ALM (Accurate Lambda Meter) is a high-precision air-fuel-ratio (AFR) meter that detects the air-fuel ratio of the exhaust gas by measuring the oxygen concentration in the engine exhaust. ALM-Inline is one kind of our ALM products. ALM-Inline has a solid black plastic shell. It is more effective in preventing the circuit board from being damaged the volume is small. It eliminates the sensor wire. the sensor connector is fixed to the plastic shell and the appearance is more beautiful. it is more convenient to use.

ALM-Inline uses the Bosch CJ125 chip, which can accurately measure the oxygen concentration that can be converted to λ, AFR or other parameters required by the user. ALM-Inline uses a more advanced LSU4.9 oxygen sensor, rather than the LSU4.2 used by most other air-fuel ratio analyzers, and ALM-Inline uses a closed-loop module to control the temperature of the oxygen sensor to keep the LSU4.9 wide-area oxygen sensor temperature accurately At 780°C. LSU4.9 is a new wide-area oxygen sensor developed from LSU 4.2, which is superior to LSU 4.2, and Bosch has used LSU4.9 wide-area oxygen sensors for its automotive inspection equipment.

Bosch chip CJ125 is the integrated chip (IC) specifically designed for LSU 4.9 Sensors. Bosch’s own wideband controller, “Lambda Tronic”, uses CJ125 driver chip. In fact, Bosch uses this chip wherever a LSU sensor is used. The CJ125 and LSU sensor are mated-pair by Bosch. Presumably LSU sensors work the best with CJ125 chips.

See here for Bosch Motorsport’s wideband controller, LT4:

The link may be updated by Bosch, please use the link on our website.

ALM uses the LSU 4.9 wideband sensor by default, and it can also use LSU ADV wide-area oxygen sensor, but need to update the software, if the customer wants to use LSU ADV sensor, please explain in advance

List of ALM-Inline parts
Small ALM Inline: 3.64″ x 1.18″ x 0.87″
Bosch LSU 4.9 sensor
Stainless plug and bung

ALM-Inline technical specifications

Power supply
Input voltage range    DC 12V for the Inline, 12V for the O2 sensor
Input current       60mA typical for the Inline; the heater current directly from 12V supply

Standard configuration   LSU 4.9 (Support LSUADV;
              LSU 4.2 capable but not recommended)
Number of Sensors     One
Free air calibration    No need

Range of measurement    λ = 0.5 ~ ∞
Measurement accuracy    ±0.008 @ λ=1.00
              ±0.01 @ λ=0.80
              ±0.05 @ λ=1.70
Air/Fuel Ratio       Fuel dependent (see lambda range and accuracy)
Range of O2%        -21% ~ 21%

Response time
5ms updating rate
0-5v analog output in 5ms updating rate;

Control         Built-in PID control with CJ125
Current         Typical 1A;Peak 3.5A
Heater return (H-)    Separate wire from Ground

Lambda analog output    0 ~ 5V analog the user can set
Analog accuracy       ±0.005V error with a 10-bit DAC chip

SCI communications(option)

CPU         Freescale MC9S12P128 16-bit micro-processor (Automotive level)
Speed        32MHz
Memory        128k Flash, 6k RAM, 4k Data

Special features
On-Inline-Diagnosis and error report
Self-learning of part-to-part variations, aging effect
Working with different types of fuels (gasoline, diesel, E85, etc)

Temperature range    -40oC ~ 85oC
Dimensions        3.64″ x 1.18″ x 0.87″

Appendix:LSU4.9 vs  LSU4.2

Characteristics LSU4.2 LSU4.9 Notes
lambda range lambda = 0.65 ~ ∞ lambda = 0.65 ~ ∞  
Accuracy only good at
lambda = 1 or moderate rich
accurate at
both rich and lean, wider range
LSU4.2 is only accuracy at lambda ≈1 and moderate rich, between 0.8~1.0 lambda;
LSU4.9 has better accuracy in both rich and lean conditions, suitable for gasoline, diesel, CNG, etc.
Response time Slower Faster Thinner sensing element of LSU 4.9 makes it more responsive to the AFR change, dynamically more accurate, and easier to light off, less heating power needed.
Heating power 10W 7.5W LSU4.2 has the off-centered-heater vs. LSU 4.9 has the centered-heater in the laminate;
LSU4.9 has better heating efficiency, less heating power needed.
Free air
needed not needed LSU4.2 is susceptible to reference air contaminations, which is called CSD (characteristic shift down), requires frequent free-air calibrations.
LSU4.9 uses reference pump current instead of reference air. No more CSD. No requirement of free-air calibrations
Nernst cell
resistance vs. temperature
80~750C 30~790C LSU4.9 has higher resolution of internal resistance vs. temperature characteristics, which makes the temperature measurement more accurate, and better heater control, therefore higher accuracy of lambda.
Light off time long short LSU4.9 lights off faster. Lambda controls can be active much faster during warm up phase.
Reliability   Improved reliability LSU4.9 is superior to LSU4.2 with regard to the reliability and life.
Check with Bosch Still selling it Recommended Bosch recommends LSU4.9 to all OEMs.
Bosch uses LSU4.9 for its own wideband controller.

Software and Documentation
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