditions and on fuel consumption and pollution facilities. The comparison of these innovative engine cooling systems will be presented in this paper, in terms of:

System weight, packaging and cost, Fuel consumption and pollutants in the

exhaust, Thermal comfort, Heat performance of engine cooling system.

INTRODUCTION

Adiabatic engine excepted, the conventional ICE always needs an engine cooling system. In order firstly to reduce weight, packaging and cost of these systems and secondly to reduce fuel consumption and pollutants in the exhaust we have seen, during the last twenty years, several innovative engine cooling systems offers. Some of them are more or less interesting in terms of their breakthrough levels. These innovative engines cooling were:

Nucleate boiling engine cooling: stagnant boiling or convective boiling in the engine [see references 1 to 4] adopted and tested by different car manufacturers,

THEMIS system [references 6 to 8], Precision system, Intelligent System: coolant flow rate and coolant temperature control are ensured by an electric water pump and an electric water valve instead of a conventional mechanical driving

pump and of a conventional thermostat respectively,

CoolMaster: coolant temperature control is ensured by an electric water valve instead of an electric thermostat or the conventional thermostat,

UltimateCooling: water is the only one coolant for all of engine fluids [reference 5].

These different innovative engine cooling systems should be validated according to the engine cooling specifications. Several vehicles were tested in the climatic wind tunnel, on road in real conditions and on fuel consumption and pollution facilities. The comparisons of these innovative engine cooling systems will be presented in this paper, particularly the first four systems above, in terms of:

System weight, packaging and cost, Fuel consumption and pollutants in the exhaust, Thermal comfort, Heat performance of engine cooling system.

There are other innovative engine cooling systems:

Split Cooling: two separate flow rate loops in the cylinder head and cylinder bloc. This concept is being introduced to the market right now by some car manufacturers,

Reverse cooling: engine coolant inlet on the cylinder head instead of cylinder bloc and radiator coolant inlet at the bottom instead of the top of radiator. According to our tests effected in the climatic wind tunnel, there were no big differences between this system and the conventional system,

Cooling jets: coolant jet directly on the inter-valve of cylinder head [reference 9]. The total coolant flow rate through the engine could be reduced to 40 L/mn. Cylinder head has to be modified in order to install the coolant injection system. System cost should be completed.

2005-01-1378

Innovative Engine Cooling Systems Comparison

Ngy-Srun Ap and Michelle TarquisVALEO Engine Cooling

Copyright 2005 SAE International

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NUCLEATE BOILING ENGINE COOLING SYSTEM

There are two coolant architectures for nucleate boiling engine cooling:

partially filled coolant architecture: there is coolant in the cylinder bloc and the cylinder head and all the rest of the coolant circuit remains empty. This coolant architecture was adopted and studied by two car manufacturers (Nissan and BMW).

Completely filled coolant architecture: there is coolant in the whole coolant circuit. That means the coolant circuit is practically the same as the conventional engine cooling today. This is our coolant architecture and was adopted and studied by two car manufacturers (Renault and VW).

WORKING PRINCIPLE

This concept (called REROM) is developed in the references 1 to 4 by using a small electric water pump of 30 to 80 W, instead of the conventional driven pump of 1 to 2 kW. This small electric water pump provides a flow rate of approximately 1 000 to 1 500 l/h depending on the pressure drop of coolant circuit. Coolant temperature is ensured by a conventional wax thermostat. Other features of this concept are:

low relative pressure in the coolant circuit ; only 0.2 bar instead of 1.5 bar for example,

maximum coolant temperature of 115C, conventional engine cooling for low and medium

engine load (until 140 km/h of vehicle speeds), nucleate boiling engine cooling for high engine load

(max. speeds and hill climbing).

Coolant architecture

Practically the same components as the conventional engine cooling have been used, except:

a small electric water pump of 50W instead of a conventional mechanical driven pump,

a special expansion tank equipped with a membrane inside (see figure 3) allowing to absorb the coolant coming from the engine and the radiator when the engine works under nucleate boiling (high speeds > 140 km/h or hill climbing conditions),

only one small diameter of hoses. That means same heater core hoses have been used for the whole coolant circuit and most importantly these hoses have not reinforced due to the very low pressure of coolant circuit (max. pressure of

0.2 bar instead of 1 to 2 bars for the conventional coolant circuit).

Figure 1: Example of coolant architecture

Figure 2: Example of 3D coolant architecture

Figure 3: Expansion tank for Renault Twingo

MAIN TEST RESULTS

Several vehicles (see table 1 below) have been equipped with this system and tested in the climatic wind tunnel and on road under real conditions.

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Vehicle Engine Displacement Max power(Liter) (HP)

Renault Twingo Gasoline 1,2 60Renault Clio Gasoline 1,4 80Renault 19 Diesel ID 1,9 70VW GOLF Diesel TDI 1,9 90VW Passat Gasoline 1,8 90Seat Arosa Diesel SDI 1,7 60

Table 1: Test vehicles

Engine cooling performance

Compared to the conventional cooling system, the REROM system exhibits the following features :

the cylinder head temperature is approximately 5 to 10C hotter. These results confirm the test bench results. The values remain below the critical limit (200C). A modification of the cooling circuit in the cylinder head is therefore not needed.

the cooling flow rate is 1300 to 1400 l/h instead of 4300 to 5 300 l/h ( 4 times less) for the Renault Twingo engine and 1500 l/h instead of 8000 to 8700 l/h (5.5 to 6 times less) for the Seat Arosa engine.

the circuit pressure is around 100 mbar instead of 650 mbar for the gasoline engine and less than 100 mbar instead of 800 mbar for the diesel engine.

the oil sump temperature is increased by approximately 2 to 3 C.

Even if the cylinder head, coolant and oil sump temperatures are higher than the conventional cooling system, the cooling performance of the REROM system is still good according to the engine cooling specifications.

Figure 4: Engine cooling performance at 50 km/h, hill climbing, Ta = 30 C for Renault Twingo

Thermal comfort performance

The heater core air temperature and the passenger compartment air temperature are almost the same for the two systems except at idle. During idling, the heater core air temperature is increased by approximately 15 to

20C. The increase is 5 C on the passenger compartment air temperature (see figure 5). This increase is directly related to the REROM high flow rate (1 300 l/h) through the heater core, versus the conventional system (300 l/h) at idle. This is the counterpart of the high heater core performance. The heat given to the air is extracted from the coolant and the engine.

Figure 5 : Thermal comfort at 18 C for Renault Twingo

Fuel consumption and Pollution reduction

Fuel consumption and pollution measurement according to MVEG cycle shows (figures 6 and 7):

2 to 3% fuel consumption reduction, 10% CO and 3% HC emissions reduction.

Figure 6: Fuel consumption comparison results for Renault Twingo and Seat Arosa

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Figure 7: Pollution test results for Renault Twingo and Seat Arosa

BENEFITS

Compared to the conventional cooling system and based on the Renault Twingo and the Seat Arosa SDI, nucleate boiling system exhibits the following results :

good performance of engine cooling. Even if the cylinder head, the coolant and the oil sump temperatures are slightly higher, they still fall within the engine cooling specifications,

slightly better (+2 C) for passenger compartment heating, but really better at idle (+5C),

10 to 15 % cost reduction, 20 to 25 % weight reduction, 20 to 25 % coolant volume reduction, 2 to 3% fuel consumption reduction (MVEG cycle) 10% CO and 3% HC emissions reduction (MVEG

cycle)

DISADVANTAGES AND CONSEQUENCES

This is a new concept of engine cooling, particularly in the cylinder head. Several tests like durability, reliability, aging test, should be effected on a minimum vehicle fleet.

THEMIS SYSTEM

WORKING PRINCIPLE

Our THEermal Management Intelligent System THEMIS system [see references 6 to 8] or Precision system from Visteon company or Intelligent System from Dana company has the following main characteristics: coolant flow rate and coolant temperature control are ensured by an electric water pump and an electric water valve instead of a conventional mechanical driving pump and of a conventional thermostat respectively. That means the mechanical driving pump has been replaced

by an electric water pump of 200 to 600 W depending on the engine size and the conventional wax thermostat has been replaced by an electric water valve. An appropriate control strategy has been built allowing to drive the three actuators which are the electric water pump, electric water valve and electric fan with feedback from the coolant temperature sensor.

There is an other similar concept, called CoolMaster. This is a THEMIS with mechanical water pump instead of main electric water pump. CoolMaster could have an additional small electric water pump for auxiliary functions like cab heating booster, post cooling, cab heating after engine is off,

Coolant architecture of THEMIS

Figure 8 below shows the coolant architecture. This architecture has been used for different vehicles (see table 2).

Figure 8: Coolant architecture of THEMIS

The THEMIS control strategy is divided in to 3 main parts, as described in figure 9. Using usual sensors and engine management information, the first part is the steady state model. Steady state engine heat release, radiator efficiency and coolant temperature are then entering the second part, the dynamic models of engine heat release and cooling radiator efficiency. Multiple data are then forwarded to the third part, the control strategy.

Figure 9 : Synoptic of THEMIS strategy control

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Coolant architecture of CoolMaster

Coolant architecture of CoolMaster is similar to THEMIS one, using the mechanical water pump instead of an electric water pump. A small electric water pump of 20 to 30 W has been mounted on the heater core hoses in order to boost their heat performance.

Figure 10: Coolant architecture of CoolMaster

MAIN TEST RESULTS

Several vehicles (see table 2 below) have been equipped with this system and tested in the climatic wind tunnel and on road in real conditions. Contrary to the above concept, THEMIS system works practically in the same way as the conventional engine cooling with mechanical driving pump for the worst conditions like max speeds and hill climbing. There is no nucleate boiling in the engine even if the main coolant flow rate is 30 to 50 % less.

Vehicle Engine Displacement(Liter)

VOLVO S80 Gasoline 2,4Mercedes A class Gasoline 1,6Renault Megane Gasoline 1,4

Chrysler Minivan V6 Gasoline 3,8OPEL Vectra Diesel TDI 1,2

Table 2: Test vehicles for THEMISsystem and/or CoolMaster

Thermal comfort performance

Benefits on cabin comfort are obtained by a correct management of coolant flow rate inside the cooling system. By increasing the coolant flow rate in the heater core, the heating performance is enhanced. Like REROM (see above) system, thermal comfort at the idle condition could be reached up to 4 or 5 C improvement versus the baseline.

Figure 11: Heating boost during idle for Volvo S80

Thermal comfort after engine off

The control of the coolant flow that conveys heat from the engine to the cabin allows us to keep high level cabin temperature under very cold winter conditions, even after the engine has stopped. With low coolant flow rate and low blower speeds through the heater core, thermal comfort remains practically the same when the engine is ON (see figure 12) even 30 minutes after the engine is OFF.

Fugure 12: Cab heating after engine off for Volvo S80 at Ta = - 20C

Post cooling

A precise coolant flow rate control has evidenced to affect the engine protection positively. Heat soak and boiling can be prevented after the engine has been stopped by controlling the operation of electric water pump and electric fan. With this strategy control, coolant temperature drops down quickly (see figure 13). This after running function allows the extensive use of high temperature running at city driving, low and medium speeds (partial engine load).

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Figure 13: Post cooling after engine stop for Volvo S80

Fuel consumption and Pollution

After extensive development and applications on different engines and cars (see table 2), a reduction of 5% fuel consumption, 20% CO and 10% HC tail pipe emissions can be announced as average gain. The fuel consumption reduction is due to the faster and higher temperature level of average temperature during the test cycle:

110 C instead of 90 C for coolant temperature (figure 14).

150 C instead of 120 C for cylinder head temperature (figure 15).

10 to 20 C warmer for oil sump temperature. These possible temperature levels are due to the very good response time (3 to 5 times quicker) and accuracy (+/- 2 C) of electric water valve versus the conventional wax thermostat heated or not (+/- 5 to 7 C). Moreover, zero coolant flow strategy has a positive effect. On some applications no less than 5% fuel consumption saving has been measured on the high speed part of the EUDC cycle.

Figure 14: Coolant temperature during fuel consumption tests (MVEG cycle)

Figure 15: Cylinder head temperature during fuel consumption tests (MVEG cycle)

BENEFITS

Compared to the conventional cooling system, THEMIS system exhibits the following results :

Fuel consumption reduction up to 5% depending on the size and type of engine,

Pollution reduction up to 20% for CO and up to 10% for HC,

Good response time on coolant and cylinder head temperature due to the very good response of electric water valve instead of wax thermostat,

Cab heating booster at idle, up to + 5 C improvement of thermal comfort,

Cab heating after engine is off, thermal comfort could be maintained up to 30 minutes after engine is OFF,

Good post heating.


This system needs two new main components: an electric water pump and an electric water valve. There is an additional cost due to these two components (see table 3 below).

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achieved % 25 75 100 100

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75

* Compared to a traditional cooling loop with wax thermostat Table 3 : System cost comparison

ULTIMATECOOLING SYSTEM

The detail of this UltimateCooling system concept has been showed in the reference [5].

WORKING PRINCIPLE

UltimateCooling has been achieved by using engine coolant exclusively to cool all the various fluids in the vehicle, i.e. air, refrigerant, oil, exhaust gas and fuel. Thus, the air to air CAC was replaced by an air to water (coolant) CAC (WCAC) and the refrigerant to air A/C condenser by a refrigerant to water (coolant) A/C condenser (WCDS). These new heat exchangers were located close to the heat source, resulting in shorter hoses. As a result, the air, refrigerant and coolant hoses architecture became all the more compact. The cooling radiator in our project is the only heat exchanger that remains in the forefront of the vehicle. This could reduce repair cost significantly after a small impact in city driving, since only one cooling radiator would have to be replaced instead of the combination of CAC, A/C condenser and other heat exchangers. This cooling radiator is a multi-temperature radiator in which the amount of high temperature and low temperature water can be modulated, according to engine operating conditions, engine load priorities and the thermal comfort required.

Figure 16: Todays design of cooling system

Figure 17: UltimateCooling design

Coolant architecture

Figure 18: Coolant architecture of UltimateCooling for Mercedes C class 220 CDI

Figure 18 above shows an example of coolant architecture. There are only two radiators (HT and LT) at the front end. The HT radiator ensures the engine cooling, oil cooling and EGR cooling. The LT radiator ensures the water charge air cooling (WCAC), water condenser (WCDS) and fuel cooler (FC). HT and LT could be integrated in one multi-temperature radiator. Thus there will be only one radiator located at the front end. LT loop needs a small electric water pump of 50 Watts in order to ensure the heat performance of WCAC, WCDS and FC.

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MAIN TEST RESULTS

A turbo diesel vehicle Mercedes C class 220CDI, has been equipped with this system and tested in the climatic wind tunnel and on road in the real conditions.

Packaging balance

Figure 19: Packaging balance on Mercedes C class 220CDI

Packaging balance, based on Mercedes C class 220 CDI has been carried out (figure 19). All calculations are based on the last components that the general good performances have been obtained (see chapter below). Compared to the baseline equipped with the conventional cooling system, UltimateCooling has the following advantages:

10 liters reduction of cooling module at the front end by moving WCAC, WCDS to the underhood.

6 liters reduction of overall thermal system volume due to the reduction of air manifold hoses length, packaging of WCAC (integrated on the top of engine) and packaging of WCDS.

4 liters volume increases in the underhood because WCAC and WCDS are now located in the engine compartment.

Charger air cooling (CAC)performance

The performance of CAC for the conventional system and WCAC for UltimateCooling has been obtained by the climatic wind tunnel tests with A/C on and off according to the worst conditions of engine:

hill climbing of 10 % grade with trailer and Ta of 30 C,

hill climbing of 60 % grade without trailer and Ta of 40 C,

full load of engine at flat road, 200 km/h and Ta of 35 C.

Table 4: CAC performance comparison for A/C on

Table 4 above shows that air CAC temperature is 4 to 10 C better than baseline if A/C is on.

Table 5: CAC performance comparison for A/C off

Table 5 above shows that air CAC temperature is 13 to 20 C better than baseline if A/C is off.

Thermal comfort performance: A/C system

Figure 20: Cab temperature during cool down test under Ta = 45 C and solar radiation of 1000 W/m

A/C performance of UltimateCooling system is similar to baseline system.

Engine cooling performance

For different worst conditions of engine (see WCAC test conditions above), the engine cooling performance of UltimateCooling system is similar to the baseline system (table 6).

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10% Grade with Trailer, 30C 6% Grade without Trailer, 40 C 40 km/h, Gear 2, A/C ON 90 km/h, Gear 3, A/C ON

Baseline Ultimate Baseline Ultimate Coolant T (C) 119 119 117 114

Oil Sump T (C) 140 141 136 133

180 km/h Flat Road 35C 200 km/h Full Load 35C

Baseline Ultimate Baseline Ultimate Coolant T (C) 106 102 110 110

Oil Sump T(C) 125 123 127 129

A/C ON A/C ON

Table 6: Coolant and Oil sump temperature comparison

Fuel consumption

The Mercedes C class 220CDI has been equipped with the UltimateCooling system and tested on the fuel consumption facility according to the MVEG cycle under ambient temperature of 28 and 35 C. Two test conditions of A/C system have been effected:

Condition 1: A/C max and blower max, Condition 2: A/C with set temperature of 22 C

and blower at n4 position.

Compared to the baseline system, UltimateCooling has fuel consumption:

up to 6% for condition 1 at Ta = 28 C and cold start of engine,

similar for condition 1 at Ta = 28 C with warm engine,

similar for other test conditions.

BENEFITS

Compared to the conventional cooling system and based on Mercedes C class 220CDI, UltimateCooling system exhibits the following results :

Packaging reduction in Front End by -10 Liters (- 40%),

Danner crash repair cost reduction, Green House Gas benefit (750g of R134a ~

1000 kg of CO), Better WCAC performance (4 to 10 C better if

A/C is ON, and 13 to 20 C better if A/C is OFF, its very

interesting for downsizing of ICE, Better engine performances and dynamic

response (turbo lag), Mutualization of thermal exchange potential : all

heat exchangers being cooled down by the same fluid, A/C, Charge Air and Engine cooling operates by sharing power depending on the vehicle speed conditions,

Could supply low temperature coolant to other fluids : fuel cooler, EGR cooler, oil cooler,

electronic cooler and electric power-train cooler for HEV, FCEV,

Less high cost hoses: A/C, OC, CAC, Cross-line component standardisation : WCAC,

WCDS


Based on Mercedes C class 220CDI, there is an additional weight of 2 to 2.5 kg due to the additional coolant volume in the LT loop for WCAC and WCDS.

ENGINE COOLING SYSTEMS COMPARISON

The four engine cooling systems: REROM, THEMIS, CoolMaster and UltimateCooling present the different benefits and disadvantages in terms of fuel consumption, pollution, global weight and packaging, cooling module weight and packaging at the front end, thermal comfort performance, engine performance and finally the system cost. Tables 7a to 7c below, show these engine cooling systems comparison versus the baseline equipped with the conventional system today, that means with mechanical driving pump, wax thermostat, air CAC and air CDS. However these four innovative systems have the different specificities in terms of vehicle ranges and engine types (see figure 21), that is to say:

REROM system is a very advantageous system application for the small and compact vehicles equipped with the small gasoline or small diesel engine.

THEMIS and CoolMaster system are a very good system for medium and high vehicle ranges equipped with the gasoline engine (diesel engine has to be confirmed).

UltimateCooling system is preferable to medium and high vehicle range equipped with the turbo diesel engine and also to high vehicle range equipped with a big turbo gasoline engine.

Figure 21: Engine cooling system application versus vehicle range

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Engine Fuel Pollution Post EngineCooling consumption cooling PerformanceSystemREROM +++ +++ +++ 0

THEMIS +++ +++ +++ 0CoolMaster ++ ++ +++ (*) 0

UltimateCooling + ++(**) + (**) +++ (*) +++

(*): with small electric water pump (**): MVEG cycle with A/C ON at Ta = 28 C +++ = very good, --- = very bad, 0 = same Table 7a: Engine cooling systems comparison

Engine CoolingSystem

Packaging Weight Packaging WeightREROM ++ ++ + +

THEMIS - - 0 0CoolMaster 0 0 0 0

UltimateCooling ++ - +++ +++

systempackaging of cooling

Global weight & Cooling module weight & packaging

(*): with small electric water pump (**): MVEG cycle with A/C ON at Ta = 28 C +++ = very good, --- = very bad, 0 = same Table 7b: Engine cooling systems comparison

Engine Cooling Engine Engine A/CSystem on off performance

Cab heating Cab heatingREROM +++ +++ 0

THEMIS +++ +++ 0CoolMaster +++ (*) +++ (*) 0

UltimateCooling +++ (*) +++ (*) + (**)

Thermal comfort

(*): with small electric water pump (**): MVEG cycle with A/C ON at Ta = 28 C +++ = very good, --- = very bad, 0 = same Table 7c: Engine cooling systems comparison

Engine Fuel SystemCooling consumption costSystem MVEG cycleREROM up to - 3% "- 15 to - 20 "

THEMIS up to - 5% "+ 55 to + 75 "CoolMaster(*) up to - 3% " + 35 "CoolMaster up to - 3% "+ 25 "

MWP& Heated Th. up to - 2% "+ 15 "UltimateCooling up to - 6%(**) 0

(*): with small electric water pump (**): MVEG cycle with A/C ON at Ta = 28 C Table 7d: Engine cooling systems comparison

FUEL CONSUMPTION AND POLLUTION

Thanks to the electric water pump or electric water valve, zero coolant flow rate at the engine cold start could be used. Thus metal temperature, exhaust gas, oil sump and coolant rise quickly and lead to fuel consumption and pollution reduction. These are REROM, THEMIS and CoolMaster systems.

POST COOLING

Thanks to the main electric water pump for REROM and THEMIS system, and the additional electric water pump for CoolMaster and UltimateCooling, post cooling could be solved. With the complementary of electric fan the coolant temperature drops down quickly.

ENGINE PERFORMANCE

Due to the very good performance of WCAC for UltimateCooling system, air manifold temperature is lower than the baseline. Good performance of engine has been obtained, particularly the dynamic response. These good results represent a large potential for downsizing of turbo diesel engine.

GLOBAL WEIGHT AND PACKAGING

Due to the system concept by using nucleate boiling in the engine, REROM concept presents real advantages of global weight and packaging reduction: coolant volume reduction (- 25%), hoses (same small diameter of heater core hoses for all coolant circuit) and small water boxes of radiators. UltimateCooling also has a slight advantage.

PACKAGING OF COOLING MODULE

Concerning the cooling module at the front end UltimateCooling has a very important packaging reduction by moving the CDS, CAC, OC and TOC to the inside of under-hood. This advantage is very beneficial in terms of front end design in order to satisfy the pedestrian crash norms in the near future.

THERMAL COMFORT

Cab heating when the engine is ON

Thanks to the main electric water pump for REROM and THEMIS system, and the additional electric water pump for CoolMaster and UltimateCooling, thermal comfort could be improved, particularly at the idle.

Cab heating when the engine is OFF

When the engine is OFF the 4 systems above could maintain the thermal comfort during at least 30 minutes under outside temperature of - 20 C. This benefit is

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possible by managing the coolant flow rate and the blower through the HVAC.

A/C performance

Compared to the baseline vehicle, the 4 systems have almost the same A/C performance. However, due to the thermal inertia of water (coolant), UltimateCooling has a little advantage at the cold start of engine. The electric fan operates later than usual and could represent a benefit for fuel consumption tests, particularly for the official MVEG cycle. Concerning THEMIS and CoolMaster, A/C performance (thermal comfort) is slightly better due to the EWV operation by suppressing the hot coolant through the heater core during hot summer driving.

System cost

Table 7d above shows that the most economical system is the nucleate boiling system called REROM due to low cost of hoses particularly. UltimateCooling has a system cost similar to the baseline. THEMIS and CoolMaster system have 25 to 75 over cost depending on the THEMIS level applications; that means, compare to the conventional engine cooling system with MWP and wax thermostat:

CoolMaster without small EWP has 25 over cost,

CoolMaster with small EWP has about 35 more,

THEMIS has about 55 to 75 more.

CONCLUSION

Valeo has a complete innovative engine cooling system with high breakthrough levels. These systems have been validated in the climatic wind tunnel, road tests under real conditions, including hot missions in the south of Europe and cold missions near the polar circle. These systems are available for car manufacturers wishing to improve their engine cooling systems. Good performance of thermal comfort was obtained at idle during engine ON and during engine OFF.

Our recommendations are:

THEMIS or CoolMaster could be used if the fuel consumption and pollutions reduction are really the main target. Also its very good for the medium and high vehicle range equipped with the gasoline engine.

REROM could be a good system in order to reduce fuel consumption, pollution and system cost. Its very beneficial for low vehicle range equipped with small gasoline and small diesel engine.

UltimateCooling is a good system in order to reduce the packaging of cooling module at the front end. Its an ideal system for high vehicle range equipped with the turbo diesel or turbo gasoline engine.

Of course the combination of the two innovative systems is possible, for example, UltimateCooling with THEMIS or CoolMaster allows cooling module reduction at the front end, thermal comfort improvement, post cooling improvement, fuel consumption and pollution reduction.

ACKNOWLEDGMENTS

The authors acknowledge and give thanks to Michel FORISSIER, R&D Director of Valeo Engine Cooling, for his assistance and his advice and special thanks to vehicle tests team and components team for their very interesting work and their participation during the preparation of this paper.

REFERENCES

1. N.S.AP, A.MAIRE, P.POROT, P.MENEGAZZI, F.SOUIDI, C.LE DEVEHAT, D.GODEAU, P.OLIVIER, J.B.VINOT, and G.VINCENS

New Components Development for New Engine Cooling System

VTMS4 1999 paper n C543/04/99 London 2. N.S.AP and N.C.GOLM, New Concept of

Engine Cooling System (Newcool) , VTMS3 Congress, paper n971775 1997 Indianapolis

3. P.A.POROT, P.MENEGAZZI and N.S.AP, Understanding and Improving Evaporative Engine Cooling at high load, high speed by Engine Tests and 3D Calculations , VTMS3 Congress, paper n 971792 1997 Indianapolis.

4. N.S.AP and M.PRETSCHER, Nucleate Boiling Engine Cooling System - Vehicle Study , VTMS1 Congress, paper n931132, 1993, Columbus

5. N.S.AP P.GUERRERO P.JOUANNY M.POTIER J.GENOIST J.L.THUEZ Ultimate Cooling New Concept Of Cooling System by using the same Coolant to Cool all of Vehicle Fluids, VTMS6 congress 2003 Brighton

6. P.Y.GEELS Advanced Control strategy for modern engine cooling thermal systems, and effect on CO and pollutant reduction, VTMS6 congress 2003 Brighton

7. M.CHANFREAU B.GESSIER A.FARK P.Y.GEELS The need for an Electrical Water Valve in a THErmal Management IntelligentSystem (THEMIS) SAE n2003-01-0274

8. H.COUETOUX D.GENTILE Cooling System Control in Automotive Engines, SAE paper n 920788

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9. A.VAGENAS J.G.HAWLEY C.J.BRACE M.C.WARD On Vehicle Controllable Cooling Jets SAE paper n 2004-01-0049

CONTACT

Ngy-Srun AP Dr. Ing. from Pierre & Marie CURIE University (Paris - France) and Senior Expert of Engine Cooling System in VALEO Engine Cooling company, 8 rue Louis Lormand 78321 La Verriere Cedex FRANCE Email: [email protected]

DEFINITIONS, ACRONYMS, ABBREVIATIONS

A/C: Air Conditioning CAC: Charge Air Cooler WCAC: Water Charge Air Cooler CDS: Condenser WCDS: Water Condenser EGR: Exhaust Gas Recirculation EWP: Electric water pump FCEV: Fuel Cell Electric Vehicle HEV: Hybrid Electric Vehicle ICE: Internal Combustion Engine LT, HT: Low Temperature, High Temperature MVEG: European cycle for fuel consumption and pollution test MWP: Mechanical water pump OC: Oil Cooler Ta: Ambient temperature TOC: Transmission Oil Cooler REROM: Nucleate Boiling Engine Cooling system THEMIS: THEermal Management Intelligent System CoolMaster: THEMIS with mechanical water pump instead of main electric water pump. It could be with or without small electric water pump UltimateCooling: All engine fluids cooled by water

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2005-01-1378