# US 2018/0025559 A1 · Diagnostic testing of rapid heat up of an exhaust sytem during engine decompression > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0025559 A1 - Document ID: US20180025559A1 - Status: Published application - Kind: A1 - Application number: 15/218,686 - Filed: 2016-07-25 - Published: 2018-01-25 - Earliest claimed: 2016-07-25 - Assignees: Robert Bosch GmbH - Applicants: Robert Bosch GmbH - Inventors: Brent Keppy - Web page: https://patentgrep.com/patent/US20180025559A1 ## CPC - G07C 5/0808: {Diagnosing performance data (testing of vehicles G01M17/00; testing of electrical installation on vehicles G01R31/005)} - G01M 15/046: {by monitoring revolutions (for detecting misfire G01M15/11)} - G07C 5/0816: {Indicating performance data, e.g. occurrence of a malfunction} - G07C 2205/02: using a vehicle scan tool - G07C: TIME OR ATTENDANCE REGISTERS; REGISTERING OR INDICATING THE WORKING OF MACHINES; GENERATING RANDOM NUMBERS; VOTING OR LOTTERY APPARATUS; ARRANGEMENTS, SYSTEMS OR APPARATUS FOR CHECKING NOT PROVIDED FOR ELSEWHERE - G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR ## Abstract A method and a device for performing diagnostics on a vehicle. The diagnostic system includes a sensor configured to sense an operating speed of an engine of the vehicle, a diagnostic output device, and an electronic processor. The electronic processor is communicatively coupled to the sensor and the diagnostic output device. The electronic processor is configured to activate and deactivate a decompression mode of the engine. The electronic processor acquires the operating speed of the engine from the sensor and determines an engine roughness based on the operating speed of the engine. When the engine roughness is below a threshold, the electronic processor sends a diagnostic signal to the diagnostic output device. ## Claims ### Claim 1 A diagnostic system for monitoring a vehicle, the diagnostic system comprising: a sensor configured to sense an operating speed of an engine of the vehicle; a diagnostic output device; and an electronic processor communicatively coupled to the sensor and the diagnostic output device, the electronic processor configured to activate a decompression mode of the engine; acquire the operating speed of the engine from the sensor; determine an engine roughness based on the operating speed of the engine; and when the engine roughness is above a threshold, send a diagnostic signal to the diagnostic output device. ### Claim 2 (depends on 1) The diagnostic system of claim 1, wherein the electronic processor is configured to acquire the operating speed of the engine by sensing a rotational speed of a crankshaft of the engine with the sensor. ### Claim 3 (depends on 1) The diagnostic system of claim 1, wherein the electronic processor is configured to acquire the operating speed of the engine by sensing a rotational speed of a camshaft of the engine with the sensor. ### Claim 4 (depends on 1) The diagnostic system of claim 1, wherein the electronic processor is further configured to open exhaust values in the engine when a fuel supply to the engine is inactive during the decompression mode. ### Claim 5 (depends on 1) The diagnostic system of claim 1, wherein the electronic processor is configured to activate the decompression mode of the engine when the electronic processor receives a request for rapid heat up of an exhaust system of the vehicle. ### Claim 6 (depends on 1) The diagnostic system of claim 1, wherein the electronic processor is configured to activate the decompression mode of the engine when a portion of an exhaust system of the vehicle is at a temperature that is below a temperature threshold. ### Claim 7 (depends on 1) The diagnostic system of claim 1, wherein the electronic processor is configured to send the diagnostic signal only when the decompression mode is active. ### Claim 8 (depends on 1) The diagnostic system of claim 1, wherein the electronic processor is configured to diagnose a malfunction occurring in the decompression mode of the engine. ### Claim 9 (depends on 8) The diagnostic system of claim 8, wherein the electronic processor is configured to diagnose the malfunction in the decompression mode of the engine by detecting a malfunction of one or more intake or exhaust valves of the engine during the decompression mode. ### Claim 10 A method of performing diagnostics for a vehicle, the method comprising: activating, by an electronic processor, a decompression mode of an engine; acquiring, with the electronic processor, an operating speed of the engine from a sensor; determining, with the electronic processor, an engine roughness based on the operating speed of the engine; and sending a diagnostic signal to a diagnostic output device when the engine roughness is below a predetermined threshold. ### Claim 11 (depends on 10) The method of claim 10, wherein acquiring the operating speed of the engine includes sensing a rotational speed of a crankshaft of the engine with the sensor. ### Claim 12 (depends on 10) The method of claim 10, wherein acquiring the operating speed of the engine includes sensing a rotational speed of a camshaft of the engine with the sensor. ### Claim 13 (depends on 10) The method of claim 10, the method further comprising: opening exhaust values in the engine when a fuel supply to the engine is inactive during the decompression mode. ### Claim 14 (depends on 10) The method of claim 10, wherein activating the decompression mode of the engine occurs when the electronic processor receives a request for rapid heat up of an exhaust system of the vehicle. ### Claim 15 (depends on 10) The method of claim 10, wherein activating the decompression mode of the engine occurs when a portion of an exhaust system of the vehicle is at a temperature that is below a temperature threshold. ### Claim 16 (depends on 10) The method of claim 10, wherein sending the diagnostic signal only occurs when the decompression mode is active. ### Claim 17 (depends on 10) The method of claim 10, the method further comprising: diagnosing a malfunction occurring in the decompression mode of the engine. ### Claim 18 (depends on 17) The method of claim 17, wherein diagnosing a malfunction occurring in the decompression mode of the engine includes detecting a malfunction of one or more intake or exhaust valves in the engine during the decompression mode.