Sensors - Revision history

Johannesla: /* Infrared Temperature Sensors */

2023-04-14T18:47:25Z

Infrared Temperature Sensors

Johannesla at 18:45, 14 April 2023

2023-04-14T18:45:16Z

SpookySimon: /* Air Temperature Sensors */ removing condescending editorializing saying air temp compensation should be considered a MUST, who cares man, its not as variable as everyone seems to think, plus youre gonna want to calibrate the temp sensor which most teams dont do anyways meaning theyre really just flying blind, MAP compensation or even TPS speed compensation is more important but theyre harder for people to understand so they dont get the same attention

2023-03-27T20:52:12Z

Air Temperature Sensors: removing condescending editorializing saying air temp compensation should be considered a MUST, who cares man, its not as variable as everyone seems to think, plus youre gonna want to calibrate the temp sensor which most teams dont do anyways meaning theyre really just flying blind, MAP compensation or even TPS speed compensation is more important but theyre harder for people to understand so they dont get the same attention

SpookySimon: /* Powertrain: Internal Combustion */ 2 thermos for rad performance

2023-03-27T20:43:50Z

Powertrain: Internal Combustion: 2 thermos for rad performance

SpookySimon: /* Powertrain: Internal Combustion */ link to etc page

2023-03-27T20:41:33Z

Powertrain: Internal Combustion: link to etc page

SpookySimon: /* Powertrain: Internal Combustion */ adding more specific information to the uses of these sensors

2023-03-27T20:40:22Z

Powertrain: Internal Combustion: adding more specific information to the uses of these sensors

Donnellca: header for PWM

2022-04-09T01:12:20Z

header for PWM

Donnellca: details on GPS, hall effect, switched sensors

2022-04-09T01:11:08Z

details on GPS, hall effect, switched sensors

RealHumanBean: /* Air Temperature Sensors */

2021-11-16T22:57:14Z

Air Temperature Sensors

RealHumanBean: /* Liquid Temperature Sensors */

2021-11-16T22:53:27Z

Liquid Temperature Sensors

@@ Line 41: / Line 41: @@
 ====Infrared Temperature Sensors====
 ==Signal Types==
 ===Analog Sensors===

@@ Line 221: / Line 221: @@
 |-
 |Motor position
-|Determines what angle the motor is at so the inverter can time the AC phases
+|Determines what angle the motor is at so the inverter can time the AC phases (see [[Motor_Control#Field%20Oriented%20Control%20for%20Synchronous%20Machines|FOC]])
 |Resolver, encoder, or hall effect sensor
 |-

@@ Line 38: / Line 38: @@
 ====Air Temperature Sensors====
-During testing, the team should record the ambient weather conditions (humidity, any rainfall past or present, visibility, etc.). On the vehicle itself, an air temperature sensor mounted on the intake plenum can be used to adjust the fuel injector flow rate to compensate for temperature driven air density changes. This should be considered an almost essential powertrain sensor for engine tuning. Engine exhaust temperature sensors in the exhaust headers can also provide information on the vehicles performance for design evaluation; if two header temperatures differ significantly, that indicates that there is an issue with the spark/fuel flow/air flow/leakage for one of the cylinders.
+During testing, the team should record the ambient weather conditions (humidity, any rainfall past or present, visibility, etc.). On the vehicle, an air temperature sensor mounted on the intake plenum can be used to adjust the fuel injector flow rate to compensate for temperature driven air density changes. Air at 0 C is 101% as dense as air at 35 C, yielding more oxygen <!--citation needed-->. This compensation is included in almost every engine control software and the ease of implementation leads it to be one of the most common compensations used. Engine exhaust temperature sensors in the exhaust headers can also provide information on the vehicles performance for design evaluation; if two header temperatures differ significantly, that indicates that there is an issue with the spark/fuel flow/air flow/leakage for one of the cylinders.
 ====Infrared Temperature Sensors====

@@ Line 176: / Line 176: @@
 |-
 |Coolant temperature (CLT)
-| Used as an approximation as engine temperature. Verify that the engine isn't about to blow up, can be used as a compensation parameter for engine control such as during a cold start
+| Used as an approximation as engine temperature. Verify that the engine isn't about to blow up, can be used as a compensation parameter for engine control such as during a cold start. An additional temperature sensor can be used in the coolant loop after the radiator to quantify radiator performance.
 |Liquid temperature sensor
 |-

@@ Line 160: / Line 160: @@
 |-
 |Accelerator pedal position sensor (APPS)
-|Required for ETC
+|Required for [[Electronic_Throttle_Control|ETC]]
 |Rotary position sensor or potentiometer
 |-

@@ Line 147: / Line 147: @@
 {| class="wikitable"
 |-
-|'''Sensor name'''
+!Sensor name
-|'''Use'''
+!Use
-|'''Sensor type'''
+!Sensor type
 |-
 |Cam position
@@ Line 164: / Line 164: @@
 |-
 |Throttle position sensor (TPS)
-|Required for ETC, helps determine how much fuel the engine needs
+|Required for [[Engine_Control#Alpha-n|&alpha;-n engine control]], ETC, can be used as compensation parameter for speed-density or MAF control
 |Rotary position sensor or potentiometer
 |-
 |Manifold/intake air pressure (MAP/IAP)
-|Determines how much fuel the engine needs
+|Measures intake air pressure before it goes into the engine, typically in the plenum. Required for speed density control, can be used as compensation parameter for &alpha;-n control
 |Air pressure sensor<br />
 |-
 |Manifold/intake air temperature (MAT/IAT)
-|Calibrates AFR for the temperature of the air
+|Measures the temperature of the air before it goes into the engine. Can be used as compensation parameter for all engine control schemes.
 |Air temperature sensor
 |-
 |Coolant temperature (CLT)
-|Verify that the engine isn't about to blow up, tune engine for cold start
+| Used as an approximation as engine temperature. Verify that the engine isn't about to blow up, can be used as a compensation parameter for engine control such as during a cold start
 |Liquid temperature sensor
 |-
 |Coolant pressure
 |Verify that the cooling system works, diagnosing problems
 |Liquid pressure sensor
 |-
 |Fuel pressure
@@ Line 188: / Line 196: @@
 |-
 |Wideband O2
-|Tuning the car, diagnosing misfires (AFR will appear higher if a misfire is occurring)
+|Measures oxygen content of exhaust gas. Can be used as a compensation parameter for closed loop engine control. Used to tune the engine's AFR, diagnosing misfires (AFR will appear higher if a misfire is occurring). Narrowband AFR sensors are not typically used and are not recommended.
 |O2 sensor
 |-
-|Gear sensor
+|Gear position sensor
-|Display what gear the transmission is to the driver
+|Used to determine gear engine is in. Display what gear the transmission is to the driver. Not stock on all engines: CBR only has a neutral switch. Easy to create by drilling a hole in the engine block near the shift drum.
-|Rotary potentiometer?
+|Various
 |-
 |Neutral switch
@@ Line 200: / Line 208: @@
 |-
 |Vehicle speed sensor (at transmission output)
-|Verify differential performance, calculating what gear you're in
+|Verify differential performance, can be used to calculate what gear you're in
 |Hall effect sensor
 |}

@@ Line 52: / Line 52: @@
 ====Pulsed====
 Pulsed sensors send a series of digital pulses where the frequency of the pulses represents the measurement value. Commonly seen in shaft speed sensors.
-=====PWM=====
+======PWM======
 PWM sensors vary the width of pulses at a fixed frequency to represent the measurement value. Typically this is done while holding frequency steady, but technically this isn't always required. A simple analog filter can allow a PWM sensor to be approximated into an analog signal.
 ====Serial====

@@ Line 12: / Line 12: @@
 Standing for Inertial Measurement Unit, it measures orientation, velocity, and acceleration in all three axes, utilizing accelerometers, gyroscopes, and magnetometers.
 ====GPS Receivers====
-Obtains GPS data. This is usually used for logging the position of the car, so that you can see where the car is going and compare lines through corners.
+Obtains global positioning system (GPS) data from satellites. This is usually used for logging the position of the car, so that you can see where the car is going and compare lines through corners. Most commercial modules can get an accuracy around +/-3m, which is enough to plot the course of a run but not detailed dynamics. It's best used in conjunction with other sensors.
 ===Sensing Movement of a Single Component===
 ====Hall Effect Sensors====
-Detect the presence of a magnetic field. These are typically switches, that are either on or off (i.e., not analog). These are most commonly used to detect and measure rotation, e.g. of a gear. Unlike a VR sensor, they require an external magnetic force.
+Detect the presence of a magnetic field. These typically output a pulse signal corresponding to the rotation rate. These are most commonly used to detect and measure rotation, for instance gear position or wheel speed. Unlike a VR sensor, they require an external magnetic force, but this allows them to work at lower frequencies.
 ====Variable Reluctance Sensors====
-Known also as VR sensors, they detect a change in the magnetic field. Unlike hall effect sensors, they do not require an external magnetic field, so many OEMs use them for cam and crank position sensors.
+Known also as VR sensors, they detect a change in the magnetic field. Unlike hall effect sensors, they do not require an external magnetic field, so many OEMs use them for cam and crank position sensors. However, they don't work well at low frequencies, since they rely on movement and not position.
 ====Potentiometers====
 Variable resistor ladders that measure movement. The can be used as driver controls (e.g., for adjusting radio volume), or in linear form for measuring shock travel (among other uses).
@@ Line 48: / Line 48: @@
 -wire sensors take power and ground and send a output signal, usually a voltage that corresponds linearly to whatever the sensor measures. The wires are almost never interchangeable. Because they have a power input, they do not need a pullup resistor. Some 3-wire sensors, like the CBR600RR coolant temperature sensor, are actually 2-wire sensors with an internal pullup resistor.
 ===Digital Sensors===
 ====Pulsed====
 Pulsed sensors send a series of digital pulses where the frequency of the pulses represents the measurement value. Commonly seen in shaft speed sensors.
-====PWM====
+=====PWM=====
-PWM sensors vary the width of pulses at a fixed frequency to represent the measurement value. A simple analog filter can allow a PWM sensor to be approximated into an analog signal.
+PWM sensors vary the width of pulses at a fixed frequency to represent the measurement value. Typically this is done while holding frequency steady, but technically this isn't always required. A simple analog filter can allow a PWM sensor to be approximated into an analog signal.
 ====Serial====
 Some "smart" sensors transmit their measurement value(s) over a [[Communication Protocols|communication protocol]] such as CAN Bus, I<sup>2</sup>C, or SPI. This allows multiple values to be transmitted without additional wiring.

@@ Line 35: / Line 35: @@
 ===Temperature Sensors===
 ====Liquid Temperature Sensors====
 ====Air Temperature Sensors====
 ====Infrared Temperature Sensors====