DelphiEngine test bench calibration methodology for Delphi Diesel common rail system.docx

1、DelphiEngine test bench calibration methodology for Delphi Diesel common rail system Engine test bench calibration methodology for Delphi Diesel common rail systemCONTENTS1.PurposeThis document proposes engine optimisation methodology on engine test bench from the beginning of the project to the sta

2、rt of the production.Optimizing engines settings on a test bench is a compulsory step in a project. It is used to define the first set of calibration in order to run engine properly. Then, to choose hydraulic system design which reaches performances and emissions targets. After that, it allows to de

3、fine optimum settings for a large amount of calibrations and to validate system functionalities on the project. Finally, Test bench will be used to quantify scattering and to demonstrate engine capability for extreme cases.2.ScopeThis document applies to bench test for engines equipped with Delphi c

4、ommon rail system.3.DefinitionsVI : Valve InBSFC : Brake Specific Fuel ConsumptionTDC : Top Dead CenterPWM : Pulse Width ModulationI/D : Inner DiameterECU : Electronic Control UnitHP : High PressureI2C : Individual Injector CharacteristicAPC : Accelerometer pilot controlERPM : Engine Revolution Per

5、MinuteAPV : Application Programmable VariableAPM : Application Programmable Map4.Test cell definition and engine checking4.1. InstrumentThe test cell should include all the necessary instruments for performance test, and emission test if needed. Generally below instruments are required in a test cel

6、l._dynamometer and control unit_fuel balancer with reasonable accuracy_fuel cooler_cylinder pressure measurement equipment _temperature sensor to measure the exhaust temperature for each cylinder_air filter and flow meter_intercooler_temperature sensors temperature sensors before and after intercool

7、er, exhaust temperature sensor, coolant temperature sensor, oil temperature sensor are necessary to monitor the engine status and keep the engine run in safe conditionsSensors to monitor the fuel temperature before pump inlet, fuel temperatures for injector return and pump return are optional and wh

8、ich will help to monitor the low pressure system._pressure sensors exhaust pressures before and after turbo, oil pressure, air pressures before and after intercooler_emission instrument if emission measurement is required_Steady voltage supply to power ECU; 10-16 voltage is acceptable _Atmosphere me

9、ter and humidity meter 4.2 Low pressure system4.2.1 Circuit for test cellThe pipework and fittings to be minimum 8 mm I/DThe pipework that is in contact with fuel should not contain copper or zincThe recommended generic configuration of the low pressure circuit for a test cell is described in the fo

10、llowing diagram:FUEL COOLER(IF REQD)4.2.2. Pressure ConditionsThe depression at the HP pump inlet (measured 50 mm from the pump inlet) must be above -400 mbar in relation to the atmospheric pressure. If this level is reached, STOP TEST and investigate cause.The pressure at the HP pump return (measur

11、ed 50 mm from the venturi outlet) must be below 300 mbar above the atmospheric pressure. These limitations are generic, specific limitations for each application will be provided in system objective specification.4.2.3Temperature ConditionsThe fuel temperature should be kept as 40-45 degree C at nor

12、mal running conditions.For the hot test, the temperature at pump inlet shall remain below 85C (Peak temperature of 90C can be accepted during 30 seconds when running). The low pressure circuit must allow the additional heat which comes mainly from the leak return of the injectors, to be dissipated.

13、This temperature could be as high as 110 Deg C at high engine loads.If the temperature differential across the HP pump, INLET to RETURN exceeds 50 deg C, STOP TEST and investigate cause.These limitations are generic, specific limitation for each application will be provided in system objective speci

14、fication.4.2.4Filter Change IntervalThe filter element should be changed after 200 hours of engine running. This limitation is generic, specific limitation for each application will be provided in system objective specification.See also filter team recommendation of the filter analysis.4.2.5Water se

15、dimentorCheck and empty if needed. Same interval as filter change4.3Air inlet and exhaust system- monitor pressure drop across intercooler if applicable- monitor back pressure 4.4Electrical system 4.4.1. Battery VoltageThe system ensures normal function for battery voltages at the ECU supply pin con

16、nectors between 10 to 16V. The voltage should be kept steady to guarantee the FIE system work properly. If the voltage is not at normal condition, some recovery actions need to be taken into account to put back the voltage to normal steady voltage level.The system can operate for a maximum of 1hour

17、between 16V and 18V at ECU supply pin, and the function may be deteriorated. During jump start (between 18V and 24V at ECU supply pin), the system can meet at least the functional requirement relevant for the start of vehicle, the over-voltage (between 18V and 24V at ECU supply pin) time shall be le

18、ss than 1 minute with ambient temperature less than 20C.4.4.2. Power supply requirementsThe power supply connections should have minimum DC resistance, ideally 40m Ohms total.In the case of dynamometer installations the power supply unit (PSU) should be chosen to manage the peak current requirement,

19、 ie a minimum of 25A. Ideally the PSU should be of the switch-mode type as this is better suited to transient demand changes. The supply should be located as close as possible to the ECU (1.5m) to minimise volt drop. 4.5 Engine checking before first startAn engine start attempt should only be made w

20、ith:_an adequate fuel supply system._a fully assembled high pressure fuel system_all the sensors connected_the key switch ON to make the ECU power on, but no start_all injector correction data (C2I) entered into the ECU._fault list be checked and all faults be cleared before starting the engine.Afte

21、r the first start of the engine, (either a new engine or after dismantling of the fuel system), the engine should be stopped after a period of between 1 and 5 minutes running at idle to check for fuel leaks. A visual ONLY inspection should be made of the low and high pressure system.5 Software relea

22、seDelphi will release the software at the beginning of a new application. The level of this software will be defined by the EMS team and will depend on the system function definition.6 System limits definitionBefore any full load tests, engine limits and the system limits should be defined to guaran

23、tee safe operation.6.1. PurposeThis subject describes the system limits that should be taken into account when an application is carried out.6.2. Engine limitsThe engine limits must be known before starting an engine on a test bench.The most important values to know are:_ the maximal cylinder pressu

24、re, _ the maximal engine speed, _ the maximal temperature before turbine, _ the maximal intake air temperature after the turbocharger. Note: all these items are customers responsibilities. In order to monitor the cylinder pressure, customer needs to machine a specific cylinder head to install the cy

25、linder pressure gauge.Exceeding these limits could damage the engine. Some automated tests benches are able to look after user-defined limits.The maximal fuel demand should be defined before running the engine on a test bench, to prevent bring a too big injection, which could make the engine exceed

26、the max exhaust temperature and cylinder pressure limits and damage the engine. The timings should also be considered: its important to estimate the timings limits for the multiple injections, which could cause the max exhaust temperature and cylinder pressure.6.3. Fuel System LimitsTo guarantee the

27、 system operation, some limits must be taken into account.6.3.1. Fuel characteristics/customers responsibilityThe common rail system is to be used with EN590 fuels, or EMC5 (ie: EN590 + 5% of ester). If others fuels, or poor quality fuels, are used then the durability of the system cannot be guarant

28、eed without specific measures to be defined with the customer.Delphi reserves the right to request the customer to provide the fuel specification.6.3.2. Rail pressure limits/Delphis responsibilityThe demanded pressure must be within minimal and maximal limits that vary against speed. This limitation

29、 is generic, specific limitation for each application will be provided in system objective specification. Below is a generic example: 6.3.3. Fuelling limits/Delphis responsibilityThe minimum fuel demand for pilot injection is a function of rail pressure. It is intended to be able to guarantee that a

30、t least 0.5mm/shot is injected into the engine taking into account shot-to-shot and variation of mean delivery, as controlled by APC. This limitation is generic, specific limitation for each application will be provided in system objective specification.Below is a generic example shows the minimum d

31、elivery limit: 6.3.4. Pilot and main injections separation limits/Delphis responsibility:Taking into account the I2C and the APC strategies and low battery operation, the minimum useable electric separation should be set at the beginning at 1000 s (start to start). The shown example is generic. Spec

32、ific limitation for each application will be provided in system objective specification to allow more calibration possibilities. 7 Nozzle definition/customers responsibilityOnce the engine limits and system limits are created, the next step in the development process is to choose the hydraulic components which will allow the performance targets.7.1. PurposeThe first purpose of the engine bench development