With the increasing number of electronic systems in automobiles, efficient testing of highly mechatronic automotive systems presents a challenge for Chinese test engineers. This article addresses various testing issues involved in automotive R&D, and Yokogawa Electric presents a complete solution to meet the testing needs of engines, drives, vibration, environmental impact, fuel cell efficiency, and CAN bus. I. Introduction With the development of the automotive and electronics industries, more and more electronic technologies are being applied to modern automobiles. Automobiles are also evolving from simple mechanical products to advanced mechatronic products. Due to the widespread adoption of real-time driving information systems and multimedia devices, automobiles are becoming more personalized, versatile, safe, and comfortable. The rapid development of wireless and mobile computer technologies means that even driving alone in unfamiliar territory will not feel lonely or disoriented. Automobiles are no longer just a means of transportation in people's lives, but are gradually becoming a way of enjoying life. Research in automotive electronics has become one of the most active parts of automotive R&D, and achievements in this area will yield greater market returns. This article introduces various testing solutions provided by Yokogawa Electric for aspects involved in automotive R&D, including engine analysis, drive analysis, vibration analysis, environmental impact, fuel cell efficiency analysis, and CAN bus analysis (Figure 1). II. Testing of Electric Vehicle Fuel Cells For engineers engaged in automotive R&D, the following aspects are important factors affecting testing efficiency and results: (I) Various high-frequency and low-frequency, high-power and low-power electromagnetic radiation interference; (II) Common-mode voltage, vibration, and variable environment; (III) Reliability of data acquisition and analysis; (IV) Power supply and energy consumption of instruments during road tests; (V) Ease of movement and on-site use. Through communication with testing engineers of automotive manufacturing and R&D companies, Yokogawa Electric continuously improves its products to better adapt to the needs of automotive research and development. For example, to meet the research needs of electric vehicle fuel cells, Yokogawa Electric developed the DAQMaster series MX100 based on the DARWIN series. Because each cell only outputs 0.8-1.5VDC, in order to output sufficient power, a fuel cell stack generally consists of about one hundred individual cells, especially in automotive applications, where the stack may consist of six hundred individual cells. The battery voltage monitoring (CVM) system can detect problematic cells by testing the voltage of each individual cell in the battery stack structure; and analyze battery performance during long-term operation under load. Differential input is used when detecting battery voltage. Although the voltage of a single battery cell is not high, a voltage of several hundred volts can be generated between the differential input terminal and the ground of the test instrument. This voltage is called common-mode voltage. Most data acquisition instruments (DAQs) are not insulated, and their input voltage range is typically limited to 5 or 10 volts. Furthermore, non-insulated instruments are often susceptible to ground loops. To overcome the high common-mode voltage problem in fuel cell CVM systems, high-voltage insulation is required. While external signal converters or buffers can be used, many DAQ systems now incorporate buffers to ensure high signal resolution and accuracy while reducing size and cost. The MX100 DAQMaster provides the highest level of channel-to-ground, module-to-module, and channel-to-channel isolation. Additionally, its modular structure and standard software make it easy to monitor up to 1200 battery voltage channels. Simultaneously achieving high-voltage insulation and multi-channel DAQ system design is challenging because most data acquisition instrument modules use a single AD converter combined with a front-end multiplier or scan. High common-mode voltage signals must pass through switching relays before being isolated and discretized by the insulation transformer and AD converter. The MX100 uses Yokogawa's patented high-voltage solid-state semiconductor relays in its scanner to achieve multi-channel input signal switching. These relays consist of high-voltage (1500VDC), low-leakage-current (3nA) MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) and voltage-output optocouplers, offering advantages such as high-speed scanning of 10 channels within a 1-second cycle, contactless operation, long lifespan, and noiselessness. Furthermore, the MX100's internal insulation transformer and integrating AD converter are also Yokogawa patented technologies. Other DAQ systems that use electromagnetic relays for insulation suffer from switching time, switching stability, and maintenance issues. Finally, the MX100 DAQMaster provides high-performance insulation and simultaneous sampling of 4 channels because each channel of the 4-channel module uses independent hardware. For accurate waveform reproduction, the sampling rate is crucial; high-speed acquisition yields accurate data. Therefore, the MX100 has a minimum measurement cycle of 10ms, and three measurement cycles can be used in combination within a system; the measurement cycle can be set individually for each module. The MX100 supports CF cards with a maximum capacity of 2GB and initiates data backup when communication fails. When communication is restored, it automatically resumes data transmission to the PC. Designed for the high-speed, multi-channel, high-voltage, and multi-cycle characteristics of fuel cell testing, the MX100 helps test engineers improve testing efficiency and accuracy. III. CAN Bus Analysis Automotive bus technology is widely used in modern automobiles. The automotive bus provides a unified data exchange channel for various complex electronic devices, controllers, and measuring instruments within the vehicle. The number of components controlled by electronic control units (ECUs) in automobiles is increasing, such as electronic fuel injection systems, idle speed control (ISC), anti-lock braking systems (ABS), airbag systems, power windows, and active suspension. With the widespread application of integrated circuits and microcontrollers in automobiles, the number of ECUs in vehicles is also increasing. Therefore, a new concept—the Controller Area Network (CAN)—has emerged. CAN was originally developed by Bosch in Germany to solve the data exchange problem between control and testing instruments in modern automobiles. According to relevant ISO standards, CAN's topology is bus-based, hence it is also called CAN bus. With the widespread use of CAN bus, the testing and analysis of bus signals has become increasingly important in all aspects of automotive R&D, production, and maintenance, especially noise signal observation and analysis. Abnormal phenomena caused by reflected noise due to cable length, terminal impedance position, or overload level fluctuations when connecting multiple contacts can be captured and their waveforms displayed using the DL7400 series CAN signal trigger. Analysis according to the CAN protocol is displayed in a list format alongside the waveform signals. Trigger conditions can be set to fields or multiple fields of the CAN data frame (ID, Data, RTR bits, etc.). Triggering can also be activated in error frames. The captured CAN bus waveform data can be analyzed on a timeline, with the ID and data of each frame displayed in hexadecimal or binary notation. IV. Battery Voltage Fluctuations During ABS Operation The ABS control unit monitors wheel lock-up by comparing signals from speed sensors attached to each wheel. When the ABS control unit detects a locked wheel, it sends a signal to the ABS drivetrain to open a valve. The ABS drivetrain includes a spiral valve, pump, motor, and brake fluid tank. Opening the valve instantly reduces disc hydraulic pressure, weakening braking force and restoring wheel speed. Then, the disc hydraulic pressure is quickly increased again, increasing braking force through the ABS drivetrain. In other words, brake lock-up can be prevented by increasing or decreasing disc hydraulic pressure. Increasing disc hydraulic pressure, which involves pumping fluid into the cylinder, causes the pump motor to operate rapidly. This rapid motor movement affects the PWM current signal controlling the spiral valve. Normal ABS operation does not reveal whether this affects battery voltage fluctuations. Therefore, it is necessary to observe these battery voltage fluctuations. The DL750 Max.1GW long memory allows for high-speed sampling and capture of the entire braking process from start to finish. After capturing the entire process, the magnification function can be used to test specific irregularities in detail. This function automatically sets the waveform parameters for the automatic test area, including the magnified area. This magnification function can not only accurately test the irregular part in a cycle, but also automatically test the waveform parameters within the magnified area. V. Power Steering Control ECU (including inverter)/Motor Development Power steering (EPS) systems are widely used in small cars, but their application in large vehicles requiring high torque necessitates the use of 3-phase motors. Unlike traditional DC motors, testing 3-phase AC motors requires a power meter to measure power and efficiency. Furthermore, ECUs communicate via a CAN bus, necessitating testing of the CAN bus signals. The DL7400 can trigger specific IDs/data on the CAN bus, enabling synchronous observation with other signals. The general-purpose oscilloscopes DL1640/DL1740 can test ECU CPU signals, and using a 100MHz differential probe and a 150A current probe, they can also test motor inrush current, etc. The DL750 has up to 16 isolated inputs, suitable for long-term observation of inverter input/output voltage/current and ECU control signals. The WT1600 can evaluate the primary DC and secondary 3-phase current/voltage/power of the inverter in a 3-phase drive system for EPS in large vehicles, as well as inverter efficiency. Cumulative power testing can also be performed for specific operating modes. Using the WE7000's time module/CAN module/isolated A/D module/temperature module, multi-channel integrated testing can be achieved. Simultaneous long-term testing of steering angle, current consumption, voltage, temperature, and other multiple channels is possible. The CAN module can simultaneously convert data on the CAN bus into physical quantities for simultaneous testing. VI. Direct Injection Diesel Engine Injection Experiment Direct injection diesel engines can reduce fuel costs and purify exhaust emissions. The following proposes solutions for performance evaluation methods of key development aspects – high-pressure injection and electronic control: (I) Evaluation of Mechanical Design Values ​​(Injection Time and Injection Pressure) The test objects are the injection pressure of fuel injected from the nozzle, engine speed changes, and the opening and closing time of the nozzle solenoid valve. Engine development requires dynamic testing (gradually increasing engine speed to check if it meets design requirements) and static testing (checking stable operation at a fixed speed). (II) Synchronization Testing with ECU Control Signals Synchronization testing with ECU control signals tests the ECU timing and actual injection timing. VII. Summary Due to extensive cooperation with vehicle and component companies worldwide, Yokogawa Electric has many testing examples in this field. Yokogawa Electric hopes to contribute to the development of automotive electronics. Edited by: He Shiping