Vacuum pumps and pressure sensor - BRIEF INFORMATION - Electrical Vacuum Pumps for Brake Booster Systems

Q: UP 28 and UP 5.0 differ in how they supply vacuum for the brake booster—how?

UP 28 generates additional vacuum for support applications when the engine does not provide enough vacuum via the intake manifold. UP 5.0 provides pneumatic vacuum supply as a stand-alone system, acting as the sole vacuum source for the brake booster and auxiliary consumers.

Q: What operating principle do the vacuum pumps use?

The pumps work on the rotary vane compressor principle: an off-centre rotor with blades compresses the enclosed volume during rotation, creating vacuum that draws air through the vacuum pump into the brake booster via the pneumatic line system.

Q: How does the pressure sensor integrate into the brake system?

The pressure sensor measures vacuum and sends an analogue output signal (0.4–4.8 V) to the brake system control unit. The control unit uses this signal to control switch-on and switch-off points of the electrical vacuum pump (UP 28 and UP 5.0).

Oct 29, 2026

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Electrical vacuum pump and pressure sensor documentation describing application variants for generating or supporting vacuum in pneumatic brake booster systems. The UP 28 variant provides additional vacuum for support applications, while the UP 5.0 can act as a stand-alone vacuum source for the brake booster and auxiliary consumers. Rotary vane compressor design, engine-independent support features, and energy-demand-based operation are detailed, along with technical specifications for performance, acoustics, protection class, wiring, and pressure sensing integration with brake control units.

LanguageEnglish

CategoryTechnology

FormatPDF

Pages5

Reading Time13 min

AccessFree to download

Vacuum pumps and pressure sensor

Application variants: UP 28 and UP 5.0

Design and function: rotary vane compressor principle

Special features

Technical details and comparison

Technical drawing and pin assignment

Pressure sensor with nonreturn valve

Pressure sensor: product features and design

Pressure sensor: application examples and technical data

BRIEF INFORMATION Vacuum pumps and pressure sensor ➔ Electrical vacuum pumps to support or independently generate the vacuum for the pneumatic brake booster system ➔ Applicable for all engine concepts, also for electric motors and hybrid drives ➔ HELLA is the market leader and has over 10 years of experience in developing and manufacturing electrical vacuum pumps PRODUCT FEATURES Application Under certain driving conditions or depending on the engine layout, no vacuum or an insufficient vacuum is supplied to the brake booster through the intake manifold of the internal combustion engine. The UP 28 variant can support the system by generating an additional vacuum (support application) . The UP 5.0 can provide the pneumatic vacuum supply as a "stand-alone" system. For this, the pump acts as the sole vacuum source and ensures an adequate supply for the brake booster and any auxiliary consumers. DESIGN AND FUNCTION ROTARY VANE COMPRESSOR PRINCIPLE The vacuum pumps' function is based on the rotary vane compressor principle. The pump contains a rotor that is off-centre to the pump chamber. The blades set in the rotor slide along the interior wall of the pump chamber. The volume enclosed by the blades is continuously compressed by rotation. This change in the chamber volume generates a vacuum causing air to be sucked in by the brake booster through the vacuum pump via the brake system's pneumatic line system. SPECIAL FEATURES ➔ Engine-independent vacuum support ➔ Flexible installation location ➔ Dry-running system (no connection to the lubricating oil circuit required and maintenance-free)➔ Further use of conventional brake systems for alternative drive systems, such as hybrid and electric drives ➔ Reduction of energy consumption due to demand-based use ➔ Support for complying with legal requirements to reduce pollutant emissions Technical details | UP 28 | | UP 5.0 | | --- | --- | --- | | Product photo
Description Rated voltage Average current consumption between
thresholds Service life Maximum vacuum Time to reduce by 50 % of ambient pressure Time to reduce by 70 % of ambient pressure Booster size Operating temperature Acoustics
Protection class | | | | | ➔ Rotor and pump chamber
eccentrically fixed
➔ 5-wing technology
➔ Typical for support applications 13.5 V < 10 A 600 h 86 %(≥ 88 % typical) ≤ 5.5 s ≤ 11 s 3.2 l -40 to +100 °C < 70 db (A)
IP 6K9K
➔ Rotor with 8 blades, optimised shape of pump chamber
➔ Plastic silencers with specific shape for noise improvement
➔ Typical for "stand-alone" applications 13 V 16 A 1,500 h ≥ 90 % ≤ 3.0 s ≤ 6.0 s 5 l -40 to +120 °C < 73 db (A)
IP 6K9K | | Technical drawing UP 28-with engine compartment plug UP 28 – with relay box Pin assignment 1 Engine terminal "+" 2 Engine terminal "-" 1 Terminal 31- 2 Signal low-active (engine control unit) 5 Terminal 30 + 1 Engine terminal "+" 2 Engine terminal "-" UP 5.0 – with engine compartment plug Comparison of vacuum curves UP 28 ~ UP 5.0 Absolute pressure (mbar) Time (s) UP 28 UP 5.0 Booster volume = 4 L Voltage = 13 V Temperature = RT COMPARISON of support and "stand-alone" application TECHNICAL DETAILS Support application UP 28 | Further vacuum
consumers | | Vacuum generated by engine | | --- | --- | --- | | | | | | Pressure sensor with nonreturn | | | --- | --- | | valve | | UP 28 Brake booster Existing or separate control unit "Stand-alone" application UP 5.0 Electrical connection Programme overview UP 28 – with relay box 1 pc. 8TG 008 570-021 6 pcs. 8TG 008 570-027 UP 28-with engine compartment plug 1 pc. 8TG 009 428-081 6 pcs. 8TG 009 428-087 UP 5.0 – with engine compartment plug 1 pc. 8TG 012 377-701 10 pcs. 8TG 012 377-707 PRESSURE SENSOR WITH NONRETURN VALVE Product features ➔ Can be fully integrated into the vacuum system of the brake boost ➔ Compact design ➔ Simple mechanical connection A

FAQs

UP 28 and UP 5.0 differ in how they supply vacuum for the brake booster—how?

UP 28 generates additional vacuum for support applications when the engine does not provide enough vacuum via the intake manifold. UP 5.0 provides pneumatic vacuum supply as a stand-alone system, acting as the sole vacuum source for the brake booster and auxiliary consumers.

What operating principle do the vacuum pumps use?

The pumps work on the rotary vane compressor principle: an off-centre rotor with blades compresses the enclosed volume during rotation, creating vacuum that draws air through the vacuum pump into the brake booster via the pneumatic line system.

How does the pressure sensor integrate into the brake system?

The pressure sensor measures vacuum and sends an analogue output signal (0.4–4.8 V) to the brake system control unit. The control unit uses this signal to control switch-on and switch-off points of the electrical vacuum pump (UP 28 and UP 5.0).

Oct 29, 2026

Upload by วิน