For many years now Renault and FEV have worked closely together on fuel consumption and emissions reduction by means of friction investigations on engines and engine components. Over the course of this cooperation, FEV has provided five friction test benches to the „Pôle d’Innovation Mécanique (PIM)”, the most recent at the Renault test center in Lardy, France. These test benches fulfill the following tasks:
• Classification and quantification of friction on engine and engine components
• Determination of new methods for friction reduction
• Determination of data as an input for friction simulation
• Examination and verification of simulation calculation results
The friction test center consists of the following test benches, all of which are equipped with asynchronous dynamometers:
• Two component test rigs for motored investigations on valve train and balancing shaft
• One motored test bench for full engine investigations (“strip method”)
• One fired test bench including a special single cylinder engine with floating liner (PIFFO)
• One fired full engine test bench
The component test rigs allow isolated investigations of valve trains and balancing shaft systems under different boundary conditions, for example, different cooling water or oil temperature. The motored full engine test bench is operated at various stationary operating points. In line with the “strip method,” after each test run additional components are removed from the engine, in order to determine their influence on the total engine friction. Since friction depends, to a large degree, on oil and material temperature, both engine oil and cooling water are controlled by conditioning systems with a very high control of accuracy. Typical tests are carried out at different temperature levels.
The PIFFO single cylinder engine is of particular interest. PIFFO stands for piston friction force measurement and is operated under fired conditions. The floating liner utilizes pressure sensors and allows the friction analysis of different materials for both liner and piston rings. Test conditions can be continuously changed with high repeatability and are achieved by FEV charge air, oil and water conditioning systems. The test field is completed by a fired full engine test bench. Here friction analysis is carried out, depending on load, speed and temperature, supported by highly precise systems for torque measurement and cylinder pressure indication.
All test benches are equipped with the FEV TCM (TestCellManager) automation system. The dynamometers are installed on unique, particularly stiff base frames in order to allow very precise torque measurement. The dynamometer controller FEV TOM (TestObjectManager) provides additional safety functions in order to protect the test object.
The conditioning systems are the central elements for charge air, oil and coolant, and are developed and built by FEV in our own production facilities. These provide precise control of the test boundary condition without any deterioration of the media quality.
The entire test field has been tested in industrial operation for several years now.