Challenges for modelling and integrating environmental performances in concept design: the case of an automotive component lightweighting

Figures & data

Figure 1. Workflow and data exchange within the eco-design approach for a component re-design.

Table 1. List of TB parts, materials and masses for the current solution (aluminium alloy housing TB) and the new one (PETGF housing TB).

Component	Aluminium alloy housing TB		PETGF housing TB
	Material	Mass (kg)	Material	Mass (kg)
Axial play pin	Stainless steel	1.00 × 10^−3	–	–
Axial play pin sphere	Stainless steel	9.80 × 10^−5	–	–
C-ring	–	–	Stainless steel	7.50 × 10^−3
Cover	GF polybutylene – terephthalate	6.80 × 10^−2	GF polybutylene – terephthalate	6.80 × 10^−2
Cover clips	Stainless steel	1.80 × 10^−2	Stainless steel	1.80 × 10^−2
Cover gasket	Ethylene – Propylene	2.00 × 10^−2	Ethylene – Propylene	2.00 × 10^−3
DC Motor	See Table TOT	2.25 × 10^−1	See Table TOT	2.25 × 10^−1
DC Motor screws	Carbon steel	1.80 × 10^−2	Carbon steel	2.00 × 10^−3
Double wheel	GF Polyphthalamide – Polytetrafluorethylene	7.10 × 10^−3	GF Polyphthalamide – Polytetrafluorethylene	7.10 × 10^−3
Double wheel pin	Carbon steel	6.00 × 10^−3	Carbon steel	6.00 × 10^−3
Duct insert	–	–	Aluminium	4.70 × 10^−2
End cap	Brass	1.00 × 10^−3	Brass	1.00 × 10^−3
Housing	Aluminium	4.40 × 10^−1	PET GF	2.20 × 10^−1
Idle screw	Aluminium	4.30 × 10^−3	–	–
Idle screw sphere	Aluminium	4.30 × 10^−3	–	–
Needle bearing	Stainless steel	7.00 × 10^−3	Stainless steel	7.00 × 10^−3
Shaft bushing	Stainless steel	1.90 × 10^−3	Stainless steel	1.91 × 10^−3
Spring bushing	Polyamide	8.00 × 10^−3	Polyamide	–
Spring	Stainless steel	1.20 × 10^−2	Stainless steel	1.20 × 10^−2
Shaft sector gear	GF polybutylene terephthalate	1.90 × 10^−2	GF polybutylene terephthalate	1.90 × 10^−2
Shaft	Stainless steel	5.58 × 10^−2	Stainless steel	5.58 × 10^−2
Throttle valve	Aluminium	2.44 × 10^−3	Aluminium	2.44 × 10^−3
Throttle valve screws	Carbon steel	3.58 × 10^−3	Carbon steel	3.58 × 10^−3
Entire TB mass	0.86 kg		0.67 kg

Figure 2. Environmental assessment comparison of alternative materials for the TB housing.

Figure 3. Exploded view of the current TB solution (aluminium alloy housing TB) and the new one (PETGF housing TB).

Figure 4. Details about minor design modifications due to the new housing material: co-moulded metallic duct insert in the PETGF-housing TB (a); idle screw and idle screw sphere in the Aluminium housing TB (b – Before) and PETGF-housing TB (b – After).

Figure 5. Manufacturing process map of Aluminium housing TB and PETGF-housing TB.

Table 2. Schematisation of TB LC stages and related processes included in the analysis (F = foreground process; B = background process).

	Stage	Process
TB Life Cycle	Materials supply	Production of electricity, heat, steam and fuel for raw materials extraction and production (B)
	Production	Production of electricity, heat, steam, fuel and auxiliary material for manufacturing processes (B)
		Manufacturing processes of the housing (F)
		Manufacturing processes of TB components except the housing (B)
	Logistic	Fuel production for TB internal transportations between suppliers and MM plants (F)
	Use	Production of fuel whose consumption is ascribed to TB (B)
		Air emissions due to FC ascribed to TB (B)
	EoL	Production of electricity, heat, steam and fuel for materials disassembly, shredding and recycling (B)
		Landfilling of waste materials (B)

Table 3. Input and output flow measured for the housing manufacturing technologies.

Technological process	Material/energy input		Material/energy output
	Typology	GaBi modelling	Typology
Production – Aluminium alloy housing TB
Rotary kiln	Aluminium ingot	–	Molten alluminium
	Methane	Methane [Organic intermediate products]
	Sodium chloride	Sodium chloride [ inorganics intermediate products]
Sieving and degassing	Molten aluminium	–	Molten alluminium
	Methane	Methane [Organic intermediate products]
	Nitrogen	Nitrogen gaseous [Inorganic intermediate products]
Maintenance furnace	Molten aluminium	–	Molten alluminium
	Methane	Methane [Organic intermediate products]
Pressure die casting	Molten aluminium	–	Die casted housing
	Electricity	Electricity [Electric power]
Machining (cutting, peening)	Die casted TB	–	Finished housing
	Electricity	Electricity [Electric power]	Drosses
TB assembly	Finished housing	–	Assembled TB
	Electricity	Electricity [Electric power]
Production – PETGF housing
Injection	PolyEthylene Terephthalate (PET)	PolyEthylene Terephthalate fibers (PET) [Plastics]	Finished housing
	Glass Fiber (GF)	Glass fibers [Minerals]
	Electricity	Electricity [Electric power]
TB assembly	Finished housing	–	Assembled TB
	Electricity	Electricity [Electric power]

Table 4. Use stage modelling: equations and data.

Fuel consumption calculation		• FCTB = Fuel Consumption ascribed to the TB (l/100 km) • FCcar = car Fuel Consumption (l/100 km) • kmuse = use stage mileage (km) • ΔFC = percent quota of car FC represented by the TB (%) • ΔM = percent quota of car Mass ascribable to the TB (%) • MTB = TB Mass (kg) • Mtotal = total car Mass (kg)
Emission calculation		• emissi TB = emissions of pollutant i during the entire vehicle lifetime attributable to the TB (g) • emissi km = vehicle per-kilometre emission of pollutant i (g/km)
Vehicle technical information	Vehicle model	Volkswagen Engine EA 211 four-cylinder turbocharged and direct injection TSI engines
	Mtotal (kg)	1046
	Emission stage	EURO 5
	FCcar (mixed urban-extra) (l/100 km)	5.8
	emiss CO2 km (g/km)	139
	kmuse (km)	150000

Table 5. LCIA results for aluminium housing TB and PETGF-housing TB.

	Materials supply	Production	Logistic	Use	EoL	Total LC
Aluminium alloy housing TB
ADPelements (kg Sb-eq.)	5.36E-05	1.23E-07	3.88E-09	6.85E-07	−1.29E-07	5.43E-05
EP (kg Phosphate-eq.)	4.71E-04	1.43E-04	2.14E-04	2.12E-03	−5.30E-05	2.90E-03
GWP (kg CO2 – eq)	1.70E+00	5.26E-01	1.09E-01	1.24E+01	−2.29E-01	1.45E+01
ODP (kg R11-eq.)	2.53E-08	5.60E-11	2.56E-13	8.50E-11	−7.27E-09	1.82E-08
PED (MJ)	3.36E+01	1.30E+01	1.55E+00	1.86E+02	−4.13E+00	2.30E+02
POCP (kg Ethene-eq.)	4.93E-04	1.77E-04	7.00E-05	5.05E-03	−7.79E-05	5.71E-03
PETGF-housing TB
ADPelements (kg Sb-eq.)	6.43E-05	4.35E-08	4.40E-09	5.37E-07	−5.04E-08	6.49E-05
EP (kg Phosphate-eq.)	8.14E-04	4.88E-05	2.23E-04	1.66E-03	2.65E-05	2.78E-03
GWP (kg CO2 – eq)	2.64E+00	1.87E-01	1.23E-01	9.68E+00	−8.15E-02	1.26E+01
ODP (kg R11-eq.)	4.90E-08	2.55E-11	3.11E-13	6.66E-11	−3.23E-09	4.59E-08
PED (MJ)	5.44E+01	4.20E+00	1.76E+00	1.46E+02	−1.41E+00	2.05E+02
POCP (kg Ethene-eq.)	6.63E-04	5.71E-05	6.00E-05	3.95E-03	−2.85E-05	4.71E-03

Figure 6. Impact of PETGF-housing TB with respect to aluminium alloy housing TB (%).

Figure 7. Contribution analysis by LC stage of impacts for aluminium alloy housing TB and PETGF-housing TB.

Figure 8. Break-even analysis based on vehicle mileage for GWP.

Figure 9. Prototypes of aluminium alloy housing (right hand) and PETGF housing (left hand).