Division 3.2 Steering System

United Kingdom

For the steering pump power the standard values [W] shown in Table 2 shall be used depending on the application in combination with correction factors:

F1Table 2

Mechanical power demand of steering pump

Identification of vehicle configuration					Steering power consumption P [W]
Number of axles	Axle configuration	Chassis configuration	Technically permissible maximum laden mass (tons)	Vehicle group	Long haul			Regional delivery			Urban delivery			Municipal utility			Construction
Number of axles	Axle configuration	Chassis configuration	Technically permissible maximum laden mass (tons)	Vehicle group	U+F	B	S	U + F	B	S	U + F	B	S	U + F	B	S	U + F	B	S
2	4 × 2	Rigid lorry + (Tractor)	> 7,5 - 10	1				240	20	20	220	20	30
		Rigid lorry + (Tractor)	> 10 - 12	2	340	30	0	290	30	20	260	20	30
		Rigid lorry + (Tractor)	> 12 - 16	3				310	30	30	280	30	40
		Rigid lorry	> 16	4	510	100	0	490	40	40	430	40	50	430	30	50	580	30	70
		Tractor	> 16	5	600	120	0	540	90	40							640	50	80
	4 × 4	Rigid lorry	> 7,5 - 16	6	—
		Rigid lorry	> 16	7	—
		Tractor	> 16	8	—
3	6 × 2/2 – 4	Rigid lorry	all	9	600	120	0	490	60	40	440	50	50	430	30	50	640	50	80
		Tractor	all	10	450	120	0	440	90	40							640	50	80
	6 × 4	Rigid lorry	all	11	600	120	0	490	60	40				430	30	50	640	50	80
		Tractor	all	12	450	120	0	440	90	40							640	50	80
	6 × 6	Rigid lorry	all	13	—
		Tractor	all	14	—
4	8 × 2	Rigid lorry	all	15	—
	8 × 4	Rigid lorry	all	16													640	50	80
	8 × 6/8 × 8	Rigid lorry	all	17	—

where:

Unloaded – pumping oil without steering pressure demand

Friction – friction in the pump

Banking – steer correction due to banking of the road or side wind

Steering – steer pump power demand due to cornering and manoeuvring.

To consider the effect of different technologies, technology depending scaling factors as shown in Table 3 and Table 4 shall be applied.

Table 3

Scaling factors depending on technology

	Factor c1 depending on technology
Technology	c_{1,U + F}	c_1,B	c_1,S
Fixed displacement	1	1	1
Fixed displacement with electronical control	0,95	1	1
Dual displacement	0,85	0,85	0,85
Variable displacement, mech. controlled	0,75	0,75	0,75
Variable displacement, elec. controlled	0,6	0,6	0,6
Electric	0	1,5/η_alt	1/η_alt

with η_alt = alternator efficiency = const. = 0,7

If a new technology is not listed, the technology ‘ fixed displacement ’ shall be considered in the simulation tool.

Table 4

Scaling factor depending on number of steered axles

	Factor c2 depending on number of steered axles
Number of steered axles	Long haul			Regional delivery			Urban delivery			Municipal utility			Construction
Number of steered axles	c_2,U+F	c_2,B	c_2,S	c_2,U+F	c_2,B	c_2,S	c_2,U+F	c_2,B	c_2,S	c_2,U+F	c_2,B	c_2,S	c_2,U+F	c_2,B	c_2,S
1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1
2	1	0,7	0,7	1,0	0,7	0,7	1,0	0,7	0,7	1,0	0,7	0,7	1,0	0,7	0,7
3	1	0,5	0,5	1,0	0,5	0,5	1,0	0,5	0,5	1,0	0,5	0,5	1,0	0,5	0,5
4	1,0	0,5	0,5	1,0	0,5	0,5	1,0	0,5	0,5	1,0	0,5	0,5	1,0	0,5	0,5

The final power demand is calculated by:

If different technologies are used for multi-steered axles, the mean values of the corresponding factors c1 shall be used.

The final power demand is calculated by:

P_tot = Σ_i(P_{U + F} * mean(c_{1,U +F} ) * (c_{2i,U + F})) + Σ_i(P_B * mean(c_1,B) * (c_2i,B)) + Σ_i(P_S * mean(c_1,S) * (c_2i,S))

where:

P_tot

Total power demand [W]

Power demand [W]

c₁

Correction factor depending on technology

c₂

Correction factor depending on number of steered axles

U+F

Unloaded + friction [-]

Banking [-]

Steering [-]

Number of steered axles [-]

Annotations

Textual amendments

F1: Substituted by Commission Regulation (EU) 2019/318 of 19 February 2019 amending Regulation (EU) 2017/2400 and Directive 2007/46/EC of the European Parliament and of the Council as regards the determination of the CO2 emissions and fuel consumption of heavy-duty vehicles (Text with EEA relevance).